United States Office of Research and EPA/625/R-95/001

Environmental Protection Development September 1995

Agency Washington, DC 20460

1EPA Process Design Manual

Land Application of

Sewage Sludge and

Domestic Septage
EPA/625/R-95/001

September 1995

Process Design Manual

Land Application of Sewage Sludge and

Domestic Septage

U.S. Environmental Protection Agency

Office of Research and Development

National Risk Management Research Laboratory

Center for Environmental Research Information

Cincinnati, Ohio
Notice

This document has been reviewed in accordance with the U.S. Environmental Protection Agency’s

peer and administrative review policies and approved for publication. Mention of trade names or

commercial products does not constitute endorsement or recommendation for use.

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Contents

Page

Chapter 1 Introduction

1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Sewage Sludge Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 Objectives of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.4 Scope of Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Chapter 2 Overview of Sewage Sludge Land Application Practices

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 Application to Agricultural Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2.1 Purpose and Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2.2 Advantages of Agricultural Land Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2.3 Limitations of Agricultural Land Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.3 Application to Forest Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.3.1 Purpose and Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.3.2 Advantages of Forest Land Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.3.3 Limitations of Forest Land Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Land Application at Reclamation Sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4.1 Purpose and Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4.2 Advantages of Land Application at Reclamation Sites . . . . . . . . . . . . . . . . . . . . . . 9

2.4.3 Limitations of Land Application at Reclamation Sites. . . . . . . . . . . . . . . . . . . . . . . 9

2.5 Land Application at Public Contact Sites, Lawns, and Home Gardens . . . . . . . . . . . . . . . 9

2.5.1 Purpose and Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.5.2 Advantages of Land Application at Public Contact Sites, Lawns, and 

Home Gardens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.5.3 Limitations of Land Application at Public Contact Sites, Lawns, and Home

Gardens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Chapter 3 Overview of the Part 503 Regulatory Requirements for Land Application of 

Sewage Sludge

3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.2 Pollutant Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.2.1 Ceiling Concentration Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

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3.2.2 Pollutant Concentration Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2.3 Cumulative Pollutant Loading Rates (CPLRs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2.4 Annual Pollutant Loading Rates (APLRs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.2.5 Why Organic Pollutants Were Not Included in Part 503 . . . . . . . . . . . . . . . . . . . . 14

3.3 Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.4 Operational Standards for Pathogens and Vector Attraction Reduction . . . . . . . . . . . . . . . 15

3.4.1 Pathogen Reduction Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.4.2 Vector Attraction Reduction Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.5 Frequency of Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.6 Recordkeeping and Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.7 Sewage Sludge Quality and the Part 503 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.7.1 Exceptional Quality (EQ) Sewage Sludge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.7.2 Pollutant Concentration (PC) Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3.7.3 Cumulative Pollutant Loading Rate (CPLR) Sewage Sludge. . . . . . . . . . . . . . . . . 24

3.7.4 Annual Pollutant Loading Rate (APLR) Sewage Sludge . . . . . . . . . . . . . . . . . . . . 24

3.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Chapter 4 Characteristics of Sewage Sludge

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.2 Sewage Sludge Quantity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.3 Total Solids Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.4 Volatile Solids Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.5 pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.6 Organic Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.7 Pathogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

4.8 Nutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.8.1 Nitrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.8.2 Phosphorous, Potassium, and Other Nutrients. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.9 Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.10 Organic Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.11 Hazardous Pollutants (If Any). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.12 Types of Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.12.1 Primary Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.12.2 Secondary Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.12.3 Tertiary Sewage Sludge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.12.4 Domestic Septage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

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4.13 Effects of Wastewater and Sludge Treatment Processes on Sewage Sludge

Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.14 Effects of Pretreatment and Pollution Prevention Programs on Sewage Sludge

Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

4.15 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Chapter 5 Site Evaluation and Selection Process

5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.2 Part 503 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.2.1 Protection of Surface Water and Wetlands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.2.2 Protection of Threatened and Endangered Species. . . . . . . . . . . . . . . . . . . . . . . . 40

5.2.3 Site Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.3 Planning and Selection Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.4 Preliminary Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.4.1 Institutional and Regulatory Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.4.2 Public Participation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.4.3 Preliminary Land Area Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.4.4 Sewage Sludge Transport Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.5 Phase I Site Evaluation and Site Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.5.1 Existing Information Sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.5.2 Land Use and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

5.5.3 Physical Characteristics of Potential Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

5.5.4 Site Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5.6 Phase II Site Evaluation: Field Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5.7 Selection of Land Application Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

5.8 Final Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

5.8.1 Preliminary Cost Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

5.8.2 Final Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

5.9 Site Selection Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.9.1 City Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.9.2 Sewage Sludge and Soil Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.9.3 Regulations Considered. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.9.4 Public Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.9.5 Preliminary Feasibility Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.9.6 Estimate Land Area Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.9.7 Eliminate Unsuitable Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

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5.9.8 Identify Suitable Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

5.9.9 Phase II Site Survey and Field Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

5.9.10 Cost Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

5.9.11 Final Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

5.10 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Chapter 6 Phase II Site Evaluation

6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.2 Preliminary Field Site Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.3 Site-Specific Field Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.1 Base Map Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.2 Field Checking of Surface Features and Marking Buffer Zones on 

the Base Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.3 Identifying Topographic Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.3.4 Field Soil Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.3.5 Delineation of Floodplains and Wetlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

6.3.6 Site Hydrogeology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

6.4 Soil Sampling and Analysis to Determine Agronomic Rates . . . . . . . . . . . . . . . . . . . . . . . . 61

6.4.1 Part 503 Definition of Agronomic Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

6.4.2 Soil Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

6.5 Special Considerations for Reclamation Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

6.5.1 Sampling and Analysis of Disturbed Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Chapter 7 Process Design for Agricultural Land Application Sites

7.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.2 Regulatory Requirements and Other Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.2.1 Nitrogen and Other Nutrients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.2.2 Soil pH and Requirements for pH Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

7.2.3 Special Considerations for Arid Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.3 Application Methods and Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.3.1 Application Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.3.2 Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

7.3.3 Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

7.4 Determining Sewage Sludge Application Rates for Agricultural Sites. . . . . . . . . . . . . . . . . 68

7.4.1 Part 503 Agronomic Rate for N and Pollutant Limits for Metals . . . . . . . . . . . . . . 68

7.4.2 Crop Selection and Nutrient Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

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7.4.3 Calculating Residual N, P, and K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

7.4.4 Calculation of Annual Application Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

7.4.5 Calculation of Supplemental N, P, and K Fertilizer. . . . . . . . . . . . . . . . . . . . . . . . . 81

7.4.6 Use of Computer Models To Assist in Determining Agronomic Rates . . . . . . . . . . 81

7.5 Design Example of Sewage Sludge Application Rate Calculations . . . . . . . . . . . . . . . . . . 82

7.5.1 Calculation of Agronomic N Rate for Each Field . . . . . . . . . . . . . . . . . . . . . . . . . . 82

7.5.2 Calculation of Long-Term Pollutant Loadings and Maximum Sewage 

Sludge Quantities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

7.5.3 Calculation of Agronomic P Rate for Each Field . . . . . . . . . . . . . . . . . . . . . . . . . . 84

7.5.4 Calculation of Supplemental K Fertilizer To Meet Crop Nutrient Requirements . . 90

7.5.5 Additional Considerations for Land Application Program Planning . . . . . . . . . . . . 91

7.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Chapter 8 Process Design for Forest Land Application Sites

8.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.2 Regulatory Requirements and Other Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.2.1 Pathogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.2.2 Nitrogen Dynamics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.3 Effect of Sewage Sludge Applications on Tree Growth and Wood Properties . . . . . . . . . . 96

8.3.1 Seedling Survival . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.3.2 Growth Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.3.3 Wood Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.4 Effect of Sewage Sludge Application on Forest Ecosystems . . . . . . . . . . . . . . . . . . . . . . . 96

8.5 Forest Application Opportunities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8.5.1 Forest Stand Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8.5.2 Christmas Tree Plantations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8.6 Equipment for Sewage Sludge Application at Forest Sites . . . . . . . . . . . . . . . . . . . . . . . . . 99

8.6.1 Transfer Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8.6.2 Application Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8.7 Scheduling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

8.8 Determining Sewage Sludge Application Rates for Forest Sites . . . . . . . . . . . . . . . . . . . . 100

8.8.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

8.8.2 Nitrogen Uptake and Dynamics in Forests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

8.8.3 Calculation Based on Nitrogen for a Given Year . . . . . . . . . . . . . . . . . . . . . . . . . . 103

8.8.4 Calculation of Sewage Sludge Application Rates for First and Subsequent

Years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

8.8.5 Calculation Based on Part 503 Pollutant Limits for Metals . . . . . . . . . . . . . . . . . . 104

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8.9 Design Example of Sewage Sludge Application at Forest Sites. . . . . . . . . . . . . . . . . . . . . 104

8.9.1 Sewage Sludge Quantity and Quality Assumptions . . . . . . . . . . . . . . . . . . . . . . . . 104

8.9.2 Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

8.9.3 Determining the Sewage Sludge Application Rate Based on Nitrogen . . . . . . . . . 105

8.9.4 Site Capacity Based on Nitrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

8.10 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Chapter 9 Process Design for Land Application at Reclamation Sites

9.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

9.2 Consideration of Post-Sewage Sludge Application Land Use. . . . . . . . . . . . . . . . . . . . . . . 110

9.2.1 Mining Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

9.3 Nutrients, Soil pH, and Climate Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

9.3.1 Nutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

9.3.2 Soil pH and pH Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

9.3.3 Factors Affecting Crop Yields at Reclamation Sites . . . . . . . . . . . . . . . . . . . . . . . . 113

9.3.4 Special Considerations for Arid Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

9.4 Vegetation Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

9.4.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

9.4.2 Seeding and Mulching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

9.5 Sewage Sludge Application Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

9.5.1 Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

9.5.2 Site Preparation Prior to Sewage Sludge Application. . . . . . . . . . . . . . . . . . . . . . . 119

9.5.3 Methods of Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

9.5.4 Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

9.6 Scheduling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

9.7 Determining Sewage Sludge Application Rates at Reclamation Sites . . . . . . . . . . . . . . . . 120

9.7.1 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

9.7.2 Approach for Determining a Single, Large Application of Sewage Sludge at a

Reclamation Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

9.7.3 Design Example for a Single, Large Sewage Sludge Application at a 

Reclamation Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

9.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Chapter 10 Land Application at Public Contact Sites, Lawns, and Home Gardens

10.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.2 Part 503 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.3 Marketing of Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

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10.3.1 Developing Product Demand. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10.3.2 Marketing Cost Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10.4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Chapter 11 Land Application of Domestic Septage

11.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

11.1.1 Definition of Domestic Septage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

11.1.2 Domestic Septage Versus Industrial/Commercial Septage. . . . . . . . . . . . . . . . . . . 130

11.2 Regulatory Requirements for Land Application of Domestic Septage . . . . . . . . . . . . . . . . 130

11.2.1 Determining Annual Application Rates for Domestic Septage at Agricultural 

Land, Forests, or Reclamation Sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

11.2.2 Pathogen Reduction Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

11.2.3 Vector Attraction Reduction Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

11.2.4 Certification Requirements for Pathogen and Vector Attraction Reduction . . . . . . 132

11.2.5 Restrictions on Crop Harvesting, Animal Grazing, and Site Access . . . . . . . . . . . 133

11.2.6 Recordkeeping and Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

11.2.7 Part 503 Required Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

11.2.8 State Requirements for Domestic Septage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

11.3 Adjusting the pH of Domestic Septage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

11.3.1 Sampling for pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

11.4 Methods of Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

11.5 Operation and Maintenance at Land Application Sites Using Domestic Septage . . . . . . . 137

11.6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Chapter 12 Public Participation

12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

12.2 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

12.3 Implementation of a Public Participation Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

12.3.1 Initial Planning Stage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

12.3.2 Site Selection Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

12.3.3 Site Design Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

12.3.4 Site Preparation and Operation Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

12.4 Special Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

12.4.1 Agricultural Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

12.4.2 Forest Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

12.4.3 Reclamation Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

12.5 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

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Chapter 13 Monitoring and Sampling

13.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

13.2 Sewage Sludge Monitoring and Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

13.2.1 Sampling Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

13.2.2 Frequency of Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

13.2.3 Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

13.2.4 Analytical Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

13.3 Soil Monitoring and Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

13.3.1 Sampling Location and Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

13.3.2 Number of Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

13.3.3 Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

13.3.4 Analytical Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

13.4 Surface-Water and Ground-Water Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.4.1 Surface-Water Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.4.2 Ground-Water Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.5 Vegetation Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.6 Monitoring and Sampling at Reclamation Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.6.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.6.2 Disturbed Soil Sampling Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.6.3 Suggested Monitoring Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

13.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Chapter 14 General Design Considerations

14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

14.2 Transportation of Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

14.2.1 Transport Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

14.2.2 Vehicle Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

14.2.3 Pipeline Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

14.2.4 Other Transport Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

14.3 Storage of Sewage Sludge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

14.3.1 Storage Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

14.3.2 Storage Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

14.3.3 Location of Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

14.3.4 Storage Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

14.4 Land Application Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

14.4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

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14.4.2 Application of Liquid Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

14.4.3 Application of Dewatered Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

14.5 Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

14.5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

14.5.2 Protection of Ground Water and Surface Water Quality. . . . . . . . . . . . . . . . . . . . . 177

14.5.3 Grading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.5.4 Erosion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.6 Design of Supporting Facilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.6.1 Access Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.6.2 Public Access: Site Fencing and Security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.6.3 Equipment and Personnel Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

14.6.4 Lighting and Other Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

14.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Chapter 15 Management, Operational Considerations, and Recordkeeping and Reporting

15.1 Sewage Sludge Management Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

15.2 Part 503 Requirements Affecting Land Application Site Operation . . . . . . . . . . . . . . . . . . . 181

15.3 Nuisance Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

15.3.1 Odor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

15.3.2 Spillage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

15.3.3 Mud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

15.3.4 Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

15.3.5 Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

15.3.6 Road Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

15.3.7 Selection of Haul Routes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

15.4 Safety Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

15.4.1 Training. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

15.5 Health Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

15.5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

15.5.2 Personnel Health Safeguards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

15.6 Recordkeeping and Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

15.6.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

15.6.2 Part 503 Recordkeeping Requirements for Preparers of Sewage Sludge. . . . . . . 185

15.6.3 Part 503 Requirements for Appliers of Sewage Sludge . . . . . . . . . . . . . . . . . . . . . 192

15.6.4 Notification Requirements for Preparers and Appliers of Sewage Sludge. . . . . . . 192

15.6.5 Notice of Interstate Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

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15.6.6 Notification by Appliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

15.6.7 Annual Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

15.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

Chapter 16 Cost Estimate Guidance for Land Application Systems

16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

16.1.1 Information Needed Prior to Using Cost Algorithms. . . . . . . . . . . . . . . . . . . . . . . . 197

16.1.2 Economic Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

16.1.3 Total Base Capital Cost Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

16.1.4 Total Annual O&M Cost Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

16.1.5 Calculating Cost Per Dry Ton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

16.2 Agricultural Land Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

16.2.1 General Information and Assumptions Made . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

16.2.2 Process Design and Cost Calculations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

16.3 Application to Forest Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

16.3.1 General Information and Assumptions Made . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

16.3.2 Process Design and Cost Calculations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

16.4 Land Application at Reclamation Sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

16.4.1 General Information and Assumptions Made . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

16.4.2 Process Design and Cost Calculations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

16.5 Transportation of Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

16.5.1 Truck Hauling of Liquid Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

16.5.2 Truck Hauling of Dewatered Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

16.5.3 Long-Distance Pipeline Transport of Liquid Sewage Sludge . . . . . . . . . . . . . . . . . 217

16.6 Example of Preliminary Cost Estimation for Agricultural Land Application to

Cropland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

16.6.1 Process Design and Cost Calculations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

16.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Appendix A Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

Appendix B Federal Sewage Sludge Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

Appendix C Permit Application Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

Appendix D Conversion Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

Contents

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xii
Figures

Figure Page

1-1 Overview of the Part 503 rule’s land application requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1-2 Suggested sequence for manual use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4-1 Generation, treatment, use, and disposal of sewage sludge and domestic septage . . . . . . . . . . . . . . . 28

5-1 Simplified planning steps for a sewage sludge land application system . . . . . . . . . . . . . . . . . . . . . . . . 40

5-2 Institutional framework. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

5-3 Planning, site selection, and land application practice selection sequence . . . . . . . . . . . . . . . . . . . . . . 51

5-4 General area map with concentric rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5-5 General soil map showing area selected for sewage sludge land application . . . . . . . . . . . . . . . . . . . . 54

5-6 Detailed soil survey map of potential site for sewage sludge land application . . . . . . . . . . . . . . . . . . . . 56

7-1 Determining mineralized PAN from previous sludge applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

7-2 Determining agronomic N rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

7-3 Worksheet 1 calculations to determine residual N credits for previous sewage sludge applications . . . 85

7-4 Calculation of the agronomic N rate for the wheat field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

7-5 Calculation of the agronomic N rate for the corn field. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

11-1 Part 503 pathogen reduction Alternative 1 for domestic septage (without additional treatment) 

applied to agricultural land, forests, or reclamation sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

11-2 Part 503 pathogen reduction Alternative 2 for domestic septage (with pH treatment) applied to 

agricultural land, forests, or reclamation sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

11-3 Part 503 vector attraction reduction options for domestic septage applied to agricultural land, 

forests, or reclamation sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

11-4 Certification of pathogen reduction and vector attraction requirements . . . . . . . . . . . . . . . . . . . . . . . . 133

11-5 Part 503 5-year recordkeeping requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

11-6 Procedure for lime-stabilizing domestic septage within the pumper truck . . . . . . . . . . . . . . . . . . . . . . 136

11-7 Subsurface soil injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

14-1 Examples of sewage sludge transportation modes to land application sites . . . . . . . . . . . . . . . . . . . . 158

14-2a A 6,500-gallon liquid sludge tank truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

14-2b A 3,300-gallon liquid sludge tank truck with 2,000-gallon pup trailer . . . . . . . . . . . . . . . . . . . . . . . . . . 158

14-2c A 25-cubic-yard dewatered sludge haul truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

14-2d A 12-cubic-yard dewatered sludge spreader vehicle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

14-3 Hydraulic characteristics of sludge solids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

14-4 Storage days required as estimated from the use of the EPA-1 computer program for 

wastewater-to-land systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

14-5 Example of mass flow diagram using cumulative generation and cumulative sludge 

application to estimate storage requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

14-6 Splash plates on back of tanker truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

14-7 Slotted T-bar on back of tanker truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

14-8 Tank truck with side spray nozzle for liquid sludge surface application . . . . . . . . . . . . . . . . . . . . . . . . 172

xiii
14-9 Tank truck with liquid sludge tillage injectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

14-10 Tank truck with liquid sludge grassland injectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

14-11 Tractor-pulled liquid sludge subsurface injection unit connected to delivery hose . . . . . . . . . . . . . . . . 174

14-12a Tank wagon with sweep shovel injectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

14-12b Sweep shovel injectors with covering spoons mounted on tank wagon . . . . . . . . . . . . . . . . . . . . . . . . 175

14-13 Center pivot spray application system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

14-14 Traveling gun sludge sprayer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

14-15 Diagram of liquid sludge spreading system in forest land utilizing temporary storage ponds . . . . . . . 176

14-16 A 7.2-cubic-yard dewatered sludge spreader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

14-17 Large dewatered sludge spreader. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

14-18 Example of a disk tiller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

14-19 Example of a disk plow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

15-1 Sludge Management Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

15-2 Restrictions for the harvesting of crops and turf, grazing of animals, and public access on sites 

where Class B biosolids are applied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

15-3 Examples of crops impacted by site restrictions for Class B sewage sludge . . . . . . . . . . . . . . . . . . . . 182

15-4 Required records for preparers of sewage sludge to document sampling and analysis . . . . . . . . . . . 187

15-5 Certification statement required for recordkeeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

15-6 Pathogen reduction alternative 3—analysis and operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

15-7 Notice and necessary information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

Figures

Figure Page

xiv
Tables

Table Page

1-1 Quantity of Sewage Sludge Generated Annually by Use or Disposal Practice . . . . . . . . . . . . . . . . . . . . 1

2-1 Summary of Typical Characteristics of Sewage Sludge Land Application Practices . . . . . . . . . . . . . . . . 6

3-1 Types of Sludge, Septage, and Other Wastewater Solids Excluded From Coverage Under Part 503 . 12

3-2 Definitions of Terms Under the Part 503 Rule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3-3 Who Must Apply for a Permit?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3-4 Part 503 Land Application Pollutant Limits for Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3-5 Part 503 Land Application Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3-6 Summary of Class A and Class B Pathogen Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3-7 Pathogen Requirements for All Class A Alternatives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3-8 The Four Time-Temperature Regimes for Pathogen Reduction Under Class A, Alternative 1 . . . . . . . . 16

3-9 Processes To Further Reduce Pathogens Listed in the Part 503 Rule. . . . . . . . . . . . . . . . . . . . . . . . . . 17

3-10 A Partial List of Processes Recommended as Equivalent to PFRP Under Part 257 . . . . . . . . . . . . . . . 18

3-11 Restrictions for the Harvesting of Crops and Turf, Grazing of Animals, and Public Access on Sites 

Where Class B Sewage Sludge is Land Applied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3-12 Processes to Significantly Reduce Pathogens (PSRPs) Listed in Part 503 . . . . . . . . . . . . . . . . . . . . . . 19

3-13 Selected Processes Recommended as Equivalent to PSRP Under Part 2571 . . . . . . . . . . . . . . . . . . . 19

3-14 Summary of Vector Attraction Reduction Requirements for Land Application of Sewage Sludge 

Under Part 503 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3-15 Frequency of Monitoring for Pollutants, Pathogen Densities, and Vector Attraction Reduction . . . . . . . 23

3-16 Summary of Part 503 Requirements for Different Types of Sewage Sludge . . . . . . . . . . . . . . . . . . . . . 23

3-17 Part 503 Land Application General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3-18 Procedure to Determine the Annual Whole Sludge Application Rate for Sewage Sludge Sold or 

Given Away in a Bag or Other Container for Application to Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4-1 Effects of Sewage Sludge Treatment Processes on Land Application Practices . . . . . . . . . . . . . . . . . 30

4-2 Principal Pathogens of Concern in Municipal Wastewater and Sewage Sludge . . . . . . . . . . . . . . . . . . 31

4-3 Typical Pathogen Levels in Unstabilized and Anaerobically Digested Liquid Sludges . . . . . . . . . . . . . 31

4-4 Nutrient Levels Identified in Sewage Sludge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4-5 Mean Concentrations of Metals in Sewage Sludge Compared to Part 503 

Ceiling Concentration Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4-6 Analytical Classification and Limits for TCLP Constituents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4-7 Chemical and Physical Characteristics of Domestic Septage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4-8 Nutrient Levels in Sewage Sludge From Different Treatment Processes . . . . . . . . . . . . . . . . . . . . . . . . 36

5-1 Preliminary Estimates of Sewage Sludge Applications (Dry Weight) for Different Types of Land . . . . . 43

5-2 Sewage Sludge Solids Content and Handling Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5-3 Transport Modes for Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5-4 Auxiliary Facilities for Sewage Sludge Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

xv
5-5 Evaluation of Sewage Sludge Transport Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

5-6 Suggested Provisions of Contracts Between Sewage Sludge Preparer, Sludge Applier, 

and Private Landowners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

5-7 Potentially Unsuitable Areas for Sewage Sludge Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

5-8 Recommended Slope Limitations for Land Application of Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . 47

5-9 Soil Limitations for Sewage Sludge Application to Agricultural Land at Nitrogen Fertilizer

Rates in Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5-10 Recommended Depth to Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5-11 Potential Impacts of Climatic Regions on Land Application of Sewage Sludge) . . . . . . . . . . . . . . . . . . 49

5-12 Example Design Features Checklist/Comparison of Candidate Land Application Practices . . . . . . . . . 52

5-13 Relative Ranking for Forest Sites for Sewage Sludge Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5-14 Cost Factors To Be Considered During Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5-15 Ranking of Soil Types for Sewage Sludge Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6-1 Basic Site-Specific Information Needed for Land Application of Sewage Sludge. . . . . . . . . . . . . . . . . . 57

6-2 Sample Form for Preliminary Field Site Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6-3 Types of Data Available on SCS Soil Series Description and Interpretation Sheets . . . . . . . . . . . . . . . 59

7-1 Summary of Research on Sewage Sludge Application to Rangeland . . . . . . . . . . . . . . . . . . . . . . . . . . 66

7-2 General Guide to Months Available for Sewage Sludge Application for Different Crops in 

North Central States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

7-3 Representative Fertilizer Recommendations for Corn and Grain Sorghum in the Midwest . . . . . . . . . . 70

7-4 Representative Fertilizer Recommendations for Soybeans in the Midwest . . . . . . . . . . . . . . . . . . . . . . 70

7-5 Representative Fertilizer Recommendations for Small Grains in the Midwest . . . . . . . . . . . . . . . . . . . . 71

7-6 Representative Fertilizer Recommendations for Forages in the Midwest. . . . . . . . . . . . . . . . . . . . . . . . 71

7-7 Estimated Mineralization Rates (Kmin) for Different Sewage Sludges . . . . . . . . . . . . . . . . . . . . . . . . . . 72

7-8 Volatilization Losses of NH4-N as NH3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

7-9 Part 503 Cumulative Pollutant Loading Rate (CLPR) Limits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

7-10 Amounts of Pollutants Added by Sewage Sludge in Design Example . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8-1 Sewage Sludge Application to Recently Cleared Forest Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8-2 Sewage Sludge Application to Young Forest Plantations (Over 2 Years Old) . . . . . . . . . . . . . . . . . . . . 98

8-3 Sewage Sludge Application to Closed Established Forest (Over 10 Years Old) . . . . . . . . . . . . . . . . . . 98

8-4 Comparison of Different Application Systems for Forest Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8-5 Monthly Application Schedule for a Design in the Pacific Northwest . . . . . . . . . . . . . . . . . . . . . . . . . . 100

8-6 Estimated Annual Nitrogen Removal by Forest Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

8-7 Ranges of Values and Suggested Design Values for Nitrogen Transformations and 

Losses From Sewage Sludge Applied to Forest Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

8-8 Example First-year Application Rate for Sewage Sludge Based on Available Nitrogen 

 for Two Different Types of Douglas-fir Stands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

8-9 N Requirements for Sewage Sludge Application to Hybrid Poplar and Established Douglas-fir

Plantations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

8-10 Sewage Sludge Application Rates to Meet N Requirements at Forest Sites . . . . . . . . . . . . . . . . . . . . 106

8-11 Maximum Annual Sewage Sludge Application Based on N Requirements. . . . . . . . . . . . . . . . . . . . . . 106

Tables

Table Page

xvi
9-1 Hectares Under Permit for Surface, Underground, and Other Mining Operations 

From 1977 to 1986 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

9-2 Number of Hectares Reclaimed With Bonds Released During 1977 to 1986 . . . . . . . . . . . . . . . . . . . 109

9-3 Recent Land Reclamation Projects With Municipal Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

9-4 Humid Eastern Region Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

9-5 Drier Mid-West and Western Region Vegetation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

9-6 Western Great Lakes Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

9-7 Northern and Central Prairies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

9-8 Northern Great Plains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

9-9 Southern Great Plains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

9-10 Southern Plains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

9-11 Southern Plateaus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

9-12 Intermountain Desertic Basins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

9-13 Desert Southwest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

9-14 California Valleys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

9-15 Some Sucessful Plant Species and Species Mixtures Used in Various Sludge 

Reclamation Projects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

10-1 Percent of POTWs Selling Sewage Sludge and Mean Price of Sewage Sludge Sold. . . . . . . . . . . . . 127

11-1 Characteristics of Domestic Septage: Conventional Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

11-2 Characteristics of Domestic Septage: Metals and Organics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

11-3 Typical Crop Nitrogen Requirements and Corresponding Domestic Septage Application Rates . . . . . 131

11-4 Summary of Domestic Septage Stabilization Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

11-5 Summary of Land Application Methods for Domestic Septage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

12-1 Relative Effectiveness of Public Participation Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

12-2 Potential Advisory Committee Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

13-1 Monitoring Considerations for Part 503 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

13-2 Sampling Points for Sewage Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

13-3 Sewage Sludge Sample Containers, Preservation, and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

13-4 Analytical Methods for Sewage Sludge Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

13-5 Potential Soil Surface Layer and Subsurface Parameters of Interest. . . . . . . . . . . . . . . . . . . . . . . . . . 152

13-6 Suggested Procedures for Sampling Diagnostic Tissue of Crops. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

14-1 Truck Operation Summary, Liquid Sludge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

14-2 Truck Operation Summary, Dewatered Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

14-3 Projected Monthly Sludge Distribution for Agricultural Sludge Utilization Program, 

Madison, Wisconsin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

14-4 Use of Sewage Sludge Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

14-5 Surface Application Methods for Liquid Sewage Sludge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

14-6 Subsurface Application Methods for Liquid Sewage Sludge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

14-7 Methods and Equipment for Application of Dewatered Semisolid and Solid Sludges . . . . . . . . . . . . . 176

15-1 Part 503 Recordkeeping and Reporting Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

15-2 Recordkeeping Recommendations for Class A Pathogen Reduction Alternatives . . . . . . . . . . . . . . . . 188

Tables

Table Page

xvii
15-3 Recordkeeping Requirements for Class B Pathogen Reduction Alternatives. . . . . . . . . . . . . . . . . . . . 190

16-1 Typical Days Per Year of Food Chain Crop Sludge Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

16-2 Capacity and Number of Onsite Mobile Sludge Application Vehicles Required . . . . . . . . . . . . . . . . . . 200

16-3 Vehicle Load, Unload, and Onsite Travel Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

16-4 Vehicle Sludge Handling Capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

16-5 Gallons of Fuel Per Hour for Various Capacity Sludge Application Vehicles . . . . . . . . . . . . . . . . . . . . 201

16-6 Cost of Onsite Mobile Sludge Application Vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

16-7 Hourly Maintenance Cost for Various Capacities of Sludge Application Vehicles. . . . . . . . . . . . . . . . . 202

16-8 Capacity and Number of Onsite Mobile Sludge Application Vehicles Required . . . . . . . . . . . . . . . . . . 204

16-9 Vehicle Load, Unload, and Onsite Travel Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

16-10 Vehicle Sludge Handling Capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

16-11 Gallons of Fuel Per Hour for Various Capacity Sludge Application Vehicles . . . . . . . . . . . . . . . . . . . . 205

16-12 Cost of On-Site Mobile Sludge Application Vehicles (1994) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

16-13 Hourly Maintenance Cost for Various Capacities of Forest Land Sludge Application Vehicles . . . . . . 207

16-14 Typical Truck Unloading Time as a Function of Type of Land Application Used. . . . . . . . . . . . . . . . . . 211

16-15 Typical Days Per Year of Sludge Hauling as a Function of Types of Application Used and 

Geographical Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

16-16 Number of Vehicles and Capacity of Each Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

16-17 Fuel Use Capacities for Different Sized Trucks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

16-18 Cost of Tanker Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

16-19 Loading Area Costs Based on Sludge Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

16-20 Vehicle Maintenance Cost Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

16-21 Capacity and Number of Haul Vehicles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

16-22 Fuel Usage Values for Different Sized Trucks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

16-23 Costs for Different Sized Trucks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

16-24 Loading Area Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

16-25 Vehicle Maintenance Cost Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

16-26 Factors for Various Sludge Concentrations and Two Types of Sludge . . . . . . . . . . . . . . . . . . . . . . . . . 217

16-27 Head Available from Each Pumping Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

16-28 Annual Labor Per Pump Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

16-29 Pipeline Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

16-30 Annual Cost of Pumping Station Parts and Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

Tables

Table Page

xviii
Acknowledgments

Three groups of participants were involved in the preparation of this manual: (1) the writers, (2) the

technical directors, and (3) the technical reviewers. (Note: This document was originally published

by EPA in 1983; this edition represents a significantly updated revision.) The contractor for this

project was Eastern Research Group, Inc. (ERG), Lexington, Massachusetts, with senior ERG staff

serving as primary writers. Contributing writers provided key information on land application at forest

sites and agricultural sites. The technical advisor was an environmental engineering consultant with

expertise in sewage sludge land application systems, who provided invaluable technical knowledge

throughout the project. Technical direction was provided by U.S. Environmental Protection Agency

(EPA) personnel from the Center for Environmental Research Information (CERI) in Cincinnati,

Ohio, and the Office of Water in Washington, DC. The technical reviewers were experts in sewage

sludge land application, and included university professors/researchers, consultants, and government officials. Each reviewer provided a significant critique of the manual. The people involved in

this project are listed below. 

Manual Preparation

Eastern Research Group, Inc. (ERG)

Writers: Linda Stein, ERG

Russell Boulding, ERG

Jenny Helmick, ERG

Paula Murphy, ERG

Contributing 

Writers: Charles Henry, University of Washington

Lee Jacobs, Michigan State University

Technical Advisor: Sherwood Reed, Environmental Engineering Consultants

Technical Direction

Project Director: James E. Smith, CERI, EPA, Cincinnati, OH

Technical Director: Robert Southworth, Office of Water, EPA, Washington, DC

Technical Review:

William Sopper, Pennsylvania State University, State College, PA

Robert Brobst, U.S. EPA Region VIII, Denver, CO

Robert Southworth, Office of Water, EPA, Washington, DC

Lee Jacobs, Michigan State University, East Lansing, MI

Charles Henry, University of Washington, Eatonville, WA

Ronald Crites, Nolte and Associates, Inc., Sacramento, CA 

xix
Chapter 1

Introduction

1.1 Overview

Land application of sewage sludge1 generated by domestic sewage treatment is performed in an environmentally

safe and cost-effective manner in many communities.

Land application involves taking advantage of the fertilizing

and soil conditioning properties of sewage sludge by

spreading the sewage sludge on the soil surface, incorporating or injecting the sewage sludge into soil, or spraying

the sewage sludge. Because sewage sludge disposal

practices (e.g., landfilling) are becoming less available and

more costly, and because of the increasing desire to beneficially reuse waste residuals whenever possible, land application is increasingly chosen as a sewage sludge use

or disposal practice.

Approximately 33 percent of the 5.4 million dry metric

tons of sewage sludge generated annually in the United

States at publicly owned treatment works (POTWs) is

land applied, as shown in Table 1-1. Of the sewage

sludge that is land applied, approximately 67 percent is

land applied on agricultural lands, 3 percent on forest

lands, approximately 9 percent on reclamation sites,

and 9 percent on public contact sites; 12 percent is sold

or given away in a bag or other container for application

to the land (Federal Register, Vol. 58, No. 32, February

19, 1993). In addition, approximately 8.6 billion gallons

of domestic septage is generated annually.

Land application of sewage sludge has been practiced

in many countries for centuries so that the nutrients

(e.g., nitrogen, phosphorus) and organic matter in sewage sludge can be beneficially used to grow crops or

other vegetation. Over the years, land application has

been increasingly managed to protect human health

and the environment from various potentially harmful

constituents typically found in sewage sludge, such

as bacteria, viruses, and other pathogens; metals

(e.g., cadmium and lead); toxic organic chemicals (e.g.,

PCBs); and nutrients (e.g., nitrogen as nitrate). Management of the land application of sewage sludge has included regulatory measures; voluntary and mandatory

pretreatment of wastewater and/or sludge by industry to

improve quality (e.g., lower pollutant levels); and use of

good management practices at land application sites

(e.g., buffer zones, slope restrictions).

1.2 Sewage Sludge Regulations

In 1993, the U.S. Environmental Protection Agency

(EPA) promulgated 40 CFR Part 503 to address the

Clean Water Act’s (CWA) requirement that EPA develop

a regulation for the use or disposal of sewage sludge.

The CWA required that this regulation protect public

health and the environment from any reasonably anticipated adverse effects of pollutants in sewage sludge.

The elements of the Part 503 land application standard

are illustrated in Figure 1-1. The pollutant limits in the

Part 503 rule were based on in-depth risk assessments

1

 The term “biosolids” has recently gained popularity as a synonym

for sewage sludge because it perhaps fosters “reuse” potential better than the term “sewage sludge.” While this premise may be true,

this manual does not use the term “biosolids” because the term is

not defined consistently at this time and because the federal Part

503 regulation uses the term “sewage sludge.”

Table 1-1. Quantity of Sewage Sludge Generated Annually by

Use or Disposal Practice (Federal Register,

February 19, 1993)

POTWs Using a

Use/Disposal

Practice

Quantity of

Sewage Sludge

Used or Disposeda

Use/Disposal

Practice Number

Percent 

of

POTWs

Quantity

(1,000

dmt)

Percent 

of

Sewage

Sludge

Land application 4,657 34.6 1,785.3 33.3

Incineration 381 2.8 864.7 16.1

Co-disposal: Landfill 2,991 22.2 1,818.7 33.9

Surface disposal 1,351 10.0 553.7 10.3

Unknown:

 Ocean disposalb

 Other

 Transfer

 133

3,920

 25

 1.0

29.1

 0.2

 335.5

 0 

N/A

 6.3

 0.0

 N/A 

All POTWs 13,458 100.0 5,357.2 100.0

a

 Numbers may not add up to 100 percent because of rounding.

b

 The National Sewage Sludge Survey, on which these figures are

based, was conducted before the Ocean Dumping Ban Act of 1988,

which generally prohibited the dumping of sewage sludge into the

ocean after December 31, 1991. Ocean dumping of sewage sludge

ended in June 1992.

1
that investigated the effects on human health and the

environment of using or disposing sewage sludge. The

pollutant limits and management practices in Part 503

protect human health and the environment, as required

by the CWA. Another key component of the rule is

the operational standard that requires reduction of

pathogens (i.e., disease-causing organisms) and of vector attraction (e.g., insects, rodents) using specified operational processes (e.g., treatment), microbiological

monitoring, and physical barriers (e.g., injection or incorporation) for sewage sludge to achieve this reduction.

This operational standard, in the judgement of EPA, protects public health and the environment from pathogens

and vectors. Other parts of the rule (i.e., general requirements, frequency of monitoring, recordkeeping, and reporting requirements) make the rule self-implementing.

Research has shown that most sewage sludge currently

generated in the United States meets the minimum

pollutant limits and pathogen reduction requirements set

forth in Part 503, and that some sewage sludge already

meets the most stringent Part 503 pollutant limits and

pathogen and vector attraction reduction requirements.

This manual refers to the Part 503 regulation throughout

the document as it relates to the specific topic being

discussed (e.g., site selection, design). In addition, this

manual provides a summary of the Part 503 land application requirements (Chapter 3).

State agencies may have their own rules governing the

use or disposal of sewage sludge or domestic septage.

If this is the case, or if a state has not yet adopted

the federal rule, the generator or preparer of sewage

sludge destined for land application will have to follow

the most restrictive portions of both the federal and state

rules. Users or disposers of sewage sludge or domestic

septage are strongly encouraged to check with the appropriate state sewage sludge coordinator to obtain

information on specific and the most up-to-date state

requirements.

1.3 Objectives of Manual

The information in this manual is intended for use by

municipal wastewater treatment and sewage sludge

management authorities, project planners and designers, regional, state, and local governments concerned

with permitting and enforcement of federal sewage

sludge regulations, and consultants in relevant disciplines such as engineering, soil science, and agronomy.

The manual is intended to provide general guidance and

basic information on the planning, design, and operation

of sewage sludge land application projects for one or

more of the following design practices:

• Agricultural land application (crop production, improvement of pasture and rangeland).

• Forest land application (increased tree growth).

• Land application at reclamation sites (mine spoils,

construction sites, gravel pits).

• Land application at public contact sites (such as

parks and golf courses), lawns, and home gardens.

This manual reflects state-of-the art design information

for the land application of sewage sludge. Other EPA

manuals that can serve as useful supplements to this

guide include:

• Environmental Regulations and Technology: Control

of Pathogens and Vector Attraction in Sewage

Sludge. 1992. Office of Research and Development.

EPA/625/R-92/013.

• Preparing Sewage Sludge For Land Application Or

Surface Disposal: A Guide for Preparers of Sewage

Sludge on the Monitoring, Record Keeping, and Reporting Requirements of the Federal Standards for

General Requirements

Recordkeeping

Pollutant Limits

Operational Standards

Reporting

Management


Practices

Frequency of


Monitoring

Pathogen


and Vector


Attraction


Reduction

Sewage


Sludge

Figure 1-1. Overview of the Part 503 rule’s land application requirements.

2
the Use or Disposal of Sewage Sludge, 40 CFR Part

503. 1993. Office of Water. EPA 831 B-93-002.

• A Plain English Guide to the EPA Part 503 Biosolids

Rule. 1994. Office of Wastewater Management.

EPA/832/R-93/003.

• Domestic Septage Regulatory Guidance: A Guide to

the EPA 503 Rule. 1993. Office of Water. EPA 832-

B-92-005.

• Technical Support Document for Land Application of

Sewage Sludge. 1992. Vols. I and II. Office of Water.

EPA 822/R-93-001a. (NTIS No.: PB93-110583 and

PB93-110575).

• Process Design Manual: Sludge Treatment and Disposal. 1979. Office of Research and Development.

EPA/625/1-79/011.

• Process Design Manual for Dewatering Municipal

Wastewater Sludge. 1982. Office of Research and

Development. EPA/625/1-82/014.

References are made throughout this manual to these

and other documents for more detailed information on

specific topics relevant to designing land application

systems. Full citations for all references are provided at

the end of each chapter.

1.4 Scope of Manual

This manual covers both regulatory and non-regulatory

aspects of designing and operating sewage sludge land

application sites. This manual does not discuss the surface disposal of sewage sludge or codisposal of sewage

sludge with municipal solid waste, which is covered in

the Process Design Manual: Surface Disposal of Sewage Sludge and Domestic Septage (EPA, 1995, EPA/

625/R-95/002). This manual also does not discuss incineration of sewage sludge, which is discussed in the

Technical Support Document for Incineration of Sewage

Sludge (EPA, 1992, NTIS PB93-110617). In addition,

discussion of industrial sludge, which is regulated by 40

CFR Part 257, is beyond the scope of this manual.

Figure 1-2 presents a suggested sequence to follow

when using this manual, which may be varied according

to user needs. The manual consists of 16 chapters and

4 appendices. The appendices provide case studies,

regional EPA office information, permit requirements,

and measurement conversions.

3
Domestic

Septage

Guidance

(If Applicable,

Chapter 11)

Public

Participation

Program

(Chapter 12)

Only One Chapter is Used Unless A Combination of Practices is Selected

Detailed Site Evaluation (Chapter 6)

Introduction to Land Application Practices (Chapter 2)

Technical Assessment, Preliminary Planning, and

Selection of Land Application Practices (Chapter 5)

Overview of Sewage Sludge Characteristics (Chapter 4)

Combination

of Two or

More

Practices

Process Design for

Land Application at

Public Contact Sites,

Lawns, and Home

Gardens (Chapter 10)

Process Design

for Forest Land

Application

(Chapter 8)

Monitoring (Chapter 13)

General Site Design Guidance (Chapter 14)

Operation and Management Guidance (Chapter 15)

Cost Guidance (Chapter 16)

Case Studies (Appendix A)

Process Design

for Agricultural

Land Application

(Chapter 7)

Process Design

for Land

Application at

Reclamation Sites

(Chapter 9)

Regulatory Requirements (Part 503, State) (Chapter 3)

Figure 1-2. Suggested sequence for manual use.

4
Chapter 2

Overview of Sewage Sludge Land Application Practices

2.1 Introduction

The sewage sludge land application practices listed in

the previous chapter are not mutually exclusive. For

example, land reclamation may involve the planting of

trees on sewage sludge-amended soil, and two or more

practices (e.g., land application at agricultural and forest

sites) can be used in a single sewage sludge management program. Table 2-1 summarizes the typical characteristics of the sewage sludge land application

practices covered in this manual.

Each of these practices has advantages and disadvantages in terms of the quality and quantities of sewage

sludge that can be utilized and for application site requirements. This chapter provides an overview of the

land application practices and highlights their advantages and disadvantages. Each practice is then discussed in greater detail in the subsequent design

chapters. The design chapters present the criteria and

limitations that establish sewage sludge application

rates in detail.

2.2 Application to Agricultural Lands

2.2.1 Purpose and Definition

Agricultural land application of sewage sludge is practiced in nearly every state, and is especially common in

Colorado, New Jersey, Pennsylvania, Ohio, Illinois,

Michigan, Missouri, Wisconsin, Oregon, and Minnesota.

Hundreds of communities, both large and small, have

developed successful agricultural land application programs. These programs benefit the municipality generating the sewage sludge by providing an ongoing,

environmentally acceptable, and cost-effective means

of managing sewage sludge; the participating farmer

also benefits by receiving the nutrients in sewage sludge

for crop production, generally at a lower cost than conventional fertilizers.

Sewage sludge applied to agricultural land must be

applied at a rate that is equal to or less than the “agronomic rate,” defined in Part 503 as the rate designed to

provide the amount of nitrogen needed by the crop or

vegetation while minimizing the amount of nitrogen in

the sewage sludge that will pass below the root zone of

the crop or vegetation to the ground water. The amount

of available N (or P) applied to the site is based on that

required by the crop. This amount of N would otherwise

be applied to the site as commercial fertilizer by the

farmer. By limiting N loadings to fertilizer recommendations, the impact on ground water should be no greater

than in agricultural operations using commercial fertilizers or manure; ground-water impacts may even be less

because of Part 503’s agronomic rate requirement.

Chapter 7 of this manual provides details of agronomic

rate calculations for agricultural sites.

2.2.2 Advantages of Agricultural Land

Application

Sewage sludge contains several plant macronutrients,

principally N and P, and in most cases, varying amounts

of micronutrients such as boron (B), copper (Cu), iron

(Fe), manganese (Mn), molybdenum (Mo), and zinc

(Zn). The exact ratio of these nutrients will not be that of

a well-balanced formulated fertilizer; but the nutrients in

sewage sludge can be combined with nutrients from

other fertilizers to provide the proper amounts of nutrients needed for crop production.

Sewage sludge can also be a valuable soil conditioner.

The addition of organic materials like sewage sludge to

a fine-textured clay soil can help make the soil more

friable and can increase the amount of pore space

available for root growth and the entry of water and air

into the soil. In coarse-textured sandy soils, organic

residues like sewage sludge can increase the waterholding capacity of the soil and provide chemical sites

for nutrient exchange and adsorption. In some regions

of the country, the water added to the soil during sewage

sludge application also is a valuable resource.

The treatment works generating the sewage sludge can

benefit because in many cases agricultural land application is less expensive than alternative methods of

sewage sludge use or disposal. The general public may

benefit from cost savings resulting from agricultural land

application of sewage sludge, and the recycling of nutrients is attractive to citizens concerned with the environment and resource conservation.

5
Table 2-1. Summary of Typical Characteristics of Sewage Sludge Land Application Practices

Characteristics

Agricultural Land

Applicationa Forest Land

Application

Land Application at

Reclamation Sites

Application to Public

Contact Sites, Lawns,

and Home Gardens

Application rates Varies; normal range in

dry weight of 2 to 70

t/ha/yr (1 to 30 T/ac/yr)

depending on type of

crops, sewage sludge

characteristics, etc.

Typical rate is 10 t/ha/yr

(5 T/ac/yr).

Varies; normal range in

dry weight of 10 to 220

t/ha/yr (4 to 100 T/ac/yr)

depending on soil, tree

species, sewage sludge

quality, etc. Typical rate

is about 18 t/ha/yr (8

T/ac/yr).b

Varies; normal range in

dry weight of 7 to 450

t/ha/yr (3 to 200

T/ac/yr). Typical rate is

112 t/ha/yr (50 T/ac/yr).

Usually a one-time

application.

Varies depending on

end use (e.g., crops,

turf). Typical rate is 18

t/ha/yr (8 T/ac/yr).

Application frequency Typically repeated

annually, usually

scheduled between

harvesting and planting.

Scheduling can be

complex with large

quantities of sludge.

Usually applied annually

or at 3- to 5-year

intervals.

Usually a one-time

application.

Varies depending on

end use.

Ownership of

application site(s)

Usually privately owned

land. Conditions of

application often

covered by a contract

between farmer(s) and

municipality.

Usually owned by

private tree-growing firm

or governmental agency

at state/federal level.

Usually owned by

mining firm or

governmental agency at

state/federal level.

Usually privately owned;

some public contact

sites (e.g., parks) may

be owned by a

governmental agency.

Useful life of application

site(s)

Unlimited for sludge

meeting Part 503

pollutant concentration

limits (PCLs, see

Chapter 3); limited by

accumulated metal

loadings from total

sludge applied when

sludge does not meet

PCLs—typically 20-100

or more years.b

Usually limited by

accumulated metal

loadings in total sewage

sludge applied. With

most sewage sludge, a

useful life of 20 to 55

years or more is typical.b

Usually a one-time

application that helps

revegetate site.

Cumulative pollutant

limits may not be

reached for 13 to 50 or

more years.b

Varies, possibly 32 or

more years.b

Sewage sludge

transport complexity

and cost

Can be expensive if

farms are numerous

and long transportation

distances are involved.

Depends on distance to

forest lands and roads

within site.

Depends on distance to

disturbed lands.

May include conveying

sewage sludge from

wastewater treatment

plant to processing

center, transport of

bulking materials for

composting, and

distribution of the

finished sewage sludge.

Sewage sludge

scheduling

Scheduling can be

difficult, because

applications must work

around planting/

harvesting activities and

poor weather conditions.

Scheduling affected by

climate and maturity of

trees.

Scheduling affected by

climate and availability

of new sites.

Varies depending on

end use.

Application constraints Usually none when

appropriate application

vehicles are used. May

be limited by cropping

pattern and Part 503

agronomic rate

management practice

requirement.

Can be difficult if limited

access roads and

uneven terrain. May

involve specially

designed application

equipment. May be

limited by Part 503

agronomic rate

management practice

requirement.

Usually none, but may

be complicated by

irregular terrain

common at disturbed

sites.

None; similar to surface

application of solid or

semisolid fertilizers,

lime, or animal manure.

Sludge nutrients

beneficially recycled

Yes. Reduces

commercial fertilizer use.

Yes. Reduces or

eliminates commercial

fertilizer use.

Yes. Reduces or

eliminates commercial

fertilizer use.

Yes. Reduces

commercial fertilizer use.

Potential benefits to

existing soil condition

Depends on existing

soil characteristics and

quantity of sludge used.

Depends on existing

soil characteristics.

Yes. Allows soil to

support vegetation and

retards erosion.

Depends on existing

soil characteristics and

quantity of sludge used.

6
A major advantage of agricultural land application is that

usually the treatment works does not have to purchase

land. The land utilized for sewage sludge application is

kept in production, its value for future uses is not impaired, and it remains on the tax rolls. Finally, agricultural land application usually takes place in a relatively

rural setting where the application of sewage sludge is

similar to conventional farming operations, such as

spreading animal manure, and is not likely to become a

public nuisance if properly managed.

2.2.3 Limitations of Agricultural Land

Application

Sewage sludge application rates for agricultural land

application (dry unit weight of sludge applied per unit of

land area) are usually relatively low. Thus, large land

areas may be needed, requiring the cooperation of

many individual land owners. In addition, sewage sludge

transport, as well as application scheduling that is compatible with agricultural planting, harvesting, and possible adverse climatic conditions, will require careful

management. If the farms accepting sewage sludge

are numerous and widespread, an expensive and complicated sewage sludge distribution system may be

required.

2.3 Application to Forest Lands

2.3.1 Purpose and Definition

Except for certain areas in the Great Plains and the

southwest, forested lands are abundant and well distributed throughout most of the United States. Many treatment works are located in close proximity to forests; in

fact, it is estimated that close to one-third of the land

within standard metropolitan areas is forested. Furthermore, approximately two-thirds of all forest land in the

United States is commercial timberland (Smith and

Evans, 1977). Thus, while currently 3 percent of sewage

sludge that is land applied is applied to forest sites, the

application of sewage sludge to forest soils has the

potential to be a major sewage sludge use practice.

Sewage sludge has been land applied at forest sites in

more than ten states, at least on an experimental, fieldscale level. The most extensive experience with this

practice is in the Pacific Northwest. Seattle, Washington,

and a number of smaller towns apply sewage sludge to

forests on a relatively large scale.

Three categories of forest land may be available for

sewage sludge application:

• Recently cleared land prior to planting

• Newly established plantations (about 3 to 10 years old)

• Established forests

The availability of sites and application considerations

for each type of site listed above (as discussed in Chapter 8) will determine which type of site or combination of

sites is best for a forest land application program.

2.3.2 Advantages of Forest Land Application

Sewage sludge contains nutrients and essential micronutrients often lacking in forest soils. Demonstration

projects have shown greatly accelerated tree growth

resulting from sewage sludge application to both newly

established plantations and established forests. In addition, sewage sludge contains organic matter that can

improve the condition of forest soils by increasing the

permeability of fine-textured clay soil, or by increasing

the water-holding capacity of sandy soils.

Treatment works located near forest lands may benefit

because forest land application may be less expensive

than other methods of sewage sludge use or disposal.

The general public may benefit from cost savings realDramatic improvement

in vegetative growth

response

May improve

production; generally

replaces some

commercial fertilizer

nutrients.

Yes. Projects show

large positive impact.

Yes. Projects show

large positive impact.

Depends on existing

soil conditions and

quantities of plant

nutrients normally

applied.

Existing projects using

this practice

Hundreds of large and

small full-scale projects.

A moderate number of

full-scale and

demonstration projects.

A moderate number of

full-scale and

demonstration projects.

A moderate number of

full-scale and

demonstration projects.

Availability of technical

literature pertaining to

this practice

Extensive. Moderate. Moderate. Moderate.

a

 t = metric tonnes, T = English tons

b

 Estimates of useful site life from EPA’s Technical Support Document for Land Application of Sewage Sludge (U.S. EPA, 1992). Site life may

be longer if sludge is not applied every year.

Table 2-1. Summary of Typical Characteristics of Sewage Sludge Land Application Practices (continued)

Characteristics

Agricultural Land

Applicationa Forest Land

Application

Land Application at

Reclamation Sites

Application to Public

Contact Sites, Lawns,

and Home Gardens

7
ized by the treatment works and commercial tree growers using the sewage sludge, and the recycling of nutrients in sewage sludge is attractive to environmentally

concerned citizens. Because forests are perennial, the

scheduling of sewage sludge applications is not as complex as it may be for agricultural land application programs, for which planting and harvesting cycles must be

considered. A final advantage of forest land application

is that the treatment works may not have to pay for

acquiring land. Sewage sludge application to forest soils

is generally performed either annually or at 3- to 5-year

intervals.

2.3.3 Limitations of Forest Land Application

Because sewage sludge application to forest lands is

not as widely practiced as agricultural application, guidance on this practice is more limited. Chapter 8 provides

information on land application at forest sites. The Natural Resource Conservation Service (formerly the Soil

Conservation Service) and County Land-Grant University Extension agents may be able to assist with program design and implementation.

It may be difficult to control public access to sewage

sludge-amended forest lands. The public is accustomed

to free access to forested areas for recreational purposes and may tend to ignore posted signs, fences, etc.

Public access restrictions required in Part 503 are discussed in Chapter 3. Forest lands generally are considered to have low potential for public exposure regarding

risks associated with the land application of sewage

sludge.

Access into some forest lands may be difficult for conventional sewage sludge application equipment. Terrain

may be uneven and obstructed. Access roads may have

to be built, or specialized sewage sludge application

equipment used or developed.

2.4 Land Application at Reclamation

Sites

2.4.1 Purpose and Definition

The surface mining of coal, exploration for minerals,

generation of mine spoils from underground mines, and

tailings from mining operations have created over 1.5

million ha (3.7 million ac) of drastically disturbed land.

The properties of these drastically disturbed and marginal lands vary considerably from site to site. Their

inability to support vegetation is the result of several

factors:

• Lack of nutrients. The soils have low N, P, K, or

micronutrient levels.

• Physical properties. Stony or sandy materials have

poor water-holding capacity and low cation exchange

capacity (CEC). Clayey soils have poor infiltration,

permeability, and drainage.

• Chemical properties. The pH of mine soils, tailings,

and some drastically disturbed soils range from very

acidic to alkaline. Potentially phytotoxic levels of Cu,

Zn, Fe, and salts may be present.

• Organic matter. Little, if any, organic matter is present.

• Biological properties. Soil biological activity is generally reduced.

• Topography. Many of these lands are characterized

by steep slopes that are subject to excessive erosion.

Historically, reclamation of these lands is accomplished

by grading the surface to slopes that minimize erosion

and facilitate revegetation. In some cases, topsoil is

added. Soil amendments such as lime and fertilizer also

are added, and grass, legumes, or trees are planted.

Although these methods are sometimes successful, numerous failures have occurred, primarily because of the

very poor physical, chemical, or biological properties of

these disturbed lands.

Sewage sludge can be used to return barren land to

productivity or to provide the vegetative cover necessary

for controlling soil erosion. A relatively large amount of

sewage sludge must be applied to a land area (7 to

450 t DW/ha) to provide sufficient organic matter and

nutrients capable of supporting vegetation until a selfsustaining ecosystem can be established. Because of

these typically large, one-time applications of sewage

sludge at reclamation sites, the Part 503 rule allows

sewage sludge application at reclamation sites to exceed agronomic rates for N if approved by the permitting

authority, who may require surface water or groundwater monitoring as a condition for sewage sludge application, if deemed necessary.

Pilot and full-scale demonstration projects have been

undertaken in at least 20 states to study the application

of sewage sludge to reclaimed lands. The results suggest that sewage sludge can be used effectively to

reclaim disturbed sites when the application of sewage

sludge is managed properly. The following factors must

be considered: the degree to which the sewage sludge

is stabilized, sewage sludge application rates, the degree of land slope, and siting issues (e.g., quality of

aquifer, depth to ground water).

Because sewage sludge typically is applied only once

to land reclamation sites, an ongoing program of sewage sludge application to disturbed lands requires that

a planned sequence of additional sites be available for

the life of the program. This objective may be achieved

through arrangements with land owners and mining

firms active in the area or through planned sequential

rehabilitation of existing disturbed land areas. Once a

reclamation site is reclaimed, sewage sludge can be

8
applied to the site in compliance with the requirements

for the type of site it may become (e.g., agricultural or

forest land, or a public contact site). For example, reclaimed areas may be used for crop production using

agronomic rates of sewage sludge application.

2.4.2 Advantages of Land Application at

Reclamation Sites

Land application may be extremely attractive in areas

where disturbed and marginal lands exist because of the

benefit to the treatment works in using or disposing its

sewage sludge and to the environment through reclamation of unsightly, largely useless land areas.

Sewage sludge has several characteristics that makes

it suitable for reclaiming and improving disturbed lands

and marginal soils. One of the most important is the

sewage sludge organic matter which (1) improves soil

physical properties by improving granulation, reducing

plasticity and cohesion, and increasing water-holding

capacity; (2) increases the soil cation exchange capacity; (3) supplies plant nutrients; (4) increases and buffers

soil pH; and (5) enhances the rejuvenation of microorganism populations and activity.

The natural buffering capacity and pH of most sewage

sludge will improve the acidic or moderately alkaline

conditions found in many mine soils. Immobilization of

heavy metals is pH-dependent, so sewage sludge application reduces the potential for acidic, metal-laden

runoff and leachates. Sewage sludge is also desirable

because the nutrients contained in it may substantially

reduce commercial fertilizer needs. Furthermore, sewage sludge helps to increase the number and activity of

soil microorganisms.

The amount of sewage sludge applied in a single application can often be greater for land reclamation than for

agricultural land application, provided that the quantities

applied do not pose a serious risk of future plant phytotoxicity or unacceptable nitrate leaching into a potable

ground water aquifer, and if regulatory agency approval

is granted. In some cases, serious degradation of surface water and ground water may already exist at the

proposed site, and a relatively heavy sewage sludge

addition with subsequent revegetation can be justified

as improving an already bad situation.

The treatment works may not have to purchase land for

reclamation projects. In addition, disturbed or marginal

lands are usually located in rural, relatively remote

areas.

2.4.3 Limitations of Land Application at

Reclamation Sites

Plant species for revegetation at reclamation sites

should be carefully selected for their suitability to local

soil and climate conditions. If crops intended for animal

feed or human consumption are planted, the requirements for agricultural land application of sewage sludge

have to be met.

Reclamation sites, especially old abandoned mining

sites, often have irregular, excessively eroded terrain.

Extensive grading and other site preparation steps may

be necessary to prepare the site for sewage sludge

application. Similarly, disturbed lands often have irregular patterns of soil characteristics. This may cause difficulties in sewage sludge application, revegetation, and

future site monitoring.

2.5 Land Application at Public Contact

Sites, Lawns, and Home Gardens

2.5.1 Purpose and Definition

Approximately 9 percent of sewage sludge that is land

applied annually is used as a soil conditioner or fertilizer

on land having a high potential for public contact. These

public contact sites include public parks, ball fields,

cemeteries, plant nurseries, highway median strips, golf

courses, and airports, among others. Another 12 percent of land applied sewage sludge is sold or given away

in a bag or other container, most likely for application to

public contact sites, lawns, and home gardens. Usually,

sewage sludge that is sold or given away in a bag or

other container is composted, or heat dried (and sometimes formed into pellets). Composted sewage sludge is

dry, practically odorless, and easy to distribute and handle. Bagged or otherwise containerized sewage sludge

that is sold or given away often is used as a substitute

for topsoil and peat on lawns, golf courses, parks, and

in ornamental and vegetable gardens. Yield improvements have been valued at $35 to $50 per dry ton over

other potting media (U.S. EPA, 1993).

There have been two basic approaches to sewage

sludge use in parks and recreational areas: (1) land

reclamation followed by park establishment, and (2) use

of sewage sludge as a substitute for conventional fertilizers in the maintenance of established parkland vegetation. Sewage sludge can supply a portion of the

nutrients required to maintain lawns, flower gardens,

shrubs and trees, golf courses, recreational areas, etc.

2.5.2 Advantages of Land Application at

Public Contact Sites, Lawns, and Home

Gardens

Programs designed to promote sewage sludge land

application to public contact sites, lawns, and home

gardens are particularly advantageous for treatment

works having limited opportunities for other types of land

application (e.g., at forest sites, agricultural land, and

reclamation sites).

9
In some areas of the country, a high demand exists for

bagged sewage sludge applied to public contact sites,

lawns, and home gardens. This is, in part, due to the fact

that sewage sludge often is sold at lower cost than many

commercial fertilizers, or is given away free. In addition,

although the nutrient content of many sewage sludges

is lower than that of commercial fertilizers, sewage

sludge contains organic matter that can release nutrients more slowly, minimizing potential “burning” of

plants (Lue-Hing et al., 1992).

2.5.3 Limitations of Land Application at

Public Contact Sites, Lawns, and Home

Gardens

Many of the strictest requirements of the Part 503 rule,

in particular the pollutant limits for metals and the pathogen requirements, must be met for sewage sludge applied to lawns, home gardens, and public contact sites.

This is because of the high potential for human contact

with the sewage sludge at these sites and because it is

not possible to impose site restrictions when sewage

sludge is sold or given away in a bag or other container

for application to the land. While meeting the pollutant

limits and pathogen requirements will not be difficult for

many sewage sludge preparers, some treatment works

have reported problems in meeting certain of these

requirements, and corrective measures would involve

increased operational costs.

In general, the costs of a program that markets sewage

sludge for use on lawns, home gardens, and public

contact sites may be greater than the costs of direct land

application. Major costs include those for sewage

sludge dewatering, processes to achieve adequate

pathogen and vector attraction reduction, market development, and transportation.

2.6 References

Lue-Hing, C., D.R. Zenz, and R. Kuchenrither, eds. 1992. Municipal

sewage sludge management: Processing, utilization, and disposal. In: Water quality management library, Vol. 4. Lancaster, PA:

Technomic Publishing Company, Inc.

Smith, W., and J. Evans. 1977. Special opportunities and problems

in using forest soils for organic waste application. In: Elliott, L.F.,

and J.F. Stevenson, eds. Soils for management of organic wastes

and wastewaters. Soil Science Society of America, Madison, WI.

U.S. EPA. 1993. Standards for the use or disposal of sewage sludge.

Fed. Reg. 58(32):9259.

10
Chapter 3

Overview of the Part 503 Regulatory Requirements for Land Application of

Sewage Sludge

3.1 General

The federal Part 503 rule (40 CFR Part 503) establishes

requirements for land applying sewage sludge (including domestic septage) to ensure protection of public

health and the environment when sewage sludge is

used for its soil conditioning or fertilizing properties.

Promulgated in 1993, Part 503 covers sewage sludge

sold or given away in bulk, bags, or other containers for

application to agricultural land (e.g., cropland, pastures,

and rangelands), forests, reclamation sites (e.g., mine

spoils, construction sites, and gravel pits), public contact

sites (e.g., parks, plant nurseries), and lawns and home

gardens. The rule’s land application requirements also

pertain to material derived from sewage sludge. Such

materials include sewage sludge that has undergone a

change in quality through treatment (e.g., composting,

drying) or mixing with other materials (e.g., wood chips)

after it leaves the treatment works where it was generated. Part 503 also covers surface disposal and incineration of sewage sludge, which are beyond the scope

of this manual.

This chapter highlights key aspects of the Part 503 rule

as they pertain to land application of sewage sludge,

including general requirements, pollutant limits, management practices, pathogen and vector attraction reduction, frequency of monitoring, recordkeeping, and

reporting, as shown in Chapter 1, Figure 1-1. For a

discussion of Part 503 requirements for the land application of domestic septage, see Chapter 11. More detailed discussions of the rule can be found in other EPA

documents (U.S. EPA, 1992a; 1992b; 1994).

For most types of sewage sludge other than those specifically excluded (see Table 3-1), the requirements in 40

CFR Part 503 supersede those in 40 CFR Part 257—the

previous rule that governed the use or disposal of sewage sludge from 1979 to 1993. Part 503 establishes

minimum standards; when necessary to protect public

health and the environment, the permitting authority

may impose requirements that are more stringent than,

or in addition to, those stipulated in the Part 503 rule.

The rule leaves to the discretion of individual states

whether to administer a more restrictive sewage sludge

use or disposal program than is required by the federal

regulation. A state program may even define sewage

sludge differently than the federal regulation (see Table

3-2). Also, while state officials are encouraged to submit

their sewage sludge programs for review and approval

by EPA, they are not required to do so. A disadvantage

of an unapproved state program for the regulated community is the added complexity of complying with all

applicable federal and state requirements, including the

most restrictive requirements of both the state program

and the federal rule. Both state and federal operating

permits also might be required in a state with a sewage

sludge management program that has not been approved by EPA.

For the most part, the requirements of the Part 503 rule

are implemented through permits issued by EPA or by a

state that administers an EPA-approved sewage sludge

management program (see Table 3-3). But the Part 503

rule is “self-implementing,” meaning that persons who

generate, prepare, or land apply sewage sludge must

comply with the rule even if they are not specifically

required to obtain a permit.

To ensure compliance with the rule, regulatory officials

have the authority to inspect operations, review records,

sample applied sewage sludge, and generally respond

to complaints concerning public health or public nuisances. EPA also is prepared to pursue enforcement

actions when necessary to address violations, whether

willful or the result of negligence. In the absence of a

government enforcement action, private citizens have

standing to pursue civil remedies against a violator under the Clean Water Act.

3.2 Pollutant Limits

Subpart B of the Part 503 rule prohibits the land application of sewage sludge that exceeds pollutant limits

termed ceiling concentrations in the rule for 10 metals,

and places restrictions on the land application of sewage sludge that exceeds additional pollutant limits specified in the rule (pollutant concentrations, cumulative

11
pollutant loading rates [CPLRs], or annual pollutant

loading rates [APLRs]). For one of the regulated metals, molybdenum, only ceiling concentrations apply

while EPA reconsiders the CPLRS, pollutant concentration limits, and APLRs established by the rule. The

different types of pollutant limits included in Part 503

are discussed below and are listed in Table 3-4.

3.2.1 Ceiling Concentration Limits

All sewage sludge applied to land must meet Part 503

ceiling concentration limits for the 10 regulated pollutants.

Ceiling concentration limits are the maximum allowable

concentration of a pollutant in sewage sludge to be land

applied. If the ceiling concentration limit for any one of the

regulated pollutants is exceeded, the sewage sludge cannot be land applied. The ceiling concentration limits were

Table 3-1. Types of Sludge, Septage, and Other Wastewater

Solids Excluded From Coverage Under Part 503

Sludge Type

Applicable Federal

Requirements

Sewage sludge that is hazardous

in accordance with 40 CFR Part

261

40 CFR Parts 261-268

Sewage sludge with a PCB

concentration equal to or greater

than 50 mg/kg total solids (dry

weight basis)

40 CFR Part 761

Grit (e.g., small pebbles and

sand) and screenings (e.g., large

materials such as rags) generated

during preliminary treatment of

sewage sludge

40 CFR Part 257 (if 

land applied)

40 CFR Part 258 (if

placed in a municipal

solid waste landfill)

Commercial septage (e.g., grease

from a grease trap at a

restaurant) and industrial septage

(e.g., liquid or solid material

removed from a septic tank that

receives industrial wastewater)

and mixtures of domestic septage

and commerical or industrial

septage

40 CFR Part 257 (if 

land applied)

40 CFR Part 258 (if

placed in a municipal

solid waste landfill)

Industrial sludge and sewage

sludge generated at an industrial

facility during the treatment of

industrial wastewater with or

without combined domestic

sewage

40 CFR Part 257 (if 

land applied)

40 CFR Part 258 (if

placed in a municipal

solid waste landfill)

Incinerator ash generated during

the firing of sewage sludge in a

sewage sludge incinerator

40 CFR Part 257 (if 

land applied)

40 CFR Part 258 (if

placed in a municipal

solid waste landfill) or 

40 CFR Parts 261-268 

(if hazardous) 

Sewage sludge co-fired in an

incinerator with other wastes

(other than an auxiliary fuel)

40 CFR Parts 60, 61 

Drinking water sludge generated

during the treatment of either

surface water or ground water

used for drinking water

40 CFR Part 257 (if 

land applied)

40 CFR Part 258 (if

placed in a municipal

solid waste landfill)

Treatment of sewage sludge prior

to final use or disposal (e.g.,

processes such as thickening,

dewatering, storage, heat drying)

None (except for

operational parameters

used to meet Part 503

pathogen and vector

attraction reduction

requirements)

Storage of sewage sludge as

defined in Part 503

None

Table 3-2. Definitions of Terms Under the Part 503 Rule

Bulk Sewage Sludge Sewage sludge that is not sold or given

away in a bag or other container for

application to land.

Domestic Septage A liquid or solid material removed from a

septic tank, cesspool, portable toilet, Type

III marine sanitation device, or similar

system that receives only domestic

sewage. Domestic septage does not

include grease-trap pumpings or

commercial/industrial wastes.

Domestic Sewage Waste and wastewater from humans or

household operations that is discharged

to or otherwise enters a treatment works.

Preparer The person who generates sewage

sludge during the treatment of domesitc

sewage in a treatment works, or the

person who derives a material from

sewage sludge.

Scum, Grit, and

Screenings

Scum consists of floatable materials in

wastewater and is regulated by Part 503

if it is subject to one of the Part 503 use

or disposal practices because it is, by

definition, sewage sludge. Grit, which is

regulated under 40 CFR Part 257 when

applied to the land, consists of heavy,

coarse, inert solids (e.g., sand, silt,

gravel, ashes, corn grains, seed, coffee

ground, and bottle caps) associated with

raw wastewater. Screenings, which also

are regulated under Part 257 when

applied to the land, consist of such solids

as rags, sticks, and trash found in the

raw wastewater.

Sewage Sludge A solid, semi-solid, or liquid residue

generated during the treatment of

domestic sewage in a treatment

works. Sewage sludge includes scum

or solids removed in primary,

secondary, or advanced wastewater

treatment processes and any material

derived from sewage sludge (e.g., a

blended sewage sludge/fertilizer

product), but does not include grit and

screening or ash generated by the

firing of sludge in an incinerator. Part

503 considers domestic septage as

sewage sludge and sets separate

requirements for domestic septage

applied to agricultural land, forests, or

reclamation sites.

Treatment Works A federally, publicly, or privately owned

device or system used to treat (including

recycle and reclaim) either domestic

sewage or a combination of domestic

sewage and industrial waste of a liquid

nature.

12
developed to prevent the land application of sewage

sludge containing high concentrations of pollutants.

3.2.2 Pollutant Concentration Limits

Pollutant concentration limits are the most stringent pollutant limits included in Part 503 for land application.

These limits help ensure that the quality of land-applied

sewage sludge remains at least as high as the quality

of sewage sludge at the time the Part 503 rule was

developed. Sewage sludge meeting pollutant concentration limits, as well as certain pathogen and vector

attraction reduction requirements (see Section 3.7.1),

generally is subject to fewer Part 503 requirements than

sewage sludge meeting cumulative pollutant loading

rates (CPLRs) (discussed below).

3.2.3 Cumulative Pollutant Loading Rates

(CPLRs)

A cumulative pollutant loading rate (CPLR) is the maximum amount of a pollutant that can be applied to a site

by all bulk sewage sludge applications made after July

20, 1993. CPLRs pertain only to land application of bulk

sewage sludge, as defined in Part 503. When the maximum CPLR is reached at the application site for any one

of the 10 metals regulated by the Part 503 rule, no

additional sewage sludge subject to the CPLRs can be

applied to the site. If a CPLR is reached at a site, only

sewage sludge that meets the pollutant concentration

limits could be applied to that site.

Table 3-3. Who Must Apply for a Permit?

Treatment Works Treating Domestic Sewage (TWTDS)

Required to Apply for a Permit

• All generators of sewage sludge that is regulated by Part 503

(including all POTWs)

• Industrial facilities that separately treat domestic sewage and

generate sewage sludge that is regulated by Part 503

• All surface disposal site owner/operators

• All sewage sludge incinerator owner/operators

• Any other person designated by the permitting authority as a

TWTDS

TWTDS and Other Persons Not Automatically Required To

Apply for a Permita

• Any person (e.g., individual, corporation, or government entity)

who changes the quality of sewage sludge regulated by Part 503

(e.g., sewage sludge blenders or processers)b

• Sewage sludge land appliers, haulers, persons who store, or

transporters who do not generate or do not change the quality of

the sludge

• Land owners of property on which sewage sludge is applied

• Domestic septage pumpers/haulers/treaters/appliers

• Sewage sludge packagers/baggers (who do not change the

quality of the sewage sludge)

a EPA may request permit applications from these persons when

necessary to protect public health and the environment from reasonably anticipated effects of pollutants that may be present in

sewage sludge. b

 If all the sewage sludge received by a sludge blender or composter

is exceptional quality (EQ) sludge, then no permit will be required

for the person who receives or processes the EQ sludge.

Table 3-4. Part 503 Land Application Pollutant Limits for Sewage Sludge

Pollutant

Ceiling Concentration

Limits (milligrams per

kilogram)a,b

Pollutant Concentration

Limits (milligrams per

kilogram)a,c

Cumulative Pollutant

Loading Rate Limits

(kilograms per hectare)

Annual Pollutant

Loading Rate Limits

(kilograms per hectare

per 365-day period)

Arsenic 75 41 41 2.0

Cadmium 85 39 39 1.9

Chromiumd 3,000 1,200 3,000 150 

Copper 4,300 1,500 1,500 75 

Lead 840 300 300 15 

Mercury 57 17 17 0.85

Molybdenum 75 —d —d —d 

Nickel 420 420 420 21 

Selenium 100 36d 100 5.0

Zinc 7,500 2,800 2,800 140 

Applies to: All sewage sludge that 

is land applied

Bulk sewage sludge and

bagged sewage sludgee Bulk sewage sludge Bagged sewage sludgee

From Part 503 Table 1, Section 503.13 Table 3, Section 503.13 Table 2, Section 503.13 Table 4, Section 503.13

a

 Dry-weight basis.

b

 All sewage sludge samples must meet the ceiling concentrations, at a minimum, to be eligible for land application (instantaneous values).

c

 Monthly average.

d

 EPA is re-examining these limits.

e

 Bagged sewage sludge is sold or given away in a bag or other container for application to the land.

13
3.2.4 Annual Pollutant Loading Rates

(APLRs)

The annual pollutant loading rate (APLR) is the maximum amount of a pollutant that can be applied to a site

within a 12-month period from sewage sludge that is

sold or given away in a bag or other container for

application to land.1

 To meet the APLRs, the pollutant

concentration in sewage sludge, multiplied by the “annual whole sludge application rate,” as determined in

Appendix A of the Part 503 rule, must not cause any of

the APLRs to be exceeded. APLRs rather then CPLRs

are used for sewage sludge sold or given away in a bag

or other container for application to land because controlling cumulative applications of these types of sewage

sludge would not be feasible.

APLRs are based on a 20-year site life, which EPA

considers a conservative estimate because sewage

sludge sold or given away in small quantities will most

likely be applied to lawns, home gardens, or public

contact sites. Sewage sludge is not likely to be applied

to such types of land for longer than 20 years; indeed,

20 consecutive years of application is unlikely (U.S.

EPA, 1992a).

3.2.5 Why Organic Pollutants Were Not

Included in Part 503

The Part 503 regulation does not establish pollutant

limits for any organic pollutants because EPA determined that none of the organics considered for regulation2 pose a public health or environmental risk

from land application of sewage sludge (U.S. EPA,

1992a). EPA used the following criteria to make this

determination:

• The pollutant is banned or restricted in the United

States or is no longer manufactured in the United

States; or

• The pollutant is not present in sewage sludge at significant frequencies of detection, based on data gathered from the 1990 NSSS; or

• The limit for a pollutant from EPA’s exposure assessment is not expected to be exceeded in sewage

sludge that is used or disposed, based on data from

the NSSS.

3.3 Management Practices

As described in Table 3-5, the Part 503 rule specifies

management practices that must be followed when sewage sludge is land applied. Management practices required for bulk sewage sludge meeting Part 503

pollutant concentration limits or cumulative pollutant

loading rates protect water quality and the survival of

threatened or endangered species. For example, bulk

sewage sludge that meets these pollutant limits cannot

be applied to sites that are flooded or frozen in such a

way that the sewage sludge might enter surface waters

or wetlands. Also, any direct or indirect action that

diminishes the likelihood of a threatened or endangered species’ survival by modifying its critical habitat is prohibited. Other Part 503 management practices

are listed in Table 3-5.

1

 “Other containers” are defined in Part 503 as open or closed receptacles, such as buckets, boxes, cartons, or vehicles, with a load

capacity of 1 metric ton or less. 2

 Aldrin/dieldrin, benzene, benzo(a)pyrene, bis(2ethylhexyl)phthalate,

chlordane, DDT (and its derivatives DDD and DDE), dimethyl nitrosamine, heptachlor, hexachlorobenzene, hexachlorobutadiene,

lindane, PCBs, toxaphene, and trichloroethylene.

Table 3-5. Part 503 Land Application Management Practices

For Bulk Sewage Sludgea

Bulk sewage sludge cannot be applied to flooded, frozen, or

snow-covered agricultural land, forests, public contact sites, or

reclamation sites in such a way that the sewage sludge enters a

wetland or other waters of the United States (as defined in 40

CFR Part 122.2), except as provided in a permit issued pursuant

to Section 402 (NPDES permit) or Section 404 (Dredge and Fill

Permit) of the Clean Water Act, as amended.

Bulk sewage sludge cannot be applied to agricultural land, forests,

or reclamation sites that are 10 meters or less from U.S. waters,

unless otherwise specified by the permitting authority.

If applied to agricultural lands, forests, or public contact sites, bulk

sewage sludge must be applied at a rate that is equal to or less

than the agronomic rate for the site. Sewage sludge applied to

reclamation sites may exceed the agronomic rate if allowed by the

permitting authority.

Bulk sewage sludge must not harm or contribute to the harm of a

threatened or endangered species or result in the destruction or

adverse modification of the species’ critical habitat when applied to

the land. Threatened or endangered species and their critical

habitats are listed in Section 4 of the Endangered Species Act.

Critical habitat is defined as any place where a threatened or

endangered species lives and grows during any stage of its life

cycle. Any direct or indirect action (or the result of any direct or

indirect action) in a critical habitat that diminishes the likelihood of

survival and recovery of a listed species is considered destruction

or adverse modification of a critical habitat.

For Sewage Sludge Sold or Given Away in a Bag or Other

Container for Application to the Landa

A label must be affixed to the bag or other container, or an

information sheet must be provided to the person who receives

this type of sewage sludge in another container. At a minimum, the

label or information sheet must contain the following information: 

• the name and address of the person who prepared the sewage

sludge for sale or give-away in a bag or other container;

• a statement that prohibits application of the sewage sludge to the

land except in accordance with the instructions on the label or

information sheet;

• an AWSAR (see Table 3-18) for the sewage sludge that does not

cause the APLR pollutant limits to be exceeded.

a These management practices do not apply if the sewage sludge is

of “exceptional quality," as defined in section 3.7.

14
The preparer of sewage sludge that is sold or given

away in a bag or other container for application to land

must comply with the Part 503 management practice

that requires the preparer to provide application rate

information, as well as other pertinent data, to the land

applier of sewage sludge meeting annual pollutant loading rates (as discussed in Table 3-5 and Section 3.7.4).

3.4 Operational Standards for

Pathogens and Vector Attraction

Reduction

Subpart D of the Part 503 rule describes requirements

for land application of sewage sludge (and domestic

septage, as discussed in Chapter 11) that reduce the

potential for the spread of disease, thus protecting public

health and the environment. The Part 503 Subpart D

requirements cover two characteristics of sewage sludge:

• Pathogens. Part 503 requires the reduction of potential disease-bearing microorganisms called pathogens (such as bacteria and viruses) in sewage sludge.

• Vector Attraction. Part 503 also requires that the potential for sewage sludge to attract vectors (e.g., rodents, birds, insects) that can transport pathogens

away from the land application site be reduced.

Compliance with the Part 503 pathogen and vector attraction reduction requirements, summarized below,

must be demonstrated separately.

3.4.1 Pathogen Reduction Requirements

The Part 503 pathogen reduction requirements for sewage sludge are divided into two categories: Class A and

Class B, as shown in Table 3-6. The implicit goal of the

Class A requirements is to reduce the pathogens in

sewage sludge (including Salmonella sp. bacteria, enteric viruses, and viable helminth ova) to below detectable levels. When this goal is achieved, Class A sewage

sludge can be land applied without any pathogen-related restrictions on the site (see Section 3.7).

The implicit goal of the Class B requirements is to

ensure that pathogens have been reduced to levels that

are unlikely to pose a threat to public health and the

environment under specific use conditions. Site restrictions on the land application of Class B sewage sludge

minimize the potential for human and animal contact

with the sewage sludge until environmental factors have

reduced pathogens to below detectable levels. In addition, to further reduce the likelihood of human contact

with pathogens, Class B sewage sludge cannot be sold

or given away in a bag or other container for land

application. Part 503 Class A and B pathogen reduction

requirements are summarized below; another EPA

document (U.S. EPA, 1992b) provides a detailed discussion of pathogen reduction requirements under Part 503.

3.4.1.1 Class A Pathogen Requirements

Sewage sludge that must meet the Class A pathogen

requirements includes sewage sludge that is sold or

given away in a bag or other container for application to

land and bulk sewage sludge that is applied to a lawn

or home garden. Part 503 Subpart D establishes six

alternatives for demonstrating that sewage sludge

meets Class A pathogen reduction requirements (Table

3-6). The rule requires that the density of fecal coliforms

be less than 1,000 Most Probable Number (MPN) per

gram total solids (dry weight) or that Salmonella sp.

bacteria be less than 3 per 4 grams total solids, as

discussed in Table 3-7.

Table 3-6. Summary of Class A and Class B Pathogen

Alternatives

CLASS A

In addition to meeting the

requirements in one of the six

alternatives listed below, fecal

coliform or Salmonella sp.

bacterial levels must meet

specific densities at the time

of sewage sludge use or

disposal, when prepared for

sale or give-away in a bag or

other container for application

to the land, or when prepared

to meet the requirements in

503.10(b), (c), (e), or (f)

Alternative 1: Thermally

Treated Sewage Sludge 

Use one of four

time-temperature regimes 

Alternative 2: Sewage Sludge

Treated in a High pH-High

Temperature Process

Specifies pH, temperature,

and air-drying requirements

Alternative 3: For Sewage

Sludge Treated in Other

Processes

Demonstrate that the process

can reduce enteric viruses

and viable helminth ova.

Maintain operating conditions

used in the demonstration

Alternative 4: Sewage

Sludge Treated in Unknown

Processes

Demonstration of the process

is unnecessary. Instead, test

for pathogens—Salmonella

sp. bacteria, enteric viruses,

and viable helminth ova—at

the time the sewage sludge is

used or disposed, or is

prepared for sale or

give-away in a bag or other

container for application to 

the land, or when prepared to

meet the requirements in

503.10(b), (c), (e), or (f)

Alternative 5: Use of PFRP

Sewage sludge is treated in

one of the processes to further

reduce pathogens (PFRP)

Alternative 6: Use of a

Process Equivalent to PFRP

Sewage sludge is treated in a

process equivalent to one of

the PFRPs, as determined by

the permitting authority

CLASS B

The requirements in one of

the three alternatives below

must be met in addition to

Class B site restrictions

Alternative 1: Monitoring of

Indicator Organisms

Test for fecal coliform density

as an indicator for all

pathogens at the time of

sewage sludge use or disposal

Alternative 2: Use of PSRP

Sewage sludge is treated in one

of the processes to significantly

reduce pathogens (PSRP)

Alternative 3: Use of

Processes Equivalent to

PSRP

Sewage sludge is treated in a

process equivalent to one of

the PSRPs, as determined by

the permitting authority

Note: Details of each

alternative for meeting the

requirements for Class A and

Class B designations are

provided in Section 3.4.

15
Each of the six alternatives for meeting Class A pathogen reduction requirements includes monitoring requirements to ensure that substantial regrowth of pathogenic

bacteria does not occur after the sewage sludge meets the

pathogen reduction requirements prior to use or disposal.

The timing of Class A pathogen reduction in relation to

vector attraction reduction requirements (see Section

3.4.2) is important when certain vector attraction reduction options are used. Part 503 requires that Class A

pathogen reduction be accomplished before or at the same

time as vector attraction reduction, except when vector

attraction reduction is achieved by alkali addition or drying.

The following discussion summarizes the Part 503 Class

A pathogen reduction alternatives. For a more complete

discussion of these alternatives, see Environmental Regulations and Technology: Control of Pathogens and Vector

Attraction in Sewage Sludge (U.S. EPA, 1992b).

Alternative 1: Thermally Treated Sewage Sludge

This alternative may be used when the pathogen reduction process relies on specific time-temperature regimes

to reduce pathogens (Table 3-8). The approach involves

calculating the heating time necessary at a particular

temperature to reduce a sewage sludge’s pathogen content to below detectable levels. The need to conduct

time-consuming and expensive tests for the presence of

specific pathogens can be avoided with this approach.

The microbiological density portion of the requirement

(i.e., the regrowth requirement) is designed to ensure

that the microbiological reductions expected as a result

of the time-temperature regimes have actually been

attained and that regrowth has not occurred. Equations

for each of the four time-temperature regimes takes into

account the percent of solids in the sewage sludge and

the operating parameters of the treatment process.

Alternative 2: Sewage Sludge Treated in a High

pH-High Temperature Process

This alternative may be used when the pathogen reduction process relies on a particular high temperature-high

pH process that has been demonstrated to be effective

in reducing pathogens to below detectable levels. The

high pH (>12 for more than 72 hours) and high temperature (above 52°C [126°F] for at least 12 hours while pH

is >12) for prolonged periods allow a less stringent timetemperature regime than the requirements under Alternative 1. After the 72-hour period during which the pH

of the sewage sludge is above 12, the sewage sludge

must be air dried to achieve a percent solids content of

greater than 50 percent. As when thermal processing is

used, monitoring for regrowth of pathogenic bacteria (fecal

coliforms or salmonellae) must be conducted (Table 3-7).

Alternative 3: Sewage Sludge Treated in Other

Processes

This alternative applies to sewage sludge treated by

processes that do not meet the process conditions required by Alternatives 1 and 2. Alternative 3 relies on

comprehensive monitoring of fecal coliform or Salmonella sp. bacteria; enteric viruses; and viable helminth

Table 3-7. Pathogen Requirements for All Class A Alternatives

The following requirements must be met for all six Class A

pathogen alternatives. Either:

• the density of fecal coliform in the sewage sludge must be less

than 1,000 most probable number (MPN) per gram total solids

(dry-weight basis),

or

• the density of Salmonella sp. bacteria in the sewage sludge must

be less than 3 MPN per 4 grams of total solids (dry-weight basis).

This requirement must be met at one of the following times:

• when the sewage sludge is used or disposed;

• when the sewage sludge is prepared for sale or give-away in a

bag or other container for land application; or

• when the sewage sludge or derived material is prepared to meet

the Part 503 requirements in 503.10(b), (c), (e), or (f)

Pathogen reduction must take place before or at the same time as

vector attraction reduction, except when the pH adjustment or

percent solids vector attraction reduction options are met, or if

vector attraction reduction is accomplished through injection or

incorporation.

Table 3-8. The Four Time-Temperature Regimes for Pathogen

Reduction Under Class A, Alternative 1

Regime Applies to: Requirement

Time-Temperature

Relationshipa

A Sewage sludge

with 7% solids or

higher (except

those covered by

Regime B)

Temperature of

sewage sludge

must be 50oC

or higher for

not less than

20 minutes

D = 131,700,000

100.1400T

(Equation 3 of

Section 503.32)

B Sewage sludge

with 7% solids or

higher in the

form of small

particles heated

by contact with

either warmed

gases or an

immiscible liquid

Temperature of

sewage sludge

must be 50oC

or higher for

not less than

15 seconds

D = 131,700,000

100.1400T

C Sewage sludge

with less than

7% solids 

Heated for

more than 15

seconds but

less than 30

minutes

D = 131,700,000

100.1400T

D Sewage sludge

with less than

7% solids

Temperature of

sludge is 50oC

or higher with

at least 30

minutes contact

time

D = 

50,070,000

10 0.1400T

(Equation 4 of

Section 503.32)

a

 D = time in days; T = temperature in degrees Celsius.

16
ova to demonstrate adequate reduction of pathogens,

as specified in the Part 503 rule.

If no enteric viruses or viable helminth ova are present

before treatment (i.e., in the feed sewage sludge), the

sewage sludge is Class A with respect to pathogens until

the next monitoring episode. Monitoring is continued

until enteric viruses or viable helminth ova are detected

in the feed sewage sludge, at which point the treated

sewage sludge is analyzed to see if these organisms

survived treatment. If enteric virus and viable helminth

ova densities are below detection limits, the sewage

sludge meets Class A requirements and will continue to

do so as long as the treatment process is operated

under the same conditions that successfully reduced the

enteric virus and viable helminth ova densities. Monitoring

for fecal coliform and Salmonella sp. bacteria, however,

must continue to be performed as indicated in Table 3-7.

Alternative 4: Sewage Sludge Treated in Unknown

Processes

This alternative is used primarily for stored sewage

sludge for which the history is unknown. It also can be

used when the process in which sewage sludge is

treated does not meet any of the descriptions of a

Process to Further Reduce Pathogens (PFRP). In this

alternative, a representative sample of the sewage

sludge must meet the Part 503 requirements for Salmonella sp. or fecal coliform bacteria (as described in Table

3-7); enteric viruses; and viable helminth ova at the time

the sewage sludge is used or disposed, prepared for

sale or give-away in a bag or other container for application to land, or prepared to meet “exceptional quality”

(EQ) land application requirements (as discussed later

in this chapter). The number of samples that have to be

collected and analyzed for pathogen densities is based

on the amount of sewage sludge that is land applied

annually (see the requirements for frequency of monitoring in the land application subpart of Part 503).

Alternative 5: Use of a PFRP

This alternative provides continuity with the 40 CFR Part

257 regulation (the predecessor to Part 503). For Alternative 5, sewage sludge qualifies as Class A if it has

been treated in one of the processes to further reduce

pathogens (PFRPs) (Table 3-9) and meets the regrowth

requirement in Table 3-7. The treatment processes must

be operated according to the PFRP process descriptions summarized in Table 3-9 at all times. The list of

processes in Table 3-9 (which appears as Appendix B in

the Part 503 regulation) is similar to the PFRP approaches listed in Part 257, with two major differences:

• All requirements concerning vector attraction have

been removed.

• All “add-on” processes listed in Part 257 are now

PFRPs because Part 503 contains separate requirements for vector attraction reduction.

Under this alternative, treatment processes classified as

PFRPs under Part 257 can continue to be operated;

however, microbiological monitoring (i.e., for fecal coliform or Salmonella sp. bacteria) must now be performed

to ensure that pathogen density levels are below detection limits and that regrowth of Salmonella sp. bacteria

does not occur between treatment and use or disposal

of the sewage sludge.

Alternative 6: Use of a Process Equivalent to a

PFRP

Under this alternative, sewage sludge is considered to

be Class A sewage sludge if it is treated by any process

equivalent to a PFRP and meets the regrowth requirement in Table 3-7. To be equivalent, a treatment process

Table 3-9. Processes To Further Reduce Pathogens (PFRPs)

Listed in the Part 503 Rule

1. Composting

Using either the within-vessel composting method or the static

aerated pile composting method, the temperature of the sewage

sludge is maintained at 55°C (131°F) or higher for 3 days.

Using the windrow composting method, the temperature of the

sewage sludge is maintained at 55°C (131°F) or higher for 15

days or longer. During the period when the compost is maintained

at 55°C (131°F) or higher, there shall be a minimum of five

turnings of the windrow.

2. Heat Drying

Sewage sludge is dried by direct or indirect contact with hot gases

to reduce the moisture content of the sewage sludge to 10% or

lower. Either the temperature of the sewage sludge particles

exceeds 80°C (176°F) or the wet bulk temperature of the gas in

contact with the sewage sludge as the sewage sludge leaves the

dryer exceeds 80°C (176°F).

3. Heat Treatment

Liquid sewage sludge is heated to a temperature of 180°C (356°F)

or higher for 30 minutes.

4. Thermophilic Aerobic Digestion

Liquid sewage sludge is agitated with air or oxygen to maintain

aerobic conditions and the mean cell residence time (i.e., the

solids retention time) of the sewage sludge is 10 days at 55°C

(131°F) to 60°C (140°F).

5. Beta Ray Irradiation

Sewage sludge is irradiated with beta rays from an electron

accelerator at dosages of at least 1.0 megarad at room

temperature (ca. 20°C [68°F]).

6. Gamma Ray Irradiation

Sewage sludge is irradiated with gamma rays from certain

isotopes, such as Cobalt 60 and Cesium 137, at dosages of at

least 1.0 megarad at room temperature (ca. 20°C [68°F]).

7. Pasteurization

The temperature of the sewage sludge is maintained at 70°C

(158°F) or higher for 30 minutes or longer.

17
must be able to consistently reduce pathogens to levels

comparable to the reduction achieved by a listed PFRP.

Processes must be operated at all times at the parameters described in the process description. The Part 503

rule gives the permitting authority responsibility for determining equivalency. To assist in making such determinations, the EPA’s Pathogen Equivalency Committee

(PEC) serves as a resource, providing recommendations on the equivalency of processes; the PEC also

provides guidance to the regulated community. Equivalency determinations can be made on a site-specific or

national basis. Processes recommended in Part 257 as

equivalent (Table 3-10) should yield sewage sludge that

meets Class A pathogen reduction requirements, as

long as microbiological requirements are also met.

3.4.1.2 Class B Pathogen Requirements

Bulk sewage sludge that is applied to agricultural land,

forests, public contact sites, or reclamation sites must

meet the Class B pathogen requirements if it does not

meet Class A pathogen requirements. Part 503 Subpart

D establishes three alternatives for demonstrating that

sewage sludge meets Class B pathogen requirements

(Table 3-6). The rule’s implicit objective for all three

approaches is to ensure that pathogenic bacteria and

enteric viruses are reduced in density, as demonstrated

by a fecal coliform density in the treated sewage sludge

of 2 million Most Probable Number (MPN) or colonyforming units (CFU) per gram total solids sewage sludge

(dry-weight basis). Viable helminth ova are not necessarily reduced in Class B sewage sludge.

Unlike Class A sewage sludge, which is essentially

pathogen-free, Class B sewage sludge contains some

pathogens. Therefore, site restrictions (Table 3-11) apply for a certain period when Class B sewage sludge is

land applied to allow environmental factors to further

reduce pathogens to below detectable levels. Additionally, Class B sewage sludge must meet a vector attraction requirement (see Section 3.4.2). The three

alternatives for meeting Part 503 Class B pathogen

reduction requirements are summarized below; more

detailed information on Class B pathogen requirements

can be found in another EPA document (U.S. EPA, 1992b).

Alternative 1: Monitoring of Fecal Coliform

This alternative requires that seven samples of treated

sewage sludge be collected at the time of use or disposal, and that the geometric mean fecal coliform density of these sample be less that 2 million CFU or MPN

per gram of sewage sludge solids (dry-weight basis).

Analysis of multiple samples is required during each

Table 3-11. Restrictions for the Harvesting of Crops and Turf,

Grazing of Animals, and Public Access on Sites

Where Class B Sewage Sludge is Land Applied

Restrictions for the harvesting of crops and turf:

1. Food crops with harvested parts that touch the sewage

sludge/soil mixture and are totally above ground shall not be

harvested for 14 months after application of sewage sludge.

2. Food crops with harvested parts below the land surface

where sewage sludge remains on the land surface for 4

months or longer prior to incorporation into the soil shall not

be harvested for 20 months after sewage sludge application.

3. Food crops with harvested parts below the land surface

where sewage sludge remains on the land surface for less

than 4 months prior to incorporation shall not be harvested for

38 months after sewage sludge application.

4. Food crops, feed crops, and fiber crops, whose edible parts

do not touch the surface of the soil, shall not be harvested for

30 days after sewage sludge application.

5. Turf grown on land where sewage sludge is applied shall

not be harvested for 1 year after application of the sewage

sludge when the harvested turf is placed on either land with a

high potential for public exposure or a lawn, unless otherwise

specified by the permitting authority.

Restriction for the grazing of animals:

1. Animals shall not be grazed on land for 30 days after

application of sewage sludge to the land.

Restrictions for public contact:

1. Access to land with a high potential for public exposure,

such as a park or ballfield, is restricted for 1 year after

sewage sludge application. Examples of restricted access

include posting with no trespassing signs, or fencing.

2. Access to land with a low potential for public exposure

(e.g., private farmland) is restricted for 30 days after sewage

sludge application. An example of restricted access is

remoteness.

Table 3-10. A Partial List of Processes Recommended as

Equivalent to PFRP Under Part 2571

Operator Process Description

Scarborough

Sanitary

District

Scarborough,

Maine

Static pile aerated “composting” operation that

uses fly ash from a paper company as a

bulking agent. The process creates pile

temperatures of 60°C to 70°C (140°F to

158°F) within 24 hours and maintains these

temperatures for up to 14 days. The material

is stockpiled after 7 to 14 days of “composting”

and then marketed.

Mount Holly

Sewage

Authority

Mount Holly,

New Jersey

Zimpro 50-gpm low-pressure wet air oxidation

process. The process involves heating raw

primary sewage sludge to 177°C to 204°C

(350°F to 400°F) in a reaction vessel under

pressures of 250 to 400 psig for 15 to 30

minutes. Small volumes of air are introduced

into the process to oxidize the organic solids.

Miami-Dade

Water and

Sewer

Authority

Miami, Florida

Anaerobic digestion followed by solar drying.

Sewage sludge is processed by anaerobic

digestion in two well-mixed digesters operating

in series in a temperature range of 35°C to

37°C (95°F to 99°F). Total residence time is 30

days. The sewage sludge is then centrifuged

to produce a cake of between 15% to 25%

solids. The sewage sludge cake is dried for 30

days on a paved bed at a depth of no more

than 46 cm (18 inches). Within 8 days of the

start of drying, the sewage sludge is turned

over at least once every other day until the

sewage sludge reaches a solids content of

greater than 70%.

1

These processes were all recommended for site-specific equivalency.

18
monitoring period because the methods used to determine fecal coliform density (i.e., membrane filter methods and the MPN dilution method) have poor precision

and because sewage sludge quality tends to vary. Use

of at least seven samples is expected to reduce the

standard error to a reasonable value.

Alternative 2: Use of a PSRP

Under this alternative, which provides continuity with

Part 257, sewage sludge is considered to be Class B if

it is treated in one of the processes to significantly

reduce pathogens (PSRPs) (Table 3-12). The list of

processes (which appears as Appendix B in the Part 503

regulation) is similar to the PSRP approaches listed in Part

257, except that all conditions related to reduction of vector

attraction have been removed. Unlike the comparable

Class A requirement, this alternative does not require microbiological monitoring because public access to the site

is restricted, allowing time for environmental conditions to

reduce pathogens to below detectable levels.

Alternative 3: Use of a Process Equivalent to a PSRP

Alternative 3 states that sewage sludge treated by any

process determined to be equivalent to a PSRP by the

permitting authority is considered to be a Class B sewage sludge. To assist the permitting authority in making

determinations, the EPA’s Pathogen Equivalency Committee (PEC) serves as a resource, providing recommendations on the equivalency of processes; the PEC

also provides guidance to the regulated community.

Equivalency determinations can be made on a site-specific or national basis. Processes recommended in Part

257 as equivalent (a partial list is provided in Table 3-13)

should yield sewage sludge that meets Class B pathogen requirements.

Table 3-12. Processes to Significantly Reduce Pathogens

(PSRPs) Listed in Part 503

1. Aerobic Digestion

Sewage sludge is agitated with air or oxygen to maintain aerobic

conditions for a specific mean cell residence time (i.e., solids

retention time) at a specific temperature. Values for the mean cell

residence time and temperature shall be between 40 days at 20°C

(68°F) and 60 days at 15°C (59°F).

2. Air Drying

Sewage sludge is dried on sand beds or on paved or unpaved

basins. The sewage sludge dries for a minimum of 3 months.

During 2 of the 3 months, the ambient average daily temperature

is above 0°C (32°F).

3. Anaerobic Digestion

Sewage sludge is treated in the absence of air for a specific 

mean cell residence time (i.e., solids retention time) at a specific

temperature. Values for the mean cell residence time and

temperature shall be between 15 days at 35°C to 55°C (131°F) 

and 60 days at 20°C (68°F).

4. Composting

Using either the within-vessel, static aerated pile, or windrow

composting methods, the temperature of the sewage sludge is

raised to 40°C (104°F) or higher and remains at 40°C (104°F) or

higher for 5 days. For 4 hours during the 5-day period, the

temperature in the compost pile exceeds 55°C (131°F).

5. Lime Stabilization

Sufficient lime is added to the sewage sludge to raise the pH of

the sewage sludge to 12 after 2 hours of contact.

Table 3-13. Selected Processes Recommended as Equivalent

to PSRP Under Part 2571

Operator Process Description

Town of Telluride,

Colorado

Combination oxidation ditch, aerated storage,

and drying process. Sewage sludge is treated

in an oxidation ditch for at least 26 days and

then stored in an aerated holding tank for up

to a week. Following dewatering to 18%

solids, the sewage sludge is dried on a paved

surface to a depth of 2 feet (0.6 m). The

sewage sludge is turned over during drying.

After drying to 30% solids, the sludge is

stockpiled prior to land application. Together,

the drying and stockpiling steps take

approximately 1 year. To ensure that PSRP

requirements are met, the stockpiling period

must include one full summer season.

Comprehensive

Materials

Management, Inc.

Houston, Texas

Use of cement kiln dust (instead of lime) to

treat sewage sludge by raising sewage sludge

pH to at least 12 after 2 hours of contact.

Dewatered sewage sludge is mixed with

cement kiln dust in an enclosed system.

N-Viro Energy

Systems, Ltd.

Toledo, Ohio

Use of cement kiln dust and lime kiln dust

(instead of lime) to treat sewage sludge by

raising the pH. Sufficient lime or kiln dust is

added to sewage sludge to produce a pH of

12 for at least 12 hours of contact.

Public Works

Department

Everett,

Washington

Anaerobic digestion of lagooned sewage

sludge. Suspended solids had accumulated in

a 30-acre (12-hectare) aerated lagoon that

had been used to aerate wastewater. The

lengthy detention time in the lagoon (up to 15

years) resulted in a level of treatment

exceeding that provided by conventional

anaerobic digestion. The percentage of fresh

or relatively unstabilized sewage sludge was

very small compared to the rest of the

accumulation (probably much less than 1% of

the whole).

Haikey Creek

Wastewater

Treatment Plant

Tulsa, Oklahoma

Oxidation ditch treatment plus storage.

Sewage sludge is processed in aeration

basins followed by storage in aerated sludge

holding tanks. The total sewage sludge

aeration time is greater than the aerobic

digestion operating conditions specified in the

Part 503 regulation of 40 days at 20°C (68°F)

to 60 days at 15°C (59°F). The oxidation ditch

sludge is then stored in batches for at least

45 days in an unaerated condition or 30 days

under aerated conditions.

Ned K. Burleson &

Associates, Inc.

Fort Worth, Texas

Aerobic digestion for 20 days at 30°C (86°F)

or 15 days at 35°C (95°F).

1

 All processes were recommended for site-specific equivalency, except the N-Viro System, which was recommended for national

equivalency.

19
3.4.2 Vector Attraction Reduction

Requirements

Subpart D in Part 503 establishes 10 options for demonstrating that sewage sludge that is land applied meets

requirements for vector attraction reduction (Table 3-14).

The options can be divided into two general approaches

for controlling the spread of disease via vectors (such

as insects, rodents, and birds):

• Reducing the attractiveness of the sewage sludge to

vectors (Options 1 to 8).

• Preventing vectors from coming into contact with the

sewage sludge (Options 9 and 10).

Compliance with the vector attraction reduction requirements using one of the options described below must be

demonstrated separately from compliance with requirements for reducing pathogens in sewage sludge. Thus,

demonstration of adequate vector attraction reduction does

not demonstrate achievement of adequate pathogen

reduction. Part 503 vector attraction reduction requirements are summarized below; for a detailed discussion

of vector attraction requirements, see U.S. EPA (1992b).

3.4.2.1 Option 1: Reduction in Volatile Solids

Content

Under this option, vector attraction is reduced if the

mass of volatile solids in the sewage sludge is reduced

by at least 38 percent during the treatment of the sewage sludge. This percentage is the amount of volatile

solids reduction that can be attained by anaerobic or

aerobic digestion plus any additional volatile solids reduction that occurs before the sewage sludge leaves the

treatment works, such as through processing in drying

beds or lagoons, or when sewage sludge is composted.

Table 3-14. Summary of Vector Attraction Reduction Requirements for Land Application of Sewage Sludge Under Part 503 

(U.S. EPA 1992b)

Requirement What Is Required? Most Appropriate For:

Option 1

503.33(b)(1)

At least 38% reduction in volatile solids during sewage

sludge treatment

Sewage sludge processed by:

• Anaerobic biological treatment

• Aerobic biological treatment

• Chemical oxidation

Option 2

503.33(b)(2)

Less than 17% additional volatile solids loss during

bench-scale anaerobic batch digestion of the sewage

sludge for 40 additional days at 30°C to 37°C (86°F to

99°F)

Only for anaerobically digested sewage sludge

Option 3

503.33(b)(3)

Less than 15% additional volatile solids reduction during

bench-scale aerobic batch digestion for 30 additional days

at 20°C (68°F) 

Only for aerobically digested sewage sludge with 2% or less

solids—e.g., sewage sludge treated in extended aeration

plants

Option 4

503.33(b)(4)

SOUR at 20°C (68°F) is ≤1.5 mg oxygen/hr/g total

sewage sludge solids

Sewage sludge from aerobic processes (should not be used

for composted sludges). Also for sewage sludge that has

been deprived of oxygen for longer than 1–2 hours.

Option 5

503.33(b)(5)

Aerobic treatment of the sewage sludge for at least 14

days at over 40°C (104°F) with an average temperature

of over 45°C (113°F) 

Composted sewage sludge (Options 3 and 4 are likely to be

easier to meet for sewage sludge from other aerobic

processes)

Option 6

503.33(b)(6)

Addition of sufficient alkali to raise the pH to at least 12 at

25°C (77°F) and maintain a pH ≥12 for 2 hours and a pH

≥11.5 for 22 more hours

Alkali-treated sewage sludge (alkalies include lime, fly ash,

kiln dust, and wood ash)

Option 7

503.33(b)(7)

Percent solids ≥75% prior to mixing with other materials Sewage sludges treated by an aerobic or anaerobic process

(i.e., sewage sludges that do not contain unstabilized solids

generated in primary wastewater treatment)

Option 8

503.33(b)(8)

Percent solids ≥90% prior to mixing with other materials Sewage sludges that contain unstabilized solids generated

in primary wastewater treatment (e.g., any heat-dried

sewage sludges)

Option 9

503.33(b)(9)

Sewage sludge is injected into soil so that no significant

amount of sewage sludge is present on the land surface

1 hour after injection, except Class A sewage sludge

which must be injected within 8 hours after the pathogen

reduction process.

Liquid sewage sludge applied to the land. Domestic septage

applied to agricultural land, a forest, or a reclamation site

Option 10

503.33(b)(10)

Sewage sludge is incorporated into the soil within 6 hours

after application to land. Class A sewage sludge must be

applied to the land surface within 8 hours after the

pathogen reduction process, and must be incorporated

within 6 hours after application.

Sewage sludge applied to the land. Domestic septage

applied to agricultural land, forest, or a reclamation site.

20
3.4.2.2 Option 2: Additional Digestion of

Anaerobically Digested Sewage Sludge

Under this option, an anaerobically digested sewage

sludge is considered to have achieved satisfactory vector attraction reduction if it loses less than 17 percent

additional volatile solids when it is anaerobically batchdigested in the laboratory in a bench-scale unit at 30° to

37°C (86° to 99°F) for an additional 40 days.

Frequently, sewage sludge is recycled through the biological wastewater treatment section of a treatment

works or resides for long periods of time in the wastewater collection system. During this time it undergoes

substantial biological degradation. If it is subsequently

treated by anaerobic digestion for a period of time, it is

adequately reduced in vector attraction; however, because sewage sludge enters the digester already partially stabilized, the volatile solids reduction after

treatment is frequently less than 38%. The additional

digestion test is used to demonstrate that the sewage

sludge is indeed satisfactorily reduced in vector attraction.

3.4.2.3 Option 3: Additional Digestion of

Aerobically Digested Sewage Sludge

Under this option, an aerobically digested sewage

sludge with 2 percent or less solids is considered to

have achieved satisfactory vector attraction reduction if

it loses less than 15 percent additional volatile solids

when it is aerobically batch-digested in the laboratory in

a bench-scale unit at 20°C (68°F) or higher for an additional 30 days. This test can be run on sewage sludge

with up to 2 percent solids and does not require a

temperature correction for sewage sludge not initially

digested at 20°C. Sewage sludge with greater than 2

percent solids can be diluted to 2 percent solids with

effluent, and the test can then be run on the diluted

sludge.

This option is appropriate for aerobically digested sewage sludge, including sewage sludge from extended

aeration and oxidation ditch plants where the nominal

residence time of sewage sludge leaving the wastewater treatment processes generally exceeds 20 days. In

these cases, the sewage sludge may already have been

substantially reduced in biological degradability prior to

aerobic digestion.

3.4.2.4 Option 4: Specific Oxygen Uptake Rate

(SOUR) for Aerobically Digested Sewage

Sludge Treated in an Aerobic Process

For sewage sludge treated in an aerobic process (usually aerobic digestion), reduction in vector attraction can

also be demonstrated if the SOUR of the sewage sludge

to be land applied is equal to or less than 1.5 mg of

oxygen per hour per gram of total sewage sludge solids

(dry-weight basis) at 20°C (68°F). The basis of this test

is that if the sewage sludge consumes very little oxygen,

its value as a food source for vectors is very low and

thus vectors are unlikely to be attracted to the sewage

sludge.

Frequently, aerobically digested sewage sludge is circulated through the aerobic biological wastewater treatment process for as long as 30 days. In these cases,

the sewage sludge entering the aerobic digester is already partially digested, which makes it difficult to demonstrate the 38 percent reduction required by Option 1;

Option 4 provides an alternative to the percent solids

method for demonstrating vector attraction reduction.

The oxygen uptake rate depends on the conditions of

the test and, to some degree, on the nature of the

original sewage sludge before aerobic treatment. It

should be noted that the SOUR method may be unreliable at solids content above 2 percent.

3.4.2.5 Option 5: Aerobic Processes at Greater

Than 40°C

Under this option, the sewage sludge must be treated

for 14 days or longer, during which time the temperature

must be over 40°C (104°) and the average temperature

higher than 45°C (113°F). This option applies primarily

to composted sewage sludge, which generally contains

substantial amounts of partially decomposed organic

bulking agents.

This option can be applied to sewage sludge from other

aerobic processes, such as aerobic digestion, but other

approaches for demonstrating compliance (e.g., those

described in Options 3 and 4) are likely to be easier to

meet for these types of sewage sludge.

3.4.2.6 Option 6: Addition of Alkali

Under this option, sewage sludge is considered to be

adequately reduced in vector attraction if sufficient alkali

is added to:

• Raise the pH to at least 12.

• Maintain a pH of at least 12 without addition of more

alkali for 2 hours.

• Maintain a pH of at least 11.5 without addition of more

alkali for an additional 22 hours.

The conditions required under this option are intended

to ensure that the sewage sludge can be stored for at

least several days at the treatment works, transported,

and then land applied without the pH falling to the point

where putrefaction occurs and vectors are attracted.

3.4.2.7 Option 7: Moisture Reduction of Sewage

Sludge Containing No Unstabilized Solids

Under this option, sewage sludge vector attraction is

considered to be reduced if the sewage sludge does not

21
contain unstabilized solids generated during primary

wastewater treatment and if the solids content of the

sewage sludge is greater than or equal to 75 percent

before the sewage sludge is mixed with other materials.

Thus, the reduction must be achieved by removing

water, not by adding inert materials.

It is important that the sewage sludge meeting Option 7

not contain unstabilized solids because the partially degraded food scraps likely to be present in such sewage

sludge would attract birds, some mammals, and possibly insects, even if the solids content of the sewage

exceeded 75 percent. Additionally, steps should be

taken to prevent exposure of stored sewage sludge to

high humidity, which could cause its outer surface to

equilibrate to a lower solids content and attract vectors.

3.4.2.8 Option 8: Moisture Reduction of Sewage

Sludge Containing Unstabilized Solids

Vector attraction of any sewage sludge is considered to

be adequately reduced if the solids content of the sludge

is increased to 90 percent or greater. This extreme

desiccation deters vectors in all but the most unusual

situations. The solids increase must be achieved by

removal of water and not by dilution with inert solids.

Drying to this extent severely limits biological activity

and strips off or decomposes the volatile compounds

that attract vectors.

3.4.2.9 Option 9: Injection of Sewage Sludge

Vector attraction reduction can be demonstrated by injecting the sewage sludge below the ground. Under this

option, no significant amount of the sewage sludge can

be present on the land surface within 1 hour after injection. If the sludge is Class A with respect to pathogens,

it must be injected within 8 hours after discharge from

the pathogen-reduction process; special restrictions apply to Class A sewage sludge because it is a medium

for regrowth, and after 8 hours pathogenic bacteria may

rapidly increase.

Injection of sewage sludge beneath the soil places a barrier of earth between the sewage sludge and vectors. The

soil quickly removes water from the sewage sludge, which

reduces the mobility and odor of the sewage sludge.

3.4.2.10 Option 10: Incorporation of Sewage

Sludge into the Soil

Under this option, sewage sludge applied to the land

surface must be incorporated into the soil within 6 hours.

If the sewage sludge is Class A with respect to pathogens, the time between processing and application must

not exceed 8 hours.

When applied at agronomic rates, the loading of sewage

sludge solids typically is approximately 1/200th or less

of the mass of soil in the plow layer. If mixing is reasonably good, the dilution of sewage sludge in the soil

surface is equivalent to that achieved with soil injection.

Initial vector attraction will diminish and be virtually eliminated when the sewage sludge is mixed with the soil.

3.5 Frequency of Monitoring

The Part 503 rule requires that pollutant concentrations

(for metals), pathogen densities, and vector attraction

reduction be monitored and analyzed when sewage

sludge is land applied. Monitoring is intended to ensure

that the land-applied sewage sludge meets applicable

criteria after its quality has been initially demonstrated.

Part 503 specifies how often sewage sludge must be

monitored and lists the analytical methods to be used

for analyzing different types of samples. The frequency

of monitoring requirements range from 1 to 12 times per

year, depending on the amount of sewage sludge (in

metric tons, dry-weight basis) applied to a site. Requirements for monitoring must be met regardless of which

approaches are used for meeting pollutant limits and

pathogen and vector attraction reduction requirements.

Frequency of monitoring requirements are summarized

in Table 3-15. For frequency of monitoring requirements

for stored sewage sludge, contact the permitting authority.

3.6 Recordkeeping and Reporting

The person who prepares sewage sludge for land application must provide information necessary to demonstrate compliance with the Part 503 rule to the land

applier, and the person who applies the sewage sludge

to the land is responsible for obtaining from the preparer

information necessary to demonstrate compliance with

the rule. For a discussion of specific Part 503 recordkeeping and reporting requirements, see Chapter 15.

3.7 Sewage Sludge Quality and the Part

503 Requirements

The Part 503 requirements that must be complied with

depend on the quality of the sewage sludge, in terms of

pollutants, pathogen levels, and vector attraction reduction control. These quality differences are discussed

below and are summarized in Table 3-16.

3.7.1 Exceptional Quality (EQ) Sewage Sludge

Sewage sludge that meets the Part 503 ceiling concentration limits, pollutant concentration limits, one of the

Class A pathogen reduction alternatives, and one of the

vector attraction reduction options described above can

be considered “exceptional quality” (EQ) sewage sludge.3

Sewage sludge meeting these EQ requirements are not

3

 The sewage sludge quality designation “exceptional quality” is

based on interpretations of the Part 503 rule, which does not explicitly use this term.

22
subject to Part 503’s land application general requirements and management practices. EQ sewage sludge

can be applied as freely as any other fertilizer or soil

amendment to any type of land (unless EPA or the

director of an EPA-approved state sludge program determines that in a particular case, when bulk sewage

sludge is land applied, the Part 503 general requirements or management practices are needed to protect

public health and the environment). Although the Part

503 rule does not require EQ sewage sludge to be

applied at the agronomic rate for nitrogen (which is a

requirement for sewage sludge not meeting EQ requirements), for good management EQ sewage sludge, like

any type of fertilizer, also should be applied at the agronomic rate, which supplies the nitrogen needs of the

crop or vegetation grown on the site and protects ground

water.

To achieve EQ sewage sludge quality, the user or

preparer of sewage sludge must:

• Not exceed the Part 503 ceiling concentration limits

and pollutant concentration limits for regulated metals

(Table 3-4).

• Meet one of the six Part 503 Class A pathogen reduction alternatives (Table 3-6) and required bacterial

monitoring (Table 3-7).

• Meet one of the first eight Part 503 vector attraction

reduction options (Table 3-14).

• Comply with the Part 503 frequency of monitoring

(Table 3-15) and recordkeeping/reporting requirements (see Chapter 15).

Table 3-15. Frequency of Monitoring for Pollutants, Pathogen Densities, and Vector Attraction Reduction

Amount of Sewage Sludge (U.S. tons)

Amounts of Sewage Sludgea

(metric tons per 365-day period) Ave. per day per 365 days Frequency

Greater than zero but less than 290 >0 to <0.85 >0 to <320 Once per year

Equal to or greater than 290 but

less than 1,500

0.85 to <4.5 320 to <1,650 Once per quarter

(4 times per year)

Equal to or greater than 1,500 but

less than 15,000

 4.5 to <45 1,650 to <16,500 Once per 60 days

(6 times per year)

Equal to or greater than 1,5000 ≥45 ≥16,500 Once per month

(12 times per year)

a

 Either the amount of bulk sewage sludge applied to the land or the amount of sewage sludge received by a person who prepares sewage

sludge for sale or give-away in a bag or other container for application to the land (dry-weight basis).

Table 3-16. Summary of Part 503 Requirements for Different Types of Sewage Sludge

Type of

Sewage

Sludgea

Ceiling

Concentration

Limit

Other

Pollutant

Limits

Pathogen 

Class

Vector

Attraction

Reduction

Siting

Restrictions

General

Requirements,

Management

Practices

Track

Added

Pollutants

“Exceptional

Quality” 

(Bag or Bulk)

Yes Pollutant

Concentration

Limits 

A 1 of

Options

1-8b

No Nob No

Pollutant

Concentration

(Bulk Only)

Yes Pollutant

Concentration

Limits

B 1 of

Options

1-10

Yes Yes No

CPLR 

(Bulk Only)

Yes Cumulative

Pollutant

Loading

Rates

(CPLRs)

A or B 1 of

Options

1-10

No if

Pathogen

Class A

Yes if

Pathogen

Class B

Yes Yes

APLR 

(Bag Only)

Yes Annual

Pollutant

Loading

Rates

(APLRs)

A 1 of

Options 

1-8

No Yesc No

a

 All sewage sludge must also meet Part 503 frequency of monitoring requirements and recordkeeping and reporting requirements.

b If sewage sludge instead follows vector attraction reduction options 9 or 10 (incorporation or injection), the sewage sludge must also meet

Part 503 general requirements and management practices, and would not be considered “exceptional quality” sewage sludge. c

 Only two general requirements and a management practice requirement for labeling must be met.

23
The Part 503 general requirements and management

practices do not apply to EQ sewage sludge unless they

are deemed necessary for bulk sewage sludge, as discussed above.

3.7.2 Pollutant Concentration (PC) Sewage

Sludge

“Pollutant Concentration” (PC) sewage sludge meets

the same low pollutant limits as EQ sewage sludge, but

usually meets Class B rather than Class A pathogen

reduction requirements. Sewage sludge meeting Class

A pathogen reduction requirements and vector attraction

options 9 or 10 (which do not qualify as EQ vector

requirements) also is PC sewage sludge. If PC sewage

sludge is Class B pathogen status, it must be land

applied according to specific site restrictions discussed

in Table 3-11 to prevent exposure to the sewage sludge.

Sewage sludge that meets PC criteria can be applied to

all types of land, except lawns and home gardens, if

these site restrictions are observed. To achieve PC sewage sludge quality, the sewage sludge must:

• Not exceed the Part 503 ceiling concentration limits

and pollutant concentration limits for regulated metals

(Table 3-4).

• Meet one of three Part 503 Class B pathogen reduction alternatives (Table 3-6) and Class B site restrictions (Table 3-11).

• Meet one of 10 applicable Part 503 vector attraction

reduction options (Table 3-14).

• Comply with the Part 503 frequency of monitoring

(Table 3-15) and recordkeeping/reporting requirements (see Chapter 15).

• Comply with certain Part 503 general requirements

(Table 3-17) and management practices (Table 3-5).

3.7.3 Cumulative Pollutant Loading Rate

(CPLR) Sewage Sludge

“CPLR” sewage sludge must meet more Part 503 requirements than EQ or PC sewage sludge. These requirements, such as tracking of cumulative metal

loadings, ensures adequate protection of public health

and the environment. CPLR sewage sludge users or

preparers must:

• Not exceed the Part 503 ceiling concentration limits

and cumulative pollutant loading rate (CPLR) limits

for regulated metals (Table 3-4) when the sewage

sludge is land applied in bulk.

• Meet either Part 503 Class A or Class B pathogen

reduction requirements (Table 3-6) and related requirements (either Table 3-7 or Table 3-11).

• Meet one of 10 Part 503 vector attraction reduction

options (Table 3-14).

• Comply with Part 503 frequency of monitoring (Table

3-15) and recordkeeping/reporting requirements (see

Chapter 15).

• Comply with certain Part 503 general requirements

(Table 3-17) and management practices (Table 3-5).

3.7.4 Annual Pollutant Loading Rate (APLR)

Sewage Sludge

“APLR” sewage sludge, which pertains only to sewage

sludge sold or given away in a bag or other container for

application to land (“bagged” sewage sludge), must

meet Class A pathogen reduction requirements and one

of the vector attraction reduction treatment options.

These provisions are required because of the high potential for human contact at sites where bagged sewage

sludge is likely to be applied (i.e., public contact sites

such as parks). APLR sewage sludge users or preparers

must:

• Not exceed the Part 503 ceiling concentration limits

and annual pollutant loading rate (APLR) limits for

regulated metals (Table 3-4) when the sewage sludge

is placed in a bag or other container, as defined in

Part 503, for sale or given away for application to the

land.

• Meet Part 503 Class A pathogen reduction requirements (Table 3-6) and required bacterial monitoring

(Table 3-7).

• Meet one of the first eight Part 503 vector attraction

reduction options (Table 3-14).

• Meet the Part 503 management practice that requires

a label or information sheet that lists data specified

in Part 503 (Table 3-5).

• Meet the Part 503 frequency of monitoring (Table

3-15) and recordkeeping/reporting requirements (see

Chapter 15).

• Meet the Part 503 general requirements (Part

503.12(a) and (e)(i)).

The Part 503 labelling provision requires that the

preparer of APLR sewage sludge provide the applier

with allowable application rate information, either on a

label or in a handout (usually based on the nutrient

content of the sewage sludge). This information is based

on the preparer’s calculation of the annual whole sludge

application rate (AWSAR) (Table 3-18). The preparer/

manufacturer also provides the applier with information

on the nutrient value of the bagged sewage sludge. The

recommended application rate helps ensure that the

sewage sludge is applied at the appropriate agronomic

rate to minimize the amount of excess nitrogen that

passes below the root zone and into ground water.

24
Table 3-17. Part 503 Land Application General Requirements 

For EQ Sewage Sludge

None (unless set by EPA or state permitting authority on a

case-by-case basis for bulk sewage sludge to protect public health

and the environment).

For PC and CPLR Sewage Sludge

The preparera must notify and provide information necessary to

comply with the Part 503 land application requirements to the

person who applies bulk sewage sludge to the land. 

The preparer who provides sewage sludge to another person who

further prepares the sewage sludge for application to the land

must provide this person with notification and information

necessary to comply with the Part 503 land application

requirements.

The preparer must provide written notification of the total nitrogen

concentration (as N on a dry-weight basis) in bulk sewage sludge

to the applier of bulk sewage sludge to agricultural land, forests,

public contact sites, or reclamation sites.

The applier of sewage sludge must obtain information necessary

to comply with the Part 503 land application requirements, apply

sewage sludge to the land in accordance with the Part 503 land

application requirements, and provide notice and relevant

information to the owner or lease holder of the land on which

sewage sludge is applied.

Out-of-State Use

The preparer must provide written notification (prior to the initial

application of the bulk sewage sludge by the applier) to the

permitting authority in the state where sewage sludge is proposed

to be land applied when bulk sewage sludge is generated in one

state (the generating state) and transferred to another state (the

receiving state) for application to the land. The notification must

include: 

• the location (either street address or latitude and longitude) of

each land application site;

• the approximate time period the bulk sewage sludge will be

applied to the site;

• the name, address, telephone number, and National Pollutant

Discharge Elimination System (NPDES) permit number for both

the preparer and the applier of the bulk sewage sludge; and

• additional information or permits in both states, if required by the

permitting authority.

Additional Requirements for CPLR Sewage Sludge

The applier must notify the permitting authority in the state where

bulk sewage sludge is to be applied prior to the initial application

of the sewage sludge. This is a one-time notice requirement for

each land application site each time there is a new applier. The

notice must include: 

• the location (either street address or latitude and longitude) of the

land application site; and

• the name, address, telephone number, and NPDES permit

number (if appropriate) of the person who will apply the bulk

sewage sludge.

The applier must obtain records (if available) from the previous

applier or landowner that indicate the amount of each CPLR

pollutant in sewage sludge that have been applied to the site since

July 20, 1993. In addition:

• when CPLR sewage sludge was previously applied since July 20,

1993 to the site and cumulative amounts of regulated pollutants

are known, the applier must use this information to determine the

additional amount of each pollutant that can be applied to the site

in accordance with the CPLRs in Table 3-4;

• the applier must keep the previous records and also record the

additional amount of each pollutant he or she is applying to

the site; and

• when CPLR sewage sludge was previously applied to the site

and cumulative amounts of regulated pollutants are not known, no

additional sewage sludge meeting CPLRs can be applied to that

site. However, EQ or PC sewage sludge could be applied.

If sewage sludge meeting CPLRs has not been applied to the site

in excess of the limit since July 20, 1993, the CPLR limit for each

pollutant in Table 3-4 will determine the maximum amount of each

pollutant that can be applied if the applier keeps a record of the

amount of each pollutant in sewage sludge applied to any given

site.

The applier must not apply additional sewage sludge under the

cumulative pollutant loading concept to a site where any of the

CPLRs have been reached.

a

 The preparer is either the person who generates the sewage sludge or the person who derives a material from sewage sludge. This includes

the person who prepares sewage sludge for sale or give-away in a bag or other container for application to the land.

25
3.8 References

When an NTIS number is cited in a reference, that 

document is available from:

 National Technical Information Service

 5285 Port Royal Road

 Springfield, VA 22161

 703-487-4650

U.S. EPA. 1994. A plain English guide to the EPA Part 503 biosolids

rule. EPA/832/R-93/003. Washington, DC.

U.S. EPA. 1992a. Technical support document for land application of

sewage sludge, Vol. 1. EPA/822/R-93/018a (NTIS PB93110575).

Washington, DC.

U.S. EPA. 1992b. Environmental regulations and technology: Control

of pathogens and vector attraction in sewage sludge. EPA/625/R92/013. Washington, DC.

Table 3-18. Procedure to Determine the Annual Whole Sludge Application Rate for Sewage Sludge Sold or Given Away in a Bag

or Other Container for Application to Land

1. Analyze a sample of the sewage sludge to determine the concentration of each of the 10 regulated metals in the sewage sludge.

2. Using the pollutant concentrations from Step 1 and the APLRs from Table 3-4, calculate an AWSAR for each pollutant using the following

equation:

AWSAR = APLR

C ⋅ 0.001

where:

AWSAR = Annual whole sludge application rate (dry metric tons of sewage sludge/hectare/year)

APLR = Annual pollutant loading rate (in Table 3-4) (kg of pollutant/ha/yr)

C = Pollutant concentration (mg of pollutant/kg of sewage sludge, dry weight)

 0.001 = A conversion factor

3. The AWSAR for the sewage sludge is the lowest AWSAR calculated for each pollutant in Step 2. 

Example:

a. Sewage sludge to be applied to land is analyzed for each of the 10 metals regulated in Part 503. Analysis of the sewage sludge

indicates the pollutant concentration in the second column of the table below.

b. Using these test results and the APLR for each pollutant from Table 3-4, the AWSAR for all the pollutants are calculated as shown in the

fourth column of the table below.

c. The AWSAR for the sewage sludge is the lowest AWSAR calculated for all 10 metals. In our example, the lowest AWSAR is for copper

at 20 metric tons of sewage sludge/hectare/year. Therefore, the AWSAR to be used for this sewage sludge is 20 metric tons per

hectare/year. The 20 metric tons of sewage sludge/hectare is the same as 410 pounds of sewage sludge/1,000 square feet (20 metric tons

× 2,205 lb per metric ton/107,600 square feet per hectare). The AWSAR on the label or information sheet would have to be equal to or less

than 410 pounds per 1,000 square feet.

Metal

Sewage Sludge

Concentrations

(milligrams/kilogram)

APLRa

(kilograms/

hectare/year)

AWSAR =

APLR

Conc. in Sewage Sludge (0.001)

= metric tons ⁄ hectare ⁄ year

Arsenic 10 2.0 2/(10 × 0.001) = 200

Cadmium 10 1.9 1.9/(10 × 0.001) = 190

Chromium 1,000 150 150/(1,000 × 0.001) = 150

Copper 3,750 75 75/(3,750 × 0.001) = 20

Lead 150 15 15/(150 × 0.001) = 100

Mercury 2 0.85 0.85/(2 × 0.001) = 425

Molybdenum — — —

Nickel 100 21 21/(100 × 0.001) = 210

Selenium 15 5.0 5/(15 × 0.001) = 333

Zinc 2,000 140 140/(2,000 × 0.001) = 70 

a Annual pollutant loading rates from Table 3-4 of this guide and Table 4 of the Part 503 rule. The APLR for molybdenum does not have to be

met while EPA is reconsidering this value.

26
Chapter 4

Characteristics of Sewage Sludge

4.1 Introduction

Determining the suitability of sewage sludge for land application by characterizing its properties is a necessary first

step in planning and designing a land application system.

The composition of sewage sludge will have important

bearing on the following design decisions:

• Whether the sewage sludge can be cost-effectively

applied to land.

• Which land application practice (i.e., application to

agricultural, forest, reclamation or public contact

sites) is technically feasible.

• The quantity of sewage sludge to be applied per unit

area, both annually and cumulatively.

• The degree of regulatory control and system monitoring required.

Important properties of sewage sludge that need to be

characterized include:

• Quantity

• Total solids content

• Volatile solids content

• pH

• Organic matter

• Pathogens

• Nutrients

• Metals

• Organic chemicals

• Hazardous pollutants, if any

Sewage sludge composition depends principally on the

characteristics of the wastewater influent entering the

wastewater treatment works and the treatment processes used. Generally, the more industrialized a community is, the greater the possibility that heavy metals

may pose a potential problem for land application of

sewage sludge. Industrial pretreatment requirements

(40 CFR Part 403) and pollution prevention programs,

as well as advances in wastewater and sewage sludge

treatment processes, generally have reduced the levels

of pollutants in the final sewage sludge leaving a treatment works. Figure 4-1 shows the basic wastewater and

sewage sludge generation and treatment process.

This chapter describes the properties of sewage sludge

to be characterized, the different types of sewage sludge

(which exhibit different characteristics), and the effects

that wastewater and sewage sludge treatment processes and pretreatment have on sewage sludge

characteristics. The information provided is intended

primarily for illustrative purposes. While the data are

useful in preliminary planning, analysis of the actual

sewage sludge to be land-applied is necessary for design purposes. The chemical composition of sewage

sludge may vary greatly between wastewater treatment

works and also over time at a single plant. This variability in sewage sludge composition underscores the need

for a sound sampling program (e.g., analysis of a substantial number of sewage sludge samples over a period

of 2 to 6 months or longer) to provide a reliable estimate

of sewage sludge composition. Sampling is discussed

in Chapters 6 and 13.

4.2 Sewage Sludge Quantity

The amount of sewage sludge to be land applied will

affect site evaluation and design in several important

ways, including land area needs, size of transportation

equipment and storage facilities, and cost. Quantities of

sewage sludge available also will affect the selection of

land application practices (i.e., application at agricultural, forest, reclamation or public contact sites), as well

as application rates and operating schedules.

Sewage sludge quantity can be measured in two ways:

the volume of the wet sewage sludge, which includes

the water content and solids content, or the mass of the

dry sewage sludge solids. Sewage sludge volume is

expressed as gallons (liters) or cubic meters, while

sludge mass usually is expressed in terms of weight, in

units of dry metric tons (tonnes). Because the water

content of sewage sludge can be high and quite variable, the mass of dry sludge solids is often used to

compare sewage sludges with different proportions of

water (U.S. EPA, 1984).

27
SEWAGE SLUDGE

DOMESTIC SEPTAGE

Figure 4-1. Generation, treatment, use, and disposal of sewage sludge and domestic septage.

28
Key factors affecting sewage sludge volume and mass

are wastewater sources and wastewater and sludge

treatment processes. For example, industrial contributions to wastewater influent streams can significantly

increase the sewage sludge quantity generated from a

given amount of wastewater. Also, higher degrees

of wastewater treatment generally increase sewage

sludge volume. In addition, as shown in Table 4-1, some

sewage sludge treatment processes reduce sewage

sludge volume, some reduce sewage sludge mass, and

some increase sewage sludge mass while improving

other sewage sludge characteristics (U.S. EPA, 1984).

4.3 Total Solids Content

The total solids (TS) content of sewage sludge includes

the suspended and dissolved solids and is usually expressed as the percent of total solids present in a sewage sludge. TS can affect the potential land application

system design in several ways, including:

• Size of transportation and storage systems—The

higher the solids content, the lower the volume of

sewage sludge that will have to be transported and

stored because less water will need to be handled.

• Mode of transport—Different types of transportation

to the land application site (e.g., trucks, pipelines) will

be used depending on the solids content of the sewage sludge to be applied (see Chapter 14).

• Application method and equipment—The method of

sewage sludge application (e.g., surface spreading,

injection, spray irrigation) and the type of application

equipment needed will vary depending on the solids

content of the sewage sludge (see Chapter 14).

• Storage method—Different storage methods will be

used depending on solids content (e.g., tanks for

liquid sewage sludge versus stockpiles for dewatered

sewage sludge).

In general, it is less expensive to transport sewage

sludge with a high solids content (dewatered sewage

sludge) than to transport sewage sludge with a low

solids content (liquid sewage sludge). This cost savings

in transport should be weighed against the cost of dewatering the sewage sludge. Typically, liquid sewage

sludge has a solids content of 2 to 12 percent solids,

while dewatered sewage sludge has a solids content of

12 to 40 percent solids (including chemical additives).

Dried or composted sewage sludge typically has a solids content over 50 percent.

TS content depends on the type of sewage sludge

(primary, secondary, or tertiary, as discussed in Section

4.12), whether the sewage sludge has been treated prior

to land application, and how it was treated. Treatment

processes such as thickening, conditioning, dewatering,

composting, and drying can lower water content and

thus raise the percent solids. The efficiency of these

treatment processes, however, can vary substantially

from time to time, producing sewage sludge with substantially lower solids content than anticipated. Land

application sites, therefore, should be flexibly designed

to accommodate the range of variations in sewage

sludge solids content that may occur as a result of

variations in the efficiency of the wastewater and sewage sludge treatment processes. Without this flexibility,

operational problems could result at the site.

4.4 Volatile Solids Content

Sludge volatile solids (VS) are organic compounds that

are reduced when the sludge is heated to 550°C

(1,022°F) under oxidizing conditions. The VS content of

sludge provides an estimate of the organic content of

the material. VS content is most often expressed as the

percent of total solids that are volatile solids. VS is an

important determinant of potential odor problems at land

application sites. Reduction of VS is one option in the

Part 503 regulation for meeting vector attraction reduction requirements (see Chapter 3). Most unstabilized

sewage sludge contains 75 percent to 85 percent VS on

a dry weight basis. A number of treatment processes,

including anaerobic digestion, aerobic digestion, alkali

stabilization, and composting, can be used to reduce

sludge VS content and thus the potential for odor. Anaerobic digestion—the most common method of sludge

stabilization—generally biodegrades about 50 percent

of the volatile solids in a sewage sludge.

4.5 pH

The pH of sewage sludge can affect crop production at

land application sites by altering the pH of the soil and

influencing the uptake of metals by soil and plants.

Pathogen levels and vector control are the major reasons for pH adjustment of sewage sludge. Low pH

sludge (less than approximately pH 6.5) promotes

leaching of heavy metals, while high pH sludge (greater

than pH 11) kills many bacteria and, in conjunction with

soils of neutral or high pH, can inhibit movement of

heavy metals through soils. Some of the Part 503 pathogen reduction alternatives include raised pH levels (see

Chapter 3).

4.6 Organic Matter

The relatively high level of organic matter in sewage

sludge allows the sludge to be used as a soil conditioner

to improve the physical properties of soil (e.g., increased

water infiltration and water-holding capacity). The soil

conditioning properties of sewage sludge are especially

useful at reclamation sites such as mine spoils.

29
Table 4-1. Effects of Sewage Sludge Treatment Processes on Land Application Practices (U.S. EPA, 1984)

Treatment Process and Definition Effect on Sewage Sludge Effect on Land Application Practices

Thickening: Low-force separation of

water and solids by gravity, flotation, or

centrifugation. (Sewage sludge thickeners

may also be used as flow equalization

tanks to minimize the effect of sewage

sludge quantity fluctuations on subsequent

treatment processes.)

Increase solids concentration of sewage

sludge by removing water, thereby

lowering sewage sludge volume. May

provide a blending function in combining

and mixing primary and secondary

sewage sludges. 

Lowers sewage sludge transportation

costs for all practices (e.g, agricultural,

forests, reclamation sites, public contact

sites).

Digestion (Anaerobic and Aerobic):

Biological stabilization of sewage sludge

through conversion of some of the organic

matter to water, carbon dioxide, and

methane. (Digesters may also be used to

store sewage sludge to provide greater

flexibility for the treatment operation and

to homogenize sewage sludge solids to

facilitate subsequent handling procedures.)

Reduces the volatile and biodegradable

organic content and the mass of sewage

sludge by converting it to soluble material

and gas. May reduce volume by

concentrating solids. Reduces pathogen

levels and controls putrescibility and odor.

Reduces sewage sludge quantity. 

Alkali Stabilization: Stabilization of

sewage sludge through the addition of

alkali.

Raises sewage sludge pH. Temporarily

decreases biological activity. Reduces

pathogen levels and controls putrescibility.

Increases the dry solids mass of the

sewage sludge. Because pH effects are

temporary, decomposition, leachate

generation, and release of gas, odors,

and heavy metals may occur over time.

High pH of alkali-stabilized sewage sludge

tends to immobilize heavy metals in

sewage sludge as long as the pH levels

are maintained.

Conditioning: Alteration of sewage

sludge properties to facilitate the

separation of water from sewage sludge.

Conditioning can be performed in many

ways, e.g., adding inorganic chemicals

such as lime and ferric chloride; adding

organic chemicals such as polymers;

mixing digested sewage sludge with water

and resettling (elutriation); or briefly raising

sewage sludge temperature and pressure

(heat treatment). Thermal conditioning

also causes disinfection.

Improves sewage sludge dewatering

characteristics. Conditioning may increase

the mass of dry solids to be handled

without increasing the organic content of

the sewage sludge. Conditioning may also

improve sewage sludge compactability

and stabilization. Generally, polymertreated sewage sludges tend to be sticky,

slick, and less workable than other

sewage sludges. Some conditioned

sewage sludges are corrosive.

Polymer-treated sewage sludges may

require special operational considerations

at the land application site.

Dewatering: High-force separation of

water and solids. Dewatering methods

include vacuum filters, centrifuges, filter

presses, belt presses, lagoons, and sand

drying beds. 

Increases solids concentration of sewage

sludge by removing much of the entrained

water, thereby lowering sewage sludge

volume. Dewatering may increase sewage

sludge solids to 15% to 40% for organic

sewage sludges and 45% or more for

some inorganic sewage sludges. Some

nitrogen and other soluble materials are

removed with the water. Improves ease of

handling by converting liquid sewage

sludge to damp cake. Reduces fuel

requirements for heat drying.

Reduces land requirements and lowers

sewage sludge transportation costs for all

practices.

Composting: Aerobic process involving

the biological stabilization of sewage

sludge in a windrow, aerated static pile,

or vessel.

Lowers biological activity. Can destroy

most pathogens. Degrades sewage

sludge to a humus-like material. Increases

sewage sludge mass due to addition of

bulking agent.

Excellent soil conditioning properties.

Significant storage usually needed. May

contain lower nutrient levels than less

processed sewage sludge.

Heat Drying: Application of heat to kill

pathogens and eliminate most of the

water content. 

Disinfects sewage sludge. Destroys most

pathogens. Slightly lowers potential for

odors and biological activity.

Greatly reduces volume of sewage sludge.

30
4.7 Pathogens

Potential disease-causing microorganisms known as

pathogens, including bacteria, viruses, protozoa, and

eggs of parasitic worms, are often present in municipal

wastewater and raw sewage sludge. Pathogens also

are present in domestic septage. Pathogens can present a public health hazard if they are transferred to food

crops grown on land to which sewage sludge or domestic septage is applied, contained in runoff to surface

waters from land application sites, or transported away

from the site by vectors such as insects, rodents, and

birds. For this reason, Part 503 specifies pathogen reduction and vector attraction reduction requirements

that must be met by sewage sludge applied to land

application sites. Table 4-2 illustrates the different types

of pathogens typically found in sewage sludge and domestic septage.

Generally, sewage sludge intended for land application

is stabilized by chemical or biological processes (see

Section 4.13). Table 4-3 shows typical levels of some

pathogens in unstabilized and stabilized sewage sludge.

Stabilization greatly reduces the number of pathogens

in sewage sludge, including bacteria, parasites, protozoa, and viruses (Sagik et al., 1979), as well as odor

potential. Nevertheless, even stabilized sewage sludge

will usually contain some pathogens; thus the Part 503

regulation requires that specific processes to reduce

pathogen levels be undertaken prior to land application

and that site restrictions for certain types of sewage

sludge be followed. The Part 503 pathogen and vector

attraction reduction requirements serve to protect operating personnel, the general public, crops intended for

human consumption, ground water, and surface water

from potential contamination by unacceptable levels of

pathogens. Part 503 requirements also are designed to

ensure that regrowth of bacteria does not occur prior to

use or disposal. A summary of the Part 503 pathogen

and vector attraction reduction requirements is presented in Chapter 3. For more detailed discussions of

Table 4-2. Principal Pathogens of Concern in Municipal

Wastewater and Sewage Sludge

Organism Disease/Symptoms

Bacteria

Salmonella sp. Salmonellosis (food poisoning),

typhoid fever

Shigella sp. Bacillary dysentery

Vibrio cholerae Cholera

Campylobacter jejuni Gastroenteritis

Escherichia coli

(pathogenic strains)

Gastroenteritis

Enteric Viruses

Hepatitis A virus Infectious hepatitis

Norwalk and Norwalk-like

viruses

Epidemic gastroenteritis with severe

diarrhea

Rotaviruses Acute gastroenteritis with severe

diarrhea

Enteroviruses

Polioviruses

Coxsackieviruses

Echoviruses

Poliomyelitis

Meningitis, pneumonia, hepatitis, fever,

cold-like symptoms, diarrhea, etc.

Meningitis, paralysis, encephalitis, fever,

cold-like symptoms, diarrhea, etc.

Reovirus Respiratory infections, gastroenteritis

Astroviruses Epidemic gastroenteritis

Calciviruses Epidemic gastroenteritis

Protozoa

Cryptosporidium Gastroenteritis

Entamoeba histolytica Acute enteritis

Giardia lamblia Giardiasis (including diarrhea,

abdominal cramps, weight loss)

Balantidium coli Diarrhea and dysentery

Toxoplasma gondi Toxoplasmosis

Helminth Worms

Ascaris lumbricoides Digestive and nutritional

disturbances, abdominal pain,

vomiting, restlessness

Ascaris suum May produce symptoms such as

coughing, chest pain, and fever

Trichuris trichiura Abdominal pain, diarrhea, anemia,

weight loss

Toxocara canis Fever, abdominal discomfort, muscle

aches, neurological symptoms

Taenia saginata Nervousness, insomnia, anorexia,

abdominal pain, digestive

disturbances

Taenia solium Nervousness, insomnia, anorexia,

abdominal pain, digestive

disturbances

Necator americanus Hookworm disease

Hymenolepis nana Taeniasis

Table 4-3. Typical Pathogen Levels in Unstabilized and

Anaerobically Digested Liquid Sludges (U.S. EPA, 1979)

Pathogen

Typical

Concentration in

Unstabilized

Sludge

(No./100 milliliters)

Typical

Concentration in

Anaerobically

Digested Sludge

(No./100 milliliters)

Virus 2,500 - 70,000 100 - 1,000

Fecal Coliform Bacteriaa 1,000,000,000 30,000 - 6,000,000

Salmonella 8,000 3 - 62 

Ascaris lumbricoidesHelminth

 200 - 1,000 0 - 1,000

a

 Although not pathogenic, they are frequently used as indicators.

31
pathogens that may be present in sewage sludge and

pathogen and vector attraction reduction processes, see

other EPA documents (U.S. EPA, 1992a, 1994).

Following land application, bacterial pathogens generally die off to negligible numbers (99 percent die-off) in

12 days (Salmonella sp.) or 18 days (fecal coliform) at

a temperature of 15°C (EPA, 1992b, based on EPA,

1987). Viruses commonly survive a maximum of 19 days

(surface application) at 15°C (EPA, 1987; U.S. EPA,

1992b). Protozoa will survive for only a few days (Kowal,

1983). Viable helminth ova densities in sewage sludge

applied to the surface of grassed plots are reduced by

more than 90 percent within 3 to 4 months; viable

helminth ova survive longer if sewage sludge is tilled into

the soil (Jakubowski, 1988). Generally, none of these

microorganisms will leach through the soil system to

pollute the receiving ground waters (Edmonds, 1979),

but instead will remain in the surface soils for the duration of their survival period. Where surface runoff occurs,

buffers should be used to filter out pathogens and prevent entry into receiving water bodies.

4.8 Nutrients

Nutrients present in sewage sludge, such as nitrogen

(N), phosphorus (P), and potassium (K), among others,

are essential for plant growth and endow sewage sludge

with its fertilizing properties. Nutrient levels are key determinants of sewage sludge application rates. Excessive nutrient levels due to high sludge application rates

can result in environmental contamination of ground

water and surface water and should be avoided. The

Part 503 regulation requires that bulk sewage sludge be

applied to land at the agronomic rate for nitrogen at the

application site.1

Table 4-4 shows levels of nutrients typically present in

sewage sludge. Nutrient levels, however, particularly

nitrogen levels, can vary significantly, and thus analysis

should be conducted on the actual sewage sludge being

considered for land application. Typically, nutrient levels

in sewage sludge are considerably lower than those in

commercial fertilizers, especially K, which is usually less

than 0.5 percent in sewage sludge (Table 4-4). Thus,

supplemental fertilization will usually be needed along

with sewage sludge to promote optimum vegetative

growth. More sewage sludge can be applied for additional nutrients as long as the Part 503 CPLRs are not

exceeded, or the Part 503 pollutant concentration limits

are met (see Chapter 3). When the pollutant concentration limits are met, the application rate for the sewage

sludge is not impacted by the amount of each pollutant

in the sewage sludge.

4.8.1 Nitrogen

Nitrogen (N) may be present in sewage sludge in an

inorganic form, such as ammonium (NH4) or nitrate

(NO3), or in an organic form. The form in which N is

present in sewage sludge is a key factor in determining

how much N is available to plants, as well as the potential for N contamination of ground water. Generally, inorganic N as NO3 is the most water-soluble form of N,

and therefore is of the most concern for ground-water

contamination because of its high mobility in most soil

types. Inorganic N in the form of NH4 can readily volatilize as ammonia (NH3) when sewage sludge is applied

to the soil surface rather than incorporated or injected,

and thus may not be available to plants. Organic N must

be decomposed by soil microorganisms, or mineralized

to inorganic NH4 and NO3, before this form of N is

available for plants to use. Therefore, organic N can be

considered a slow-release form of N.

The concentrations of organic and inorganic N in sewage sludge are affected by the type of sludge treatment

and handling processes used. Most of the organic N in

sewage sludge is associated with the sludge solids, and

thus organic N levels are not appreciably altered by

sludge dewatering or drying procedures. In contrast, the

water-soluble inorganic forms of N and their concentrations will decrease dramatically during dewatering (e.g.,

drying beds, centrifuges, presses). Some heat or air

drying processes or lime treatment will reduce NH4 because of NH3 volatilization, but will not affect NO3 levels.

1

 The agronomic rate is defined in Part 503 as the sewage sludge

application rate designed to provide the amount of nitrogen needed

by the crop or vegetation grown and to minimize the amount of

nitrogen in the sewage sludge that passes below the root zone of

the crop to the ground water.

Table 4-4. Nutrient Levels Identified in Sewage Sludge

(Sommers, 1977; Furr et al., 1976)a

Percentb

Nutrient

Number of

Samples Range Median Mean

Total N 191 <0.1-17.6 3.30 3.90c

NH4

+-N 103 5x10-4-6.76 0.09 0.65

NO3

−-N 43 2x10-4-0.49 0.01 0.05

P 189 <0.1-14.3 2.30 2.50

K 192 0.02-2.64 0.30 0.40

Na 176 0.01-3.07 0.24 0.57

Ca 193 0.1-25.0 3.9 4.9

Fe 165 <0.1-15.3 1.1 1.3

a

 Data are from numerous types of sludge in 15 states: Michigan,

New Hampshire, New Jersey, Illinois, Minnesota, Ohio, California,

Colorado, Georgia, Florida, New York, Pennsylvania, Texas, Washington, and Wisconsin. b

 Dry solids basis.

c

 It is assumed that 82 percent of the total N is organic N. So: organic

N + NH4 + NO3 = TN, or: 3.2 + 0.65 + 0.05 = 3.90.

32
Aerobic conditions facilitate microbial conversion of

other N species to the mobile NO3 form; conversely,

anaerobic conditions inhibit conversion of NH4 to NO3

by oxidation. Usually, over 90 percent of the inorganic N

in sewage sludge will be in the form of NH4 unless

aerobic conditions have prevailed during sludge treatment. For most liquid sewage sludge collected from an

anaerobic digester, essentially all the inorganic N will be

present as NH4, constituting from 25 to 50 percent of the

total N. The NH4 concentration in the liquid phase of

sludge is relatively constant at a specific treatment plant,

although treatment process such as dewatering can

substantially lower the NH4 content to less than 10

percent of the total N.

Because the inorganic N content of sewage sludge is

significantly influenced by sludge handling procedures, N

analysis should be conducted on the actual sewage sludge

that is land applied. The amount of inorganic N mineralized

in soils is affected by the extent of sludge processing (e.g.,

digestion, composting) within the sewage treatment plant

and will generally be less for well stabilized sludge.

The organic N content of sewage sludge can range from

1 to 10 percent on a dry weight basis. Organic N compounds found in sludge are primarily amino acids, indicating the presence of proteinaceous materials (Ryan et

al., 1973; Sommers et al., 1972). After application to

soils, microbes in the soil will decompose the organic N

compounds in sewage sludge, resulting in release of

NH4

+

, which can then be assimilated by the crop or

vegetation being grown.

For a further discussion of nitrogen availability once

sewage sludge has been land applied, see Chapters 7,

8, and 9.

 4.8.2 Phosphorous, Potassium, and Other

Nutrients

Sewage sludge contains varying concentrations of other

macro- and micronutrients required for plant growth. Some

sludge constituents, such as phosphorous (P), calcium

(Ca), magnesium (Mg), and iron (Fe), readily form insoluble compounds with sludge solids and thus remain at

relatively high levels in sewage sludge (Table 4-4).

Other sewage sludge constituents, such as potassium

(K) and sodium (Na), are water-soluble and are discharged with the treated wastewater, unless special

advanced treatment processes are used to remove

them. Of the water-soluble constituents that do remain

in the sludge, dewatering of sludge (e.g., by centrifuges

or presses) will further reduce their concentrations in

sludge, while air or heat drying will result in increased

levels because these constituents are nonvolatile.

For a discussion of the influence of P, K, and nutrient

levels on sewage sludge application rates, see Chapters 7, 8 and 9.

4.9 Metals

Sewage sludge may contain varying amounts of metals;

at low concentrations in soil, some of these metals are

nutrients needed for plant growth and are often added to

inorganic commercial fertilizers. But at high concentrations, some metals may be toxic to humans, animals, and

plants. Based on an extensive risk assessment of metals

in sewage sludge, the Part 503 rule regulates 10 metals in

sewage sludge that is to be land applied, including:

• Arsenic

• Cadmium

• Chromium

• Copper

• Lead

• Mercury

• Molybdenum

• Nickel

• Selenium

• Zinc

The Part 503 risk assessment found that other metals

do not pose potential health or environmental risks at

land application sites. EPA’s 1990 National Sewage

Sludge Survey (NSSS) analyzed samples of 412 pollutants or analytes from 177 POTWs using at least secondary treatment processes, including the 10 metals

regulated by Part 503 for land application, as shown in

Table 4-5. Chapter 3 discusses the Part 503 pollutant

limits for these 10 metals. Based on the NSSS survey,

EPA estimates that only approximately 2 percent (130

POTWs) of the 6,300 POTWs affected by Part 503

Table 4-5. Mean Concentrations of Metals in Sewage Sludge

Compared to Part 503 Ceiling Concentration

Limits (Adapted From U.S. EPA, 1990)

Metal

Mean Concentration

(mg/kg, DW)

Part 503 Pollutant 

Ceiling Concentration 

Limits (mg/kg, DW)

Arsenic 9.9 75

Cadmium 6.94 85

Chromium 119 3,000

Copper 741 4,300

Lead 134.4 840

Mercury 5.2 57

Molybdenum 9.2 75

Nickel 42.7 420

Selenium 5.2 100

Zinc 1,202 7,500

33
would not meet the regulation’s “ceiling concentrations”

for metals, the minimal requirement for land application.

Metal concentrations in sewage sludge in large part

depend on the type and amount of industrial waste

discharged into the wastewater treatment system. Because metals are generally insoluble, they usually are

present at higher levels in sewage sludge than in wastewater, and dewatering of sewage sludge has a minimal

impact on reducing metal concentrations in sewage

sludge destined for land application. Pretreatment of

industrial wastewater discharged to a sewerage system

has been effective in reducing the metals content of

sewage sludge generated at treatment works.

4.10 Organic Chemicals

Sewage sludge may also contain synthetic organic

chemicals from industrial wastes, household products,

and pesticides. Most sewage sludge contains low levels

of these chemicals and does not pose a significant

human health or environmental threat. Part 503 does not

regulate organic chemicals in sewage sludge because

the organic chemicals of potential concern have been

banned or restricted for use in the United States; are no

longer manufactured in the United States; are present

at low levels in sewage sludge based on data from EPA’s

1990 NSSS; or because the limit for an organic pollutant

identified in the Part 503 risk assessment is not expected to be exceeded in sewage sludge that is used or

disposed (U.S. EPA, 1992b).

4.11 Hazardous Pollutants (If Any)

Sewage sludge is not included on a list of specific wastes

determined to be hazardous by EPA, nor does available

data suggest that sewage sludge is likely to exhibit characteristics of a hazardous waste, which include ignitability,

corrosivity, reactivity, or toxicity. The non-hazardous nature

of sewage sludge, however, cannot be assumed.

Although sewage sludge conceivably could exhibit the

characteristics of ignitability, corrosivity, or reactivity, most

concerns about sewage sludge have focused on toxicity.

Few, if any, sewage sludges will exhibit the toxicity characteristic (55 FR 11838). If, however, factors are present

indicating a possible toxicity problem (e.g., the treatment

works receives significant loadings of pollutants covered

by the test for toxicity) and the treatment works does not

have current data showing that the sludge is not hazardous, it is advisable for the treatment works to test the

sewage sludge for toxicity (U.S. EPA, 1990).

The test for toxicity is the Toxicity Characteristic Leaching Procedure (TCLP). This test can be used for both

sewage sludge and domestic septage. For the TCLP

test, concentrations of pollutants in a TCLP sewage

sludge extract are compared to regulatory levels for

toxicity. Table 4-6 lists the toxicity characteristic

Table 4-6. Analytical Classification and Limits for TCLP Constituents

Constituent Limit, mg/L

Pesticides

Chlordane 0.03

Endrin 0.02

Heptachlor 0.008

Lindane 0.4

Methoxychlor 10.0

Toxaphene 0.5

Herbicides

2,4-D 10.0

2,4,5-TP Silvex 1.0

Volatiles

Benzene 0.5

Carbon tetrachloride 0.5

Chlorobenzene 100.0 

Chloroform 6.0

1,2-Dichloroethane 0.5

1,1-Dichloroethylene 0.7

Methyl ethyl ketone 200.0 

Tetrachloroethylene 0.7

Toluene 1000.0 

Trichloroethylene 0.5

Vinyl chloride 0.2

Semivolatiles

o-Cresol 200.0 

m-Cresol 200.0 

p-Cresol 200.0 

1,2-Dichlorobenzene 300.0 

1,4-Dichlorobenzene 7.5

2,4-Dinitrotoluene 0.1

Hexachlorobenzene 0.02

Hexachlorobutadiene 0.5

Hexachloroethane 3.0

Nitrobenzene 2.0

Pentachlorophenol 1.0

2,4,5-Trichlorophenol 400.0 

2,4,6-Trichlorophenol 2.0

Metals

Arsenic 5.0

Barium 100.0 

Cadmium 1.0

Chromium 5.0

Lead 5.0

Mercury 0.2

Selenium 1.0

Silver 5.0

34
pollutants and their regulatory levels. If the concentrations of pollutants in the extract meet or exceed

these regulatory levels, the wastes are classified as

hazardous. If a sewage sludge or domestic septage

extract is deemed hazardous, land application would not

be allowed. Studies conducted by EPA’s Office of Solid

Waste in 1985-86 found that none of the sewage sludge

samples tested had TCLP extract concentrations that

exceeded the (then proposed) regulatory levels. For

most pollutants, except metals, levels were non-detectable (U.S. EPA, 1993a).

4.12 Types of Sewage Sludge

The characteristics of sewage sludge described above

will vary depending on the type of sewage sludge generated, as discussed below.

4.12.1 Primary Sewage Sludge

Primary sewage sludge—sludge that is the result of

primary wastewater treatment and has not undergone

any sludge treatment process—usually contains from 93

to 99.5 percent water, as well as solids and dissolved

substances that were present in the wastewater or were

added during the wastewater treatment process (U.S.

EPA, 1984). Primary wastewater treatment removes the

solids (sludge) that settle out readily from the wastewater. Usually the water content of this sludge can be easily

reduced by thickening or dewatering.

4.12.2 Secondary Sewage Sludge

Secondary wastewater treatment generally involves a

primary clarification process followed by biological treatment and secondary clarification (U.S. EPA, 1990).

Sewage sludge generated by secondary wastewater

treatment processes, such as activated biological systems and trickling filters, has a low solids content (0.5

percent to 2 percent) and is more difficult to thicken and

dewater than primary sewage sludge.

4.12.3 Tertiary Sewage Sludge

Tertiary sewage sludge is produced by advanced wastewater treatment processes such as chemical precipitation and filtration. Chemicals used in advanced

wastewater treatment processes, such as aluminum,

iron, salts, lime, or organic polymers, increase sludge

mass and usually sludge volume. Generally, if lime or

polymers are used, the thickening and dewatering characteristics of sludge will improve, whereas if iron or

aluminum salts are used, the dewatering and thickening

capacity of the sludge will usually be reduced.

4.12.4 Domestic Septage

Domestic septage is considered sewage sludge by the

Part 503 regulation and is defined and discussed in

Chapter 11. Table 4-7 shows some of the characteristics

of domestic septage. Domestic septage may foam and

generally has a strong odor (U.S. EPA, 1978). Settling

properties are highly variable. Some domestic septage

settles readily to about 20 to 50 percent of its original

volume, while others show little settling (U.S. EPA, 1979).

4.13 Effects of Wastewater and Sludge

Treatment Processes on Sewage

Sludge Characteristics

The effects of wastewater and sludge treatment processes on sewage sludge characteristics have been

discussed above as they pertain to specific sludge

parameters. This section focuses on the broader effects of treatment on sewage sludge characteristics,

highlighting the variable nature of treated sludge and

thus the need for site-specific sludge characterization.

Table 4-1 lists the various types of treatment processes, a number of which can be used to meet the

Part 503 pathogen or vector attraction reduction requirements (see Chapter 3). Table 4-8 shows nutrient

levels found in sewage sludge subjected to different

treatment processes. EPA’s Process Design Manual

for Sludge Treatment and Disposal (U.S. EPA, 1979)

provides further information on sludge treatment

technologies.

Sewage sludge is virtually always treated by a stabilization process prior to land application. Stabilization reduces the volume of raw sludge by 25 to 40 percent

because much of the volatile solids are degraded to

Table 4-7. Chemical and Physical Characteristics of

Domestic Septage (U.S. EPA, 1993b)

Parameter

Concentration, mg/kg

(dry weight basis)

Arsenic 4

Cadmium 3

Chromium 14 

Copper 140 

Lead 35 

Mercury 0.15

Molybdenum -

Nickel 15 

Selenium 2

Zinc 290 

Nitrogen as N 2%

Phosphorus as P <1%

pH 6-7

Grease 6-12%

Biochemical oxygen demand (BOD5) 6,480 mg/L

Total solids (as normally spread) 3.4%

35
carbon dioxide, methane, or other end products. This

decomposition of the organic matter in the sludge and

the subsequent release of carbon dioxide, ammonium, hydrogen sulfide, and phosphate result in lower

levels of organic carbon (C), nitrogen (N), sulfur (S),

and phosphorous in the stabilized sludge than was

present in the raw sludge entering the stabilization

unit. Stabilization processes include aerobic and anaerobic digestion and composting, among others. The

actual amounts of stabilized sludge produced in a

treatment works depends on operational parameters

(e.g, temperature, mixing, detention time) of the stabilization process used.

Composting of sewage sludge results in further decreases in the organic constituents. If the sludge is

mixed with a bulking agent (e.g., wood chips) during composting to facilitate aeration and rapid stabilization, some

of the bulking agent will remain in the compost (even

if screened), resulting in dilution of sludge components

(e.g., nutrients, metals). The extensive biological activity

that occurs during composting results in further decreases in the organic N, C, and S content of the sludge.

In general, the organic N content of sludge decreases

in the following order: raw, primary or waste activated,

digested, and composted.

Wastewater and sewage sludge treatment processes

often involve the addition of ferric chloride, alum, lime,

or polymers. The concentration of these added elements increase their concentration in the resultant

sludge. In addition, the added compound can have

other indirect effects on sludge composition. For example, alum precipitates as aluminum hydroxides, which

can subsequently adsorb phosphorus and coprecipitate

with trace metals such as cadmium. Lime (calcium

oxide or hydroxide) used as a sludge stabilization agent

will ultimately precipitate in sludge as calcium carbonate, which also can retain phosphorus and metals. Lime

addition also may result in losses of ammonia through

volatilization.

Table 4-8. Nutrient Levels in Sewage Sludge From Different Treatment Processes (Sommers, 1977)a

Nutrient

Sludge

Treatment 

Processb No. of

Samples Range Median Mean

Organic C (%) Anaerobic

Aerobic

Other

All

 31

 10

 60

101

18-39 

27-37 

 6.5-48 

6.5-48 

 26.8

 29.5

 32.5

 30.4

 27.6

 31.7

 32.6

 31.0

Total N (%) Anaerobic

Aerobic

Other

All

 85

 38

 68

191

0.5-17.6 

0.5-7.6 

<0.1-10.0 

<0.1-17.6 

 4.2

 4.8

 1.8

 3.3

 5.0

 4.9

 1.9

 3.9

NH4

+-N (mg/kg) Anaerobic

Aerobic

Other

All

 67

 33

 3

103

120-67,600

 30-11,300

 5-12,500

 5-67,600

1,600 

400 

 80

920 

9,400 

950 

4,200 

6,540 

NO3

−-N (mg/kg) Anaerobic

Aerobic

Other

All

 35

 8

 3

 45

 2-4,900

7-830 

—

 2-4,900

 79

180 

—

149 

520 

300 

780 

490 

Total P (%) Anaerobic

Aerobic

Other

All

 86

 38

 65

189

0.5-14.3 

1.1-5.5 

<0.1-3.3 

<0.1-14.3 

 3.0

 2.7

 1.0

 2.3

 3.3

 2.9

 1.3

 2.5

K (%) Anaerobic

Aerobic

Other

All

 86

 37

 69

192

0.02-2.64 

0.08-1.10 

0.02-0.87 

0.02-2.64 

 0.30

 0.39

 0.17

 0.30

 0.52

 0.46

 0.20

 0.40

Na (%) Anaerobic

Aerobic

Other

All

 73

 36

 67

176

0.01-2.19 

0.03-3.07 

0.01-0.96 

0.01-3.07 

 0.73

 0.77

 0.11

 0.24

 0.70

 1.11

 0.13

 0.57

Ca (%) Anaerobic

Aerobic

Other

All

 87

 37

 69

193

1.9-20.0 

0.6-13.5 

0.12-25.0 

0.1-25.0 

 4.9

 3.0

 3.4

 3.9

 5.8

 3.3

 4.6

 4.9

a

 Concentrations and percent composition are on a dried solids basis.

b

 “Other” includes lagooned, primary, tertiary, and unspecified sludges. “All” signifies data for all types of sludges.

36
4.14 Effects of Pretreatment and

Pollution Prevention Programs on

Sewage Sludge Characteristics

EPA first established pretreatment requirements (40

CFR Part 403) in 1978. Pretreatment programs require

industries to limit the concentrations of certain pollutants

in wastewater discharged to a treatment works, including heavy metals and organic chemicals.

In addition to pretreatment programs, pollution prevention programs designed to reduce or eliminate pollution

are often developed as a joint effort by industry and

government and are undertaken voluntarily by a

company. The quality of sewage sludge has continually improved over the years, and many regulators,

researchers, and treatment works managers believe

that pretreatment and pollution prevention programs

have been significant factors in achieving this improvement. For example, levels of cadmium, chromium, and

lead have decreased since the 1970s, as shown by data

from EPA’s 1982 “40 City Study” (U.S. EPA, 1982) and

1990 NSSS (Shimp et al., 1994).

4.15 References

When an NTIS number is cited in a reference, that 

document is available from: 

 National Technical Information Service

 5285 Port Royal Road

 Springfield, VA 22161

 703-487-4650

Edmonds, R. 1979. Microbiological characteristics of dewatered

sludge following application to forest soils and clearcut areas. In:

Sopper, W., and S. Kerr, eds. Application of municipal sewage

effluent and biosolids on forest and disturbed land. University

Park, PA: Pennsylvania State University Press.

Furr, A., A. Lawrence, S. Tong, M. Grandolfo, R. Hofstader, C. Bache,

W. Gutenmann, and D. Lisk. 1976. Multi-element and chlorinated

hydrocarbon analysis of municipal sewages of American cities.

Environ. Sci. Technol. 10:683-687.

Jakubowski, W. 1988. Ascaris ova survival in land application conditions. EPA Administrator’s Item Deliverable No. 2799 (May 1988).

Kowal, N. 1983. An overview of public health effects. In: Page, A., T.

Gleason, III, J. Smith, Jr., I. Iskandar, and L. Sommers, eds. Proceedings of the 1983 Workshop on Utilization of Municipal Wastewater and

Sludge on Land. Riverside, CA: University of California. pp. 329-394.

Ryan, J., D. Keeney, and L. Walsh. 1973. Nitrogen transformations

and availability of an anaerobically digested sewage sludge in soil.

J. Environ. Quality 2:489-492.

Sagik, B., B. Moore, and C. Forber. 1979. Public health aspects related

to the land application of municipal sewage effluents and sludges.

In: Sopper, W.E., and S.M. Kerr, eds. Utilization of municipal sewage

effluent and sludge on forest and disturbed land. University Park,

PA: Pennsylvania State University Press. pp. 241-263.

Shimp, G., K. Hunt, S. McMillian, and G. Hunter. 1994. Pretreatment

raises biosolids quality. Environ. Protection 5(6).

Sommers, L. 1977. Chemical composition of sewage sludges and

analysis of their potential use as fertilizers. J. Environ. Quality

6:225-239.

Sommers, L., D. Nelson, J. Yahner, and J. Mannering. 1972. Chemical composition of sewage sludge from selected Indiana cities.

Oroc. Indiana Acad. Sci. 82:424-432.

U.S. EPA. 1994. A plain English guide to the EPA 503 biosolids rule.

EPA/832/R-93/003 (June). Washington, DC.

U.S. EPA Regions VIII and X. 1993a. Biosolids management handbook

for small to medium size POTWs. Denver, CO, and Seattle, WA.

U.S. EPA. 1993b. Domestic septage regulatory guidance. EPA/832/B92/005. Washington, DC.

U.S. EPA. 1992a. Control of pathogens and vector attraction in sewage sludge. EPA/625/R-92/013. Cincinnati, OH.

U.S. EPA. 1992b. Technical support document for land application of

sewage sludge, Vol. I. EPA/822/R-93900/9 (NTIS PB93110583).

Washington, DC.

U.S. EPA. 1992c. Technical support document for reduction of pathogens and vector attraction in sewage sludge. NTIS PB93110609.

Washington, DC.

U.S. EPA. 1990. National Sewage Sludge Survey: Availability of information and data, and anticipated impacts on proposed regulations. Fed. Reg. 55(218).

U.S. EPA. 1987. Survival and transport of pathogens in sludgeamended soil: A critical literature review. EPA/600/2-87/028. Cincinnati, OH.

U.S. EPA. 1984. Use and disposal of municipal wastewater sludge.

EPA/625/10-84/003. Cincinnati, OH.

U.S. EPA. 1982. Fate of priority pollutants in publicly owned treatment

works. EPA/440/1-82/303. Washington, DC.

U.S. EPA. 1979. Process design manual for sludge treatment and

disposal. EPA/625/1-79/011. Cincinnati, OH.

U.S. EPA. 1978. Treatment and disposal of septic tank sludges: A

status report. Distributed at the Seminar on Small Wastewater

Facilities. Cincinnati, OH.

37
Chapter 5

Site Evaluation and Selection Process

5.1 General

The process of planning a sewage sludge land application project begins with the collection and assessment

of basic data on sludge characteristics. The sludge characteristics in conjunction with estimated application

rates can then be compared to applicable federal, state,

and local regulations for an initial assessment of sewage

sludge suitability for any of the land application practices

discussed in Chapter 2. The public’s perception and

acceptance of such a proposed project, as well as land

availability, transportation modes, and climatic conditions, must all be considered and evaluated to determine

the feasibility of the proposed program. 

The careful identification, evaluation, and ultimate selection of land application sites can prevent future environmental problems, reduce monitoring requirements,

minimize overall program costs, and moderate or eliminate adverse public reaction. Poor site selection and

management practices in the past have resulted in environmental problems and public resistance. 

Section 5.2 gives an overview of key requirements in the

Part 503 regulation that affect site selection for land

application of sewage sludge. Figure 5-1 provides an

overview of a six-step process for identifying the best

sewage sludge land application practice and the best

site(s) for land application of sewage sludge. Sections

5.4 though 5.8 describe each of the six steps in more

detail, and Section 5.9 provides an example of the site

selection procedures that can be used for a typical

medium-sized community.

5.2 Part 503 Requirements

The Part 503 rule contains several provisions that must

be considered during site selection for land application

of sewage sludge. These provisions are discussed

briefly below and are explained further in Chapter 3.

Some state and local governments have developed additional or more stringent regulations; therefore, it is

important to check with state and local regulatory and

permitting agencies where the proposed project is located to determine what requirements apply.

5.2.1 Protection of Surface Water and

Wetlands

Part 503 specifies that sewage sludge cannot be applied

to flooded, frozen, or snow-covered agricultural land,

forests, public contact sites, or reclamation sites in such

a way that it enters a wetland or other waters of the

United States, except as provided in a Section 402

(NPDES) or Section 404 (dredge and fill) permit. In

addition, sewage sludge cannot be applied to agricultural land, forests, or reclamation sites that are 10 meters or less from waters of the United States, unless

otherwise specified by the permitting authority. 

Other federal regulations also may apply to sewage

sludge application in wetlands. These include:

• Sections 401, 402, and 404 of the Clean Water Act

• The Rivers and Harbors Act of 1989

• Executive Order 11990, Protection of Wetlands

• The National Environmental Policy Act

• The Migratory Bird Conservation Act

• The Fish and Wildlife Coordination Act

• The Coastal Zone Management Act

• The Wild and Scenic Rivers Act

• The National Historic Preservation Act

Additional published information that may be useful includes USGS topographic maps, National Wetland Inventory maps, Soil Conservation Service (SCS) soil

maps, and wetland inventory maps prepared locally.

Some of the local U.S. Army Corps of Engineers District

Offices can provide a wetland delineation to indicate

whether all or some portion of a potential or actual land

application site is in a wetland. The state agency regulating activities in wetlands should also be asked to

inspect the area in question. The definition of a wetland

and the regulatory requirements for activities in wetlands may be different at the state level.

39
5.2.2 Protection of Threatened and

Endangered Species

Under Part 503, sewage sludge may not be applied to

land if it is likely to adversely affect a threatened or

endangered species listed under Section 4 of the Endangered Species Act or the designated critical habitat

of such a species. The Threatened and Endangered

Species List can be obtained from the U.S. Fish and

Wildlife Service’s (FWS’s) Publications Office in Washington, DC. Critical habitat is defined as any place where

a threatened or endangered species lives and grows

during any stage of its life cycle. 

Any direct or indirect action (or the result of any direct

or indirect action) in a critical habitat that diminishes the

likelihood of survival and recovery of a listed species is

considered destruction or adverse modification of a critical habitat. Individuals may contact the Endangered Species Protection Program in Washington, DC. or Fish and

Wildlife Service Field Offices for more information about

threatened and endangered species considerations in

their area. State departments governing fish and game

also should be contacted for specific state requirements.

5.2.3 Site Restrictions

Restrictions for the harvesting of crops and turf, grazing

of animals, and public access (see Chapter 3) also must

be met when sewage sludge that meets the Part 503

Class B pathogen requirements is land applied.

Phase ll Site Evaluation (Section 5.6 and Chapter 6)

Selection of Land Application Practice (Section 5.7)

Final Site Selection (Section 5.8)

Site Screening (Section 5.5.4)

Site Physical Characteristics (Section 5.5.3)

Land Use (Section 5.5.2)

Existing Information Sources (Section 5.5.1)

Phase l Site Evaluation and Site Screening (Section 5.5)

Assess Sewage Sludge Transport Modes and Their 


Feasibility (Section 5.4.4)

Estimate Land Area Required for Sewage Sludge 


Application, and Availability of Land Area Neccessary 


(Section 5.4.3)

Public Participation (Section 5.4.2)

Review Applicable Federal, State, and Local


Regulations and Guidelines for Land Application of


Sewage Sludge (Section 5.4.1)

Preliminary Planning (Section 5.4)

Determine Sewage Sludge Characteristics (Chemical,


Biological, and Physical, Chapter 4)

Figure 5-1. Simplified planning steps for a sewage sludge land application system.

40
5.3 Planning and Selection Process

As shown in Figure 5-1, this manual suggests a phased,

six-step planning and site selection approach.

5.4 Preliminary Planning

Careful preliminary planning will help minimize delays

and expenses later on in the process by identifying legal

constraints (Section 5.4.1) and obtaining public input

early in the process (Section 5.4.2). A preliminary estimate of land area requirements for different land application practices (Section 5.4.3) and a preliminary

identification of feasible sewage sludge transportation

options (Section 5.4.4) helps focus the Phase I site

evaluation and site screening process (Section 5.5). The

transportation assessment is especially important for

defining the geographic search area for potential land

application sites.

5.4.1 Institutional and Regulatory Framework

All current federal, state, county, and municipal regulations and guidelines should be reviewed during the

preliminary planning process. Depending on local procedure, permits may be required from both state and

local regulatory agencies. Figure 5-2 shows the agencies that have jurisdiction over land application of sewage sludge. Federal requirements under the Part 503

rule are described in detail in Chapter 3 of this manual.

5.4.2 Public Participation

Public participation is critical during the early stages of

planning a land application project. Most involvement

should come at the beginning of the planning process

when public input has the greatest potential to shape the

final plan. This early involvement helps determine the

limits to public and political acceptability of the project.

During this phase, the public plays a constructive, as

opposed to a reactive, role in decision-making.

Site selection generally involves a preliminary screening

of numerous potential sites after which several sites are

selected for more detailed investigation. These selected

sites should be subjected to intense public scrutiny. It is

at this point that public participation can play a particularly formative role in determining the final site and

design and operation procedures.

Most public interest and involvement—including the

most vocal and organized protests—occur during the

site selection stage. Therefore, the major thrust of the

public participation program should come during this

stage, with a particular emphasis on two-way communication using such avenues as public meetings, workshops, and radio talk shows.

Chapter 12 provides a detailed discussion of how to

design and implement a public participation program for

a land application project.

5.4.3 Preliminary Land Area Requirements

A precise estimate of the land area required for sewage

sludge application should be based on design calculations provided in Chapters 7, 8, and 9 for the land

application practice under consideration. However, for

preliminary planning, a rough estimate of the land application area which might be necessary can be obtained

from Table 5-1. (Note that different practices may not

necessarily involve repeated annual applications.) 

As an example, assume that the project is intended to

land apply 1,000 t (1,100 T), dry weight, of sewage

sludge annually. Using the typical rates shown in Table 5-1, a very rough estimate of the area required

for agricultural land application would be 90 ha (220

ac), plus additional area required, if any, for buffer zones, sludge storage, etc. For a one-time application of 1,000 t of sewage sludge at a land reclamation

site, the typical values shown in Table 5-1 indicate that

9 ha (22 ac) would be required.

5.4.4 Sewage Sludge Transport Assessment 

Transport can be a major cost of a land application

project, and requires a thorough analysis. This section

is intended only to provide a brief summary of the alternatives that may be considered during the preliminary

planning phase.

Sewage sludge can be transported by truck, pipeline, or

rail. In certain instances, combined transport methods

(e.g., pipeline-truck) are also used. The choice of a

transportation method depends on the type of land selected, the volume and solids content of the sewage sludge,

and the distance to and number of destination points.

The first consideration is the nature of the sewage

sludge itself. As shown in Table 5-2, sewage sludge is

classified for handling/transport purposes as either liquid, sludge cake, or dried, depending on its solids

content. Only liquid sludge can be pumped and transported by pipeline. Pipeline transport can be cost

effective for long-distance pumping of liquid sludge

(usually less than 8 percent solids) but has been used

for sludge up to 20 percent solids over very short distances. If liquid sludge is transported by truck or rail,

closed vessels must be used, e.g., tank truck, railroad tank cars, etc. Sludge cake can be transported

in watertight boxes, and dry sludge can be transported in open boxes (e.g., dump trucks).

Trucks and pipelines are the most common form of

transport. Rail transport also is used in the United

States. An example is rail shipment of sludge from New

York to Texas.

41
Truck transport allows greater flexibility than any other

transport method. Destinations can be changed with

little advance notice, and the sludge can be distributed

to many different destinations. If trucks must be routed

along residential or secondary streets, public concern

about congestion and the risk of sludge spills must be

considered. Most land application systems use truck

transport, either alone or after sludge transport by pipeline or rail to an intermediate storage facility. Liquid

sludge of up to 10 percent solids concentration (depending on its viscosity) can be transported in tank trucks.

Dewatered sludge with a greater than 10 percent solids

concentration can usually be transported in open trucks

with watertight seals if precautions are taken to prevent

spillage. Dried and composted sludge with approximately 50 percent or greater solids concentration can be

transported without watertight seals or splash guards

(U.S. EPA, 1984).

The desirable limit for a truck haul distance is about 25

to 40 km (15 to 25 mi) one way. For low cost land

application of liquid sludge, the land must generally be

within about a 16-km (10-mi) radius of the treatment

plant. Mechanically dewatered sludge can generally be

economically transported to a site up to about 22 km (20 mi).

Air-dried sludges, which have solids concentrations in excess of 55 to 60 percent, can be economically transported

a greater distance. In evaluating transportation costs,

Figure 5-2. Institutional framework (adapted from Deese et al., 1980).

42
the cost of dewatering must be weighed against the cost

savings that can result from transporting a drier sludge

(U.S. EPA, 1984).

Tables 5-3 and 5-4 present some practical considerations for hauling sludge. Table 5-5 provides a rating of

transport modes in terms of reliability, staffing needs,

energy requirements, and costs. For a detailed discussion of sludge transport, see Chapter 14.

5.5 Phase I Site Evaluation and Site

Screening

A Phase I site evaluation uses the information obtained

during preliminary planning, namely the estimate of preliminary land area requirements (Section 5.4.3) and the

results of the transportation assessment (Section 5.4.4),

to identify potential land application sites. Existing information sources (Section 5.5.1) are used to identify multiple sites considering land use (Section 5.5.2) and

physical characteristics (Section 5.5.3) within the area

that sewage sludge can feasibly be transported. Site

screening allows elimination of unsuitable areas due to

physical, environmental, social, or political reasons

(Section 5.5.4), and identification of sites for more detailed

Phase II site evaluation (Section 5.6 and Chapter 6).

5.5.1 Existing Information Sources 

Sources of information on land characteristics, cropping

patterns, and other relevant data in the geographic

search area include: 

• U.S. Department of Agriculture - Consolidated Farm

Service Agency, Natural Resources Conservation

Table 5-2. Sewage Sludge Solids Content and Handling

Characteristics

Sludge Type

Typical

Solids Content (%)

Handling/

Transport Methods

Liquid 1 to 10 Gravity flow, pump,

pipeline, tank transport

Sludge cake (“wet”

solids)

10 to 30 Conveyor, auger, truck

transport (watertight

box)

Dried 50 to 95 Conveyor, bucket,

truck transport (box)

Table 5-1. Preliminary Estimates of Sewage Sludge Applications (Dry Weight) for Different Types of Land

Reported Range of

Application Rates Typical Rate

Land Type Time Period of Application

t/ha T/ac t/ha T/aca

Agricultural Land Annual or twice annually 2-70 1-30 10 5

Forest Land Annually, or at 3-5 year intervals 10-220 4-100 18 8

Land Reclamation Site One time 7-450 3-200 112 50

a

t = metric tonnes

 T = English tons (short)

Table 5-3. Transport Modes for Sewage Sludge

Sewage Sludge Type Transportation Considerations

Liquid Sludge

Vehicles:

 Tank Truck Capacity - up to maximum load allowed on road, usually 6,600 gal maximum. Can have gravity

or pressurized discharge. Field trafficability can be improved by using flotation tires at the cost of

rapid tire wear on highways.

 Farm Tank Wagon and Tractor Capacity - 800 to 3,000 gal. Principal use would be for field application.

Pipeline Need minimum velocity of 1 fps to keep solids in suspension; friction decreases as pipe diameter

increases (to the fifth power); buried pipeline suitable for year-round use. High capital costs.

Rail Tank Car 100-wet-ton (24,000-gal) capacity; suspended solids will settle while in transit.

Semisolid or Dried Sludge

Truck Commercial equipment available to unload and spread on ground; need to level sludge piles if

dump truck is used. Spreading can be done by farm manure spreader and tractor.

Farm Manure Spreader Appropriate for small systems where nearby farmlands are accessible by a manure spreader.

Rail Hopper Car May need special unloading site and equipment for field application, although in many cases can

use conventional unloading equipment.

43
Service, Forest Service, and Cooperative State Research Education and Extension Service. 

• U.S. Geological Survey. 

• U.S. EPA. 

• U.S. Army Corps of Engineers. 

• Private photogrammetry and mapping companies. 

• State agricultural mining and geologic agencies. 

• State water resource agencies.

• State universities and local colleges.

• Local planning and health departments. 

• Local water conservation districts. 

• Ground water users (municipalities, water companies, individuals, etc.). 

• State land grant universities and water resource centers.

Section 5.5.3.5 identifies major sources for climatic data.

5.5.2 Land Use and Availability

Prevailing or projected land use often exerts a significant influence on site selection, as well as on acceptance of a particular sewage sludge land application

practice. It is necessary to determine both current and

future land use in assessing the land area potentially

suitable and/or available for sewage sludge application.

Important considerations include zoning compliance,

aesthetics, and site acquisition. 

5.5.2.1 Current Land Use

Current land use patterns will help identify areas where

land application of sewage sludge may be acceptable.

The local SCS and Agricultural Extension Service representatives have knowledge of local farming, forestry, mining, and other land use practices. The SCS will, in many

cases, have a comprehensive county soil survey with

aerial photo maps showing the land area. 

• Agricultural Lands. To a great extent, prevailing

farming practices dictate the acceptability of agricultural land application. Small land holdings in a nonagricultural community may limit application to this

type of land. An area devoted almost exclusively to

production of human food crops restricts the periods

when sewage sludge can be applied to land. Areas

Table 5-4. Auxiliary Facilities for Sewage Sludge Transport

(Culp et al., 1980)

Transport Mode

Truck Railroad Barge Pipeline

Liquid

 Loading storage No* Yes Yes Yes

 Loading equipment Yes Yes Yes Yes

 Dispatch office Yes Yes Yes NA†

 Dock and/or control

 building

NA NA Yes Yes

 Railroad siding(s) NA Yes NA NA

 Unloading equipment Yes Yes Yes NA

 Unloading storage# No Yes Yes Yes

Dewatered

 Loading storage Yes** Yes NA NA

 Loading equipment Yes Yes NA NA

 Dispatch office Yes Yes NA NA

 Dock and/or control

 building

NA NA NA NA

 Railroad siding(s) NA Yes NA NA

 Unloading equipment Yes Yes NA NA

 Unloading storage No No NA NA

* Storage required for one or two truckloads is small compared with

 normal plant sludge storage. †

 Not applicable.

#

 Storage assumed to be a part of another unit process.

** Elevated storage for ease of gravity transfer to trucks. 

Table 5-5. Evaluation of Sewage Sludge Transport Modes

(Culp et al., 1980)

Transport Mode Alternatives

Characteristics Truck Pipeline Railroad

Reliability and

Complexity1 131

Staffing Skills2 132

Staff Attention (Time)3 321

Applicability and

Flexibility4 132

Energy Used5 862

Costs

 Capital Investment Low High —

 Operation,

 Maintenance, and Labor

Fairly High Low —

 Overall6 — — Generally

High7

1

 1 = most reliable, least complex; 2 = intermediate; 3 = least

reliable, most complex. 2

 1 = least skills; 2 = intermediate; 3 = highest skills.

3

 Attention time increases with magnitude of number.

4

 1 = wide applicability (all types of sludge); 3 = limited applicability,

relatively flexible. 5

 1 = lowest; 8 = highest.

6

 Overall costs are a function of sludge quantities and properties

(percent solids), distance transported, and need for special 

storage loading and unloading equipment. 7 Rail costs would generally be in the form of freight charges; costs

could be lower for large volumes of sludge, or if long-distance rail

is less expensive than truck transport.

44
with a mixture of row crops, small grains, hay crops, and

pastures may allow sewage sludge application throughout much of the year, depending on farming cycles.

• Forest Lands. A consideration in sewage sludge application to forest lands is the potential need to control

public access for a period of time after sludge application. Therefore, the most desirable sites are often

those owned by or leased to commercial growers,

which already control public access. Publicly owned

forest land has been used for sewage sludge application, but may require interagency negotiations and

greater public education efforts than the use of privately owned land.

• Reclamation Sites. Potential reclamation sites are

relatively easy to identify in a particular local area.

Sewage sludge land application design is influenced

by the potential future use of the reclaimed land (i.e.,

agriculture, silviculture, parks, greenbelts, etc.). The

application of sewage sludge is often a one-time operation at reclamation sites rather than a repetitive

series of applications on the same site. It is therefore

necessary that (1) the mining or other operations will

continue to generate disturbed land to which sludge

can be applied, or (2) the reclamation area is of

sufficient size to allow a continuing sludge application

program over the design life of the project. State and

federal guidelines may dictate the criteria for sludge

applications and subsequent management.

• Public Contact Sites. Public contact sites such as

parks, golf courses, and cemeteries are good candidates for land application of sewage sludge. Because

municipalities often own these sites, a land application program may be easier to arrange at these sites

than at privately owned sites. Bagged sewage sludge

is often used at public contact sites having a small

land area. Regulatory requirements and other considerations for the use of sewage sludge at public

contact sites are explained in Chapter 10.

• Lawns and Home Gardens. Bagged sewage sludge

can be used like other fertilizers for lawns and home

gardens. Regulatory and other considerations for use

of sewage sludge on lawns and home gardens are

discussed in Chapter 10.

5.5.2.2 Future Land Use

Projected land use plans, where they exist, should be

included when considering sewage sludge land application. Regional planners and planning commissions

should be consulted to determine the projected use of

potential land application sites and adjacent properties.

If the site is located in or near a densely populated area,

extensive control measures may be needed to overcome concerns and minimize potential aesthetic problems that may detract from the value of adjacent

properties. Master plans for existing communities

should be examined. The rate of industrial and/or municipal expansion relative to prospective sites can significantly affect long-term suitability.

5.5.2.3 Zoning Compliance

Zoning and land use planning are closely related, and

zoning ordinances generally reflect future land use planning. Applicable zoning laws, if any, which may affect

potential land application sites should be reviewed concurrently with land use evaluations. Since it is unusual

that a community will have a specific area zoned for

sludge/waste storage, project proponents may need to

seek a zoning change for separate sewage sludge storage facilities.

5.5.2.4 Aesthetics

Selection of a land application site and/or sewage

sludge land application practice can be affected by community concern over aesthetics, such as noise, fugitive

dust, and odors. In addition to application site area

concerns, routes for sludge transport vehicles must be

carefully evaluated to avoid residential areas, bridge

load limitations, etc. Disruption of the local scenic character and/or recreational activities, should they occur,

may generate strong local opposition to a sewage

sludge management program. Every attempt must be

made to keep the application site compatible with its

surroundings and, where possible, enhance the beauty

of the landscape. Buffer zones are usually required to

separate sewage sludge application sites from residences, water supplies, surface waters, roads, parks,

playgrounds, etc.

5.5.2.5 Access

The preliminary sewage sludge transportation feasibility

assessment (Section 5.4.4) will narrow the geographic

search area for potential sites by focusing attention on

areas that are adjacent to or in the vicinity of existing

transportation corridors (e.g., roads, rail lines) for the

selected sewage sludge transportation modes. Areas

that are too distant for economic transport, or to which

access is restricted for other reasons (such as physical

barriers), can be eliminated from further consideration.

5.5.2.6 Site Acquisition

Application of sewage sludge to agricultural land can

often be accomplished without direct purchase or lease

of the land. Well-prepared educational and public participation programs early in the planning stages often

identify numerous farmers willing to participate in a land

application program. This type of arrangement may be

more acceptable to the public in some cases than purchasing land for sewage sludge land application. 

45
Several different contractual arrangements between

municipalities and landowners for agricultural land application have been successfully employed, including: 

• The municipality transports and spreads the sludge

at no expense to the landowner. 

• The municipality transports and spreads the sludge

and pays the landowner for the use of his land. 

• The landowner pays a nominal fee for the sewage

sludge and for the municipality to transport and

spread the sludge. This is most common for agricultural sites where local demand for sewage sludge as

a fertilizer or soil conditioner exists. 

• The municipality hauls the sludge and the landowner

spreads it. 

• The landowner hauls and spreads the sludge.

A written contract between the landowner and the sewage sludge preparer and/or applier is highly recommended. In some instances, the preparer/applier will be

the municipality; in other cases, it will be a private

preparer/applier who is transporting and spreading for

the municipality. The Part 503 rule contains requirements for both preparers and appliers (see Chapter 3).

The principal advantage of a written contract is to ensure

that both parties understand the agreement prior to

applying the sewage sludge. Often, oral contracts are

entered with the best of intentions, but the landowner

and preparer/applier have differing notions of the rights

and obligations of each party. In some cases, the contract may serve as evidence in disputes concerning the

performance of either the preparer/applier or the landowner. Suggested provisions of contracts between the

applier and landowner are shown in Table 5-6. 

The use of land without purchase or lease may also be

applicable for land application of sewage sludge to forested lands and reclamation sites. Direct purchase or

lease, however, may be necessary for large-scale sewage sludge management systems regardless of the type

of land at which sewage sludge is applied. In these

instances, site acquisition represents a major cost in the

implementation of the land application program. 

5.5.3 Physical Characteristics of Potential Sites

The physical characteristics of concern are: 

• Topography

• Soil permeability, infiltration, and drainage patterns

• Depth to ground water

• Proximity to surface water

The planner/designer should review federal and state

regulations or guidelines that place limits on these

physical characteristics of application sites. Chapter 6

addresses site physical characteristics in more detail.

This section focuses on information that can usually be

obtained from existing topographic and soil maps for the

purpose of identifying sites where more detailed investigations may be justified.

5.5.3.1 Topography

Topography influences surface and subsurface water

movement, which affects the amount of potential soil

erosion and surface water runoff containing applied

sewage sludge. These considerations have been factored into the pollutant limits established in the Part 503

regulation. Topography also can indicate the kinds of soil

to be found on a site. 

Quadrangle maps published by the U.S. Geological Survey may be useful during preliminary planning and

screening to estimate slope, local depressions or wet

areas, rock outcrops, regional drainage patterns, and

water table elevations. These maps, however, usually

are drawn to a scale that cannot be relied on for evaluating small parcels and do not eliminate the need for

field investigation of potential sewage sludge land application sites. The use of regional and soil survey maps

can help eliminate potentially unsuitable areas. Table

5-7 summarizes important criteria; see Section 5.2.1 for

related Part 503 regulatory requirements.

Soils on ridge tops and steep slopes are typically well

drained, well aerated, and usually shallow. But steep

slopes, except on very permeable soils, increase the

possibility of surface runoff of sewage sludge. Soils on

concave land and broad flat lands frequently are poorly

drained and may be waterlogged during part of the year.

Soils between these two extremes will usually have

intermediate properties with respect to drainage and

runoff. Application to steep slopes (from 30 to over 50

percent) in forested areas may be possible under specific conditions (e.g., properly buffered slopes with good

forest floor/understory vegetation, depending on the

type of soil, vegetation, and sewage sludge) if it can be

shown that the risk from runoff is low. Forest sites, which

generally have a very permeable forest floor, and new

technology for applying dewatered sewage sludge in

forests greatly reduce the potential for overland flow.1

The steepness, length, and shape of slopes influence

the rate of runoff from a site. Rapid surface water runoff

accompanied by soil erosion can erode sewage sludge

soil mixtures and transport them to surface waters.

Therefore, state regulations/guidelines often stipulate

the maximum slopes allowable for sewage sludge land

application sites under various conditions regarding

sludge physical characteristics, application techniques,

and application rates. Specific guidance should be

1

 Henry, C. 1995. Personal communication, Dr. Charles Henry, Pack

Forest Research Center, University of Washington, Eatonville, WA.

46
obtained from appropriate regulatory agencies; for general guidance, suggested limits are presented in Table

5-8.

5.5.3.2 Soils and Geology

Soil survey reports can be obtained from local SCS

offices and are suitable for preliminary planning. When

potential sites are identified, field inspections and investigations are necessary to confirm expected conditions

(Section 5.4.2). The SCS mapping units cannot represent

areas smaller than 0.8 to 1.2 ha (approximately 2 to 3

acres). Thus, there is a possibility that small areas of

soils with significantly different characteristics may be

located within a mapping unit but not identified. SCS soil

surveys provide information on typical characteristics of

soil map units that are very useful for identifying the

most favorable soils within a potential site and for comparing relative suitability of different possible sites. Section 5.9.8 (Table 5-15) illustrates how relevant information

on soil types can be compiled.

The texture of the soil and parent geologic material is

one of the most important aspects of site selection

because it influences permeability, infiltration, and drainage. It is important that a qualified soil scientist be

involved in the assessment of soils at potential land

application sites. 

With proper design and operation, sewage sludge can

be successfully applied to virtually any soil. However,

highly permeable soil (e.g., sand), highly impermeable

soil (e.g., clay; although the addition of organic material

in sewage sludge may help reduce impermeability), or

poorly drained soils may present special design requirements. Therefore, sites with such conditions should generally be given a lower priority during the preliminary site

selection process. Table 5-9 summarizes typical guidelines for soil suitability. In some cases, the favorable

aspects (i.e., location, municipal ownership, etc.) may

outweigh the costs of mitigation measures. 

Soil Permeability and Infiltration

Permeability (a property determined by soil pore space,

size, shape, and distribution) refers to the ease with

which water and air are transmitted through soil. Finetextured soils generally possess slow or very slow permeability, while the permeability of coarse-textured soils

ranges from moderately rapid to very rapid. A mediumTable 5-7. Potentially Unsuitable Areas for Sewage Sludge

Application

Areas bordered by ponds, lakes, rivers, and streams without

appropriate buffer areas.

Wetlands and marshes without a permit.

Steep areas with sharp relief.

Undesirable geology (karst, fractured bedrock) (if not covered by a

sufficiently thick soil column).

Undesirable soil conditions (rocky, shallow).

Areas of historical or archeological significance.

Other environmentally sensitive areas such as floodplains or

intermittent streams, ponds, etc., as specified in the Part 503

regulation.

Table 5-8. Recommended Slope Limitations for Land

Application of Sewage Sludge

Slope Comment

0-3% Ideal; no concern for runoff or erosion of liquid or

dewatered sludge.

3-6% Acceptable for surface application of liquid or

dewatered sludge; slight risk of erosion.

6-12% Injection of liquid sludge required in most cases,

except in closed drainage basin and/or areas with

extensive runoff control. Surface application of

dewatered sludge is usually acceptable.

12-15% No liquid sludge application without effective runoff

control; surface application of dewatered sludge is

acceptable, but immediate incorporation is

recommended.

Over 15% Slopes greater than 15% are only suitable for sites

with good permeability (e.g., forests), where the

steep slope length is short (e.g., mine sites with a

buffer zone downslope), and/or the steep slope is a

minor part of the total application area.

Table 5-6. Suggested Provisions of Contracts Between

Sewage Sludge Preparer, Sludge Applier, and

Private Landowners (Sagik et al., 1979)

Identification of the landowner, the preparer, and the applier

spreading the sludge.

Location of land where application is to occur and boundaries of

the application sites.

Entrance and exit points to application sites for use by spreading

equipment.

Specification of the range of sludge quality permitted on the land.

Parameters identified might include percent of total solids;

levels of trace elements and pathogens in the sludge, and

vector attraction reduction, as regulated by Part 503; additional

state and local parameters required. The contract would specify

who is to pay for the analysis, and frequency of analysis.

Agreement on the timing of sludge application during the cropping

season. Application rates and acceptable periods of application

should be identified for growing crops, as well as periods when

the soil is wet.

Agreements on the application rate (agronomic rate). This rate

might vary through the year depending on the crop, the sludge

analyses, and when and where application is occurring.

Restrictions on usage of land for growing root crops or fresh

vegetables, or for grazing livestock.

Conditions under which either party may escape from provisions of

the contract or be subject to indemnification or liability issues.

47
textured soil, such as a loam or silt loam, tends to have

moderate to slow permeability. 

Soil Drainage

Soils classified as (1) very poorly drained, (2) poorly

drained, or (3) somewhat poorly drained by the Soil

Conservation Service may be suitable for sewage

sludge application if runoff control is provided. Soils

classified as (1) moderately well-drained, (2) well

drained, or (3) somewhat excessively drained are generally suitable for sewage sludge application. Typically,

a well-drained soil is at least moderately permeable. 

5.5.3.3 Surface Hydrology, Including

Floodplains and Wetlands

The number, size, and nature of surface water bodies

on or near a potential sewage sludge land application

site are significant factors in site selection due to potential contamination from site runoff and/or flood events.

Areas subject to frequent flooding have severe limitations for sewage sludge application. Engineered flood

control structures can be constructed to protect a land

application site against flooding, but such structures can

be prohibitively expensive. 

5.5.3.4 Ground Water

For preliminary screening of potential sites, it is recommended that the following ground-water information for

the land application area be considered: 

• Depth to ground water (including historical highs and lows). 

• An estimate of ground water flow patterns.

When a specific site or sites has been selected for

sewage sludge application, a detailed field investigation

may be necessary to determine the above information.

During preliminary screening, however, published general

resources may be located at local USGS or state water

resource agencies.

Generally, the greater the depth to the water table, the more

desirable a site is for sewage sludge application. Sewage

sludge should not be placed where there is potential for

direct contact with the ground-water table. The actual

thickness of unconsolidated material above a permanent

water table constitutes the effective soil depth. The desired

soil depth may vary according to sludge characteristics,

soil texture, soil pH, method of sludge application, and

sludge application rate. Table 5-10 summarizes recommended criteria for the various land application practices. 

The type and condition of consolidated material above the

water table is also of major importance for sites where high

application rates of sewage sludge are desirable. Fractured rock may allow leachate to move rapidly. Unfractured

bedrock at shallow depths will restrict water movement,

with the potential for ground water mounding, subsurface

lateral flow, or poor drainage. Limestone bedrock is of

particular concern where sinkholes may exist. Sinkholes,

like fractured rock, can accelerate the movement of

leachate to ground water. Thus, potential sites with potable

ground water in areas underlain by fractured bedrock, by

Table 5-9. Soil Limitations for Sewage Sludge Application to Agricultural Land at Nitrogen Fertilizer Rates in Wisconsin (Keeney

et al., 1975)

Degree of Soil Limitation

Soil Features Affecting Use Slight Moderate Severe

Slopea Less than 6% 6 to 12% More than 12%

Depth to seasonal water table More than 1.2 m 0.6 to 1.2 m Less than 1 m

Flooding and ponding None None Occasional to frequentb

Depth to bedrock More than 1.2 m 0.6 to 1.2 m Less than 0.61 m

Permeability of the most restricting layer

above a 1-m depth

0.24 to 0.8 cm/hr 0.8 to 2.4 cm/hr

0.08 to 0.24 cm/hr

Less than 0.08 cm/hr

More than 2.4 cm/hr

Available water capacity More than 2.4 cm 1.2 to 2.4 cm Less than 1.2 cm

a

 Slope is an important factor in determining the runoff that is likely to occur. Most soils on 0 to 6% slopes will have slow to very slow runoff;

soils on 6 to 12% slopes generally have medium runoff; and soils on steeper slopes generally have rapid to very rapid runoff. b

 Land application may be difficult under extreme flooding or ponding conditions.

Metric conversions: 1 ft = 0.3048 m, 1 in = 2.54 cm.

Table 5-10. Recommended Depth to Ground Water

Type of Site Drinking Water Aquifera Excluded Aquiferb

Agricultural 1-2 m 0.5 m

Forest 2 mc 0.7 m

Reclamation 1-2 m 0.5 m

a

 States may have other depth-to-ground water requirements.

b

 Clearances are to ensure trafficability of surface, not for ground

water protection; excluded aquifers are not used as potable water

supplies. c

 Seasonal (springtime) high water and/or perched water less than 1 m

are not usually a concern.

Metric conversion: 1 m = 3.28 ft.

48
unfractured rock at shallow depths, or with limestone

sinkholes should be avoided. 

5.5.3.5 Climate

Analysis of climatological data is an important consideration for the preliminary planning phase. Rainfall, temperature, evapotranspiration, and wind may be

important climatic factors affecting land application of

sewage sludge, selection of land application practices,

site management, and costs. Table 5-11 highlights the

potential impacts of some climatic regions on the land

application of sewage sludge. 

Meteorological data are available for most major cities

from three publications of the National Oceanic and

Atmospheric Administration (NOAA): 

• The Climatic Summary of the United States. 

• The Monthly Summary of Climatic Data, which provides basic data, such as total precipitation, maximum and minimum temperatures, and relative

humidity, for each day of the month, and for every

weather station in the area. Evaporation data are also

given, where available. 

• Local Climatological Data, which provides an annual

summary and comparative data for a relatively small

number of major weather stations.

This information can be obtained by written request from

NOAA, 6010 Executive Boulevard, Rockville, Maryland

20852. Another excellent source is the National Climatic

Center in Asheville, North Carolina 28801. Weather data

may also be obtained from local airports, universities,

military installations, agricultural and forestry extension

services and experiment stations, and agencies managing large reservoirs. 

5.5.4 Site Screening

Site screening is an integral part of the Phase I site

evaluation process. Initially, development of land area,

transportation distance, topographic, soils, hydrologic

and other site screening criteria helps focus efforts on

collecting relevant information. One practical screening

technique involves the use of transparent (mylar) overlays with concentric rings drawn around the wastewater

treatment facility. The distance represented by the initial

ring will vary depending on facility location, sewage

sludge quantity, proximity of nearby communities, local

topography, and the land application practices being

considered. A small community might start with an area 20

km (12.5 miles) in diameter, while a large system may initially

screen a much larger study area. Shaded areas representing unsuitable locations are marked on the map or the

transparency. If the initial ring does not have suitable sites,

then the next ring with a larger diameter should be considered. It should be remembered that areas that are unsuitable

in their existing state can often be modified to make them

acceptable for sewage sludge application. The necessary

modifications (e.g., extensive grading, drainage structures,

flood control, etc.) may be cost-effective if the site is otherwise attractive in terms of location, low land cost, etc. 

5.5.4.1 Contact with Owners of Prospective Sites

When potential sites are identified, ownership should be

determined. Often the City Hall, County Courthouse, or

a real estate broker will have community or areawide

maps indicating the tracts of land, present owners, and

property boundaries. The County Recorder and title insurance companies are also useful sources of information on property ownership, size of tracts, and related

information. Contacting landowners prematurely without

adequate preparation may result in an initial negative

reaction which is difficult to reverse. A public information

program should be prepared (see Chapter 12), and local

political support secured. The individuals involved in

making the initial owner contacts should be knowledgeable about potential program benefits and constraints. 

Initial contacts concerning the proposed project should

be made with the prospective landowners/site managers

through personal interviews. Initial contacts via telephone

are not recommended to avoid misunderstandings regarding the benefits of a land application program.

Ideally, the Phase I site evaluation and screening process will identify two or three sites that merit a more

detailed Phase II site evaluation, discussed below.

5.6 Phase II Site Evaluation: Field

Investigation 

The Phase II site evaluation step involves field investigations of one or more sites to determine whether soil

survey and other map information used in the Phase I

Table 5-11. Potential Impacts of Climatic Regions on Land

Application of Sewage Sludge (Culp et al., 1980)

Climatic Region

Impact Warm/Arid Warm/Humid Cold/Humid

Operation Time Year-round Seasonal Seasonal

Operation Cost Lower Higher Higher

Storage

Requirement Less More More

Salt Buildup

Potential

High Low Moderate

Leaching

Potential Low High Moderate

Runoff Potential Low High High

49
site evaluation and screening process is accurate and

to obtain additional, more detailed information required for

final selection of the land application practice (Section 5.7)

and final site selection (Section 5.8). Chapter 6 covers

the following aspects of Phase II investigations:

• Preliminary field site surveys.

• Procedures for detailed site investigations.

• Special considerations for detailed site evaluations

for different land application practices: agricultural,

forest land, reclamation sites, and public contact sites.

5.7 Selection of Land Application

Practice 

When the most feasible land application practices have

been identified (e.g., application to agricultural land,

forests, reclamation sites, public contact sites, or lawns

and home gardens), preliminary estimates of site life

and costs (capital and O&M) for the individual practices

should be made (see Section 5.8.1). Potential social and

environmental impacts resulting from each practice also

should be assessed. Comparing these data should reveal the most suitable land application practice that fits

both the needs of the wastewater treatment facility and

local conditions. The facility might also consider adopting more than one land application practice (e.g., agricultural and forest land application) if the combined

practices appear to be cost-effective. The flow chart

shown in Figure 5-3 summarizes the procedure for selecting a land application practice.

A checklist of relevant design features for each land

application site is usually helpful for compiling information and provides baseline data for cost estimates (Table

5-12). Individual practices can be compared and evaluated based on both quantitative and qualitative factors:

• Estimated costs

• Reliability

• Flexibility

• Land area requirements and availability

• Land use effects

• Public acceptance

• Regulatory requirements (federal, state, and local)

A qualitative comparison of each land application practice

is based on the experience and judgment of the project

planners and designers. This is more difficult than a cost

comparison, because the level of each impact is more

ambiguous and subject to differences of opinion.

5.8 Final Site Selection

The final selection of the site(s) is often a simple decision

based on the availability of the best site(s). This is frequently

the case for small communities. If, however, the site

selection process is complex, involving many potential

sites and/or several sewage sludge use and/or disposal

practices, a weighted scoring system may be useful. 

The use of a quantitative scoring system for site selection

is demonstrated in the Process Design Manual for Surface

Disposal of Sewage Sludge and Domestic Septage (U.S.

EPA, in preparation). While the criteria for selecting site(s)

for the land application practices discussed in this manual

differ somewhat from those provided in the surface disposal design manual, the weighting and scoring system

may be useful. Table 5-13 presents another example of a

ranking system for forest sites, based on consideration of

topography, soils and geology, vegetation, water resources, climate, transportation, and forest access.

Several other considerations should be integrated into

the decision-making process, including: 

• Compatibility of sewage sludge quantity and quality

with the specific land application practice selected.

• Public acceptance of both the practice(s) and site(s)

selected.

• Anticipated design life, based on assumed application rate, land availability (capacity), projected heavy

metal loading rates (if Part 503 cumulative pollutant

loading rates are being met, as defined in Chapter

3), and soil properties.

5.8.1 Preliminary Cost Analysis 

A preliminary estimate of relative costs should be made

as part of the site selection process. These estimates

are necessary for comparing alternative sites and/or

land application practices.

Proximity of the sewage sludge land application site to

the wastewater treatment facility is very important in the

decision-making process because of transportation

costs. Further, the cost of sludge dewatering equipment

should be evaluated in view of estimated fuel savings

through decreased total loads and/or shorter haul distances. For ease of comparison, all costs can be expressed in dollars per dry weight of sewage sludge.

Capital costs should be estimated over the life of the

site, whereas operating costs should be estimated annually. Cost factors that are of prime importance are

summarized in Table 5-14. These assessments should

be based on experience and best engineering judgment.

Chapter 16 discusses cost estimations in more detail.

5.8.2 Final Site Selection

The Phase I and Phase II site evaluation process should

result in detailed information on two or more sites that

have been identified as suitable for the selected land

application practice. This information, combined with the

preliminary cost analysis (Section 5.8.1) should provide

50
Figure 5-3. Planning, site selection, and land application practice selection sequence.

51
Table 5-12. Example Design Features Checklist/Comparison of Candidate Land Application Practices

Candidate Practice or Combination of Practices

Subject Agriculture Forest Reclamation

 1. Distance and travel time from POTW to the 

 candidate site

 2. Distance and travel time from the storage 

 facility to the candidate site

 3. Distance from the nearest existing development, 

 neighbors, etc., to the candidate site

 4. Sludge modification requirements, e.g., 

 dewatering

 5. Mode of sludge transportation

 6. Land area required

 7. Site preparation/construction needs:

a. None

b. Clearing and grading

c. Access roads (on-site and off-site)

d. Buildings, e.g., equipment storage

e. Fences

f. Sludge storage and transfer facilities

g. On-site drainage control structures

h. Off-site runoff diversion structures

i. On-site runoff storage

j. Flood control structure

k. Ground water pollution control structure,

 e.g., subsurface drain system

l.Soil modification requirements,

 e.g., lime addition, etc.

 8. Equipment needs:

a. Sludge transport vehicle

b. Dredge

c. Pumps

d. Crawler tractor

e. Subsurface injection unit

f. Tillage tractor

g. Sludge application vehicle

h. Nurse tanks or trucks

i. Road sweeper

j. Washing trucks

k. Irrigation equipment

l. Appurtenant equipment

 9. Monitoring requirements:

a. Soil

b. Sludge analysis

10. Operational needs

a. Labor

b. Management

c. Energy

d. Repair

52
a basis for selecting the most cost-effective site or sites.

The next section provides an example of the site evaluation and selection process.

5.9 Site Selection Example 

Each of the process design chapters (Chapters 7

through 9) provides a detailed example of the design of

a specific land application system for agricultural, forest,

and reclamation sites. This section provides a brief example of the site selection procedure that could be used

for a typical medium-sized community. 

5.9.1 City Characteristics

• Population–34,000. 

• Wastewater volume–0.18 m3/s (4 mgd). 

• Wastewater treatment facility description–conventional activated sludge, with anaerobic digestion of

primary and waste-activated sludges.

5.9.2 Sewage Sludge and Soil Characteristics

• Daily sludge generation–2.36 dry t/day (2.6 dry T/day).

• Average solids content–4 percent.

• Average chemical properties (dry weight basis):

– Total N–3 percent

– NH4-N–1 percent 

– Total P–2 percent

– Total K–0.5 percent

• Metal regulated by Part 503 (in mg/kg):

– As–10 – Hg–7

– Cd–19 – Mo–12

– Cr–800 – Ni–150

– Cu–700 – Se–19

– Pb–500 – Zn–2,000

• Soil is maintained at pH 6.5 or above when required

for optimum crop production.

5.9.3 Regulations Considered

Assume that agricultural land application is the only

practice being considered, and that special permits are not

required for sewage sludge application, provided that:

Table 5-13. Relative Ranking for Forest Sites for Sewage

Sludge Applicationa

Factor Relative Rank

Topography

Slope

less than 10%

10-20%

20-30%

over 30%

High

Acceptable

Low

Low

Site continuity (somewhat subjective)

no draws, streams, etc., to buffer

1 or 2 requiring buffers

numerous discontinuities

High

Acceptable

Low

Transportation

Distance Low-High

Condition of the roads Low-High

Travel through sensitive areas Low-High

Forest Access System

Percent of forest system in place Low-High

Ease of new construction

easy (good soils, little slope, 

young trees)

difficult

High

Low-Acceptable

Erosion hazard

little (good soils, little slope)

great

High

Low-Acceptable

Soil and Geology

Soil type

sandy gravel (outwash, Soil Class I)

sandy (alluvial, Soil Class II)

well graded loam (ablation till, Soil Class IV)

silty (residual, Soil Class V)

clayey (lacustrine, Soil Class IV)

organic (bogs)

High

High

Acceptable

Acceptable

Low

Low

Depth of soil

deeper than 10 ft

3-10 ft

1-3 ft

less than 1 ft

High

High

Acceptable

Low

Geology (subjective, dependent upon aquifer)

sedimentary bedrock

andesitic basalt

basal tills

lacustrine

Acceptable-High

Acceptable-High

Low-Acceptable

Low

Vegetation

Tree species

Hybrid cottonwood (highest N uptake rates)

Douglas-fir

other conifers

other mixed hardwoods

red alder

High

High

High

Acceptable

Low

Table 5-14. Cost Factors To Be Considered During Site

Selection

Capital Costs

• Land acquisition—purchase, lease, or use of private land.

• Site preparation—grading, roads, fences, drainage, flood

control, and buildings (if needed).

• Equipment—sludge transport and application.

• Sludge storage facilities.

Operating Costs

• Fuel for sludge transport and application.

• Labor (transport, application, maintenance, sampling, etc.)

• Equipment repair.

• Utilities.

• Monitoring, if required (laboratory analysis, sample containers,

shipping).

• Materials and miscellaneous supplies.

53
1. Annual sewage sludge applications do not exceed either

the agronomic rate or the Part 503 limits for metals.

2. Annual program for routine soil testing (N, P, K) and

lime requirement (pH) is implemented. 

3. Wastewater treatment plant measures the chemical

composition of sludge. 

4. Records are maintained on the location and the

amount of sludge applied. 

5. The site is not 10 meters or less from waters

classified as waters of the United States.

5.9.4 Public Acceptance 

Assume that public acceptance of land application of

sewage sludge is judged to be very good. Several

nearby communities have previously established agricultural land application programs with excellent results.

Sewage sludge characteristics from these communities

were similar, as were farm management and cropping

patterns involving corn, oats, wheat, and pastureland.

Several articles had appeared in the local newspaper

indicating that escalating landfill costs were causing the city

to study various sewage sludge use and disposal alternatives. No public opposition groups are known to exist.

 5.9.5 Preliminary Feasibility Assessment

The above preliminary information was sufficiently encouraging to warrant further study of agricultural land

application.

5.9.6 Estimate Land Area Required

An application rate of 22.4 t/ha/year (10 T/ac/year) was

used as a first approximation (see Table 5-1). The acreage required for the city was estimated as follows: 

Acreage needed = 2.36 t/day × 365 days/yr

22.4 t/ha/yr = 38.4 ha

Thus, assume 40 ha (100 ac) for the preliminary search.

5.9.7 Eliminate Unsuitable Areas

Figure 5-4 shows a general area map containing the city

and surrounding communities. Three concentric rings of

10, 20, and 30 km (6.2, 12.4, and 18.6 mi) were drawn

around the wastewater treatment facility. Areas directly

south of the facility were immediately excluded because

of the city boundaries. Similarly, areas east and southeast were excluded because of the city’s projected

growth pattern, the encroachment of a neighboring city,

and the municipal airport. Further investigations to identify potential land application sites were thus concentrated to the west and northwest. 

Figure 5-4. General area map with concentric rings.

Figure 5-5. General soil map showing area selected for sewage

sludge land application.

54
5.9.8 Identify Suitable Areas

Soil maps obtained from the local SCS office were examined within the three radii selected. Areas within the 10-km

(7-mi) ring were given first priority because of their proximity to the wastewater treatment facility. Sufficient land

was located within this distance, and the areas contained

within the second and third radii were not investigated.

Figure 5-5 is a general soil map showing one potential

area available for sewage sludge land application. A

detailed soil map of the area is shown in Figure 5-6, and

the map legend is presented in Table 5-15.

Information presented in the soil survey report included:

slope, drainage, depth to seasonal water table, and depth to

bedrock. Cation exchange capacities (CEC) were estimated

Table 5-15. Ranking of Soil Types for Sewage Sludge Application

Depth to

Soil Type

Slope

Percent

Seasonal High

Water Table (ft)

Bedrock

(ft) Texture*

Drainage

Class† Approximate

CEC

Relative

Ranking#

AvA** 0-2 1-3 >15 sil P 10-15 3

Ca** 0.2 >6 >15 sil W 10-15 1

CnB2** 2-6 >6 >15 sil W 10-15 1

CnC2 6-12 >6 >15 sil W 10-15 2

CnC3 6-12 >6 >15 sil W 10-15 2

Cn02 12-18 >6 >15 sil W 10-15 3

Cn03 12-18 >6 >15 sil W 10-15 3

Fe** 0-2 3-6 >15 sil W 10-15 2

FoA** 0-2 >6 >15 l W 10-15 1

FoB2 2-4 >6 >15 l W 10-15 1

FoC3 6-12 >6 >15 l W 10-15 2

Ge 0-2 >6 >15 l W 10-15 1

Hh 0-2 1-3 >10 sil SP 10-15 3

La 0-2 >6 >15 gsal W >5 1

MbA 0-2 >6 >15 l W 10-15 1

MbB2 2-6 >6 >15 l W 10-15 1

Md 0-2 3-6 >15 sicl MW >15 2

NgA** 0-2 >6 >15 l W 10-15 1

NgB2** 2-6 >6 >15 l W 10-15 1

NnA 0-2 >6 >15 l W 10-15 1

RnF 0-2 >6 >15 gl E >5 1

Ro** 0-2 >6 >15 sicl W >15 1

Rp 0-2 >6 >15 sicl W >15 1

RsB2 2-6 3-6 >15 sil MW 10-15 2

Sc 0-2 0-1 >15 sicl VP >15 3

Sh** 0-2 1-3 >15 sil SP 10-15 3

Sm 0-2 1-3 >15 l SP 10-15 3

Sz 0-2 >6 >15 sal W 5-10 1

Wc** 0-2 0-1 >15 cl VP >15 3

Wh** 0-2 1-3 >15 l SP 10-15 3

* l, loam; gsal, gravelly sandy loam; sil, silt, loam; sicl, silty clay loam; cl, clay loam; sal, sandy loam; gl, gravelly loam.

†

 E, excessively drained; W, well drained; MW, moderately well drained, SP, somewhat poorly drained; P, poorly drained; VP, very poorly drained.

#

 1, 0-6 percent slope, >6 ft to water table and >15 to bedrock. 2, 6-12 percent slope or 3-6 ft to water table. 3, 12-18 percent slope or 0-3 ft to water table.

** Soil types present on potential site (see Figure 5-6). Soil type information from SCS county soil survey.

55
from texture, and a ranking was developed to estimate

soil suitability for sewage sludge application.

Since the detailed soil map was based on an aerial

photo, farm buildings, houses, etc., were usually identifiable. Certain portions within this area were excluded,

including: 

• Areas in close proximity to houses, schools, and

other inhabited buildings. 

• Areas immediately adjacent to ponds, lakes, rivers,

and streams. 

The excluded areas were shaded (Figure 5-6), using a

mylar overlay. The remaining unshaded areas, covering

about 930 ha (2,300 ac), were generally pastureland with

some fields of corn and oats. Within this area was about

175 ha (432 ac) which ranked in Category 1 in Table 5-15.

The land in the site area was owned by three individuals.

Since the 175 ha (432 ac) was far in excess of the 40 ha

(100 ac) required, no further sites were investigated. Soils

present in the area were generally silt loams. Representative soil analysis was as follows:

• CEC - 10 meq/100 g. 

• Soil pH - 6.0 (1:1 with water). 

• Available P - 16.8 kg/ha (15 lb/ac). 

• Available K - 84 kg/ha (75 lb/ac). 

• Lime necessary to raise pH to 6.5 - 5.4 t/ha (2.4 T/ac).

The three landowners were contacted individually to

determine their willingness to participate. All expressed

considerable interest in participating in the program. 

5.9.9 Phase II Site Survey and Field

Investigation

These efforts confirmed the suitability of the site selected. Agreements were thus made with each landowner to land apply municipal sewage sludge. 

5.9.10 Cost Analysis

No land costs were incurred since the landowners

agreed to accept the sewage sludge. Capital costs included: transportation vehicle, application vehicle,

sludge-loading apparatus with pumps, pipes, concrete

pad, electrical controls, and storage facilities. Annual

costs for this system were estimated to be $110/dry t

($98/dry T), as compared to $128/dry t ($116/dry T) for

landfilling the sludge at a site 25 km (15.5 m) from the

wastewater treatment facility. 

5.9.11 Final Site Selection

The 175 ha (432 ac) of best quality land were distributed over seven individual fields, several of which

were not serviced by all-weather roads. These fields

would only be used if complicating factors (e.g., field

or crop conditions) rendered the other fields unusable.

The contractual agreement with the three individuals

specified that sewage sludge would be land applied

to certain fields (to be determined at owner discretion)

at rates commensurate with crop nitrogen requirements and in compliance with the Part 503 pollutant

limits for metals and other Part 503, state, and local

regulatory requirements.

5.10 References

When an NTIS number is cited in a reference, that 

document is available from: 

 National Technical Information Service

 5285 Port Royal Road

 Springfield, VA 22161

 703-487-4650

Culp, G., J. Faisst, D. Hinricks, and B. Winsor. 1980. Evaluation of

sludge management systems: Evaluation checklist and supporting

commentary. EPA/430/9-80/001 (PB81108805). Cul/Wesner/Culp,

El Dorado Hills, CA.

Deese, P., J. Miyares, and S. Fogel. 1980. Institutional constraints

and public acceptance barriers to utilization of municipal wastewater and sludge for land reclamation and biomass production: A

report to the president’s council on environmental quality. (EPA

430/9-81-013; July 1981).

Keeney, D., K. Lee, and L. Walsh. 1975. Guidelines for the application

of wastewater sludge to agricultural land in wisconsin. Technical

Bulletin 88, Wisconsin Department of Natural Resources, Madison, WI.

Sagik, B., B. Moore, and C. Forber. 1979. Public health aspects

related to the land application of municipal sewage effluents and

sludges. In: Sopper, W.E., and S.M. Kerr, eds. Utilization of municipal

sewage effluent and sludge on forest and disturbed land. Pennsylvania State University Press, University Park, PA. pp. 241-263.

U.S. EPA. 1995. Process design manual: Surface disposal of sewage

sludge and domestic septage. EPA/625/R-95/002. Cincinnati, OH.

U.S. EPA. 1984. Environmental regulations and technology: Use and

disposal of municipal wastewater sludge. EPA/625/10-84-003.

Washington, DC.

Figure 5-6. Detailed soil survey map of potential site for sewage sludge land application. (Areas not suitable for

use are shaded; see Table 5-17 for ranking of soil

types.)

56
Chapter 6

Phase II Site Evaluation

6.1 General

The Phase I site evaluation and screening process described in Chapter 5 will usually identify a number of

candidate sites for land application of sewage sludge

that require more detailed investigation before final site

selection. The extent and type of information gathered

in field investigations for a Phase II site evaluation will

vary depending on:

• Land application practice being considered, e.g., agricultural, forest, or land reclamation.

• Regulatory requirements.

• Completeness and suitability of information on soils,

topography, and hydrogeology obtained from other

sources (e.g., the SCS, USGS, etc).

General site characteristics can be obtained from a

combination of soil survey maps and site visits. The

principal soil chemical analyses required are soil tests

which are routinely conducted to develop recommendations for application of conventional fertilizer materials.

Table 6-1 provides a summary of the site-specific information required for different land application practices.

This information is of a general nature and can usually

be obtained from site visits without field sampling and

testing. Review of this information may eliminate some

potential sites from further consideration.

6.2 Preliminary Field Site Survey

A field site survey should be conducted after potential

sites have been identified in the map study performed

during the Phase I site evaluation. A drive or walk

through the candidate areas should verify or provide

additional information on:

• Topography. Estimate of slope both on prospective

site and adjacent plots.

• Drainage. Open or closed drainage patterns.

• Distance to surface water.

• Distance to water supply well(s).

• Available access roads. All-weather or temporary.

• Existing vegetation/cropping.

A field survey form similar to the one shown in Table 6-2

that records the current condition of all critical factors is

recommended. The data collected from various sites

can then be used to update the map overlay (see Chapter 5). The appropriate additional information for different land uses in Table 6-1 (agricultural crops, forest land,

reclamation sites) should also be gathered.

Table 6-1. Basic Site-Specific Information Needed for Land

Application of Sewage Sludge

Property Ownership

Physical Dimensions of Site

a. Overall boundaries

b. Portion usable for sludge land application under constraints

of topography, buffer zones, etc.

Current Land Use

Planned Future Land Use

If Agricultural Crops Are To Be Grown:

a. Cropping patterns

b. Typical yields

c. Methods and quantity of fertilizer application

d. Methods of soil tillage

e. Irrigation practices, if any

f. Final use of crop grown (animal/human consumption,

non-food chain, etc.)

g. Vehicular access within site

If Forest Land:

a. Age of trees

b. Species of trees

c. Commercial or recreational operation

d. Current fertilizer application

e. Irrigation practices

f. Vehicular access within site

If Reclamation Site:

a. Existing vegetation

b. Historical causes of disturbance (e.g., strip mining of coal,

dumping of mine tailings, etc.)

c. Previous attempts at reclamation, if any

d. Need for terrain modification

Surface/Ground Water Conditions

a. Location and depth of wells, if any

b. Location of surface water (occasional and permanent)

c. History of flooding and drainage problems

d. Seasonal fluctuation of ground water level

e. Quality and users of ground water

57
6.3 Site-Specific Field Investigations

This section focuses on basic field investigation methods applicable to agricultural and forest land application

sites, which typically encompass areas of tens to hundreds of hectares, but for which detailed maps (1:6,000

or less) generally are not available. In general, active

reclamation sites often have detailed maps and extensive environmental data that have been prepared and

collected as part of the permitting process, so specific

additional information for determining sewage sludge

application rates may not be required. Section 6.5 discusses special considerations related to investigation of

reclamation sites involving abandoned land.

Where land application of bulk sewage sludge is being

considered for public contact sites, such as parks, detailed site maps may be available that can be used for

the type of investigations described here. Otherwise,

field investigation procedures described in this section

are applicable. Application of bagged sewage sludge on

public contact sites, lawns, and home gardens will not

require site-specific field investigations.

6.3.1 Base Map Preparation

Major types of commonly available maps that contain

useful information for site field investigations include

(1) U.S. Geological Survey (USGS) 7.5 minute topographic maps (scale 1:24,000), (2) published Soil Conservation Service (SCS) soil survey maps (which usually

range in scale from 1:15,000 to 1:20,000), (3) Federal

Emergency Management Agency (FEMA) floodplain

maps, and (4) U.S. Fish and Wildlife Service National

Wetland Inventory Maps.

Site boundaries from a recent survey or County records

should be located as accurately as possible on all maps

that have been collected for the site. The accuracy of

points on a USGS 7.5 minute quadrangle map (about

plus or minus 50 feet) is generally not sufficient for

detailed site evaluation for sewage sludge land application, but the expense of preparing a larger scale topographic base map will usually not be justified. Enlarging

the area of a topographic map that includes the site of

interest using a copy machine is the simplest way to

obtain a larger scale working map for field investigations. The same can be done for a soil map of the area,

if available. The original scale bars of the map should

be included or enlarged separately so that the actual

scale of the enlarged map can be determined. Information from other maps, such as flood plain boundaries,

should also be transferred to the working base map.

Another way to obtain a larger scale topographic base

map, if the computer equipment and software are available, is to obtain the appropriate USGS map in digital

format, which then can be used to print a base map of

the desired area and scale.

6.3.2 Field Checking of Surface Features and

Marking Buffer Zones on the Base Map

Key point and linear surface features on the base map

that should be added or checked in the field include:

(1) location of surface water features (springs, intermittent and perennial surface streams, ponds and

streams); (2) location of ground water wells, and (3)

location of residences, other buildings, public roads,

fencelines and other man-made features. Accuracy of

surface features on the enlarged base map can be

checked by first measuring distances between points on

the map that can be easily located in the field, and then

measuring the actual distance. For example, measuring

the distance of a site corner by a roadway from the point

that a stream crosses the site boundary at the road is

relatively easy to measure in the field by pacing or using

a 100-ft tape measure. Any major features that are not

within about 10 feet of the marked location on the enlarged topographic base map should be redrawn. Also,

Table 6-2. Sample Form for Preliminary Field Site Survey

A. PROPERTY LOCATION PROPERTY OWNER

B. TOPOGRAPHY

1. Relief (sharp, flat, etc.)____________________________

2. Slope Estimate __________________________________

3. Drainage Patterns

 - Open/Closed __________________________________

 - Drainage Class No.* ____________________________

 - Any Underdrains _______________________________

C. DISTANCE FROM SITE BOUNDARY TO:

1. Surface Water __________________________________

2. Water Supply Well _______________________________

D. ESTIMATE OF SITE DIMENSIONS

1. Area __________________________________________

2. Natural Boundaries ______________________________

3. Fences ________________________________________

E. AVAILABLE ACCESS

1. Road Types ____________________________________

2. Other _________________________________________

F. EXISTING VEGETATION/CROPS AND COMMONLY USED

CROP ROTATIONS

1. On-Site ________________________________________

2. Neighboring Properties____________________________

G. SOIL

1. Texture ________________________________________

2. Variability ______________________________________

*Refer to Soil Conservation Service drainage classes.

58
any significant surface features that are not on the base

map should be added.

The field-checked and revised base map allows reasonably accurate delineation of any buffer zones where

sewage sludge should not be applied. The Part 503 rule

specifies a minimum buffer of 10 meters from surface

waters at a land application site unless otherwise specified by the permitting authority. Many states specify

larger buffers to surface waters and may specify buffers

to wells, dwellings, property lines, and other features.

Any applicable setback distances should be marked on

the field-checked base map.

6.3.3 Identifying Topographic Limitations

Many state regulatory programs define slope grade limits for land application of sewage sludge that may vary

according to the type of land use (e.g., agricultural,

forest, or reclamation site) and method of application

(Table 5-8). The appropriate regulatory authority should

be contacted to identify any slope limitations that might

apply to the site. An SCS soil survey (see Section 6.3.4)

is the easiest way to identify areas with similar slope

ranges because soil map units are usually differentiated

according to slope classes. Soil map units with slopes

that exceed the applicable limitations should be marked

as potentially unsuitable areas before going into the

field. Depending on the type of soil or application

method (e.g., surface application, incorporation, or injection), different slopes may be appropriate. Areas with

differing slope limits should be identified on the same

map; alternatively, separate maps may be developed

that identify potentially unsuitable areas because of differing slope limitations.

The above map(s) needs to be taken into the field to

check the accuracy of the boundaries separating suitable and unsuitable areas based on slope. In most

situations, spot checking of actual slope gradients using

a clinometer and a surveyor’s rod will be adequate

(Boulding, 1994 and U.S. EPA, 1991 describe this procedure in more detail). Such field checking is likely to

result in slight to moderate adjustments to the boundaries delineating areas with unsuitable slopes. The fieldchecked topographic boundaries should be marked on the

enlarged topographic base map described in Section 6.3.1.

6.3.4 Field Soil Survey

If available, a county soil survey published by the SCS

is the best single source of information about a site

because it also provides an indication of subsurface

geologic and hydrogeologic conditions and contains a

wealth of information on typical soil physical and chemical characteristics. If a soil survey is not available, check

to see if the current or previous property owners have

worked with the local Soil and Water Conservation District. If so, an unpublished farm survey may be on file in

the District SCS office. If an unpublished soil survey is

available, SCS soil series descriptions and interpretation

sheets should be obtained for all soil series that have

been mapped in the area (see Table 6-3). Estimated soil

properties are typically given as ranges or values for

different soil horizons; direct field observation and sampling are required for more accurate definition of soil

properties. Even if a published soil survey is available,

Table 6-3. Types of Data Available on SCS Soil Series

Description and Interpretation Sheets

Soil Series Description Sheet

Taxonomic Class

Typical soil profile description

Range of characteristics

Competing series

Geographic setting

Geographically associated soils

Drainage and permeability

Use and vegetation

Distribution and extent

Location and year series was established

Remarks

Availability of additional data

Soil Survey Interpretation Sheet*

Estimated Soil Properties (major horizons)

Texture class (USDA, Unified, and AASHTO)

Particle size distribution

Liquid limit

Plasticity index

Moist bulk density (g/cm3)

Permeability (in/hr)

Available water capacity (in/in)

Soil reaction (pH)

Salinity (mmhos/cm)

Sodium absorbtion ratio

Cation exchange capacity (Me/100g)

Calcium carbonate (%)

Gypsum (%)

Organic matter (%)

Shrink-swell potential

Corrosivity (steel and concrete)

Erosion factors (K, T)

Wind erodability group

Flooding (frequency, duration, months)

High water table (depth, kind, months)

Cemented pan (depth, hardness)

Bedrock (depth, hardness)

Subsidence (initial, total)

Hydrologic group

Potential frost action

Use/Suitability Ratings

Sanitary facilities

Source material

Community development

Water management

Recreation

Crop/pasture capability and predicted yields

Woodland suitability

Windbreaks (recommended species for planting)

Wildlife habitat suitability

Potential native plant community (rangeland or forest)

* Units indicated are those used by SCS.

 Note: Italicized entries are particularly useful for evaluating contaminant transport.

59
these sheets provide a convenient reference for characteristics of soil series occurring within a site. The same

information on individual soil series can be found in the

text portion of an SCS soil survey, but is scattered

through different sections and tables in the report.

Although published soil surveys provide much useful

information for preliminary site selection, they may not

be adequate for site-specific evaluation for land application of sewage sludge. For example, areas of similar

soils that cover less than 4 or 5 acres are generally not

shown on published SCS county soil surveys. For sitespecific evaluation and design purposes, it is desirable

to identify areas of similar soil characteristics that are as

small as an acre. The SCS may be able to prepare a

more detailed soil survey of a site that has been selected

for land application of sewage sludge. If SCS has a large

backlog of requests, however, obtaining a more detailed

soil survey can take months. A detailed soil survey

prepared by consulting soil scientists will be more expensive, but will usually involve less delay. If a private

consultant conducts the soil survey, the person or persons actually carrying out the survey should be trained

in soil mapping and classification methods used by SCS

for the National Cooperative Soil Survey.

Field checking of soil map unit boundaries and delineation of smaller units omitted from an existing SCS soil

survey can be done using an enlarged soil map, as

described for the topographic base map in Section 6.3.1.

Alternatively, revised soil map unit delineations or new

mapping can be done directly on the working topographic base map. An added benefit of more detailed

soil mapping at a site is that it will also provide additional

site-specific information for delineation of floodplains

and wetlands (Section 6.3.5), and for hydrogeologic

interpretations where ground-water is relatively shallow

(Section 6.3.6). The soil survey will also be helpful in

planning soil sampling for designing agronomic rates of

sewage sludge application (Section 6.4).

6.3.5 Delineation of Floodplains and

Wetlands

Some state regulatory programs place restrictions or

limitations on land application of sewage sludge on or

near floodplains and wetlands. State floodplain restrictions vary, ranging from prohibition of application on the

10-year or 100-year floodplain, to conditions on placement within a floodplain (e.g., incorporation within 48

hours, use of diversion dikes or other protective measures). Floodplains can be easily identified as low-lying

areas adjacent to streams on topographic maps and as

alluvial soils adjacent to streams on soil maps. FEMA

maps should be consulted to determine whether a site

includes a 100-year floodplain. Accurate delineation of

floodplain boundaries requires detailed engineering and

hydrologic studies. The appropriate regulatory agency

should be consulted to determine whether such detailed

investigations are required, and, if so, to identify recommended procedures.

Wetlands include swamps, marshes, bogs, and any areas that are inundated or saturated by ground water or

surface water at a frequency and duration to support a

dominant vegetation adapted to saturated soil conditions. As with floodplains, an SCS soil survey will indicate whether “hydric” soils are present at a site (e.g.,

soils that are wet long enough to periodically produce

anaerobic conditions). If wetlands are present at a site,

the appropriate regulatory agency should be contacted

to determine whether their boundaries should be accurately delineated.

Accurate wetland delineation typically requires assessment by a qualified and experienced expert in soil science and botany/biology to identify: (1) the limits of the

wetland boundary based on hydrology, soil types, and

plants types; (2) the type and relative abundance of

vegetation, including trees; and (3) rare, endangered, or

otherwise protected species and their habitats, if present. Many methods have been developed for assessing wetlands. The main guidance manuals for wetland

delineation for regulatory purposes are the Corps of

Engineers Wetlands Delineation Manual (U.S. Army

Corps of Engineers, 1987) and the Federal Manual for

Identifying and Delineating Jurisdictional Wetlands

(Federal Interagency Committee for Wetland Delineation, 1989). The latter manual places greater emphasis

on assessment of the functional value of wetlands,

along the lines of earlier work by the U.S. Fish and

Wildlife Service (U.S. Fish and Wildlife Service, 1984).

6.3.6 Site Hydrogeology

The Part 503 rule does not explicitly require investigations to characterize ground-water hydrology at sewage

sludge land application sites but does require that sewage sludge be land applied at the agronomic rate for N

for the crop or vegetation being grown. As discussed in

Section 6.4.1 on agronomic rates, some knowledge of

depth to ground water is useful when selecting appropriate sites. Tables 5-9 and 5-10 contain general guidelines for depth to ground water at land application sites.

Most states have established their own requirements for

minimum depths to ground water for sewage sludge

land application sites, which range from 1 ft to 6 ft. Also,

a number of states restrict application on highly permeable and/or very slowly permeable soils.

The field soil survey described in Section 6.3.4 will

provide the necessary information on depth to ground

water for most sites. The published soil survey report or

soil series interpretation sheet will indicate typical

depths to seasonal high water table and also expected

ranges of permeability for each major soil horizon. If

significant areas of the site have relatively shallow water

60
tables (<3 feet), it may be desirable to prepare a more

detailed depth-to-water-table map based on soil morphology, as described below. Soils with very high or very

slow permeability, as indicated by the soil survey, should

be eliminated as areas for land application of sewage

sludge, if possible. If elimination of such areas places

too great a restriction on suitable areas for land application, it may be necessary to conduct field infiltration and

permeability tests to determine whether areas of these

soils may be suitable.

6.4 Soil Sampling and Analysis to

Determine Agronomic Rates

6.4.1 Part 503 Definition of Agronomic Rate

Designing the agronomic rate for land application of

sewage sludge is one of the key elements in the Part

503 rule for ensuring that land application does not

degrade ground water quality through nitrate contamination. The Part 503 rule defines agronomic rate as:

the whole sludge application rate (dry weight

basis) designed: (1) to provide the amount of

nitrogen needed by the food crop, feed crop, fiber

crop, cover crop, or vegetation grown on the land

and (2) to minimize the amount of nitrogen in the

sewage sludge that passes below the root zone of

the crop or vegetation grown on the land to the

ground water. (40 CFR 503.11(b))

Designing the agronomic rate for a particular area requires knowledge of (1) soil fertility, especially available

N and P; and (2) characteristics of the sewage sludge,

especially amount and forms of N (organic N, NH4, and

NO3). The complex interactions between these factors

and climatic variability (which affects soil-moisture related N transformations) make precise prediction of crop

N requirements difficult.

Nitrogen fertilizer recommendations have historically

been based primarily on experience from replicated

field trials of crop response on different soil types and

management practices. Nitrogen fertilizer recommendations based on such studies often vary regionally.

The high organic N content of sewage sludge, which

becomes available for plant uptake over a period of

years as it is gradually mineralized, requires an

approximate mass balance that accounts for N needs

of the crop, availability of N in the sewage sludge and the

soil, and losses (such as volatilization and denitrification).

Chapter 7 and Chapter 8 address in detail mass balance

methods for designing agronomic rates at agricultural

and forest sites.

6.4.2 Soil Sampling

Soil sampling and analysis will usually not be needed at

land application sites until the site has been selected

and it is time to calculate sewage sludge application

rates. Soil sample collection procedures are described

in Chapter 13. The types of analyses performed on soil

samples will vary somewhat depending on the crop and

state regulatory requirements. Major constituents that

may need to be tested include:

• NO3-N as an indicator of plant-available N in the soil.

NO3 root zone profiles are widely used in states west

of the Missouri River where precipitation and leaching

are relatively low (Keeney, 1982). The pre-sidedress

nitrate test (PSNT), where soil NO3-N is sampled to

a depth of 0.3 to 0.6 m prior to corn planting or in

early June, has been found to be a good indicator of

plant-available N in humid areas (Magdoff et al.,

1984; Sander et al., 1994). Where applicable, these

tests should be made for calculating initial sewage

sludge application rates, and can possibly be used

in subsequent years as a more accurate alternative

to the equations in Chapters 7 and 8 for estimating

N mineralization rates. Chapter 13 discusses these

tests in more detail.

• C:N ratio, which provides an indication of the potential for immobilization of N in sewage sludge as a

result of decomposition of plant residues in the soil

and at the soil surface. This is especially relevant for

forest land application sites, as discussed in Chapter 8.

• Plant-available P. Where sewage sludge is applied at

rates to supply plant N needs, this test is less critical.

This test is essential, however, if sewage sludge application rates are to be based on plant P requirements (see Chapter 7).

• Plant-available K. This is required to determine supplemental K fertilization needs for optimum plant growth.

• Soil pH and pH (e.g., lime) adjustments. A soil pH of

approximately 6.5 maximizes the availability of soil

nutrients to plants and immobilization of trace metals.

Where soil pH is lower than 6.5, lime or other alkali

amendments are often added to the soil to bring pH

to the desired level.

6.5 Special Considerations for

Reclamation Sites

At reclamation sites involving abandoned mined land,

field investigations to characterize ground-water distribution and quality are usually required. The detailed site

investigation should determine the following:

• Depth to ground water, including seasonal variations

• Quality of existing ground water

• Present and potential future use of ground water

• Existence of perched water

• Direction of ground water flow

61
6.5.1 Sampling and Analysis of Disturbed Soils

Sampling and analysis of soils at reclamation sites are

necessary to:

• Establish sewage sludge application rates (typically

for a single or several [e.g., three] application(s) at

reclamation sites).

• Determine amounts of supplemental fertilizer, lime,

or other soil amendment required to obtain desired

vegetative growth.

• Determine the infiltration and permeability characteristics of the soil.

• Determine background soil pH, metals, nutrients,

etc., prior to sewage sludge application.

Soil survey maps will usually provide only an idea of the

type of soil present prior to the disturbance. Often, the

only soil profile present on a surface-mined site is the

mixture of soil and geologic materials, and the physical

and chemical characteristics of the mixture can vary

greatly over relatively short distances. A field inspection

will need to be made to determine the number and

location of samples necessary to characterize the materials. The specific analyses needed may vary from

location to location based on state and local regulations

covering both the reclamation and sewage sludge land

application aspects. Chapter 13 describes disturbed soil

sampling procedures further.

Nitrogen and phosphorus are generally deficient on

disturbed lands, and phosphorus is often the most

limiting fertility factor in plant establishment on drastically disturbed land (Berg, 1978). Soil tests used for

P analysis reflect the chemistry of soils, and thus are

more regionalized than tests for other major nutrients.

A number of soil tests have been developed for use

on acid soils in the eastern United States and on

neutral and calcareous soils in the west. Drastically

disturbed lands, however, do not always reflect the local

soils. Thus, if disturbed spoil material is going to be

analyzed for P, the local routine analysis procedure may

not be appropriate, and other P analyses might be required. Recommendations should be obtained from the

local agricultural experiment station. Testing for pH requires sufficient sampling of surface soils to characterize variations in pH; coring may be required to identify

any subsurface distribution of toxic or acid-forming spoil

material.

6.6 References

Berg, W.A. 1978. Limitations in the use of soil tests on drastically

disturbed lands. In: F.W. Schaller and P. Sutton, eds. Reclamation

of drastically disturbed lands, American Society of Agronomy,

Madison, WI. pp. 563-664.

Boulding, J.R. 1994. Description and sampling of contaminated soils:

A field guide, 2nd ed. Chelsea, MI: Lewis Publishers.

Federal Interagency Committee for Wetland Delineation. 1989. Federal manual for identifying and delineating jurisdictional wetlands.

Cooperative Technical Publication, U.S. Army Corps of Engineers,

U.S. Environmental Protection Agency, U.S. Fish and Wildlife

Service, and U.S. Department of Agriculture Soil Conservation

Service, Washington, DC.

Keeney, D.R. 1982. Nitrogen-availability indices. In: A.L. Page, ed.

Methods of soil analysis, part 2, 2nd ed. American Society of

Agronomy, Madison, WI. pp. 711-733.

Magdoff, F.R., D. Ross, and J. Amadon. 1984. A soil test for nitrogen

availability to corn. Soil Sci. Soc. Am. J. 48:1301-1304.

Sander, D.H., D.T. Walthers, and K.D. Frank. 1994. Nitrogen testing for

optimum management. J. Soil and Water Conserv. 49(2):46-52.

U.S. Army Corps of Engineers. 1987. Wetlands delineation manual. Technical Report Y-87-1. Waterways Experiment Station, Vicksburg, MI.

U.S. EPA. 1991. Description and sampling of contaminated soils: A

field pocket guide. EPA/625/2-91/002. Cincinnati, OH.

U.S. Fish and Wildlife Service. 1984. An overview of major wetland

functions and values. FWS/OBS-84/18. Washington, DC.

62
Chapter 7

Process Design for Agricultural Land Application Sites

7.1 General 

Agricultural land is the type of land most widely used for

the application of sewage sludge. This chapter presents

detailed design information for the application of sewage

sludge to agricultural land, placing primary emphasis on

the growing of crops such as corn, soybeans, small

grains, cotton, sorghum, and forages. The design example presented at the end of this chapter assumes that

the designer has (1) selected agricultural land application; (2) completed preliminary planning (see Chapter

5); and (3) chosen a transportation system to convey

sewage sludge to the application site (see Chapter 14).

The design approach presented in this chapter is based

on the use of sewage sludge as a low-nutrient fertilizing

material that can partially replace commercial fertilizers.

The goal of this approach is to optimize crop yields

through applications of both sewage sludge and supplemental fertilizers, if needed. The sewage sludge application rate is typically designed for either the nitrogen

(N) or phosphorus (P) needs of the crop grown on a

particular soil. In addition, the sewage sludge application rate must be consistent with federal, state, and local

regulations relative to pathogens, metals, and organics

contained in the sewage sludge and related requirements for vector attraction reduction.

The design example presented at the end of this chapter

also assumes that basic sewage sludge and crop production information has been collected. The sewage sludge

composition data needed to meet regulatory requirements

and ensure good design are described in Chapter 4.

Other concerns regarding agricultural land application include the possibility of odors or potential exposure to

pathogens due to inadequate sewage sludge treatment or

poor site management. The design approach described in

this chapter assumes that the sludge has been properly

stabilized to meet pathogen and vector attraction reduction

requirements and reduce odor potential.

Community acceptance of a land application project will

be more readily forthcoming if local participation is assured.

The initial task for obtaining public support begins with

the selection of a project team whose members can offer

technical service and expertise (see Chapter 12).

Information must also be available on the types of crops

to be grown, attainable yield level, and the relationship

between soil fertility tests and recommended fertilizer application rates. The overall goal is to develop a nutrient

management plan for the use of sewage sludge and fertilizer to meet the nutrient needs of the crop to be grown.

7.2 Regulatory Requirements and 

Other Considerations

Chapter 3 presents the requirements specified by the

federal Part 503 regulation. When designing a land

application system, check with state and local agencies

to learn about any other requirements that must be met.

Information on other key design considerations, such as

nutrients, pH, and land application of sewage sludge on

arid lands, is discussed below.

7.2.1 Nitrogen and Other Nutrients

7.2.1.1 Nitrogen

Nitrogen is the nutrient required in the largest amounts by

all crops. The addition of N to soils in excess of crop needs

results in the potential for NO3-N contamination of ground

water because NO3-N is not readily adsorbed by soil

particles and will move downward as water percolates

through the soil profile. Whether excess N is applied by

sewage sludge or from excessive applications of animal

manures or conventional N fertilizer materials, an increased risk of NO3-N loss to ground water may occur,

depending on climate or crop production practices. High

NO3-N levels in water supplies may result in health problems for both infants and livestock (Reed et al., 1994). The

maximum allowable concentration of NO3-N in drinking

water has been established at 10 mg/L NO3-N.

To prevent ground-water contamination by NO3-N, the

Part 503 rule requires that bulk sewage sludge be applied to a site at a rate that is equal to or less than the

agronomic rate for N at the site. This is the rate that is

designed to provide the amount of N needed by the crop

while minimizing the amount of N in the sewage sludge

63
that will pass below the root zone of the crop to the

ground water. The factors that must be considered in

deriving the agronomic application rate for a crop site

include, but are not limited to:

• The amount of N needed by the crop or vegetation

grown on the land.

• The amount of plant-available N remaining from previous applications of N-containing materials (e.g., fertilizers, irrigation water, animal manure, sewage sludge).

• The amount of organic N that is mineralized and

becomes available each year from previous applications of N-containing materials (e.g., sewage sludge,

animal manure).

• The amount of N left from biological N fixation by

leguminous crops that is mineralized and becomes

available for crops to use (i.e., legume credit).

• The type of soil at the site and the amount of N

mineralized from soil organic matter.

• Denitrification losses of NO3-N and/or volatilization

losses of ammonia.

• Any other identifiable sources or losses of N.

The design example in Section 7.5 illustrates the process

for calculating the agronomic rate.

7.2.1.2 Phosphorus

For most sewage sludge, applying sufficient sludge to

meet all the crop’s N needs will supply more P than

needed (Jacobs et al., 1993). Phosphorus does not

usually present a ground-water pollution concern. Some

states limit sludge application to cropland based on P

loading to protect surface water quality. Section 7.4.4.2 and

7.5.3 discuss sewage sludge application rates limited by P.

7.2.1.3 Other Nutrients

Sewage sludge application can be a source of micronutrients that are important for plant growth, such as iron

(Fe), manganese (Mn), and zinc (Zn). But because sewage sludge does not contain balanced amounts of nutrients, an understanding of agronomy and crop production

practices is important to prevent possible disruption of soil

fertility and plant nutrition when sludge is applied to crops

(Jacobs et al., 1993). For example, at an agricultural site

in Virginia, addition of lime-treated sludge raised the soil

pH to 7.5, resulting in manganese deficiency in soybeans.

The problem was corrected by application of Mn to foliage,

and the POTW eliminated lime conditioning to prevent excessive elevation of soil pH caused by sewage sludge

applications (Jacobs et al., 1993).

7.2.2 Soil pH and Requirements for pH

Adjustment

Some states require that soils treated with sludge be

maintained at a pH of 6.5 or above to minimize the

uptake of metals by crops based on previous EPA guidance. The federal Part 503 regulation does not require

a minimum pH of soil because pH was factored into the

risk assessment on which the regulation was based

(U.S. EPA, 1992). In addition, at least one review of the

literature on how soil pH influences the uptake of metals

suggests that the recommendation of pH 6.5 should be

reconsidered for food-chain agricultural soils, based on

reports that indicate adequate control of metals uptake

at pH 6.0 (Sommers et al., 1987). As discussed above

(Section 7.2.1.3), proper management of soil pH also is

important for good nutrient availability and crop growth.

Soil pH control has been practiced routinely in those

areas of the United States where leguminous crops

(e.g., clover, alfalfa, peas, beans) are grown. Fortunately, limestone deposits are normally abundant in

these regions, resulting in minimal costs associated with

liming soils. Considerable cost, however, may be associated with liming soils in other areas of the United

States (e.g., eastern and southeastern states). Soils in

these regions tend to be naturally acidic, and may require relatively large amounts of limestone (12 to 20

t/ha, or 5 to 8 tons/ac [T/ac]) to maintain a proper soil

pH. In addition, the trend toward increased growth of

cash grain crops (corn, small grains) has resulted in

greater commercial fertilizer use, which generates acidity that can decrease soil pH.

While maintaining soil pH between 6.5 and 7.0 often is

desirable for optimum availability of essential plant nutrients, liming soils is not always necessary to achieve

desired crop growth. For example, excellent yields of

corn, soybeans, and wheat can be obtained at a soil pH

of 5.5 to 6.0. Many soils in most of the western United

States contain free calcium carbonate, which naturally

maintains a pH of about 8.3. For these types of soils, trace

element deficiencies rather than toxicities are a major

concern. Therefore, the best advice is to involve agronomic expertise to help manage soil pH at the recommended levels for soils and crops in your state or area. 

Soil pH is buffered by inorganic and organic colloids.

Thus, it does not increase immediately after limestone

applications, nor does it decrease soon after sewage

sludge or N fertilizer additions. If soil pH is less than the

desired level, a lime requirement test can be used to

estimate the amount of agricultural limestone required

to adjust the pH. Soil pH monitoring is discussed further

in Chapter 13.

64
7.2.3 Special Considerations for Arid Lands

7.2.3.1 Crop Land

In arid regions (all U.S. lands west of the 100th meridian,

with less than 20 inches of rain annually), sewage

sludge additions can be a significant source of nutrients

and organic matter. Sludge application can often improve soil physical properties such as water-holding

capacity, infiltration, and aeration (Burkhardt et al.,

1993). Sludge application can also increase the protein

content of crops such as winter wheat compared to sites

receiving commercial N fertilizer (Ippolito et al., 1992).

In arid and semi-arid climates, evapotranspiration exceeds precipitation, minimizing downward migration of

NO3-N. In low-rainfall and irrigated areas, sewage

sludge constituents such as soluble salts and boron (B)

should also be considered when determining sludge

application rates. High concentrations of salt in the plow

layer can impair germination and early seedling growth

(Jacobs et al., 1993). Excessive salt can also cause soil

dispersion, reducing water infiltration rates and soil

aeration and causing soil structure changes that make

tilling more difficult (Jacobs et al., 1993).

Generally, additions of salts by sewage sludge applications at agronomic rates will be low enough to avoid any

salt injury to crops. In dry climates, however, sewage

sludge can be a source of additional salts to the soilplant system, as can other fertilizers, manures, etc. Salt

sources must be properly managed if optimum crop

growth is to be achieved. Therefore, guidance from land

grant universities or other local sources of agronomic

information should be sought to help manage soluble

salt levels in soils.

7.2.3.2 Rangeland

Application of sewage sludge to rangeland (open land

with indigenous vegetation) is considered agricultural

land application under the Part 503 regulation. Much of

the arid and semiarid rangelands in the western and

southwestern United States have been degraded by

overgrazing, fires, wind erosion, and single resource

management practices. Sewage sludge application to

these lands can enhance the soil and vegetation

(Aguilar et al., 1994). Benefits can include increased

rangeland productivity; improved forage quality; increased rainfall absorption and soil moisture; reduced

runoff; increased germination and populations of favorable grasses; less competition from invading shrubs and

weeds; and decreased erosion potential (Fresquez et

al., 1990; Pierce et al., 1992; Peterson and Madison,

1992). In addition, the remote locations of most arid

rangeland sites minimizes public concerns about odors,

vectors, and traffic. Table 7-1 describes projects in which

sewage sludge was applied to arid rangelands.

As Table 7-1 shows, various studies concur that sewage

sludge application to rangelands can improve plant productivity without adversely impacting the environment.

The studies vary, however, regarding what application

rates of sewage sludge are optimum to use. A study in

Fort Collins, Colorado, reported that an application rate

of 4.5 mg/ha (2 dry T/ac) would enhance vegetative

growth with minimum excess NO3-N concentrations in

soil (RDB and CDM, 1994), and also indicated that N

levels in soil did not increase at a soil depth of 12 inches

as application rates increased (Gallier et al., 1993). A

study in the Rio Puerco Watershed in New Mexico indicated that leaching from saturated flow would not be

expected to occur below 1.5 m (5 ft) in similar soils in

this semiarid environment (Aguilar and Aldon, 1991).

Another study in Wolcott, Colorado, reported potential

NO3-N in surface water runoff at application rates above

20 mg/ha (9 dry T/ac), while a study at the Sevilleta

National Wildlife Refuge in New Mexico reported a reduction in surface water runoff at an application rate of

45 mg/ha (20 dry T/ac), with NO3-N, copper (Cu), and

cadmium (Cd) concentrations in the runoff below state

limits for ground water and for livestock and wildlife watering areas (Aguilar and Aldon, 1991).

A key to successful sewage sludge application on arid

rangelands is minimizing the disturbance of soil and

vegetation. Once the plant cover is disturbed, recovery

is very slow in the arid conditions, leaving the rangeland

vulnerable to erosion and weed invasion (Burkhardt et

al., 1993). Section 7.3.1 below discusses sludge application methods suitable for arid rangelands. 

7.3 Application Methods and Scheduling 

7.3.1 Application Methods

Methods of sewage sludge application chosen for agricultural land depend on the physical characteristics of

the sludge and soil, as well as the types of crops grown.

Liquid sewage sludge can be applied by surface spreading or subsurface injection. Surface application methods

include spreading by farm tractors, tank wagons, special

applicator vehicles equipped with flotation tires, tank

trucks, portable or fixed irrigation systems, and ridge

and furrow irrigation.

Surface application of liquid sludge by tank trucks and

applicator vehicles is the most common method used for

agricultural croplands, particularly when forage crops

are grown. Surface application of liquid sludge is normally limited to soils with less than a 6 percent slope.

After the sludge has been applied to the soil surface and

allowed to partially dry, it is commonly incorporated by

plowing or other tillage options prior to planting the crop

(i.e., corn, soybeans, small grains, cotton, other row

crops), unless minimum or no-till systems are being used.

Ridge and furrow irrigation systems can be designed to

65
apply sewage sludge during the crop growing season.

Spray irrigation systems generally should not be used

to apply sludge to forages or to row crops during the

growing season, although a light application to the stubble of a forage crop following a harvest is acceptable.

The adherence of sludge to plant vegetation can have

a detrimental effect on crop yields by reducing photosynthesis. In addition, spray irrigation tends to increase

the potential for odor problems and reduces the aesthetics at the application site, both of which can lead to

public acceptability problems.

Liquid sewage sludge can also be injected below the soil

surface, and injection generally is the preferred method

when gaining public acceptance. Available equipment

includes tractor-drawn tank wagons with injection

shanks (originally developed for liquid animal manures)

and tank trucks fitted with flotation tires and injection

shanks (developed for sludge application). Both types of

equipment minimize odor problems and reduce ammonia volatilization by immediate mixing of soil and sludge.

Sludge can be injected into soils with up to 12 percent

slopes. Injection can be used either before planting or

after harvesting most crops but is likely to be unacceptable for forages and sod production. Some injection

shanks can damage the sod or forage stand and leave

deep ruts in the field. Equipment with specialized injection shanks has been developed that will not damage

the growth of forage and sod crops.

Dewatered sewage sludge can be applied to cropland

by equipment similar to that used for applying animal

manures, but more sophisticated equipment has been

developed with high flotation tires and improved application design. Typically, the dewatered sludge will be

surface-applied and then incorporated by plowing or

another form of tillage. Incorporation, however, is not

used when dewatered sludge is applied to growing forages or to minimum- or no-till land. Sewage sludge

application methods, some of which can be used to

meet Part 503 vector attraction reduction requirements

(i.e., incorporation and injection), are discussed in

greater detail in Chapter 14.

A number of agricultural land application programs using

private farmland have found that soil compaction is an

important concern of farmers (Jacobs et al., 1993).

Therefore, care should be taken to manage the application equipment and methods (e.g., use wide-flotation

tires, deep till the staging area following application) to

prevent soil compaction (Jacobs et al., 1993).

Table 7-1. Summary of Research on Sewage Sludge Application to Rangeland (Adapted From U.S. EPA, 1993)

Geographic Location Plant Community

Mean Precip.

(cm/yr)

Sludge Loading

(mg/ha, dry) Significant Results of Study

Wolcott, CO western wheatgrass,

alkali bluegrass,

Indian ricegrass

25 0, 4.5, 9, 13, 18,

22, 27, 31, 36

Increase in species diversity with sewage

sludge application. Increase in nitrogen

concentration in soil profile with increasing

application rates, but did not penetrate below

90 cm (about 3 ft). Application rates above

20 mg/ha (9 T/ac) pose a potential hazard for

surface water contamination by nitrates (Gallier

et al., 1993; Pierce, 1994).

Meadow Springs Ranch,

Fort Collins, CO

blue grama,

buffalo grass,

western wheatgrass,

fringed sage

38 0, 2.2, 4.5, 11,

22, 34

Maximum vegetative growth was obtained at

an application rate of 11 mg/ha (5 T/ac). An

application rate of 4.5 mg/ha (2 T/ac) of

sewage sludge would increase vegetative

growth and minimize excess nitrate

concentrations in soil (RDB and CDM, 1994).

Nitrogen levels in soil ceased to increase

below 1 ft (Gallier et al., 1993).

Sevilleta National

Wildlife Refuge, NM

blue grama,

hairy grama

20-25 45 Reduction in runoff volumes due to increased

water absorption and surface roughness

resulting from sewage sludge application.

Nitrate concentrations in runoff were well below

recommended NM standard of 10 mg-N/l

(Aguliar and Loftin, 1991; Aguilar et al, 1992).

Rio Puerco

Watershed, NM

blue grama,

snakeweed

25 0, 22.5, 45, 90 An increase of 2 to 3 fold in blue grama forage

production was found for sludge applications of

45 and 90 mg/ha (20 and 40 T/ac). A decrease

in snakeweed yield was found, allowing forage

to increase (Fresquez et al., 1991). Sludge

applications of 22.5 and 45 mg/ha (10 and 20

T/ac) produced the most favorable vegetative

growth responses, whereas applications of 90

mg/ha (40 T/ac) did not significantly increase

yield (Fresquez et al., 1990). 

66
On arid rangelands, it is important to minimize the disturbance of the soil surface and existing perennial plant

cover. Examples of sewage sludge application to rangeland are shown in Table 7-1. Carlile et al. describe the

following application method as one that can be used for

arid rangelands:1

• Shred brush species with an agricultural shredder at a

height that does not disturb underlying grass vegetation.

• Apply the sewage sludge uniformly over the soil surface

with a tractor-drawn agricultural manure spreader.

• Pass over the land with a range dyker and roller to

make small pits and slits in the soil without significantly disturbing the grass cover.

7.3.2 Scheduling

The timing of sewage sludge land applications must be

scheduled around the tillage, planting, and harvesting

operations for the crops grown and also can be influenced by crop, climate, and soil properties. Sewage

sludge cannot be applied during periods of inclement

weather. Table 7-2 presents a general guide regarding

when surface and subsurface applications of sludge are

possible for crops in the North Central States. Local

land-grant universities, extension personnel, or others

with agronomic expertise can provide similar information

for each state or locality.

Under the Part 503 regulation, application of sewage

sludge to agricultural land that is flooded, frozen, or

snow-covered is not prohibited, but the applier must

ensure that no sludge enters wetlands or surface waters

(except as allowed in a Clean Water Act Section 402 or

404 permit). Soil moisture is a major consideration affecting the timing of sludge application. Traffic on wet

soils during or immediately following heavy rainfalls may

result in compaction and may leave deep ruts in the soil,

making crop production difficult and reducing crop

yields. Muddy soils also make vehicle operation difficult

and can create public nuisances by carrying mud out of

the field and onto roadways.

Split applications of sewage sludge may be required for

rates of liquid sludge in excess of 4 to 7 t/ha (2 to 3 dry

T/ac), depending on the percent solids content. Split

application involves more than one application, each at

a relatively low rate, to attain a higher total rate, when

the soil cannot receive the volume of the higher rate at

one time. For example, if a sludge contains 4 percent

solids, the volume of sludge applied at a rate of 11 t/ha

(5 dry T/ac) is approximately 114,000 L/ha (30,000

gal/ac, or about 1.1 acre inch [ac-in]). Application rates

much above 0.3 ac-in at one time will likely result in

runoff or ponding, depending on soil conditions (e.g.,

infiltration rate, water-holding capacity) and slopes.

Table 7-2. General Guide to Months Available for Sewage Sludge Application for Different Crops in North Central Statesa

Small Grainsb

Month Corn Soybeans Cottonc Foragesd Winter Spring

January Se S S/I S C S

February S S S/I S C S

March S/I S/I S/I S C S/I

April S/I S/I P, S/I C C P, S/I

May P, S/I P, S/I C C C C

June C P, S/I C H, S C C

July C C C H, S H, S/I H, S/I

August C C C H, S S/I S/I

September C H, S/I C S S/I S/I

October H, S/I S/I S/I H, S P, S/I S/I

November S/I S/I S/I S C S/I

December S S S/I S C S

a

 Application may not be allowed due to frozen, flooded, or snow-covered soils.

b

 Wheat, barley, oats, or rye.

c

 Cotton, only grown south of southern Missouri.

d

 Established legumes (alfalfa, clover, trefoil, etc.), grass (orchard grass, timothy, brome, reed canary grass, etc.), or legume-grass mixture.

e

 S = surface application

S/I = surface/incorporation application

C = growing crop present; application would damage crop

P = crop planted; land not available until after harvest

H = after crop harvested, land is available again; for forages (e.g., legumes and grass), availability is limited and application must be light

 so regrowth is not suffocated

1

 Carlile, B.L., R.E. Sosebee, B.B. Wester, and R. Zartman. Beneficial use

of biosolids on arid and semi-arid rangeland. Draft report.

67
Thus, if rates such as 1.1 ac-in are desired, three or four

separate applications will probably be needed.

Subsurface injection will minimize runoff from all soils

and can be used on greater slopes. Injection application

rates in one pass, however, are not much greater than

rates with surface application. Injection should be made

perpendicular to slopes to avoid having liquid sludge run

downhill along the injection slits and pond at the bottom

of the slopes. As with surface application, the drier the

soil, the more liquid it will be able to absorb, thereby

minimizing any movement downslope.

7.3.3 Storage

Storage facilities are required to hold sewage sludge

during periods of inclement weather, equipment breakdown, frozen or snow-covered ground, or when land is

unavailable due to growth of a crop. Liquid sewage

sludge can be stored in digesters, tanks, lagoons, or

drying beds; dewatered sewage sludge can be stockpiled. Volume requirements will depend on individual

systems and climate and can be estimated from the

following data:

• Sewage sludge volume and physical characteristics

• Climatic data

• Cropping data

Chapter 14 contains additional information on evaluating sludge storage needs.

Some states specify climatic restrictions when sewage

sludge applications are prohibited (e.g., on days when

more than 2.5 mm [0.1 in.] of rainfall occurs). For a

specific site, the average number of days in each month

with these or other weather conditions can be obtained

from the National Climatic Center, NOAA, Asheville,

North Carolina 28801, or from local sources.

Except for forages, sewage sludge application to cropland usually is limited to those months of the year when

a crop is not present. The application schedule shown

in Table 7-2 is a general guide for common crops in the

North Central States; similar information can be obtained for other states, as discussed in Section 7.3.2.

The availability of sites used to grow several different

crops will help facilitate the application of sewage sludge

throughout the year. For example, a number of fields

containing forages, corn, and winter wheat would allow

sludge application during nearly all months of the year.

7.4 Determining Sewage Sludge

Application Rates for 

Agricultural Sites

Sewage sludge application rates are calculated from

data on sludge composition, soil test information, N and

P fertilizer needs of the crop grown, and concentrations

of trace elements. In essence, this approach views sewage sludge as a substitute for conventional N or P

fertilizers in crop production. The number of years that

sewage sludge application may be limited, based on

Part 503 cumulative pollutant loading rate limits for metals, is discussed below in Section 7.4.4.3.

The general approach for determining sewage sludge

application rates on agricultural cropland can be summarized as follows:

• Nutrient requirements for the crop selected are based

on yield level and soil test data. If sewage sludge has

been applied in previous years, fertilizer recommendations are corrected for carry-over of nutrients

added by previous sludge additions.

• Annual sewage sludge application rates are calculated based on N crop needs, P crop needs, and Part

503 annual pollutant loading rate limits, where applicable (bagged sludge).

• Supplemental fertilizer is determined from N, P, and

K needed by the crop and amounts of N, P, and K

provided by sewage sludge application.

• Sewage sludge applications are terminated when a Part

503 cumulative pollutant loading rate limit is reached if

applicable (see Section 7.4.4.3 and Chapter 3).

The majority of sewage sludge contains roughly equal

amounts of total N and P, while crop requirements for N

are generally two to five times greater than those for P.

A conservative approach for determining annual sewage

sludge application rates would involve applying sewage

sludge to meet the P rather than N needs of the crop.

Some states require this approach, particularly when

soil fertility test levels for P are high. With this approach,

farmers would need to supplement sludge N additions

with N fertilizer to achieve the expected crop yield.

7.4.1 Part 503 Agronomic Rate for N and

Pollutant Limits for Metals

The Part 503 rule requires that sewage sludge be land

applied at a rate that is equal to or less than the agronomic rate for N at the application site (i.e., the rate that

will provide the amount of N needed by the crop or

vegetation while minimizing the amount of N that passes

through the root zone and enters the ground water).

Additional Part 503 requirements include:

• Sewage sludge cannot be land applied unless the

trace element (metal) concentrations in the sludge

are below the Part 503 ceiling concentrations.

• The sewage sludge must meet either (1) the pollutant

concentration limits specified in Table 3 of Part 503 or

(2) the Part 503 cumulative pollutant loading rate

(CPLR) limits for bulk sewage sludge or the annual

pollutant loading rate (APLR) limits for bagged sewage

68
sludge (see Chapter 3). If the sewage sludge meets

the pollutant concentration limits or APLR limits, Part

503 does not require metal loadings to be tracked.

• The sewage sludge must also meet required Part 503

pathogen reduction alternatives and vector attraction

reduction options (see Chapter 3).

Generally, the agronomic rate is the limiting factor regarding application rates for sewage sludge rather than

Part 503 pollutant limits. Only when a CPLR limit is

being met and the cumulative loading rate at a site is

approaching the CPLR limit will the Part 503 pollutant

limits become the limiting factor for the sewage sludge

application rate. Section 7.4.4.3 discusses how to calculate sewage sludge application rates based on the

CPLRs. Because the Part 503 rule requires that the

maximum annual application rates for bagged sewage

sludge, based on APLRs, be clearly marked on each

bag, calculation of the APLR is not covered here.

The general approach for calculating sewage sludge

application rates in this manual requires developing as

accurate a mass balance for N in the sewage sludge

and soil-crop system as possible. Equations required for

calculating a N mass balance are relatively simple;

choosing reasonable input values for calculations, however, is more challenging. For initial calculations, “typical” and “suggested” values for all necessary parameters

are provided in tables throughout the manual. Site-specific

data or the best judgement of individuals familiar with the

N dynamics of the soil-crop system at the site should

always be used in preference to “typical” values. Particularly for large-scale projects, laboratory mineralization

studies should be considered (see Chapter 13), using

samples of the actual sewage sludge to be applied and

soil materials from the site, because application rate calculations are quite sensitive to the assumed annual N

mineralization percentage used.

7.4.2 Crop Selection and Nutrient

Requirements

The crops grown in an area will influence the scheduling

and methods of sewage sludge application. Utilizing the

cropping systems already present will usually be advantageous, since these crops have evolved because of

local soil, climatic, and economic conditions. Since sewage sludge applications typically are limited by the N

requirements of the crop, high N-use crops, such as

forages, corn, and soybeans, will minimize the amount

of land needed and the costs associated with sludge

transportation and application. However, applying

sludge to meet N needs of crops will add excess P, and

eventually rates may need to be reduced to manage

sludge P additions. Therefore, not only is it good practice to use fields with a mixture of crops, but the prudent

manager of a land application program will continue to

identify additional land areas that can be held in reserve.

Fertilizer recommendations for crops are based on the

nutrients needed to achieve the desired yield of the crop

to be grown and the capacity of the soil to provide the

recommended plant-available nutrients. The amounts of

fertilizer N, P, and K required to attain a given crop yield

have been determined experimentally for numerous

soils in each region of the United States. Crop response

to fertilizer nutrients added has been related to soil test

levels for P, K, Mg, and several of the essential trace

elements (Zn, Cu, Fe, Mn). Accurate measurement of

plant-available N in soil is difficult and also dependent

on climate. As a result, fertilizer N recommendations for

a particular locality are usually developed using a combination of (1) guidelines developed by State Agricultural

Experiment Stations and the Cooperative Extension

Service, based on historical experience with crop yields

on different soil types using different management practices; (2) soil test data; and (3) estimates of residual N

carryover from previous applications of sewage sludge,

animal manures, or nitrogen-fixing crops, such as alfalfa

and soybeans.

As an illustration of the general approach used to determine nutrient needs, typical relationships between yield

level, nitrogen required, soil test levels for plant-available P and K, and fertilizer requirements for P and K are

shown in Tables 7-3 through 7-6 for various crops in the

Midwest. The amounts of supplemental P and K needed

by crops increase as the yield level increases for a fixed

range of existing plant-available P and K in the soil.

Conversely, fertilizer needs decrease at a specific yield

level as soil test levels for P and K increase.

Data such as that presented in Table 7-7 can be used

to estimate the amount of plant-available N that will be

mineralized from sludge organic N applied initially and

from organic N estimated to be remaining from previous

sewage sludge applications. These estimates can then

be used to adjust the fertilizer N recommendations for

the crops to be grown. As has been discussed, however,

the amounts of residual organic N from previous sludge

applications that may be mineralized depend on many

factors. Thus, guidance as to how to best estimate these

quantities of mineralizable N, as well as information on

fertilizer recommendations, should be obtained from the

Agricultural Experiment Stations and Extension Service

of land-grant universities.

7.4.3 Calculating Residual N, P, and K

When sewage sludge is applied to soil each year, the N,

P, and K added in previous years that are not taken up

by crops can be partially available during the current

cropping season. Sewage sludge applied at a rate to

meet the N needs of a crop typically will result in increased soil P levels. Application of sewage sludge

containing high K levels could increase soil K, although

69
Table 7-3. Representative Fertilizer Recommendations for Corn and Grain Sorghum in the Midwest

Fertilizer P (P2O5) and K (K2O) Recommended for Soil Fertility* †

Yield 

(Metric tons/ha)

Nitrogen To 

Be Applied

(kg/ha) Fertilizer Very Low Low Medium High Very High

(kg/ha)

6.7-7.4 134 P (P2O5): 49 (113) 35 (80) 25 (56) 15 (33) 0

K (K2O): 93 (112) 65 (78) 47 (57) 28 (34) 0

7.4-8.4 157 P (P2O5): 54 (123) 39 (90) 29 (67) 15 (33) 0

K (K2O): 112 (135) 84 (101) 56 (67) 28 (34) 0

8.4-10.1 190 P (P2O5): 59 (136) 45 (103) 29 (67) 20 (46) 4 (10)

K (K2O): 140 (169) 112 (135) 65 (78) 37 (45) 0

10.1-11.8 224 P (P2O5): 64 (146) 49 (113) 35 (80) 25 (56) 4 (10)

K (K2O): 167 (201) 130 (157) 84 (101) 56 (67) 0

11.8-13.4 258 P (P2O5): 74 (169) 59 (136) 39 (90) 25 (56) 4 (10)

K (K2O): 186 (224) 149 (179) 112 (135) 74 (89) 0

* Soil fertility test levels are as follows:

Table 7-4. Representative Fertilizer Recommendations for Soybeans in the Midwest

Fertilizer P (P2O5) and K (K2O) Recommended for Soil Fertility* †

Yield 

(Metric tons/ha)

Nitrogen To

Be Applied

(kg/ha) Fertilizer Very Low Low Medium High Very High

(kg/ha)

2.0-2.7 157 P (P2O5): 29 (67) 25 (56) 20 (46) 15 (33) 0

K (K2O): 99 (119) 74 (84) 47 (57) 37 (45) 0

2.7-3.4 196 P (P2O5): 39 (90) 35 (80) 25 (56) 15 (33) 0

K (K2O): 112 (135) 84 (101) 56 (67) 56 (67) 0

3.4-4.0 235 P (P2O5): 49 (113) 84 (101) 35 (80) 20 (46) 0

K (K2O): 140 (169) 112 (135) 84 (101) 56 (67) 0

4.0-4.7 274 P (P2O5): 59 (136) 49 (113) 39 (90) 25 (56) 10 (23)

K (K2O): 167 (201) 140 (169) 112 (135) 74 (89) 0

>4.7 336 P (P2O5): 59 (136) 49 (113) 39 (90) 25 (56) 10 (23)

K (K2O): 186 (224) 158 (190) 121 (146) 74 (89) 19 (23)

* See Table 7-3 for definition of soil fertility test levels.

†

 Amounts of P2O5 and K2O shown in parentheses.

 1 kg/ha of fertilizer = 0.89 lb/ac

 1 metric ton/ha of crop yield = 15.3 bu/ac.

Soil Test kg/P/ha kg/K/ha

Very low 0 to 11 0 to 88

Low 12 to 22 89 to 165

Medium 23 to 33 166 to 230

High 34 to 77 231 to 330

Very high 78+ 331+

†

 Amounts of P2O5 and K2O are shown in parentheses.

 1 kg/ha of fertilizer = 0.89 lb/ac

 1 metric ton/ha of crop yield = 15.3 bu/ac

70
Table 7-6. Representative Fertilizer Recommendations for Forages in the Midwest

Fertilizer P (P2O5) and K (K2O) Recommended for Soil Fertility* †

Yield 

(Metric tons/ha)

Nitrogen To

Be Applied

(kg/ha) Fertilizer Very Low Low Medium High Very High

(kg/ha)

< 1.8 112 P (P2

O5): 49 (113) 39 (90) 25 (56) 15 (33) 10 (23)

K (K2

O): 224 (270) 186 (224) 140 (169) 74 (89) 0

2.2-2.7 224 P (P2

O5): 59 (136) 49 (113) 35 (80) 25 (56) 20 (46)

K (K2

O): 336 (405) 280 (337) 224 (270) 168 (202) 112 (135)

> 2.7 390 P (P2

O5): 69 (159) 59 (136) 45 (103) 35 (80) 25 (56)

K (K2

O): 448 (540) 392 (472) 336 (405) 280 (337) 224 (270)

* See Table 7-3 for definition of soil fertility test levels.

†

 Amounts of P2O5 and K2O are shown in parentheses.

 1 kg/ha - 0.89 lb/ac

1 mt/ha - 0.45 T/ac

Table 7-5. Representative Fertilizer Recommendations for Small Grains in the Midwest

Fertilizer P (P2O5) and K (K2O) Recommended for Soil Fertility* †

Yield

(Metric tons/ha)

Nitrogen To

Be Applied

(kg/ha) Fertilizer Very Low Low Medium High Very High

(kg/ha)

WR:1.9-2.8# 62 P (P2

O5): 45 (103) 29 (67) 15 (33) 10 (23) 10 (23)

WR:2.8-3.4 73 P (P2

O5): 59 (136) 45 (103) 29 (67) 15 (33) 10 (23)

WR:3.4-4.0 84 P (P2

O5): 59 (136) 45 (103) 29 (67) 15 (33) 10 (23)

WR:4.0-4.6 95 P (P2

O5): 69 (159) 54 (123) 45 (103) 29 (67) 10 (23)

WR:>4.6 106 P (P2

O5): 69 (159) 54 (123) 45 (103) 29 (67) 10 (23)

* See Table 7-3 for definition of soil fertility test levels.

†

 Amounts of P2O5 and K2O are shown in parentheses.

# WR = Wheat and Rye.

1 kg/ha of fertilizer = 0.89 lb/ac.

1 metric ton/ha of crop yield = 14.3 bu/ac for wheat and rye.

71
agronomic rates (for N) of sewage sludge usually will

add K at levels less than crop needs.

The contribution of residual N carryover to plant-available N can be significant when sewage sludge is

applied each year. Although the largest percentage of

mineralizable organic N is converted to inorganic N

during the year that the sludge is applied, the continued decomposition of organic N in succeeding years

can provide some additional plant-available N for crop

growth. The amount of N mineralized in sludgetreated soils is dependent on the type of sludge treatment processes used, the ratio of inorganic to organic

N in the sludge, and the amount of organic N applied

in previous years.

The approach proposed for evaluating residual N, P, and

K from previous sewage sludge applications is as follows:

• P and K—Assume that 50 percent of the P and 100

percent of the K applied are available for plant uptake

in the year of application. These quantities of P and

K can be credited against fertilizer recommendations.

Any P and K in excess of plant needs will contribute

to soil fertility levels that can be regularly monitored

and taken into account when determining fertilizer

recommendations in succeeding years.

• N—Plant-available N (PAN) that may be mineralized

from residual sludge organic N can sometimes be

estimated by using soil tests (see Chapter 6). However, estimating PAN by using mineralization factors

recommended by land-grant universities or state

regulatory agencies is more common. The largest

portion of organic N in sewage sludge is converted

to inorganic N during the first year after application

to the soil. After the first year, the amount of N mineralization decreases each year until it stabilizes at

about 3 percent, a rate often observed for stable

organic N fractions in soils. Once the 3 percent level

has been reached, any additional quantities of PAN

will not be significant enough to credit against the

fertilizer N recommendation.

Table 7-7 suggests a decay sequence where the

amount of N mineralized decreases by about 50 percent each year until the 3 percent rate is reached.

Using anaerobically digested sewage sludge as an

example, if 20 percent of the organic N was mineralized during the first year, the amounts released in

years 2 and 3 would be 10 and 5 percent, respectively, of the organic N remaining (see Table 7-7).

After year 3, the mineralization rate decreases to the

background rate for soil organic matter, so no additional credit for residual sludge organic N is calculated. This decay sequence may or may not be the

most appropriate one to use for your state or location,

but it will be used to illustrate how mineralizable N can

be calculated to estimate PAN credits.

7.4.4 Calculation of Annual Application Rates

Recommended annual rates of sewage sludge application on cropland are based on the N or P requirements

of the crop grown, the N and P levels in the sludge, and

the metal concentrations in the sludge for which pollutant limits have been set in the Part 503 rule. As discussed in the previous section, the fertilizer N

recommendation for the crop and yield level expected

should be corrected for plant-available N mineralized

from prior sludge additions. The basic approach for

determining annual application rates of sewage sludge

involves using data on sewage sludge composition to

calculate maximum potential application rates based on

(1) crop N requirements, (2) crop P requirements, and

(3) Part 503 pollutant limits. In most cases, the actual

application rate will be selected from the following two

possibilities:

• The annual agronomic rate can be utilized to provide

recommended N needs until the Part 503 CPLR limits

for metals are reached, unless the sewage sludge

meets the pollutant concentration limits in Table 3 of

Part 503, in which case cumulative metal loadings do

not need to be tracked. (In some cases, this approach

may result in the accumulation of excess P in the soil,

Table 7-7. Estimated Mineralization Rates (Kmin) for Different Sewage Sludges (Adapted From Sommers et al, 1981)

Fraction (Kmin)* of Organic N Mineralized From the Following Sludges:

Time After Sewage Sludge

Application (Years)

Unstabilized Primary

and Waste

Aerobically

Digested

Anaerobically

Digested

Composted

0-1 0.40 0.30 0.20 0.10

1-2 0.20 0.15 0.10 0.05

2-3 0.10 0.08 0.05 -†

3-4 0.05 0.04 - -

* Fraction of the sludge organic N (Org-N) initially applied, or remaining in the soil, that will be mineralized during the time interval shown. Kmin

values are provided as examples only and may be quite different for different sewage sludges, soils, and climates. Therefore, site-specific

data, or the best judgement of individuals familiar with N dynamics in the soil-plant system, should always be used in preference to these

suggested Kmin values.

†

 Once the mineralization rate becomes less than 3% (i.e., 0.03), no net gain of PAN above that normally obtained from the mineralization of

soil organic matter is expected. Therefore, additional credits for residual sludge N do not need to be calculated.

72
which can increase the potential for P entering

streams and lakes through surface erosion).

• In some states, the annual rate may be limited to a

rate where sludge P is equal to fertilizer P recommendations or the P removed by the crop. Nitrogen

may be applied at less than the crop N need. This P

rate could be followed as long as it did not exceed

the agronomic N rate or any Section 503 pollutant

loading limits for metals.

Another possibility is that the metals loadings at the site

are approaching a Part 503 CPLR limit, which may result

in an application rate that is less than the crop’s N or P

needs (i.e., sewage sludges that do not meet the Part

503 pollutant concentration limits for metals). Reaching

a CPLR limit terminates CPLR sewage sludge application to land, in which case other options, such as incineration or surface disposal, are likely to be more feasible.

Currently, however, a majority of sewage sludge in the

United States can meet Part 503’s pollutant concentration

limits. Thus, the nutrient requirements of a crop will likely

be the limiting factor rather than Part 503 pollutant limits.

The following section summarizes the basic calculations

used to determine sewage sludge application rates

based on N (Section 7.4.4.1) and P (Section 7.4.4.2),

and the estimated project life based on CPLR limits

(Section 7.4.4.3). The design example (Section 7.5)

provides additional illustrations of these calculations.

 7.4.4.1 Calculation Based on Nitrogen

As discussed previously, not all the N in sewage sludge

is immediately available to plants, since some is present

as organic N (Org-N), i.e., in microbial cell tissue and

other organic compounds. Organic N must be decomposed into mineral, or inorganic forms, such as NH4-N

and NO3-N, before it can be used by plants. Therefore,

the availability of Org-N for plants depends on the microbial breakdown of organic materials (e.g., sewage

sludge, animal manure, crop residues, soil organic matter, etc.) in soils.

The proportion of sludge Org-N that is mineralized in a

soil depends on various factors which influence immobilization and mineralization of organic forms of N

(Bartholomew, 1965; Harmsen and van Schreven, 1955;

Smith and Peterson, 1982; Sommers and Giordano,

1984). Schemes for estimating the amount of mineralizable N from organic fertilizers, like animal manure

and sewage sludge, have been suggested (Pratt et al.,

1973; Powers, 1975; Smith and Peterson, 1982; USDA,

1979; USEPA, 1975, 1983).

Estimates of mineralizable N using decay (decomposition) series are not precise, however, since the actual N

availability will depend on organic N composition, degree of treatment or stabilization of the sewage sludge

before land application, climate, soil conditions, and other

factors. Another approach to predicting N availability is

to model (mathematically) the transformations of N in

the soil. However, modeling has not yet been found to

be accurate enough to give more than a general estimate of N availability (Schepers and Fox, 1989). Nevertheless, management strategies must attempt to

balance the addition of plant-available N, provided by

land application of organic materials like sewage sludge,

with the needs of the crop. Otherwise, excess NO3-N

can be leached into groundwater by precipitation or poor

management of irrigation water (Keeney, 1989).

The plant-available N, or PAN, provided by sewage

sludge is influenced by several factors. Initially, the

quantity of total N in the sludge and the concentrations

of NO3-N, NH4-N and Org-N (which together make up

the total N) must be determined. Commonly, the concentration of Org-N is estimated by subtracting the concentration of NO3-N and NH4-N from the total N, i.e.,

Org-N = total N - (NO3-N + NH4-N). The NH4-N and

NO3-N added by sludge is considered to be as available

for plants to utilize as NH4-N and NO3-N added by fertilizer

salts or other sources of these mineral forms of N.

The availability of sewage sludge Org-N will depend on

the type of treatment or stabilization the sludge received.

Anaerobically digested sludge normally will have high

levels of NH4-N and very little NO3-N, while aerobically

digested sludge will have higher levels of NO3-N by

comparison. Composting and anaerobic digestion accomplishes greater stabilization of organic carbon compounds than aerobic digestion or waste activation. The

greater the stabilization, the slower the rate of mineralization of carbon compounds (containing Org-N from the

sewage sludge) and the lower the amounts of Org-N

released for plant uptake.

Differences between these various types of sewage

sludges can be seen in Table 7-7 which shows average

mineralization rates for the first through fourth year following a sludge application (Sommers et al., 1981).

These values, however, are averages only and can vary

significantly due to differences in the characteristics of

the sewage sludge, soil, and climate (i.e., temperature

and rainfall). For example, assuming adequate moisture

is available for microbial decomposition, increases in

temperature will increase the activity of microorganisms.

Therefore, mineralization rates are typically higher in the

summer months than in the winter months and higher in

the southern U.S. than in the northern states. Because

of these differences, calculating the agronomic rate

should be done on a site-specific basis. Using mineralization factors recommended by state regulatory agencies and land-grant universities that are based on

decomposition or N mineralization studies, computer

simulations that estimate decomposition, or documented field experience is advised.

73
The amount of PAN also will be affected by the amount

of NH4-N lost by volatilization of ammonia (NH3). Ammonia volatilization losses, when animal manure or sewage

sludge is applied to land, have long been recognized

(Adriano et al., 1974; Beauchamp et al., 1978, 1982;

Brunke et al., 1988; Christensen, 1986; Döhler and

Wiechmann, 1988; Hall and Ryden, 1986; Hoff et al.,

1981; Lauer et al., 1976; Rank et al., 1988; Reddy et al.,

1979; Terman, 1979; Vallis et al., 1982). Accurately estimating the extent of this loss is difficult, however, given

the variability in weather conditions that largely dictate

how fast volatilization will occur.

In addition to weather conditions, the method of sewage

sludge application, the length of time sewage sludge

remains on the soil surface prior to incorporation, and

the pH (e.g., lime content) of the sewage sludge also will

influence the potential for volatilization losses. High pH

in sewage sludge or soil will encourage the conversion

of NH4-N to NH3, resulting in a N loss to the atmosphere.

The longer the sludge remains on the soil surface and

is subjected to drying conditions, the greater the risk of

NH3 volatilization losses.

With injection of liquid sewage sludge, little NH3 should

be lost to volatilization, except possibly on coarsely

textured (sandy) soils. Volatilization losses, however,

should be considered for surface-applied liquid sewage

sludge that is later incorporated and for surface-applied

dewatered sewage sludge that is later incorporated or

remains on the surface. This N loss needs to be considered, or the amount of PAN reported to the farmer as

being applied will be overestimated.

Volatilization losses of NH4-N from animal manure also

are of interest in many states, and guidance often is

provided by state land-grant universities; thus, applicators of sewage sludge may want to seek similar guidance to estimate loss of NH4-N as NH3 during sewage

sludge application. In addition, several states (e.g., Virginia, Washington) have developed specific guidance on

NH3 volatilization from sewage sludge that takes into

account such factors as lime content of the sewage

sludge and the length of time sewage sludge remains

on the soil surface before it is incorporated.

For these reasons, Table 7-8 can serve as guidance for

estimating NH4-N losses as NH3. As indicated earlier,

these volatilization factors may not be the most appropriate for a specific site, so values should be obtained

from state regulatory agencies or state land-grant universities that are more site-specific for a particular location.

The inability to accurately estimate volatilization losses,

combined with the difficulty of estimating the amount of

mineralizable N, means that regulators need to remain

flexible regarding the methods used to estimate the

amount of PAN per dry ton of sewage sludge.

With these factors in mind, a number of steps can be used

to determine the agronomic rate (i.e., based on PAN).

These steps are summarized below and also are shown

on Worksheets 1 and 2 (see Figures 7-1 and 7-2):

1. Determine the fertilizer N recommendation for the

crop and yield level anticipated on the soil that is to

receive the sewage sludge application. (Since

legume crops can fix their own N, they usually will

not have a N fertilizer recommendation. Legume

crops, however, will utilize N that is applied as

fertilizer, manure, or sewage sludge, so N crop

removal values can be used to estimate the N

requirement for these crops.)

2. Subtract anticipated N credits from the recommended

fertilizer N rate, i.e., for other sources of N such as the

following:

a. Residual N left by a previous legume crop (legumes have the ability to fix N from the air, and

varying levels of N will be left in the soil when

legumes are replaced by another crop; land-grant

universities can provide appropriate credits that

should be used for a particular site).

b. Any N that has already been applied or will be

applied during the growth of the crop by fertilizer,

manure, or other sources that will be readily available for plants to use.

c. Any N that is anticipated to be added by irrigation water that will be applied during the growth

of the crop.

d. Any residual Org-N remaining from previous sewage sludge applications. As previously discussed,

Table 7-7 lists average mineralization rates, but

more sewage sludge-specific and site-specific information should be used when available. Experience

over time has shown that when agronomic rates

of sewage sludge are used, no additional PAN

above that normally obtained from soil organic

matter turnover is expected after 3-4 years. Therefore, calculating PAN credits for a sludge application beyond the third year is not recommended,

since these quantities are negligible. The chart in

Worksheet 1 and the mineralization factors in Table 7-7 can be used to estimate the PAN for years

2 and 3. An example calculation is included in

Worksheet 1.

Table 7-8. Volatilization Losses of NH4-N as NH3

Sewage Sludge Type and

Application Method

NH3 Volatilization 

Factor, Kvol

Liquid and surface applied 0.50

Liquid and injected into the soil 1.0

Dewatered and surface applied 0.50

74
Figure 7-1. Determining mineralized PAN from previous sludge applications.

75
Figure 7-1. Determining mineralized PAN from previous sludge applications (continued).

76
Figure 7-2. Determining agronomic N rate.

77
Figure 7-2. Determining agronomic N rate (continued).

78
e. Residual organic N remaining from any previous

animal manure application should be estimated.

Various decay schemes are used for manure applications by land-grant universities, so residual

N released from a previous manure application

can be estimated in a similar manner as for sewage sludge applications (i.e., step 2.d).

f. The combined residual N already present in the

soil or expected to be available for crops to use

can sometimes be estimated by the soil nitrate

test (e.g., inorganic N left from previous fertilizer,

manure, sludge, etc. applications; or credits given

for the mineralization of soil organic matter and

legume crop residues). The soil nitrate test can

be used in some states to estimate quantities of

NO3-N that may be present from previous fertilizer

N, manure, and/or sewage sludge applied and/or

from mineralization of N from legume crops and

soil organic matter. But because NO3-N can be

lost by leaching, the soil nitrate test must be used

with care in semi-humid and humid climates.

Therefore, guidance should be obtained from a

land-grant university for the proper credits to use.

 Note that if a soil nitrate test is used to estimate

residual N contributions, then estimates for steps

2.a, 2.d, and 2.e should not be included in the

summation done in step 2 on Worksheet 2.

3. Add any anticipated N losses due to denitrification,

immobilization, or chemical fixation of NH4

+ by

micaceous (i.e., mica-containing) clay minerals (use

only if approved by regulatory agency). Denitrification [i.e., the loss of NO3-N as nitrogen (N2) or

nitrous oxide (N2O) gases] and immobilization (i.e.,

the loss of NO3-N or NH4-N by incorporation into

organic compounds by the soil biology) can occur in

soils. For soils containing hydrous mica clay

minerals, some NH4

+ may become fixed within the

crystal lattices of these minerals in spaces normally

occupied by K+. If this occurs, NH4

+ is unavailable for

plant uptake unless mineral weathering occurs to

again release the NH4

+.

 The source of the NO3-N and NH4-N can be from

fertilizer, manure, etc. as well as sewage sludge

applications. Note that if fertilizer recommendations

are used which account for average losses due to

biological denitrification and immobilization or chemical

fixation of NH4

+, a separate credit for these processes

should not be used for this step. Therefore, adding

these anticipated N losses should not be done

unless justification is provided to the permitting

authority and approval is received.

4. Use Worksheet 2 to determine the adjusted fertilizer

N rate by subtracting “total N available from existing,

anticipated, and planned sources” (Worksheet step

2) from “total N requirement of crop” (Worksheet step

1). If a loss of available N by denitrification, immobilization or NH4

+ fixation is allowed (i.e., approved by

the state regulatory agency), this anticipated loss

can be added to the difference obtained when

subtracting the step 2 total from the step 1 amount

to obtain a final adjusted fertilizer N rate.

5. Determine the PAN/dry ton of sewage sludge for the

first year of application using the following equation:

PAN = NO3-N + Kvol (NH4-N) + Kmin (Org-N)

where:

PAN = plant-available N in lb/dry ton sewage

sludge

NO3-N = content of nitrate N in sewage sludge

in lb/dry ton

Kvol = volatilization factor, or fraction of NH4-N

not lost as NH3 gas to the atmosphere

NH4-N = content of ammonium N in sewage

sludge in lb/dry ton

Kmin = mineralization factor, or fraction of 

Org-N converted to PAN

Org-N = content of organic N in sewage sludge

in lb/dry ton, estimated by Org. N = 

total N - (NO3-N + NH4-N)

 Example: Assume liquid, aerobically digested

sewage sludge is to be incorporated into the soil

by direct injection (i.e., Kvol = 1.0). The suggested

mineralization rate in Table 7-7 is Kmin = 0.30 for

the first year. The chemical analysis of the sludge

shows NO3-N = 1,100 mg/kg, NH4-N = 1.1% and

total N = 3.4%, all on a dry weight basis, and

percent dry solids is 4.6%.

a. First convert concentrations to lb/dry ton:

 for NO3-N — 1,100 mg/kg x 0.002 = 2.2, or 2 lb/ton

(rounded to nearest whole lb)

 for NH4-N — 1.1% x 20 = 22 lb/ton

 for total N — 3.4% x 20 = 68 lb/ton

 for Org-N — 68 - (2 + 22) = 44 lb/ton

b. Calculate PAN:

 PAN = 2 + 1.0 (22 lb/ton) + 0.3 (44 lb/ton) =

2 + 22 + 13 = 37 lb/ton

6. Divide the adjusted fertilizer N rate (lb N/acre from step

4) by the PAN/dry ton sewage sludge (lb N/ton from

step 5) to obtain the agronomic N rate in dry tons/acre.

 Example: Assume the adjusted fertilizer N rate

from step 4 is 130 lb N/acre and the aerobically

digested sewage sludge from the example in step

79
5 above is used to provide crop N needs. What is

the agronomic N rate?

 Agronomic N rate = 130 lb N/acre 4 37 lb N/ton

= 3.5 dry tons/acre

7. This dry ton/acre rate can be converted to wet

gallons/acre, since this is the form in which the

sewage sludge will be applied:

 wet tons/acre = 3.5 dry ton/acre 4 4.6 dry ton/100

wet ton (i.e., 4.6% solids) = 76 wet ton/acre

This wet tonnage can then be converted to gallons/acre

by the following conversion:

 76 wet ton/acre x 2,000 lb/wet ton x

1 gallon/8.34 lb = 18,200 gallons/acre

This rate would be equivalent to about 2/3 acre-inch of

liquid (1 acre-inch = 27,150 gal), too much to apply in

one application. Probably 13,000-15,000 gal/acre is a

maximum amount that can normally be applied at one

time using injection.

7.4.4.2 Calculation Based on Phosphorus

The majority of P in sewage sludge is present as inorganic compounds. While mineralization of organic forms

of P occurs during decomposition of sludge organic

matter, inorganic reactions of P are of greater importance when considering sludge P additions. Because of

the predominance of inorganic P, therefore, the P contained in sewage sludge is considered to be about 50

percent as available for plant uptake as the P normally

applied to soils in commercial fertilizers (e.g., triple superphosphate, diammonium phosphate, etc.). As previously discussed, the P fertilizer needs of the crop to

be grown are determined from the soil fertility test for

available P and the yield of the crop. The agronomic P

rate of sewage sludge for land application can be determined by the following equations:

Agronomic P Rate = Preq 4 Avail. P2O5/dry ton

where:

Preq = the P fertilizer recommendation for the harvested crop, or

the quantity of P removed by

the crop,

Avail. P2O5 = 0.5 (total P2O5/dry ton)

Total P2O5/dry ton = %P in sludge x 20 x 2.3*

*2.3 is the factor to convert lb P to lb P2O5 (the ratio of the atomic weights of P2O5:P, i.e.,142:62).

For nearly all sewage sludge, supplemental N fertilization will be needed to optimize crop yields (except for

N-fixing legumes) if application rates are based on a

crop’s P needs.

7.4.4.3 Calculation Based on Pollutant

Limitations

The literature pertaining to trace element (metal) additions to the soil-plant system from sewage sludge applications is extensive, and several key references can

be a source of more in-depth discussions (Allaway,

1977; Berglund et al., 1984; CAST, 1976, 1980;

Chaney, 1973, 1983a, 1983b, 1984; Chaney and Giordano, 1977; Davis et al., 1983; L’Hermite and Dehandtschutter, 1981; Lindsay, 1973; Logan and Chaney,

1983; Melsted, 1973; Page et al., 1987; Ryan and

Chaney, 1993; Sommers and Barbarick, 1986; U.S.

EPA, 1974; Walsh et al., 1976). Potential hazards associated with trace element additions have mostly pertained to their accumulation in soils which may (1) lead

to a plant toxicity condition or (2) result in increased

uptake of trace elements into the food chain.

As discussed in Chapter 3, the pollutant limits established in the Part 503 regulation protect human health

and the environment from reasonably anticipated adverse effects of pollutants that may be present in sewage sludge.

Because most sewage sludges will likely contain pollutant concentrations that do not exceed the Part 503

“pollutant concentration limits” (see Chapter 3), pollutant loading limits will not be a factor in determining

annual sewage sludge application rates for these sewage sludges. For other sewage sludges that have pollutant concentrations that exceed one or more of the

Part 503 “pollutant concentration limits,” the Part 503

“cumulative pollutant loading rates” (CPLRs) discussed

in Chapter 3 and shown in Table 7-9 must be met;

CPLRs could eventually be the limiting factor for annual

Table 7-9. Part 503 Cumulative Pollutant Loading Rate

(CLPR) Limits

Loading Limits

Pollutant kg/ha lb/acre

Arsenic 41 37

Cadmium 39 35

Chromium 3,000a 2,700

Copper 1,500 1,300

Lead 300 270

Mercury 17 15

Molybdenum —a —

Nickel 420 380

Selenium 100 90

Zinc 2,800 2,500

a

 Chromium limits will most likely be deleted from Part 503. The CPLR

for Mo was deleted from Part 503 effective February 25,

1994. EPA will reconsider this limit at a later date.

80
sewage sludge applications (rather than the agronomic

rate of application).

For sewage sludge meeting Part 503 CPLRs, two equations are helpful for managing pollutant loadings to soils.

The first equation can be used to estimate the maximum

total quantity of sewage sludge permitted to be applied

to a soil, based on the CPLR and the pollutant concentration in the sewage sludge being considered:

Maximum sewage sludge allowed (dry tons/acre) =

lb/acre (CPLR) 4 0.002 (ppm pollutant)

where:

ppm pollutant = mg of pollutant per kg of dry sewage sludge.

After making this calculation for each of the 10 pollutants

regulated by Part 503, the lowest “total sewage sludge”

value should be used as the maximum quantity of sewage sludge allowed to be applied for that particular site.

The design example in Section 7.5 shows how this

equation is used.

A second equation, also illustrated in Section 7.5, can

be used to determine the individual pollutant loading

added by each sewage sludge application rate:

lb of pollutant/acre = sludge rate (dry tons/acre) x

0.002 (ppm pollutant)

A cumulative record of individual applications is then

kept for each field receiving sewage sludge that is meeting the CPLRs. When the cumulative amount of any one

regulated pollutant reaches its CPLR, no additional

CPLR sewage sludge can be applied.

7.4.5 Calculation of Supplemental N, P, and

K Fertilizer

Once the application rate of sewage sludge has been determined, the amounts of plant-available N, P, and K added by

the sludge should be calculated and compared to the fertilizer recommendation for the crop (and yield level) to be

grown. If the amount of one or more of these three nutrients

provided by the sewage sludge are less than the amount

recommended, then supplemental fertilizers will be needed

to achieve crop yields. Refer to the design example in

Section 7.5 for an illustration of how this is determined.

7.4.6 Use of Computer Models To Assist in

Determining Agronomic Rates

Computer modeling often can be useful for site-specific

evaluation of sewage-sludge-climate-soil-plant N dynamics at a particular location, generally with minimal

additional data collection.

Computer models that specifically model N budgets in

sewage sludge and soil-plant systems can provide sitespecific information on soil physical and hydrologic conditions and climatic influences on N transformations.

The Nitrate Leaching and Economic Analysis Package

(NLEAP) developed by Shaffer et al. (1991) allows

monthly and event-by-event approaches throughout the

year to compute water and N budgets. The NLEAP

software is included in the purchase of Managing Nitrogen for Groundwater Quality and Farm Profitability

(Follet et al., 1991), which also serves as an excellent

reference for information on parameters required for N

budget calculations. Four regional soil and climatic databases (Upper Midwest, Southern, Northeastern, and

Western) also are available on disk for use with NLEAP.

These materials can be obtained from:

Soil Science Society of America

Attn: Book Order Department

677 S. Segoe Road

Madison, WI 53711

608/273-2021; Book $36.00;

Regional Databases $10.00 each.

Current updates of the NLEAP program can be obtained

by sending original diskettes to:

Mary Brodahl

USDA-ARS-GPSR

Box E

Fort Collins, CO 80522

The computer model DECOMPOSITION (Gilmour and

Clark, 1988) is specifically designed to help predict sewage sludge N transformations based on sludge characteristics as well as soil properties and climate (organic

matter content, mean soil temperature, and water potential). Additional information on this model can be obtained from:

Mark D. Clark

Predictive Modeling

P.O. Box 610

Fayetteville, AR 72702

Finally, the CREAMS (Chemicals, Runoff, and Erosion

from Agricultural Management Systems) and GLEAMS

(Groundwater Loading Effects of Agricultural Management Systems) models, developed by the U.S. Department of Agriculture (Beasley et al., 1991; Davis et al.,

1990; Knisel, 1980), are other potentially useful models

to assist with site-specific management of sewage

sludge application programs.

81
7.5 Design Example of Sewage Sludge

Application Rate Calculations

The following detailed design example is for a midwestern city with 20 dry ton/day (18 mt/day) of sewage

sludge requiring land application. The sewage sludge

has undergone anaerobic digestion and has the following characteristics:

Climatological data were collected for the application

area as described in Chapter 5. Sewage sludge application will be limited during periods of high rainfall and

high soil moisture conditions because of the potential for

surface runoff and the inability to use sludge application

equipment. In addition, sludge application will not occur

during periods of extended subfreezing temperatures

due to frozen soils, as indicated by Part 503.

For this site, assume that:

• Annual sewage sludge applications cannot exceed the N

requirement for the crop grown, as required by Part 503.

• Soil pH will be maintained at levels recommended by

land-grant universities for the crop to be grown (or

as required by state regulatory agencies).

• If nutrient additions by the sewage sludge application

are not sufficient, supplemental fertilizer nutrients will

be used to optimize crop production.

• Routine soil fertility testing will be done to establish

fertilizer recommendations and lime requirements for

optimum crop growth.

• The sewage treatment plant regularly monitors

chemical composition of the sludge as required by

Part 503 and state regulatory agencies.

• Records are maintained as required by Part 503 and

state regulatory agencies.

Soils in the site area are generally sandy loams. Soil

fertility tests have been completed and soil pH is being

maintained as recommended. Crops grown in the area

include corn, soybeans, oats, wheat, and forages for hay

and pasture. For the 1995 growing season, one half of

the fields receiving sludge will be cropped with wheat

requiring 90 lb/ac (100 kg/ha) of available N per year,

and one half of the fields will be cropped with corn

requiring 190 lb/ac (210 kg/ha) of available N per year.

Crop fertilizer requirements were obtained from local

Cooperative Extension Service agents for anticipated yield

levels of 80 bu/ac for wheat and 160 bu/ac for corn grain.

The soil fertility tests indicated that available P levels in

the soil are medium, and that available K levels are low.

Assume that this anaerobically-digested sewage sludge

was previously applied to the fields in 1993 and 1994,

as shown in the following chart:

For the wheat field, sewage sludge will be applied in the

fall after soybeans are harvested and before the winter

wheat is planted in the fall of 1994. For the corn fields,

sewage sludge will be applied in the spring of 1995

before corn is planted. No other source of N, except for

residual N from the 1994 and 1993 sludge applications,

are planned for the corn field. The wheat field will have

a 30 lb/acre N credit from the preceding soybean crop

and a residual N credit for the 1993 sludge application.

No irrigation water will be used, and no manure applications have been made to either field.

The liquid sewage sludge will be surface applied after

soybean harvest before the soil is tilled, prior to the wheat

being planted. Incorporation of the sludge will be within 0-1

day, and experience with animal manure suggests that

30% of the NH4-N is typically lost by ammonia volatilization. Therefore, 70% will be conserved and available for

plants to use, so Kvol = 0.7. For the corn field, the liquid

sludge will be injected into the soil, so Kvol = 1.0.

7.5.1 Calculation of Agronomic N Rate for

Each Field

Mineralization of PAN from the Org-N in this anaerobically digested sewage sludge is assumed to be the

• Solids - 4.8 percent

• Total N - 3.9 percent

• NH4-N - 1.2 percent

• NO3-N - 200 mg/kg

• Total P - 1.9 percent

• Total K - 0.5 percent

• As - 8 mg/kg

• Cd - 10 mg/kg

• Cr - 130 mg/kg

• Cu - 1,700 mg/kg

• Pb - 150 mg/kg

• Hg - 2 mg/kg

• Mo - 14 mg/kg

• Ni - 49 mg/kg

• Se - 15 mg/kg

• Zn - 1,200 mg/kg

N P2O5 K2O

Crop Yield (bu/ac) (lb/ac/year)

Corn 160 190 60 140

Wheat 80 90 80 125

Sewage Sludge Rate

(% Org-N in sludge)

1995 Growing

Season 1994 1993

Corn 4.8 ton/acre

(2.8% Org-N)

2.6 ton/acre

(2.5% Org-N)

Wheat None 4.6 ton/acre

(2.5% Org-N)

82
same as the Kmin values in Table 7-7 suggest, i.e., 20%

the 1st year, 10% the 2nd, and 5% the 3rd. Since the

NO3-N content is negligible (< 1lb/ton), it is not included

for calculating the PAN for this sewage sludge.

Total N = 3.9% x 20 = 78 lb/ton

NO3-N = 200/kg x 0.002 = 0.4 lb/ton

NH4-N = 1.2% x 20 = 24 lb/ton

Org-N = 78 - 24 = 54 lb/ton

For the wheat field where sewage sludge is to be surface applied:

PAN = Kvol (NH4-N) + Kmin (Org-N) =

0.7 (24 lb/ton) + 0.20 (54 lb/ton) =

17 + 11 =

28 lb/ton

For the corn field where sludge is to be injected:

PAN = Kvol (NH4-N) + Kmin (Org-N) =

1.0 (24 lb/ton) + 0.20 (54 lb/ton) =

24 + 11 =

35 lb/ton

To calculate the residual N mineralized from previous

sewage sludge applications, the Worksheet 1 chart is

completed for each field, as shown in Figure 7-3. As

indicated in Section 7.5 above, the wheat field had

sewage sludge applied in 1993, and the corn field received sludge applications in 1993 and 1994.

For the wheat field, Org-N originally applied in 1993 was:

Org-N = 4.6 ton/acre x 20 (2.5% Org-N) =

4.6 ton/acre x 50 lb/ton = 230 lb Org-N/acre

For the corn field, Org-N originally applied in 1993 and

1994 was:

1993: Org-N = 2.6 ton/acre x 20 (2.5% Org-N) =

2.6 ton/acre x 50 lb/ton =

130 lb Org-N/acre

1994: Org-N = 4.8 ton/acre x 20 (2.8% Org-N) =

4.8 ton/acre x 56 lb/ton =

270 lb Org-N/acre

Therefore, as the Worksheet 1 charts show (Figure 7-3),

the PAN credit to use in Worksheet 2 for the wheat field

due to previous sewage sludge application is 8 lb N/acre.

The PAN credit to use in Worksheet 2 for the corn field due

to previous sewage sludge applications is 27 lb N/acre.

The agronomic N rate can now be calculated for the

wheat field using Worksheet 2, as shown in Figure 7-4.

The legume credit of 30 lb N/acre for the previous

soybean crop is shown on line 2.a, and the residual

sludge N credit is written on line 2.d. The total N credits

of 38 lb/acre are subtracted from the fertilizer N recommendation to get the adjusted N requirement. This remaining N requirement is then divided by the PAN calculated earlier in this section for the wheat field, i.e., 28

lb N/ton, to get an agronomic N sludge rate of 1.9 dry

ton/acre. This rate will be equivalent to:

1.9 dry ton

acre

×

100 wet ton (i.e., 4.8% solids )

4.8 dry ton ×

2,000 lb

wet ton × gallon

8.34 lb = 9,500 gallons⁄ acre

A separate Worksheet 2 can be used to calculate the

agronomic rate for the corn field, as shown in Figure 7-5.

The only N credit for this field is the residual sludge N

credit shown on line 2.d., which is subtracted from the

fertilizer N recommendation to get the adjusted N requirement (i.e., 163 lb N/acre). Dividing this requirement

by the PAN/ton calculated earlier for the corn field, i.e.,

35 lb N/ton, will obtain the agronomic N sludge rate of

4.7 dry ton/acre. This rate can be converted to a wet

weight basis, as was done for the wheat field, which is

equivalent to 23,500 gallons/acre. This amount of liquid

cannot be injected in a single application, so two applications of ~12,000 gal/acre each will be needed.

7.5.2 Calculation of Long-Term Pollutant

Loadings and Maximum Sewage

Sludge Quantities

By comparing the pollutant concentrations in this design

example to the Part 503 limits (see Chapter 3), the

reader will find that all trace element levels in the sewage sludge meet the “pollutant concentration limits” except copper. Therefore, CPLR limits must be met for this

sewage sludge. Utilizing the “maximum sewage sludge

allowed” equation from Section 7.4.4.3 and the CPLRs

from Table 7-9, the total quantity of sludge that could be

applied before exceeding the CPLR limit for each pollutant can be estimated:

Arsenic Max. sludge = 37 lb/acre 4

0.002 (8 mg/kg) = ~2,300 dry

ton/acre

Cadmium Max. sludge = 35 lb/acre 4

0.002 (10 mg/kg) = 1,750 dry

ton/acre

Chromium Pollutant limits will most likely be

deleted from Part 503 rule

Copper Max. sludge = 1,300 lb/acre 4

0.002 (1,700 mg/kg) = 382 dry

ton/acre

Lead Max. sludge = 270 lb/acre 4

0.002 (150 mg/kg) = 900 dry

ton/acre

83
Mercury Max. sludge = 15 lb/acre 4

0.002 (2 mg/kg) = 3,750 dry

ton/acre

Molybdenum Currently, no CPLR is required

for Mo.

Nickel Max. sludge = 380 lb/acre 4

0.002 (49 mg/kg) = ~3,900 dry

ton/acre

Selenium Max. sludge = 90 lb/acre 4

0.002 (15 mg/kg) = 3,000 dry

ton/acre

Zinc Max. sludge = 2,500 lb/acre 4

0.002 (1,200 mg/kg) = ~1,040 dry

ton/acre

Assuming this particular sewage sludge continued

to have the same concentrations over time, Cu would

continue to be the limiting pollutant. The pollutant loadings for each individual sewage sludge application

must be determined and recorded to keep a cumulative

summation of the total quantity of each pollutant that

has been added to each field receiving this sewage

sludge. To calculate the quantity of each pollutant

applied, the following equation from Section 7.4.4.3

can be used:

Sludge rate (dry ton/acre) x 0.002 (mg/kg pollutant) = lb pollutant/acre

For the two agronomic N rates calculated in Section

7.5.1, the amounts of each pollutant added by the sewage sludge are shown in Table 7-10.

These quantities would be added to the cumulative total

kept for each field receiving any sewage sludge that is

meeting CPLRs.

The approximate number of years that sewage sludge

(of the quality assumed in this design example) could be

applied before reaching the CPLR can be estimated. If

the pollutant concentrations remain the same and an

average, annual application rate is assumed, the maximum sludge quantity calculated above for the most

limiting pollutant (i.e., Cu) can be used to estimate the

number of years a site could be continuously utilized.

For this calculation, we will assume an average rate of

3.3 ton/acre/year, obtained by averaging the agronomic

N rates for the wheat field and the corn field [i.e., (1.9 +

4.7) 4 2]. Using the following equation, the number of

years can then be estimated:

Max. sludge allowed 4 average annual rate =

number of years:

382 dry ton/acre 4 3.3 dry ton/acre/year = ~116 years

Thus, these preliminary calculations indicate that Part

503 CPLR limits will likely not constrain the application

of sewage sludge if its quality was similar to that used

in this design example.

If the concentration of Cu was reduced until it met the

Part 503 pollutant concentration limits and all other pollutant concentrations remained constant, the CPLRs

would no longer have to be recorded to comply with the

503 regulation (see Chapter 3).

7.5.3 Calculation of Agronomic P Rate for

Each Field

The equation from Section 7.4.4.2 can be used to calculate the agronomic P rate for the wheat field and corn

field used in this design example. For the anaerobic

sewage sludge containing 1.9% total P, plant available

P2O5 can be estimated:

Total P2O5/dry ton = 1.9% x 20 x 2.3 =

87 lb P2O5/dry ton

Avail. P2O5/dry ton = 0.5 (87 lb total P2O5/dry ton) =

~44 lb P2O5/dry ton

For the wheat field, the agronomic P rate is calculated

as follows:

Table 7-10. Amounts of Pollutants Added by Sewage Sludge

in Design Example

Pollutant

Conc. in

Sludge

Wheat Field

(1.9 ton/acre)

Corn Field

(4.7 ton/acre)

mg/kg lb/acre

Arsenic 8 0.030 0.075

Cadmium 10 0.038 0.094

Chromiuma -- -

Copper 1,700 6.5 16 

Lead 150 0.57 1.4 

Mercury 2 0.0076 0.019

Molybdenuma - - -

Nickel 49 0.19 0.46 

Selenium 15 0.057 0.14 

Zinc 1,200 4.6 11 

a

 Limits for chromium will most likely be deleted from Part 503. Currently,

no calculation or recordkeeping for a CPLR is required for Mo.

84
Figure 7-3. Worksheet 1 calculations to determine residual N credits for previous sewage sludge applications.

85
Figure 7-4. Calculation of the agronomic N rate for the wheat field.

86
Figure 7-4. Calculation of the agronomic N rate for the wheat field (continued).

87
Figure 7-5. Calculation of the agronomic N rate for the corn field.

88
Figure 7-5. Calculation of the agronomic N rate for the corn field (continued).

89
Preq = Fertilizer P2O5 Recommendation =

80 lb P2O5/acre, so

Agronomic P rate = Preq 4 Avail. P2O5/dry ton =

80 lb P2O5/acre 4 44 lb P2O5/dry ton =

~1.8 dry ton/acre

For the corn field, the agronomic P rate would be:

Preq = 60 lb P2O5/acre, so

Agronomic P rate = 60 lb P2O5/acre 4

44 lb P2O5/dry ton = ~1.4 dry ton/acre

Since the agronomic P rate for each field is less

than the agronomic N rate, these rates could be selected to use. The consequence of utilizing P rates

rather than N rates is that less sewage sludge per acre

will normally be applied, so more land area will be

needed to apply the total sludge produced by the treatment works. For example, the design example treatment works generates 7,300 dry ton/year (i.e., 20 dry

ton/day x 365 days/year). If sludge was applied at a rate

equal to the agronomic P rate for the corn field, about

5,220 acres/year would be needed to apply all the

sludge produced (i.e., 7,300 dry ton/year 4 1.4 dry

ton/acre). But if sludge was applied at the agronomic N

rate for the corn field, only about 1,560 acres would be

needed to apply all the sludge produced (i.e., 7,300 dry

ton/year 4 4.7 dry ton/acre).

Alternatively, continuously using the agronomic N rate

would result in excess P (beyond what the crop needs)

being applied. As was discussed in Section 7.4.4.2, soil

P fertility levels will likely be increased over time. Unusually high soil P levels can potentially increase the risk of

nonpoint source pollution losses of P to surface waters

and contribute to undesirable water quality. A second

consequence is that supplemental N fertilizers must be

added to fulfill the remaining N needs of the crop not

supplied by the sewage sludge. The quantity of additional N can be calculated by returning to Worksheet 2

and multiplying the PAN/dry ton times the rate of sewage

sludge applied, and then subtracting this PAN/acre

value from the adjusted fertilizer N requirement.

For example, using Figure 7-5 for the corn field and

assuming the agronomic P rate was used (i.e., 1.4 dry

ton/acre), the supplemental N fertilizer needed is:

35 lb PAN/dry ton x 1.4 dry ton/acre =

49 lb PAN/acre

163 lb N/acre - 49 lb N/acre = 114 lb N/acre

7.5.4 Calculation of Supplemental K

Fertilizer To Meet Crop Nutrient

Requirements

Because K is a soluble nutrient, most of the K received

by a treatment works is discharged with effluents. Consequently, sewage sludges will contain low concentrations of this major plant nutrient. Therefore, fertilizer

potash (K2O) or other sources of K will be needed to

supplement the quantities of K2O added by sewage

sludge applications, particularly over the long-term.

The amount of sewage sludge K2O applied can be

calculated from sludge analysis information in a similar

manner as is done for P2O5 (Section 7.4.4.2). Since K

is readily soluble, however, all the K in sewage sludge

is assumed to be available for crop growth compared to

P, which is assumed to be about 50% available to plants.

As with P, soil fertility testing can be used to monitor

these K2O additions and determine additional K2O that

is needed for crops.

The quantity of K2O that can be credited against the K2O

fertilizer recommendation is calculated using the following equation:

Sludge K2O applied = Sludge rate (dry ton/acre) x

Avail. K2O/dry ton

where:

Avail. K2O = %K in sludge × 20 × 1.2*

*1.2 is the factor to convert lb K to lb K2O (the ratio of the atomic weights of K2O:K, i.e., 94:78).

For the wheat field, which had a K fertilizer recommendation of 125 lb K2O/acre, determining additional K2O

needs, assuming the agronomic N rate (i.e., 1.9 dry

ton/acre) is used, is as follows:

Since the sewage sludge for our design example

contains 0.5% K, the available K2O = 0.5% x

20 x 1.2 = 12 lb K2O/dry ton.

Sludge K2O applied = 1.9 dry ton/acre x

12 lb K2O/dry ton = 23 lb K2O/acre

Additional K2O needed = 125 lb K2O/acre -

23 lb K2O/acre = 102 lb K2O/acre

For the corn field, which had a fertilizer recommendation of

140 lb K2O/acre, and again assuming the agronomic N rate

(i.e., 4.7 dry ton/acre) is used, additional K2O needs will be:

Sludge K2O applied = 4.7 dry ton/acre x

12 lb K2O/dry ton = 56 lb K2O/acre

Additional K2O needed = 140 - 56 =

84 lb K2O/acre

90
7.5.5 Additional Considerations for Land

Application Program Planning

To simplify the design example, only two fields with different crops were considered. For most land application

programs, however, sewage sludge will be applied to more

than two crops and to many individual fields. Application

rate calculations should be made for each field receiving

sewage sludge as a detailed plan is developed. For this

design example, additional crops could be oats, soybeans,

and forages for hay and pasture. Crop rotations and

relative acreages of each crop will vary from one crop

producer to another. Also keep in mind that farms with

livestock will be producing animal manure nutrients in

addition to the sewage sludge nutrients used for supplying plant nutrient requirements on the acreage available for growing crops.

7.6 References

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Sewage sludge application in semiarid grasslands: Effects on

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Allaway, W. 1977. Soil and plant aspects of the cycling of chromium,

molybdenum, and selenium. Proc. Intern. Conf. Heavy Metals in

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Bartholomew, W.V. 1965. Mineralization and immobilization of nitrogen in the decomposition of plant and animal residues. In: W.V.

Bartholomew and F.E. Clark, eds. Soil Nitrogen Agronomy 10:285-

306. American Society of Agronomy, Madison, WI.

Beasley, B., W. Knisel, and A. Rice, eds. 1991. Proceedings of the

CREAMS/GLEAMS Symposium. Publication No. 4. Agricultural

Engineering Department, University of Georgia, Athens, GA.

Beauchamp, E.G., G.E. Kidd, and G. Thurtell. 1982. Ammonia volatilization from sewage sludge applied in the field. Can. J. Soil Sci.

62:11-19.

Beauchamp, E.G., G.E. Kidd, and G. Thurtell. 1978. Ammonia volatilization from sewage sludge applied in the field. J. Environ. Qual.

7:141-146.

Berglund, S., R.D. Davis, and P. L’Hermite. 1984. Utilization of sewage sludge on land: Rates of application and long-term effects of

metals. D. Reidel Publishing Company, Dordrecht, Holland. p.

229.

Brunke, R., P. Alvo, P. Schuepp, and R. Gordon. 1988. Effect of

meteorological parameters on ammonia loss from manure in the

field. J. Environ. Qual. 17:431-436.

Burkhardt, J., W. Miller, and M. Azad. 1993. Biosolids application to

rangelands. Water Environ. and Tech. 5(5):68-71.

CAST. 1980. Effects of sewage sludge on the cadmium and zinc

content of crops. Report No. 83. Council for Agricultural Science

and Technology, Ames, IA. p. 77

CAST. 1976. Application of sewage sludge to cropland: Appraisal of

potential hazards of the heavy metals to plants and animals. Report No. 64. Council for Agricultural Science and Technology,

Ames, IA. p. 63.

Chaney, R.L. 1984. Potential effects of sludge-born heavy metals and

toxic organics on soils, plants, and animals, and related regulatory

guidelines. In: Workshop on the International Transportation, and

Utilization or Disposal of Sewage Sludge, Including Recommendations (December 12-15). Final Report PNSP/85-01. Pan American Health Organization, Washington, DC. p. 56.

Chaney, R.L. 1983a. Plant uptake of inorganic waste constituents. In:

J.F. Parr, P.B. Marsh, and J.M. Kla, eds. Land treatment of hazardous wastes. Noyes Data Corporation, Park Ridge, NJ. p. 50-

76.

Chaney, R.L. 1983b. Potential effects of waste constituents on the

food chain. In: J.F. Parr, P.B. Marsh, and J.M. Kla, eds. Land

treatment of hazardous wastes. Noyes Data Corporation, Park

Ridge, NJ. p. 152-240.

Chaney, R.L. 1973. Crop and food chain effects of toxic elements in

sludges and effluents. In: Proceedings of Joint Conference on

Recycling Municipal Sludges and Effluents on Land, Champaign,

IL (July 9-13). National Association of State Universities and LandGrant Colleges, Washington, DC. p. 129-141.

Chaney, R.L., and P.M. Giordano. 1977. Microelements as related to

plant deficiencies and toxicities. In: Elliott, L.F., and F.J. Stevenson,

eds. Soils for management of organic wastes and waste waters.

American Society of Agronomy, Madison, WI. p. 235-279.

Christensen, B.T. 1986. Ammonia volatilization loss from surface applied animal manure. In: Dam Kofoed, A., J.H. Williams, and P.

L’Hermite, eds. Efficient land use of sludge and manure. London:

England: Science Publishers Ltd. pp. 193-203.

Davis, R.D., G. Hucker, and P. L’Hermite. 1983. Environmental effects

of organic and inorganic contaminants in sewage sludge. Dordrecht, Holland: D. Reidel Publishing Company. p. 257

Davis, F., W. Knisel, and R. Leonard. 1990. GLEAMS user manual,

Version 1.8.55. Lab. Note SEWRL-030290FMD. Agricultural Research Service, U.S. Department of Agriculture, Tifton, GA.

Döhler, H., and M. Wiechmann. 1988. Ammonia volatilization from

liquid manure after application in the field. In: Welte, E., and I.

Szabolcs, eds. Agricultural waste management and environmental

protection, Vol. 2. Groltze-Druck, Goettingen, Federal Republic of

Germany. pp. 305-313.

Follet, R., D. Keeney, and R. Cruse, eds. 1991. Managing nitrogen for

groundwater quality and farm profitability. Soil Science Society of

America, Madison, WI. p. 357.

91
Fresquez, P., R. Aguilar, R. Francis, and E. Aldon. 1991. Heavy metal

uptake by blue grama growing in a degraded semiarid soil

amended with sewage sludge. The Netherlands: Kluwer Academic

Publishers.

Fresquez, P., R. Francis, and G. Dennis. 1990. Soil and vegetation

responses to sewage sludge on a degraded semiarid broom

snakeweed/blue grama plant community. J. Range Mgmt.

43(4):325-331.

Gallier, W., B. Brobst, R. Aguilar, K. Barbarick, P. Hegeman, B. Janonis, D. Salahub, and S. Wilson. 1993. Rx for rangelands. Water

Environ. and Tech. 5:10.

Gilmour, J., and M. Clark. 1988. Nitrogen release from wastewater

sludge: A site specific approach. J. Water Pollut. Control Fed.

60:494-341.

Hall, J.E., and J.C. Ryden. 1986. Current UK research into ammonia

losses from sludges and slurries. In: Dam Kofoed, A., J.H. Williams, and P. L’Hermite, eds. Efficient land use of sludge and

manure. London, England: Science Publishers Ltd. pp. 180-192.

Harmsen, G.W., and D.A. Van Schreven. 1955. Mineralization of organic

nitrogen in soil. Adv. Agron. 7:299-398.

Hoff, J.D., D.W. Nelson, and A.L. Sutton. 1981. Ammonia volatilization

from liquid swine manure applied to cropland. J. Environ. Quality

10:90-95.

Ippolito, J., K. Barbarick, D. Westfall, R. Follett, and R. Jepson. 1992.

Application of anaerobically digested sewage sludge to dryland

winter wheat. Technical Report TR92-5. Agricultural Experiment

Station, Colorado State University.

Jacobs, L., S. Carr, S. Böhm, and J. Stukenberg. 1993. Document

long-term experience of biosolids land application programs. Project 91-ISP-4. Water Environment Research Foundation. Alexandria, VA.

Keeney, D.R. 1989. Sources of nitrate to groundwater. In: R.F. Follett,

ed. Nitrogen management and ground water protection. Amsterdam, the Netherlands: Elsevier Science Publishers. pp. 23-34.

Knisel, W., ed. 1980. CREAMS: A field-scale model for chemicals, runoff,

and erosion from agricultural management systems. Conservation

Research Report No. 26. U.S. Department of Agriculture, Washington, DC. p. 643.

Lauer, D.A., D.R. Bouldin, and S.D. Klausner. 1976. Ammonia volatilization from dairy manure spread on the soil surface. J. Environ.

Quality 5:134-141.

L’Hermite, P., and J. Dehandtschutter. 1981. Copper in animal wastes

and sewage sludge. Dordrecht, Holland: D. Reidel Publishing

Company. p. 378.

Lindsay, W.L. 1973. Inorganic reactions of sewage wastes with soils.

In: Proceedings of Joint Conference on Recycling Municipal

Sludges and Effluents on Land, Champaign, IL (July 9-13). National Asssociation of State Universities and Land-Grant Colleges,

Washington, DC. pp. 91-96.

Logan, T.J., and R.L. Chaney. 1983. Utilization of municipal wastewater and sludge on land -metals. In: Page, A.L., T.L. Gleason,

III, J.E. Smith, Jr., I.K. Iskandar, and L.E. Sommers, eds. Utilization

of municipal wastewater and sludge on land. University of California, Riverside, CA. pp. 235-326.

Melsted, S.W. 1973. Soil-plant relationships (some practical considerations in waste management). In: Proceedings of Joint Conference on Recycling Municipal Sludges and Effluents on Land,

Champaign, IL (July 9-13). National Asssociation of State Universities and Land-Grant Colleges, Washington, DC. pp. 121-128.

Page, A.L., T.J. Logan, and J.A. Ryan, eds. 1987. Land application

of sludge—food chain implications. Chelsea, MI: Lewis Publishers,

Inc. p. 168.

Peterson, R., and M. Madison. 1992. Benefits of transporting biosolids

from a wet climate to a dry climate. Presented at Water Environment Federation Specialty Conference, July 26-30.

Pierce, B., E. Redente, and K. Barbarick. 1992. Review of sewage

sludge-amended rangeland at Walcott, Colorado. Progress Report

to Colorado Department of Health and U.S. EPA. Colorado State

University, Fort Collins, CO.

Pierce, B. 1994. The effect of biosolids application on a semiarid

rangeland site in Colorado. M.S. Thesis, Colorado State University, Fort Collins, CO.

Powers, W.L., G.W. Wallingford, and L.S. Murphy. 1975. Formulas for

applying organic wastes to land. J. Soil Water Conserv. 30:286-

289.

Pratt, P.F., F.E. Broadbent, and J.P. Martin. 1973. Using organic

wastes as nitrogen fertilizers. California Agriculture 27(6):10-13.

Rank, M., J. Huber, and A. Amberger. 1988. Model trials on the volatilization of ammonia following slurry application under controlled climate and field conditions. In: Welte, E., and I. Szabolcs, eds.

Agricultural waste management and environmental protection, Vol.

2. Groltze-Druck, Goettingen, Federal Republic of Germany. pp.

315-320.

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Colorado. Prepared by RDB, Inc., and Camp, Dresser & McKee

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waste management and treatment. New York, NY: McGraw Hill

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under the Clean Water Act Section 503: a model for exposure and

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of Composting. Worthington, OH: Renaissance Publications,

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water protection. Amsterdam, the Netherlands: Elsevier Science

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93
Chapter 8

Process Design for Forest Land Application Sites

8.1 General

Sewage sludge application to forests can greatly increase forest productivity. Research at the University of

Washington showed that for some tree species, the use

of sewage sludge as a fertilizer resulted in excellent and

prolonged increases in height and diameter growth compared to controls (Henry et al., 1993). Sewage sludge

amends the soil by providing nutrients, especially nitrogen (N) and phosphorus (P), that are frequently limited

in forest soils, and by improving soil textural characteristics. Sewage sludge addition can improve shortterm soil productivity because it provides an immediate

supply of virtually every nutrient needed for plant growth

in an available form. In addition, the fine particles and

organics in sewage sludge can immediately and permanently enhance soil moisture and nutrient-holding characteristics. In the long-term, sewage sludge provides a

continual slow release input of nutrients as the organics

decompose.

Forest soils are in many ways well suited to sewage

sludge application. They have high rates of infiltration

(which reduce runoff and ponding), large amounts of

organic material (which immobilize metals from the sewage sludge), and perennial root systems (which allow

year-round application in mild climates). Although forest

soils are frequently quite acidic, research has found no

problems with metal leaching following sewage sludge

application (U.S. EPA, 1984).

One major advantage of forest application over agricultural application is that forest products (e.g., wild edible

berries, mushrooms, game, and nuts) are an insignificant part of the human food chain. In addition, in many

regions, forest land is extensive and provides a reasonable sewage sludge land application alternative to agricultural cropland. The primary environmental and public

health concern associated with forest application is pollution of water supplies. In many areas, particularly in

the western states, forest lands form crucial watersheds

and ground-water recharge areas. Contamination of

water supplies by nitrates can be prevented by limiting

sewage sludge application rates according to the nitrogen needs of the crop (as required by the Part 503

regulation), in this case trees (approximately 10 to 100

metric tons dry weight per hectare [t DW/ha] in a single

application every 3 to 5 years).

Application of sewage sludge to forest land is feasible

on commercial timber and fiber production lands, federal

and state forests, and privately owned woodlots. Sewage sludge use in nurseries, green belt management,

and Christmas tree production also is possible.

This chapter discusses sewage sludge applications to

forest land for three common situations: (1) recently

cleared forest land that has not been planted, (2) young

plantations (planted or coppice), and (3) established

forest stands. Each of these cases presents different

design issues and opportunities. Public participation

considerations are a critical aspect of forest land application systems, as discussed in Chapter 12.

8.2 Regulatory Requirements and Other

Considerations

The federal Part 503 regulatory requirements associated with land application of sewage sludge to forest

lands regarding metals, pathogens, and nitrogen are

discussed in Chapter 3. Issues particularly relevant to

land application at forest sites are discussed below.

8.2.1 Pathogens

Organisms present in forest soils are responsible for the

relatively quick die off of pathogens following sewage

sludge application to a forest site. Microorganisms present in the sewage sludge are initially filtered out by the

soil and forest floor and then replaced by the native

organisms of the soil. The survival time for most microorganisms following land application of sewage sludge

to forests typically is very short but depends on a variety

of soil and climatic conditions including temperature,

moisture content, and pH.1

 For a further discussion of

pathogen die off, see Chapter 4.

Pathogen-related concerns involving windborne contamination may arise when spray application of liquid

1

 Henry, Charles. Biosolids Utilization in Forest Lands. Draft report.

University of Washington, Eatonville, WA.

95
sewage sludge on forest lands is used. Precautions can

be taken to minimize exposure during and after spray

application, such as restricting public access from the

area downwind during the spray application and for

several hours after spraying is completed, and considering wind velocity so that applications can be controlled. Generally, aerosols will not travel far in an

established, non-dormant forest because of interception

by the leaves and breakup of wind currents.

8.2.2 Nitrogen Dynamics

As with other types of land application sites, nitrogen

needs at forest sites (i.e., N needed by trees and understory) are an essential component of the land application

system. Sewage sludge at a forest site must be applied

at a rate that is equal to or less than the agronomic rate

for N, as required by the Part 503 regulation. Key factors

regarding nitrogen levels at forest sites include nitrogen

uptake by plants; mineralization of nitrogen; ammonia

volatilization; denitrification; soil immobilization rates; nitrogen leaching; and temperature-related effects. These

factors are discussed in Section 8.9 below, particularly

as they affect determination of sewage sludge application rates at forest sites.

8.3 Effect of Sewage Sludge

Applications on Tree Growth and

Wood Properties

8.3.1 Seedling Survival

Seedlings of deciduous species and many conifers, including Douglas fir and Sitka spruce, have shown excellent tolerance to sewage sludge in demonstration

projects. At relatively light application rates (i.e. agronomic loadings), seedling mortality is not a problem, and

planting should be possible soon after sludge application.

8.3.2 Growth Response

Growth response has been documented on a number of

stands of Douglas-fir in Washington (Henry et al., 1993).

Growth responses can range from 2% to 100% for

existing stands, and over 1,000% for trees planted in

soils amended with heavy applications of sewage

sludge. The magnitude of this response depends on site

characteristics and tree stand ages. Some of the main

site differences affecting growth response include:

• Site class. In both young Douglas-fir plantations and

older stands, greater growth responses have been

found where the trees are doing poorly due to lack

of nutrients.

• Thinned versus unthinned stands treated with sewage sludge. There appears to be little difference in

total wood produced in unthinned versus thinned stands

that have received sewage sludge applications. In thinned

stands, however, growth is concentrated in trees with

larger diameters.

• Response by species. Most tree species grow faster

in soil treated with sewage sludge; however, some

species respond dramatically while others show only

a slight response. Excellent response has been

shown by black locust, European alder, hybrid poplar,

Japanese larch, and catalpa (Sopper, 1993).

Greater growth responses have been seen when trees

have been planted directly in soil already amended with

large amounts of sewage sludge, such as a soil reclamation site. In this case, special management practices

are required. An excellent example of this type of application is Christmas tree plantations.

Because sewage sludge application to forest sites is

relatively new and limited data have been collected, it is

difficult to estimate the value added to a forest site when

sewage sludge is land applied. A conservative estimate

of the value of sewage sludge could be based on the

value of the nitrogen fertilizer potential alone, which

would be approximately $30/dry ton of sewage sludge.

Preliminary studies, however, have shown a greater

growth response to sewage sludge than to chemical

nitrogen fertilizer. Additionally, the effect appears to be

much longer lasting, with some studies showing continued growth response 8 years after application.

8.3.3 Wood Quality

Accelerated tree growth (200 to 300 percent) resulting

from sewage sludge addition has the potential for

changing basic wood characteristics, including specific

gravity, shrinkage, fibril angle, and certain mechanical

properties. Research indicates that both positive and

negative effects on wood quality occur in trees grown on

sewage sludge-amended soil. In some studies, static

bending tests, which show combined effects, have indicated no significant change when the strength properties of specimens cut from trees grown on sewage

sludge-amended soils were compared with specimens

of wood produced without sewage sludge. Other studies

have shown a 10 to 15 percent reduction in density and

in modulus of rupture and elasticity.2

8.4 Effect of Sewage Sludge Application

on Forest Ecosystems

Although immediately after land application of sewage

sludge a site is greatly altered in appearance, within six

months understory growth often is much more vigorous

than before sewage sludge application. Increased understory also is typically higher in nutrients and can

provide better habitat for wildlife. A number of wildlife

studies have found increased populations of animals on

2

 See footnote 1.

96
sites receiving sewage sludge compared to nearby sites

that were not amended with sewage sludge (Henry and

Harrison, 1991).

8.5 Forest Application Opportunities

8.5.1 Forest Stand Types

The land application designer may have the option of

selecting among the following types of forest sites for

sewage sludge addition:

• Sites recently cleared prior to replanting.

• Young plantations of an age conducive to sewage

sludge application over the tops of trees.

• Established forests.

The advantages and disadvantages associated with each

type of forest site are summarized in Tables 8-1 to 8-3.

8.5.1.1 Applications Prior to Planting

Clearcuts offer the easiest, most economical sites for

sewage sludge application. Because application takes

place prior to tree planting, many agricultural sewage

sludge application methods can be used. Vehicles delivering sewage sludge from the treatment plant can

discharge semi-solid sewage sludge (15% or more solids) directly on the land, followed by spreading by a

dozer and disking. Ease of delivery depends on the

amount of site preparation (stump removal, residual

debris burning, etc.), slopes, soil conditions, and

weather. Site preparation and sewage sludge characteristics are also major factors in application technique

(e.g., temporary spray irrigation systems; injectors and

splash plates for liquid material; manure spreaders for

solid material).

While sewage sludge application is easier to perform on

clearcuts, these sites also may require additional management practices to control grasses and rodents such

as voles. If application to a clearcut is planned, a program of periodic disking and herbicides should be conducted to control grasses and rodents. Tree trunk

protection devices also are available to provide a barrier

against rodent girdling. Additionally, fencing or bud capping may be required to prevent excessive deer browsing. Sewage sludge injection into the soil may minimize

plantation establishment problems.

8.5.1.2 Applications to Young Stands

Application of sewage sludge to existing stands typically

is made by a tanker/sprayer system, which can apply

sewage sludge with an 18% solids content over the tops

of the trees (canopy) 125 feet (40 m) into a plantation.

This method requires application trails at a maximum of

250 feet (80 m) intervals. King County Metro, Washington (including Seattle), has developed a throw spreader

that is capable of applying a dewatered sewage sludge

up to 70 m over a plantation. This method has greatly

reduced application costs and allows trail spacing of

greater distances (120 m with overlap for evenness of

applications). A good tree age or size for this type of

application are trees over 5 years or over 4 to 5 feet high

because they minimize maintenance otherwise needed

in clearcut areas. Timing of applications may be important with over-the-canopy applications because sewage

sludge sticking on new foliage could retard the current

year’s growth during the active growth season.

Table 8-1. Sewage Sludge Application to Recently Cleared Forest Sites

Advantages

1. Better access for sludge application equipment. Also, optimal access can be established for additional sludge application in the

future.

2. Possible option of incorporating the sludge into the soil (versus a surface application) if the site is sufficiently cleared.

3. Possible option of establishing a flooding or ridge and furrow sludge application system (versus spray application) if the site

topography is favorable.

4. Option to select tree species that show good growth and survival characteristics on sludge-amended sites.

5. Often easier to control public access to the site because cleared areas are less attractive than wooded areas for typical forest

recreational activities.

Disadvantages

1. Seedlings have low nitrogen uptake rates. If nitrate contamination of an underlying potable aquifer is a potential problem, initial

sludge applications must be small relative to the volume of sludge application to established forests.

2. An intensive program of weed control is necessary since the weeds grow faster than the seedlings and compete for nutrients,

space, light, etc. Use of herbicides and cultivation between tree rows usually is required for the first 3 to 4 years.

3. Intensive browsing by deer and damage to young trees by voles and other pest species may require special control measures,

since these animals may selectively feed upon trees grown on sludge-amended sites due to their higher food value.

97
Liquid sewage sludge also has been successfully applied

using a sprinkler irrigation system. Clogging of nozzles has

been the major drawback to this method. Manure spreaders are capable of applying dewatered sewage sludge

which cannot be sprayed. Depending on the range of

sewage sludge trajectory, application trails may need to be

at closer intervals than with other methods.

It is recommended that sewage sludge applications take

place during the time that tree growth is reduced, but

uptake of nutrients also is reduced during this time.

When sewage sludge is first applied to the soil, the

available N is in the NH4

+

 form, which does not leach. In

addition, in some cases such as in northern cool climates, during the non-growing season soil temperatures are low and neither N mineralization (transformation of organic N to NH4

+

) or nitrification (transformation

of NH4

+

 to NO3

−

) occurs significantly. Thus nutrients are

effectively “stored” until the next growing season.

8.5.1.3 Applications to Mature Stands

Applications to older stands have the advantage that

sewage sludge can be applied year-round. Because

spraying takes place under the tree foliage, no foliage

will be affected. Application methods are similar to those

described for young plantations. In many cases, however, stands are not in rows, which may eliminate some

of the alternatives available for plantations.

Table 8-2. Sewage Sludge Application to Young Forest Plantations (Over 2 Years Old)

Advantages

1. Seedlings are established and more tolerant of fresh sludge applications.

2. Weed control is less of a problem than with cleared sites because of established trees and vegetation.

3. Nitrogen uptake by the trees is rapidly increasing, and acceptable sludge application rates can be higher on these sites over

aquifers than on recently cleared sites.

4. Access for sludge application equipment usually is still good.

5. Rapid growth response from most deciduous and many coniferous tree seedlings can be expected.

Disadvantages

1. Sludge application by spraying over the canopy may be restricted to those periods when the trees are dormant, to avoid the

problem of sludge clinging to foliage. Application during periods of the year when heavy rainfalls are common may potentially

alleviate this problem. In addition, sewage sludge applied to broad leaf species quickly dries and flakes off the leaves.

2. Some weed control will probably be necessary.

Table 8-3. Sewage Sludge Application to Closed Established Forest (Over 10 Years Old)

Advantages

1. Established forests are less susceptible to sludge-induced changes in vegetation (e.g., weed growth).

2. Excellent growth response can be expected to result from the increased nutrients.

3. Sludge application by spraying can be done under the tree foliage, so it is not necessary for the trees to be dormant.

4. During precipitation, rapid runoff of storm water containing sludge constituents is unlikely because the forest canopy breaks up the

rain and accumulated organic debris on the forest floor absorbs runoff.

5. Forest soils under established forests usually have high C-to-N ratios resulting in excellent capability to immobilize (store)

nitrogen for slow release in future years. Consequently, it often is feasible to make an initial heavy application of sludge, e.g.,

74 t/ha (33 T/ac), and achieve tree growth response for up to 5 years without subsequent sludge applications.

Disadvantages

1. Access by sludge application vehicles into a mature forest often is difficult. The maximum range of sludge spray cannons is about

40 m (120 ft). To obtain fairly uniform coverage, the spray application vehicle requires access into the site on a road grid, spaced

at approximately 75-m (250-ft) intervals. Most established forest sites do not have such grid-like roads. As a result, access roads

must be cut through the forest, or the selected sludge application area(s) are largely restricted to narrow 36-m (120-ft) strips on

both sides of existing roads. Access into commercial forests is usually easier than into publicly owned forest lands.

2. In an established publicly owned forest, it may not be advantageous to accelerate vegetation with sludge applications. In contrast,

commercial forest operations desire faster growth of trees.

Notes:

t = metric tonnes

T = English tons (short)

98
8.5.2 Christmas Tree Plantations

One clearcut application scenario that has worked well

in the state of Washington is the use of sewage sludge

application in Christmas tree stands. Typically, a high

level of maintenance is common, and weed establishment and rodent populations are minimized as

standard practice.

8.6 Equipment for Sewage Sludge

Application at Forest Sites

8.6.1 Transfer Equipment

Sewage sludge usually comes from the wastewater

treatment plant (WWTP) in an over-the-road vehicle.

Once at the site it is often stored, at least temporarily,

before being transferred to an application vehicle. Exceptions to storage are when a multi-purpose highway/application vehicle is used (generally by smaller

facilities) and when applications are close to the WWTP.

The two basic mechanisms for transferring sewage

sludge from vehicles to storage facilities are (1) direct

dumping, and (2) pumping. The transfer method suitable

for a particular site depends on how liquid the sewage

sludge is (i.e., how easy it is to pump), or the position

and configuration of the storage vessel (i.e., whether

gravity is sufficient to transfer the sewage sludge).

Direct dumping of sewage sludge is the easiest method

for unloading a trailer from a treatment plant. Gravity

dumping requires either using an in-ground storage facility or driving the truck onto a ramp above the storage

facility. Additionally, sewage sludge must be dilute

enough to flow from the trailer (<8% solids) or pressurized tank (<15% solids), or the trailer bed must be tilted.

Pumping the sewage sludge can work if the sewage

sludge is liquid enough. Below 10% to 15% solids, most

sewage sludge flows as a semi-solid and can be fed through

a pump. Higher solids concentrations restrict or eliminate the

flow of sewage sludge to the pump. Centrifugal pumps can

be used for dilute sewage sludge (<10% to 13% solids),

or chopper-type centrifugal pumps may be able to pump

sewage sludge of up to 15% solids. If dewatered sewage

sludge (>15%) is brought to the site and a pump is to be

used to transfer the sludge, water must be added and

mixed with the sewage sludge before pumping is possible.

8.6.2 Application Equipment

There are four general types of methods for applying

sewage sludge to forests: (1) direct spreading; (2) spray

irrigation with either a set system or a traveling gun; (3)

spray application by an application vehicle with a spray

cannon; and (4) application by a manure-type spreader.

The main criteria used in choosing a system is the liquid

content of the sewage sludge. Methods 1, 2, and 3 are

effective for liquid sewage sludge (2% to 8% solids);

Methods 1 and 2 can be used for semi-solid sewage

sludge (8% to 18% solids); and only Method 4 is acceptable for solid sewage sludge (20% to 40% solids). Table

8-4 lists these methods, their range of application, relative costs, and advantages and disadvantages. The

method used by most municipalities for forest applications is spray application by an application vehicle with

a mounted cannon, although King County Metro in

Washington state now applies a dewatered sewage

sludge with a throw spreader.

Many application vehicles have been developed for use in

agricultural applications. Most of these can be readily

modified for forest use by mounting a spray nozzle and

pump on the tank. Application vehicles can also be custom

made. Depending on the site needs, a specially designed

all-terrain vehicle can be used. In some cases, a used

heavy-duty truck chassis with a rear-mounted tank has

been modified for forest use. The application vehicle can

either be filled by a traveling tanker, directly from on-site

storage, or can itself be an over-the-road multi-purpose

(transport/application) vehicle. Once full, the application

vehicle moves into the forest over the roads or trails and

Table 8-4. Comparison of Different Application Systems for Forest Sites (Henry, 1991)

System and Range Relative Costs Advantages Disadvantages

Sludge spreading and

incorporation range = 10’ (3 m)

Low capital and O&M Simple to operate; any %

solids

Need cleared site; difficult plantation

establishment with some species

Spray irrigation:

Set irrigation systems

range = 30’ - 200’

Traveling big gun

range = 200’

High capital, low O&M

Moderate capital, low

O&M

Simple to operate

Simple to operate on

appropriate sites

Frequent clogging; use only low %

solids; brush interferes

Frequent clogging; use only low %

solids; brush interferes

Application vehicle with

mounted cannon range = 125’

Low-moderate capital,

high O&M

Any terrain; sludge up to

18% solids

May need special trails

Manure-type spreader

range = 50’-200’

Low capital and O&M Only effective way to apply

high % solids sludge

Limited to high % solids; trails may

need to be close together

O&M = operation and maintenance costs.

99
unloads the sewage sludge in uniform thin layers while

the vehicle is either moving or stationary.

Considerations for on-site storage are discussed in

Chapter 14.

8.7 Scheduling

Sewage sludge applications to forest sites can be made

either annually or once every several years. Annual

applications are designed to provide N only for the

annual uptake requirements of the trees, considering

volatilization and denitrification losses and mineralization from current and prior years. An application one

year followed by a number of years when no applications are made utilizes soil storage (immobilization) of

nitrogen to temporarily tie up excess nitrogen that will

become available in later years.

In a multiple-year (e.g., every 3 to 5 years) application

system, the forest floor, vegetation, and soil have a

prolonged period to return to normal conditions, and the

public can use the site for recreation in the non-applied

years. Application rates, however, are not simply an

annual rate multiplied by the number of years before

reapplication, but rather need to be calculated so that

no NO3

−

 leaching occurs. If the sewage sludge is quite

liquid (<5% solids), annual applications may be preferred, since the water included with heavier applications

at low percent solids may exceed the soil’s infiltration rate.

In this case surface sealing may occur, increasing the

potential for runoff as well as anaerobic conditions, which

can cause odor problems or stress the plants.

For liquid and semi-liquid sewage sludge, if the total

depth of an application is to be greater than approximately one-quarter of an inch, it is recommended that a

series of three or more partial applications (with the

number depending on the percent solids of the sludge)

be made rather than one heavy application. This practice allows more even applications to be made, provides

time for stabilization or drying of the sewage sludge to

occur, and is important for maintaining infiltration and controlling runoff. The “rest” between applications will range

from 2 to 14 days depending on weather conditions.

Scheduling sewage sludge application also requires a

consideration of climatic conditions and the age of the

forest. High rainfall periods and/or freezing conditions

can limit sewage sludge applications in almost all situations. The Part 503 regulation prohibits bulk sewage

sludge from being applied to forest land that is flooded,

frozen, or snow-covered so that the sewage sludge

enters a wetlands or other surface waters. In addition,

vehicle access to steeper soils could potentially be too

difficult during the wet parts of the year. As discussed in

Section 8.5.1.2, all applications to young plantations

should be done when the trees are dormant (e.g., during

the late fall, winter, and early spring).

An application schedule for a 1-year period is shown in

Table 8-5 for a design in the Pacific Northwest. Using

such a schedule, it would be feasible to avoid the need

for storage, especially when alternative management

schemes are available. On-site storage, however, may

also be desirable.

8.8 Determining Sewage Sludge

Application Rates for Forest Sites

8.8.1 General

As with agricultural lands, sewage sludge application

rates at forest sites usually are based on tree N requirements. As discussed below, nitrogen dynamics of forest

systems are somewhat more complex than agricultural

systems because of recycling of nutrients in decaying

litterfall, twigs and branches, and the immobilization of

the NH4

+

 contained in sludge as a result of decomposition

of these materials. As with agricultural applications, concentrations of trace elements (metals) in some sewage

sludges may limit the cumulative amount of sewage

sludge that can be placed on a particular area (see

Chapter 7, Section 7.4.4.3).

8.8.2 Nitrogen Uptake and Dynamics in

Forests

In general, uptake and storage of nutrients by forests

can be as large as that of agricultural crops if the system

is correctly managed and species are selected that

Table 8-5. Monthly Application Schedule for a Design in the

Pacific Northwest

Glacial Soil Residual Soil

Month

Young

Plantation

Established

Forest

Young

Plantation

Established

Forest

January Aa A LA LA

February A A LA LA

March A A LA LA

April NA A NA A

May NA A NA A

June NA A NA A

July NA A NA A

August NA A NA A

September NA A NA A

October A A LA LA

November A A LA LA

December A A LA LA

a

 Abbreviations:

 A = Site available, no limitations.

 NA = Not available, damage will be caused by sludge on growing

foliage.

 LA = Limited availablity, periods of extended rain are to be

avoided due to vehicle access problems

100
respond to sewage sludge. The trees and understory

utilize the available N from sewage sludge, resulting in

an increase in growth. There is a significant difference

between tree species in their uptake of available N. In

addition, there is a large difference between the N uptake by seedlings, vigorously growing trees, and mature

trees. (One study found that in young Douglas-fir, uptake

can be up to 100 lb-N/ac/yr when the trees fully occupy

the site, but as low as 25 lb-N/ac/yr in old Douglas-fir

stands [Dyck et al., 1984]). Finally, the amount of vegetative understory on the forest floor will affect the uptake

of N; dense understory vegetation markedly increases

N uptake.

Table 8-6 provides estimates of annual N uptake by the

overstory and understory vegetation of fully established

and vigorously growing forest ecosystems in selected regions of the United States. The reported average annual

N uptakes vary from 106 to 300 kg/ha/year (89 to 267

lb/ac/year), depending on species, age, etc. Note that all

of the trees listed in the table are at least 5 years old, and

that during initial stages of growth, tree seedlings will have

relatively lower N uptake rates than shown.

Calculation of sewage sludge application rates to supply

plant N requirements is somewhat more complicated

than for agricultural crops because the following nitrogen transformations need to be considered in addition

to N mineralization and ammonia volatilization from the

sewage sludge: (1) denitrification, (2) uptake by understory, and (3) soil immobilization for enhancement of

forest soil organic-N (ON) pools. Table 8-7 presents

ranges of values and suggested design values for nitrogen transformations and losses from sewage sludge

applied to forest environments. The discussion below

focuses on major aspects of nitrogen dynamics in forest

ecosystems.

8.8.2.1 Nitrogen Mineralization

Mineralization (transformation of organic N to NH4

+

) occurs when the organics in sewage sludge decompose,

releasing NH4

+

. Typical values for N mineralization for the

first year can be quite variable, ranging from 10% to

50% or more. A recent study conducted on a number of

sewage sludges from Oregon found that N mineralization

Table 8-6. Estimated Annual Nitrogen Removal 

by Forest Types

Tree Age Average N Uptake

Forest Type (years) (lb/ac/yr) (kg/ha/yr)

Eastern Forests 

(Irrigated Wastewater)

Mixed Hardwoods 40-60 200

Red Pine 25 100

Old Field with White

Spruce Plantation

 15 200

Pioneer Succession 5-15 200

Aspen Sprouts - 100

Southern Forests 

(Irrigated Wastewater)

Mixed Hardwoods 40-60 280

Southern Pine with No

Understory 

(mainly Loblolly)

 20 200

Southern Pine with

Understory 

(mainly Loblolly)

 20 260

Lake States Forests 

(Irrigated Wastewater)

Mixed Hardwoods 50 100

Hybrid Poplara 20 150

Western Forests

Irrigated Wastewater

Hybrid Poplar

Douglas Fir Plantation

 4-5

 15-25

300

200

Sludge Application

Hybrid cottonwood

Young Douglas-fir, 100%

site occupied

Older Douglas-fir

Understory, first

applicationb

Understory, reapplications

 5

 7-15

 >40

 -

 -

250

100

 45

100

 0

Sources: Stone (1968) for irrigated wastewater sites; Henry (see

footnote 1) for western sludge application. a

 Short-term rotation with harvesting at 4 to 5 years; represents first

growth cycle from planted seedlings. b

 Adjust by % site covered.

Table 8-7. Ranges of Values and Suggested Design Values

for Nitrogen Transformations and Losses From

Sewage Sludge Applied to Forest Environments

(Henry, 1993)

Transformation/Loss Design Value Range Suggested

Nitrogen Mineralization

Anaerobically digested

short detention

long detention

20% - 65%

40%

20%

Lagooned

short detention

long detention

10% - 20%

20%

10%

Composted

mixed or with short detention

long detention, fully cured

5% - 50%

40%

10%

Ammonia Volatilization 0% - 25%

Open stand

Closed stand

10%

 0%

Denitrification

Moist soils much of year

Dry soils

10%

 0%

Soil Immobilization 0 - 1,000 lb/ac

First application

young stand

old stand 

100 lb/ac

0 lb/ac

Reapplications 0 lb/ac

Plant Uptake (see Table 8-6)

101
ranged from 20% to 65% for anaerobically digested

sewage sludge, 15% to 19% for lagooned sewage

sludge, and 36% to 50% for short-detention composted

sewage sludge for the first year.3

 Table 8-7 gives ranges

and typical values for mineralization of sewage sludge

applied to forest sites. Because mineralization of different sewage sludge varies so much, it is recommended

that mineralization studies be conducted on specific

sewage sludge.

8.8.2.2 Ammonia Volatilization

Volatilization losses (when NH4

+

 escapes to the atmosphere) from sewage sludge surface-applied to agricultural soils have been measured from 10% to 60% of the

initial NH4

+

, and a typical design number is 50%. Forest

environments, however, probably lose considerably less

than this due to the low pH of the forest floor, the low

wind speed in forest stands, and less radiation reaching

the forest floor. Measurements taken both in western

and eastern Washington forests which were fairly open

range from 10% of the initial NH4

+

 being lost with a light

liquid application (dry site) (Henry and Zabowski, 1990),

25% in a western Washington forest with a closed canopy, and 35% lost in an open older forest stand in

western Washington.4

 Current work in British Columbia

with surface applications to hybrid poplar plantations

suggests losses ranging from 25% to 100% of the initial

NH4

+

.

5

 Suggested conservative values in Table 8-7 are

10% in open stands and no ammonia volatilization in

closed stands.

8.8.2.3 Denitrification

Excess NH4

+

 not taken up by the vegetation or immobilized by the soil will in most cases microbially transform

into nitrate. When there is little oxygen in the soil, some

of the NO3

−

 can be lost to the atmosphere as N2 or N2O,

a process called denitrification. Depending on soil conditions, denitrification losses up to 25 percent of the total

can occur (U.S. EPA, 1983). Measurements taken in a

dry eastern Washington forest showed no denitrification

(Henry and Zabowski, 1990), while in a well drained

western forest about 10% denitrification was predicted

(Coles et al., 1992). Table 8-7 contains suggested values for denitrification.

8.8.2.4 Soil Immobilization Rates

Immobilization is the transformation of NH4

+

 into organicN by soil microbes. Because forest soils include an

organic layer containing decaying litterfall, twigs, and

branches, the soil may have a lot of excess organic

carbon both in the forest floor and the surface soil

horizons. When this carbon decomposes, it uses some

of the available N. This immobilization represents longterm soil storage of nitrogen that will be re-released (mineralized) at a very slow rate. Depending on the amount of

carbon and whether the site has been fertilized before,

immobilization can be up to 1,100 kg/ha (Henry, 1991). A

young stand with a good forest floor, however, probably

will immobilize in the neighborhood of 220 kg/ha.

When sewage sludge is re-applied, little additional N will

be immobilized unless the previous application was

made many years before. Table 8-7 contains suggested

values for immobilization. Overestimation of N immobilization at forest sites can result in sewage sludge application rates that significantly exceed tree N requirements.

Consequently, estimates of immobilization should either

be set very conservatively or based on sewage sludge

field studies that document the increase of soil organicN from different horizons.

The carbon to nitrogen ratios (C:N) of the forest floor and

surface soil horizons can serve as indicators of the

potential for soil immobilization of N from sewage sludge

applied to forest sites (excluding large woody debris that

decompose slowly). Generally, when the C:N ratio is

greater than 20-30:1, immobilization will occur. Woody

materials generally have much higher ratios (often exceeding 70:1). When sewage sludge is applied, the

available N allows microbial populations to expand rapidly and decomposes the soil organic matter, temporarily

locking up the N in microbial biomass or in long-term

stable humic acids. The N incorporated into the cell

structure of the microorganisms can eventually be released gradually as they die off.

8.8.2.5 Nitrogen Leaching

Typically, N is the limiting constituent for land applications of sewage sludge because when excess N is

applied, it often results in nitrate leaching. The N available from sewage sludge addition can be microbially

transformed into NO3

−

 through a process known as nitrification. Because NO3

−

 is negatively charged, it easily

leaches to the ground water with percolating rainfall. A

number of studies conducted at the University of Washington’s Pack Forest Research Center confirmed that

heavy applications of N resulted in substantial increases

of NO3

−

 in the ground water (Riekirk and Cole, 1976; Vogt

et al., 1980).6,7 3

 Henry, C., A. Haub, and R. Harrison. Mineralization of sewage

sludge nitrogen from six Oregon cities. Draft report. 4

 See footnote 1.

5 Van Ham, M., and C. Henry. 1995. Personal communication between M. Van Ham and C. Henry, Pack Forest Research Center,

University of Washington, Eatonville, WA.

6 Henry, C., R. King, and R. Harrison. Distribution of nitrate leaching

from application of municipal biosolids to Douglas-fir. Draft report. 7

 Henry, C., and D. Cole. Nitrate leaching from fertilization of three

Douglas-fir stands with municipal biosolids. Draft report.

102
8.8.2.6 Effects of Temperature on Nitrogen

Dynamics

In northern climates where winter soil temperatures are

low, transformations caused by microbial action in soil

slow down considerably. For instance, when the soil

temperature decreases about 18°F, microbial action is

about half as fast. At about 40°F microbial action essentially stops. Through much of the winter the average

temperature of the soil may be at or below 40°F under

forest stands in northern parts of the United States. This

means that mineralization, nitrification, and denitrification essentially stop. Thus, the nutrients from land application of sewage sludge made during the winter will

essentially be stored in the forest floor and soil layers

until temperatures increase. Thus, NO3

−

 leaching will not

significantly occur from winter applications because

NO3

−

 will not be formed.

8.8.3 Calculation Based on Nitrogen for a

Given Year

The calculation for the application rate at forest sites

based on N for a given year involves determining site N

requirements and available N in the sewage sludge. A

site’s net N needs are the sum of the N uptake by trees

and understory and soil immobilization of N:

Nreq = Utr + Uus + SI (8-1)

where:

Nreq = N requirements to be supplied by a given

application of sewage sludge, kg/ha

Utr = N uptake, by trees, kg/ha (Table 8-6)

Uus = N uptake by understory, kg/ha (Table 8-6)

SI = N immobilization in soil from initial sewage sludge application, kg/ha (Table 8-7)

The requirements for N are met by: 1) the N mineralized

from previous applications, and 2) the N supplied by the

current application of sewage sludge (NH4

+

, NO3

−

 and

mineralized ON). Organic-N is converted to NH4

+

 relatively rapidly during the first year. In future years, the

remaining organic matter becomes more and more recalcitrant (does not decompose as easily) and ON mineralization is much reduced. Without local data on

mineralization rates, it is recommended that ON mineralization be ignored beyond three years after application. The N supplied from previous applications is

calculated as shown in equation 8-2.

Nprev = {(S1)(ON1)(1-K0)(K1)

+ (S2)(ON2)(1-K0)(1-K1)(K2)

+ (S3)(ON3)(1-K0)(1-K1)(1-K2)(K3)}1,000 (8-2)

where:

Nprev = Total mineralized N from sewage sludge

applications in previous years, kg/ha

S1,2,etc. = Sewage sludge application rate 1, 2,

etc. years ago, t/ha

ON1,2,etc. = Percent N in sewage sludge 1, 2, etc.

years ago, expressed as a fraction

K1,2,etc. = Mineralization rate of ON 1, 2, etc.

years after the year of application, expressed as a fraction

The amount of N available the year of application from

a ton of the sewage sludge (PAN) is calculated from

equation 8-3.

PAN = {(AN)(1-V) + NN + (ON0)(K0)}(1-D)(10) (8-3)

where:

PAN = Total plant available nitrogen, kg/ton

AN = Percent NH4

+

-N in sewage sludge as applied, %

NN = Percent NO3

−

-N in sewage sludge as applied, %

ON0 = Percent ON in sewage sludge as applied, %

K0 = Mineralization rate of ON during the year

of application, expressed as a fraction

V = Loss of ammonia by volatilization, expressed as a fraction

D = Loss of N by denitrification, expressed

as a fraction

The sewage sludge application rate to supply a given

year’s N requirement is then calculated from the previous two equations:

S0 = (Nreq - Nprev)/PAN (8-4)

Table 8-8 provides some example calculations for a young

plantation and older stand of Douglas-fir. In comparing

Table 8-8. Example First-year Application Rate for Sewage

Sludge Based on Available Nitrogen for Two

Different Types of Douglas-fir Stands

Assumptions

Young

Stand

Older

Stand

Uptake by trees, Utr (kg/ha) 112 50 

Uptake by understory, Uus (kg/ha) 101 28 

Soil immobilization, SI (kg/ha) 224 56 

N required, Nreq (kg/ha) (Eq. 8-1) 437 134 

N mineralization, previous sewage sludge

app., Nprev (kg/ha) (Eq. 8-2; no

previous application)

0 0 

Initial ammonia-N, AN (%) 1.0 1.0

Initial nitrate-N, NN (%) 0.0 0.0

Initial organic-N, ON (%) 4.0 4.0

Fraction of ON mineralized, K0 (g/g) .25 .25

Fraction of ammonia volatilized, V (g/g) .25 .10

Fraction of N lost to denitrification, D (g/g) .25 .10

Plant available N, PAN (kg/t) (Eq. 8-3) 17.5 19.0

Sewage sludge application rate, 

S0 (t/ha) (Eq. 8-4)

33.3 7.8

103
these cases, note that total N requirements are higher

for the young stand than the older stand (390 lb/ac vs

120 lb/ac), and available N in the sewage sludge is lower

in the younger stand due to higher losses from volatilization and denitrification (26.3 lb/ac vs 34.2 lb/ac for the

older stand). Consequently there is a large difference in

sewage sludge application rates to meet N requirements

in the two stands: 14.8 T/ac for the younger stand and

3.5 T/ac for the older stand.

8.8.4 Calculation of Sewage Sludge

Application Rates for First and

Subsequent Years

The sewage sludge application rate in any given year

involves N budget calculations using procedures described in Section 8.8.3 so as not to exceed site N

uptake requirements. Although the basic approach is the

same for any year’s application, special considerations

in performing the N budget analysis will vary somewhat

depending on whether it is an initial application, and

whether subsequent applications are done annually or

periodically (i.e., intervals exceeding one year).

A key consideration in the N budget for an initial application is determination of the amount of N in the sewage

sludge that will be immobilized by the soil (SI in Equation

8-1). Sewage sludge additions will build up the soil N

pools to the point that an equilibrium will eventually exist

between soil N mineralization and immobilization. Thus,

for subsequent annual applications, it should be assumed that there will be no additional soil immobilization. In fact, unless site-specific data documenting its

existence is available, it is prudent to assume no additional soil immobilization unless the last application was

made a considerable time in the past (>5-10 years).

The main difference between periodic applications compared to annual applications is that cumulative applications over the same time period will be lower because

the N available from mineralization of previous sewage

sludge applications will generally be less than the potential N uptake by trees in the years when sewage

sludge is not applied. This means that more total forest

acreage will generally be required for utilization of a

given amount of sewage sludge compared to annual

applications.

8.8.5 Calculation Based on Part 503

Pollutant Limits for Metals

The same Part 503 pollutant limits for metals that pertain

to sewage sludge application at agricultural sites, as

discussed in Chapter 7, also apply to forest sites (see

Chapter 3 for a discussion of pollutant limits).

8.9 Design Example of Sewage Sludge

Application at Forest Sites

This design example was developed in part to demonstrate the procedures needed to ensure protection of

drinking water aquifers during an annual sewage sludge

land application program. The criteria used for an annual

sewage sludge land application project at a forest site are:

1. Nitrogen applications cannot exceed the ability of the

forest plants to utilize the N applied, with appropriate

adjustments for losses.

2. Cumulative metal loading limits cannot exceed the

cumulative pollutant loading rates (CPLRs), if applicable

(see Chapter 3), in the Part 503 rule.

8.9.1 Sewage Sludge Quantity and Quality

Assumptions

The sewage sludge generated by the hypothetical community in this design example is assumed to have the

following average characteristics:

• Anaerobically digested sewage sludge is generated

on the average of 18.2 t/day (20 T/day), dry weight,

by an activated sludge sewage treatment plant.

• Liquid sewage sludge averages 4 percent solids by

weight; its volume is 445,600 L/day (117,600 gal/day).

• Average sewage sludge analysis on a dry weight basis

is the same as the design example for agricultural applications (see Chapter 7 for metals concentrations):

– Organic-N (ON) = 2.5 percent by weight.

– Ammonia-N (AN) = 1 percent by weight.

– Nitrate-N (NN) = none.

8.9.2 Site Selection

The hypothetical community for this design example is

located in the Pacific Northwest. A large commercial

forest is located 24 km (15 mi) from the sewage treatment plant. The site owner believes that he can expect

a significant increase in tree growth rate resulting from

the nutrients in sewage sludge. Preliminary investigations of the owner’s property show that a total of 3,000 ha

(7,400 ac) are available, of which 1,200 ha (3,000 ac) have

the following desirable characteristics:

• Convenient vehicle access to public and private

roads, plus an in-place network of logging roads

within the area.

• No surface waters used for drinking or recreational

purposes are located within the area. Intermittent

stream locations are mapped, and 90-m (290-ft) (or

greater) buffer zones can be readily established

around the stream beds.

104
• Ground water under one portion of the site has the

potential to serve as a drinking water aquifer.

• Public access is limited by signs and fences adjacent

to public roads.

• Topography is satisfactory, in that the area consists

largely of slopes less than 6 percent, and slopes

steeper than 30 percent can be readily excluded from

the sewage sludge application program.

• There are no residential dwelling units within the area.

• The area is roughly equally divided between young

hybrid poplar that is harvested on a 5-year rotation

and an established stand of Douglas-fir. However, the

1,200 ha (3,000 ac) area contains 200 ha (500 ac)

that either contain tree species that are incompatible

with sewage sludge applications (e.g., they fix nitrogen) or have slopes exceeding 30%. These areas are

excluded.

8.9.2.1 Soil and Hydrological Properties of the Site

The soils are of two types: glacial outwash, and residual

soil developed from andesitic bedrock. The glacial outwash is located largely on terraces with slopes less than

10 percent. Infiltration is rapid. The soil pH ranges between 5.5 and 6.0, and CEC is 14 meq/100 g. A 2.5-cm

to 5.0-cm (1-in to 2-in) litter layer exists in the established forest. The ground water table is approximately 9 m

(30 ft) below the soil surface. Residual soil is found on

slopes ranging up to 40 percent. Slopes steeper than 30

percent were eliminated from further consideration.

8.9.3 Determining the Sewage Sludge

Application Rate Based on Nitrogen

For this design example, assume that the sewage

sludge is to be land applied on an annual basis, and that

the quantity of sewage sludge applied is limited by N.

The purpose of the calculation is to have the plant-available

N in the applied sewage sludge equal the N uptake of the

trees and understory, accounting for assumed atmospheric losses discussed in Section 8.8.3. This is a conservative approach intended to prevent leaching of

nitrate to the ground water aquifer.

Step 1. Calculate Net N Requirements for First 5

 Years

N requirements for the hybrid poplar and the Douglas-fir

stands are calculated separately for the first 5 years

using Equation 8-1. Table 8-9 summarizes the assumptions used to calculate net N requirements. For the

hybrid poplar tree, N uptake is assumed to gradually

increase, from 50 kg N/ha in the first year to 250 kg N/ha

in the fifth year. Uptake of the understory is 100 kg N/ha

in the first year and 50 kg N/ha in the second year, and

is assumed to be negligible in subsequent years. The

amount of N immobilized as a result of decomposition

of soil organic carbon is assumed to be 100 kg/ha in the

first year and 0 in subsequent years. Table 8-9 shows a

high N need for the poplar of 250 kg/ha in the first year,

which drops to 100 kg/ha in the second year, and gradually increases back to 250 kg/ha by the fifth year.

Initial N required for the Douglas-fir stand is higher than

for the hybrid poplar (350 kg/ha) because of higher initial

N uptake by trees (100 kg/ha) and higher N immobilization (150 kg/ha) because of higher initial litter/soil

organic carbon content. Understory uptake in the first

year was assumed to be the same as for the hybrid

poplar (100 kg/ha). In subsequent years, N uptake by

trees is assumed to remain steady at 100 kg/ha,

whereas N uptake by the understory and immobilization

is assumed to be negligible. The net effect of these

assumptions is that the N needs for the Douglas-fir

stand in the second through fifth years remain steady at

100 kg/ha, as shown in Table 8-9.

Step 2. Calculate Initial Available N in Sewage

 Sludge for Each Year

Available N in the sewage sludge needs to be calculated

for each forest stand type, and recalculated for any year

in which changing site conditions may affect N availability. In the first two years surface application is made to

a very open stand where both heat and wind reach the

soil surface, thus volatilization can be high (assumed to

be 0.5), but since the soils are well drained, denitrification is low (assumed to be 0.1). Mineralization rate for

this first year is taken from Table 7-7 in Chapter 7 in the

column for anaerobically treated sewage sludge. N

availability from sewage sludge applied to the hybrid

poplar plantation for the first year is calculated using

Equation 8-3 as follows:

Table 8-9. N Requirements for Sewage Sludge Application to

Hybrid Poplar and Established Douglas-fir

Plantations

Year Ntr Nus SI Nreq

kg/ha

Hybrid poplar

1995 50 100 100 250

1996 100 50 0 150

1997 150 0 0 150

1998 200 0 0 200

1999 250 0 0 250

Douglas-fir

1995 100 100 150 350

1996 100 0 0 100

1997 100 0 0 100

1998 100 0 0 100

1999 100 0 0 100

105
PAN1,2 = {(AN)(1-V) + NN + (ON0)(K0)}(1-D)(10)

= {(1.0)(1-0.5) + 0 + (2.5)(0.20)}(1-0.1)(10)

= 9.0 kg/t

During the following years, the trees reduce both radiation and wind reaching the soil surface, so ammonia

volatilization is assumed to be reduced to 0.25, while

denitrification remains relatively constant at 0.1.

PAN3-5 = {(AN)(1-V) + NN + (ON0)(K0)}(1-D)(10)

= {(1.0)(1-0.25) + 0 + (2.5)(0.20)}(1-0.1)(10)

= 11.3 kg/t

Available N from sewage sludge applied to the Douglasfir stand will be 11.3 kg/t for all 5 years because the wind

and heat reaching the forest floor are presumed to be very

similar to the third year conditions in the poplar stand.

Step 3. Calculate First-Year Sewage Sludge 

 Application Rate

First-year sewage sludge application rates to forest sites

can be substantially higher than in subsequent years

because of the initial response of understory growth,

which increases N uptake, and immobilization of N, as

discussed in Section 8.8.2; no mineralization of ON from

previous applications occurs. The initial sewage sludge

application rate is calculated using Equation 8-4:

S0 = (Nreq - Nprev)/PAN

= (250 - 0)/9.0

= 28 t/ha(for the hybrid poplar)

= (350 - 0)/11.3

= 31 t/ha(for the Douglas-fir)

Step 4. Calculate Sewage Sludge Application Rates

 for Subsequent Years

Sewage sludge application rates for subsequent years

must take into account mineralization of organic N from

previous sewage sludge applications. Table 8-10 shows

the results of mineralization calculations for the second

through fifth years. In this example, the second-year

sewage sludge application rate to supply N requirements of the hybrid poplars drops from 27.8 t/ha to 12

t/ha and then gradually increases to 19.2 t/ha in the fifth

year. The Douglas-fir stand shows an even more dramatic drop from 31 t/ha in the first year to 4.7 t/ha in the

second year. The third year application rate for Douglas-fir

increases to 6.8 t/ha, with slight additional increases to 6.4

and 7.5 t/ha for the fourth and fifth years, respectively.

8.9.4 Site Capacity Based on Nitrogen

The design example site has 1,000 ha (2,471 ac) suitable for sewage sludge application, which is roughly

equally divided between established Douglas-fir forest

and the hybrid poplar plantation (assume 500 ha [1,235

ac] of each). The quantity of sewage sludge that can be

applied during the first 5 years is summarized in Table

8-11. Total application in the first year could be as high as

29,400 t. In the second year this drops to 8,400 t, and

gradually increases to 13,300 t by the fifth year.

Table 8-10. Sewage Sludge Application Rates to Meet N

Requirements at Forest Sites

Year Nreq Nprev PAN S0

S

(cumulative)

t/ha

Hybrid poplar

1995 250 0 9 27.8 28

1996 150 42 9 12.0 40

1997 150 32 11.3 10.4 50

1998 200 35 11.3 14.6 65

1999 250 33 11.3 19.2 84

Douglas-fir

1995 350 0 11.3 31.0 31

1996 100 46 11.3 4.7 36

1997 100 23 11.3 6.8 43

1998 100 27 11.3 6.4 49

1999 100 15 11.3 7.5 56

Notes:

 Nreq = N requirements to be supplied by a given application of

sewage sludge, kg/ha

 Nprev = Total mineralized N from sewage sludge applications in

previous years, kg/ha

 PAN = Total plant nitrogen, kg/ton

 S0 = Sewage sludge application rate for a given year

 S = Sewage sludge application (cumulative)

Table 8-11. Maximum Annual Sewage Sludge Application Based on N Requirements

Area Hybrid Poplar Douglas Fir Total

Year (ha) (t/ha) (t) (t/ha) (t) (t)

1995 500 27.8 13,900 31.0 15,500 29,400 

1996 500 12.0 6,000 4.7 2,400 8,400

1997 500 10.4 5,200 6.8 3,400 8,600

1998 500 14.6 7,300 6.4 3,200 10,200 

1999 500 19.2 9,600 7.5 3,700 13,300 

t = metric tonnes.

106
Since the community generates 18.2 t/day (20 T/day),

dry weight of sewage sludge, or 6,643 t/year (7,307

T/year), this would supply sewage sludge applied at the

first year design rate of only one-fourth of the site. This

scenario also requires less than the entire site for reapplication (at the lesser rates of years 2-5). Therefore, the

hypothetical site appears to be of quite sufficient area.

However, careful planning and record keeping will be

required to schedule the amount and location of sewage

sludge applications to maintain a good program.

8.10 References

Coles, J., C. Henry, and R. Harrison. 1992. Gaseous nitrogen losses

from three Douglas-fir stands after reapplication of municipal

sludge. Agron. Abstr. American Society of Agronomy, Madison, WI.

Dyck, W., S. Gower, R. Chapman-King, and D. van der Wal, 1984.

Accumulation in aboveground biomass of Douglas-fir treated with

municipal sewage sludge. (Draft Report.)

Henry, C. 1991. Nitrogen dynamics of pulp and paper sludge to forest

soils. Water Sci. Tech. 24(3/4):417-425.

Henry, C., D. Cole, T. Hinckley, and R. Harrison. 1993. The use of

municipal and pulp and paper sludges to increase production in

forestry. J. Sus. For. 1:41-55.

Henry, C., and R. Harrison. 1991. Literature reviews on environmental

effects of sludge management: Trace metals, effects on wildlife

and domestic animals, incinerator emissions and ash, nitrogen,

pathogens, and trace synthetic organics. Regional Sludge Management Committee. University of Washington, Eatonville, WA.

Henry, C., and D. Zabowski. 1990. Nitrogen fertilization of Ponderosa

pine: I. Gaseous losses of nitrogen. Agron. Abstr., American Society of Agronomy, Madison, WI.

Riekirk, H., and D. Cole. 1976. Chemistry of soil and ground water

solutions associated with sludge applications. In: Edmonds, R.,

and D. Cole, eds. Use of dewatered sludge, as an amendment

for forest growth, Vol. I. Center for Ecosystem Studies, College of

Forest Resources, University of Washington, Eatonville, WA.

Sopper, W. 1993. Municipal sludge use in land reclamation. Boca

Raton, FL: Lewis Publishers.

Stone, E.L. 1968. Microelement nutrition of forest trees: A review. In:

Forest fertilization—Theory and practice. Tennessee Valley

Authority, Muscle Shoals, Al. pp. 132-175.

U.S. EPA. 1984. Environmental regulations and technology: Use and

disposal of municipal wastewater sludge. EPA/625/10-84/003.

Washington, DC.

U.S. EPA. 1983. Process design manual: Land application of municipal sludge. EPA/625/1-83/016.

Vogt, K., R. Edmonds, and D. Vogt. 1980. Regulation of nitrate levels

in sludge, soil and ground water. In: Edmonds, R., and D. Cole,

eds. Use of dewatered sludge as an amendment for forest growth,

Vol. III. Institute for Forest Resources, University Washington, Eatonville, WA.

107
Chapter 9

Process Design for Land Application at Reclamation Sites

9.1 General

This chapter presents design information for application

of sewage sludge to reclamation sites.1

 It is assumed

that the preliminary planning discussed in earlier chapters has been done, that a sewage sludge transportation

system has been selected, and that reclamation sites

are potentially available within a reasonable distance

from the treatment works. Primary emphasis is on the

revegetation of the reclamation site with grasses and/or

trees. If future land use for agricultural production is

planned, the reader should also refer to Chapter 7,

“Process Design for Agricultural Land Application Sites.”

Extensive areas of disturbed land that can benefit from

reclamation exist throughout the United States as a

result of mining for clay, gravel, sand, stone, phosphate,

coal, and other minerals. Also fairly widespread are

construction areas (e.g., roadway cuts, borrow pits) and

areas where dredge spoils or fly ash have been deposited (Sopper and Kerr, 1982). Other areas needing reclamation include clear-cut and burned forests, shifting

sand dunes, landfills, and sites devastated by toxic

fumes. Some disturbed mining sites may be designated

as “Superfund” sites, and applicable regulations may

pertain.

Disturbed land can result from both surface and underground mining operations, as well as the deposition of

ore processing wastes. The Soil Conservation Service

reported that as of July 1, 1977, the minerals industry

had disturbed a total of 2.3 mil ha (5.7 mil ac), of which

about 50 percent was associated with surface mining

(U.S. Soil Conservation Service, 1977). Only about onethird of the disturbed areas was reported to have been

reclaimed. Table 9-1 presents the amount of hectares

under permit for surface, underground, and other mining

operations during the period 1977 to 1986. Table 9-2

presents the number of hectares that have been reclaimed with bonds released during 1977 to 1986—about

40 percent of the land under permit (Sopper, 1993).

Most disturbed lands are difficult to revegetate. These

sites generally provide a harsh environment for seed

Table 9-1. Hectares Under Permit for Surface, Underground,

and Other Mining Operations From 1977 to 1986a

(Sopper, 1993)

Year Total Hectares

1978 68,635

1979 146,002

1980 141,842

1981 153,880

1982 136,568

1983 182,896

1984 265,768

1985 175,057

1986 107,429

Total 1,378,077 

a

 States and Indian tribe lands included in above tabulations were Alabama, Alaska, Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky,

Louisiana, Maryland, Missouri, Montana, New Mexico, North Dakota,

Ohio, Pennsylvania, Tennessee, Texas, Utah, Virginia, Washington,

West Virginia, Wyoming, Crow Tribe, Hopi Tribe, Navajo Tribe.

Table 9-2. Number of Hectares Reclaimed With Bonds Released

During 1977 to 1986a (Sopper, 1993)

Year Total Hectares

1978 19,078

1979 42,580

1980 51,401

1981 52,547

1982 80,351

1983 69,874

1984 96,910

1985 81,696

1986 68,280

Total 562,717

a

 States and Indian tribe lands included in above tabulations were Alabama, Alaska, Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky,

Louisiana, Maryland, Missouri, Montana, New Mexico, North Dakota,

Ohio, Pennsylvania, Tennessee, Texas, Utah, Virginia, Washington,

West Virginia, Wyoming, Crow Tribe, Hopi Tribe, Navajo Tribe.

1

 40 CFR Part 503 defines a reclamation site as drastically disturbed

land that is reclaimed using sewage sludge (see Chapter 3).

109
germination and subsequent plant growth. Major soil

problems may include a lack of nutrients and organic

matter, low pH, low water-holding capacity, low rates of

water infiltration and permeability, poor physical properties, and the presence of toxic levels of trace metals. To

correct these conditions, large applications of lime and

fertilizer may be required, and organic soil amendments

and/or mulches also may be necessary.

Pilot- and full-scale demonstration projects have shown

that properly managed sewage sludge application is a

feasible method of reclaiming disturbed land and can

provide a cost-effective option for sewage sludge use.

According to the 1990 NSSS, 65,800 dry metric tons per

year (1.2 percent of the sewage sludge used or disposed of annually) are used for land reclamation (58 FR

9257). Table 9-3 lists some of the more significant land

reclamation projects using sewage sludge during the

past 20 years. Research has shown that good plant

cover can be established on many types of disturbed

lands using sewage sludge, which is superior to inorganic fertilizer for such uses (Sopper, 1993). Sewage

sludge has been found to have a beneficial effect on the

establishment and growth of grass and legume species

on mine land (Sopper, 1993). In addition, the pH buffering capacity of sewage sludge makes it beneficial in the

reclamation of acidic sites (Gschwind and Pietz, 1992).

At reclamation sites, sewage sludge application usually

is performed once. The sewage sludge is not applied

again to the same land area at periodic intervals in the

future, as is the case at agricultural and forest sites.

Thus, most reclamation projects must have a continuous supply of new disturbed land on which to apply

sewage sludge in future years. This additional disturbed

land may be created by ongoing mining or mineral processing operations or may consist of presently existing

large areas of disturbed land which are gradually reclaimed. In either case, an arrangement is necessary

with the land owner to allow for future sewage sludge

land application throughout the life of the sewage sludge

land application project.

9.2 Consideration of Post-Sewage

Sludge Application Land Use

If land application of sewage sludge is used in the

reclamation process, it is important to consider federal

and state mining regulations concerning revegetation

(e.g., 30 CFR Parts 816 and 817) and the federal Surface Mining Control and Reclamation Act (Public Law

95-87, Section 515) (U.S. Department of Interior, 1979;

Federal Register, 1982) and its amendments (54 FR 23).

Regulations established under this Act require that a

diverse, effective, and permanent vegetative cover of

the seasonal variety native to the affected land must be

established and must be capable of self-regeneration

and plant succession equal in coverage to the natural

vegetation of the area (Federal Register, 1982). Before

beginning a land application project using sewage

sludge at a reclamation site, the final use of the site after

it has been reclaimed must be considered regarding

compliance with these regulations. If the post-mining

land use is to be agricultural production or animal grazing, agricultural land application requirements for sewage sludge must be followed, such as the federal Part

503 regulation and any applicable state regulations. If

the site is to be vegetated primarily for erosion control,

a single large application of sewage sludge is desirable

for rapid establishment of the vegetative cover. Generally, Part 503 requirements for agricultural, forest, and

reclamation sites are the same (see Chapter 3). As

discussed in Section 9.3.1.1, the Part 503 regulation

specifies that for land reclamation, the permitting authority can authorize a variance from the agronomic rate

requirement for sewage sludge application.

In humid regions, a majority of the reclaimed mine areas

have been planted to forests. Some of these areas are

managed for lumber or pulp production, while others are

allowed to follow natural succession patterns. If the reclaimed area is to be turned into forest land, larger sewage

sludge application rates can be considered than those

used for agricultural crops, since the products from the

forest are generally not a factor in the human food chain.

In all cases, post-mining land use must be considered prior

to the use of sewage sludge in land reclamation.

9.2.1 Mining Regulations

Prior to mining, a plan must be submitted to the appropriate agency stating the method of reclamation and

post-mining land use. Amended regulations under the

Surface Mining Control and Reclamation Act issued in

1982 and 1988 set forth the following requirements:

• The permanent vegetative cover of the area must be

at least equal in extent of cover to the natural vegetation of the area and must achieve productivity levels

comparable to unmined lands for the approved postmining land use. Both native and introduced species

may be used.

• The period of responsibility begins after the last year

of augmented seeding, fertilization, irrigation, or other

work that ensures revegetation success.

• In areas of more than 26 inches of average annual

precipitation, the period of extended responsibility will

continue for not less than 5 years. In areas with 26

inches of precipitation or less, the period of responsibility will continue for not less than 10 years.

• Normal husbandry practices essential for plant establishment would be permitted during the period of responsibility so long as they can reasonably be

expected to continue after bond release.

110
Table 9-3. Recent Land Reclamation Projects With Municipal Sludge (Adapted From Sopper, 1993)

Sludge

Type of Disturbed Land State Typea Application Rates

(mg/ha) Plant/Animal Studied

Parameters 

Testedb

Acid strip mine spoil PA Dig.-D + effluent 5-20 cm Ryegrass

Hybrid poplar

WA

Deep mine anthracite refuse PA Dig.-D 0, 40-150 10 tree spp.

5 Grass spp.

5 Legume spp.

GR 

PA 

SA 

WA

Acid strip mine spoil

Top-soil strip mine spoil (49 sites)

PA Dig.-D,C 134 Tall fescue

Orchardgrass

Birdsfoot trefoil

Ryegrass

GR 

PA 

SA 

WA

Zinc smelter site PA Dig.-D 47 5 Grass species

5 Legume species

11 Tree species

GR 

PA 

SA

Acid strip mine spoil PA Dig.-D,C/C 120-134 Microorganisms SO,SA

Abandoned Pyrite mine VA Dig.-D 82-260 Tall fescue Lespedeza

Weeping lovegrass

Wheat, rye, oats

GR

PA

SA

WA

Sandstone and siltstone mine soil VA Dig.-D 22, 56, 112, 224 Tall fescue GR 

SA,PA

Non acid-forming overburden VA Dig.-D,C 112 Hay/pasture seed mix SA

Borrow pit SC Dig-D 0, 17, 34, 68 Tall fescue

Sweetgum

GR 

PA

Acid strip mine spoil WV Dig.-D,C Various (NI) Blueberries GR

PA

Overburden minesoil WV Dig.-D 0, 22.4, 44.8, 78.4 Red clover

Tall fescue

Orchardgrass

Birdsfoot trefoil

SA,PA 

GR

Iron ore tailings WI Dig.-D 42-85 5 Native prairie grasses

4 Prairie forbes

Foxtail

GR

Taconite tailings WI Dig.-D 28-115 4 Grass-legume mixtures GR

Copper mine spoil CO Dig.-D 0, 30, 60 Fourwing saltbush

Mountain big sagebrush

GR,PA,SA

Copper mine

Borrow pit

Kaolin spoil

Marginal land

TN

GA

Dig.-D 0, 34, 69, 275 Pine species

Sweetgum

GR,SA

Acid stripmine spoil IL Dig.-L 0, 31-121 Tall fescue

Weeping lovegrass

GR 

WA

Acid stripmine spoil KY (NI) 28-96 European alder

Blacklocust

Cottonwood

Loblolly pine

Northern red oak

GR

PA

SA

Reconstructed prime farmland KY Dig.-D 0, 22.4, 448 Grain sorgham

Corn

GR 

PA,SA

C and D canal dredge material MD Dig.-D 112 KY bluegrass

Tall fescue

Red fescue

Weeping lovegrass

PA 

SA

WA

C and D canal dredge material DE Dig.-D 100 Tall fescue

Red fescue

KY bluegrass

PA 

SA

111
• In areas of more than 26 inches of precipitation, the

vegetative cover and production of pasture, grazing

land, and cropland shall be equal to or exceed the

success standard only during any 2 years except the

first year. Areas approved for other uses shall equal

or exceed success standards during the growing season of the last year of the responsibility period. In

areas with less than 26 inches of precipitation, the

vegetative cover must be equal to the success standard

for at least the last 2 years of the responsibility period.

• The ground cover, productivity, or tree stocking of the

revegetated area shall be considered equal to the

success standards approved by the regulatory authority

when they are not less than 90 percent of the success

standard with 90 percent statistical confidence.

Under the federal mining regulations, the potential postmining land use must be of a level equal to or higher

than the pre-mining land use. Typical land uses include:

• Wilderness or unimproved use.

• Limited agriculture or recreation with little development, such as forest land, grazing, hunting, and fishing.

• Developed agriculture or recreation, such as crop

land, water sports, and vacation resorts.

• Suburban dwellings or light commercial and industry.

• Urban dwelling or heavy commercial and industry.

Many of these land uses are compatible with sewage

sludge application.

9.3 Nutrients, Soil pH, and Climate

Considerations

9.3.1 Nutrients

During mining and regrading operations, the original

surface layers are usually buried so deeply that the soil

nutrients present are not available to plants in the disturbed soil. Nitrogen and phosphorus are often deficient

on disturbed lands, with phosphorus often being the

most limiting fertility factor in plant establishment. Sewage sludge is generally an excellent source of these

nutrients. The amount of sewage sludge applied at one

time during land reclamation can be relatively large (7

to 450 dry t/ha or 3 to 200 T/ac) to ensure that sufficient

nutrients, as well as organic matter, are introduced into

the soil to support vegetation until a self-sustaining ecosystem is established. The local agricultural experiment

station or Cooperative Extension Service can provide

recommendations for the additional quantities of N, P,

and K required to support vegetation for the site.

9.3.1.1 Nitrogen

An advantage of using sewage sludge for land reclamation is that it is a slow-release source of organic nitrogen

fertilizer that will supply some nitrogen for 3 to 5 years.

Depending on the treatment process, much of the original wastewater nitrogen is in the organic form and therefore not immediately available for plant use until it is

converted to inorganic nitrogen by mineralization, making it available to plants. This process is discussed in

Chapters 4 and 7.

Under the federal Part 503 regulation, the permitting

authority may authorize for reclamation sites a sewage

sludge application rate greater than the agronomic rate

for N. The person who applies the sewage sludge must

be able to show that N application in excess of crop and

vegetative requirements would not contaminate ground

water or surface water. The permitting authority may

allow a temporary impact on the reclamation site (e.g., may

allow one application only, at a higher application rate).

The amount of nitrogen needed to establish vegetation

on a reclamation site depends on the type of vegetation

to be grown and the amount of nitrogen available in the

soil. The designer should have information on:

Sludge

Type of Disturbed Land State Typea Application Rates

(mg/ha) Plant/Animal Studied

Parameters 

Testedb

Acid stripmine spoil OH Dig.-D 11-716 Tall fescue GR,PA

SA,WA

Degraded, Semiarid Grassland NM Dig.-D 0, 22.5, 45, 90 Blue gamma

Galleta

Bottlebrush squirreltail

GR,PA,SA

Zn smelter surroundings OK Dig.-L + effluent 2.5-34 cm 10 grass spp.

1 legume

GR 

PA 

SA

Lignite overburden TX Dig.-D 56 NA SA,WA

a

 Dig. = digested, L = liquid, D = dewatered, C = composted, C/C = dewatered cake and compost mix, NI = no information.

b

 GR = growth responses, PA = plant tissue analysis, SA = soil analysis, WA = water analysis, SO = soil organisms, PO = pathogenic organisms,

AH = animal health, NA = not applicable.

Table 9-3. (continued)

112
• The amount and type of nitrogen in the sewage

sludge (organic N, ammonium, and nitrate).

• The plant-available nitrogen content of the existing

soil, if available.

• The fertilizer nitrogen requirements of the vegetation

planned for the site.

This information is used to determine the sewage sludge

application rate so that sufficient nitrogen is applied for

the vegetation but is not in excessive amounts that could

cause unacceptable levels of nitrate leaching into surrounding ground water, as shown in Section 9-7.

The designer should also consider the postreclamation

land use when determining the amount of nitrogen needed

to supply the vegetative needs. If the vegetation grown is

to be harvested and removed from the site, supplemental

nitrogen applications may be needed periodically to maintain adequate productivity. If the reclaimed area is reforested or the vegetation grown is not harvested, most of the

nitrogen will remain on the site and be recycled through

leaf fall and vegetation decomposition.

Sewage sludge applications on mine land usually increase

the total nitrogen concentration in the foliage of vegetation

(Sopper, 1993). It has been speculated that while excessively high nitrogen concentrations in plants do not harm

the plants themselves, they could cause metabolic disruptions in foraging animals. No published documentation of

this phenomenon exists, however (Sopper, 1993).

Drastically disturbed lands can be divided into two categories—those requiring topsoil enhancement and those

without topsoil. On sites with topsoil, an agricultural

application rate might be used, with relatively small

quantities of sewage sludge being applied annually (as

discussed in Chapter 7). On abandoned sites or sites

without topsoil replacement, however, a much larger

application of sewage sludge may be necessary to establish vegetation and improve the physical status of the

soil. Soil fertility is also increased by the nitrogen and

phosphorus in sewage sludge as well as the many micronutrients in sewage sludge necessary for plant growth.

9.3.2 Soil pH and pH Adjustment

Most grasses and legumes, as well as many shrubs

and deciduous trees, grow best in the soil pH range

from 5.5 to 7.5, and pH adjustments may be necessary

at reclamation sites.

Several states have adopted regulations stating that where

sewage sludge is applied to land, the soil pH must be

adjusted to 6.0 or greater during the first year of initial

sewage sludge application and 6.5 during the second year

(Pennsylvania Department of Environmental Resources,

1988). In addition, the soil pH of 6.5 may need to be

maintained for 2 years after the final sewage sludge application. This is recommended because trace metals are

more soluble under acidic conditions than neutral or

alkaline conditions. If the soil pH is not maintained above

6.0 and is allowed to revert to more acidic levels, some

trace metals in the sludge may become soluble; once in

solution, the metals would be available for plant uptake.

Lime often is used for pH adjustment, but other agents

also are feasible. Recommendations for pH adjustment

can usually be obtained by sending soil samples to a

qualified laboratory or the agricultural experiment station

soil testing lab at the nearest land grant college or

university. Common soil tests for lime requirements

often seriously underestimate the lime requirement for

sulfide-containing disturbed lands. In addition, the application of sewage sludge on disturbed lands may cause

further acidification. This must be taken into consideration in calculating lime requirements.

9.3.3 Factors Affecting Crop Yields at

Reclamation Sites

Where sewage sludge is applied at reclamation sites for

agricultural production, crop yields can be variable. Limiting factors can include climatic conditions and shallow

rooting depths (Gschwind and Pietz, 1992). Peterson et al.

(1982) found that adequate moisture and essential elements for crop needs were critical for corn yields grown

immediately after land leveling on sewage sludgeamended soil at a strip mine reclamation site. Pietz et al.

(1982) found that important parameters were shallow rooting depth, soluble salts, moisture stress, and element

interactions in plant tissue, sewage sludge, and soil.

9.3.4 Special Considerations for Arid Lands

When sewage sludge is land applied to reclamation

sites in arid climates, the concentration of soluble salts

in the sludge should be considered. Accumulation of

salts can hinder revegetation of native grasses because

of competition from salt-tolerant, early successional plants

(Jacobs et al., 1993). Other considerations for sewage

sludge application to arid lands are discussed in Chapter 7.

9.4 Vegetation Selection

9.4.1 General

Many plant species have been successfully established

at reclamation sites. Each site should be considered

unique, however, and plant species or seed mixtures to

be used should be carefully selected. Local authorities

should be consulted for recommendations of appropriate species and varieties of plants as well as plant

establishment techniques. Revegetation suggestions

for various regions of the United States are presented

in Tables 9-4 through 9-14. Table 9-15 presents some

successful plant species and species mixtures used in

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sewage sludge reclamation projects. Food crop selection is discussed in Chapter 7.

Plant species to be used should be selected for their

ability to grow under drought conditions and their tolerance for either acid or alkaline soil material. Salt tolerance is also desirable.

If the goal of the reclamation effort is to establish a

vegetative cover sufficient to prevent erosion, a perennial grass and legume mixture is a good crop selection.

It is important to select species that are not only compatible, but also grow well when sewage sludge is used

as the fertilizer. A combined grass and legume seeding

mixture allows the grass species to germinate quickly

Table 9-4. Humid Eastern Region Vegetation

Various grasses, legumes, trees, and shrubs have been evaluated for use on disturbed lands in the humid regions of the United

States. Grass species that have shown promise for use on low pH soils in the eastern United States include weeping lovegrass,

bermudagrass varieties, tall fescue, chewings fescue, switchgrass, red top, colonial bentgrass, creeping bentgrass, velvet bentgrass,

deertongue, big bluestem, little bluestem, and brown sedge bluestem (Bennett et al., 1978).

Some of the more agriculturally important grass species adapted to better soil conditions on disturbed sites include bromegrass,

timothy, orchardgrass, perinnial rye grass, Italian ryegrass, Kentucky bluegrass, Canadian bluegrass, Reed canarygrass, Dallisgrass,

bahiagrass, and in special situations, lawn grasses including Zoysia japonica Steud and Zoysia matrella. In addition to the common

grasses, several of the cereal grains, such as rye, oats, wheat, and barley have been used, but mainly as companion crops (Bennett

et al., 1978).

Legume species tested on disturbed sites in eastern United States include alfalfa, white clovers, crimson clover, birdsfoot trefoil,

lespedezas, red clover, crownvetch, and hairy vetch. Other species that have been successfully tested include flat pea, kura clover,

zigzag clover, sweet clover, and yellow sweet clover (Bennett et al., 1978).

Several grass and legume mixtures have been used successfully in Pennsylvania to revegetate drastically disturbed lands amended

with municipal sludges. The primary mixture and seeding rate used for spring and summer seeding is:

Species Amount kg/ha

Kentucky-31 tall fescue 22

Orchardgrass 22

Birdsfoot trefoil 11

Total 55

Metric conversion factor:

 1 kg/ha = 0.89 lb/ac.

For late summer and early fall seeding the following mixture has been used successfully:

Species Amount kg/ha

Kentucky-31 tall fescue 11

Orchardgrass 5

Winter rye (1 bu/ac) 63

Total 79

Metric conversion factor:

1 kg/ha = 0.89 lb/ac.

This mixture has usually been sufficient to establish a vegetative cover to protect the site over the winter season. The following

spring, an additional seed mixture, consisting of orchardgrass (11 kg/ha; 9.8 lb/ac) and birdsfoot trefoil (11 kg/ha; 9.8 lb/ac), is

applied. Other seeding mixtures for spring, summer, and fall seeding are found in Rafaill and Vogel, 1978.

Several tree and shrub species have been utilized on disturbed land areas in the eastern United States. However, in general, trees

and shrubs have been planted either after the soil has been stabilized with herbaceous species, like grasses and legumes, or has

been planted with them. On certain drastically disturbed areas, trees may be the only logical choice of vegetation where a future

monetary return is expected. They do provide long-term cover and protection with little or no additional care and maintenance. The

same precautions should be exercised in selecting tree species for use on disturbed land sites as in selecting grasses and legumes.

The soil acidity, plant nutrient requirements, chemical and physical properties of the soil, site topographical influences, and other

environmental factors should be considered.

Common tree and shrub species grown successfully on disturbed land sites in the eastern United States include black locust,

European black alder, autumn olive, white pine, scotch pine, Virginia pine, short leaf pine, red pine, Norway spruce, European and

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Table 9-6. Western Great Lakes Region

This region includes Wisconsin, eastern Minnesota, and the western upper peninsula of Michigan. The common grasses, generally

used in mixtures with a legume, are tall fescue, smooth brome, and timothy. Kentucky bluegrass and orchardgrass are also well

adapted. “Garrison” creeping foxtail and reed canarygrass perform well on wet sites. The most commonly used legumes are

birdsfoot trefoil and crownvetch. Numerous species of woody plants can be used depending on specific site conditions. Siberian

crabapple, several species of poplars, tatarian and Amur honeysuckles, silky dogwood, redosier dogwood, European black alder,

black cherry, and green ash perform well. Autumn olive is adapted to the southern portion of this area.

Table 9-7. Northern and Central Prairies

This is the region known as the Corn Belt. Grasses adapted to the area are Kentucky bluegrass, tall fescue, smooth brome, timothy,

and orchardgrass. Reed canarygrass is adapted to wet areas. Switchgrass, big bluestem, and Indiangrass are well adapted warm

season natives. Birdsfoot trefoil, crownvetch, and alfalfa are commonly used legumes.

Woody species that have been successful include autumnolive, European black alder, poplar species, tatarian honeysuckle, Amur

honeysuckle, black cherry, eastern red cedar, pines, oaks, black walnut, green ash, black locust, black haw, and osage-orange.

Table 9-8 Northern Great Plains

This region includes most of the Dakotas and Nebraska west to the foothills of the Rocky Mountains and includes northeastern

Colorado. The native wheatgrass (western, thickspike, bluebunch, streambank, and slender) are used extensively in seeding

mixtures. Western wheatgrass should be included in most mixtures, although for special purposes thickspike or streambank

wheatgrass are more appropriate. Green needlegrass is an important component of mixtures except in the drier areas. On favorable

sites big bluestem, little bluestem, and switchgrass provide opportunities for color or for a different season of use. Prairie sandreed is

adapted to sandy soils throughout the region. “Garrison” creeping foxtail and reed canarygrass are adapted to wet sites.

Crested wheatgrass has been used extensively and is long-lived in this climate. Intermediate and pubescent wheatgrasses are

useful in establishing pastures. The use of smooth brome and tass fescue is limited to the eastern portions of the Northern Great

Plains where the annual precipitation exceeds 50 cm (19.7 in). Alfalfa and white sweetclover are the only legumes used in most of

the area for reclamation plantings.

Many native and introduced woody plants are adapted for conservation plantings. Fallowing to provide additional moisture is required

for establishment of most woody plants and cultivation must generally be continued for satisfactory performance of all but a few

native shrubs. These practices may not be compatible with certain reclamation objectives, thereby limiting the use of woody species

to areas with favorable moisture situations. Some woody plants useful in this area, if moisture and management are provided, are

Russian-olive, green ash, skunkbush sumac, Siberian crabapple, Manchurian crabapple, silver buffaloberry, tatarian honeysuckle,

chokecherry, Siberian peashrub, Rocky Mountain juniper, and willow species.

Table 9-5. Drier Mid-West and Western Region Vegetation

A large number of plant species have been tested on disturbed lands in the Intermountain Region of the United States (Berry, 1982).

Fewer species have been evaluated for reclamation use in the drier regions of the United States. The objective in many reclamation

plantings in the drier regions is to return the area to climax vegetation. In almost every instance, the soils are not the same as

before the disturbance occurred, and it would seem in many cases that species lower in the successional stage may be better

adapted and more easily established on these sites. Whether a single species or a mixture is selected depends on several factors,

including the planned future use of the site, the desire to have the planting blend with the surrounding vegetation, and the

adaptability and compatibility of the species selected. The factors limiting the successful establishment of vegetation on disturbed

areas may be different on a site being reclaimed than on adjacent undisturbed areas, where a plant species may be growing

together in what appears to be a stable community. Even after the species have been selected, the proportionate amounts of

seeding are not easily determined. The successful experiences of the past 40 years from seeding range mixtures and planting

critical areas appears to be the best guide to the opportunities for success of either single species or mixtures (Berg, 1978).

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Table 9-9. Southern Great Plains

The Southern Great Plains are considered to be the area from southcentral Nebraska and southeastern Colorado to central Texas.

The most common native grasses of value in reclaiming drastically disturbed lands include big bluestem, little bluestem, Indiangrass,

switchgrass, buffalograss, blue grama, sideoats grama, and sand lovegrass. Introduced bluestems such as yellow bluestem,

Caucasian bluestem, and introduced kleingrass, blue panicgrass, and buffelgrass are important in the southern and central portions

of this plant growth region. Alfalfa and white sweetclover are the most commonly used legumes. Russian-olive is a satisfactory

woody species in the northern portions and along the foothills of the Rocky Mountains. Junipers, hackberry, and skunkbush sumac

are important native species. Osage-orange is well adapted to the eastern part of this area. Desirable woody plants require special

management for use on most drastically disturbed lands.

Table 9-10. Southern Plains

This area is the Rio Grande Plains of south and southwest Texas. The characteristic grasses on sandy soils are seacoast bluestem,

two-flow trichloris, silver bluestem, big sandbur, and tanglehead. The dominant grasses on clay and clay loams are silver bluestem,

Arizona cottontop, buffalograss, curlymesquite, and grama grasses. Indiangrass, switchgrass, seacoast bluestem, and crinkleawn are

common in the oak savannahs.

Old World bluestems, such as yellow and Caucasian bluestems, are satisfactory only where additional moisture is made available.

Natalgrass and two-flower trichloris have shown promise in reclamation plantings.

Table 9-11. Southern Plateaus

The area is made up of the 750- to 2,400-m (2,450- to 7,875-ft) altitude plateaus of western Texas, New Mexico, and Arizona. The

area includes a large variety of ecological conditions resulting in many plant associations. Creosote-tarbush desert shrub, grama

grassland, yucca and juniper savannahs, pinyon pine, oak, and some ponderosa pine associations occur. Little bluestem, sideoats

grama, green sprangletop, Arizona cottontop, bush muhly, plains bristlegrass, vine-mesquite, blue grama, black grama, and many

other species are common and are useful in reclamation plantings, depending on the site conditions and elevation.

Table 9-12. Intermountain Desertic Basins

This region occupies the extensive intermountain basins from southern Nevada and Utah, north through Washington, and includes

the basin areas of Wyoming. The natural vegetation ranges from almost pure stands of short grasses to desert shrub. There are

extensive area dominated by big sagebrush or other sagebrush species.

A wide variety of species of grasses is available for this area. Among the most commonly used species are the introduced Siberian

wheatgrass, crested wheatgrass, intermediate wheatgrass, pubescent wheatgrass, tall wheatgrass, and hard fescue. Native grasses

used include bluebunch wheatgrass, beardless wheatgrass, big bluegrass, Idaho fescue, and Indian ricegrass. Four-wing and Nuttall

saltbush have performed well in planting trials. Available woody species are limited, though junipers, Russian-olive, skunkbush

sumac, and other native and introduced woody plants are adapted to the climate where moisture is adequate.

Table 9-13. Desert Southwest

This is the desert of southwestern Arizona, southern Nevada, and southern California. Creosotebush may occur in almost pure

stands or with tarbush. Triangle bur-sage, white bur-sage, rubber rabbitbrush, and ocotillo are prominent on some sites. Large

numbers of annual and perennial forbs are present. Saltbushes, winterfat, and spiny hopsage are common. The few grasses present

in the understory are largely big galleta, desert saltgrass, grama grasses, and species of threeawns.

Only minor success has been obtained in establishing vegetation on disturbed lands in the desert southwest. Irrigation for

establishment may be essential in some areas, and the longevity of stands when irrigation is discontinued is not known. Big galleta

and bush muhly show promise. Native shrubs such as creosotebush, fourwing saltbush, and catclaw have also been established.

Reseeding annuals such as goldfields, California poppy, and Indianwheat have also shown promise.

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Table 9-14. California Valleys

The climate of the central California Valleys is classified as semiarid to arid and warm and the moisture is deficient at all seasons.

The largest area of grassland lies around the edge of the central valley and is dominated by annual species. The only areas

remaining in grass in the valley are usually too alkaline for crop production. The grasses remaining in these sites are desert

salt-grass and alkali sacaton.

Recommended for seeding in the area of more than 40 cm (15.8 in) annual precipitation is a mixture of “Luna” pubescent

wheatgrass, “Palestine” orchardgrass, and rose clover. Crimson clover, California poppy, and “Blando” brome can be added.

Inland in the 30 cm (12 in) precipitation areas, a mixture of “Blando” brome, Wimmera ryegrass, and “Lana” woolypod vetch is

recommended. In the 15- to 30-cm (6 to 12 in) precipitation zone “Blando” brome (soft chess) and rose clover are generally used.

State Species Seeding Rate (kg/ha-1)

CO Slender wheatgrassa 5.1

Intermediate wheatgrassa 4.8

Pubescent wheatgrassa 4.6

Crested wheatgrassa 3.8

Smooth bromea 4.6

Meadow bromea 2.6

Timothya 1.5

Orchardgrassa 1.4

IL Tall fescue 22

Weeping lovegrass 8

IL K-31 tall fescue 22

Weeping lovegrass 7.8

IL Common bermudagrassa 11

Sericea lespedezaa 28

Kobe lespedezaa 11

Perennial rye grassa 22

Potomac orchardgrassb 17

Sericea lespedezab 22

Kobe lespedezab 11

Potomac orchardgrassc 22

Penngift crownvetchc 17

IL Tall fescue 25

Perennial ryegrass 25

Western wheatgrass 25

IL Reed canarygrass 34

Tall fescue 46

Redtop 17

IL Alfalfaa 22.9

Bromegrassa 9.5

Tall fescuea 9.1

MD Tall fescue 40

Birdsfoot trefoil 10

OH Fall, balbo rye 9.6 (bu/ha-1)

State Species Seeding Rate (kg/ha-1)

Spr., K-31 tall fescuea 11

Korean lespedezaa 3.4

Sweet clovera 3.5

Orchardgrassa 3.3

OK Switchgrass 154 

Kleingrass 154 

PA Reed canarygrass 224 

Tall fescue 224 

Orchardgrass 224 

Birdsfoot trefoil 224 

Crownvetch 224 

Deertongue 224 

Switchgrass 224 

Alfalfa 224 

Ladino clover 224 

PA K-31 tall fescuea 39

Birdsfoot trefoila 8

Rye grassa 6

PA Tall fescuea 22

Orchardgrassa 22

Birdsfoot trefoila 11

Crownvetcha 11

PA Blackwell switchgrass 17

Niagara big bluestem 34

Birdsfoot trefoila 22

K-31 tall fescuea 45

Perennial ryegrassb 22

Lathco flatpeab 67

Oahe intermediate

Wheat grass 34

Tall fescuec 22

Orchardgrassc 22

Crownvetchc 17

Table 9-15. Some Sucessful Plant Species and Species Mixtures Used in Various Sludge Reclamation Projects (Sopper, 1993)

117
and provides a complete protective cover during the first

year, while also allowing time for the legume species to

become established and develop into the final vegetative cover. The grasses will also take up a large amount

of the nitrogen, preventing it from leaching into the

ground water. Since legume species can fix nitrogen

from the atmosphere, additional sewage sludge nitrogen

additions are often unnecessary.

If a site is to be reforested, it is still generally desirable to

seed it with a mixture of grasses and legumes. The initial

grass and legume cover helps to protect the site from

erosion and surface runoff and takes up the nutrients

supplied by the sewage sludge. Planting slow-growing

tree species is generally not recommended because of

the extreme competition from the fast-growing herbaceous vegetation. Fast-growing hardwoods seem to

survive and grow well because they can usually compete

successfully. Suitable species might be black locust, hybrid

poplar, European alder, Catalpa, and European larch.

9.4.2 Seeding and Mulching

Herbaceous species can be seeded by direct drill or

broadcast, hydroseeding, or aerial seeding. Disturbed

sites, however, often are too rocky and irregular for drill

seeding. Broadcast seeding is generally more desirable

because the stand of vegetation produced is more natural in appearance, with a more uniform and complete

cover, and is effective in erosion prevention and site

stabilization. Broadcasting also achieves a planting

depth that is better suited to the variety of different sized

seeds usually found in mixtures of species. Aerial broadcast seeding may also be useful for large tracts. It is

generally not necessary to cover the seed, since the first

rainfall will normally push the seed into the loosened

surface spoil and result in adequate coverage.

On sites that have good topsoil, agricultural seeding

rates can be used. On abandoned sites, however, it may

be necessary to apply much larger amounts of seed

(Sopper and Seaker, 1983). Mulching is generally not

necessary except on specific sites. Mulching involves

applying organic or inorganic materials to the soil surface to protect the seed, reduce erosion, modify extremes in surface spoil temperatures, and reduce

evaporation. Mulching is generally advisable on steep

slopes and on black anthracite refuse or fly ash banks

to protect germinating vegetation from high surface temperatures, which may be lethal to most plants. Mulching

may also be required by some state regulatory agencies

for specific situations. Materials used for mulching are

straw, hay, peanut hulls, corn cobs, bagasse, bark, sawdust, leaves, and wood chips.

9.5 Sewage Sludge Application Methods

9.5.1 Transportation

Chapter 14 discusses sewage sludge transport in detail.

A special consideration in transport of sewage sludge to

reclaimed mined land is the potential to backhaul sewage sludge (i.e., use the same trucks, railcars, etc., that

transport the mined ore to the city for transporting the

sewage sludge from the city back to the mining area).

For example, in 1981-82, the city of Philadelphia backhauled about 54,432 t (60,000 T) of sewage sludge

annually in coal trucks a distance of 450 km (280 mi) to

State Species Seeding Rate (kg/ha-1)

PA K-31 tall fescuea 22

Orchardgrassa 22

Birdsfoot trefoila 11

Crownvetcha 11

VA Tall fescuea 8.4

Perennial ryegrassa 8.4

Annual ryegrassa 8.4

Tall fescueb 22

Perennial ryeb 22

Sericea lespedezab 22

Black locustb 0.8

VA K-31 tall fescuea 67

Redtopa 5.6

Table 9-15. (continued)

State Species Seeding Rate (kg/ha-1)

Ladino clovera 5.6

VA Tall fescue 67.3

Weeping lovegrass 22

Korean lespedeza 11.2

VA Ky-31 tall fescue 80

WI Canada bluegrassa 11

Red clovera 9.7

Smooth bromeb 15.2

Alfalfab 11

Western wheatgrassc 9.7

Alsike cloverc 11

Barleyd 16.5

Japanese milletd

(added to above mixtures)d 8.6

a-d Species with the same superscript letter represent a seeding mixture.

118
help reclaim strip mine sites in western Pennsylvania

(Sopper et al., 1981).

9.5.2 Site Preparation Prior to Sewage

Sludge Application

Under federal and state mining regulations, disturbed

mine sites generally must be graded after mining to the

approximate original contour of the area. Abandoned

areas where no regrading has been done should also

be regraded to a relatively uniform slope of less than 15

percent prior to sewage sludge application.

9.5.2.1 Scarification

Prior to sewage sludge application, the soil surface

should be roughened or loosened to offset compaction

caused during the leveling or grading operation. This will

help to improve surface water infiltration and permeability

and slow the movement of any surface runoff and erosion. A heavy mining disk or chisel plow is typically

necessary to roughen the surface. It is advisable that

this be done parallel to the site contours.

9.5.2.2 Debris Removal

Preparing a site for land reclamation may require the removal of debris from mining, construction, or other operations previously conducted at the site. The extent to which

debris must be removed depends on the post-reclamation

use. For example, if agricultural activities are planned, the

top 60 cm (24 in) should be free of foreign material of

any significant size (Gschwind and Pietz, 1992). If the

site is to be revegetated for erosion control, debris should

be removed from the top 30 cm (12 in) of soil. If an irrigation

hose is used, extensive rock removal will prevent excessive

wear of the hose (Gschwind and Pietz, 1992).

9.5.2.3 Erosion and Surface Runoff Control

Measures

Surface runoff and soil erosion from the reclamation site

should be controlled. These measures may include erosion control blankets, filter fences, straw bales, and

mulch. It may be necessary to construct diversion terraces and/or sedimentation ponds. The local Natural

Resources Conservation Service (formerly the Soil Conservation Service) can be contacted for assistance in

designing erosion and surface runoff control plans. In

addition, see Chapter 13 of this manual.

9.5.3 Methods of Application

Methods for land application of sewage sludge include

surface spreading, incorporation, spray irrigation, and

injection. These methods are discussed in Chapter 14.

9.5.4 Storage

Sewage sludge storage will probably be needed at a

reclamation site. The Part 503 regulation defines storage as the placement of sewage sludge on land on

which the sewage sludge remains for two years or less.

Storage may occur at the treatment works and/or at the

land application site. In general, when liquid sewage

sludge is used, storage is provided at the treatment plant

in digesters, holding tanks, or lagoons. At land application sites where large quantities of liquid sewage sludge

are used, storage lagoons may be built at the site.

If dewatered sewage sludge is used, storage may be

more advantageously located at the land application

site. Small storage areas may also be desirable at the

treatment plant for times of inclement weather or equipment breakdown.

At currently mined sites, it may be necessary to transport and stockpile dewatered sewage sludge at the site

prior to land application while the area is being backfilled

and topsoiled. This would allow large quantities of sewage sludge to be applied in a relatively short period of

time and also allows more efficient use of manpower

and equipment. Some states have specific regulations

concerning sewage sludge stockpiling onsite for short

periods of time. For example, in Pennsylvania, the sewage sludge storage area must be diked to prevent surface water from running into or out of the storage area.

9.6 Scheduling

The timing of sewage sludge application depends on the

climate, soil conditions, and growing season. The Part

503 regulation prohibits bulk sewage sludge application

to flooded, frozen, or snow-covered reclamation sites in

such a way that the sewage sludge enters a wetland or

other surface waters (except as provided in a permit

issued under Section 402 or 404 of the Clean Water

Act). Sewage sludge should not be applied during periods of heavy rainfall because this greatly increases the

chances of surface runoff. Sewage sludge also should

not be applied in periods of prolonged extreme heat or

dry conditions, since considerable amounts of nitrogen

will be lost before the vegetation has a chance to establish itself. If sewage sludge is applied and allowed to dry

on the soil surface, from 20 to 70 percent of the NH4-N

will be volatilized and lost to the atmosphere as NH3.

The exact amount of NH4-N lost will depend on soil,

sewage sludge, and climate conditions (U.S. EPA, 1978).

Sewage sludge applications should be scheduled to

accommodate the growing season of the selected plant

species. If soil conditions are too wet when sewage

sludge is applied, the soil structure may be damaged,

bulk density increased, and infiltration decreased due to

heavy vehicle traffic on the wet soil. This may increase

the possibility of soil erosion and surface runoff. In ad119
dition, the tractors or trucks may experience difficulty

driving on the wet soil.

If the area to receive sewage sludge is covered under

federal or state mining regulations, the sewage sludge

application must be scheduled to comply with the revegetation regulations. For example, in Pennsylvania, mined

land can be seeded in the spring as soon as the ground is

workable, usually early in March, but seeding must terminate by May 15. The late summer seeding season is from

August 1 until September 15. The designer should check

on requirements for his or her locale.

9.7 Determining Sewage Sludge

Application Rates at Reclamation

Sites

9.7.1 General Information

Historically, land application of sewage sludge at reclamation sites generally has involved large applications of

sludge to sufficiently establish vegetation, with rates

sometimes exceeding 200 t/ha and no subsequent applications. Such high application rates almost invariably

exceed agronomic rates for plant nitrogen needs, and can

result in temporary leaching of nitrate into ground water.

The Part 503 rule specifies that, in general, application

of sewage sludge should not exceed the agronomic rate

for N, but that higher rates may be allowed at reclamation sites if approved by the permitting authority. When

determining sewage sludge application rates, it is useful

to draw a general distinction between “reconstructed”

and “abandoned” reclamation sites:

• “Reconstructed” reclamation sites generally include

coal mine reclamation sites that have been or are

being reclaimed according to provisions of the 1977

federal Surface Mining Reclamation and Control Act

(SMCRA), and surface-mine reclamation sites involving non-coal minerals (such as iron and copper) regulated by other federal or state programs that require

a measure of soil reconstruction after the mineral has

been removed. SMCRA requires grading of spoils to

reestablish the approximate original contour of the

land, the saving and replacement of topsoil on all

areas affected by mining, and additional soil reconstruction for prime farmlands. Grading of mine spoils

and replacement of topsoil is also a routine practice at

active surface mine sites involving non-coal minerals.

• “Abandoned” reclamation sites are typically abandoned coal mine sites, especially those involving

acid- or toxic-forming spoil or coal refuse, where disturbance occurred prior to enactment of SMCRA and

natural revegetation has been sparse. Other mine

sites where mining practices or unfavorable overburden chemistry have resulted in poor vegetation establishment also can be considered “abandoned” reclamation sites.

Generally, application of sewage sludge at rates exceeding

plant N requirements is not justified at reconstructed reclamation sites, and procedures for determining sewage

sludge application rates should be the same as those

described in Chapter 7 for agricultural crops or Chapter

8 for forest sites. An exception might be where topsoil

was very thin or missing before mining, such as forest

lands on steep slopes with weakly developed soil horizons (Sopper, 1993).

Large, one-time sewage sludge applications that exceed the agronomic rate for N are most likely to be

justified at abandoned sites, such as abandoned acid

strip mine spoils, where ground-water quality is usually

already severely degraded. At such sites, the long-term

benefits of the large addition of organic matter in the

sewage sludge to the mine spoils for establishing an

improved vegetative cover exceed the short-term effects

of leaching of excess nitrate from the sludge. Section

9.7.2 below describes a procedure for determining application rates at abandoned reclamation sites where

the agronomic rate may not be sufficient to reestablish

vegetation.

9.7.2 Approach for Determining a Single,

Large Application of Sewage Sludge at

a Reclamation Site

The approach for determining the maximum acceptable

one-time application of sewage sludge to a reclamation

site is based on evaluating the effect of N in excess of

plant needs from a large application on soil-water nitrate concentrations. The main steps in this procedure

involve:

1) Determine the maximum allowable application

rate (Smax) (e.g., based on the Part 503 CPLR

limits, see Chapter 3).

2) Perform N budget calculations to determine the

available N in excess of plant needs (using Smax,

as described in Section 9.7.3).

3) Estimate the soil-water nitrate concentrations that

will result from the excess N from a one-time

application at Smax.

4) If soil-water nitrate concentrations from application of Smax are not acceptable, a lower application

rate is set that will not exceed a defined acceptable soil-water nitrate concentration.

Section 9.7.3 provides a design example that illustrates

this process.

120
9.7.3 Design Example for a Single, Large

Sewage Sludge Application at a

Reclamation Site

A five-acre area of abandoned acidic mine spoils (pH

3.9) in Kentucky is to be reclaimed using a single large

application of sewage sludge to provide organic matter

and nutrients required to support establishment of a

mixture of grass and legumes, with a first-year N requirement of 300 kg/ha. Based on appropriate soil tests,

it was determined that agricultural lime application of

12.3 t/ha (5.5 T/ac) is sufficient to raise the soil pH to

6.5. The spoils are slowly permeable (0.2 cm/hr). Net

precipitation infiltrating into the ground is estimated to

be 80 cm (31.5 in), of which 20 percent is estimated to

be lost by evapotranspiration. Depth to ground water is

5 m (16 ft).

The sewage sludge to be applied has undergone anaerobic digestion and has the following characteristics:

• Solids - 4.0 percent

• Organic N - 2.5 percent

• NH4-N - 1.0 percent

• NO3-N - 0 percent

• Total P - 2.0 percent

• Total K - 0.5 percent

• As - 10 mg/kg

• Cd - 10 mg/kg

• Cr - 1,000 mg/kg

• Cu - 3,750 mg/kg

• Pb - 150 mg/kg

• Hg - 2 mg/kg

• Mo - 8 mg/kg

• Ni - 100 mg/kg

• Se - 15 mg/kg

• Zn - 2,000 mg/kg

Step 1. Calculate Maximum Application Based

 on Metal Loading

The cumulative pollutant loading rate for a particular

metal is calculated using the following equation:

Smax = L/Cm (1,000 kg/t) (9-1)

where:

Smax = The total amount of sewage sludge, in

t/ha, that would result in the cumulative

pollutant loading rate limit, L.

L = The Part 503 cumulative pollutant loading rate limit (CPLR) for sewage sludge

in kg/ha (see Chapter 3).

Cm = Concentration, in mg/kg, of the metal of

concern in the sewage sludge being

applied.

The limiting metal in this example is copper, with Smax =

400 t/ha. In reality, most sewage sludges contain lower

copper levels; this higher level is used here to illustrate

an application rate higher than the agronomic rate.

Since sludge applications at 400 t/ha could result in a

high nitrogen impact on ground water during the first two

years of operation, a loading rate of 200 t/ha was selected, which is sufficient for establishing vegetation.

Note that if the copper concentration in the sewage

sludge in this example met Part 503’s “pollutant concentration limit” (as do all the other pollutants listed) rather

than the CPLR limit for copper, cumulative metal loadings would not be required to be tracked (see Chapter

3), and application rates would not be limited by cumulative pollutant loadings (see Chapter 7, Section 7.4.4.3).

Step 2. Determine Excess N Available for 

 Leaching

Available N content of the revised Smax (200 t/ha) is

calculated using the following equation:

Np = S [(NO3) + Kv (NH4) + F(year 0-1) (No)] (10) (9-2)

where:

Np = Plant-available N (from this year’s sewage sludge application only), in kg/ha.

S = Sewage sludge application rate, in dry t/ha.

NO3 = Percent nitrate-N in the sewage sludge,

as percent.

Kv = Volatilization factor, usually set at 0.5

for surface-applied liquid sewage

sludge, or 1.0 for incorporated liquid

sludge and dewatered sludge applied in

any manner.

NH4 = Percent ammonia-N in the sewage

sludge, as percent (e.g., 1% = 1.0).

F(year 0-1)= Mineralization factor for organic N in

the sewage sludge in the first year, expressed as a fraction (e.g., 0.2).

No = Percent organic N in the sewage

sludge, as percent (e.g., 2.5% = 2.5).

Since the sludge is to be surface applied, Kv = 0.5.

Np1 = 200 [(0.0) + (0.5)(1.0) + (0.2)(2.5)] (10)

 = 2,000 kg/ha

Available N in the second year after the one-time application is simply the amount mineralized from the initial

application, using the following equation:

121
Nm = (S) (Km) (No) (9-3)

where:

Nm = Quantity of No mineralized in the year

under consideration, in kg/ha.

S = Sewage sludge application rate, in dry

t/ha.

Km = Mineralization factor for the year under

consideration, expressed as a fraction.

No = Percent organic N originally present in

the sewage sludge, as percent (e.g.,

2.5% = 2.5).

In this example, for illustrative purposes, Km2 = 0.80 and

Km3 = 0.36 in the second and third years respectively for

anaerobic sludge. Thus:

Nm2 = (200) (0.80) (2.5)

 = 400 kg/ha

Nm3 = (200) (0.36) (2.5)

 = 180 kg/ha

A simplified N budget for the Smax sludge application for

the first three years after application is as follows, with

Nr representing plant uptake (300 kg/ha):

Year 1: Nexcess = Np1 - Nr = 2,000 - 300 = 1,700 kg/ha

Year 2: Nexcess = Nm2 - Nr = 400 - 300 = 100 kg/ha

Year 3: Nexcess = Nm3 - Nr = 100 - 300 = 0 kg/ha

In the first year, available N is more than 6 times the

plant uptake, and by the second year is slightly more

than plant uptake. In the third year, mineralized N is less

than potential plant uptake. Consequently, with a one-time

large application of sewage sludge, leaching of nitrate

can be expected during the first year, with minimal

leaching in the second year and no leaching in the third

year. These N budget calculations have been simplified

for this illustrative example; the more detailed annual N

budget calculations contained in the Worksheets in

Chapter 7 can also be used.

Step 3. Calculation of Potential Nitrate

 Leaching into Ground Water

It is possible to make a conservative estimate of the

quantity of nitrates potentially leaching into the ground

water by calculating the maximum potential concentration of excess nitrates percolating from the site into the

underlying aquifer. This is done by assuming that all N

in excess of plant needs is converted to nitrates, and that

no dilution of percolate occurs in existing ground water.

Assume annual net infiltration of precipitation, PI =

80 cm.

Assume evapotranspiration losses, ET = 20% =

0.20.

If all of the excess nitrogen in the sludge applied is

mobile (an unlikely and very conservative assumption),

the concentration of nitrate in the percolate is calculated

using the following equation:

Soil Water NO3, mg/L =

 

 (Nexcess, kg/ha) (106

 mg/kg) (1,000 cm3/L)

(108

 cm2/ha) (PI, cm) (1−ET)

 = (1,700 kg/ha) (106 mg/kg) (1,000 cm3

/L)

(108

 cm2/ha) (80 cm) (1−0.20)

 = 266 mg/L

Repeating the calculation for the excess N in the

second year indicates a maximum NO3 concentration

of 16 mg/L. By the third year, the site would meet the

nitrate drinking water MCL of 10 mg/L because no excess N exists.

If the potential concentration of nitrate-N in the percolate

that exceeds the MCL during the first two years after

sewage sludge application is unacceptable to the regulatory agency, even though by the third year leaching

effects are minimal, and if there is no extraction of

potable water from the aquifer, maximum sludge application rates can be calculated based on a maximum

acceptable level of NO3 in percolating soil water.

Additional information on the design of mine land reclamation projects using municipal sewage sludge can be

found in the Manual for the Revegetation of Mine Lands

in Eastern United States Using Municipal Biosolids

(Sopper, 1994).

9.8 References

When an NTIS number is cited in a reference, that

document is available from:

 National Technical Information Service

 5285 Port Royal Road

 Springfield, VA 22161

 703-487-4650

Bennett, O.L., E.L. Mathias, W.H. Arminger, and J.N. Jones, Jr. 1978.

Plant materials and their requirements for growth in humid regions. In: Schaller, F.W., and P. Sutton, eds. Reclamation of drastically disturbed lands. American Society of Agronomy, Madison,

WI. pp. 285-306.

122
Berg, W.A. 1978. Limitations in the use of soil tests on drastically

disturbed lands. In: Schaller, F.W., and P. Sutton, eds. Reclamation

of drastically disturbed lands. American Society of Agronomy,

Madison, WI. pp. 653-664.

Berry, C.R. 1982. Sewage sludge aids reclamation of disturbed forest

land in the southeast. In: Sopper, W.E., E.M. Seaker, and R.K.

Bastian, eds. Land reclamation and biomass production with municipal wastewater and sludge. Pennsylvania State University

Press, University Park, PA. pp. 307-316.

Fed. Reg. 1982. Surface coal mining and reclamation permanent

program regulations: revegetation. March 23.

Gschwind, J., and R. Pietz. 1992. Application of municipal sewage

sludge to soil reclamation sites. In: Lue-Hing, C., D. Zenz, and R.

Kuchenrither, eds. Municipal sludge management: Processing,

utilization, and disposal. Water Quality Management Library, Vol.

4. Lancaster, PA: Technomic Publishing Company. pp. 455-478.

Jacobs, L., S. Carr, S. Bohm, S., and J. Stukenberg. 1993. Document

long-term experience of biosolids land application programs. Project 91-ISP-4, Water Environment Research Foundation, Alexandria, VA.

Pennsylvania Department of Environmental Resources. 1988. Land

application of sewage sludge. In: Rules in the Pennsylvania Code,

Title 25, Chapter 275.

Peterson, J., C. Lue-Hing, J. Gschwind, R. Pietz, and D. Zenz. 1982.

Metropolitan Chicago’s Fulton County sludge utilization program.

In: Sopper, W., E. Seaker, and R. Bastian, eds. Land reclamation

and biomass product with municipal wastewater and sludge. University Park, PA: Pennsylvania State University Press. Cited in

Gschwind and Pietz, 1992.

Pietz, R., J. Peterson, T. Hinesly, E. Ziegler, K. Redborg, and C.

Lue-Hing. 1982. Sewage sludge application to calcareous stripmine spoil: I, Effect on corn yields and N, P, Ca, and Mg compositions. J. Environ. Quality 18:685-689. Cited in Gschwind and

Pietz, 1992.

Rafaill, B.L., and W.G. Vogel. 1978. A guide for vegetating surfacemined lands for wildlife in eastern Kentucky and West Virginia.

FWS/OBS-78-84. U.S. Fish and Wildlife Service, Washington, DC.

Sopper, W. 1994. Manual for the revegetation of mine lands in the

eastern United States using municipal biosolids. Morgantown, WV:

West Virginia University, National Mine Land Reclamation Center.

Sopper, W. 1993. Municipal sludge use in land reclamation. Boca

Raton, FL: Lewis Publishers.

Sopper, W., and S. Kerr. 1982. Mine land reclamation with municipal

sludge—Pennsylvania demonstration program. In: Sopper, W.E.,

E.M. Seaker, and R.K. Bastian, eds. Land reclamation and

biomass product with municipal wastewater and sludge. University

Park, PA: Pennsylvania State University Press. pp. 55-74.

Sopper, W., S. Kerr, E. Seaker, W. Pounds, and D. Murray. 1981. The

Pennsylvania program for using municipal sludge for mine land

reclamation. In: Proceedings of the Symposium on Surface Mining

Hydrology, Sedimentology, and Reclamation. University of Kentucky, Lexington, KY. pp. 283-290.

Sopper, W., and E. Seaker. 1983. A guide for revegetation of mined

land in the eastern United States using municipal sludge. University Park, PA: Pennsylvania State University Institute for Research

on Land and Water Resources.

U.S. Department of Interior. 1979. Permanent regulatory program

implementing Section 501(b) of the Surface Mining Control and

Reclamation Act of 1977; Final Environmental Statement. OSMEIS1. Washington, DC.

U.S. EPA. 1978. Sludge treatment and disposal, Vol. 2. Center for

Environmental Research Information, Cincinnati, OH. EPA/625/4-

78/012 (NTIS PB-299 593).

U.S. Soil Conservation Service. 1977. The status of land disturbed by

surface mining in the United States. SCS-TP-158. Washington, DC.

123
Chapter 10

Land Application at Public Contact Sites, Lawns, and Home Gardens

10.1 General

In addition to land application at agricultural, forest, and

reclamation sites, sewage sludge and domestic septage

can be land applied to lawns and home gardens as well

as “public contact sites.” The Part 503 regulation defines

public contact sites as land with a high potential for

contact by the public, such as parks, ball fields, cemeteries, plant nurseries, turf farms, and golf courses. In

many cases, sewage sludge is applied to these types of

sites from bags or other containers1

 that are sold or

given away (hereafter referred to as “bagged” sewage

sludge), although sewage sludge also can be land applied to these types of sites in bulk form. Often the

sewage sludge used at these sites is processed and

marketed by municipalities or private firms as a brandname fertilizer and/or soil conditioning product. Designing land application programs geared toward public

contact sites, lawns, and home gardens may be particularly useful for municipalities with limited land available

(e.g., highly populated areas with few agricultural, forest, or reclamation sites available for sewage sludge

application).

This chapter discusses how the Part 503 requirements

pertain to land application of sewage sludge and domestic septage at public contact sites, lawns, and home

gardens (Section 10.2). Important factors to consider in

designing a marketing program for sewage sludge to be

land applied at public contact sites, lawns, and home

gardens are discussed in Section 10.3.

10.2 Part 503 Requirements

Many of the strictest requirements in Part 503 must be

met for sewage sludge or domestic septage that is land

applied to public contact sites, lawns, and home gardens (e.g., Class A pathogen reduction; for metals, annual pollutant loading rate limits for bagged sewage

sludge or pollutant concentration limits for bulk sewage

sludge, see Chapter 3). Domestic septage applied to

public contact sites, lawns, or home gardens must meet

the same requirements as bulk sewage sludge that is

land applied, although less burdensome requirements

pertain to domestic septage applied to other types of

land (agricultural, forest, or reclamation sites), as described in Chapter 11. The stringent requirements are

specified for sewage sludge that is land applied to public

contact sites, lawns, and home gardens because of the

high potential for human contact with sewage sludge at

these types of sites and because it is not feasible to

impose site restrictions when sewage sludge is sold or

given away in bags or other containers for application to

the land. The sewage sludge used in this manner must

meet the requirements for metals, pathogens, vector

attraction reduction, management practices, and other

requirements specified in Part 503 for application to

these types of sites, as discussed in Chapter 3.

The effects of the Part 503 regulation on current sewage

sludge land application programs depends on the quality of the sewage sludge. If a sewage sludge meets

certain Part 503 requirements, the sewage sludge can

be considered “exceptional quality” (EQ), as discussed

in Chapter 3. EQ sewage sludge can be applied as

freely as any other fertilizer or soil amendment to any

type of land. If EQ sewage sludge requirements are met,

current land application operations, including those

with already successful marketing programs for sewage sludge (see Section 10.3), may continue with a

minimum of additional regulatory requirements. For sewage sludge preparers2

 who have difficulty meeting the Part

503 requirements for public contact sites, lawns, or home

gardens, operational changes may need to be implemented to further reduce pathogen or metal levels for

land application at these types of sites. The types of

sewage sludge treatment and preparation that can

achieve EQ-quality sewage sludge (e.g., heat drying)

are discussed in Chapter 3.

10.3 Marketing of Sewage Sludge

After processing to achieve Part 503 requirements, sewage sludge that is to be land applied at public contact

1 The Part 503 regulation defines “other containers” as open or closed

receptacles, such as buckets, boxes, carton, or vehicles, with a load

capacity of 1 metric ton or less.

2 The Part 503 regulation defines a person who prepares sewage

sludge as either the person who generates sewage sludge during

the treatment of domestic sewage in a treatment works or the person

who derives a material from sewage sludge.

125
sites, lawns, and home gardens often is marketed to

distributors or end users (e.g., landscapers, home gardeners), frequently as bagged sewage sludge. Designing

a marketing program for sewage sludge has some similarities to marketing any commercial product, including:

• Maintaining the “high quality” of the product

• Ensuring the product is readily available

• Developing and maintaining product demand

• Offering competitive pricing

Two marketing factors particularly relevant to sewage

sludge are:

• Maintaining good public relations

• Ensuring that the operations are acceptable to the

community

Having a diversified range of products may be useful. In

the case of sewage sludge, this might include producing

a Class B bulk sewage sludge for agricultural, forest,

and reclamation sites, and a Class A bagged sewage

sludge product, such as compost, for use by landscapers,

public works departments, and the public.

10.3.1 Developing Product Demand

To create and maintain product demand, many municipalities or private firms use a trade name to enhance

marketability, such as Milorganite, a heat-dried, bagged

sewage sludge produced by the city of Milwaukee, Wisconsin, and Philorganic, a composted sewage sludge

produced by the city of Philadelphia, Pennsylvania.

Other cities that produce heat-dried sewage sludge include Chicago, Houston, Atlanta, Tampa Bay, and New

York City. Municipalities that produce composted sewage sludge include the District of Columbia, Kittery

(Maine), Denver, Missoula (Montana), and Los Angeles.

Some municipalities also conduct market surveys to

determine who would be interested in purchasing their

product; use agricultural professionals as sales agents;

advertise in professional journals and the mass media;

and contract with an intermediary for distribution.

The wastewater treatment plant or other preparer of

sewage sludge may be able to increase marketability by

offering the customer various important “services,” such

as (Warburton, 1992):

• Storing the user’s purchased sewage sludge at the

wastewater treatment plant (in accordance with Part

503 provisions).

• Providing the user with results of nutrient, pollutant,

and any ground-water, surface water, or plant tissue

sampling tests.

• Offering dependable transport to the land application

site at times suitable for land application.

• Assisting in obtaining required permits.

• Performing reliable inventory management, so that

the “product” is always available when needed.

In many cases, marketing of sewage sludge can include

promoting the concept of reuse/recycling. For example, the City of Los Angeles now reuses 100% of its

300 dT/day of sludge through agricultural land application (at various sites), as soil cover at a landfill, and

composting. Los Angeles has implemented several innovative sewage sludge marketing programs. One is the

“Full Cycle Recycle” composting program, which includes public education for LA’s “Topgro” soil amendment/compost product. Topgro is produced from city

wastes (sewage sludge and/or yard trimmings), processed locally, and marketed as “home grown” to local

nurseries, retailers, and City agencies in bulk or bag at

competitive prices. Another LA sewage sludge marketing program is a cooperative composting project between the city’s Department of Public Works and

Department of Recreation and Parks, in which sewage

sludge, zoo manure, and plant wastes are processed

and used as compost at city parks; the composting

facility also serves as an educational center for the

public (Molyneux et al., 1992).

10.3.2 Marketing Cost Considerations

The costs of a sewage sludge marketing program may

be high relative to costs of direct land application. Major

cost factors include:

• Dewatering the sewage sludge.

• Composting, heat drying, or other processes to

achieve adequate pathogen reduction and vector

attraction reduction.

• Market development.

• Transportation.

Dewatering and other processing can involve significant

capital expenditures. Some generators/preparers of

sewage sludge may choose to contract out some processing technologies, which can be done through competitive bidding between vendors that produce similar

products (e.g., a heat-dried product, compost, certain

alkaline stabilization processes that meet Part 503

Class A pathogen reduction requirements) to reduce

program costs (Warburton, 1992). The City of Los Angeles has reduced its sludge management program

costs by an average of $3 per dry ton as a result

of improved management, decreased transportation

times, price rebates, volume discounts, and minimizing

truck loading times (Molyneux et al., 1992).

A marketing program for sewage sludge always should

include examination of the costs of transporting the sewage sludge. Transportation costs may include conveying

126
the sludge from the wastewater treatment plant to the

processing center, transport of bulking materials for

composting, and distribution of the finished sewage

sludge product. Although extending the geographical

marketing area would increase shipping costs, it may be

worthwhile if it is likely that potential buyers in the extended area are willing to pay a higher price for the

product.

Some municipalities charge the distributor or end user

for the use of a sewage sludge product, as shown in

Table 10-1. The table indicates that from 38% to 60% of

POTWs sell their sludge at rates ranging from $4 to $6 per

cubic yard or $34 to $63 per ton. In some cases, the

municipality may not make a “profit” from selling sewage

sludge, but the sales can reduce operating costs for

overall sewage sludge management. In other cases, the

sewage sludge generator or preparer pays the landowner or person responsible for land applying sewage

sludge if payment results in lower sewage sludge management costs.

In some localities, demand has exceeded supply for

marketed sewage sludge. In other areas, marketed sewage sludge programs have failed because of poor or

inconsistent product quality or operational practices unacceptable to the community. Demand for sewage

sludge for land application tends to be seasonal, peaking in the spring and fall in areas with four-season

climates. In areas with mild climates year-round, a constant market can be developed.

10.4 References

Molyneux, S., R. Fabrikant, and C. Peot. 1992. Waste to resource:

The dynamics of a sludge management program. In: Proceedings

of the future direction of municipal sludge (biosolids) management: Where we are and where we’re going, Vol. I, Portland, OR.

Water Environment Federation, Alexandria, VA.

U.S. EPA. 1990. National sewage sludge survey: Availability of information and data, and anticipated impacts on proposed regulations. Fed. Reg. 58:18.

Warburton, J. 1992. So, you’re convinced sludge is a valuable resource—Then market it like a perishable commodity. In: Proceedings of the future direction of municipal sludge (biosolids)

management: where we are and where we’re going, Vol. 1, Portland, OR. Water Environment Federation, Alexandria, VA.

Table 10-1. Percent of POTWs Selling Sewage Sludge and

Mean Price of Sewage Sludge Sold (Adapted

From U.S. EPA, 1990)

Reported Flow

Rate Groupa % of POTWs

That Sellb Price PerTonc Price PerCubic Ydc

1 60.0% $63 $5 

2 71.4 34 6

3 42.1 - 4

4 37.5 - 6

a

 Flow rate group 1 = >100 MGD; 2 = >10-100 MGD; 3 = >1-10 MGD;

4 = 0-1 MGD. b

 Percents based on a total of 46 POTWs.

c

 50% of the POTWs who reported that they sold sewage sludge

provided price data.

127
Chapter 11

Land Application of Domestic Septage

11.1 General

Land application of domestic septage is an economical

and environmentally sound practice used by many rural

communities. Like land application programs for other

types of sewage sludge, a properly managed land application program for domestic septage can benefit from

the reuse of the organic matter and nutrients in the

domestic septage without adversely affecting public

health. Sometimes, however, finding suitable sites,

overcoming local opposition, or meeting regulatory requirements may be difficult. The Part 503 regulation

governing the use or disposal of sewage sludge, promulgated in February 1993, includes simplified requirements for the land application of domestic septage

(compared to more extensive requirements for other

types of sewage sludge generated by a wastewater

treatment plant). While the Part 503 rule provides minimum guidelines for state programs, individual state

regulations may be more stringent.

The Part 503 regulation includes minimum requirements

for the application of domestic septage to land used

infrequently by the general public, such as agricultural

fields, forest land, and reclamation sites.

For land application of domestic septage to land where

public exposure potential is high, however (i.e., public

contact sites or home lawns and gardens), the same

Part 503 requirements as those for bulk sewage sludge

applied to the land must be met (i.e., general requirements, pollutant limits, pathogen and vector attraction

reduction requirements, management practices, frequency of monitoring requirements, and recordkeeping

and reporting requirements) (U.S. EPA, 1994a). See

Chapter 3 for a discussion of each of these provisions

of the Part 503 rule.

The remainder of this chapter focuses on the land application of domestic septage to agricultural land, forests, or reclamation sites. For additional information on

applications to these types of land, see Domestic Septage Regulatory Guidance: A Guide To Part 503 (U.S.

EPA, 1993).

11.1.1 Definition of Domestic Septage

Domestic septage is defined in the Part 503 regulation

as the liquid or solid material removed from a septic

tank, cesspool, portable toilet, Type III marine sanitation

device, or a similar system that receives only domestic

sewage (water and wastewater from humans or household operations that is discharged to or otherwise enters

a treatment works). Domestic sewage generally includes wastes derived from the toilet, bath and shower,

sink, garbage disposal, dishwasher, and washing machine. Domestic septage may include household septage as well as septage from establishments such as

schools, restaurants, and motels, as long as this septage does not contain other types of wastes than those

listed above.

Domestic septage characteristics are presented in Table 11-1 (conventional wastewater parameters and nutrients) and Table 11-2 (metals and organics) (U.S.

EPA, 1994a).

Table 11-1. Characteristics of Domestic Septage:

Conventional Parameters (U.S. EPA, 1994b)

Concentration (mg/L)

Parameter Average Minimum Maximum

Total solids 34,106 1,132 130,475

Total volatile solids 23,100 353 71,402

Total suspended solids 12,862 310 93,378

Volatile suspended solids 9,027 95 51,500

Biochemical oxygen demand 6,480 440 78,600

Chemical oxygen demand 31,900 1,500 703,000

Total Kjeldahl nitrogen 588 66 1,060

Ammonia nitrogen 97 3 116

Total phosphorus 210 20 760

Alkalinity 970 522 4,190

Grease 5,600 208 23,368

pH — 1.5 12.6

129
11.1.2 Domestic Septage Versus

Industrial/Commercial Septage

The specific definition of domestic septage in the Part 503

regulation does not include many materials that are often

called septage by industry. Commercial and industrial septage are not considered domestic septage. The factor that

differentiates commercial and industrial septage from domestic septage is the type of waste being produced (a treatment

works, e.g., a septic tank, receiving domestic sewage), rather

than the type of establishment generating the waste. For

example, sanitation waste and residues from food and normal dish cleaning from a restaurant are considered domestic

sewage, whereas grease trap wastes from a restaurant are

classified as commercial septage. If restaurant grease trap

wastes are included with domestic septage in a truckload,

then the whole truckload is not covered by the Part 503

regulation (U.S. EPA, 1993). Instead, commercial and

industrial septage and mixtures of these septages with

domestic septage are regulated under 40 CFR Part 257

if the septage is used or disposed on land. Industrial and

commercial septage containing toxic compounds or

heavy metals require special handling, treatment, and

disposal methods; a discussion of these methods is

beyond the scope of this manual.

11.2 Regulatory Requirements for Land

Application of Domestic Septage

11.2.1 Determining Annual Application Rates

for Domestic Septage at Agricultural

Land, Forests, or Reclamation Sites

Federal requirements that have been established under

Part 503 for land application of domestic septage are

discussed in Chapter 3. According to the Part 503 regulation, the maximum volume of domestic septage that

may be applied to agricultural land, forest land, or a

reclamation site during a 365-day period depends on the

amount of nitrogen required by the crop for the planned

crop yield. The maximum volume for domestic septage

is calculated by the following formula:

AAR = N

0.0026

Where:

AAR = Annual application rate in gallons per

acre per 365 day period.

N = Amount of nitrogen in pounds per acre

per 365 day period needed by the crop

or vegetation grown on the land.

For example, if 100 pounds of nitrogen per acre is

required to grow a 100 bushel per acre crop of corn, then

the AAR of domestic septage is 38,500 gallons per acre

(U.S. EPA, 1993):

AAR = 100 lbs/acre/year

0.0026 = 38,500 gallons/acre/year

Application rate requirements pertain to each site where

domestic septage is applied and must be adjusted to the

nitrogen requirement for the crop being grown (U.S. EPA,

1993). Nitrogen requirements of a crop depend on expected

yield, soil conditions, and other factors such as temperature,

rainfall, and length of growing seasons. Local agricultural

extension agents should be contacted to determine the

appropriate nitrogen requirements for use in the above

equation for calculation of the application rate.

Table 11-3 outlines typical nitrogen requirements of various crops and corresponding domestic septage application rates (U.S. EPA, 1993). These values are listed as

general guidance only; more specific information on the

Table 11-2. Characteristics of Domestic Septage: Metals and

Organics (U.S. EPA, 1994b) 

Concentration (mg/L)

Parameter Average Minimum Maximum

Metals

Iron 39.3 0.2 2740

Zinc 9.97 < 0.001 444 

Manganese 6.09 0.55 17.1

Barium 5.76 0.002 202 

Copper 4.84 0.01 261 

Lead 1.21 < 0.025 118 

Nickel 0.526 0.01 37

Chromium (total) 0.49 0.01 34

Cyanide 0.469 0.001 1.53 

Cobalt 0.406 < 0.003 3.45 

Arsenic 0.141 0 3.5 

Silver 0.099 < 0.003 5

Cadmium 0.097 0.005 8.1

Tin 0.076 < 0.015 1

Mercury 0.005 0.0001 0.742

Organics

Methyl alcohol 15.8 1 396 

Isopropyl alcohol 14.1 1 391 

Acetone 10.6 0 210 

Methyl ethyl ketone 3.65 1 240 

Toluene 0.17 .005 1.95

Methylene chloride 0.101 0.005 2.2 

Ethylbenzene 0.067 0.005 1.7 

Benzene 0.062 0.005 3.1

Xylene 0.051 0.005 0.72

130
amount of nitrogen required for the expected crop yield

under local soil and climatic conditions should be obtained from a qualified, knowledgeable person, such as

a local agricultural extension agent. The crop nitrogen

requirement is then used in the annual application rate

formula to calculate the gallons per acre of domestic septage that can be applied.

While not required by the Part 503 rule, it is important

that the septic tank pumper inform the landowner or

lease holder of the land application site regarding how

much of the crop’s nitrogen requirement was added by

the applied domestic septage. This information will allow

the land owner to determine how much additional nitrogen, if any, in the form of chemical fertilizer will need to

be applied (U.S. EPA, 1993). The pumper should also

inform the landowner/leaser of any site restrictions.

11.2.1.1 Protection of Ground Water from

Nitrogen Contamination

The primary reason for requiring the annual rate calculation is to prevent the over-application of nitrogen in excess

of crop needs and the potential movement of nitrogen

through soil to ground water. The annual application rate

formula was derived using assumptions that facilitate

land application of domestic septage. For example, fractional availability of nitrogen from land-applied domestic

septage was assumed over a 3-year period to obtain the

0.0026 factor in the application formula. Also, in deriving

the formula, domestic septage was assumed to contain

313 mg/l per year available nitrogen (in year three and

thereafter) (U.S. EPA, 1992a).

Domestic septage from portable chemical toilet and type

III marine sanitation device wastes can contain 4 to 6

times more total nitrogen than was assumed to derive

the annual application rate formula, however (U.S. EPA,

1993). While not required by the Part 503 regulation, it

is recommended that land appliers consider reducing

the volume applied per acre of such high nitrogen-containing domestic septage (U.S. EPA, 1993). For example, if the land owner is expecting to grow a 100-bushel

per acre corn crop and the domestic septage contains

6 times more total nitrogen, the gallons applied should

be reduced 6-fold (from 38,500 to about 6,400 gallons).

For additional guidance on avoiding nitrogen contamination of ground water when land applying domestic septage

with a high nitrogen content or dewatered domestic septage, see Domestic Septage Regulatory Guidance: A

Guide to the EPA 503 Rule (U.S. EPA, 1993).

11.2.2 Pathogen Reduction Requirements

Domestic septage must be managed so that pathogens

(disease-causing organisms) are appropriately reduced.

The Part 503 regulation offers two alternatives to meet

this requirement. Pathogen reduction alternative 1 (no

treatment) and restrictions are presented in Figure 11-1

(U.S. EPA, 1993); the requirements of pathogen reduction alternative 2 (with treatment) are listed in Figure

11-2 (U.S. EPA, 1993). Both of the pathogen reduction

alternatives impose crop harvesting restrictions. Site

access controls and grazing restrictions, however, are

also required when the domestic septage is not treated

(alternative 1 only). Certification that the Part 503 pathogen reduction requirement has been met is also required

of the domestic septage land applier, as discussed in

Section 11.2.4 below. Chapter 3 discusses the pathogen

reduction requirements of Part 503 in greater detail.

11.2.3 Vector Attraction Reduction

Requirements

For application of domestic septage to agricultural land,

forests, or reclamation sites, the Part 503 regulation requires that one of the following three options be implemented to reduce vector attraction (U.S. EPA, 1994b):

• Subsurface injection.

• Incorporation (surface application followed by plowing within 6 hrs).

• Alkali stabilization.

Table 11-3. Typical Crop Nitrogen Requirements and

Corresponding Domestic Septage Application

Rates (U.S. EPA, 1993)

Expected

Yield

(bushel/acre/

year)

Nitrogen 

Requirement

(lb N/acre/

year)1

Annual

Application

Rate

(gallons/acre/

year)

Corn 100 100 38,500

Oats 90 60 23,000

Barley 70 60 23,000

Grass & Hay 4 tons/acre 200 77,000

Sorghum 60 60 23,000

Peanuts 40 30 11,500

Wheat 70 105 40,400

Wheat 150 250 96,100

Soybeans 40 30 11,500

Cotton 1 bale/acre 50 19,200

Cotton 1.5 bales/acre 90 35,000

1

 These figures are very general and are provided for illustration

purposes. They should not be used to determine your actual application rate. Crop fertilization requirements vary greatly with soil type.

Expected yields and climatic conditions are also important factors

in determining the appropriate volume of domestic septage to apply

to a particular field. Different amounts of nutrients can be required

by the same crop grown in different parts of the country. To get more

specific information on crop fertilization needs specific to your location, contact local agricultural extension agents.

131
For detailed information on subsurface injection and

incorporation practices at land application sites, see

Chapter 14.

Alkali stabilization of domestic septage involves raising

its pH. Vector attraction is reduced if the pH is raised to

at least 12 through alkali addition and maintained at 12

or higher for 30 minutes without adding more alkali.

When this option is used, every container of domestic

septage must be monitored to demonstrate that it meets

the requirement (U.S. EPA, 1992b). When this is done,

the treatment component of alternative 1 for pathogen

reduction, discussed above, also is met. This vector

attraction reduction requirement is slightly less stringent

than the alkali addition method required by Part 503 for

other types of sewage sludge. This option addresses the

practicalities of using or disposing domestic septage,

which is typically treated by lime addition to the domestic

septage hauling truck (see Section 11.3). The treated

septage is typically applied to the land shortly after lime

addition. During this very short time interval, the pH is

unlikely to fall to a level at which vector attraction could

occur (U.S. EPA, 1992b).

If a land applier of domestic septage chooses pathogen

reduction alternative 1 (see Figure 11-1), which involves

land application of domestic septage without additional

treatment, the Part 503 rule also requires that one of the

first two vector attraction reduction options listed in Table

11-3 be met (U.S. EPA, 1993). If a land applier chooses

pathogen reduction alternative 2 (pH treatment as described in Figure 11-2), he or she must meet the requirements of the third vector attraction reduction option

shown in Figure 11-3 (U.S. EPA, 1993).

11.2.4 Certification Requirements for

Pathogen and Vector Attraction

Reduction

The land applier of domestic septage must sign a certification that the pathogen and vector attraction reduction

requirements of the Part 503 regulation have been met.

The required certification is shown in Figure 11-4. The

certification includes a statement by the land applier that

his or her employees, if any, are qualified and capable

of gathering the needed information and performing the

necessary tasks so that the required pathogen and vector attraction reduction requirements are met. A person

is qualified if he or she has been sufficiently trained to

do their job correctly.

Domestic septage is land applied without treatment, and the

following restrictions must be observed:

Crop Restrictions:

• Food crops with harvested parts that touch the domestic

septage/soil mixture and are totally above ground shall not

be harvested for 14 months after application of domestic

septage.

• Food crops with harvested parts below the surface of the

land shall not be harvested for either (1) 20 months after

application if domestic septage remains on the land

surface for 4 months or longer, or (2) 38 months after

application if domestic septage remains on the land

surface for less than 4 months, prior to incorporation into

the soil.

• Feed, fiber, and food crops shall not be harvested for 30

days after application of the domestic septage.

• Turf grown on land where domestic septage is applied

shall not be harvested for one year after application of the

domestic septage when the harvested turf is placed on

either a lawn or land with a high potential for public

exposure, unless otherwise specified by the permitting

authority.

Grazing Restrictions:

• Animals shall not be allowed to graze on the land for 30

days after application of domestic septage.

Site Restrictions:

• Public access to land with a low potential for public

exposure shall be restricted for 30 days after application of

domestic septage. Examples of restricted access include

remoteness of site, posting with no trespassing signs,

and/or simple fencing.

Figure 11-1. Part 503 pathogen reduction Alternative 1 for domestic septage (without additional treatment) applied to agricultural land, forests, or reclamation

sites (U.S. EPA, 1993).

The pH of the domestic septage is raised to 12 or higher by

the addition of alkali material and, without adding more

alkali, the pH remains at 12 or higher for 30 minutes prior to

being land applied. In addition, the following restrictions

must be observed.

Crop Restrictions:

• Food crops with harvested parts that touch the domestic

septage/soil mixture and are totally above ground shall not

be harvested for 14 months after application of domestic

septage.

• Food crops with harvested parts below the surface of the

land shall not be harvested for either (1) 20 months after

application if domestic septage remains on the land

surface for 4 months or longer, or (2) 38 months after

application if domestic septage remains on the land

surface for less than 4 months, prior to incorporation into

the soil.

• Feed, fiber, and food crops shall not be harvested for 30

days after application of the domestic septage.

Grazing Restrictions: None

Site Restrictions: None

Figure 11-2. Part 503 pathogen reduction Alternative 2 for domestic septage (with pH treatment) applied to agricultural land, forests, or reclamation sites (U.S.

EPA 1993).

132
11.2.5 Restrictions on Crop Harvesting,

Animal Grazing, and Site Access

As discussed above, the Part 503 regulation for domestic septage application to agricultural land, forests, or

reclamation sites includes various restrictions on the

crops harvested and animals grazed on the site, as well

as access to the site by the public. The requirements

are less restrictive if the domestic septage has been

alkali stabilized. Figures 11-1 and 11-2 summarize crop,

grazing, and public access restrictions for untreated

and alkali-stabilized domestic septage, respectively

(U.S. EPA, 1993). It is recommended that land appliers

of domestic septage inform the owner/operator of the

land where the domestic septage has been applied

about these crop harvesting and site access restriction

requirements.

For more detailed information, see EPA’s Domestic

Septage Regulatory Guidance (U.S. EPA, 1993) and 40

CFR Part 503. It is important to note that state regulations may differ and be more restrictive than the requirements outlined in Figures 11-1 and 11-2.

11.2.6 Recordkeeping and Reporting

Records must be kept by a land applier of domestic septage for five years after any application of domestic septage to a site, but Part 503 does not require land appliers

of domestic septage to report this information. These required records might be requested for review at any time

by the permitting or enforcement authority (U.S. EPA,

1993). The retained records must include the information shown in Figure 11-5 and a written certification (see

Figure 11-4). EPA’s Domestic Septage Regulatory Guidance (U.S. EPA, 1993) contains examples of ways to

organize record keeping for sites where domestic septage is land applied.

Vector Attraction Reduction Option 1: 

Injection

Domestic septage shall be injected below the surface of the

land, AND no significant amount of the domestic septage

shall be present on the land surface within one hour after

the domestic septage is injected;

or

Vector Attraction Reduction Option 2: 

Incorporation

Domestic septage applied to the land surface shall be

incorporated into the soil surface plow layer within six (6)

hours after application;

or

Vector Attraction Reduction Option 3:

pH Adjustment

The pH of domestic septage shall be raised to 12 or higher

by addition of alkali material and, without the addition of

more alkali material, shall remain at 12 or higher for 30

minutes.

Figure 11-3. Part 503 vector attraction reduction options for

domestic septage applied to agricultural land, forests, or reclamation sites (U.S. EPA, 1993).

 Certificationa

I certify under penalty of law that the pathogen

requirements in [insert pathogen reduction alternative 1 or 2] and the vector attraction reduction

requirements in [insert vector reduction alternative

1, 2, or 3] have/have not [circle one] been met.

This determination has been made under my direction and supervision in accordance with the

system designed to ensure that qualified personnel properly gather and evaluate the information

used to determine that the pathogen requirements

and the vector attraction reduction requirements

have been met. I am aware that there are significant penalties for false certification, including the

possibility of fine and imprisonment.

 Signed:

 (to be signed by the person designated 

 as responsible in the firm that applies 

 domestic septage)

a

 EPA is proposing changes in the certification language.

Figure 11-4. Certification of pathogen reduction and vector attraction requirements (U.S. EPA, 1994b).

• The location of the site where domestic septage is applied

(either the street address, or the longitude and latitude of

the site, available from U.S. Geological Survey maps).

• The number of acres to which domestic septage is applied

at each site.

• The date and time of each domestic septage application.

• The nitrogen requirement for the crop or vegetation grown

on each site during the year. Also, while not required,

indicating the expected crop yield would help establish the

nitrogen requirement.

• The rate (in gallons per acre) at which domestic septage is

applied to the site during the specified 365-day period.

• The certification shown in Figure 11-4.

• A description of how the pathogen requirements are met

for each volume of domestic septage that is land applied.

• A description of how the vector attraction reduction

requirement is met for each volume of domestic septage

that is land applied.

Figure 11-5. Part 503 5-year recordkeeping requirements (U.S.

EPA, 1993).

133
11.2.7 Part 503 Required Management

Practices

Certain management practices for the land application

of all types of sewage sludge, including domestic septage, are included in Part 503. These management practices require that the land application of sewage sludge

and domestic septage does not adversely affect endangered or threatened species; does not take place during

flooded, frozen or snow-covered conditions; and does

not occur within 33 ft (10 m) of wetlands or surface

waters (U.S. EPA, 1994b). For additional information on

these management practices, see Chapter 3.

11.2.8 State Requirements for Domestic

Septage

The Part 503 regulation sets minimum requirements for

land application of domestic septage that must be met in

all states. States may, however, adopt (or continue to

use) regulations that are more stringent than the federal

rule.

State regulations for domestic septage use or disposal

vary widely. In most cases, states require a hauler to

submit for approval use or disposal plans for domestic

septage. Most states also provide recommendations on

how domestic septage should be land applied (U.S.

EPA, 1994b). In addition, states usually issue hauler

licenses, although some states delegate this authority to

counties or other municipal agencies (U.S. EPA, 1994b).

Since promulgation of the Part 503 federal regulation,

many states have reviewed their regulations regarding land application of sewage sludge and domestic

septage. Those states that have regulations less stringent than the federal regulation will likely change state

regulations to meet the minimum federal requirements (U.S. EPA, 1994b). For further assistance with

applicable state regulations, contact your state septage

coordinator.

11.3 Adjusting the pH of Domestic

Septage

The Part 503 regulation regarding land application of

domestic septage is less burdensome if alkali stabilization is practiced. Stabilization is a treatment method

designed to reduce levels of pathogenic organisms,

lower the potential for putrefaction, and reduce odors.

Stabilization methods for domestic septage are summarized in Table 11-4 (U.S. EPA, 1994a). The simplest and

most economical technique for stabilization of domestic

septage is pH adjustment. Usually, lime is added to

liquid domestic septage in quantities sufficient to increase the pH of the septage to at least 12.0 for 30

minutes (U.S. EPA, 1994b). If the lime is added before

or during pumping of the septic tank, in many cases 30

minutes will elapse before the truck reaches the land

application site. Other stabilization options, such as

aerobic digestion, are relatively simple but have higher

capital and operating costs (U.S. EPA, 1994b), and

cannot be used to meet Part 503 domestic septage

treatment requirements (for application to agricultural

land, forests, or reclamation sites).

To raise the pH of domestic septage to 12 for 30 minutes, sufficient alkali (e.g., at a rate of 20 lb to 25 lb of

lime [as CaO or quicklime] per 1,000 gal [2.4 kg to 3.6

kg per 1,000 L]) of domestic septage typically is needed,

although septage characteristics and lime requirements

vary widely (U.S. EPA, 1994b). EPA recommends the

following approaches for alkali stabilization prior to land

application (U.S. EPA, 1994b):

• Addition of alkali slurry to the hauler’s truck before

the domestic septage is pumped into the truck, with

additional alkali added as necessary after pumping.

• Addition of alkali slurry to the domestic septage as it

is pumped from the septic tank into the hauler’s truck.

(Addition of dry alkali to a truck during pumping with

a vacuum pump system is not recommended; dry

alkali will be pulled through the liquid and into the

vacuum pump, causing damage to the pump.)

• Addition of either alkali slurry or dry alkali to a holding

tank containing domestic septage that has been discharged from a pumper truck.

Many states allow domestic septage to be alkali-stabilized within the truck. Some states, however, prohibit

alkali stabilization in the hauler’s truck and require a

separate holding/mixing tank where alkali addition and

pH can be easily monitored. A separate holding and

mixing tank is preferred for alkali stabilization for the

following reasons (U.S. EPA, 1994b):

• More rapid and uniform mixing can be achieved.

• A separate holding and mixing tank affords more control over conditions for handling and metering the

proper quantity of alkali.

• Monitoring of pH is easier, and more representative

samples are likely to be collected due to better mixing.

• Raw domestic septage can be visually inspected.

To prevent damage to vacuum pumps and promote

better mixing of the alkali and domestic septage, alkali

should be added as a slurry (U.S. EPA, 1994b). The

slurry can be added to the truck before pumping the

tank, although the amount of alkali necessary to reach

pH 12 will vary from load to load. Provisions should be

made to carry additional alkali slurry on board the truck

to achieve the necessary dosage (U.S. EPA, 1994b).

Compressed air injection through a coarse-bubble diffuser system is the recommended system for mixing the

contents of a domestic septage holding tank. Mechanical

134
mixers are not recommended because they often become fouled with rags and other debris present in the

septage (U.S. EPA, 1994b).

Figure 11-6 presents a procedure for alkali-stabilizing

septage within the pumper truck. Methods recommended by domestic septage servicing professionals

are presented in Domestic Septage Regulatory Guidance (U.S. EPA, 1993), along with associated cautions.

If pH adjustment is used for domestic septage, the Part

503 requirements apply to each truckload unless pH

adjustment was done in a separate treatment device

(e.g., lagoon or tank) (U.S. EPA, 1993).

11.3.1 Sampling for pH

Land appliers of domestic septage should not automatically assume that the lime or other alkali material added

to domestic septage and the method of mixing chosen

will adequately increase pH. The pH must be tested. A

representative sample should be taken from the body of

the truckload or tank of domestic septage for testing. For

example, a sampling container could be attached to a rod

or board and dipped into the domestic septage through

the hatch on top of the truck or tank or through a sampling

port (U.S. EPA, 1993). Alternatively, a sample could be

taken from the rear discharge valve at the bottom of the

truck’s tank. If the lime has settled to the bottom of the tank,

however, and has not been properly mixed with the domestic septage, the sample will not be representative.

Two separate samples should be taken 30 minutes

apart, and both of the samples must test at pH 12 or

greater (with the pH reading converted to an equivalent

value at 25°C to account for the influence of hot and cold

weather on meter readings). If the pH is not at 12 or

greater for a full 30 minutes, additional alkali can be

added and mixed with the domestic septage. After mixing in the additional alkali, however, the domestic septage must be at 12 or greater for a full 30 minutes to

meet the pH requirement of the Part 503 regulation

(U.S. EPA, 1993).

Table 11-4. Summary of Domestic Septage Stabilization Options (U.S. EPA, 1994b)

Method Description Advantages Disadvantages

Alkali sltabilizationa Lime or other alkaline material

is added to liquid domestic

septage to raise pH to 12.0 for

minimum of 30 min.

Very simple; minimal operator 

attention.

Low capital and O&M costs.

Provides temporary reduction in

sulfide odors.

Meets EPA criteria for reduction

in vector attraction.

Reduces EPA site restriction

requirements for land application.

Increases mass of solids

requiring disposal.

Handling of lime may cause

dust problems.

Lime feed and mixing

equipment require regular

maintenance.

Aerobic digestion Domestic septage is aerated for

15 d to 20 d in an open tank to

achieve biological reduction in

organic solids and odor

potential. (Time requirements

increase with lower

temperatures.)

Relatively simple.

Can provide reduction in odors.

High power cost to operate

aeration system.

Large tanks or basins required.

Cold temperatures require much

longer digestion periods.

Anaerobic digestion Domestic septage is retained for

15 d to 30 d in an enclosed

vessel to achieve biological

reduction in organic solids.

Generates methane gas, which

can be used for digester heating

or other purposes.

Requires skilled operator to

maintain process control.

High maintenance requirements

for gas handling equipment.

High capital costs.

Generally not used except for

co-treatment with sewage

sludge.

Composting Liquid domestic septage or

domestic septage solids are

mixed with bulking agent (e.g.,

wood chips, sawdust) and

aerated mechanically or by

turning. Biological activity

generates temperatures

sufficiently high to destroy

pathogens.

Final product is potentially

marketable and attractive to

users as soil amendment.

Costly materials handling

requirement.

Requires skilled operator

process control.

High odor potential.

High operating costs.

a

 Only alkali stabilization meets Part 503 domestic septage treatment requirements.

135
11.4 Methods of Application

The most common, and usually most economical,

method for using or disposing domestic septage is land

application (e.g., land spreading, irrigation, incorporation). Various options for land applying domestic septage are summarized in Table 11-5 (U.S. EPA, 1994b).

The simplest application method involves a hauler truck

applying domestic septage by opening a valve and driving across the land application site. A splash plate or

spreader plate improves domestic septage distribution

onto the soil surface. The domestic septage should be

discharged through a simple screen or basket located

on the truck between the outlet pipe and the spreader

plate. This screen prevents nondegradable materials

such as plastics and other objectionable trash from

being applied to the soil. A simple box screen can be

fabricated from expanded metal. Collected trash should

be lime-stabilized and sent to a sanitary landfill. The

domestic septage must be lime-stabilized prior to surface application, injected below the surface, or plowed

into the soil within 6 hours of application to meet federal

Part 503 requirements for vector attraction reduction

(U.S. EPA, 1994b).

While relatively easy, the application method described

above also is the least flexible and is difficult to control

from a management perspective. In addition, soil may

become compacted, and trucks not designed for offroad use may have difficulty driving on the site. Small,

rural land application operations where little environmental or human health risk is likely to occur, however,

may find this approach acceptable. A transfer or storage

tank must be available when sites are inaccessible due

to soil, site, or crop conditions (U.S. EPA, 1994b).

Another common approach is to use a manure spreader

or a special liquid-waste application vehicle that removes screened domestic septage from a holding tank

and spreads it on or injects it below the soil surface. If

the domestic septage is incorporated into the soil by

plowing or is injected, pH adjustment may not be

required to meet the Part 503 vector attraction reduction requirements (U.S. EPA, 1994b). If pH adjustment

is done, this also meets some of the Part 503 requirements for pathogen reduction. Figure 11-7 illustrates

a subsurface injection device that injects either a wide

band or several narrow bands of domestic septage

into a cavity 10-15 cm (4 to 6 in) below the soil surface

(U.S. EPA, 1980).

A third approach is to pretreat the domestic septage

(with a minimum of screening) during discharge into a

holding/mixing tank by adding lime and stabilizing it to

pH 12 for 30 min, and then to spray the domestic septage onto the land surface using commercially available

application equipment. Adjustment of pH reduces odors

and eliminates the need to incorporate the domestic

septage into the soil (U.S. EPA, 1994b).

Purpose To raise the pH of domestic septage to 12 for a

minimum of 30 min.

Approach • Add lime slurry in sufficient quantity before

pumping the tanks and add additional slurry as

needed after pumping.

• Add lime slurry in sufficient quantity during

pumping of the tanks by vacuuming slurry

through small suction line fitted to main suction

hose.

Type of lime • Pulverized quicklime (CaO).

• Hydrated lime (Ca(OH)2).

(Less quicklime is required than is hydrated lime

to achieve the same pH, but quicklime is more

corrosive and difficult to handle.)

Dosage Typically 20 lb to 25 lb quicklime per 1,000 gal of

domestic septage (or about 26 lb to 33 lb of

hydrated lime per 1,000 gal).

Slurry Approximately 80 lb of pulverized quicklime or

hydrated lime in 50 gal of water. Mix mannually

with paddle in a 55-gal drum or in a 200-gal

polyethylene tank with electric mixer (preferred).

CAUTION: Heat is liberated when quicklime is

added to water. Wear rubber gloves, appropriate

respirator (for dust), and goggles. Add lime slowly

to partially full tank. an emergency eyewash

station should be located nearby.

Application

rate

Typically 12 to 15 gal quicklime slurry per 1,000

gal of domestic septage (or 15 gal to 20 gal

hydrated lime slurry).

Monitoring After lime slurry has been mixed with domestic

septage, collect sample from top access hatch using

a polyethylene container fastened to a pole. Measure

pH with pH meter at 25°C (or convert reading to

25°C). (pH paper can also be used, but it is more

cumbersome and less accurate.) If the pH is less

than 12, add more slurry. If pH 12 has been reached,

record pH and time. Sample again after 15 min. If the

pH has dropped below 12, add more lime. The pH

must remain at 12 for at least 30 min. Sample and

record pH prior to applying septage to the land.

Figure 11-6. Procedure for lime-stabilizing domestic septage

within the pumper truck (U.S. EPA, 1994b).

Figure 11-7. Subsurface soil injection (Cooper and Rezek,

1980).

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11.5 Operation and Maintenance at Land

Application Sites Using Domestic

Septage

Key elements of a successful operation and maintenance program for a domestic septage land application

site include (U.S. EPA, 1994b):

• Provision of receiving and holding facilities for the domestic septage to provide operational flexibility (optional).

• Proper domestic septage treatment prior to application as required to meet federal and state regulations

(need for treatment depends on requirements of application method).

• Control of domestic septage application rates and

conditions in accordance with federal and state rules.

• Proper operation and maintenance of the application

equipment.

• Monitoring of domestic septage volumes and characteristics, as well as soil, plant, surface water and ground

water as required by federal and state regulations.

• Odor control.

• Good recordkeeping and retention of records for at

least 5 years.

Table 11-5. Summary of Land Application Methods for Domestic Septage (U.S. EPA, 1994b)

Method Description Advantages Disadvantages

Surface Application (for all surface application methods, domestic septage must be incorporated into soil within 6 hrs if the pH is

not adjusted and if the septage is applied to agricultural land, forest, or a reclamation site.)

Spray irrigation Pretreated (e.g., screened)

domestic septage is pumped

through nozzles and sprayed

directly onto land.

Can be used on steep or rough

land.

Minimizes disturbance of soil by

trucks.

Large land area required.

High odor potential during application.

Storage tank or lagoon required during

periods of wet or frozen ground.

Potential for nozzle plugging.

Ridge and furrow

irrigation

Pretreated domestic septage is

applied directly to furrows.

Lower power requirements and

odor potential than spray

irrigation.

Limited to 0.5% to 1.50% slopes.

Storage lagoon required.

Hauler truck

spreading

Domestic septage is applied to

soil directly from hauler truck

using a splash plate to improve

distribution.

Same truck can be used for

transport and disposal.

High odor potential during and

immediately after spreading.

Storage tank or lagoon required during wet

or freezing conditions.

Slope may limit vehicle operation.

Hauler truck access limited by soil

moisture; truck weight causes soil

compaction.

Farm tractor and

wagon spreading

Domestic septage is transferred

to farm equipment for spreading. 

Increases opportunities for

application compared to hauler

truck spreading.

High odor potential during and

immediately after spreading.

Storage tank or lagoon required.

Requires additional equipment (tractor and

wagon).

Subsurface Incorporation

Tank truck or

farm tractor with

plow and furrow

cover

Liquid domestic septage is

discharged from tank into furrow

ahead of single plow and is

covered by second plow.

Minimal odor and vector

attraction potential compared

with surface application.

Satisfies EPA criteria for

reduction of vector attraction.

Slope may limit vehicle operation.

Storage tank or lagoon required during

periods of wet or frozen ground.

Subsurface

injection

Liquid domestic septage is

placed in narrow opening

created by tillage tool.

Minimal odor and vector

attraction potential compared

with surface application.

Satisfies EPA criteria for

reduction of vector attraction.

Slope may limit vehicle operation.

Specialized equipment and vehicle may be

costly to purchase, operate, and maintain.

Storage tank or lagoon required during wet

or frozen conditions.

137
Odor problems should not arise at a site where domestic

septage is land applied if the requirements of Part 503

are followed. A well-managed operation that uses pH

adjustment and practices subsurface injection or surface application/incorporation at or below agronomic

rates (see Section 11.2.1.1) will create minimal odor

emissions. Additional guidelines for minimizing odor

problems at land application sites are presented in

EPA’s Guide to Septage Treatment and Disposal (U.S.

EPA, 1994b).

Operation and maintenance requirements for land application of domestic septage vary widely depending on

the application technique and the type of equipment used.

11.6 References

When an NTIS number is cited in a reference, that

document is available from:

 National Technical Information Service

 5285 Port Royal Road

 Springfield, VA 22161

 703-487-4650

U.S. EPA. 1994a. A plain English guide to the Part 503 biosolids rule.

EPA/832/R-93/003. Washington, DC.

U.S. EPA. 1994b. Guide to septage treatment and disposal. EPA/625/

R-94/002. Cincinnati, OH.

U.S. EPA. 1993. Domestic septage regulatory guidance: A guide to

the Part 503 rule. EPA/832/B-92/005. Washington, DC.

U.S. EPA. 1992a. Technical support document for land application of

sewage sludge. EPA/822/R-93/001a (NTIS PB93110583). Washington, DC.

U.S. EPA. 1992b. Environmental regulations and technology: Control

of pathogens and vector attraction in sewage sludge. EPA/625/R92/013. Washington, DC.

U.S. EPA. 1980. Septage management. EPA/600/8-80/032. (NTIS PB

81142481). Washington, DC.

138
Chapter 12

Public Participation

12.1 Introduction

A critical factor in establishing a sewage sludge land

application program in most communities is the participation of local citizens from the beginning and at various

key stages of the project’s development. If not given the

opportunity to discuss their concerns, whether based on

legitimate issues or misperceptions, resistance from

members of the community can significantly complicate

a project and result in additional costs. Moreover, if the

public’s viewpoint is ignored until late in the planning

process, opposition within the community may solidify

and be difficult to overcome. Thus, public participation

is as important a factor as any technical consideration

in establishing a sewage sludge land application system

(Lue-Hing et al., 1992). Public involvement in the decision-making process will help to minimize opposition

and to identify the major barriers to local acceptance

(U.S. EPA, 1984).

A sewage sludge land application project has the best

chance of gaining public acceptance if a public outreach effort is organized to stress the demonstrated

value of sewage sludge as a resource. Once acceptance has been achieved, it is most likely to be maintained through conscientious management of the site

during operations.

In general, the public’s willingness to participate in—and

ultimately accept—the siting of a sewage sludge land

application site will depend on:

• An understanding of the need for the project regarding its costs and benefits.

• A sense of confidence that the project will adequately

protect public health and safeguard the environment.

• Encouragement of active public involvement in project development so that local interests can be factored into the plan.

Planning for public participation in the siting of a sewage

sludge land application site involves careful and early

evaluation of what should be communicated, to whom,

by whom, and when. This chapter summarizes the major

considerations for implementing a successful public participation program, including the objectives and value of

a public participation, the design and timing of a program, and topics generally of public concern regarding

the land application of sewage sludge.

12.2 Objectives

The objectives of a public participation program are:

• Promoting a full and accurate public understanding

of the advantages and disadvantages of land application of sewage sludge.

• Keeping the public well-informed about the status of

the various planning, design, and operation aspects

of the project.

• Soliciting opinions, perceptions, and suggestions

from concerned citizens involving the land application

of sewage sludge.

The key to achieving these objectives is to establish

continuous two-way communication between the public

and the land application site planners, engineers, and

eventual operators (Canter, 1977). Officials need to

avoid the common assumption that educational and

other one-way communication techniques will promote

adequate dialogue. A public participation plan should

focus generally on moving people from the typical reactive response to sewage sludge issues to an informed

response about sludge management (Lue-Hing et al.,

1992).

To generate meaningful public participation in the decision-making process, the public agency or engineering

firm directing the project needs to take particular steps

at each stage of project development (see Section 12.3).

The additional effort involved in soliciting community

input for establishing a land application site should be

considered when making an initial determination about

the best approach for managing the community’s sewage sludge.

12.3 Implementation of a Public

Participation Program

A program for soliciting public participation in the siting

of a sewage sludge land application site should be

tailored to fit the scale and costs of the particular project.

139
Nonetheless, a basic framework for a program that

would be applicable for most situations includes:

• The initial planning stage

• The site selection stage

• The site design stage

• The site preparation and operation stage

These four stages are described below. Beyond this

basic framework, officials should use a common-sense

approach for determining the extent of the public participation program and the frequency at which public input

should be solicited. When time and money are constraining factors, officials will need to concentrate resources on the most effective mechanisms for community

involvement (see Table 12-1). Regardless of its scope,

however, the public participation program will need to be

flexible enough to accommodate various issues that can

arise in the course of establishing a sewage sludge land

application site.

12.3.1 Initial Planning Stage

12.3.1.1 Establishing an Advisory Committee

During the initial planning stage, the scope and scale of

the public participation program is decided, and implementation of the program is then initiated. To facilitate

and follow through with this effort, officials in charge of

the land application project should organize an advisory

committee made up of members of the community. The

committee should include, for example, representatives

of local government, community organizations, and area

businesses (Table 12-2). Since in rural communities the

acceptance of local farmers is particularly important for

a proposed land application program, this group should

also be represented on the committee where appropriate (see Section 12.4.1). The Soil Conservation Service,

county Extension Agents, and Farm Bureau can provide

vital links with the farming community (U.S. EPA, 1984).

The primary responsibility of the advisory committee

should be to organize the community’s involvement in

project planning. The overall strategy for informing the

community about the land application project and responding to concerns should be put in writing. Additionally, the committee could be called upon to provide initial

Table 12-1. Relative Effectiveness of Public Participation

Techniques

Communication Characteristics

Public Participation

Technique

Level of

Public

Contact

Achieved

Ability to

Handle

Specific

Interest

Degree of 

Two-Way

Communication

Public hearings M L L

Public meetings M L M

Advisory Committee

meetings

LH H

Mailings M M L

Contact persons L H H

Newspaper articles H L L

News releases H L L

Audiovisual

presentations

ML L

Newspaper

advertisements

HL L

Posters, brochures,

displays

HL L

Workshops L H H

Radio talk shows H M H

Tours/field trips L H H

Ombudsman L H H

Task force L H H

Telephone line H M M

L = low value

M = medium value

H = high value

Table 12-2. Potential Advisory Committee Members (Canter,

1977)

The following groups and individuals should be contacted

about serving on the advisory committee:

• Local elected officials.

• State and local government agencies, including planning

commissions, councils of government, and individual agencies.

• State and local public works personnel.

• Conservation/environmental groups.

• Business and industrial groups, including chambers of commerce

and selected trade and industrial associations.

• Property owners and users of proposed sites and neighboring

areas.

• Service clubs and civic organizations, such as the League of

Women Voters.

• The media, including newspapers, radio, and television.

The following groups should also be contacted, where

appropriate:

• State elected officials.

• Federal agencies.

• Farm organizations.

• Educational institutions, including universities, high schools, and

vocational schools.

• Professional groups and organizations.

• Other groups and organizations, such as urban groups, economic

opportunity groups, political clubs and associations.

• Labor unions.

• Key individuals who do not express their preferences through, or

participate in, any groups or organizations.

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feedback on various project proposals and to function

generally as a liaison between the project staff and the

community at large. In its role as liaison, an advisory

committee would be responsible for receiving community input and obtaining responses to questions. A useful

practice in this regard is to keep a log of requests for

information and responses given. For especially large

projects, it might be feasible to hire a public information

professional to assist in this capacity.

When making its assessment about the appropriate extent of the public outreach effort, the advisory committee’s planning should address when and how often to

use particular mechanisms for encouraging participation

in the land application project. The two general types of

program mechanisms are:

• Educational. Those that allow project staff to present

information to members of the community.

• Interactive. Those that are intended to solicit input

from members of the community.

Throughout the public participation program, the advisory committee should be developing its mailing and

telephone lists. Such lists, which should be continually

updated and expanded by capturing the names of citizens who attend public meetings or otherwise make

contact with the committee, can prove indispensable for

keeping the community involved in the land application

project. Contact by mail and telephone can be used to

alert the community to meetings and developments, or

to provide followup information to citizens who have

expressed particular concerns about the project.

12.3.1.2 Educating the Community

After establishing an advisory committee, the next step

in program implementation is to undertake a public education campaign, which typically is kicked off at a wellpublicized public meeting or at a series of meetings

targeted for specific groups within the community.

The level of interest in waste management issues for

most people is fairly low. Thus, while members of the

community at large should be targeted by the public

education campaign, it is particularly important to reach

members of environmental groups, the media, and

elected officials. The participation of such members of

the community is important because they are likely to

have broad affiliations and the ability to affect public

opinion on a large scale (WEF, 1992).

At a public meeting it is important to present general

information about the land application project and to

encourage the community to take an active interest in

the project’s development. Presenters at this meeting

might include project staff and engineering consultants.

The meeting is also a good opportunity to introduce the

members of the advisory committee—stressing the

breadth of representation from the various sectors of the

community—and explain the committee’s role. Information about the project presented at the community meeting should cover:

• The need for the land application program.

• The reason for selecting land application over other

approaches for managing sewage sludge, such as

surface disposal or incineration.

• The use of crops or other vegetation grown on the site.

• The general costs associated with design, construction, and operation of the program.

• The potential economic incentives, such as job creation and stimulation of the local economy.

• The program’s general design and operation principles.

It may be useful to supplement presentations given at

the meeting with handouts that provide, for instance, a

brief explanation of sewage sludge and how it is generated; a nontechnical summary of the Part 503 rule; the

professional experience of engineers and others designing the land application program; and a list project contacts. Video support, if available, might also be useful

for providing additional general information at the

meeting.

A community’s specific concerns, particularly about protecting public health and safeguarding the environment,

can be enough to undermine a technically strong plan

for establishing a land application operation. Thus, it is

advisable to make information available about how land

application programs operating over long periods (e.g.,

10 years or more) in other communities have addressed

these concerns (Jacobs et al., 1993).

Once the sewage sludge land application project has

been introduced at a public meeting to interested members of the community, informational outreach to the

general public can be achieved primarily through the

local media. Since public meetings are ineffective information outlets for certain segments of any community,

however, the outreach effort should include placing paid

advertisements, if feasible, as well as encouraging the

media contacts made at the public meeting to report on

the project. At some point after providing the media with

general information about the proposed land application

site, it may be useful to develop a press kit for distribution. Providing project-specific information to the media

will increase the accuracy of information reported to the

public (Lue-Hing et al., 1992).

The more types of media that are used to promote the

project, the greater the likelihood of a successful outreach effort. For example, a variety of media could be

used as follows:

141
• Newspapers reports. A series of articles on land application of sewage sludge could be timed to appear

throughout the project to sustain public interest. Also,

occasional news releases would keep the community

informed about developments.

• Television reports. At a minimum, it should be possible to arrange for coverage of milestone project developments. It also might be possible to interest news

producers in developing a series about the project.

• Newspaper, television, and radio advertisements. Informational advertisements can be used to publicize

critical information about the project. Although television advertising tends to be expensive, it can be

particularly effective for reaching a majority of the

community. Radio advertising, especially if broadcast

during the morning or afternoon commute, can be

equally effective while less expensive.

• Public service announcements and editorials. Radio

and television stations are required to offer a limited

amount of broadcast time for airing announcements

or editorials of general interest in the local area. Cable television stations may have specific programming devoted to local issues. Also, newspapers may

welcome an informed opinion piece for the op-ed page.

Posters, brochures, and displays also can be highly

effective educational tools, especially when designed

creatively and placed in high-traffic areas or given wide

distribution.

12.3.1.3 Soliciting Community Input and

Addressing Concerns

After the public has been generally informed about the

sewage sludge land application project, the advisory

committee should begin concentrating its efforts on soliciting community input on the project plan. For this

phase of the public participation program, various types

of forums can be useful for focusing on and responding

to the community’s concerns about the project. Concerns that are likely to surface include:

• Public safety and health. As noted above, this issue

can be of primary interest to the community. Thus, it

is important to emphasize the extensive research on

risk assessment and environmental impacts that

serves as the basis for the Part 503 rule. Also, project-specific management systems should be explained. In particular, the community may need to be

reassured that a system has been developed for

avoiding spills of sewage sludge during transport.

• Contamination of water supplies. The public generally

has developed a heightened awareness about water

quality issues. As a result, the public is better prepared to raise water quality issues and to consider

measures taken to safeguard water supplies. The

community should be made aware that Part 503 specifically addresses protection of ground water and

surface waters by, for instance, restricting runoff from

application sites and limiting the potential for leaching

of pollutants into ground water.

• Accumulation of heavy metals and toxics. The public

may be inclined to assume that sewage sludge is

associated with excessive contaminants, since

“waste” is synonymous with “toxic” in many people’s

minds (Lue-Hing et al., 1992). Thus, public information efforts should stress the proven beneficial characteristics of sewage sludge and explain the

regulatory limits on the loadings of 10 heavy metals

associated with sewage sludge.

• Regulatory compliance. The community is likely to

question whether the site will be monitored by public

officials for regulatory compliance. This concern can

be addressed by explaining the role of the permitting

authority in enforcing the Part 503 rule and by reviewing the legal recourse available to officials (e.g., fines

of up to $25,000 per day for a single violation).

• Odor, noise, dust, and traffic. Because odors are usually the first cause of complaints when a land application site is sited near a residential area, sewage

sludge at such sites should be injected or disked into

the soil immediately following application (Jacobs et

al., 1993). The site management plan should specifically cover such measures, as well as measures to

control noise and dust from the operation of machinery and limit traffic in and out of the site.

• Land values. The community is likely to be concerned

about the impact of the land application operation on

real estate values. This issue should be investigated

and the community should be informed of any potential for a drop in values. Regarding this and other

concerns, it may be useful to cite the experience of

other communities with a land application program

(Jacobs et al., 1993).

Both formal and informal approaches can be effective

for soliciting and then responding to the community’s

concern about the land application project. Regardless

of the forum, however, it is essential that advantages as

well as disadvantages be addressed openly. When there

is a void of information, it is likely to get filled with

distorted portrayals based on assumptions and emotion.

It is far better to fill that void with factual information

(Lue-Hing et al., 1992).

Forums that can be effective for public participation

include meetings and workshops, as well as site tours

that include demonstrations. The appropriateness of a

particular forum will depend on the stage of the project’s

development.

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12.3.2 Site Selection Stage

The site selection process involves screening an array

of potential locations for the land application facility,

followed by detailed field investigations that include

water and soil sampling at a handful of candidate sites.

Once the project staff has narrowed the choices down

to a few sites and gathered a reasonable amount of

comparative data, the public should be brought into the

process.

Depending on the scope of the project and the location

of candidate sites relative to population density, the

appropriate forum for public participation at this stage

would be a targeted meeting or a workshop gathering.

If a site close to a residential area is being seriously

considered, neighboring residents will have a vested

interest in selection and want detailed information about

such issues as public safety, odor control, and impact

on land values. Indeed, project staff may need to anticipate vocal, organized resistance to the site. Meeting

with interested parties in smaller groups can be an

effective means of diffusing such emotionally loaded

issues. Targeted meetings and workshops have particular characteristics that are advantageous at this stage of

project development:

• Targeted meetings. Meeting with members of the

community who have a particular interest in the project can be an efficient means of addressing site-specific concerns. A useful approach is to give the

community an opportunity to discuss issues directly

with project engineers, the prospective site manager,

and members of the advisory committee. These

smaller meetings should be less structured than the

initial, community-wide meeting so that dialogue can

be encouraged. A sketchy outline should be used

primarily to elicit a group’s concerns, and the project

staff should be fully prepared to respond to a range

of issues.

• Workshops. When working with a group that is particularly interested in site-selection criteria, such as

an environmental group or the media, a workshop is

a useful forum for presenting and discussing information. A fairly structured agenda is appropriate for a

workshop, as long as sufficient time is scheduled for

open discussion. If a workshop is effective, participants are likely to disseminate the information more

broadly within the community.

To generate participation in these more focused gatherings, the advisory committee might want to use its telephone and mailing lists to contact potentially interested

individuals. Otherwise, opposition to the site finally selected could surface late in the process, when it may be

less readily diffused. For the same reason, it is important

to keep the community involved through completion of

the selection process.

When opposition to the developing plan does arise, it is

best to meet it head on. Recommended presentation

tactics (Lue-Hing et al., 1992) include:

• Answer all questions candidly and publicly.

• Avoid arguing over emotionally charged questions;

emphasize generalities.

• Never reiterate incorrect information, either verbally

or in print.

12.3.3 Site Design Stage

Because the relevant information at this stage of the

project is of a particularly technical nature, community

interest will be less broad-based. Nonetheless, it is important to maintain some degree of public participation.

This challenge is likely to fall to the advisory committee,

which should consider various and innovative approaches for reaching the public with design information. Suggested approaches include:

• Field trips. A visit to a nearby operating land application site can be a useful means of informing special

interest groups about design considerations. A project

engineer should accompany the group on the visit so

that the host site can be compared to the planned

site.

• Video presentations. If available, a general video that

explains site design in regard to eventual operation

can be an effective means of involving the community

in the project’s design stage. The video could be

screened for small groups and followed by a question

and answer period with project staff.

• Task forces. Assigning members of the community to

design-related tasks that address specific public concerns can generate important input for design planning. To be most effective, task force members

should have a technical orientation.

• Media campaign. Information (e.g., press releases)

should be provided to the media as design milestones are reached. A guest appearance on a radio

call-in program or a cable news program by a project

spokesperson might also be effective at this stage if

it can be arranged.

Once the design for the land application site is final, it

will need to be formally presented to the community at

a public hearing. Such gatherings are often legally required, must be preceded by published notification to the

community, and follow a set agenda. Also, relevant materials might need to be made available for public review

prior to the hearing. The agenda for a public hearing

usually includes presentations by project staff, after

which the floor is opened for comments from the community. The effectiveness of the gathering can be enhanced when an elected official or other prominent,

143
informed figure in the community chairs the hearing or

at least participates.

12.3.4 Site Preparation and Operation Stage

While the selected land application site is being prepared for operations, the advisory committee should

monitor activity at the site and maintain contact with the

community. This is particularly important if buildings or

treatment structures are being constructed, since the

delivery of materials and operation of heavy equipment

can create nuisances, especially for local residents.

Committee members should be prepared to respond to

complaints as they arise, either on their own or with the

help of the project staff. If feasible, the project staff

should assign an ombudsman to resolve issues that

arise during site preparation and to continue in this

capacity, at least initially, once operations are under way.

Once fully operational, the site should continue to be

monitored for its actual or potential negative impacts on

the community. After an initial period of operation, the

advisory committee may want to conduct a limited telephone survey to gauge how the public is feeling about

the site. The committee would then report results to the

operations staff and follow up to see that any necessary

modifications have been made. For example, better

odor control practices may need to be adopted, or site

traffic may need to be restricted to specified hours.

After the advisory committee has determined that the

land application site has been generally accepted by the

community, it should provide followup information to the

media. This is the appropriate point to promote the

success of the site and its advantages to the community—not the least of which should be the beneficial use

of locally generated sewage sludge. For instance, the

community should be interested in learning about the

use of crops grown on the site and whether local gardeners are land applying sewage sludge.

12.4 Special Considerations

12.4.1 Agricultural Sites

Implementation of an agricultural land application project for sewage sludge can require acceptance and

approval by local officials, farmers, landowners, and

other affected parties. Public resistance to agricultural

land application of sewage sludge can stem from fear

that the sludge may contain concentrations of organic or

inorganic substances that could be toxic to plants or

accumulate in animals or humans consuming crops

grown on sludge-treated lands.

The most critical aspect of a public participation program

in such cases is securing the involvement of farmers

who will use the sludge. How this involvement is to

be secured during the planning process depends on

the individual communities involved; their past experiences with land application systems; overall public

acceptance of the concept; and the extent to which

related or tangential environmental concerns are voiced

in the community.

Generally, a low-key approach is most effective. The

various approaches can consist of one or more of the

following steps:

• Check with the wastewater treatment operator to see

if any local farmers have requested sewage sludge

in the past.

• Have the local Soil Conservation Service or Agricultural Extension Service agent poll various individuals

in the area.

• Describe the project in the local newspaper, asking

interested parties to contact the extension agent.

• Personally visit the identified parties and solicit their

participation. A telephone contact will elicit little support unless followed by a personal visit.

The use of demonstration plots is very effective in promoting the land application of sewage sludge by farmers. If farmers can compare crops grown on sludge-treated

soil with these grown with conventional fertilizer, their willingness to use sewage sludge will increase markedly

(Miller et al., 1981). The following questions regarding

sewage sludge land application need to be discussed

with landowners:

• How long is the landowner willing to participate (e.g.,

a trial period of 1 or more years; open-ended participation; until one or both parties decide to quit; for a

prescribed period of time)?

• What crops are traditionally planted, and what is the

usual crop rotation?

• If the sewage sludge characteristics were such that

a different crop is desirable, would the landowner be

willing to plant that crop?

• Which fields would be included in the sewage sludge

land application program?

• Under what conditions would the landowner accept

the sewage sludge, what time of the year, and in what

quantities?

• Is the landowner willing to pay a nominal fee for the

sewage sludge, accept it free of charge, or must the

municipality pay the landowner for accepting sludge?

• Is the landowner willing to engage in special procedures (e.g., maintaining soil pH at 6.5 or greater)?

The public participation program should emphasize both

the benefits and the potential problems of applying sewage sludge on cropland.

144
12.4.2 Forest Sites

To help achieve acceptance, a program for the land

application of sewage sludge at a forest site should

satisfactorily address the following questions:

• How will public access be controlled in the application

area for an appropriate period (normally 12 to 18

months) after sewage sludge application? Forested

areas are often used for various recreational activities

(e.g., picnicking, hiking, gathering of forest products).

Even privately owned forest land often is viewed by

the public as accessible for these purposes. The

owner of the land, private or public, will have to agree

to a method for controlling public access (e.g., fence,

chain with signs). The public, through its representatives,

must agree to restrictions if the land is publicly owned.

• Will public water supplies and recreational water resources be adequately protected against contamination? This concern should be covered by proper

siting, system design, and monitoring. Public health

authorities and regulatory agencies must be satisfied

and involved in the public participation program.

Careful consideration must be given to municipal watersheds and/or drinking water recharge areas to

avoid contamination.

• Will the applied sewage sludge cause adverse effects

to the existing or future trees in the application area?

Based on the available data from research and demonstration projects, many tree species, with few

exceptions, respond positively to sewage sludge

application, provided the sludge is not abnormally high

in detrimental constituents and proper management

practices are followed.

• Unlike most agricultural applications, there is much

less concern about possible food chain transmission

of contaminants to humans. The consumption of wild

animals by hunters and their families will occur, but

there is little potential for contamination of meat from

such animals through contact with a properly managed sludge application area.

12.4.3 Reclamation Sites

Prior to the initiation of any reclamation project using

sewage sludge, it will likely be necessary to educate the

public to gain public acceptability. The task may be

difficult with lands disturbed by mining, because local

opposition to mining activity already exists in many

cases. This is particularly true if the mining activity has

already created some adverse environmental problems,

such as reduced local ground-water quality, acid mine

drainage, or serious soil erosion and sedimentation of

local streams.

Citizens, regulatory agencies, and affected private business entities need to participate in the planning process

from the beginning. The most effective results are usually achieved when industry, citizens, planners, elected

officials, and state and federal agencies share their

experience, knowledge, and goals, and jointly create a

plan acceptable to all.

12.5 References

Canter, L. 1977. Environmental impact assessment. New York, NY:

McGraw-Hill. pp. 221, 222.

Jacobs, L., S. Carr, S. Böhm, and J. Stukenberg. 1993. Document

long-term experience of biosolids land application programs. Project 91-ISP-4, Water Environment Research Foundation, Alexandria, VA.

Lue-Hing, C., D. Zenz, R. Kuchenrither, eds. 1992. Municipal sewage

sludge management: Processing, utilization and disposal, Ch. 12.

In: Water quality management library, Vol. 4. Lancaster, PA: Technomic Publishing.

Miller, R., T. Logan, D. Forester, and D. White. 1981. Factors contributing to the success of land application programs for municipal

sewage sludge: The Ohio experience. Presented at the Water

Pollution Control Federation Annual Conference, Detroit, MI.

U.S. EPA. 1984. Environmental regulations and technology: Use and

disposal of municipal wastewater sludge. EPA/625/10-84/003.

Washington, DC.

WEF. 1992. Proceedings of the future direction of municipal sludge

(biosolids) management: Where we are and where we’re going,

Vol. 1, Portland, OR, July 26-30, 1992. Water Environment Federation, Alexandria, VA. No. TT041.

145
Chapter 13

Monitoring and Sampling

13.1 Overview

The Part 503 rule requires monitoring of sewage sludge

that is land applied for metal concentrations, pathogen

densities, and vector attraction reduction. In addition,

soil testing for nutrients (N, P, and K) may be useful at

land application sites to help determine plant nutrient

needs. Additional monitoring (e.g., of water quality and

vegetation) is not required by Part 503 for land application sites because the rule protects these resources

through pollutant limits, management practices, pathogen reduction requirements, etc.

This chapter discusses Part 503 monitoring requirements for sewage sludge, including required analytical

methods, and specifies sampling procedures that might

be particularly useful for characterizing sewage sludge

(Section 13.2). Soil monitoring and sampling methods

for relevant parameters also are presented (Section

13.3). Brief discussions of surface water, ground-water,

and vegetation monitoring are included in Sections 13.4

and 13.5. Monitoring and sampling concerns particular

to reclamation sites are discussed in Section 13.6.

State regulatory programs may have specific requirements

for monitoring sewage sludge land application sites. The

appropriate regulatory agencies should be contacted to

identify any applicable monitoring requirements.

13.2 Sewage Sludge Monitoring and

Sampling

The Part 503 requirements related to monitoring for

sewage sludge that is land applied focus primarily on

sewage sludge characterization to determine pollutant

concentration, pathogen density, and vector attraction

reduction. Required monitoring includes:

• Monitoring of sewage sludge for 10 pollutants (As,

Cd, Cr, Cu, Pb, Hg, Mo, Ni, Se, and Zn) to determine

pollutant levels in sewage sludge, compared to Part

503 pollutant limits (see Chapter 3).

• Monitoring to determine pathogen densities in sewage sludge, as described in Chapter 3.

• Monitoring to ensure that conditions for vector attraction reduction are maintained.

Table 13-1 summarizes major considerations for monitoring metals, pathogens, and vector attraction reduction in sewage sludge. Another EPA document,

Environmental Regulations and Technology: Control of

Pathogens and Vector Attraction in Sewage Sludge

(U.S. EPA, 1992), provides guidance for the monitoring,

sampling, and analysis of pathogens and vector attraction reduction efforts under Part 503 in detail and should

be consulted for further guidance. The remainder of this

section focuses on sampling and analysis of sewage

sludge for pollutants. For additional guidance on monitoring of sewage sludge for land application, see EPA’s Preparing Sewage Sludge for Land Application or Surface

Disposal: A Guide for Preparers of Sewage Sludge on the

Monitoring, Record Keeping, and Reporting Requirements

of the Federal Standards for the Use or Disposal of Sewage Sludge, 40 CFR Part 503 (U.S. EPA, 1993).

13.2.1 Sampling Location

Sewage sludge samples must be representative of the

final sewage sludge that is land applied. To achieve this

goal, samples must be representative of the entire

amount of sewage sludge being sampled, collected after

the last treatment process, and taken from the same,

correct location each time monitoring is performed.

Sampling locations should be as close as possible to the

stage before final land application. Liquid sewage

sludge can be sampled at the wastewater treatment

plant from pipelines, preflushed pipeline ports, or lagoons. Dewatered sewage sludge can be sampled at a

wastewater treatment plant from conveyors, front-end

loaders moving a pile of sewage sludge, or during truck

loading or unloading. At a land application site, dewatered samples can also be taken on the ground after

unloading but preferably before application, or possibly

after spreading.1

 Table 13-2 identifies recommended

sampling points for various types of sewage sludge.

1 Sampling after spreading poses the risk of penalties if samples

exceed Part 503 pollutant limits and pathogen densities or do not

comply with the regulation’s vector attraction reduction requirements. Sampling after spreading should only be done if parameters

of concern do not vary greatly in concentration and are known to fall

well below Part 503 limits.

147
Table 13-1. Monitoring Considerations for Part 503 Requirements

Parameter Validity of Analytical Data Over Time and When Sampling/Analysis Must Occur

Metals

Metals Data remain valid. 

Determine monitoring frequency in accordance with monitoring frequency requirements.

Pathogens Class A

Applies to All Class A Pathogen

Reduction Alternatives (PRA):

Fecal Coliform & Salmonella sp.

Because regrowth of fecal coliform and Salmonella sp. can occur, monitoring should be done:

(a) at the time of use or disposal, or, 

(b) when sewage sludge is prepared for sale or give-away in a bag or other container for land

application, or

(c) when sewage sludge is prepared to meet EQ requirements.

Additional Information on Each Class A Pathogen Category

Class A PRA 1: 

Thermal Treatment, Moisture,

Particle Size & Time Dependent

Data remain valid.

Time, temperature, and moisture content should be monitored continuously to ensure effectiveness

of treatment.

Class A PRA 2: 

High pH, High Temperature

Monitor to ensure that pH 12 (at 25°C) is maintained for more than 72 hours for all sewage sludge.

Class A PRA 3: 

Enteric Virus & Viable Helminth

Ova to Establish Process

Once reduced, enteric virus or viable helminth ova does not regrow. To establish a process,

determine with each monitoring episode until the process is shown to consistently achieve this

status. Then continuously monitor process to ensure it is operated as it was during the

demonstration.

Class A PRA 4: 

Enteric Virus & Viable Helminth

Ova for Unknown Process

Once reduced, enteric virus or viable helminth ova does not regrow. Monitor representative sample

of sewage sludge:

(a) at the time of use or disposal, or

(b) when prepared for sale or give-away in a bag or other container for land application, or

(c) when prepared to meet EQ requirements.

Class A PRA 5:

PFRP

Monitor at sufficient frequency to show compliance with time and temperature or irradiation

requirements.

Class A PRA 6:

PFRP Equivalent

Monitor at sufficient frequency to show compliance with PFRP or equivalent process requirements.

Pathogens Class B

Class B PRA 1:

Fecal Coliform

Measure the geometric mean of 7 samples at the time the sewage sludge is used or disposed.

Class B PRA 2: Monitor at sufficient frequency to show that the PSRP requirements are met.

Class B PRA 3: Monitor at sufficient frequency to show that the equivalent PSRP requirements are met.

Vector Attraction Reduction

Vector Attraction Reduction (VAR) 1:

38% Volatile Solids

Reduction (VSR)

Once achieved, no further attractiveness to vectors. Follow Part 503 frequency of monitoring

requirements.

VAR 2:

for Anaerobic Digestion:

Lab Test

VAR 3:

for Aerobic Digestion:

Lab Test

VAR 4:

SOUR Test for

Aerobic Processes

Once achieved, no further attractiveness to vectors. Follow Part 503 frequency of monitoring

requirements.

VAR 5:

Aerobic >40°C

Monitor at sufficient frequency to show that sewage sludge is achieving the necessary temperatures

over time.

VAR 6:a

Adding Alkali

Determine pH over time. Data are valid as long as the pH does not drop such that putrefaction

begins prior to land application.

148
13.2.2 Frequency of Monitoring

The Part 503 regulation establishes minimum frequency of monitoring requirements for sewage sludge

that is land applied based on the amount of sewage

sludge applied at a site in a year, as discussed in Chapter 3 and shown in Table 3-15. The permitting authority

may require increased frequency of monitoring if certain

conditions exist, such as if no previous sampling data

are available on the sewage sludge to be land applied

or if pollutant concentrations or pathogen densities vary

significantly between measurements. The permitting

authority also may reduce the frequency of monitoring to

a minimum of once annually if certain conditions exist (i.e.,

after two years, the variability of pollutant concentrations

or pathogen density is low and compliance is demonstrated).

Permitting requirements regarding frequency of monitoring may differ depending on whether sewage sludge is

continuously land applied or is stored prior to land application, to ensure collection of a representative sample

of the sewage sludge that is actually land applied.

VAR 7:a

Moisture Reduction

No Unstabilized

Primary Solids

To be achieved only by the removal of water. VAR 7 has been achieved as long as the moisture

level remains below 30%.

VAR 8:a

Moisture Reduction

Primary Unstabilized

Solids

To be achieved only by the removal of water. VAR 8 has been achieved as long as the moisture

level remains below 10%.

VAR 9:b

Injection into Soil

No significant amount of sewage sludge remains on soil surface within 1 hour after injection.

VAR 10b:

Incorporation into Soil

Sewage sludge must be incorporated into soil within 6 hours after being placed on the soil surface.

VAR 11b:

Covered with Soil

(Surface Disposal Only)

Surface disposed sewage sludge must be covered daily.

VAR 12b:

Domestic Septage

pH Adjustment

Preparer must ensure that pH is 12 for more than 30 minutes for every container of domestic

septage treated with alkali.

a

 EPA is proposing that requirements for options 6, 7, and 8 be met at the time of use or disposal.

b

 Conditions for options 9-12 must be maintained at all times if one of these options is chosen to meet vector attraction reduction requirements.

Table 13-1. (continued)

Table 13-2. Sampling Points for Sewage Sludge

Sewage Sludge Type Sampling Point

Anaerobically Digested Collect sample from taps on the discharge side of positive displacement pumps.

Aerobically Digested Collect sample from taps on discharge lines from pumps. If batch digestion is used, collect sample

directly from the digester. Cautions:

1. If biosolids are aerated during sampling, air entrains in the sample. Volatile organic compounds may

be purged with escaping air.

2. When aeration is shut off, solids may settle rapidly in well-digested sewage sludge.

Thickened Collect sample from taps on the discharge side of positive displacement pumps.

Heat Treated Collect sample from taps on the discharge side of positive displacement pumps after decanting. Be

careful when sampling heat-treated sewage sludge because of:

1. High tendency for solids separation.

2. High temperature of sample (temperature < 60°C as sampled) can cause problems with certain

sample containers due to cooling and subsequent contraction of entrained gases.

Dewatered, Dried, Composted Collect sample from material collection conveyors and bulk containers. Collect sample from many

locations within the sewage sludge mass and at various depths.

Dewatered by Belt Filter Press,

Centrifuge, Vacuum Filter Press

Collect sample from sewage sludge discharge chute.

Dewatered by Sewage Sludge

Press, (plate and frame)

Collect sample from the storage bin; select four points within the storage bin, collect equal amount of

sample from each point and combine.

Dewatered by Drying Beds Divide bed into quarters, grab equal amounts of sample from the center of each quarter and combine to

form a composite sample of the total bed. Each composite sample should include the entire depth of

the sewage sludge material (down to the sand).

Compost Piles Collect sample directly from front-end loader while sewage sludge is being transported or stockpiled

within a few days of use.

149
13.2.3 Sample Collection

Liquid sewage sludge from pipelines should be sampled

as far downstream as possible to take advantage of

maximum mixing, thus reflecting the most representative

sample of sewage sludge to be land applied. If liquid

sewage sludge must be sampled from a lagoon, floating,

suspended, and sediment layers should be included in

the sample.

For dewatered sewage sludge (10% to 40% solids),

sampling is best done when the sewage sludge is being

moved to maximize representativeness. A convenient

way to collect samples might be to sample haul truck

loads at a frequency that obtains the minimum number

of samples needed, as required by the frequency of

monitoring specified in the Part 503 regulation. This

frequency can be determined by dividing the annual

tonnage or cubic yards of sewage sludge by the calculated number of samples to determine how often haul

trucks or spreaders should be sampled. For example, if

250 cubic yards of sewage sludge are hauled to the site

annually in haul trucks with a 25-cubic-yard capacity,

and if 10 samples are required, then one composite grab

sample from every truck load might suffice, or several

samples from each truckload might be needed to obtain

a representative sample. If half that amount was hauled

in a year, then two composite grab samples representing

the front and back half of each truck would be needed.

If the amount of sewage sludge requires more truck

loads than samples, then samples would be taken of the

required percentage of loads to obtain the requisite

number of samples.

Other EPA documents (U.S. EPA, 1989, 1993, 1994)

provide more detailed guidance on specific procedures

for collecting sewage sludge samples.

Sample collection and handling procedures should be

clearly defined and consistently followed to minimize

sample errors attributable to the sampling process. This

can be accomplished with a written sampling protocol

that includes:

• Specification of personnel responsible for collecting

samples, and training requirements to ensure that the

sampling protocol is correctly followed.

• Specification of safety precautions to prevent exposure of sampling personnel to pathogenic organisms,

such as use of gloves when handling or sampling

untreated or treated sewage sludge and cleaning of

sampling equipment, containers, protective clothing,

and hands before delivering samples to others.

• Identification of the appropriate type of sampling device. For liquid sewage sludge, certain types of plastic (e.g., polyethylene) or glass (e.g., non-etched

Pyrex) may be appropriate, depending on the type of

sample (e.g., metals or pathogens); coliwasas can be

used for sampling liquid sewage sludge from lagoons. For dewatered sewage sludge, soil sampling

devices, such as scoops, trier samplers, augers, or

probes can be used. If steel devices are used, stainless steel materials are best; chrome-plated samplers

should be avoided.

• Description of sample mixing and subsampling procedures when grab samples of sludge are composited and only part of the composite sample is used

for analysis. This usually requires use of a mixing

bowl or bucket (stainless steel or Teflon) or a disposable plastic sheet on which samples can be mixed

and from which a smaller sample can be taken.

• Specification of the size and material of sample containers. Table 13-3 identifies suitable containers and

minimum volume requirements for sludge sampling.

Sample containers can often be obtained from the

person or laboratory responsible for doing the sample

analysis.

• Specification of sample preservation procedures and

sample holding times. Table 13-3 identifies these requirements for sludge samples. The appropriate

regulatory agency, in coordination with the testing

laboratory, should be contacted to identify any required sample preservation procedures and holding

times for all constituents being monitored.

• Specification of sample equipment cleaning procedures to ensure that cross-contamination of samples

does not occur. ASTM D5088 (Standard Practice for

Decontamination of Field Equipment Used at Nonradioactive Waste Sites) provides guidance on these

procedures.

• Specification of types and frequency of quality assurance/quality control (QA/QC) samples. Again, the appropriate regulatory agency should be contacted to

determine which types of QA/QC samples may be

required for the site.

• Description of sample chain-of-custody procedures to

ensure that the integrity of samples is maintained

during transport and analysis of samples.

13.2.4 Analytical Methods

Table 13-4 identifies analytical methods for pathogens,

inorganic pollutants, and other sewage sludge parameters that are required by the Part 503 regulation. Specific

methods for sewage sludge sample preparation and

analysis for metals of interest are contained in Test

Methods for Evaluating Solid Waste (U.S. EPA, 1986).

13.3 Soil Monitoring and Sampling

Soil sampling and analysis for constituents affecting

plant growth (see Chapter 6) may be needed to ensure

150
Table 13-3. Sewage Sludge Sample Containers, Preservation, and Storage

Parameter

Wide-Mouthed

Container Preservativea Maximum Storage Timea Minimum

Volumeb

Metals

Solid and semi-solid

samples

P, G Cool, 4°C 24 hours 300 mL

Mercury (liquid) P, G HNO3 to pH < 2 28 days 500 mL

All other liquid metals P, G HNO3 to pH < 2 6 months 1,000 mL

Pathogen Density and Vector Attraction Reduction

Pathogens G, P, B, SS 1. Cool in ice and water to <10°C

if analysis delayed >1 hr, or

2. Cool promptly to < 4°C, or

3. Freeze and store samples to

be analyzed for viruses at 0°

Cd

6 hours

(bacteria)

24 hours (bacteria and viruses)

1 month (helminth ova)

2 weeks

1-4 litersc

Vector attraction

reduction

Variesb Variesb 1-4 litersc

a

 Preservatives should be added to sampling containers prior to actual sampling episodes. Storage times commence upon addition of sample

to sampling container. Shipping of preserved samples to the laboratory may be, but is generally not, regulated under Department of

Transportation hazardous materials regulations. b

 Varies with analytical method. Consult 40 CFR Part 503. For dry sewage sludge, convert to dry weight (DW). DW = wet 4 percent solids. c

 Reduced at the laboratory to approx. 300 mL samples.

d

 Do not freeze bacterial or helminth ova samples.

P = Plastic (polyethylene, polypropylene, Teflon)

G = Glass (non-etched Pyrex)

B = Presterilized bags (for dewatered or free-flowing biosolids)

SS= Stainless steel (not steel- or zinc-coated)

Table 13-4. Analytical Methods for Sewage Sludge Samplinga

Sample Type Method

Enteric Viruses ASTM Designation: D 4994-89, Standard Practice for Recovery of Viruses from

Wastewater Sludges, Annual Book of ASTM Standards: Section 11. Water and

Environmental Technology, ASTM, Philadelphia, PA, 1992.

Fecal Coliform Part 9221 E or Part 922 D, Standard Methods for the Examination of Water and

Wastewater, 18th edition, American Public Health Association, Washington, DC, 1992.

Helminth Ova Yanko, W.A., Occurrence of Pathogens in Distribution and Marketing Municipal Sludges,

EPA/600/1-87/014, 1987. PB 88-154273/AS, National Technical Information Service,

Springfield, VA; (800) 553-6847.

Inorganic Pollutants Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, EPA Publication

SW-846, 3rd edition (1986) with Revision I. 2nd edition. PB 87-120291, National

Technical Information Service, Springfield, VA. 3rd edition Doc. No. 955-001-00000-1,

Superintendent of Documents, Government Printing Office, Washington, DC.

Salmonella sp. Bacteria Part 9260 D, Standard Methods for Examination of Water and Wastewater, 18th edition,

American Public Health Association, Washington, DC, 1992; or, Kenner, B.A. and H.P.

Clark, Detection and Enumeration of Salmonella and Pseudomonas aeruginosa, J.

Water Pollution Control Federation, 46(9):2163-2171, 1974.

Specific Oxygen Uptake Rate Part 2710 B, Standard Methods for the Examination of Water and Wastewater, 18th

edition, American Public Health Association, Washington, DC, 1992.

Total, Fixed, and Volatile Solids Part 2540 G, Standard Methods for the Examination of Water and Wastewater, 18th

edition, American Public Health Association, Washington, DC, 1992.

Percent Volatile Solids Reduction Calculation Environmental Regulations and Technology—Control of Pathogens and Vectors in

Sewage Sludge, EPA/625/R-92/013, U.S. Environmental Protection Agency, Cincinnati,

OH, 1992; (614) 292-6717.

a

 All of these analytical methods are required by the Part 503 rule, except the Percent Volatile Solids Reduction Calculation, which is provided

as guidance in the Part 503 rule.

151
vigorous crop production. Soil monitoring is not a Part

503 requirement. As discussed in Chapter 6, soil sampling at sewage sludge land application sites is performed primarily to assist in determining soil chemical

parameters (N, P, and K) for calculation of sewage

sludge and supplemental fertilizer application rates to

supply plant nutrient requirements. Additional sitespecific analyses may be needed to monitor the status

of some land application systems. For example, soils

may need to be analyzed for soluble salts and/or boron

in semiarid regions where irrigation is planned. Table

13-5 summarizes potential surface and subsurface soil

parameters that may be useful to monitor prior to or after

sewage sludge land application. Advice should be obtained from the local University Cooperative Extension

Service, County Agricultural Agents, and/or others with

expertise in sampling and analysis of soils in the sewage

sludge land application site area.

13.3.1 Sampling Location and Frequency

Initially, soil samples can be collected from each field

where sewage sludge will be land applied. Generally, if

a given field exceeds 10 ha (25 ac), individual soil

samples should be collected from each soil series within

the field. The number and location of samples necessary

to adequately characterize soils prior to sewage sludge

land application is primarily a function of the spatial

variability of the soils at the site. If the soil types occur

in simple patterns, a composite sample of each major

type can provide an accurate picture of the soil characteristics. The site soil map described in Chapter 6 will

identify major soil types that should be sampled.

Soil pH measurements can be done in the field at relatively

low cost. Thus, measuring the pH of soil samples taken on

a grid pattern (e.g., 30 m [100 ft] sections), can serve as a

useful indicator of the degree of spatial variability within soil

map units. If pH is variable, drawing contours of equal pH

will identify subareas in a soil type where separate composite samples should be collected. Such a map also is

useful when the pH of soil needs to be adjusted.

Once initial sampling and analysis of soil samples is

completed, the frequency of subsequent sampling will

depend on land use and any state regulatory soil monitoring requirements. For agricultural crops, pH, P, and K

soil tests are typically done every two years. Monitoring

of these parameters typically is not required for forest

land application sites. As discussed in Section 13.6.3,

monitoring requirements at reclamation sites will typically

be more extensive than at agricultural and forest sites.

If sewage sludge is applied at agronomic rates to supply

plant N requirements (as is required by Part 503), periodic monitoring of soil-available N may be useful because of the difficulty in accurately predicting N

mineralization rates of sewage sludge. Annual monitoring of soil N is appropriate for irrigated crops, as well as

certain non-irrigated crops such as corn. Annual monitoring is less critical at forest sites because crops are

not removed each year, but may be performed initially

to gain an understanding of nitrogen dynamics at the

site. Section 13.3.4 further discusses test methods for

estimating N availability.

13.3.2 Number of Samples

In some states, the state regulatory agency stipulates

the minimum number of soil borings which must be

analyzed. New Jersey, for example, historically has

based the minimum number of soil borings required

based on the proposed sewage sludge land application

site area, ranging from a minimum of 3 borings on small

sites (up to 4 ha [10 ac]) to 24 borings on large sites

(over 80 ha [200 ac]. Samples taken from similar soil

horizons are usually composited for several borings located near each other in homogeneous soil. The composited samples are subsequently analyzed.

13.3.3 Sample Collection

The proper selection of tools for collection of soil samples

depends in part on the texture and consistency of the soil,

the presence or absence of rock fragments, the depth to

Table 13-5. Potential Soil Surface Layer and Subsurface

Parameters of Interest

Monitoring Prior to Sewage Sludge Application

Surface Layer Subsurface Layers

Particle size distribution Particle size distribution

pH pH

Electrical conductivity Electrical conductivity

Cation exchange capacity (CEC) Cation exchange capacity (CEC)

Lime requirement (acid soils)

Plant available P and K

Soil N parameters

NO3-N

NH4-N 

Organic matter

Organic-N

C:N ratio

Soil microbial biomass C and N

N mineralization potential

Monitoring After Sewage Sludge Application

pH pH

Electrical conductivity Electrical conductivity

Lime requirement (acid soils)

Plant available P and K

Soil N parameters

Organic matter

Organic-N

152
be sampled, and the degree of allowable soil surface

disturbance. Soil samples are most accurately taken

from a freshly dug pit. Where field plots are to be sampled periodically, however, preferable sampling tools are

those which disturb the plot the least. Cutaway soil

sampling tubes, closed cylinder augers, and tiling

spades (sharp-shooters) may be used depending on the

size of the plot and allowable disturbance. The cutaway

soil sampling tube creates the least disturbance, and

works well in the plow layer and the upper subsoil of moist,

stone-free, friable soils. Each sample collected should

represent the cross section of the soil layer being sampled.

In sampling subsurface soils, care must be taken to

remove loose particles of sewage sludge residue on the

soil surface around the hole prior to and during sampling. In addition, any surface soil/sludge residue attached to the top and side of the core samples from

lower depths should be removed by slicing with a knife.

Where cores extend below the depth of the seasonal

high water table, it is recommended that the holes be

sealed by filling with bentonite pellets and tap water. A

map showing sample points should be made.

The depth to which the soil profile is sampled and the

extent to which each horizon is vertically subdivided

depend largely on the parameters to be analyzed, the

vertical variations in soil character, and the objectives

of the soil sampling program. For initial characterization, samples are typically taken from each distinct soil horizon down to a depth of 120 to 150 cm (4

to 5 ft). For example, samples may be taken from four

soil depths (horizons) as follows: 0 to 15 cm (0 to 6 in),

15 to 45 cm (6 to 18 in), 45 to 75 cm (18 to 30 in), and

75 to 120 cm (30 to 42 in). Usually, at a minimum,

samples are taken from the upper soil layer (e.g., 0

to 15 cm [0 to 6 in]) and a deeper soil horizon (e.g., 45

to 75 cm [18 to 30 in]).

Subsequent samples for pH, P, and K monitoring are

usually confined to the surface layer at 0-15 or 0-30 cm,

depending on the thickness of the soil A horizon. Recommended sampling depths for developing NO3 profiles

generally vary from 0.6 to 1.2 m, depending on the crop

and state. These variations are based on depths known

to represent the best correlation between soil-NO3 and

crop yield in particular areas and with particular crops.

Advice should be obtained from the local University

Cooperative Extension Service, County Agricultural

Agents, and/or others with expertise in sampling and

analysis of soils in the locality of the sewage sludge land

application site concerning recommended sampling

depths for NO3 profiles. Depths up to 60 cm can usually

be collected by hand without much difficulty. Collection

of samples exceeding 60 cm usually requires use of

power-driven soil sampling equipment.

Estimation of N immobilization (see Chapter 8) associated with initial sewage sludge application at forest sites

involves sampling of forest litter to measure the amount

of C and N. Representative samples of twigs, leaves,

and partially decomposed litter on the forest floor can be

collected and weighed to determine the total amount of

litter in kg/ha. It may also be desirable to quantify the

macroorganic fraction of the soil surface (the sand-sized

fraction of soil organic matter). Gregorich and Ellert

(1993) discuss methods for measuring this fraction.

Soil samples should be air-dried (at temperatures less

than 40°C), ground, and passed through a 2-mm sieve

as soon as possible after collection. Chemical analyses

are generally performed on air-dried samples, which do

not require special preservation for most parameters.

Samples collected for nitrate, ammonia, and pathogen

analyses, however, should be refrigerated under moist

field conditions and analyzed as soon as possible.

13.3.4 Analytical Methods

Major reference sources for standard methods for physical and chemical analysis of soil samples include: Carter

(1993), Council on Soil Testing and Analysis (1992),

Klute (1986), Page et al. (1982), Soil Conservation Service (1984), and Westerman (1990).

13.3.4.1 Nitrogen

Keeney (1982) provides a summary of soil analysis

methods used in different states to develop N fertilizer

recommendations. The most commonly used methods

are: (1) NO3 profiles, and (2) measurement of soil organic matter content in the surface soil. NO3 profiles are

most commonly used in western states where crops are

grown under irrigation, but Sander et al. (1994) note that

the pre-sidedress nitrate test (PSNT) has been demonstrated to be a useful test for corn crops in more humid

climates. Measurement of organic matter content is

used by a number of states in both the eastern and

western United States to directly or indirectly estimate

mineralizable N. Missouri has refined the use of organic

matter by basing N mineralization rate estimates on soil

texture (Keeney, 1982).

Measurements of the mineralization potential of soils

and of soils amended with sewage sludge usually are

accomplished using laboratory soil column biological

incubation methods. Keeney (1982) and Campbell et al.

(1993) describe these methods. Most of the references

identified at the beginning of this section cover the wide

variety of methods that are available for determination

of organic and inorganic forms of N in soils.

153
13.3.4.2 Plant-Available Phosphorus and

Potassium

The amount of plant-available P is determined by analyzing the amount of P removed from soil by a particular

extractant. The extractant used varies in different regions of the United States, but typically is a dilute acid

or a bicarbonate solution. Essentially, all P taken up by

crops is present in insoluble forms in soils rather than

being in the soil solution. In all states, it has been

determined that there is a relationship between the

amount of extractable P in a soil and the amount of P

fertilizer needed for various yields of different crops.

Such information may be obtained from extension services or universities.

As with P, an extractant is used to determine the plantavailable K in a soil. Potassium available for plant uptake is present in the soil solution, and also is retained

as an exchangeable cation on the cation exchange

complex of the soil. The amount of plant-available K is

then used to determine the K fertilizer rate for the crop

grown. Most sewage sludge usually is deficient in K,

relative to crop needs.

13.4 Surface-Water and Ground-Water

Monitoring

The risk-based pollutant limits and the management

practices for land application specified in the federal

Part 503 rule are designed to be sufficiently protective

of surface water and ground water so that onsite water

quality monitoring usually is not required at land application sites. Some states may require surface or

ground-water monitoring for special conditions at a land

application site, as discussed below.

13.4.1 Surface-Water Monitoring

Properly designed sewage sludge land application sites are

generally located, constructed, and operated to minimize

the chance of surface-water runoff containing sewage

sludge constituents. Surface-water monitoring rarely is

required when sewage sludge is applied at agronomic

rates. In some cases, a state agency may require monitoring for special situations. In these cases, the state

usually will specify monitoring locations and procedures.

13.4.2 Ground-Water Monitoring

Sewage sludge land application at agronomic rates should

pose no greater threat of NO3

−

 contamination of ground

water than does the use of conventional N fertilizers.

Special conditions at a land application site may result in

ground-water monitoring requirements by the state. In

such cases, monitoring locations and procedures typically

will be specified by the appropriate state agency.

13.5 Vegetation Monitoring

The federal Part 503 pollutant limits and management

practices for land application specified in the Part 503

rule are designed to be sufficiently protective of vegetation regarding uptake of heavy metals so that onsite

monitoring of vegetation is not required. Vegetation

monitoring may be conducted for public relations purposes, when it is desirable to assure private crop or tree

farm owners that their crops are not being adversely

affected by the use of sewage sludge. Table 13-6 summarizes sampling procedures for field crops and pastures.

13.6 Monitoring and Sampling at

Reclamation Sites

13.6.1 General

If a land application program at a reclamation site complies

with applicable requirements, the sewage sludge will pose

little potential for adverse effects on the environment, and

no monitoring is necessary beyond the Part 503 frequency

of monitoring requirements (see Chapter 3). Some states

require monitoring at a reclamation site after the sewage

sludge has been land applied. Special monitoring and

sampling procedures may be needed for such monitoring

because of more complex site geochemistry compared

to undisturbed soils.

13.6.2 Disturbed Soil Sampling Procedures

Standard soil sampling procedures employed on agricultural fields can often be used for reclamation sites

that have had topsoil replaced. For some unreclaimed

sites, more intensive sampling may be necessary to

characterize site conditions. In heterogenous materials,

such as mine spoils, an adequate determination of conditions may require sampling on a grid pattern of approximately 30 m (100 ft) over the entire site.

Although the disturbed surface materials often are not

soil in the generic sense, soil tests on disturbed lands

have proven useful. Soil tests on drastically disturbed

sites, however, do have some limitations that should be

taken into consideration during site evaluation. Guidelines vary widely on the number of samples to be taken.

Recommendations for sampling heterogeneous strip

mine spoils in the eastern U.S. range from 4 to 25

individual samples per ha (1.5 to 10 per ac). It has also

been suggested that one composite sample made up

of a minimum of 10 subsamples for each 4 ha (10 ac)

area may be adequate (Barnhisel, 1975). Many disturbed lands are not heterogeneous, however, and the

range and distribution of characteristics of the surface

material often is more important than the average composition. In general, it is recommended that material

that is visibly different in color or composition should

154
be sampled as separate units (areas) if large enough

to be treated separately in the reclamation program.

13.6.3 Suggested Monitoring Program

13.6.3.1 Background Sampling (Prior to Sewage

Sludge Application)

Composite sewage sludge samples can be collected

and analyzed to provide data for use in designing loading rates. Composite soil samples can be collected from

the site to determine pH, liming requirements, CEC,

available nutrients, and trace metals prior to sewage

sludge addition.

13.6.3.2 Sampling During Sewage Sludge

Application

When the sewage sludge is delivered, grab samples can

be taken and analyzed for moisture content if there is

variation in the moisture content of the sewage sludge.

Composite sewage sludge samples also should be collected to assist in documenting the actual amounts of

nutrients applied to the site (and trace metal amounts

applied, if Part 503 CPLR pollutant limits are being met,

see Chapter 3).

13.6.3.3 Post-Sewage Sludge Application

Monitoring

Monitoring of the sewage sludge application site after

the sewage sludge has been applied can vary from none

to extensive, depending on state and local regulations

and site-specific conditions. Generally, it is desirable to

analyze the soil after 1 year for soil pH changes. In

addition, periodic surface and ground water analysis

may be useful to document any long-term changes in

water quality.

Some states have very specific requirements for monitoring, and the designer should consult the appropriate

regulatory agency. Monitoring requirements by the State

of Pennsylvania (Pennsylvania Department of Environmental Resources, 1988) provide an example:

Table 13-6. Suggested Procedures for Sampling Diagnostic Tissue of Crops (Walsh and Beaton, 1973)

Crop Stage of Growtha Plant Part Sampled

Number

Plants/Sample

Corn Seedling

Prior to tasseling

From tasseling to silking

All the aboveground portion.

Entire leaf fully developed below whorl.

Entire leaf at the ear node (or immediately

above or below).

20-30

15-25

15-25

Soybeans and other beans Seedling 

Prior to or during early flowering

All the aboveground portion.

Two or three fully developed leaves at top of

plant.

20-30

20-30

Small grains Seedling

Prior to heading

All the aboveground portion.

The 4 uppermost leaves.

50-100

50-100

Hay, pasture or forage grasses Prior to seed emergence The 4 uppermost leaf blades. 40-50

Alfalfa, clover and other legumes Prior to or at 1/10 bloom Mature leaf blades taken about 1/3 of the way

down the plant.

40-50

Sorghum-milo Prior to or at heading Second leaf from top of plant. 15-25

Cotton Prior to or at 1st bloom, or at 1st

square

Youngest fully mature leaves on main stem. 30-40

Potato Prior to or during early bloom 3rd to 6th leaf from growing tip. 20-30

Head crops (e.g., cabbage) Prior to heading 1st mature leaves from center of whorl. 10-20

Tomato Prior to or during early bloom stage 3rd or 4th leaf from growth tip. 10-20

Beans Seedling

Prior to or during initial flowering

All the aboveground portion.

2 or 3 fully developed leaves at the top of plant.

20-30

20-30

Root crops Prior to root or bulb enlargement Center mature leaves. 20-30

Celery Mid-growth (12-15 in. tall) Petiole of youngest mature leaf. 15-30

Leaf crops Mid-growth (12-15 in. tall) Youngest mature leaf. 35-55

Peas Prior to or during initial flowering Leaves from 3rd node down from top of plant. 30-60

Melons Prior to fruit set Mature leaves at base of plant on main stem. 20-30

a

 Seedling stage signifies plants less than 12 in. tall.

155
The Pennsylvania Department of Environmental

Resources (DER) requires a ground-water

monitoring system on mine land amended with

sewage sludge. The system must consist of the

following, at a minimum: (1) at least one

monitoring well at a point hydraulically

upgradient in the direction of increasing static

head from the area in which sewage sludge has

been applied; (2) at least three monitoring wells

at points hydraulically downgradient in the

direction of decreasing static head from the area

treated with sewage sludge; and (3) in addition to

the three wells, the DER may allow one or more

springs for monitoring points if the springs are

downgradient from the treated sewage sludge

area. Surface water monitoring points may also

be required by the DER if appropriate for the

specific site.

Ground-water samples must be collected and

analyzed at required frequencies for various

parameters, including Kjeldahl nitrogen,

ammonia-nitrogen, nitrate-nitrogen; certain metals,

organics, and other water quality indicators; and

ground-water elevation in monitoring wells. The

DER may also require soil-pore water monitoring

using lysimeters located in the unsaturated zone

within 36 inches of the soil surface. Soil sampling

for certain metals, pH, and phosphorus using

DER procedures is required for mine reclamation

sites that may be used for agriculture. For crops

grown for animal consumption, the DER may

require a crop analysis, usually for certain

specified metals.

13.7 References

When an NTIS number is cited in a reference, that

document is available from:

 National Technical Information Service

 5285 Port Royal Road

 Springfield, VA 22161

 703-487-4650

Barnhisel, R. 1975. Sampling surface-mined coal spoils. Department

of Agronomy Report AGR-41, University of Kentucky, Lexington, KY.

Campbell, C., B. Ellert, and Y. Jame. 1993. Nitrogen mineralization

potential in soils. In: Carter, M.R., ed. Soil sampling and methods

of analysis. Lewis Publishers, Boca Raton, FL, pp. 341-349.

Carter, M., ed. 1993. Soil sampling and methods of analysis. Lewis

Publishers, Boca Raton, FL.

Council on Soil Testing and Analysis. 1992. Reference methods for

soil analysis. Georgia University Station, Athens, GA.

Gregorich, E. and B. Ellert. 1993. Light fraction and macroorganic

matter in mineral soils. In: Carter, M., ed. Soil sampling and methods of analysis. Lewis Publishers, Boca Raton, FL, pp. 397-407.

Keeney, D. 1982. Nitrogen-availability indices. In: Page, A.L., ed.

Methods of soil analysis, part 2, 2nd ed. American Society of

Agronomy, Madison, WI, pp. 711-733.

Klute, A., ed. 1986. Methods of soil analysis, part 1: Physical and

mineralogical methods, 2nd edition. Agronomy Monograph No. 9,

American Society of Agronomy, Madison, WI.

Page, A., R. Miller, D. Keeney, eds. 1982. Methods of soils analysis,

part 2—Chemical and microbiological properties, 2nd edition. ASA

Monograph 9, American Society of Agronomy, Madison, WI.

Pennsylvania Department of Environmental Resources. 1988. Land

application of sewage sludge. In: Pennsylvania Code, Title 25,

Chapter 275.

Sander, D., D. Walthers, and K. Frank. 1994. Nitrogen testing for

optimum management. Journal of Soil and Water Conservation

49(2):46-52.

Soil Conservation Service (SCS). 1984. Procedures for collecting soil

samples and methods of analysis for soil survey. Soil Survey

Investigations Report No. 1, U.S. Government Printing Office.

U.S. EPA. 1994. A plain English guide to the EPA Part 503 biosolids

rule. EPA/832/R-93/003. Washington, DC.

U.S. EPA. 1993. Preparing sewage sludge for land application or

surface disposal: A guide for preparers of sewage sludge on the

monitoring, record keeping, and reporting requirements of the federal standards for the use or disposal of sewage sludge, 40 CFR

Part 503. EPA/831/B-93/002a. Washington, DC.

U.S. EPA. 1992. Environmental regulations and technology: Control of

pathogens and vector attraction in sewage sludge. EPA/625/R92/013. Washington, DC.

U.S. EPA. 1989. POTW sludge sampling and analysis guidance document. NTIS PB93227957. Washington, DC.

U.S. EPA. 1986. Test methods for evaluating solid waste, 3rd ed.

EPA/530/SW-846 (NTIS PB88239223). Current edition and updates available on a subscription basis from U.S. Government

Printing Office, Stock #955-001-00000-1.

Walsh, L. and J. Beaton, eds. 1973. Soil testing and plant analysis.

Soil Science Society of America, Madison, WI.

Westerman, R., ed. 1990. Soil testing and plant analysis, 3rd edition.

Soil Science Society of America, Madison, WI.

156
Chapter 14

General Design Considerations

14.1 Introduction

This chapter provides guidance for designing the components of a land application system, including:

• Sewage sludge transport systems

• Sewage sludge storage

• Land application methods

• Site preparation

• Supporting facilities

The designer should take into consideration each component’s impact on overall system efficiency, reliability,

and cost when selecting and designing each of these

individual components of a land application system. For

example, the most economical sewage sludge transportation method may not result in the lowest overall system

cost because of associated high costs at the treatment

plant and/or land application site.

14.2 Transportation of Sewage Sludge

14.2.1 Transport Modes

Efficient transport of sewage sludge should be a key

design consideration. Potential modes of sewage sludge

transportation include truck, pipeline, railroad, or various

combinations of these three modes (Figure 14-1).

The method of transportation chosen and its costs depend on a number of factors, including:

• Characteristics and quantity of the sewage sludge to

be transported.

• Distance from the treatment works to the application

site(s).

• Availability and proximity of the transportation mode(s)

to both origin and destination (e.g., roads, proximity

of railroad spurs).

• Degree of flexibility required in the transportation

method chosen.

• Estimated useful life of the land application site based

on site characteristics (e.g., topography, vegetative

cover, soil type, area available).

• Environmental and public acceptance factors.

To minimize the danger of spills, liquid sewage sludge

should be transported in closed tank systems. Stabilized, dewatered sewage sludge can be transported in

open vessels, such as dump trucks and railroad gondolas if equipped with watertight seals and anti-splash

guards.

14.2.2 Vehicle Transport

14.2.2.1 Vehicle Types Available

Trucks are widely used for transporting both liquid and

dewatered sewage sludge and are generally the most

flexible means of transportation. Terminal points and haul

routes can be readily changed with minimal cost. Trucks

can be used for hauling sewage sludge either to the final

application site(s) or to an intermediate transfer point

such as railroad yards. Access to sewage sludge within

a treatment plant is usually adequate for truck loading.

Many truck configurations are available, ranging from

standard tank and dump bodies to specialized equipment

for hauling and spreading sewage sludge. Depending on

the type of sewage sludge to be hauled, different types

of vehicles can be used, as described below.

Liquid Sewage Sludge

The following types of vehicles can be used to haul liquid

sewage sludge (usually less than 10 percent solids, dry

weight):

• Farm tractor and tank wagon, such as those used for

livestock manure. Normally used only for short hauls

and by small rural communities.

• Tank truck, available in sizes from 2,000 to 24,000 L

(500 to 6,000 gal).

– Tank truck adapted for field application of sewage

sludge in addition to road hauling.

– Tank truck used for road hauling to the land application site(s), with sewage sludge subsequently

transferred to a field application vehicle or an irrigation system. Such tank trucks are often termed

“nurse trucks.”

157
Dewatered or Composted Sewage Sludge

The following types of vehicles can be used to haul

dewatered or composted sewage sludge (usually 20 to

60 percent solids, dry weight):

• Dump truck, available in sizes from 6 to 23 m3 (8 to

30 yd3

).

• Hopper (bottom dump) truck, available in sizes from

12 to 19 m3

 (15 to 25 yd3).

• Either of the above types of trucks can be used for

hauling the sewage sludge to the land application

site(s) and can also be adapted to spread sewage

sludge.

Figure 14-2 shows photographs of some of the types of

trucks listed above.

14.2.2.2 Vehicle Size and Number Required

To properly assess the size and number of vehicles

needed for transporting sewage sludge from the treatment plant to the application site(s), the following factors

should be considered:

• Quantity of sewage sludge, both present and future.

• Type of sewage sludge—liquid or dewatered/composted.

• Distance from treatment plant to application site(s)

and travel time.

• Type and condition of roads to be traversed, including

maximum axle load limits and bridge loading limits.

• Provisions for vehicle maintenance.

• Scheduling of sewage sludge application. In many

areas, significant seasonal variations exist (due to

weather, cropping patterns, etc.) regarding the quantity of sewage sludge that can be applied. The transport system capacity should be designed to handle

the maximum anticipated sewage sludge application

period, taking into consideration any interim sewage

sludge storage capacity available.

• Percent of time when the transport vehicles will be in

productive use. A study (U.S. EPA, 1977a) of trucks

hauling sewage sludge at 24 small to medium size

Figure 14-1. Examples of sewage sludge transportation modes to land application sites.

Figure 14-2a. A 6,500-gallon liquid sludge tank truck (courtesy

of Brenner Tank Company).

Figure 14-2b. A 3,300-gallon liquid sludge tank truck with

2,000-gallon pup trailer (courtesy of Brenner

Tank Company).

158
communities showed that trucks hauling liquid sewage

sludge were in productive use an average of 48 percent

of the time (range of 7 to 90 percent) based on an

8-hour day and 5-day week. Average use for trucks

hauling dewatered sewage sludge was reported at 29

percent.

Tables 14-1 and 14-2 provide guidelines for estimating

the number of trucks needed for transporting liquid and

dewatered sewage sludge, respectively. While the tables provide a means for making preliminary comparisons,

they are only a starting point in the decisionmaking process for a specific project. For example, the tables can

be used to quickly compare vehicle needs as a function

of whether liquid sewage sludge at 5 percent solids or

an equivalent quantity of dewatered sewage sludge at

25 percent solids will be transported. Assuming a liquid

sewage sludge quantity of 57 million L/yr (15 Mgal/yr,

which corresponds to 58,000 metric tons/yr or 64,000

Tons/yr) compared with an equivalent quantity of dewatered sewage sludge of 11,470 m3

/yr (15,000 yd3/yr,

which corresponds to 12,000 metric tons/yr or 13,000

Tons/yr). Also assume a one-way distance of 32 km (20

mi) from the treatment plant to the application site.

Tables 14-1 and 14-2 indicate that for an 8 hr/day operation, approximately six 9,450 L (2,500 gal) tank trucks

are necessary to transport the liquid sewage sludge, while

only one 11.5 m3

 (15 yd3) truck is necessary to transport

the dewatered sewage sludge. The difference in fuel

purchase would be 202,000 L/yr (53,500 gal/yr) for the

liquid sewage sludge versus 50,300 L/yr (13,300 gal/yr)

for the dewatered sewage sludge; driver time required

for the liquid sewage sludge would be 15,500 hr/yr

versus 2,600 hr/yr for the dewatered sewage sludge.

The savings in transportation costs for dewatered sewage sludge versus liquid sewage sludge can then be

compared to the cost of dewatering the sewage sludge.

The reader should be aware that the above example is

highly simplified in that it assumes that the sewage

sludge transport operation takes place 360 days a year,

allows an average of only 10 percent for labor hours

beyond actual truck operating hours, provides for only 2

hr/day for truck maintenance time, and gives no consideration to effects of sewage sludge type on operating

costs at the application site(s).

14.2.2.3 Other Truck Hauling Considerations

The haul distance should be minimized to reduce costs,

travel time, and the potential for accidents on route to

the application site(s). Factors such as unfavorable topographic features, road load limits, and population patterns may influence routing so that the shortest haul

distance may not be the most favorable.

Effective speed and travel time can be estimated from

the haul distance, allowing for differences in speed for

various segments of the route and the anticipated traffic

conditions. Periods of heavy traffic should be avoided

from a safety standpoint, for efficiency of operation, and

for improved public acceptability.

The existing highway conditions must be considered in

the evaluation of truck transport. Physical constraints,

such as weight, height, and speed limits, may limit truck

transport and will influence vehicle and route selection.

Local traffic congestion and traffic controls will influence

routing and also should be considered in determining

the transport operation schedule. Public opinion on the

use of local roadways, particularly residential streets,

may have a significant effect on truck transport operations and routing.

Fuel availability and costs can have a profound impact

on the operation and economy of sewage sludge hauling

activities. Larger trucks tend to be more fuel efficient

than smaller ones. Also, short haul distances over flat

terrain will have lower fuel requirements than long haul

distances over hills.

Truck drivers and mechanics as well as loading and

unloading personnel will be required for large sewage

sludge hauling operations. Small operations may combine these roles into one or two persons. Manpower

requirements can be determined from the operating

schedule.

Figure 14-2d. A 12-cubic-yard dewatered sludge spreader vehicle (courtesy of Ag-Chem Equipment Company).

Figure 14-2c. A 25-cubic-yard dewatered sludge haul truck

(courtesy of Converto Manufacturing Company).

159
Table 14-1. Truck Operation Summary, Liquid Sludge (Ettlich, 1976)

160
Table 14-2. Truck Operation Summary, Dewatered Sludge (Ettlich, 1976)

161
Hauling Schedule

The operating schedule for sewage sludge hauling can

be simple or very complex. An example of a simple

hauling operation would be a case where all the sewage

sludge generated each day is hauled to a reclamation

site and discharged into a large capacity sewage sludge

storage facility. In such a simple case, the designer can

easily develop an operating schedule for sewage sludge

hauling based on:

• Quantity of sewage sludge to be hauled.

• Average round-trip driving time required.

• Sewage sludge loading and unloading time required.

• Truck maintenance downtime.

• Estimated truck idle time and maintenance downtime.

• Haul truck capacity.

• Length of working shifts and number of laborers (e.g.,

drivers).

• Safety factor for contingencies (e.g., variations in

sewage sludge quantity generated; impassible roads

due to weather).

In contrast to the simple case described above, the

development of a complex sewage sludge hauling

schedule for an agricultural land application program

may involve many privately owned sites. Such a program is complicated by the need to take into account the

following additional factors:

• The variation in distance (driving time) from the treatment works to the privately owned farms accepting

the sewage sludge.

• Existence or absence of sewage sludge storage capacity provided at the application sites.

• Weather, soil conditions, and cropping patterns that

may significantly limit the number of days and locations for sewage sludge application at the sites.

An example of the large variations in sewage sludge

hauling schedules for a complex agricultural land application program is shown in Table 14-3, which indicates

the projected monthly sewage sludge distribution for the

Madison, Wisconsin, “Metrogro” project. Table 14-3

shows that projected utilization is highest during the

spring, summer, and fall months (e.g., April through

October), whereas sludge is not applied during any of

the winter months (December through March). The designer should provide for the necessary sewage sludge

transport, application, equipment, and labor to handle

the maximum sewage sludge distribution months. This

heavy scheduling, however, then results in underutilization of equipment during the low demand distribution

months, as well as the potential problem of shifting

employees to other productive work. Some municipalities have supplemented their basic needs with private

haulers during peak periods to help overcome this problem.

Contract Hauling Considerations

Many municipalities, both large and small, use private

contractors for hauling sewage sludge and sometimes

for application of sewage sludge as well. For example,

a contract operator transports, applies, and incorporates

dewatered sewage sludge from the Atlantic Wastewater

Treatment Plant in Virginia Beach, Virginia, to privately

owned farmland. Incorporation is handled by the contractor because the farmers were not incorporating the

sewage sludge promptly (Jacobs et al., 1993).

The economic feasibility of private contract hauling versus use of publicly owned vehicles and public employees should be analyzed for most new projects. If a

private contractor is used, it is essential that a comprehensive contract be prepared that includes a total management plan and avoids municipality liability for

mistakes made by the contractor. At a minimum, the

contract should cover the following responsibilities:

• Liability and insurance for equipment and employees.

• Safety and public health protection procedures and

requirements.

• Estimated sewage sludge quantities and handling

procedures.

• Responsibility and methods for handling citizen complaints and other public relations.

• Procedures for accidents, spills, and violation notification and mitigation.

Table 14-3. Projected Monthly Sludge Distribution for

Agricultural Sludge Utilization Program, Madison,

Wisconsin (Taylor, 1994)

Month % of Annual

Gal/Month

(x 1000) Gal/Day*

January 0 0 0

February 0 0 0

March 0 0 0

April 10.2 2,950 147,600

May 19.7 5,700 285,000

June 5.2 1,500 75,000

July 5.9 1,700 85,000

August 14.1 4,100 205,000

September 17.2 5,000 250,000

October 18.6 5,400 270,000

November 9.1 2,650 132,000

December 0 0 0

*Based on 20-day/month operation

Metric conversion: 1 gal = 3.78 L

162
• Monitoring procedures, record keeping, and reporting

requirements (see Chapter 13 for monitoring needs

and Chapter 15 for recordkeeping and reporting required by the Part 503 regulation).

• Responsibility for obtaining and maintaining permits,

licenses, and regulatory agency approvals.

• Standard legal provisions for non-performance relief,

termination, etc.

In some instances, sewage sludge is hauled away from

the treatment works or other facility generating or preparing sewage sludge by the user (e.g., farmer, commercial forest grower). Again, the municipality should

obtain competent legal council to avoid potential liability

due to negligence by the private user/hauler.

Additional Facilities Required for Hauling

Sewage sludge loading facilities at the treatment works

or other sewage sludge facility should be placed in an

accessible location. Depending on the type of sewage

sludge being hauled, hoppers, conveyor belts, or pipelines will be needed to load the trucks. Vehicle storage

and a maintenance/repair shop might be useful at the

plant site. Equipment washdown facilities and parking

should be nearby. Similar facilities for truck unloading

and related activities may be necessary at the sewage

sludge application site(s) and/or the sewage sludge

storage facility.

14.2.3 Pipeline Transport

Generally, only liquid sewage sludge of 8 percent solids

or less can be transported by pipeline (U.S. EPA, 1978).

Sewage sludge with higher solids concentrations, however, have been pumped; for example, the city of Seattle, Washington has reportedly pumped sewage sludge

containing up to 18 percent solids. Also, pipeline transport is not usually feasible if there are multiple, widely

separated land application sites. Other important factors

regarding pipeline transport include:

• Availability of land for sewage sludge application for

projected long-term periods; if an application site has

a short useful life, pipelines are not usually warranted.

• Sufficient sewage sludge volume to justify the high

capital costs of a pipeline, pump station(s), and appurtenances. Generally, municipal sewage treatment

plants sized below 19 million L/day (5 mgd) do not

generate sufficient sewage sludge volume to justify

pipeline transport unless the distance to the land application site is short, e.g., less than 3 km (2 mi).

• Existence of a relatively undeveloped and flat pipeline right-of-way alignment between the sewage treatment plant and the land application site. Constructing

a new pipeline through developed residential/commercial areas or through hilly terrain is expensive.

If factors such as those listed above are favorable,

transport of sewage sludge by pipeline often can be less

expensive than truck transport per unit volume of sewage sludge.

14.2.3.1 Pipeline Design

The effect of solids concentration on sewage sludge flow

characteristics is of fundamental importance in economically designing pipelines. Digested sewage sludge

has been observed to exhibit both newtonian and plastic

flow characteristics. Figure 14-3 shows the influence of

sludge solids concentrations on minimum velocities required for full turbulent flow through a pipeline. The

figure also indicates the frictional head loss and the

range of velocities for economical transportation. Below

approximately 5 percent solids, sewage sludge flow

exhibits newtonian flow characteristics, whereas at concentrations above 5 percent, the flow begins to exhibit

plastic flow characteristics. At a solids concentration

below 5 percent, the economics of sewage sludge transport will resemble water transport costs with respect to

frictional head loss and power requirements. The most

cost-effective pipeline design usually assumes operation just within the upper limits for newtonian flow (approximately 5.5 percent solids) (Haug et al., 1977). An

extensive discussion of head loss calculations and

equations for sewage sludge pipelines and pumping can

be found in Chapter 14 of the Process Design Manual

for Sludge Treatment and Disposal (U.S. EPA, 1979).

Various pipeline materials are used for transporting sewage sludge, including steel, cast iron, concrete, fiberglass, and PVC. For long-distance, high-pressure

sewage sludge pipelines, steel pipe is most commonly

used. Corrosion can be a severe problem unless properly considered during design. External corrosion is a

function of the pipe material and corrosion potential of

the soil, and can be controlled by a suitable coating

and/or cathodic protection system. Laboratory tests

simulating several digested sewage sludge lines have

indicated that with proper design, only moderate internal

corrosion rates should be expected in long-distance

pipelines conveying sewage sludge. If most of the grit

and other abrasive materials are removed from the digested sewage sludge, wear due to friction is not a

significant factor in pipeline design (U.S. EPA, 1979).

14.2.3.2 Pipeline Appurtenance Design

Commonly used sewage sludge pipeline appurtenances

are discussed briefly below. More extensive discussion

can be found in Chapter 14 of the Process Design Manual

for Sludge Treatment and Disposal (U.S. EPA, 1979).

163
Gauges

Pressure gauges are installed on the discharge side of

all pumps. They also may be installed on the suction

side of pumps for purposes of head determination. Protected, chemical-type gauges are generally used for

sewage sludge pumping.

Sampling Provisions

Generally, 2.5 to 3.8 cm (1 to 1-1/2 in) sampling cocks

with plug valves are provided either on the sewage

sludge pump itself or in the pipe adjacent to the pump.

Cleanouts and Drains

Sewage sludge pipelines should include separate

cleanouts and drains for easy clearance of obstructions.

Blind flanges and cleanouts should be provided at all

changes of direction of 45 degrees or more. Valved

drains should be included at all low points in the pipeline,

and pressure vacuum relief valves should be provided

at all high points in the pipeline. Minimum size at

cleanouts is 10 cm (4 in), with a 15 cm (6 in) size

preferred for access of tools.

Hose Gates

A liberal number of hose gates should be installed in the

piping, and an ample supply of flushing water under high

pressure should be available for clearing stoppages.

Measuring Sewage Sludge Quantities

Pump running time totalizers provide a simple method

of approximating the quantities of sewage sludge

pumped. For more sophisticated measurement, Venturi

meters, flow tubes, or magnetic meters with flushing

provisions can be used. Sewage sludge meters should

have provision for bypassing.

14.2.3.3 Pump Station Design

Pump stations used to pump sewage sludge through

long-distance pipelines should be carefully designed by

experienced engineers. This section is not intended to

be a comprehensive guide to design of such stations,

but rather highlights important design considerations

and provides references for more extensive information.

Important factors for designing long-distance sewage

sludge pumping stations include:

Figure 14-3. Hydraulic characteristics of sludge solids (U.S. EPA, 1977b).

164
• Characteristics of the sewage sludge (e.g., type, solids content, degree of stabilization, abrasive particle

content, viscosity).

• The choice of variable versus constant speed pumps.

• Quantity of sewage sludge, and type and capacity of

sewage sludge storage ahead of the pumps and at

the pipeline terminus.

• Pressure that the pumps must overcome, including

both pipeline friction loss and static (elevation difference) head.

• Anticipated pump station life.

• Need for future expansion of capacity (e.g., provision

of space for future pumps, power supply, piping, etc.).

• Ease of operation and maintenance.

• Need for standby reliability (i.e., how long the pump

station can be out of service for maintenance, power

failure, etc., as determined by available storage, alternate means of transport, etc.).

The type of sewage sludge most easily pumped over

long distances has the following characteristics: a solids

content below 6 percent; good stabilization (i.e., relatively low in volatile solids); a low concentration of abrasive grit; and the absence of large particles and stringy

material. Sewage sludge possessing other characteristics can be dealt with during design, but will normally

result in increased construction, operation, and/or maintenance costs. In Arizona, a high-speed centrifugal

pump is used to force dewatered sewage sludge (20

percent solids) and water into a pipe delivering the solids

to the field. The sewage sludge is then reliquified to a

solids content of 4 percent. The solids content of the

sludge at this Arizona site can be adjusted by regulating

the amount of water injected into the pump. The sewage

sludge is then pumped to the application site through a

system of fixed and movable pipes (Jacobs et al., 1993).

Maximum and minimum flow velocities are an important

consideration in pipeline design. A comparison of variable versus constant speed pumps is important for determining the flow through a pipeline. Variable speed

pumps allow for continuous operation and lower storage

requirements. Although constant speed pumping will

require more storage, it is usually more energy efficient

for peak flow dampening by equalization. For sewage

sludge transport, a flow rate of 1 m/s (3 ft/s) is a satisfactory value; slower rates can promote solids settling

and decomposition, while higher rates can cause scouring and increase head loss. Since pipelines represent a

significant investment and have long service lives, they

should be sized to permit efficient operation under existing conditions and also provide adequate capacity for

future growth.

The quantity of sewage sludge to be pumped determines the capacity of the pumps and the pump station.

Capacity is measured by the maximum sewage sludge

pumping rate required; therefore, it is desirable to provide as constant an output pumping rate as possible

over long periods each day. Ideally, the pumps will withdraw the sewage sludge from a large volume storage

facility (e.g., a digester) at a steady rate. If possible,

avoid using small storage tanks that require the pumps

to frequently start and stop. The storage facility supplying the pump with sewage sludge should have a liquid

level higher than the elevation of the pump suction

intake. Sewage sludge pumps work much more efficiently and reliably if they have a positive suction head.

The pressure that sewage sludge pumps must overcome is the elevation difference between the pump

station and the highest point of the sewage sludge

pipeline to the application site; also, friction loss exists

in the pipe and fittings at the maximum sewage sludge

pumping rate (when maximum pressure occurs). The

elevation difference (static head) is fixed by the topography of the pipeline alignment. The head loss due to

friction, however, will vary and can be expected to increase with time due to gradual deterioration of the

pipeline, buildup of internal sewage sludge deposits,

and other factors. The designer, therefore, should provide a safety factor in calculating total pressure loss due

to friction in the pipe and fittings. An excellent discussion

of sewage sludge pipeline head loss due to friction is

found in Chapter 14 of the Process Design Manual for

Sludge Treatment and Disposal (U.S. EPA, 1979).

Type and Number of Pumps

Various types of pumps are used to pump sewage

sludge, including centrifugal, torque, plunger, piston,

piston/hydraulic diaphragm, ejector, and air lift pumps.

Table 14-4 presents a matrix that provides guidance

regarding the suitability of each type of pump for handling different types of sewage sludge. Centrifugal

pumps are commonly selected for long-distance sewage sludge pumping because they are more efficient

(i.e., use less energy) and can develop high discharge

pressures. Centrifugal pumps are generally not used for

heavy, primary sewage sludge, however, because they

cannot handle large or fibrous solids. See Chapter 14 in

the Process Design Manual for Sludge Treatment and

Disposal (U.S. EPA, 1979) for a more detailed description of pump types.

The number of pumps installed in a pump station will

depend largely on the station capacity and the range in

sewage sludge volumes to be pumped. It is customary

to provide a total pumping capacity equal to the maximum expected inflow with at least one of the pumping

units out of service. In stations handling small flows, two

pumps are usually installed, with each pump capable of

165
Table 14-4. Use of Sewage Sludge Pumps (EPA, 1979)

166
meeting the maximum inflow rate. For larger stations,

the size and number of pumps should be selected so

that the range of inflow can be met without starting and

stopping pumps too frequently (Water Pollution Control

Federation, 1981).

Unless the designer is certain that future pump station

expansion will not be necessary, space, fittings, etc.,

should be provided in the pump station for future additional pumping capacity.

The design should assume that the pump station will

occasionally be inoperative due to maintenance, power

failure, etc. Sufficient storage capacity should be provided for sewage sludge, and/or standby power, to handle at least two days of pumping station shutdown.

Emergency tank truck hauling by a private firm is one

alternative that could be arranged in advance.

14.2.3.4 Decisionmaking Factors for Pipeline

Transport

Major factors to consider in an initial evaluation of sewage sludge pipeline transport include:

• Lack of flexibility compared to truck transport. The

pipeline has a fixed alignment and terminus. The land

application site must have a sufficient useful life to

justify the capital expense of the pipeline and pump

station(s).

• Sufficient sewage sludge volume generation to justify

the initial capital cost. If one or two tank trucks can

do the job instead, truck transport will often be more

cost-effective.

• Need to acquire pipeline right-of-way. Pipeline alignments that avoid right-of-way easement problems

should be evaluated. Condemnation, when necessary, is expensive and time-consuming and may

cause problems with community acceptance.

If pipeline transport is selected, the following factors

should be considered when choosing pipeline routes.

Alternate Routes

Preliminary planning should be conducted to reduce the

number of potential pipeline routes. Generally, one route

will be clearly favorable over the others; however, due

to unknown conditions, a certain amount of flexibility

should be maintained until the final design is determined. Crossings can add significantly to the cost of the

pipeline and complexity of construction. The shortest

distance with the least elevation difference and fewest

crossings should be the primary goal.

Pipeline Design

Pipeline friction losses should be minimized over the

route of the pipeline since they contribute significantly to

pumping requirements. Abrupt changes in slope and

direction should be minimized. Depending on the nature

of the sewage sludge and the characteristics of the soil,

corrosion control features should be incorporated in the

pipeline design. Frequently spaced isolation valves

should be provided to allow shutdown during repair and

in case of pipe failure.

Pumping Facilities

More than one pump station may be needed if the

pipeline distance is long. The number of pump stations

should be balanced with the size and number of pumps

required to determine the most cost-effective combination. Pumps should be appropriate for the type of sewage sludge to be pumped, and standby pumping units

must be provided.

Emergency Operation

Several days storage should be provided in case of

equipment failure. Digesters can be used for this purpose, if available. Standby power should be provided if

only one independent source of electricity to the pump

stations is available. Additional storage may be substituted for standby power under certain conditions, although continuous operation is preferable.

Excavation Condition Verification

Field tests should be used to establish or verify the

subsurface soil conditions. Borings should be taken after the pipeline route has been established but prior to

final design. The field tests should be used to isolate

areas where special design considerations are needed.

If highly unusual localized conditions exist, they should

be avoided, if possible, or additional field tests made.

Existing or planned underground utilities should be located and field-verified, if possible. If exact locations

cannot be established, the contractor should be held

responsible for locating them during construction.

Acquisition of Right-of-Way

Right-of-way easements must be acquired for pipelines

on private property. This process should be initiated in

the early stages of the project. The preferable method

is to obtain access rights on easements owned or controlled by other utilities when possible, or to negotiate

with landowners. Acquisition is a lengthy, complex procedure which should be avoided if possible.

14.2.4 Other Transport Methods

Rail car and barge transport are other possible methods

for transporting sewage sludge. These methods are

usually considered only by large cities for long-distance

transport to land application sites. In Chicago, for example, sewage sludge has been dried to over 50 percent

solids, barged, and then trucked to land application

sites (Jacobs et al., 1993). For a detailed discussion of

167
rail and barge transport, refer to Chapter 14 in the

Process Design Manual for Sludge Treatment and Disposal (U.S. EPA, 1979).

14.3 Storage of Sewage Sludge

It is important to note that in the Part 503 regulation, an

activity is considered storage if sewage sludge is placed

on land for 2 years or less. If sewage sludge remains on

land for longer than 2 years for final disposal, this land

area is considered an active sewage sludge unit and the

surface disposal requirements in Part 503 must be met,

unless the sewage sludge preparer can demonstrate

that the land on which the sewage sludge remains is not

an active sewage sludge unit, as discussed in Part

503.20(b).

14.3.1 Storage Requirements

Sewage sludge storage is necessary to accommodate

fluctuations in sewage sludge production rates, breakdowns in equipment, agricultural cropping patterns, and

adverse weather conditions which prevent immediate

application of sewage sludge to the land. Storage can

potentially be provided at either the treatment plant, the

land application site(s), or both. Chapter 15 in the Process Design Manual for Sludge Treatment and Disposal

(U.S. EPA, 1979) presents methods for estimating sewage sludge storage capacity and describes various storage facilities.

14.3.2 Storage Capacity

Storage capacity associated with land application sites

is based on the volume and characteristics of the sewage sludge and on climate considerations. In a 1993

study of 10 POTWs, most had extensive sewage sludge

storage capacities or other systems in place (Jacobs et

al., 1993). For example, a facility in Madison, Wisconsin,

has a large storage lagoon system that will soon be

replaced with new storage tanks capable of storing 6

months (18 million gallons) of sewage sludge. In Denver,

Colorado, the Metro Wastewater Reclamation District

(MWRD) currently composts about 10 percent of the

sewage sludge it produces; while composting is more

expensive than direct land application, the MWRD maintains the composting facilities to enhance the flexibility

and reliability of the land application program (Jacobs et

al., 1993).

Many states have regulations governing the provision of

storage capacity for sewage sludge at land application

sites, with requirements varying from state to state.

Indiana, for example, requires storage with a minimum

of 90-days capacity at land application sites; Michigan

requires that field storage be less than 7 days unless the

stored sludge is covered and a seepage barrier is provided; in Oklahoma, storage at a land application site is

not permitted (U.S. EPA, 1990).

14.3.2.1 Effect of Sewage Sludge Volume and

Characteristics on Storage Capacity

Storage capacity is primarily dependent on the amount

of sewage sludge needed at the land application site

and the volume of sludge received from the treatment

works. Storage capacity should be large enough to handle the volume of sludge generated during the longest

projected time interval between applications (Elliott et

al., 1990) and may need to be larger depending on

climatic factors (see below). For agricultural systems,

the time period between applications can range from 3

months to a year, whereas time spans between applications to forest land may be greater than 1 year (Elliott

et al., 1990).

The characteristics of sewage sludge also affect storage

(e.g., liquid sludge might be stored in tanks, while sludge

solids may be stockpiled). Sewage sludge characteristics vary with source, type of sewage sludge treatment, and retention time. Data on typical quantities and

characteristics of sewage sludge produced from various

treatment processes are presented in Chapter 4.

14.3.2.2 Climate Considerations for Evaluating

Sewage Sludge Storage

The designer of a land application system should consider the following climatic factors:

• Historical precipitation and temperature records for

the application site.

• Regulatory agency requirements pertinent to the land

application of sewage sludge on frozen, snow-covered, and/or wet soil.

• Ability of the sewage sludge application equipment

being used to operate on wet or frozen soil.

• Drainage characteristics of the application site and

associated effects on the time required after precipitation for the soil to dry sufficiently to accommodate

equipment.

If left uncovered, large volumes of sludge may be exposed to the elements during storage (Elliott et al.,

1990). Therefore, precipitation volume (minus evaporation) must be added to the storage area required for

sewage sludge. In addition, the Part 503 rule sets restrictions on the land application of certain types of

sewage sludge to flooded, frozen, or snow-covered

lands (see Chapter 3). Many states also have seasonal

limits on land application of sewage sludge, which

greatly influence storage requirements at land application

sites. These limits generally forbid the application of sewage sludge to saturated ground, ice- or snow-covered

ground, or during rainfall (U.S. EPA, 1990).

The effect on wet soils of heavy vehicle traffic transporting sludge from storage to application areas also should

168
be considered. The weight of vehicles may damage the

soil structure, increase the bulk density of soil, and

decrease infiltration. These changes in the physical

characteristics of soil may increase the potential for soil

erosion and surface runoff (Lue-Hing et al., 1992).

The climatic considerations that affect sewage sludge

storage capacity are greatly influenced by site-specific

factors. A review of land application system designs in

the United States indicates that sewage sludge storage

capacity ranges from a minimum of 30 days in hot, dry

climates up to 200 days in cold, wet climates.

EPA conducted a computer analysis of approximate

storage requirements for wastewater-to-land application

systems in the United States (Loehr et al., 1979), as

shown in Figure 14-4. This information is included in this

manual to show general regional variations in storage

requirements due to climate. For most sewage sludge

land application systems, the actual storage requirement will usually exceed the days shown in Figure 14-4.

14.3.2.3 Relationship Between Scheduling and

Storage

The majority of existing land application systems in the

United States are applying sewage sludge to privately

owned land. This requires a flexible schedule to conform

with local farming practices. Scheduling limitations will

result from cropping patterns, and typically the designer

will find that much of the agricultural land can only

receive sewage sludge during a few months of the year.

Applications of sewage sludge should be scheduled to

accommodate the growing season of the selected plant

species (Lue-Hing et al., 1992). The Madison, Wisconsin, program (Table 14-3), for example, applies over 80

percent of its sewage sludge to farmland during the

6-month period from May through October (Taylor,

1994).

Land application to forest sites should be scheduled to

conform with tree grower operations and the annual

growth-dormant cycle of the tree species. Land application at reclamation sites must be scheduled to conform

with vegetative seeding and growth patterns and also

with private landowners’ operational schedules. At all of

these types of sites, adequate storage capacity must be

provided to accommodate the variability in scheduling.

14.3.2.4 Calculation of Sewage Sludge Storage

Capacity Required

A simple method for estimating sewage sludge storage

capacity required involves estimating the maximum

number of days needed to store the volume of sewage

sludge generated. The estimate of the maximum number of days is based on climate and scheduling considerations discussed in the previous subsections, as well

as a safety factor. Often, the responsible regulatory

agency will stipulate the minimum number of days of

sewage sludge storage that must be provided. Calculations for this simple approach are shown below:

Assume:

1. Average rate of dry sewage sludge generated by

POTW is 589 kg/day (1,300 lb/day).

2. Average sewage sludge contains 5 percent solids.

3. One hundred days storage to be provided.

Solution:

1. 589 kg/day

0.05 = 11,780 kg/day (26,000 lb/day) of liquid

sewage sludge.

2. 11,780 kg/day = 11,780 L/day (3,116 gal/day) of liquid

sewage sludge produced.

3. 11,788 L/day × 100 days = 1.2 million L (312,000 gal)

of storage required.

A more sophisticated method for calculating sewage

sludge storage requirements is to prepare a mass flow

diagram of cumulative generation and projected cumulative application of sewage sludge to the land application site, as shown in Figure 14-5. The figure shows that

the minimum sewage sludge storage requirement for

this site is approximately 1.2 × 106

 gal (4.54 × 106 L),

which represents 84 days of sewage sludge storage

volume. The project designer should increase the minimum storage requirement by a safety factor of 20 to 50

percent to cover years with unusual weather and other

contingencies.

Even more accurate approaches can be used to calculate required sewage sludge storage volume. For example, if open lagoons are used for sewage sludge storage,

Figure 14-4. Storage days required as estimated from the use

of the EPA-1 computer program for wastewater-toland systems. Estimated storage based only on

climatic factors.

169
the designer can calculate volume additions resulting

from precipitation and volume subtractions resulting

from evaporation from the storage lagoon surface.

14.3.3 Location of Storage

In general, the following factors should be considered

when siting sewage sludge storage facilities:

• Maximize the use of potential storage in the existing

sewage treatment plant units. If the treatment plant

has aerobic or anaerobic digestion tanks, it is often

possible to obtain several weeks storage capacity

by separating the digester(s) to increase solids

content and sewage sludge storage. In addition, older

POTWs often have phased-out tanks, sewage sludge

drying beds, and other areas that are idle and

could be used for sewage sludge storage if properly

modified.

• If possible, locate long-term sewage sludge storage

facilities at the POTW site to take advantage of the

proximity of operating personnel, ease of vandalism

control, and the possibility of sewage sludge volume

reduction, which will reduce transportation costs.

• Minimize the number of times the sewage sludge

must be handled (e.g., transferred, stored) because

costs are incurred each time handling occurs.

14.3.4 Storage Design

Storage capacity can be provided by:

• Stockpiles

• Lagoons

• Tanks, open top or enclosed

• Digesters

It is important to remember that if sewage sludge remains on land (e.g., in stockpiles or lagoons) for longer

than 2 years, the surface disposal requirements in the

Part 503 rule must be met. Chapter 15 of the EPA

Process Design Manual for Sludge Treatment and Disposal (U.S. EPA, 1979) contains a comprehensive discussion of sewage sludge storage design options and

applicable detention times for each type of storage

structure (see Table 15-1 in that manual) and should be

consulted for more details. The different types of storage

systems are summarized below.

Figure 14-5. Example of mass flow diagram using cumulative generation and cumulative sludge application to estimate storage

requirement.

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14.3.4.1 Stockpiles

Stockpiling involves the temporary storage of sewage

sludge that has been stabilized and dewatered or dried

to a concentration (about 20 to 60 percent solids) suitable for mounding with bulldozers or loaders. The sewage sludge is mounded into stockpiles 2 to 5 m (6 to 15

ft) high, depending on the quantity of sewage sludge and

the available land area. Periodic turning of the sewage

sludge helps to promote drying and maintain aerobic

conditions. The process is most applicable in arid and

semiarid regions, unless the stockpiles are covered to

protect against rain. Enclosure of stockpiles may be

necessary to control runoff.

14.3.4.2 Lagoons

Lagoons are often the least expensive way to store

sewage sludge. With proper design, lagoon detention

also provides additional stabilization of the sewage

sludge and reduces pathogens.

14.3.4.3 Tanks

Various types of tanks can be used to store sewage

sludge. In most cases, tanks are an integral part of

sewage sludge treatment processes at a POTW, and the

design for these processes usually includes storage

capabilities. A mobile storage tank (nurse tank) in the

field can serve as a buffer between the transportation

and application of sewage sludge, allowing the operators to work somewhat independently of one another.

The Madison, Wisconsin, program uses such a system

and as a result has observed a 25 percent increase in

its productivity (Jacobs et al., 1993). Liquid sewage

sludge is transported at the Madison site using 5,500-

gallon vacuum trucks that discharge the sewage sludge

into a 12,000-gallon mobile storage tank located at the

application site. A 3,500-gallon application vehicle withdraws sewage sludge from the storage tank and injects

the sludge 6 to 8 inches beneath the soil surface. Two

truckloads normally fill one storage tank and application

vehicle (Jacobs et al., 1993).

14.3.4.4 Treatment Plant Digester Capacity

Many sewage treatment plants do not have separate

sewage sludge retention capacity, but rely on portions

of the digester volume for storage. When available, an

unheated sewage sludge digester may provide shortterm storage capacity. In anticipation of periods when

sewage sludge cannot be applied to the land, digester

supernatant withdrawals can be accelerated to provide

storage of sewage sludge for several weeks.

14.4 Land Application Methods

14.4.1 Overview

The technique used to apply sewage sludge to the land

can be influenced by the means used to transport the

sludge from the treatment works to the land application

site. Commonly used methods include:

• The same transport vehicle hauls the sewage sludge

from the treatment works to the application site and

applies the sewage sludge to land.

• One type of transport vehicle, usually with a large

volume capacity, hauls sewage sludge from the treatment works to the application site. At the application

site, the haul vehicle transfers the sewage sludge

either to an application vehicle, into a storage facility,

or both.

• Sewage sludge is pumped and transported by pipeline from the treatment works to a storage facility at

the application site. Sewage sludge is subsequently

transferred from the storage facility to an application

vehicle.

Sewage sludge land application methods involve either

surface or subsurface application. Each has advantages

and disadvantages that are discussed in the following

subsections. With all of the application techniques, the

sewage sludge eventually become incorporated into the

soil, either immediately by mechanical means or over

time by natural means.

Sewage sludge is applied either in liquid or dewatered

form. The methods and equipment used are different for

land application of these two types of sewage sludge,

and each has advantages and disadvantages that are

highlighted below.

Regardless of the type of application system chosen at

a land application site, attention must be paid to potential physical problems of the soil at the site. One study

of sewage sludge land application programs determined

that farmers who participate in such programs are very

concerned about soil compaction (Jacobs et al., 1993).

Programs in Wisconsin, Colorado, and Michigan using

private farmland have found that attention to potential

soil compaction as well as deep tilling the staging areas

when land application is completed is important. Longterm working relationships with farmers have been enhanced in these programs by managing equipment and

field applications to avoid soil compaction (Jacobs et al.,

1993).

14.4.2 Application of Liquid Sewage Sludge

Application of sewage sludge to land in liquid form is

relatively simple. Dewatering processes are not required, and the liquid sewage sludge can be readily

171
pumped. Liquid sewage sludge application systems include:

• Vehicular surface application by:

– Tank truck spreading, or

– Tank wagon spreading

• Subsurface application by:

– Subsurface injection, or

– Plow furrow or disking methods

• Irrigation application by:

– Spray application, or

– Flood irrigation (gravity flooding)

14.4.2.1 Surface Application

Surface application of liquid sewage sludge involves

spreading without subsequent incorporation into the

soil. Surface application of sewage sludge has been

shown to reduce nutrient and soil loss on no-till cropland

that would otherwise occur through surface water runoff

using other application methods. Surface application

may also have similar benefits on conventionally tilled

cropland (Elliott et al., 1990).

Vehicle Types Available

Table 14-5 describes the methods, characteristics, and

limitations of applying liquid sewage sludge by surface

application. Liquid sewage sludge can be spread on the

soil surface using application vehicles equipped with

splash plates, spray bars, or nozzles. Uniform application is the most important criterion in selecting which of

the three attachments are best suited to an individual

site. Figure 14-6 depicts a tank truck equipped with

splash plates. Figure 14-7 depicts a tank truck with a

rear-mounted “T” pipe. For these two methods, application

rates can be controlled either by valving the manifold or

by varying the speed of the truck. A much heavier application will be made from a full truck than from a nearly

empty truck or wagon unless the speed of the truck or

wagon advancing across the field is steadily decreased

to compensate for the steadily decreasing hydraulic

head (U.S. EPA, 1977). Figure 14-8 depicts a spray

nozzle mounted on a tank truck. By spraying the liquid

sewage sludge under pressure, a more uniform coverage is obtained.

Hauling a full tank of sludge across the application site

compacts the soil (Elliott et al., 1990). Conveyance of

Table 14-5. Surface Application Methods for Liquid Sewage

Sludge (Cunningham and Northouse, 1981)

Method Characteristics

Topographical and

Seasonal

Limitations

Tank truck Capacity 500 to more than

2,000 gallons; flotation tires

desirable; can be used with

temporary irrigation set-up;

can achieve a uniform

application rate with pump

discharge.

Tillable land; not

usable at all times

with row crops or

on very wet ground.

Farm tank

wagon

Capacity 500 to 3,000

gallons; wagon flotation tires

desirable; can be used with

temporary irrigation set-up;

can achieve a uniform

application rate with pump

discharge.

Tillable land; not

usable at all times

with row crops or

on very wet ground.

Metric conversion factor: 1 gal = 3.78 L

Figure 14-7. Slotted T-bar on back of tanker truck (U.S. EPA,

1978).

Figure 14-6. Splash plates on back of tanker truck (U.S. EPA,

1978).

Figure 14-8. Tank truck with side spray nozzle for liquid sludge

surface application (U.S. EPA, 1978).

172
the tank can be eliminated by using a travelling spray

gun connected directly to the sludge delivery vehicle.

Distribution and drift problems can be reduced by using

a “traveling beam” with multiple sprinklers (Elliott et al.,

1990).

14.4.2.2 Subsurface Application

Subsurface application of liquid sewage sludge involves

either subsurface injection or subsurface incorporation

using plow furrow or disking methods. One study found

that the majority of 10 land application programs analyzed use subsurface injection or surface spreading followed by incorporation because these procedures have

proven to be the most effective means of reducing odors

and improving public acceptability of the program (Jacobs et al., 1993). Therefore, the study recommended

the incorporation of sewage sludge into the soil at land

application sites as soon as possible.

Subsurface injection or soil incorporation of liquid sewage sludge has a number of advantages over surface

application, including:

• Potential health and nuisance problems generally can

be avoided. The vector attraction reduction requirements of Part 503 can be met using these subsurface

methods of land application when sewage sludge or

domestic septage is applied to certain types of land

(see Chapter 3).

• Nitrogen is conserved because ammonia volatilization is minimized.

• Public acceptance may be better.

Injection of sewage sludge beneath the soil places a

barrier of earth between the sewage sludge and vectors

such as flies or rodents that could transmit disease (U.S.

EPA, 1992). In addition, when sewage sludge is injected, the soil quickly removes water from the sewage

sludge, which reduces its mobility and odor (U.S. EPA,

1992). As a result, the requirements for vector attraction

reduction in the Part 503 rule can be demonstrated for

certain types of land by injecting the sewage sludge

below the ground. Under this option, no significant

amount of the sewage sludge can be present on the land

surface within 1 hour after injection, and, if the sewage

sludge is Class A with respect to pathogens, it must be

injected within 8 hours after discharge from the pathogen-reduction process (see Chapter 3).

The requirements for vector attraction reduction under

the Part 503 rule also can be demonstrated for certain

types of land by incorporating sewage sludge applied to

the land within 6 hours after application (see Chapter 3).

If the sewage sludge is Class A with respect to pathogens, the time between processing and application must

not exceed 8 hours. After application, the sewage sludge

has to be incorporated into the soil within 6 hours. When

applied at agronomic rates, the loading of sewage

sludge solids typically is about 1/200th of the mass of

soil in the plow layer. If mixing is reasonably good, the

dilution of sewage sludge in the soil surface from incorporation is equivalent to that achieved with soil injection

(U.S. EPA, 1992).

The 6 hours allowed in the regulation to complete the

incorporation of sewage sludge into the soil should be

adequate to allow for proper incorporation. As a practical

matter, it may be wise to complete the incorporation in

a much shorter time. Clay soils tend to become unmanageably slippery and muddy if the liquid sewage sludge

is allowed to soak into the first inch or two of topsoil

(U.S. EPA, 1992).

Some state requirements for the incorporation of sewage sludge once it is land applied may be more stringent

than federal requirements. For example, Kentucky requires incorporation of sewage sludge within 2 hours of

application for odor control (U.S. EPA, 1990).

Subsurface injection or soil incorporation of liquid sewage sludge also has potential disadvantages, however,

compared to surface application of liquid sewage

sludge, including:

• Potential difficulty in achieving even distribution of the

sewage sludge.

• Higher fuel consumption costs.

Vehicle Types Available

Table 14-6 describes the methods, characteristics, and

limitations of applying liquid sewage sludge by subsurface application. Figures 14-9 and 14-10 illustrate equipment specifically designed for subsurface injection of

sewage sludge, which involves tank trucks with special

injection equipment attached. Tanks for the trucks are

generally available with 6,000, 7,500, and 11,000 L

(1,600, 2,000, and 3,000 gal) capacities. Figure 14-11

shows another type of unit, a tractor with a rear-mounted

injector unit; sewage sludge is pumped from a storage

facility to the injector unit through a flexible hose attached to the tractor. Discharge flow capacities of 570

to 3,800 L/min (150 to 1,000 gal/min) are used. The

tractor requires a power rating of 40 to 60 hp.

It is not usually necessary to inject liquid sewage sludge

into the soil when the sludge is applied to existing pasture

or hay fields; however, injection systems are available that

can apply liquid sewage sludge to these areas with a

minimum of crop and soil disturbance (see Figure 14-10).

Soil compaction problems still exist when using injectors. The use of a heavy tank in the field can be avoided

by attaching injectors directly to a tractor tool bar. Sludge

can then be pumped to the injectors from a storage area

or nurse truck using an umbilical hose (Elliott et al.,

1990).

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An example of a land application program using injection is the Madison, Wisconsin, program. The sewage

sludge injection vehicles used in this program have

been modified by increasing the number of injection

shanks to 6 per vehicle and by adding a drag behind the

injectors to smooth the disturbed soil (Jacobs et al.,

1993). Another example is an Arizona program in which

sewage sludge is land applied with a tractor-mounted

injector. The injectors are supplied with sludge through

a hose connected to the pipe system. A second tractor

pulls the hose out of the way as the injecting tractor

traverses the application fields. Sewage sludge is injected in a triple crosshatch pattern for uniform distribution (Jacobs et al., 1993).

The plow or disk and cover method involves discharging

the sewage sludge into a narrow furrow from a wagon

or flexible hose linked to a storage facility through a

manifold mounted on the plow or disk; the plow or disk

then immediately covers the sewage sludge with soil.

Figure 14-12 depicts a typical tank wagon with an attached plow. These systems seem to be best suited for

high loading rates, i.e., a minimum of 3.5 to 4.5 t/ha (8

to 10 dry T/ac) of 5 percent slurry.

Table 14-6. Subsurface Application Methods for Liquid Sewage Sludge (Keeney et al., 1975)

Method Characteristics

Topographic and

Seasonal Limitations

Flexible irrigation hose

with plow or disk cover

Use with pipeline or tank truck with pressure discharge; hose connected

to manifold on plow or disc.

Tillable land; not usable on

very wet or frozen ground.

Tank truck with plow or

disk cover

500-gallon commercial equipment available; sludge discharged in furrow

ahead of plow or disk mounted on rear on four-wheel-drive truck.

Tillable land; not usable on

very wet or frozen ground.

Farm tank wagon with

plow or disk cover

Sludge discharged into furrow ahead of plow mounted on tank trailer;

application of 170 to 225 wet Tons/acre; or sludge spread in narrow

band on ground surface and immediately plowed under; application of

50 to 120 wet Tons/acre.

Tillable land; not usable on

very wet or frozen ground.

Subsurface injection Sludge discharged into channel opened by a chisel tool mounted on

tank truck or tool bar; application rate 25 to 50 wet Tons/acre; vehicles

should not traverse injected area for several days.

Tillable land; not usable on

very wet or frozen ground.

Metric conversion factors: 1 gal = 3.78 L, 1 Ton/acre = 2.24 metric tons/hectare

Figure 14-10. Tank truck with liquid sludge grassland injectors

(courtesy of Rickel Manufacturing Company).

Figure 14-9. Tank truck with liquid sludge tillage injectors

(courtesy of Rickel Manufacturing Company).

Figure 14-11. Tractor-pulled liquid sludge subsurface injection

unit connected to delivery hose (courtesy of Briscoe Maphis Company).

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14.4.2.3 Irrigation Application

Irrigation application of liquid sewage sludge has been

accomplished using spray irrigation and flood irrigation.

Spray irrigation has been used primarily for forest land

applications; its usefulness for agricultural applications

may be limited by cropping schedules and public acceptance (see Chapter 7). Flood irrigation of sewage sludge

generally has not been successful and is usually discouraged by regulatory agencies.

Spray Irrigation

Spray irrigation has been used to disperse liquid sewage sludge on clearcut openings and in forest stands.

Liquid sewage sludge is readily dispersed through spray

systems if properly designed equipment is used. Solids

must be relatively small and uniformly distributed throughout the sewage sludge to achieve uniform application and

to avoid system clogging. A typical spray application

system consists of the use of a rotary sprayer (rain gun)

to disperse the liquid sewage sludge over the application site. The sludge, pressurized by a pump, is transferred from storage to the sprayer via a pipe system.

Design of the system can be portable or permanent and

either mobile or stationary. Available spray irrigation

systems include (Loehr et al., 1979):

• Solid set, both buried and above ground

• Center pivot

• Side roll

• Continuous travel

• Towline laterals

• Stationary gun

• Traveling gun

The utility of these systems within the application site

depends on the application schedule and management

scheme utilized. All the systems listed, except for the

buried solid system, are designed to be portable. Main

lines for systems are usually permanently buried,

providing protection from freezing weather and heavy

vehicles.

The proper design of sewage sludge spray application

systems requires thorough knowledge of the commercial equipment available and its adaptation for use with

liquid sewage sludge. It is beyond the scope of this

manual to present engineering design data for these

systems, and it is suggested that qualified irrigation

engineers and experienced irrigation system manufacturers be consulted.

Figures 14-13, 14-14, and 14-15 illustrate some of the

spray systems listed above.

Flood Irrigation

In general, land application of sewage sludge by flood

irrigation, also known as gravity flooding, has not been

successful where attempted and is discouraged by

regulatory agencies and experienced designers. Problems arise from (1) difficulty in achieving uniform sewage sludge application rates; (2) clogging of soil pores;

and (3) tendency of the sewage sludge to turn septic,

resulting in odors.

14.4.3 Application of Dewatered Sewage

Sludge

Dewatered sewage sludge is applied to land by surface

application techniques. The principal advantages of using dewatered sewage sludge are:

• Reduced sewage sludge hauling and storage costs.

Figure 14-12a. Tank wagon with sweep shovel injectors (Cunningham and Northouse, 1981).

Figure 14-12b. Sweep shovel injectors with covering spoons

mounted on tank wagon (Cunningham and Northouse, 1981).

175
• The ability to apply sewage sludge at higher application rates with one pass of the equipment.

Potential disadvantages of applying dewatered sewage

sludge are:

• Generally, substantial modification of conventional spreading equipment is necessary to apply dewatered sludge.

• More operation and maintenance is generally incurred in equipment repairs compared to many liquid

sewage sludge application systems.

Table 14-7 describes methods and equipment for applying dewatered sewage sludge to the land.

14.4.3.1 Vehicle Types Available

Spreading of dewatered sewage sludge is similar to

surface application of solid or semisolid fertilizers, lime,

or animal manure. Dewatered sewage sludge cannot be

pumped or sprayed. Spreading is done by box spreaders, bulldozers, loaders, or graders, and the sludge is

then plowed or disked into the soil. The box spreader is

most commonly used, with the other three equipment

items generally being used only for sites with high sewage sludge application rates.

Figures 14-16 and 14-17 illustrate the specially designed trucks used to spread dewatered sewage sludge.

For small quantities of dewatered sludge, conventional

tractor-drawn farm manure spreaders may be adequate

(Loehr et al., 1979). Surface spreading of dewatered

sludge on tilled land usually is followed by incorporation

of the sludge into the soil. It is not usually necessary to

incorporate dewatered sludge into the soil when the

sludge is applied to existing pasture or hay fields. Standard agricultural disks or other tillage equipment pulled

by a tractor or bull dozer can incorporate the dewatered

sludge into the soil, such as the disk tiller, disk plow, and

disk harrow (Figures 14-18 and 14-19).

In Denver, Colorado, spreaders were custom-built to

provide a more even application of dewatered sewage

Figure 14-14. Traveling gun sludge sprayer (courtesy of Lindsay Manufacturing Company).

Figure 14-13. Center pivot spray application system (courtesy

of Valmont Industries Inc.).

Figure 14-15. Diagram of liquid sludge spreading system in forest land utilizing temporary storage ponds (Water Pollution Control

Federation, 1981).

Table 14-7. Methods and Equipment for Application of

Dewatered Semisolid and Solid Sludges

Method Characteristics

Spreading Truck-mounted or tractor-powered box spreader

(commercially available); sludge spread evenly on

ground; application rate controlled by PTD and/or

over-the-ground speed; can be incorporated by

disking or plowing.

Piles Normally hauled by dump truck; spreading and

leveling by bulldozer or grader needed to give

uniform application.

176
sludge than commercially available spreaders (Jacobs

et al., 1993). The district’s spreaders have a metering

screw and gauge that allow the operator to achieve

relatively even applications. In addition, the district installed a heating system on the spreader box, which

allowed the sewage sludge to be spread during the

winter months. Following surface application, the sewage sludge at the Denver site is incorporated into the

soil by disking or plowing (Jacobs et al., 1993).

In Sparks, Nevada, dewatered sewage sludge is unloaded at the application site into a windrow at the edge

of the spreading area. The sludge unloading area

changes as the spreading area changes, thus avoiding

the development of “hot spots” with extremely high sewage sludge loadings (Jacobs et al., 1993). From the

windrow, a front-end loader places the sludge into a

side-slinger manure spreader, which spreads the sludge

onto the field. The same person operates the front-end

loader and the spreader. Fields are spread in sections,

with the length of a section determined by the distance

required to empty a spreader; a spreader swath usually

is approximately 80 feet wide by 200 feet long. The

tractor to which the spreader is attached is equipped

with hydraulic drive to facilitate speed changes. The

side-slinger design enables the tractor and spreader to

travel on ground that has not yet received sludge application, thus keeping the equipment clean. At the end of

each day, the field is disked twice to completely cover

the sewage sludge with soil (Jacobs et al., 1993).

14.5 Site Preparation

14.5.1 General

For agricultural land application systems where sewage

sludge is applied to privately owned farms at low agronomic application rates, site modifications are not typically cost-effective. At forested systems, usually there is

much more forest land available within the local area

than is needed for sewage sludge land application, so

unsuitable land can be avoided rather than modified. In

the case of land application of sewage sludge at reclamation sites, extensive site grading and soil preparation

often are necessary. These site preparation costs, however, are usually borne by the land owner (e.g., mining

company, ore processor, etc.) and not by the municipality (see Chapter 9 for a discussion of land application of

sewage sludge at reclamation sites).

14.5.2 Protection of Ground Water and

Surface Water Quality

One of the major environmental tasks at a sewage

sludge land application site is the prevention of surface

and subsurface water contamination by constituents in sewage sludge. Nitrogen and phosphorus in surface waters and

nitrate in ground water are usually the constituents of most

Figure 14-18. Example of a disk tiller.

Figure 14-19. Example of a disk plow.

Figure 14-17. Large dewatered sludge spreader (courtesy of BJ

Manufacturing Company).

Figure 14-16. A 7.2-cubic-yard dewatered sludge spreader

(courtesy of Big Wheels Inc.).

177
concern. The Part 503 pollutant limits and agronomic

rate requirement address these water quality concerns.

Good management practices, such as incorporating or

injecting sewage sludge, minimize the amount of sludge

that can come into contact with rain, thus reducing

potential water contamination (Lue-Hing et al., 1992). If

runoff might occur from a land application site, the water

quality of the runoff should be within acceptable limits,

or the water can be detained in a holding structure and

reapplied to land or treated (Lue-Hing et al., 1992).

Ways to reduce potential water contamination include

grading and erosion control, as discussed below.

14.5.3 Grading

The purpose of establishing surface grades is to ensure

that runoff water and/or liquid sewage sludge do not

pond. Design plans should emphasize that depressions

can be filled with soil from adjoining ridges and mounds.

If an excessive amount of filling is required for low areas,

or if sufficient soil is not readily available, field ditches

can be installed and the surfaces warped towards them.

In areas with little or no slope, grades can be established

or increased by grading between parallel ditches with

cuts from the edge of one ditch and fills from the next.

Terraces may be needed to protect lower lands from

surface water runoff that can cause soil erosion. Terraces generally are dug across a slope or at the toe of

a slope, with the borrow material diked on the lower side

for efficiency. Diversion terraces generally are graded

and grass-covered so that the collected water may be

delivered at non-erosive flows to a controlled discharge

point.

A number of states have requirements for the maximum

grade allowable at land application sites and for runoff

control (U.S. EPA, 1990). Requirements for runoff control range from forbidding application on saturated

ground, as in Mississippi, to specifying designs for runoff

control systems (e.g., capacity for a 10-year, 1-hour

storm), as in Texas.

14.5.4 Erosion Control

The measures used to prevent soil erosion include strip

cropping, terraces, grassed waterways, and reduced

tillage systems (e.g., chisel plowing, no-till planting).

Strip cropping involves planting alternating strips (e.g.,

hay and corn) so that when one crop is harvested, soil

erosion from the harvested strips is contained by the

strips that remain vegetated. The strips are alternated

periodically. The presence of vegetation and/or crop

residues on the soil surface is effective in reducing

runoff from steeply sloping soils. For many cropping

systems (e.g., corn, soybeans, small grains), liquid

sludge applied to the surface is incorporated into the soil

by plowing or disking prior to crop planting, further reducing the potential for loss of sludge constituents via

surface runoff. In essence, selection of the proper sludge

application method (surface or incorporation) in conjunction with currently recommended practices for control of soil erosion will essentially eliminate the potential

contamination of surface waters or adjacent lands by

sewage sludge constituents.

Every land application site should be designed to minimize soil erosion. The MWRD in Denver, Colorado, for

example, performs soil management practices recommended by the Department of Agriculture Natural Resources Conservation Service (NRCS) and the Consolidated

Farm Service Agency (formerly Agriculture Stabilization

and Conservation Service) to help reduce the potential for

soil erosion. Information on proper slopes, effective conservation tillage, and wind erosion techniques for agricultural lands can be obtained from the NRCS.

14.6 Design of Supporting Facilities

The cost of supporting facilities, such as permanent

all-weather access roads and fences, can usually be

justified only for sites with high sewage sludge application rates that will be used over a long project life. These

conditions rarely apply to privately owned agricultural

land application sites.

14.6.1 Access Roads

A permanent road should be provided from the public

road system to the land application site. For large sites,

the roadway should be 6.5 to 8 m (20 to 24 ft) wide to

allow for two-way traffic; for smaller sites, a 5 m (15 ft)

wide road should suffice. To provide all-weather access,

the roadway, at a minimum, should be gravel-surfaced,

preferably with asphalt pavement. Grades should not

exceed equipment limitations. For loaded vehicles, uphill grades should be less than 7 percent.

14.6.2 Public Access: Site Fencing and

Security

Under the Part 503 rule, public access restrictions apply

to land application sites where sewage sludge meeting

Class B pathogen requirements is applied (see Chapter

3). Access to lands with a high potential for public exposure, such as parks or ballfields, must be restricted for

1 year after sewage sludge application. Examples of

restricted access include remoteness, posting with “no

trespassing” signs, and/or fencing. Access to land with

a low potential for public exposure (e.g., private farmland) must be restricted for 30 days after sewage sludge

application.

Depending on the topography and vegetation of the site

and adjoining areas, entrance gates may suffice to prevent unauthorized vehicular access. At some sites, it will

be necessary to construct peripheral fences to restrict trespassers and animals. Fencing requirements are influenced

178
by the relative isolation of the site. Sites close to residences will require fencing. Facilities that are in relatively isolated, rural areas may require a less

sophisticated type of fence or only fencing at the entrance and other select places to keep unauthorized

vehicles out.

14.6.3 Equipment and Personnel Buildings

Application equipment and staging areas should be

managed at land application facilities in ways that avoid

compaction of soils receiving sewage sludge (Jacobs et

al., 1993). Avoidance of potential compaction problems

will enhance the long-term working relationship between

a treatment works and crop producers.

At larger facilities, or where climates are extreme, buildings may be necessary for office space, equipment, and

employees. Where land application sites are operated

throughout the year, some protection from the elements

for employees and equipment may be necessary. Sanitary facilities should be provided for both site and hauling personnel. At smaller facilities where buildings

cannot be justified, trailers may be warranted.

14.6.4 Lighting and Other Utilities

If land application operations occur at night, portable

lighting should be provided at the operating area. Lights

may be affixed to haul vehicles and on-site equipment.

These lights should be situated to provide illumination

to areas not covered by the regular headlights of the

vehicle. If the facility has structures (e.g., employee

facilities, office buildings, equipment repair or storage

sheds) or if the access road is in continuous use, permanent security lighting may be needed.

Larger sites may need electrical, water, communication,

and sanitary services. Remote sites may have to extend

existing services or use acceptable substitutes. Portable

chemical toilets can be used to avoid the high cost of

extending sewer lines; potable water may be trucked in;

and an electrical generator may be used instead of

having power lines run on-site.

Water should be available for drinking, dust control,

washing mud from haul vehicles before entering public

roads, and employee sanitary facilities. Telephone or

radio communications may be necessary since accidents or spills can occur that necessitate the ability to

respond to calls for assistance.

14.7 References

Cunningham, J., and M. Northouse. 1981. Land application of liquid

digested sewage sludge (METROGRO) at Madison, Wisconsin.

In: Seminar proceedings, land application of sewage sludge. Virginia Water Pollution Control Association, Inc., Richmond, VA.

pp. 111-145.

Elliott, H., B. Dempsey, D. Hamilton, and J. Wolfe. 1990. Land application of water treatment plant sludges: Impact and management.

American Water Works Research Foundation, Denver, CO.

Ettlich, W. 1976. What’s best for sludge transport? Water Wastes

Engin. 13(10):20-23.

Haug, R., L. Tortorici, and S. Raksit. 1977. Sludge processing and

disposal. LA/OMA Project, Whittier, CA.

Jacobs, L., S. Carr, S. Bohm, and J. Stakenberg. 1993. Document

long-term experience of sewage sludge land application programs. Water Environment Research Foundation, Alexandria, VA.

Keeney, D., K. Lee, and L. Walsh. 1975. Guidelines for the application

of wastewater sludge to agricultural land in Wisconsin. Technical

Bulletin No. 88, Wisconsin Department of Natural Resources,

Madison, WI.

Loehr, R., W. Jewell, J. Novak, W. Clarkson, and G. Friedman. 1979.

Land application of wastes, Vol. 2. New York, NY: Van Nostrand

Reinhold.

Lue-Hing, C., D. Zenz, and R. Kuchenrither. 1992. Municipal sewage

sludge management: Processing, utilization, and disposal. In:

Water quality management library, Vol. 4. Lancaster, PA: Technomic Publishing Co.

Taylor, D. June 1994. Revision, projected monthly sludge distribution

for agricultural sludge utilization program, Madison, WI.

U.S. EPA. 1992. Control of pathogens and vector attraction in sewage

sludge. EPA/625/R-92/013. Washington, DC.

U.S. EPA. 1990. Guidance for writing case-by-case permit requirements for municipal sewage sludge. EPA/505/8-90/001. Washington, DC.

U.S. EPA. 1979. Process design manual for sludge treatment and

disposal. EPA/625/1-79/011. Washington, DC.

U.S. EPA. 1978. Sludge treatment and disposal, Vol. 2. EPA/625/4-

78/012. Cincinnati, OH.

U.S. EPA. 1977a. Cost of land spreading and hauling sludge from

municipal wastewater treatment plants—Case studies. EPA/30/

SW-619. Washington, D.C.

U.S. EPA. 1977b. Transport of sewage sludge. EPA/600/2-77/216.

Washington, DC.

Water Pollution Control Federation. 1981. Design of wastewater and

stormwater pumping stations. In: Manual of practice FD-4. Washington, DC.

179
Chapter 15

Management, Operational Considerations,

and Recordkeeping and Reporting

15.1 Sewage Sludge Management Plans

In accordance with the Clean Water Act of 1987, EPA

must include sludge requirements in NPDES permits to

protect public health and the environment. To determine

appropriate requirements for land application, EPA requests information from the applicant receiving a permit

on current sewage sludge handling and use practices,

and a 5-year sludge operating plan that describes an

applicator’s sludge marketing areas and planning procedures for new sites (U.S. EPA, 1993a). This Sludge

Management Plan must be included with the permit

application. In addition, the Plan acts as a blueprint for

sludge activities (U.S. EPA, 1993a), and fulfills the requirement of 40 CFR Part 501 that both NPDES and

non-NPDES entities prepare a land application plan for

sewage sludge. The major elements of a Sludge Management Plan are summarized in Figure 15-1.

EPA will discuss current practices and new site operating procedures outlined in a Sludge Management Plan

with personnel in state environmental programs and

with the USDA Soil Conservation Service and/or State

Extension Service in counties where sludge might be

marketed as part of the permitting process (U.S. EPA,

1993a). Upon approval of a Sludge Management Plan by

EPA, the plan becomes an enforceable part of the permit.

In addition to sludge management plans, all land application operation managers should prepare an operation

program, with responsibility clearly defined for its implementation. Essential elements of the operation program

include:

• Flexible scheduling of sludge transport, storage, and

application activities to accommodate a treatment

works need to remove sludge, as well as design

needs for land application of the sludge to the site(s).

• Design, management, operation, and maintenance of

the sludge transport system to minimize potential nuisance and health problems. The system should include a procedure for rapid response to accidents,

spills, and other emergency conditions that may arise

during routine sludge transport operations.

• Design, management, operation, and maintenance of

the sludge application site(s) and equipment to minimize potential nuisance and health problems. Where

privately owned and operated land is involved (e.g.,

farms, commercial forest land, mined lands), the

owner/operator is a key participant in the overall application site management and operation program.

• Recordkeeping, including adequate documentation of

program activities. See Section 15.6 for a discussion

on recordkeeping at land application sites.

• Health and safety, including necessary, routine procedures for protecting the general public and operations personnel.

15.2 Part 503 Requirements Affecting

Land Application Site Operation

Under the Part 503 regulation, Class B site restrictions

must be met at land application sites where sewage

sludge meeting Class B pathogen requirements is applied (U.S. EPA, 1994a). The Class B site restrictions in

Part 503 include restrictions for harvesting crops and

turf, grazing animals, and limiting public access to these

sites. Figure 15-2 describes these restrictions, while

Figure 15-3 includes examples of crops impacted by the

Class B site restrictions. Also, see Chapter 3 for required

Part 503 management practices.

15.3 Nuisance Issues

Minimizing adverse aesthetic impacts of a sewage

sludge land application system will aid in maintaining

public acceptance of the project. Conscientious housekeeping can help make the difference between public

perception of the operation as a professional endeavor

and public disapproval of the project. The following features reflect good housekeeping (Elliott et al., 1990):

• Well maintained, clean vehicles.

• Application and storage areas that are well kept,

clean, and fenced, if necessary.

• Satisfied land owners.

• Well kept records.

181
As part of the NPDES permit application, submit to EPA a Sludge

Management Plan (Plan). The Plan includes current sludge

practices and a 5-year sludge operating plan as listed below.

A. A description of the permittee’s sludge production and any current and known future land application sites.

B. A list of the counties (and states if applicable) where the permittee may want to market or distribute its sludge over the life of

the permit (5 years minimum). A copy of the plan must be submitted to the respective State Health Department, and should

be submitted to the State Extension Service Office in the counties where sludge may be marketed.

C. Site selection criteria to be used when identifying new land application sites.

D. Site management practices being followed relating to, at a minimum: floodplain, slope, depth to ground water, weather conditions, soil conditions (compaction, permeability, saturated,

frozen, snow-covered), site access, and protection of surface

waters, wetlands, endangered species, and underground drinking water sources at current sites; and operating procedures

(e.g., qualified soils consultant, Soil Conservation Service,

State Extension Service) for annual adjustments and for setting site management practices for future sites.

E. Buffer zones between sludge application sites and: surface waters, drinking water wells, drainage ditches, property lines, residences, schools, playgrounds, airports, public roadways, and

any necessary site-specific buffer zones for current sites; and

operating procedures (e.g., qualified soils consultant, Soil Conservation Service, State Extension Service) for making annual

adjustments and for setting buffer zones for future sites.

F. Storage provision for sludge during periods when sludge cannot be land applied.

G. Either Part 503 pollutant concentration limits, or maximum acceptable total cumulative application rates, expressed as kilograms per hectare (kg/ha) (or annual application rates for

bagged sewage sludge, kg/ha/yr), for arsenic, cadmium, chromium, copper, lead, mercury, molybdenum nickel, selenium, and

zinc, and any other pollutants regulated by the Part 503 rule.

H. Maximum acceptable sludge application rate to assure that the

amount of sludge applied does not exceed the nutrient requirements of the particular crop grown on the application site (agronomic rates) for current year crops, and operating procedures

(e.g., by qualified soils consultant, Soil Conservation Service,

State Extension Service) for making annual agronomic rate adjustments and for setting agronomic rates for future sites.

I. A description of the pathogen treatment, vector attraction control, record keeping, monitoring, certifications, and notifications

as required by the 40 CFR Part 503 regulation.

J. Reference to applicable regulations (40 CFR Part 503) and

procedures the permittee intends to use to ensure that the

sludge practices and limits outlined are followed.

K. Information described in 40 CFR 501.15(2) (states may require

additional information).

L. Public notice procedures and procedures for advanced notice to

EPA (at least 60 days) of proposed new land application sites.

M. Procedures, or copies of documents specifying procedures

(e.g., contracts) that will be used to ensure compliance with

this permit and applicable regulations if the permittee contracts

with others for assistance to select and/or manage the land application sites itself.

N. Contingency plans that describe sludge disposal options for

any sludge which does not meet the requirements for land application or exceeds storage capacity.

O. A statement (e.g., city ordinance) that the permittee will comply

with the Sludge Management Plan, as approved by EPA.

P. A statement that the Plan will be amended to reflect any applicable practices or limits EPA promulgates pursuant to Section

405 of the Act.

Figure 15-1. Sludge Management Plan (U.S. EPA, 1993a).

Restrictions for the harvesting of crops* and turf:

1. Food crops, feed crops, and fiber crops shall not be harvested

until 30 days after sewage sludge application.

2. Food crops with harvested parts that touch the sewage

sludge/soil mixture and are totally above ground shall not be

harvested until 14 months after application of sewage sludge.

3. Food crops with harvested parts below the land surface where

sewage sludge remains on the land surface for 4 months or

longer prior to incorporation into the soil shall not be harvested

until 20 months after sewage sludge application.

4. Food crops with harvested parts below the land surface where

sewage sludge remains on the land surface for less than 4

months prior to incorporation shall not be harvested until 38

months after sewage sludge application.

5. Turf grown on land where sewage sludge is applied shall not

be harvested until 1 year after application of the sewage

sludge when the harvested turf is placed on either land with a

high potential for public exposure or a lawn, unless otherwise

specified by the permitting authority.

Restriction for the grazing of animals:

1. Animals shall not be grazed on land until 30 days after application of sewage sludge to the land.

Restrictions for public contact:

1. Access to land with a high potential for public exposure, such

as a park or ballfield, is restricted for 1 year after sewage

sludge application. Examples of restricted access include posting with no trespassing signs, and fencing.

2. Access to land with a low potential for public exposure (e.g.,

private farmland) is restricted for 30 days after sewage sludge

application. An example of restricted access is remoteness.

*Examples of crops impacted by Class B pathogen requirements are

listed in Figure 15-3.

Figure 15-2. Restrictions for the harvesting of crops and

turf, grazing of animals, and public access on

sites where Class B biosolids are applied.

Harvested Parts That:

Usually Do Not Touch

the Soil/Sewage 

Sludge Mixture

Usually Touch the

Soil/Surface

Are Below the

Soil/Surface

Peaches Melons Potatoes

Apples Strawberries Yams

Oranges Eggplant Sweet Potatoes

Grapefruit Squash Rutabaga

Corn Tomatoes Peanuts

Wheat Cucumbers Onions

Oats Celery Leeks

Barley Cabbage Radishes

Cotton Lettuce Turnips 

Soybeans Beets

Figure 15-3. Examples of crops impacted by site restrictions

for Class B sewage sludge (U.S. EPA, 1994a).

182
Continuous efforts should be made to avoid or reduce

nuisance problems associated with sludge hauling, application, and related operations. Potential nuisances of

concern include odor, spillage, mud, dust, noise, road

deterioration, and increased local traffic, as discussed

below.

15.3.1 Odor

All sludge management systems must consider objectionable odor as a potential problem. Objectionable

odors could result in an unfavorable public reaction and

reduced acceptance of land application practices.

It is important to note that when pathogen reduction and

vector attraction reduction is achieved according to requirements specified in the Part 503 rule (see Chapter

3 for a complete discussion of these requirements), odor

should not pose a problem at land application sites. For

example, injection of sewage sludge beneath the soil

(Option 9 for demonstrating reduced vector attraction of

sewage sludge) places a barrier of earth between the

sewage sludge and vectors. The soil quickly removes

water from the sludge, which reduces the mobility and

odor of the sewage sludge. Odor is usually present at

the site during the injection process, but it quickly dissipates when injection is completed (U.S. EPA, 1992).

Potential for odors also can be reduced or eliminated by:

• Incorporation of sludge as soon as possible after

delivery and application to the site.

• Daily cleaning (or more frequently, if needed) of

trucks, tanks, and other equipment.

• Avoiding sludge application to waterlogged soils or

when other soil or slope conditions would cause

ponding or poor drainage of the applied sludge.

• Use of proper sludge application rates for application

site conditions.

• Avoiding or limiting the construction and use of

sludge storage facilities at the land application site,

or designing and locating the sludge storage facilities

in a way that prevents odor problems. Experience

has shown that sludge storage facilities are a major

cause of odor problems at land application sites.

• Isolation of the sludge application site from residential, commercial, and other public access areas.

Prevention of odor problems by using the recommendations listed above is important for public acceptance of

land application programs. If odor problems resulting in

citizen complaints do occur, the project management

should have established procedures for correcting the

problems and responding to complaints.

15.3.2 Spillage

All trucks involved in handling sludge on highways

should be designed to prevent sludge spillage. Liquid

sludge tankers generally do not present a problem. For

sludge slurries (10 to 18 percent solids), specially designed haul vehicles with anti-spill baffles have been

effectively employed. Sludge spillage on-site can generally be best controlled using vacuum transfer systems.

If mechanical or human errors during transport or at the

application site do result in spillage of sludge, cleanup

procedures should be employed as soon as possible.

Major spills may result from traffic accidents, faulty or

poorly maintained equipment, or inadequate storage

facilities (Elliott et al., 1990). Major spills can be minimized by properly training drivers and applicators; locating application sites along well maintained roads;

providing adequate storage for equipment so that it is

not exposed to bad weather conditions; properly designing storage facilities; and regularly maintaining equipment (Elliott et al., 1990).

Small, minor spills should also be avoided. Minor spills

can occur as hoses are uncoupled between a nurse

truck and a tank wagon, when equipment is overfilled,

when the seal on a dumptruck tailgate wears out, and

numerous other situations (Elliott et al., 1990). Minor

spills can be prevented with proper equipment maintenance and careful material handling.

15.3.3 Mud

Tracking of mud from the field onto highways, as well as

field or access road rutting by sludge transport or applicator equipment are nuisance concerns. Mud can be a

particularly severe problem in areas with poor drainage,

but can occur at any site during periods of heavy rain or

spring thaws. Choose all-weather site access roads or

modify access roads with gravel or other acceptable

weight-bearing material. To minimize problems with

mud, the following management steps should be considered:

• Use vehicles with flotation tires.

• Use vehicles with smaller capacity, or temporarily reduce volume of sludge being hauled.

• Remove mud tracked on roads.

• Wash down vehicles regularly when moving between

sites to prevent tracking of mud on highways. This

process also improves the public image of sludge

hauling and handling systems and enhances continued community acceptance.

15.3.4 Dust

Dust movement off-site increases with wind or movements of haul vehicles and equipment. To minimize dust

183
generation, access roads may need to be graveled,

paved, oiled, or watered.

15.3.5 Noise

Noise levels from use of heavy equipment (e.g., tractors,

subsurface injector vehicles) at land application sites

may be a concern in some communities. In agricultural

areas, noise (and dust) should generally be no worse

than expected from normal farming operations and

should not create problems. In more populated areas,

use of buffer zones and vegetative screening (trees and

shrubs around the site) may be needed to mitigate

public impact.

15.3.6 Road Maintenance

The breakup of roads by heavy sludge hauling vehicles

can be a problem, particularly in northern climates, and

can result in public complaints. Project management

should have provisions to repair roads or a fund available to help finance cost of road repairs resulting from

project activity.

15.3.7 Selection of Haul Routes

Routes for sludge haul trucks should avoid residential

areas to prevent nuisance caused by truck and air brake

noise, dangers to children, and complaints regarding

frequency of hauling.

15.4 Safety Concerns

Managers of sewage sludge land application systems

have an obligation to maintain safe and secure working

conditions for all personnel and residents, including individuals working directly with the sludge (e.g., POTW

personnel, sludge haulers, farmers, heavy equipment

operators), as well as persons living or working near an

application site or visiting the site. It is important that

safety rules are written, published, distributed to all employees, and enforced. A safety training program, covering all aspects of site safety and proper equipment

operation, as required by OSHA, should be conducted

on a regular basis.

Safety features should be incorporated into every facet

of the land application system design. Certain practices

should be followed routinely to assure safe working

conditions. The official operations program should contain specific safety guidelines for each operation and

feature of the system.

The operation of sludge hauling and application equipment presents the greatest potential for accidents.

Regular equipment maintenance and operational safety

checks should be conducted.

The stability of the soil can present a potential safety

problem, particularly when operating large equipment.

Vehicles should approach disturbed or regraded sites,

muddy areas, or steep slopes cautiously to prevent

tipping or loss of control.

As with any construction activity, safety methods should

be implemented in accordance with Occupational Safety

and Health Administration (OSHA) guidelines. In accordance with OSHA guidelines, the following precautions and procedures should be employed for sludge

land application projects:

• A safety manual should be available for use by employees, and all employees should be trained in all

safety procedures.

• Appropriate personal safety devices, such as hardhats, gloves, safety glasses, and footwear, should be

provided to employees.

• Appropriate safety devices, such as rollbars, seatbelts, audible reverse warning devices, and fire extinguishers, should be provided on equipment used

to transport, spread, or incorporate sludge.

• Fire extinguishers should be provided for equipment

and buildings.

• Communications equipment should be available onsite for emergency situations.

• Work areas and access roads should be well marked

to avoid on-site vehicle mishaps.

• Adequate traffic control should be provided to promote an orderly traffic pattern to and from the land

application site to maintain efficient operating conditions and avoid traffic jams on local highways.

• Public access to the sludge application site should

be controlled. The extent of the control necessary will

depend on the sludge application practice being

used, the time interval since sludge was last applied,

and other factors (see applicable process design

chapters 7 through 9). In general, public access to

application sites should be controlled during sludge

application operations and for an appropriate time

period after the sludge is applied.

15.4.1 Training

It is important for land application facilities to employ well

trained personnel. Qualified personnel can be the difference between a well organized, efficient operation and

a poor operation. New employees should not only learn

the tasks required for their positions, but also understand the purposes and importance of the overall land

application operation. Equipment should be operated

only by fully trained and qualified operators.

A training program should be conducted for site personnel by the engineer who designed the land application

program or someone well acquainted with the operation.

184
Training programs should incorporate the following (Elliott

et al., 1990):

• All aspects of operation, from sludge production to

growth of crops, should be discussed.

• Equipment operators should fulfill licensing requirements.

• Applicators should be taught to calculate application

rates and calibrate equipment.

• Good housekeeping should be stressed during all

phases of training.

15.5 Health Concerns

15.5.1 General

A discussion of pathogens and vectors that may be

associated with sewage sludge is contained in Chapters

3 and 4. Although bacteria, viruses, and parasites are

generally present in sewage sludge, the requirements in

Subpart D of the Part 503 regulation protect public

health and the environment through requirements designed to reduce the density of organisms in sewage

sludge to below detectable levels, or, through a combination of organism reduction and site restrictions, allow

the environment to further reduce organisms to below

detectable levels (U.S. EPA, 1992).

In addition, research by EPA and others has shown no

significant health problems for personnel who are in

contact with sewage sludge on a regular basis at

POTWs or land application sites (Burge and Marsh,

1978; Clark et al., 1980). Furthermore, epidemiological

studies have shown no significant health problems for

people living or working close to sites receiving land

applied sewage sludge or wastewater (U.S. EPA, 1985;

Kowal, 1983; Pahren et al., 1979).

15.5.2 Personnel Health Safeguards

It is recommended that project management include

health safeguards for personnel involved with sludge

transport and handling, including:

• Provide regular typhoid and tetanus inoculations and

poliovirus and adenovirus vaccinations.

• Limit direct contact with aerosols as much as possible

where liquid sludge application techniques are used.

• Encourage proper personal hygiene.

• Provide annual employee health checkups.

• Record reported employee illnesses; if a pattern

(trend) of illnesses potentially associated with sludge

pathogens develops, investigate and take appropriate

action.

15.6 Recordkeeping and Reporting

15.6.1 General

The Part 503 regulation requires that certain records be

kept by the person who prepares sewage sludge for land

application and the person who applies sewage sludge

to the land. The regulation defines the person who prepares sewage sludge as “either the person who generates sewage sludge during the treatment of domestic

sewage in a treatment works or the person who derives

a material from sewage sludge.” This definition covers

two types of operations—those that generate sewage

sludge and those that take sewage sludge after it has

been generated and change the quality of the sewage

sludge (e.g., blend or mix it with another material) prior

to use or disposal. Any time the sewage sludge quality

(e.g., pollutant concentrations, pathogens levels, or vector attraction characteristics) is changed, the person

responsible for the change is defined as a person who

prepares sewage sludge. Recordkeeping requirements

for preparers and appliers of sewage sludge are summarized in Table 15-1, and specific requirements are

discussed in Sections 15.6.2 and 15.6.3. Dewatering

sewage sludge is not considered to be changing the

quality of the sewage sludge.

Preparers and appliers of sewage sludge should be

aware that failure to keep adequate records is a violation

of the Part 503 regulation and subject to administrative,

civil, and/or criminal penalty under the Clean Water Act.

15.6.2 Part 503 Recordkeeping

Requirements for Preparers of

Sewage Sludge

Part 503 requires the person who prepares sewage

sludge to evaluate sewage sludge quality, maintain records, submit compliance reports (for some preparers),

and distribute sludge quality information to subsequent

preparers and appliers who need the information to

comply with the other requirements of the regulation.

With respect to pollutants, the Part 503 regulation requires the preparer to maintain records documenting the

concentration of regulated pollutants in the sewage

sludge. With respect to pathogens and vector attraction,

the records must describe how the pathogen and vector

attraction reduction requirements were met (if one of the

vector attraction reduction options 1 through 8 was met,

see Chapter 3) and include a signed certification of their

achievement. The regulation specifies that records be

maintained for a period of at least 5 years.

U.S. EPA (1993b) presents a detailed discussion of the

recordkeeping responsibilities for preparers of sewage

sludge under Part 503.

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15.6.2.1 Records of Pollutant Concentrations

The preparer is responsible for documenting the sampling and analysis of pollutant concentrations in sewage

sludge; to demonstrate this, the records outlined in Figure 15-4 should be maintained.

When sewage sludge or material derived from sewage

sludge that is destined for land application does not

meet the pollutant concentration limits in Chapter 3,

Table 3-4, additional records must be kept to demonstrate compliance with either the cumulative pollutant

loading rate limits or the annual pollutant loading rate

limits outlined in Table 3-4, as appropriate.

If the preparer plans to sell or give away the sewage

sludge in a bag or other container for application to the

land, he or she must develop and retain the following

additional records (if the sewage sludge does not meet

“exceptional quality” criteria, as discussed in Chapter 3):

• Calculation of an annual whole sludge application

rate (AWSAR) that will not exceed the annual pollutant loading rate limits in Chapter 3, Table 3-4.

• A copy of the label or information sheet provided to

persons who will land apply the sewage sludge.

15.6.2.2 Certification of Pathogen Reduction

The Part 503 regulation requires the maintenance of

records that include a certification by the preparer that

the pathogen requirements were met and a description

of how compliance was achieved. The general certification statement that must be used is provided in Figure

15-5. Usually, the description should explain the treatment process for pathogen reduction and be supported

Table 15-1. Part 503 Recordkeeping and Reporting Requirements (U.S. EPA, 1994a)

Person Responsible

for Recordkeeping

Type of Sewage

Sludge Records That Must Be Kept Preparer Applier

Records That Must

Be Reporteda

EQ Sewage Sludge Pollutant concentrations

Pathogen reduction certification and description

Vector attraction reduction certification and description

✔

✔

✔

✔ 

✔ 

✔ 

PC Sewage Sludge Pollutant concentrations

Management practice certification and description

Site restriction certification and description (where

Class B pathogen requirements are met)

Pathogen reduction certification and description

Vector attraction reduction certification and description

✔

✔

✔

✔ 

✔ 

✔b

✔ 

✔ 

✔c

CPLR Sewage Sludge Pollutant concentrations

Management practice certification and description

Site restriction certification and description (if Class

B pathogen requirements are met)

Pathogen reduction certification and description

Vector attraction reduction certification and description

Other information:

- Certification and description of information

 gathered (information from the previous applier, 

 landowner, or permitting authority regarding the 

 existing cumulative pollutant load at the site from 

 previous sewage sludge applications)

- Site location

- Number of hectares

- Amount of sewage sludge applied

- Cumulative amount of pollutant applied (including 

 previous amounts)

- Date of application

✔

✔

✔

✔ 

✔ 

✔b

✔ 

✔ 

✔ 

✔ 

✔ 

✔ 

✔ 

✔ 

✔c

✔d

✔d

✔d

✔d

✔d

✔d

APLR Sewage Sludge Pollutant concentrations

Management practice certification and description

Pathogen reduction certification and description

Vector attraction reduction certification and description

The AWSAR for the sewage sludge

✔

✔

✔

 ✔ 

✔

✔ 

✔ 

✔ 

✔ 

✔

a

 Reporting responsibilities are only for treatment works with a design flow rate equal to or greater than 1 mgd, treatment works that

serve a population of 10,000 or greater, and Class I treatment works. b

 The preparer certifies and describes vector attraction reduction methods other than injection and incorporation of sewage sludge into the soil.

The applier certifies and describes injection or incorporation of sewage sludge into the soil. c

 Records that certify and describe injection or incorporation of sewage sludge into the soil do not have to be reported.

d

 Some of this information has to be reported when 90 percent or more of any of the CPLRs is reached at a site, if the applier is a Class I treatment

works, a treatment works serving a population of 10,000 or more, or a treatment works with a 1 mgd or greater design flow.

186
by analytical results for pathogens and indicator organisms and log books documenting operational parameters for sludge treatment units. The following paragraphs

discuss the types of records used to demonstrate compliance for each pathogen reduction alternative. A discussion of Class A and Class B alternatives is provided in

Chapter 3.

Class A Alternatives

Table 15-2 summarizes the recordkeeping requirements

for each Class A alternative.

Alternative 1: Thermally Treated Sewage Sludge

This alternative requires that sludge treatment units be

operated to maintain the sludge at a specific temperature for a specific period of time. To demonstrate compliance with the operational parameters, the preparer

should check the temperature in the sludge treatment

unit(s) and record it to demonstrate that the sludge was

held at a constant temperature for the required number

of days. If the temperature is not recorded continuously,

it should be checked and recorded during each work

shift or at least twice a day. The objective is to obtain

temperature readings that are representative of the temperature maintained throughout the treatment process.

In addition, records should document the detention time

of the sludge in the treatment unit, the daily input of

sludge, and the withdrawal of supernatant and processed sludge from the treatment unit. The size (gallons)

of the unit(s) should also be documented.

This alternative also requires documentation of monitoring for either Salmonella sp. bacteria or fecal coliform in

sewage sludge at the time of use. To this end, the

preparer should keep the records outlined in Figure 15-4

documenting sampling and analysis.

Alternative 2: Sewage Sludge Treated in a High pHHigh Temperature Process

Alternative 2, like Alternative l, requires the analysis of

sludge quality and the evaluation of operating parameters. As with Alternative 1, the sludge must be monitored

for either Salmonella sp. bacteria or fecal coliform. Use

of this alternative requires that operating logs be kept

that document pH, temperature, residence time, and

percent total solids. The temperature of the sewage

sludge should be checked and recorded to document it

is above 52°C for 12 continuous hours during the required 72-hour holding period. If the temperature is not

continuously monitored, it should be checked hourly

when feasible. At a minimum, it should be recorded at

the beginning, middle, and end of treatment. Similarly,

the pH of the sewage sludge should be recorded at the

beginning, middle, and end of the required 72-hour holding period. The percent total solids also should be determined for each batch. The preparer must keep the

records outlined in Figure 15-4 to document that sludge

was analyzed at the time of use or disposal for either

Salmonella sp. bacteria or fecal coliform at the frequency specified in Chapter 3, Table 3-15.

Parameters: Pollutant Concentrations (metals), Salmonella

sp. or Fecal Coliform bacteria, Percent Solids, Enteric

Viruses and Viable Helminth Ova (for certain pathogen

reduction alternatives)

• Sampling Records. Date and time of sample collection,

sampling location, sample type, sample volume, name of

sampler, type of sample container, and methods of

preservation, including cooling.

• Analytical Records. Date and time of sample analysis,

name of analyst, and analytical methods used.

• Raw Data. Laboratory bench sheets indicating all raw data

used in the analyses and the calculation of results (unless

a contract laboratory performed the analyses for the

preparer). 

• Name of contract laboratory, if applicable. 

• QA/QC. Sampling and analytical quality assurance/quality

control (QA/QC) procedures.

• Analytical results expressed in dry weight.

Figure 15-4. Required Records for Preparers of Sewage Sludge

to Document Sampling and Analysis (U.S. EPA,

1993b).

“I certify under penalty of law, that the [insert each of the following requirements that are met: Class A or Class B pathogen

requirements, vector attraction reduction requirements, management practices, site restrictions, requirements to obtain information] in

[insert the appropriate section number/s in Part 503 for each requirement met] have/have not been met. This determination has been

made under my direction and supervision in accordance with the system designed to ensure that qualified personnel properly gather

and evaluate the information used to determine that the requirements have been met. I am aware that there are significant penalties

for false certification, including the possibility of fine and imprisonment.”

Signature Date

Note: The exact language of the certification should be tailored to accurately describe which requirements have been met and which

 have not been met, when applicable.

Figure 15-5. Certification statement required for recordkeeping.

187
Table 15-2. Recordkeeping Recommendations for Class A Pathogen Reduction Alternatives (U.S. EPA, 1993b)

188
Alternative 3: Sewage Sludge Treated in Other 

Processes

Alternative 3, like the first two alternatives under Class

A, utilizes a combination of sludge quality analysis and

documentation of operating parameters. In addition to

monitoring for either fecal coliform or Salmonella sp.

bacteria under this alternative, preparers must monitor

for enteric viruses and viable helminth ova. If the

preparer follows the steps outlined in Figure 15-6, he or

she can substitute documentation of operating parameters for periodic analysis of enteric viruses and viable

helminth ova (U.S. EPA, 1993b). Regardless of how the

preparer demonstrates compliance with the enteric virus

and viable helminth ova requirement, the final sludge

must be sampled and analyzed at the time of use for

either fecal coliform or Salmonella sp. bacteria according to the frequency specified in Chapter 3, Table 3-15.

The preparer must maintain the records outlined in Figure 15-4 to document sludge sampling and analysis

before and after pathogen reduction treatment. These

records also must define the values used for operating

parameters between the before- and after-treatment

sludge analyses. If operating parameters are substituted

for periodic sludge monitoring, records must also document that these values are maintained consistently. The

specific operating parameters that must be recorded to

demonstrate compliance may vary depending on the

particular pathogen reduction process used (e.g., composting, pasteurization).

Alternative 4: Sewage Sludge Treated in Unknown

Processes

Alternative 4 relies solely on the analysis of sewage

sludge for pathogens (i.e., Salmonella sp. bacteria, enteric viruses, and viable helminth ova) and indicator

organisms (i.e., fecal coliform) to demonstrate pathogen

reduction. Records must document that these parameters were sampled and analyzed at least as often as

specified in the Part 503 regulation (see Chapter 3,

Figure 15-6. Pathogen reduction alternative 3—analysis and operation (U.S. EPA, 1993b).

189
Table 3-15). The preparer should keep the records outlined in Figure 15-4 for each sampling event.

Alternative 5: Use of a Process to Further Reduce

Pathogens (PFRP)

This alternative requires a combination of sludge analysis for either fecal coliform or Salmonella sp. bacteria

and documentation of operating parameters. The specific operating parameters that must be evaluated are

defined by the particular PFRPs. Table 15-2 outlines the

seven different PFRPs and the specific operating parameters for each. Records should include a description of the pathogen reduction process, documentation

of sampling and analysis of the sludge for fecal coliform

or Salmonella sp. bacteria (see Figure 15-4), and log

books documenting proper operation of pathogen reduction processes.

Alternative 6: Use of a Process Equivalent to a PFRP

Alternative 6 requires a combination of sludge analysis

and documentation of operating parameters. As with the

other Class A alternatives, the sludge must be monitored

for either fecal coliform or Salmonella sp. bacteria. Alternative 6 requires sewage sludge to be treated in a

process equivalent to a PFRP, as determined by the

permitting authority. The permitting authority should indicate appropriate information that has to be kept. The

records could include temperature in sludge treatment

units, retention time, pH, solids or moisture content, and

dissolved oxygen (DO) concentration.

Table 15-3. Recordkeeping Requirements for Class B Pathogen Reduction Alternatives (U.S. EPA, 1993b)

190
Class B Alternatives

Table 15-3 summarizes the recordkeeping requirements

for each Class B alternative.

Alternative 1: Monitoring of Fecal Coliform

Alternative 1 requires the analysis of the sewage sludge

for fecal coliform. In addition to maintaining the records

outlined in Figure 15-4 to document compliance with the

fecal coliform level, the preparer should maintain the

calculation of the geometric mean of the seven samples

analyzed under this alternative (see Alternative 1 in

Chapter 3).

Alternative 2: Use of a Process to Significantly Reduce

Pathogens (PSRP)

This alternative requires a combination of sewage

sludge analysis and documentation of operating parameters. As with the PFRP alternative, the specific

operating parameters that must be evaluated vary depending on the sludge treatment process used, as listed

in Table 15-3. Records should include a description of

the pathogen reduction process and log books documenting regular and frequent evaluations of the operating parameters.

Alternative 3: Use of a Process Equivalent to a PSRP

Alternative 3 requires sewage sludge to be treated in a

process equivalent to a PSRP, as determined by the

permitting authority. The permitting authority should

have specified the appropriate records to demonstrate

compliance with this alternative. The records could include temperature in sludge treatment units, retention

time, pH, solids or moisture content, and DO concentration.

15.6.2.3 Records of Vector Attraction Reduction

When sewage sludge is land applied, the Part 503

regulation requires a certification (see Figure 15-5) that

the vector attraction reduction requirements were met

and a description of how these requirements were

achieved. The description should be supported by documentation of process controls for treatment processes

that achieve vector attraction reduction. As with the

pollutant and pathogen records, this documentation

must be kept for 5 years.

There are 10 options to comply with the vector attraction

reduction requirements for land application. The first

eight apply to the sewage sludge and are performed by

the preparer (the final two are met at the land application

site). These eight options are referred to as the sludge

processing options and involve sludge treatment to reduce vector attraction characteristics. They are performed by preparers during or immediately after

pathogen reduction. Each of these processing options

is discussed in Chapter 3; the related records required

are described below.

Option 1: Reduction in Volatile Solids Content 

Under this option the preparer must demonstrate that

the volatile solid concentrations in sewage sludge are

reduced by 38 percent between the raw sludge and the

sewage sludge that is used or disposed. The preparer

needs to maintain records on the volatile solids content

(mg/kg) of the raw sludge and the sewage sludge that

is used or disposed, and the calculation of volatile solids

reduction. While most preparers evaluate these parameters regularly to document constant process operation, records must show that volatile solids reduction was

evaluated at least as frequently as specified in Table 3-15

in Chapter 3.

Option 2 and 3: Additional Digestion of Anaerobically and Aerobically Digested Sewage Sludge

Options 2 and 3 are methods to demonstrate that vector

attraction reduction is achieved even though 38 percent

volatile solids reduction was not attained (as required

under Option 1). The following records demonstrate that

options 2 and 3 are met:

• A description of the bench-scale digester and its

operation.

• The time (days) that the previously digested sludge

sample was further digested in the bench-scale

digester.

• The temperature (degrees Celsius) maintained in the

bench-scale digester for the time (days) the sample

was being further digested; the temperature should

either be recorded continuously or it should be

checked and recorded during each work shift or during at least two well-spaced intervals during each day.

• Volatile solids concentration of the sewage sludge in

mg/kg before and after bench-scale digestion.

Option 4: Specific Oxygen Uptake Rate (SOUR) for

Aerobically Digested Sewage Sludge 

The preparer should perform the SOUR test and record

the following information to demonstrate compliance under this option:

• Dissolved Oxygen (DO) readings of the sludge taken

at 1-minute intervals over a 15-minute period or until

the DO is reduced to 1 mg/L, and the average DO

value used in the SOUR calculation.

• Calibration records for the DO meter.

• Total solids determination for the sludge in g/L.

• Temperature (degrees Celsius) taken at the beginning and end of the procedure.

191
• Temperature correction to 20°C, if other temperatures

are used.

• Calculation of SOUR using the following equation:

SOUR =

oxygen consumption rate per minute (

DO mg/L

min )

total solids (g/L) (60 min/hour)

While most preparers evaluate this parameter regularly

to document constant process operation, the records

must demonstrate that the SOUR was evaluated at least

as frequently as specified in Chapter 3, Table 3-15.

Option 5: Aerobic Processes at Greater Than 40°C

Under this option, the preparer should record the following information to demonstrate compliance:

• Sludge residence time.

• Temperature (degrees Celsius) of the sewage sludge;

the temperature should either be recorded continuously or checked and recorded at least once per work

shift or at least twice a day over a 14 day period.

Option 6: Addition of Alkali Material

The preparer should maintain the following records to

document alkaline treatment under this option:

• pH (standard units) recorded at least at 0-, 2-, and

24-hour intervals of treatment.

• Duration of time (hours) that pH is maintained at or

above specified minimum levels.

• Amount (pounds or gallons) of alkali material added.

• Amount of sludge treated (e.g., gallons, kilograms).

Options 7 and 8: Moisture Reduction

Under these options, the preparer should determine

percent total solids for each batch of sludge and keep

the following records to demonstrate compliance:

• Results of solids analysis of sewage sludge prior to

mixing with other material (as dry weight) expressed

as percent of final sludge.

• Presence of unstabilized solids generated during primary treatment.

Records should demonstrate that the analysis of percent total solids was performed at least as frequently as

specified in Chapter 3, Table 3-15.

15.6.3 Part 503 Requirements for Appliers of

Sewage Sludge

For Part 503 requirements for appliers of sewage

sludge, see the Land Application of Sewage Sludge—

A Guide for Land Appliers on the Recordkeeping and

Reporting Requirements of the Federal Standards for

the Use and Disposal of Sewage Sludge Management

in 40 CFR Part 503 (U.S. EPA, 1994b).

15.6.4 Notification Requirements for Preparers

and Appliers of Sewage Sludge

When sewage sludge is prepared for land application in

bulk form or sold or given away in a bag or other

container for application to the land, the preparer must

inform the applier of the sewage sludge quality. The

notification requirements are different if the sludge is

sold or given away in a bag or other container rather

than being land applied in bulk, as described below. The

notice and necessary information requirement does not

apply when the sewage sludge or the material derived

from sewage sludge meets the “exceptional quality criteria” discussed in Chapter 3.

15.6.4.1 Bulk Sewage Sludge

When bulk sewage sludge that is not “exceptional quality” is prepared for land application, both the preparer

and the land applier have notification requirements. The

preparer must provide the following sewage sludge

quality information to the land applier:

• Pollutant concentrations.

• Nitrogen concentration (TKN, ammonia, and nitrate

nitrogen).

• Pathogen reduction level achieved (Class A or Class B).

• Vector attraction reduction option used (Options 1-8).

• Required management practices and recordkeeping.

The land applier must have this information to comply

with the Part 503 regulation when land applying the

sewage sludge. If the pollutants do not meet the pollutant concentration limits in Chapter 3, Table 3-4, then the

land applier must track the cumulative pollutant loading

rates. If a Class B pathogen reduction alternative was

used, then the land applier must ensure that the site

restrictions are met. If the preparer did not perform one

of the sludge processing vector attraction reduction options (Options 1-8), then the land applier must perform

one of the sludge management vector attraction reduction options (Options 9-10).

The land applier is also responsible for providing the

land owner or lease holder of the land notice and necessary information to comply with the Part 503 requirements. For example, if the sludge met Class B pathogen

reduction requirements, then the land owner or lease

holder must be informed of the associated site use and

access restrictions. If the land applier is tracking the

cumulative pollutant loading rates (see above paragraph), he or she should document and provide the land

owner or lease holder with the following information:

• Location of land application site.

192
• Date bulk sewage sludge was applied.

• Time bulk sewage sludge was applied if vector attraction reduction option 9 or 10 was used.

• Number of hectares where the sewage sludge was

applied.

• Amount of bulk sewage sludge applied.

Figure 15-7. Notice and necessary information (U.S. EPA, 1993b)

193
• Cumulative amount of each pollutant (i.e., kilograms)

applied.

The land owner or tenant may request specific information, such as analytical results on sludge quality or

documentation on how sludge management practices

are met. In general, the form in Figure 15-7 may be used

to satisfy the notification requirements of both the

preparer and the land applier.

15.6.4.2 Sewage Sludge Sold or Given Away in

a Bag or Other Container for

Application to the Land

When sewage sludge that does not meet the Part 503

pollutant concentration limits is sold or given away in a

bag or other container for application to the land, it must

be accompanied by a label or instruction sheet. The

label or instruction sheet must contain the following

information:

• Name and address of the person who prepared the

sewage sludge.

• Statement that land application is prohibited except

in accordance with the instructions.

• The annual whole sludge application rate that ensures that none of the annual pollutant loading rates

in Chapter 3, Table 3-4, are exceeded.

15.6.5 Notice of Interstate Transport

When bulk sewage sludge that does not meet the “exceptional quality” criteria is going to be applied to land

outside a state in which the sludge was prepared, the

preparer is required to provide written notice to the

permitting authority for the state in which the bulk sewage sludge is proposed to be applied, prior to the initial

application of the sewage sludge to a site. The written

notice must include the following information:

• Location, by either street address or latitude and longitude, of each land application site.

• Approximate time when bulk sewage sludge will be

applied to the site.

• Name, address, telephone number, and National Pollutant Discharge Elimination System (NPDES) permit

number for the person who prepares the bulk sewage

sludge.

• Name, address, telephone number, and NPDES permit number for the person who will apply the bulk

sewage sludge.

15.6.6 Notification by Appliers

The person who applies bulk sewage sludge subject to

the cumulative pollutant loading rates in Part

503.13(b)(2) to the land must provide written notice to

the permitting authority for the state in which the bulk

sewage sludge will be applied, including:

• The location, by either street address or latitude and

longitude, of the land application site.

• The name, address, telephone number, and NPDES

permit number for the person who will apply the bulk

sewage sludge.

15.6.7 Annual Reports

Most preparers are required by Part 503 to report annually to the permitting authority. Annual reports cover

information and data collected during the calendar year

(January 1 to December 31). Reports on sewage sludge

quality must include the results of monitoring pollutant

concentrations and pathogen levels, a description of

operating parameters for pathogen reduction and vector

attraction reduction, and certifications that pathogen and

vector attraction reductions were achieved. Permits issued by EPA or a state may contain additional reporting

requirements.

15.6.7.1 Persons Responsible for Submitting

Reports Under Part 503

Persons responsible for reporting annually are described in the Part 503 regulation as:

• Publicly owned treatment works (POTW) with an average design influent flow rate equal to or greater

than 1 million gallons per day.

• POTWs serving a population of 10,000 or more.

• Class I sludge management facilities.

Class I sludge management facilities include POTWs

required to have an approved pretreatment program or

that have elected to institute local limits, and treatment

works processing domestic sewage that EPA or the

state have classified as Class I because of the potential

for the use of sewage sludge to negatively affect public

health and the environment. Reports must be submitted

to the permitting authority (either EPA or a state with an

EPA-approved sludge management program).

15.6.7.2 Information Required in Annual Reports

The Part 503 regulation specifies the information

preparers are required to keep in their records. This

includes background information on the generation and

use of sludge; the results of sludge quality analysis; and

a description and certification for pathogen and vector

attraction reduction requirements (see Figure 15-5).

Specific information to be contained in annual reports

include the amount of sewage sludge generated, in

metric tons expressed as a dry weight (see Appendix D

for equations to convert sludge volume to metric tons);

the name and address of the preparer who will receive

194
the sludge next, if applicable; and the name and address

of the land applier if different from the generator.

The reporting requirements for pollutant limits include

submission of the analytical results from monitoring pollutant concentrations in the sewage sludge. Reports

should include the results of all analyses performed

during the reporting period using the prescribed analytical method(s) (see Chapter 13). Analytical results must

be reported as milligrams per kilogram (dry weight).

Reports should also indicate which analytical methods

were used, how frequently sludge was monitored, and

the types of samples collected.

Preparers also are required to submit a certification (see

Figure 15-5) and description of how the pathogen reduction requirements were met. A detailed description of the

pathogen reduction treatment process should include

the type of process used, standard operating procedures, a schematic diagram, and should identify specific

values for all operating parameters.

Finally, preparers are required to report information regarding vector attraction reduction when one of the sludge

processing options (Option 1-8). The report must contain

a description and certification (see Figure 15-5) that the

vector attraction reduction requirements were met.

The general certification statement that must be used by

preparers and appliers (Figure 15-5) certifies that,

among other things, the preparer or applier and his or

her employees are qualified to gather information and

perform tasks as required by the Part 503 rule. A person

is qualified if he or she has been sufficiently trained. The

certifier should periodically check the performance of his

or her employees to verify that the Part 503 requirements are being met. The preparer is required to keep

these records for 5 years for sewage sludge meeting

Part 503 pollutant concentration limits or annual pollutant loading rate limits, and the applier is required to keep

records for the life of the site (indefinitely) for sewage

sludge meeting Part 503 cumulative pollutant loading

rate limits. These required records may be requested for

review at any time by the permitting or enforcement

authority.

15.6.7.3 Submitting Annual Reports

As of 1994, annual reports required under Part 503 are

due February 19 every year. Annual reports must be

submitted to the Permitting Authority, which is the EPA

Regional Water Compliance Branch Chief until state

sludge management programs are delegated the responsibilities of the federal program.

15.7 References

When an NTIS number is cited in a reference, that

document is available from:

 National Technical Information Service

 5285 Port Royal Road

 Springfield, VA 22161

 703-487-4650

Burge, W. and P. Marsh. 1978. Infections, disease, hazards of land

spreading sewage wastes. Journal of Environmental Quality.

7(1):1-9.

Clark, C. et al. 1980. Occupational hazards associated with sludge

handling. In: Bitton, G. et al., eds. Health risks of land application.

Ann Arbor Science, pp. 215-244.

Elliott et al. 1990. Land application of water treatment plant sludges:

Impact and management. American Water Works Research Foundation, Denver, CO.

Kowal, N. 1983. An overview of public health effects. Presented at

Workshop on the utilization of municipal wastewater and sludge

on land, Denver, CO.

Pahren, H. et al. 1979. Health risks associated with land application

of municipal sludge. Journal of Water Pollution Control Federation,

Vol. 51, pp. 2588-2601.

U.S. EPA. 1994a. A plain English guide to the Part 503 biosolids rule.

EPA/832/R-93/003. Washington, D.C.

U.S. EPA. 1994b. Land application of sewage sludge—A guide for land

appliers on the recordkeeping and reporting requirements of the

federal standards for the use and disposal of sewage sludge management in 40 CFR Part 503. EPA/831/B-93/002b. Washington, DC.

U.S. EPA. 1993a. Biosolids management handbook for small to medium size POTWs. U.S. EPA Regions 8 and 10. (September 3).

U.S. EPA. 1993b. Preparing sewage sludge for land application or

surface disposal: A guide for preparers of sewage sludge on the

monitoring, record keeping, and reporting requirements of the federal standards for the use or disposal of sewage sludge, 40 CFR

Part 503. EPA/831/B-93/002a. Washington, DC.

U.S. EPA. 1992. Control of pathogens and vector attraction in sewage

sludge. EPA/625/R-92/013. Washington, DC.

U.S. EPA. 1985. Demonstration of acceptable systems for land disposal of sewage sludge. Cincinnati, OH. EPA/600/2-85/062. (NTIS

PB85-208874).

195
Chapter 16

Cost Estimate Guidance for Land Application Systems

16.1 Introduction

This chapter provides information on estimating costs for

sewage sludge land application systems. The cost algorithms presented are taken from EPA’s Handbook: Estimating Sludge Management Costs (U.S. EPA, 1985) and are

updated using (1994) cost indexes. The costs presented in

this chapter can be updated to later years by the reader

using the appropriate cost indexes (discussed below). The

algorithms cover both capital costs and annual operating

and maintenance (O&M) costs for land application at agricultural, forest, and land reclamation sites, as well as for

transportation (truck hauling and pipeline transport) of

sewage sludge to land application sites and onsite.

Certain key sludge management costs are not included in

this chapter, such as costs of sludge storage (e.g., lagoons, tanks, piles) and sludge treatment (e.g., stabilization, dewatering, composting). This information must be

added to land application costs if total sludge management

costs are to be accurately represented. The reader should

refer to EPA’s 1985 cost estimation handbook cited above

for sludge treatment and storage cost information.

The cost estimation algorithms present a logical series

of calculations using site-specific, process design, and

cost data for deriving base capital and base annual

operation and maintenance costs. Default values are

provided for many calculations. Most of the algorithms

can be hand-calculated in less than 20 minutes per trial.

Design parameters presented are “typical values” intended to guide the user; the more accurate design

information to which a user has access, the more accurate the resulting costs. 

The cost algorithms generally cover a range up to

100 million gallons of sludge per year, which is approximately equivalent to a wastewater treatment

plant of at least 50 mgd. This range was selected to

include plants where supplemental cost information

might be most useful.

16.1.1 Information Needed Prior to Using

Cost Algorithms

Before using the cost algorithms in this chapter, the

reader must obtain certain data and perform the preliminary steps described below; otherwise, the resulting

cost estimates may be over- or underestimated. 

• Develop a sludge management process chain that

shows the sequence of processes to be used, starting with the raw sludge and ending with final land

application practice.

• Develop a mass balance of sludge volume and

sludge concentration entering and leaving each process. This is necessary because many of the cost

algorithms in this chapter require as input data the

volume and the suspended solids content of the

sludge entering the process (which often is not the

raw sludge solids concentration). Thus, an approximate mass balance must first be computed to obtain

the sludge volume and sludge solids concentration

entering and leaving each process (e.g., treatment).

The volume of raw sludge usually is not the same as the

volume of final treated sludge leaving a treatment process, because each successive treatment process generally tends to reduce the mass and volume of sludge.

Therefore, the mass and volume of the final treated

sludge is typically only a fraction of the initial raw sludge

volume. Similarly, the sludge solids concentration

changes as the sludge proceeds through a series of

treatment processes. The steps involved in performing

a mass balance are described in EPA’s 1985 cost handbook (U.S. EPA, 1985).

After completing the mass balance procedure, the

reader may use the cost algorithms in this chapter to

estimate the base capital cost and base annual O&M

cost for different land application practices.

16.1.2 Economic Variables

16.1.2.1 Use of Indices for Inflation Adjustment

Numerous estimates of the costs of facility construction,

site preparation, and equipment purchase were developed by the authors of EPA’s 1985 cost handbook (U.S.

EPA, 1985). The base year for these costs, however,

was 1984; hence it is necessary to adjust these estimates to reflect 1994 price levels and costs. For construction-related costs, the standard index used is the

197
Engineering News Record Construction Cost Index

(ENRCCI). The ratio of the 1994 to 1984 index number

is used here to adjust construction-related cost items.

For equipment purchase costs, the 1984 prices have been

inflated using the Marshall and Swift Equipment Cost Index (MSECI). The ratio of the 1994 to 1984 index number

is used here to adjust equipment-related cost items.

Adjustment for inflation can be made to the following

cost algorithms using:

• The ENRCCI for total base capital costs and total base

annual O&M costs. The ENRCCI appears weekly in

Engineering News Record, published by McGraw Hill,

Inc. (Base 1994 ENRCCI index is 5,445.83.)

• The MSECI to adjust equipment costs or combined

costs in which equipment is the major cost component. MSECI is available from Chemical Engineering

magazine. (Base 1994 MSECI index is 990.8.)

16.1.2.2 Labor Rates

The 1985 EPA cost handbook assumed an hourly wage

of $13.00 for operators of heavy equipment which requires considerable skill and training. This rate has been

inflated to 1994 levels using the ENRCCI index, and

adjusted using a factor of 1.3 to account for non-wage

benefits paid by the employer. The effective wage rate,

therefore, is $22.97 per hour.

16.1.2.3 Cost of Diesel Fuel

Diesel fuel costs are assumed to average $1.09 per

gallon, based on average end-user prices for 1994 obtained from the September 12, 1994 edition of Oil and

Gas Journal.

16.1.3 Total Base Capital Cost Estimates

Total base capital costs (TBCC) for sewage sludge land

application systems in this chapter include sludge application vehicles, lime addition, grading, brush clearance,

facilities, and acreage required. Costs for engineering

design, construction supervision, legal and administration expenses, interest during construction, and contingencies are not included. These non-construction costs

must be estimated and added to the process TBCC

costs derived from the cost algorithms to estimate the

total project construction cost.

16.1.4 Total Annual O&M Cost Estimates

The annual O&M costs for sewage sludge land application

in this chapter do not include costs for administration and

laboratory sampling/analysis. These costs must be estimated and added to the process O&M costs derived from

the cost algorithms to obtain the total estimated annual O&M

cost. Total annual O&M costs can be 30 percent higher than

the costs derived from the algorithms in this chapter.

The total estimated O&M cost calculations in this chapter

also do not include revenues generated through the sale

and/or use of sludge, composting products, or sludge byproducts (i.e., methane produced in anaerobic digestion). If

the user has information available on revenues generated

through usage or sale, O&M costs may be decreased by

subtracting any revenues generated on an annual basis

from the fixed annual O&M cost for that process.

16.1.5 Calculating Cost Per Dry Ton

In sludge processing, it is often desirable to express costs

in terms of annual cost per dry ton. This cost is obtained

by summing the amortized capital cost and base annual

O&M costs and dividing by the annual dry sludge solids

processed (TDSS, as presented in Calculation #1 for agricultural, forest, and reclamation sites later in this chapter)

and then performing the following calculation:

CPDT = (ACC + COSTOM)/TDSS

where:

CPDT = Cost per dry ton, $/ton.

ACC = Annual amortized capital cost, $/yr

COSTOM = Base annual O&M cost, $/yr.

TDSS = Dry solids applied to land, Tons/yr.

If information on salvage values and revenues generated from sludge usage is available, it can be subtracted

from the numerator in the above equation.

16.2 Agricultural Land Application

16.2.1 General Information and

Assumptions Made

The cost algorithms for agricultural land application of

sewage sludge presented below assume that the sewage

sludge application vehicles at the application site are not

the same vehicles which transported the sludge from the

treatment plant to the application site. In many cases,

however, the same vehicle is used to both transport sewage sludge and apply it to the application site. If the same

vehicle is used for sludge transport and application, then

a zero value should be used for the cost of the onsite

sludge application vehicle (the COSTPV factor) since the

cost of that vehicle has already been included in the

previous sludge hauling process.

The cost algorithms for agricultural land application below

include calculations for the costs of land, lime addition, and

site grading. At many agricultural land application sites,

however, all or some of these costs are not applicable

to the municipality, since these factors are either unnecessary or paid for by the farmer. If the latter applies, a

zero value should be used in the cost algorithms, where

appropriate.

198
Operation and maintenance (O&M) costs include labor,

diesel for the operation of vehicles, vehicle maintenance, and site maintenance.

If the farm(s) accepting sewage sludge for agricultural

land application are numerous and widespread, an expensive and complicated sludge distribution system

may be required.

16.2.2 Process Design and Cost Calculations

(1) Calculate dry solids applied to land per year.

TDSS = [(SV)(8.34)(SS)(SSG)(365)]/(2,000)(100)

where:

TDSS = Dry solids applied to land, Tons/yr.

SV = Daily sludge volume, gpd.

SS = Sludge suspended solids concentration, percent.

SSG = Sludge specific gravity, unitless. If

an input value is not available, default value can be calculated using

the following equation:

SSG = 1/[(100 - SS)/100) + (SS)/(1.42)(100)]

where:

1.42 = Assumed sludge solids specific

gravity, unitless.

8.34 = Density of water, lb/gal.

2,000 = Conversion factor, lb/Ton.

(2) Sludge application area required.

SDAR = (TDSS)/(DSAR)

where:

SDAR = Farm area required for sludge application, ac.

TDSS = Dry solids applied to land, Tons/yr

(see Calculation #1 above).

DSAR = Average dry solids application

rate, Tons of dry solids/ac/yr. 

This value normally ranges from 

3 to 10 for typical food chain crop

growing sites depending on crop

grown, soil conditions, climate,

and other factors. Default value =

5 Tons/ac/yr. (See Chapter 7.) 

(3) Hourly sludge application rate.

HSV = (SV)(365)/(DPY)(HPD)

where:

HSV = Hourly sludge application rate, gal/hr.

SV = Daily sludge volume, gpd. (See Calculation #1 above.)

DPY = Annual sludge application period,

days/yr. This value normally ranges

from 100 to 140 days/yr depending

on climate, cropping patterns, and

other factors. See Table 16-1 for

typical values. Default value = 120

days/yr.

HPD = Daily sludge application period,

hr/day. This value normally ranges

from 5 to 8 hr/day depending on

equipment used, proximity of application sites, and other factors. Default value = 6 hr/day.

(4) Capacity of onsite mobile sludge application vehicles.

It is assumed that the sludge has already been transported to the private farm land application site by a

process such as a large-haul vehicle, etc. The onsite

mobile application vehicles accept the sludge from the

transport vehicle, pipeline, or onsite storage facility, and

proceed to the sludge application area to apply the

sludge. Typical onsite mobile sludge application vehicles at farm sites have capacities ranging from 1,600 to

4,000 gal, in the following increments: 1,600, 2,200,

3,200, and 4,000 gal.

(4a) Capacity and number of onsite mobile sludge application vehicles. 

The capacity and number of onsite mobile sludge application vehicles required is determined by comparing the

hourly sludge volume, (HSV), with the vehicle sludge

handling rate, (VHRCAP), as shown in Table 16-2.

Above 26,000 gal/hr, the number of 4,000-gal capacity

vehicles required is calculated by:

NOV = HSV/6,545 (round to the next highest integer)

where:

NOV = Number of onsite sludge application

vehicles.

HSV = Hourly sludge application rate,

gal/hr (see Calculation #3).

Table 16-1. Typical Days Per Year of Food Chain Crop

Sludge Application

Geographic Region

Typical Days/Yr 

of Sludge Application

Northern U.S. 100

Central U.S. 120

Sunbelt States 140

199
(4b) Average round trip onsite cycle time for mobile

sludge application vehicles.

CT = [(LT) + (ULT) + (TT)]/0.75

where:

CT = Average round trip onsite cycle

time for mobile sludge application

vehicle, min.

LT = Load time, min, varies with vehicle

size (see Table 16-3).

ULT = Unload time, min, varies with vehicle size (see Table 16-3).

TT = Onsite travel time to and from

sludge loading facility to sludge application area, min (assumed values are shown in Table 16-3).

0.75 = An efficiency factor.

(4c) Single vehicle sludge handling rate. 

The actual hourly sludge throughput rates for an onsite mobile sludge application vehicle is dependent on

the vehicle tank capacity, the cycle time, and an efficiency factor.

VHRCAP = [(CAP)(60)(0.9)]/(CT)

where:

VHRCAP = Single vehicle sludge handling rate,

gal/hr.

CAP = Vehicle tank capacity, gal.

0.9 = Efficiency factor.

Table 16-4 shows VHRCAP values for typical size vehicles.

(5) Total land area required.

For virtually all sludge-to-cropland applications, a larger

land area is required than that needed only for sludge

application (SDAR). The additional area may be required for changes in cropping patterns, buffer zones,

onsite storage, wasted land due to unsuitable soil or

terrain, and/or land available in the event of unforeseen

future circumstances. The additional land area required

is site-specific and varies significantly (e.g., from 10 to

100 percent of the SDAR).

TLAR = (1 + FWWAB)(SDAR)

where:

TLAR = Total land area required for agricultural land application site, ac.

FWWAB = Fraction of farmland area needed in

addition to actual sludge application

area, e.g., buffer zones, unsuitable

soil or terrain, changes in cropping

patterns, etc. Default value = 0.4.

SDAR = Farm area required for sludge application, ac (see Calculation #2.)

(6) Lime addition required for soil pH adjustment to a

value of at least 6.5.

TLAPH = (FRPH)(SDAR)

where:

TLAPH = Total land area requiring lime addition, ac.

FRPH = Fraction of crop growing area requiring lime addition to raise pH

to 6.5. Depending on the natural

Table 16-2. Capacity and Number of Onsite Mobile Sludge

Application Vehicles Required

Hourly Sludge

Application

Rate (HSV)

Vehicle Number of Each Capacity (NOV)

Capacity (CAP) (gal)

HSV (gal/hr) 1,600 2,200 3,200 4,000

 0 - 3,456 1 - - -

 3,456 - 4,243 - 1 - -

 4,243 - 5,574 - - 1 -

 5,574 - 6,545 - - - 1

 6,545 - 8,500 - 2 - -

 8,500 - 11,200 - - 2 -

11,200 - 13,100 - - - 2

13,100 - 19,600 - - - 3

19,600 - 26,000 - - - 4

Table 16-3. Vehicle Load, Unload, and Onsite Travel Time

Vehicle Capacity (CAP)

(gal)

LTa

(min)

ULTa

(min)

TTa

(min)

CTa

(min)

1,600 6 8 5 25

2,200 7 9 5 28

3,200 8 10 5 31

4,000 9 11 5 33

a

 LT = Loading time.

 ULT = Unloading time.

 TT = Onsite travel time.

 CT = Average round-trip onsite cycle time.

Table 16-4. Vehicle Sludge Handling Capacity

Vehicle Capacity (CAP) (gal) VHRCAPa (gal/hr)

1,600 3,456

2,200 4,243

3,200 5,574

4,000 6,545

a

 VHRCAP = Single vehicle sludge handling rate.

200
pH of local soils, this fraction can

vary from 0 to 1. Default value = 0.5.

SDAR = Farm area required for sludge application, ac (see Calculation #2.)

(7) Total land area requiring light grading. 

Typical agricultural land used for growing crops is usually

already graded to even slopes. However, when sewage

sludge is added to the soil, additional light grading may be

necessary to improve drainage control and minimize runoff

of sludge solids. This need is site-specific.

TLARLG = (FRLG)(SDAR)

where:

TLARLG = Total land area requiring light grading, ac.

FRLG = Fraction of crop-growing area requiring light grading for drainage control. Depending on local conditions

at the sludge application sites this

fraction can vary from 0 to 1. Default value = 0.3.

SDAR = Farm area required for sludge application, ac (see Calculation #2.)

(8) Annual operation labor requirement.

L = 8 (NOV)(DPY)/0.7

where:

L = Annual operation labor requirement, hr/yr.

NOV = Number of onsite sludge application

vehicles (see Calculation #4).

DPY = Annual sludge application period,

days/yr (see Calculation #3).

8 = Hr/day assumed.

0.7 = Efficiency factor.

(9) Annual diesel fuel requirement for onsite mobile

sludge application vehicles.

FU = (HSV)(HPD)(DPY)(DFRCAP)/(VHRCAP)

where:

FU = Annual diesel fuel usage, gal/yr.

HSV = Hourly sludge application rate,

gal/hr (see Calculation #3).

HPD = Daily sludge application period,

hr/day (see Calculation #3).

DPY = Annual sludge application period,

days/yr (see Calculation #3).

DFRCAP = Diesel fuel consumption rate

(gal/hr); for specific capacity vehicle, see Table 16-5.

VHRCAP = Vehicle sludge handling rate (see

Calculation #4).

(10) Cost of land.

COSTLAND = (TLAR)(LANDCST)

where:

COSTLAND= Cost of land, $.

TLAR = Total land area required for agricultural land application site, ac (see

Calculation #5).

LANDCST = Cost of land, $/ac. Default value =

0. It is assumed that application

of sludge is to privately owned

farm land. 

(11) Cost of lime addition to adjust pH of soil.

COSTPHT = (TLAPH)(PHCST)

where:

COSTPHT = Cost of lime addition, $.

TLAPH = Total land area requiring lime addition, ac (see Calculation #6)

PHCST = Cost of lime addition, $/ac. Default

value = $82/acre (ENRCCI/5,445.83);

assumes 2 Tons of lime/ac requirement.

(12) Cost of light grading earthwork.

COSTEW = (TLARLG)(LGEWCST)

where:

COSTEW = Cost of earthwork grading, $.

TLARLG = Total land area requiring light grading, ac (see Calculation #7)

LGEWCST = Cost of light grading earthwork,

$/ac. Default value = $1,359/ac.

(ENRCCI/5,445.83).

(13) Cost of onsite mobile sludge application vehicles. 

Note: If same vehicle is used both to transport sludge to the

site and to apply sludge to the land, then COSTMAV = 0.

COSTMAV = (NOV)(COSTPV) MSECI

990.8

where:

COSTMAV = Cost of onsite mobile sludge application vehicles, $.

Table 16-5. Gallons of Fuel Per Hour for Various Capacity

Sludge Application Vehicles

Vehicle Capacity (CAP) (gal) DFRCAPa (gal/hr)

1,600 3.5

2,200 4 

3,200 5 

4,000 6 

a

 DFRCAP = Diesel fuel consumption rate.

201
NOV = Number of onsite sludge application

vehicles (see Calculation #4).

COSTPV = Cost of onsite mobile sludge application vehicle, obtained from

Table 16-6.

MSECI = Current Marshall and Swift Equipment Cost Index at time analysis is

made.

(14) Annual cost of operation labor.

COSTLB = (L)(COSTL)

where:

COSTLB = Annual cost of operation labor, $/yr. 

L = Annual operation labor required, hr/yr.

COSTL = Cost of operation labor, $/hr. Default value = $22.97/hr.

(ENRCCI/5,445.83).

(15) Annual cost of diesel fuel.

COSTDSL = (FU)(COSTDF)

where:

COSTDSL = Annual cost of diesel fuel, $/yr.

FU = Annual diesel fuel usage, gal/yr.

COSTDF = Cost of diesel fuel, $/gal. Default

value = $1.09/gal.

(ENRCCI/5,445.83).

(16) Annual cost of maintenance for onsite mobile

sludge application vehicles.

VMC = 

[(HSV)(HPD)(DPY)(MCSTCAP)/(VHRCAP)] MSECI

990.8

where:

VMC = Annual cost of vehicle maintenance, $/yr.

HSV = Hourly sludge application rate,

gal/hr (see Calculation #3).

HPD = Daily sludge application period,

hr/day (see Calculation #3).

DPY = Annual sludge application period,

days/yr (see Calculation #3).

MCSTCAP = Maintenance cost, $/hr of operation; for specific capacity of vehicle,

see Table 16-7.

VHRCAP = Vehicle sludge handling rate (see

Calculation #4).

MSECI = Current Marshall and Swift Equipment

Cost Index at time analysis is made.

(17) Annual cost of maintenance for land application site

(other than vehicles) including monitoring, recordkeeping, etc.

SMC = [(TLAR)(16)] ENRCCI

5,445.83

where:

SMC = Annual cost of maintenance (other

than vehicles), $/yr.

TLAR = Total land area required for land 

application site, ac (see Calculation

#5).

16 = Annual maintenance cost, $/ac.

ENRCCI = Current Engineering News Record

Construction Cost Index at time

analysis is made.

(18) Total base capital cost.

TBCC = COSTLAND + COSTPHT + COSTEW

+ COSTMAV

where:

TBCC = Total base capital cost of agricultural land application program using

onsite mobile sludge application

vehicles, $.

COSTLAND= Cost of land for sludge application

site, $ (see Calculation #10).

COSTPHT = Cost of lime addition, $ (see Calculation #11).

COSTEW = Cost of light grading earthwork, $

(see Calculation #12) .

COSTMAV = Cost of onsite mobile sludge application vehicles, $ (see Calculation #13).

Table 16-6. Cost of Onsite Mobile Sludge Application

Vehicles 

Vehicle Capacity (CAP) (gal)

Cost Per Vehicle

(COSTPV) (1994 $)a

1,600 112,000

2,200 125,000

3,200 158,000

4,000 185,000

a

 Costs were taken from EPA’s 1985 Cost Estimation Handbook (U.S.

EPA, 1985) and inflated to 1994 price levels using the MSECI.

Table 16-7. Hourly Maintenance Cost for Various Capacities

of Sludge Application Vehicles

Vehicle Capacity (CAP)

(gal)

Maintenance Cost (MCSTCAP)

($/hr, 1994 $)a

1,600 6.40

2,200 7.01

3,200 7.86

4,000 9.45

a

 Costs were taken from EPA’s 1985 Cost Estimation Handbook (U.S.

EPA, 1985) and inflated to 1994 price levels using the MSECI.

202
(19) Total annual operation and maintenance cost.

COSTOM = COSTLB + COSTDSL + VMC + SMC

where:

COSTOM = Total annual operation and maintenance cost for agricultural land application program using onsite mobile

sludge application vehicles, $/yr.

COSTLB = Annual cost of operation labor, $/yr

(see Calculation #14).

COSTDSL = Annual cost of diesel fuel, $/yr (see

Calculation #15).

VMC = Annual cost of vehicle maintenance, $/yr (see Calculation #16).

SMC = Annual cost of site maintenance,

$/yr (see Calculation #17).

16.3 Application to Forest Lands 

16.3.1 General Information and

Assumptions Made

The cost algorithms presented below for forest land

application estimate only the cost of sewage sludge

application at the forest site using specially designed

onsite liquid sludge application vehicles. It is assumed

that the sludge is transported to the site by one of the

transportation processes discussed in Section 16.5.

Typically, the onsite liquid sludge application vehicles will

obtain sludge from a large “nurse” truck, or an on-site

sludge storage facility. These cost algorithms assume

that liquid sludge is applied by means of specially designed tanker trucks equipped with a spray “cannon”

having a range of approximately 100 ft.

Unlike agricultural land application which usually involves annual sewage sludge application, forest land

application to a specific site is often done at multi-year

intervals, e.g., every 5 years, which will influence costs.

In addition, forest land sites are usually less accessible

to sludge application vehicles than cropland, and on-site

clearing and grading of access roads is often an initial

capital cost. Provisions for estimating the cost of clearing brush and trees and grading rough access roads,

which are often paid by the land owner, are included in

these cost algorithms. 

While provision is made in the cost algorithms for including land costs, the municipality generally will not

purchase or lease the application site, and land cost will

be zero.

Base capital costs include (where appropriate) the cost

of land, clearing brush and trees, grading, and mobile

sludge application vehicles. Base annual O&M costs

include labor, diesel fuel for vehicles, vehicle maintenance, and site maintenance.

16.3.2 Process Design and Cost Calculations

(1) Calculate dry solids applied to land per year.

TDSS = [(SV)(8.34)(SS)(SSG)(365)]/(2,000)(100)

Same as Calculation #1 for agricultural land application

(see Section 16.2 above).

(2) Sludge application area required.

SDAR = (TDSS)(FR)/(DSAR)

where:

SDAR = Site area required for sludge application, ac.

TDSS = Dry solids applied to land, Tons/yr

(from Calculation #1).

FR = Frequency of sludge application to forest land at dry solids application rate

(DSAR) (i.e., period between application of sludge to some forest land

area), yr. This value varies depending

on tree species, tree maturity, whether

trees are grown for commercial purposes, and other factors. Default

value = 5 yr.

DSAR = Average dry solids application rate,

Tons of dry solids/ac. This value normally ranges from 20 to 40 for typical

forest land sites depending on tree

species, tree maturity, soil conditions,

and other factors. Default value = 20

Tons/ac/yr. (See Chapter 8.)

(3) Hourly sludge volume which must be applied.

HSV = (SV)(365)/(DPY)(HPD)

where:

HSV = Hourly sludge volume during application period, gal/hr.

SV = Daily sludge volume, gpd. (See Calculation #1.)

DPY = Annual sludge application period,

days/yr. This value normally ranges

from 130 to 180 days/yr for forest

land sites depending on climate,

soil conditions, and other factors.

Default value = 150 days/yr.

HPD = Daily sludge application period,

hr/day. This value normally ranges

from 5 to 8 hr/day depending on

equipment used, site size, and other

factors. Default value = 7 hr/day.

(4) Capacity of onsite mobile sludge application vehicles.

It is assumed that the sludge has already been transported to the forest land application site by a transport

203
process such as truck hauling. The onsite mobile application vehicles accept the sludge from a large nurse

truck, on-site storage facility, etc., and proceed to the

sludge application area to apply the sludge. Typical

onsite mobile sludge application vehicles at forest

land sites are specially modified tank trucks equipped

with a sludge cannon to spray the sludge at least 100

ft through a 240-degree horizontal arc. The application vehicle is modified to handle steep slopes, sharp

turn radius, and doze through small trees and brush.

Such vehicles can negotiate much rougher terrain,

e.g., logging roads, than conventional road tanker

trucks. Because of the special conditions encountered

in forest land sludge application, it is assumed that the

largest onsite sludge application vehicle feasible has

a capacity of 2,200 gal of sludge. Only two capacity

increments are included in this program, i.e., 1,000

gal and 2,200 gal.

(4a) Capacity and number of onsite mobile sludge application vehicles.

The capacity and number of onsite mobile sludge application vehicles required is determined by comparing the

hourly sludge volume, HSV, with the vehicle sludge

handling rate, VHRCAP, as shown in Table 16-8.

Above 7,584 gal/hr, the number of 2,200-gal capacity

vehicles required is calculated by:

NOV = HSV/2,528 (round to the next highest integer)

where:

NOV = Number of onsite mobile sludge application vehicles.

HSV = Hourly sludge volume during application period, gal/hr (see Calculation #3).

(4b) Average round trip on-site cycle time for mobile

sludge application vehicles.

CT = [(LT) + (ULT) + (TT)]/0.75

where:

CT = Average round trip on-site cycle

time for mobile sludge application

vehicle, min.

LT = Load time, min, varies with vehicle

size (see Table 16-9).

ULT = Unload time, min, varies with vehicle size (see Table 16-9).

TT = On-site travel time to and from

sludge loading facility to sludge application area, min (assumed values are shown in Table 16-9).

0.75 = An efficiency factor.

(4c) Single vehicle sludge handling rate. 

The actual hourly sludge throughput rates for an onsite

mobile sludge application vehicle is dependent on the

vehicle tank capacity, the cycle time, and an efficiency

factor.

VHRCAP = [(CAP)(60)(0.9)]/(CT)

where:

VHRCAP = Single vehicle sludge handling rate,

gal/hr.

CAP = Capacity of onsite mobile sludge application vehicle, gal.

0.9 = Efficiency factor.

Table 16-10 shows VHRCAP values for typical size

vehicles.

Table 16-8. Capacity and Number of Onsite Mobile Sludge

Application Vehicles Required

Vehicle Number of Each Capacity

(NOV) Capacity (CAP) (gal)

HSVa

 (gal/hr) 1,000 2,200

 0 - 1,317 1 -

1,317 - 2,528 - 1

2,528 - 5,056 - 2

5,056 - 7,584 - 3

a

 Hourly sludge volume during application period.

Table 16-9. Vehicle Load, Unload, and Onsite Travel Timea

Vehicle Capacity,

CAP (gal)

LT

(min)

ULT

(min)

TT

(min)

CT

(min)

1,000 6 8 10 32

2,200 7 9 10 35

a

 LT = Loading time.

 ULT = Unloading time.

 TT = Onsite travel time.

 CT = Average round-trip onsite cycle time.

Table 16-10. Vehicle Sludge Handling Capacity

Vehicle Capacity, (CAP) (gal) VHRCAPa (gal/hr)

1,000 1,317

2,200 2,528

a

 VHRCAP = Single vehicle sludge handling rate.

204
(5) Total land area required.

For virtually all forest land sites, a larger land area

is required than that needed only for sludge application (SDAR). The additional area may be required

for buffer zones, on-site roads, on-site storage,

wasted land due to unsuitable soil or terrain, etc.

The additional land area required is site-specific

and varies significantly, e.g., from 10 to 50 percent

of the SDAR.

TLAR = (1 + FWWAB)(SDAR)

where:

TLAR = Total land area required for forest

land site, ac.

FWWAB = Fraction of forest land site area

used for purposes other than

sludge application, e.g., buffer

zone, internal roads, sludge storage, waste land, etc. Varies significantly depending on site-specific

conditions. Default value = 0.2 for

forest land sites.

SDAR = Site area required for sludge application, ac (see Calculation #2).

(6) Clearing of brush and trees required. 

Often a forest land site will require clearing brush and

trees in access road areas to allow access by the sludge

application vehicle.

TLAWB = (FWB)(TLAR)

where:

TLAWB = Total land area with brush and

trees to be cleared, ac.

FWB = Fraction of forest land site area requiring clearing of brush and trees

to allow access by application vehicle. Varies significantly depending

on site-specific conditions. Default

value = 0.05 for forest land sites.

TLAR = Total land area required for forest

land site, ac (see Calculation #5).

(7) Earthwork required. 

Often a forest land application site will require grading

of access roads for the sludge application vehicles, to

provide drainage control, etc. The extent of grading

required is site-specific.

TLARG = (FRG)(TLAR)

where:

TLARG = Total land area requiring grading, ac.

FRG = Fraction of land area requiring

grading of access roads to allow

travel by sludge application vehicle, etc. Varies significantly depending on site-specific

conditions. Default value = 0.05

for forest land sites.

TLAR = Total land area required for forest

land site, ac (see Calculation #5).

(8) Annual operation labor requirement.

L = 8 (NOV)(DPY)/0.7

where:

L = Annual operation labor requirement,

hr/yr.

8 = Hr/day assumed.

NOV = Number of onsite sludge application

vehicles (see Calculation #4).

DPY = Annual sludge application period,

days/yr (see Calculation #3). 

0.7 = Efficiency factor.

(9) Annual diesel fuel requirement for onsite mobile

sludge application vehicles.

FU = (HSV)(HPD)(DPY)(DFRCAP)/(VHRCAP)

where:

FU = Annual diesel fuel usage, gal/yr.

HSV = Hourly sludge application rate,

gal/hr (see Calculation #3).

HPD = Daily sludge application period,

hr/day (see Calculation #3).

DPY = Annual sludge application period,

days/yr (see Calculation #3 above).

DFRCAP = Diesel fuel consumption rate

(gal/hr); for specific capacity vehicle

(see Table 16-11).

VHRCAP = Vehicle sludge handling rate (see

Calculation #4).

Table 16-11. Gallons of Fuel Per Hour for Various Capacity

Sludge Application Vehicles

Vehicle Capacity, (CAP) (gal) DFRCAPa (gal/hr)

1,000 3

2,200 4

a

 DFRCAP = Diesel fuel consumption rate.

205
(10) Cost of land for forest land application site.

COSTLAND = (TLAR)(LANDCST)

where:

COSTLAND= Cost of land for forest land site, $.

TLAR = Total land area required for forest

land site, ac. (see Calculation #5)

LANDCST = Cost of land, $/ac. Usually the forest land is not purchased by the

municipality. Default value = 0.

(11) Cost of clearing brush and trees.

COSTCBT = (TLAWB)(BCLRCST)

where:

COSTCBT = Cost of clearing brush and trees, $.

TLAWB = Total land area with brush and

trees to be cleared, ac (see Calculation #6).

BCLRCST = Cost of clearing brush and trees,

$/ac. Default value = $1,359/acre

(ENRCCI/5,445.83).

(12) Cost of grading earthwork.

COSTEW = (TLARG)(GEWCST)

where:

COSTEW = Cost of earthwork grading, $.

TLARG = Total land area requiring grading,

ac (see Calculation #7).

GEWCST = Cost of grading earthwork, $/ac. Default value = $2,039/acre

(ENRCCI/5,445.83).

(13) Cost of onsite mobile sludge application vehicles.

COSTMAV = [(NOV)(COSTPV)] MSECI

990.8

where:

COSTMAV = Cost of onsite mobile sludge application vehicles, $.

NOV = Number of onsite sludge application

vehicles (see Calculation #4).

COSTPV = Cost/vehicle, obtained from Table

16-12.

MSECI = Current Marshall and Swift Equipment Cost Index at time analysis is

made.

(14 ) Annual cost of operation labor.

COSTLB = (L)(COSTL)

where:

COSTLB = Annual cost of operation labor, $/yr.

L = Annual operation labor requirement,

hr/yr (see Calculation #8).

COSTL = Cost of operational labor, $/hr. Default value = $22.97/hr

(ENRCCI/5,445.83).

(15) Annual cost of diesel fuel.

COSTDSL = (FU)(COSTDF)

where:

COSTDSL = Annual cost of diesel fuel, $/yr.

FU = Annual diesel fuel usage, gal/yr

(see Calculation #9).

COSTDF = Cost of diesel fuel, $/gal. Default

value = $1.09/gal (ENRCCI/5,445.83).

(16) Annual cost of maintenance of onsite mobile sludge

application vehicles.

VMC = 

[(HSV)(HPD)(DPY)(MCSTCAP)/(VHRCAP)] MSECI

990.8

where:

VMC = Annual cost of vehicle maintenance, $/yr.

HSV = Hourly sludge application rate,

gal/hr (see Calculation #3).

HPD = Daily sludge application period,

hr/day (see Calculation #3).

DPY = Annual sludge application period,

days/yr (see Calculation #3).

MCSTCAP = Maintenance cost, $/hr of operation

for specific capacity of vehicle; see

Table 16-13.

MSECI = Current Marshall and Swift Equipment Cost Index at time analysis is

made.

Table 16-12. Cost of On-Site Mobile Sludge Application

Vehicles (1994)

Vehicle Capacity, (CAP) (gal) COSTPV (1994 $)a

1,000 158,000

2,200 198,000

a

 Costs were taken from EPA’s 1985 Cost Estimation Handbook (U.S.

EPA, 1985) and inflated to 1994 price levels using the MSECI.

206
(17) Annual cost of maintenance for forest land site

(other than vehicles) including monitoring, recordkeeping, etc.

SMC = [(TLAR)(16)] ENRCCI

5,445.83 where:

SMC = Annual cost of forest land site maintenance (other than vehicles), $/yr.

TLAR = Total land area required for forest

land site, ac (see Calculation #5).

16 = Annual maintenance cost, $/ac.

ENRCCI = Current Engineering News Record

Construction Cost Index at time

analysis is made. 

(18) Total base capital cost.

TBCC = COSTLAND + COSTCBT + COSTEW + 

COSTMAV

where:

TBCC = Total base capital cost of forest land

application site using onsite mobile

sludge application vehicles, $.

COSTLAND= Cost of land for forest land site, $

(see Calculation #10).

COSTCBT = Cost of clearing brush and trees, $

(see Calculation #11).

COSTEW = Cost of earthwork grading, $ (see

Calculation #12).

COSTMAV = Cost of onsite mobile sludge application vehicles, $ (see Calculation #13).

(19) Total annual operation and maintenance cost.

COSTOM = COSTLB + COSTDSL + VMC + SMC

where:

COSTOM = Total annual operation and maintenance cost for forest land application site using onsite mobile sludge

application vehicles, $/yr.

COSTLB = Annual cost of operation labor, $/yr

(see Calculation #14).

COSTDSL = Annual cost of diesel fuel, $/yr (see

Calculation #15).

VMC = Annual cost of vehicle maintenance, $/yr (see Calculation #16).

SMC = Annual cost of forest land site maintenance (other than vehicles), $/yr

(see Calculation #17).

16.4 Land Application at Reclamation Sites

16.4.1 General Information and

Assumptions Made

The cost algorithms for land application of sewage

sludge at reclamation sites presented below do not

generate the total land area required, as do the other

land application cost algorithms in this chapter, but instead generate the annual land area required. This is

because sewage sludge application for land reclamation

is usually a one-time application (i.e., sewage sludge is

not applied again to the same land area at periodic

intervals in the future), and the project must therefore

have a continuous supply of new disturbed land on

which to apply sewage sludge in future years throughout

the life of the sludge application project. 

The cost algorithms presented for land application at

reclamation sites estimate only the cost of sewage

sludge application at the site using onsite sludge application vehicles. It is assumed that the sewage sludge

is transported to the site by one of the transportation

processes discussed in Section 16.5. Typically, the onsite sludge application vehicles will obtain sludge from

a large “nurse” truck, or an interim on-site sludge storage facility. However, if the same truck is used to both

haul and apply the sludge, do not add the cost of onsite

application trucks (i.e., COSTMAV in the algorithms

would equal zero).

Disturbed or marginal lands often require extensive

grading, soil pH adjustment by lime addition, scarifying,

and vegetation seeding. Usually, the landowner pays for

the cost of these operations. However, there are provisions for including these costs in the cost algorithms, if

desired.

16.4.2 Process Design and Cost Calculations

(1) Calculate dry solids applied to land per year.

TDSS = [(SV)(8.34)(SS)(SSG)(365)]/(2,000)(100)

Same as Calculation #1 for agricultural land application

(see Section 16.2).

(2) Sludge application area required.

SDAR = (TDSS)/(DSAR)

where:

SDAR = Land area required for sludge application, ac/yr. Since sludge is typically

applied only once to reclamation

Table 16-13. Hourly Maintenance Cost for Various Capacities

of Forest Land Sludge Application Vehicles

Vehicle Capacity, (CAP) (gal) MSCTCAPa ($/hr, 1994)b

1,000 8.05

2,200 9.63

a

 MSCTCAP = Maintenance cost.

b

 Costs were taken from EPA’s 1985 Cost Estimation Handbook (U.S.

EPA, 1985) and inflated to 1994 price levels using the MSECI.

207
sites, the sludge application area required represents the annual new

land area which must be located

each year.

TDSS = Dry solids applied to land, Tons/yr

(see Calculation #1).

DSAR = Average dry solids application rate,

Tons of dry solids/ac/yr. This value

normally ranges from 10 to 100 for

typical land reclamation sites depending on sludge quality, soil conditions,

and other factors. Default value = 25

Tons/ac. (See Chapter 9.)

(3) Hourly sludge application rate.

HSV = (SV)(365)/(DPY)(HPD)

where:

HSV = Hourly sludge application rate, gal/hr.

SV = Daily sludge volume, gpd. (See Calculation #1.)

DPY = Annual sludge application period,

days/yr. This value normally ranges

from 100 to 180 days/yr for land

reclamation sites depending on climate, soil conditions, planting seasons, and other factors. Default

value = 140 days/yr.

HPD = Daily sludge application period,

hr/day. This value normally ranges

from 5 to 8 hr/day depending on

equipment used, site size, and other

factors. Default value = 8 hr/day.

(4) Capacity of onsite mobile sludge application vehicles.

Same as Calculations #4a, b, and c in Section 16.2.2 for

agricultural land application sites.

(5) Total land area required per year. 

For virtually all land reclamation sites, a larger land area is

required than that needed only for sludge application

(SDAR). The additional area may be required for buffer

zones, on-site roads, on-site storage, wasted land due to

unsuitable terrain, etc. The additional land area required

for land reclamation sites is usually not significant, since

these sites are typically located far from population centers.

TLAR = (1 + FWWAB)(SDAR)

where:

TLAR = Total land area required for land reclamation sites, ac/yr.

FWWAB = Fraction of land reclamation site

area used for purposes other than

sludge application, e.g., buffer zone,

internal roads, sludge storage, waste

land, etc. Varies significantly depending on site-specific conditions.

Default value = 0.3 for land reclamation sites.

SDAR = Site area required for sludge application, ac/yr (see Calculation #2). 

(6) Lime addition required for soil pH adjustment to a

value of pH = 6.5.

TLAPH = (FRPH)(SDAR)

where:

TLAPH = Total land area which must have

lime applied for pH control, ac/yr.

FRPH = Fraction of land reclamation site area

requiring addition of lime for adjustment of soil pH to a value of 6.5.

Typically, strip mining spoils have a

low soil pH, and substantial lime addition may be required. Default value =

1.0 for land reclamation sites.

SDAR = Site area required for sludge application, ac/yr (see Calculation #2).

(7) Earthwork required. 

Usually a potential land reclamation site will require

extensive grading to smooth out contours, provide drainage control, etc. The extent of grading required is very

site-specific, and can represent a significant portion of

the total site preparation cost when the terrain is rough.

TLARLG = (FRLG)(TLAR)

TLARMG = (FRMG)(TLAR)

TLAREG = (FREG)(TLAR)

where:

TLARLG = Total land area requiring light grading, ac/yr.

TLARMG = Total land area requiring medium

grading, ac/yr.

TLAREG = Total land area requiring extensive

grading, ac/yr.

FRLG = Fraction of land area requiring light

grading. Varies significantly depending on site-specific conditions. Default value = 0.1.

FRMG = Fraction of land area requiring medium grading. Varies significantly depending on site-specific conditions.

Default value = 0.3.

FREG = Fraction of land area requiring extensive grading. Varies significantly

depending on site-specific conditions. Typically, a land reclamation

site requires significant heavy grading. Default value = 0.6.

208
TLAR = Total land area required per year

(TLAR) (see Calculation #5).

(8) Possible number of monitoring wells needed. 

Many state regulatory agencies require that ground-water

quality monitoring wells be installed as a condition of land

reclamation site permitting. The permitting authority may

also require ground-water monitoring if he or she has

approved land application in excess of agronomic rates at

a reclamation site, as allowed by the federal Part 503

regulation. The number and depth of monitoring wells required varies as a function of site size, ground-water conditions, and regulatory agency requirements. In this

algorithm, it is assumed that even the smallest land reclamation site must have one downgradient ground-water

quality monitoring well, and one additional monitoring well

for each 200 ac/yr of total site area (TLAR) above 50 ac/yr.

In some cases, at least one upgradient well is also required.

NOMWR = 1 + [(TLAR) - 50]/200 (increase to

next highest integer)

where:

NOMWR = Number of monitoring wells required/yr.

TLAR = Total land area required per year

(see Calculation #5).

(9) Operation labor requirement.

L = 8 (NOV)(DPY)/0.7

where:

L = Operation labor requirement, hr/yr.

8 = Hr/day assumed, hr.

NOV = Number of onsite sludge application

vehicles (see Calculation #4).

DPY = Annual sludge application period,

days/yr (see Calculation #3). 

0.7 = Efficiency factor.

(10) Diesel fuel requirements for onsite mobile sludge

application vehicles.

FU = (HSV)(HPD)(DPY)(DFRCAP)/(VHRCAP)

where:

FU = Diesel fuel usage, gal/yr.

HSV = Hourly sludge application rate,

gal/hr (see Calculation #3).

HPD = Daily sludge application period,

hr/day (see Calculation #3).

DPY = Annual sludge application period,

days/yr (see Calculation #3).

DFRCAP = Diesel fuel consumption rate for certain

capacity vehicle, gal/hr, see Table 16-5.

VHRCAP = Vehicle sludge handling rate (see

Calculation #4).

(11) Annual cost of land.

COSTLAND = (TLAR)(LANDCST)

where:

COSTLAND= Annual cost of land for land reclamation site, $/yr.

TLAR = Total land area required for land

reclamation sites, ac/yr (see Calculation #5).

LANDCST = Cost of land, $/ac. Typically, the

land used for reclamation is not purchased by the municipality. Default

value = 0.

(12) Annual cost of lime addition to adjust pH of the soil.

COSTPHT = (TLAPH)(PHCST)

where:

COSTPHT = Annual cost of lime addition for pH

adjustment, $/yr.

TLAPH = Total land area which must have

lime applied for pH control, ac/yr

(see Calculation #6).

PHCST = Cost of lime addition, $/ac. Default

value = $163/ac.

(ENRCCI/5,445.83), based on 4

Tons of lime/ac (in some cases up

to 10 Tons/ac may be required for

extreme pH conditions).

(13) Annual cost of grading earthwork.

COSTEW = (TLARLG)(LGEWCST) + (TLARMG)

(MGEWCST) + (TLAREG)(EGEWCST)

where:

COSTEW = Cost of earthwork grading, $/yr.

TLARLG = Total land area requiring light grading, ac/yr (see Calculation #7).

LGEWCST = Cost of light grading earthwork,

$/ac. Default value = $1,359/ac.

(ENRCCI/5,445.83).

TLARMG = Total land area requiring medium

grading, ac/yr (see Calculation #7).

MGEWCST= Cost of medium grading earthwork,

$/ac. Default value = $2,719/ac.

(ENRCCI/5,445.83).

TLAREG = Total land area requiring extensive

grading, ac/yr (see Calculation

#7).

EGEWCST= Cost of extensive grading earthwork, $/ac. Default value =

$6,797/ac. (ENRCCI/5,445.83).

209
(14) Annual cost of monitoring wells.

COSTMW = ( NOMWR)(MWCST)

where:

COSTMW = Cost of monitoring wells, $/yr.

NOMWR = Number of monitoring wells required/yr (see Calculation #8).

MWCST = Cost of monitoring well, $/well. Default value = $6,797/well

(ENRCCI/5,445.83).

(15) Cost of onsite mobile sludge application vehicles.

COSTMAV = [(NOV)(COSTPV)] MSECI

990.8

where:

COSTMAV = Cost of onsite mobile sludge application vehicles, $.

NOV = Number of onsite sludge application

vehicles (see Calculation #4).

COSTPV = Cost/vehicle, $, obtained from

Table 16-6.

MSECI = Current Marshall and Swift Equipment Cost Index at time analysis

is made.

(16) Annual cost of operation labor.

COSTLB = (L)(COSTL)

where:

COSTLB = Annual cost of operation labor, $/yr.

L = Annual operation labor required, hr/yr.

COSTL = Cost of operational labor, $/hr. Default value = $22.97/hr.

(ENRCCI/5,445.83).

(17) Annual cost of diesel fuel.

COSTDSL = (FU)(COSTDF)

where:

COSTDSL = Annual cost of diesel fuel, $/yr.

FU = Annual diesel fuel usage, gal/yr.

COSTDF = Cost of diesel fuel, $/gal. Default

value = $1.09/gal

(ENRCCI/5,445.83).

(18) Annual cost of maintenance of onsite mobile sludge

application vehicles.

VMC =

[(HSV)(HPD)(DPY)(MCSTCAP)/(VHRCAP)] MSECI

990.8

where:

VMC = Annual cost of vehicle maintenance, $/yr.

HSV = Hourly sludge application rate,

gal/hr (see Calculation #3).

HPD = Daily sludge application period,

hr/day (see Calculation #3).

DPY = Annual sludge application period,

days/yr (see Calculation #3).

MCSTCAP = Maintenance cost, $/hr of operation; for specific capacity of vehicle

see Table 16-7.

VHRCAP = Vehicle sludge handling rate (see

Calculation #4)

MSECI = Current Marshall and Swift Equipment

Cost Index at time analysis is made.

(19) Annual cost of maintenance of land reclamation site

(other than vehicles) for monitoring, recordkeeping, etc.

SMC = [(TLAR)(16)] ENRCCI

5,445.83

where:

SMC = Annual cost of land reclamation site

maintenance (other than vehicles), $/yr.

TLAR = Total land area required, ac (see

Calculation #5).

16 = Annual maintenance cost, $/ac.

ENRCCI = Current Engineering News Record

Construction Cost Index at time

analysis is made. 

(20) Total base capital cost.

TBCC = COSTMAV

where:

TBCC = Total base capital cost of land reclamation site using onsite mobile

sludge application vehicles, $.

COSTMAV = Cost of onsite mobile sludge application vehicles, $ (see Calculation #15).

(21) Total annual operation, maintenance, land, and

earthwork cost.

COSTOM = COSTLB + COSTDSL + VMC + SMC +

COSTLAND + COSTPHT + COSTEW + COSTMW

where:

COSTOM = Total annual operation, maintenance, land, and earthwork cost for

land reclamation site using onsite mobile sludge application vehicles, $/yr.

COSTLB = Annual cost of operation labor, $/yr

(see Calculation #16).

COSTDSL = Annual cost of diesel fuel, $/yr (see

Calculation #17).

VMC = Annual cost of vehicle maintenance, $/yr (see Calculation #18).

210
SMC = Annual cost of site maintenance,

$/yr (see Calculation #19).

COSTLAND = Annual cost of land for reclamation

site, $/yr (see Calculation #11).

COSTPHT = Annual cost of lime addition for pH

adjustment,$/yr (see Calculation #12).

COSTEW = Annual cost of grading earthwork,

$/yr (see Calculation #13).

COSTMW = Annual cost of monitoring wells,

$/yr (see Calculation #14).

16.5 Transportation of Sewage Sludge

This section covers the two primary modes of sewage

sludge transport, truck hauling (for both liquid and dewatered sludge) and pipeline transport of liquid sludge.

For cost estimate information regarding rail or barge

transport of sewage sludge, see EPA’s Handbook: Estimating Sludge Management Costs (U.S. EPA, 1985).

Generally, truck hauling is more economical than railroad or pipeline when transporting sewage sludge less

than 150 miles. Diesel-equipped vehicles are an economic choice for larger trucks and trucks with high annual mileage operation. Pipelines have been successfully

used for transporting liquid sludge (i.e., usually less than

10 percent solids by weight) from very short distances

up to distances of 10 miles or more. Liquid sludge

pumping through pipelines is generally best accomplished with sludge containing 3 percent solids or less.

16.5.1 Truck Hauling of Liquid Sewage Sludge

16.5.1.1 General Information and

Assumptions Made

For the cost algorithms presented below for truck hauling of liquid sewage sludge, capital costs include purchase of specially designed tank trucks, as well as

construction of sludge loading facilities at the treatment

plant. The loading facility consists of a concrete slab and

appropriate piping and valving set at a height of 12 ft to

load the tanker from the top. Base annual O&M costs

include driver labor, operational labor, fuel, vehicle maintenance, and loading facility maintenance.

16.5.1.2 Process Design and Cost Calculations

(1) Number and capacity of sludge haul trucks.

Liquid sludge is hauled in tanker trucks with capacities

between 1,600 and 6,000 gal. The capacity of the tank

trucks utilized is a function of the volume of sludge to be

hauled per day and the round trip haul time. Special

tanker capacities available are 1,600, 2,000, 2,500,

3,000, 4,000, and 6,000 gal.

(1a) Total volume hauled per trip.

FACTOR = [SV (LT + ULT + RTHT)(365)]/(HPD)(DPY)

where:

FACTOR = Gallons hauled per trip if only one

truck were utilized.

SV = Daily sludge volume, gpd.

LT = Truck loading time at treatment

plant, hr. Default value = 0.4 hr.

ULT = Truck unloading time at application

site, hr. Default value = 1.0 hr. See

Table 16-14 for guidance.

RTHT = Round trip haul time from treatment

plant to application site, hr. If a

value is not available, this value

can be estimated using an average

mph for truck hauling, as follows:

Urban travel:

RTHT = RTHD

25 miles/hr average speed

Rural travel:

RTHT = RTHD

35 miles/hr average speed

Highway travel:

RTHT = RTHD

45 miles/hr average speed

where:

RTHD = Round trip haul distance from treatment

plant to application site, miles. If several

sludge application sites are planned

(e.g., private farm agricultural utilization),

use average distance to sites.

HPD = Work schedule for hauling, hr/day.

Default value = 7 hr/day.

DPY = Number of days/yr sludge is hauled,

days/yr. Default value = 120 days/yr.

See Table 16-15 for guidance.

Table 16-14. Typical Truck Unloading Time as a Function of

Type of Land Application Used

Type of Land Application

Typical Unloading

Time (Hr)

Agricultural 1.0

Forest land 1.5

Land reclamation 1.0

211
(1b) Number of vehicles and capacity of each truck. 

The number of vehicles is calculated using FACTOR

and Table 16-16.

If FACTOR exceeds 12,000, NTR = Factor/6,000

(Round to next highest integer.)

where:

NTR = Number of trucks required, from

Table 16-16.

(2) Number of round trips/yr.

NRT = SV (365)/CAP

where:

NRT = Number of round trips/yr.

SV = Daily sludge volume, gpd (see Calculation #1).

CAP = Capacity of tanker trucks required,

gal (see Table 16-16).

(3) Driver labor requirement.

DT = (LT + ULT + RTHT) NRT

where:

DT = Driver labor requirement, hr/yr.

LT = Truck loading time at treatment

plant, hr (see Calculation #1).

ULT = Truck unloading time at application

site, hr (see Calculation #1).

RTHT = Round trip haul time from treatment

plant to application site, hr (see Calculation #1).

NRT = Number of round trips/yr (see Calculation #2).

(4) Annual fuel requirement. 

Vehicle fuel usage is a function of truck size. Table 16-17

lists typical fuel usage values for different capacity trucks.

FU = (RTHD)(NRT)/FC

where:

FU = Annual fuel requirement, gal/yr.

RTHD = Round trip haul distance from treatment plant to application site, miles

(see Calculation #1).

NRT = Number of round trips/yr (see Calculation #2).

FC = Fuel consumption rate, mpg, see

Table 16-17.

(5) Cost of sludge tanker trucks.

TTCOST = (NTR)(COSTSTT) MSECI

990.8

where:

TTCOST = Total cost of all sludge tanker trucks, $.

NRT = Number of round trips/yr (see Calculation #2).

COSTSTT = Cost per sludge tanker truck, obtained from Table 16-18.

MSECI = Current Marshall and Swift Equipment Cost Index at time cost analysis is made.

Table 16-16. Number of Vehicles and Capacity of Each Truck

FACTOR, (gal)

Number (NTR) and Capacity (CAP)

of Tanker Trucks, (gal)a

<1,600 1 at 1,600

>1,600 but <2,500 1 at 2,500

>2,500 but <4,000 1 at 4,000

>4,000 but <8,000 2 at 4,000

>8,000 but <12,000 2 at 6,000

>12,000 All 6,000

a FACTOR = Gallons hauled per trip if only one truck is used.

 CAP = Capacity of tanker trucks required, gal.

 NTR = Number of trucks required.

Table 16-15. Typical Days Per Year of Sludge Hauling as a

Function of Types of Application Used and

Geographical Region

Type of Application

Geographical

Region

Typical Days/Yr

of Sludge Hauling

Agricultural or land

reclamation utilization

Northern U.S.

Central U.S.

Sunbelt States

100

120

140

Forest land utilization Northern U.S.

Central U.S.

Sunbelt States

160

180

200

Table 16-17. Fuel Use Capacities for Different Sized Trucks

Truck Capacity (CAP) (gal) Fuel Consumption (FC) (mpg)

1,600 8

2,500 7

4,000 6

6,000 5

Table 16-18. Cost of Tanker Truck

Tanker Capacity (CAP) (gal)

Cost of Truck

(COSTSTT) (1994 $)

1,600 79,000

2,500 106,000

4,000 132,000

6,000 158,000

212
(6) Cost of vehicle loading area facilities. 

The tanker truck loading facilities are assumed to

consist of a concrete slab, appropriate piping and

valving to a height of 12 ft to load the tanker from

the top. Cost of the loading area facilities are

assumed to be a function of sludge volume, (SV in

Calculation #1), in gal/yr. The relationship of SV to loading area facilities cost is graduated in a stepped manner.

COSTLA = (COSTLAB) ENRCCI

5,445.83

where:

COSTLA = Total capital cost of loading area

facilities, $.

COSTLAB = Base cost of loading area facilities,

$. This is a function of the annual

volume of sludge hauled, SV, in

gal/yr, and can be obtained from

Table 16-19.

ENRCCI = Current Engineering News Record

Construction Cost Index at time

cost analysis is made.

(7) Annual vehicle maintenance cost. 

Maintenance cost per vehicle mile traveled is a function

of truck capacity and initial cost of truck. The factors

listed in Table 16-20 are used to calculate vehicle maintenance costs.

VMC = (RTHD)(NRT)(MCM) MSECI

990.8

where:

VMC = Annual vehicle maintenance cost, $.

RTHD = Round trip haul distance from treatment plant to application site, miles

(see Calculation #1).

NRT = Number of round trips/yr (see Calculation #2).

MCM = Maintenance cost per mile traveled,

$/mile from Table 16-20.

MSECI = Current Marshall and Swift Equipment Cost Index at time cost analysis is made.

(8) Loading area facility annual maintenance cost. 

For the purposes of this program, it is assumed that

loading area facilities annual maintenance cost is a

function of loading area facility capital cost.

MCOSTLA = (COSTLA)(0.05)

where:

MCOSTLA = Annual maintenance cost for loading facilities, $/yr.

COSTLA = Total capital cost of loading area facilities, $ (see Calculation #6).

0.05 = Assumed annual maintenance cost

factor as a function of total loading

area facility capital cost.

(9) Annual cost of operation labor.

COSTLB = (DT)(COSTL)(1.2)

where:

COSTLB = Annual cost of operation labor, $/yr.

DT = Driver labor requirement, hr/yr (see

Calculation #3).

COSTL = Cost of labor, COSTL, $/hr. Default

value = $22.97/hr. (ENRCCI/5,445.83).

1.2 = A factor to account for additional labor required at the loading facility.

(10) Annual cost of diesel fuel.

COSTDSL = (FU)(COSTDF)

where:

COSTDSL = Annual cost of diesel fuel, $/yr.

FU = Annual fuel requirement, gal/yr (see

Calculation #4).

COSTDF = Cost of diesel fuel, $/gal. Default

value = $1.09. (ENRCCI/5,445.83).

Table 16-19. Loading Area Costs Based on Sludge Volume

Annual Volume of Sludge

Hauled (SV x 365) (gal/yr)

Base Cost of Loading Area

Facilities (COSTLAB) (1994 $)

 100,000 to 500,000 27,000

 500,000 to 1,000,000 41,000

 1,000,000 to 2,000,000 54,000

 2,000,000 to 4,000,000 68,000

 4,000,000 to 8,000,000 82,000

 8,000,000 to 12,000,000 95,000

12,000,000 to 16,000,000 109,000

16,000,000 to 20,000,000 122,000

20,000,000 and over 136,000

Table 16-20. Vehicle Maintenance Cost Factors

Truck Capacity

(CAP) (gal)

Maintenance Cost (MCM)

$/mile Traveled, (1994 $)

1,600 0.37

2,500 0.42

4,000 0.47

6,000 0.53

213
(11) Total base capital cost.

TBCC = TTCOST + COSTLA

where:

TBCC = Total base capital cost, $.

TTCOST = Total cost of all sludge tanker

trucks, $ (see Calculation #5).

COSTLA = Total capital cost of loading area facilities, $ (see Calculation #6).

(12) Annual operation and maintenance cost.

COSTOM = (VMC) + (MCOSTLA) + (COSTLB) +

(COSTDSL)

where:

COSTOM = Total annual operation and maintenance cost, $/yr. 

VMC = Annual vehicle maintenance cost, $

(see Calculation #7).

MCOSTLA = Annual maintenance cost for loading

facilities, $/yr (see Calculation #8).

COSTLB = Annual cost of operation labor, $/yr

(see Calculation #9).

COSTDSL = Annual cost of diesel fuel, $/yr (see

Calculation #10).

16.5.2 Truck Hauling of Dewatered 

Sewage Sludge

16.5.2.1 General Information and 

Assumptions Made

Capital costs in the cost algorithms presented below for

dewatered sewage sludge transport include construction of a truck loading facility designed to accommodate

the sludge volume within the operating schedule. Costs

include construction of a concrete loading slab, and

purchase of skip loaders and trucks. Annual O&M costs

include vehicle and loading facility maintenance, driver

and operational labor, and diesel fuel for vehicles.

16.5.2.2 Process Design and Cost Calculations

Same as Calculation #1 for truck hauling of liquid sewage sludge, shown in Section 16.5.1 above.

(1) Annual sludge volume hauled, cu yd/yr. 

Trucks which haul dewatered sludge are sized in terms

of yd3

 of capacity. Therefore, it is necessary to convert

gal of dewatered sludge to yd3

 of dewatered sludge.

SVCY = (SV)(365)/202

where:

SVCY = Sludge volume hauled, cu yd/yr.

SV = Daily sludge volume, gpd.

202 = Conversion factor, gal/cu yd.

(2) Number and capacity of sludge haul trucks. 

Dewatered sludge is hauled in trucks with capacities

between 7 and 36 cu yd. The capacity of the trucks

utilized is a function of the volume of sludge to be

hauled per day and the round trip hauling time. Typical

capacities available are 7, 10, 15, 25, and 36 cu yd.

(2a) Total sludge volume hauled per day.

FACTOR = SVCY(LT + ULT + RTHT)/(HPD)(DPY)

where:

FACTOR = Cu yd which would have to be hauled

per trip if only one truck were utilized.

SVCY = Sludge volume hauled, cu yd/yr

(see Calculation #1).

LT = Truck loading time at treatment

plant, hr (see Calculation #1 for liquid sludge, section 16.5.1.2).

ULT = Truck unloading time at application

site, hr (see Calculation #1 for liquid sludge, Section 16.5.1.2).

RTHT = Round trip haul time from treatment

plant to application site, hr (see Calculation #1 for liquid sludge, Section 16.5.1.2).

(2b) Capacity and number of haul vehicles. 

Capacity and number of haul vehicles are calculated

using FACTOR and Table 16-21.

Table 16-21. Capacity and Number of Haul Vehicles

FACTOR (cu yd)

Number (NTR) and Capacitya

of Trucks (CAP) (cu yd)

<7 1 at 7 

 7 to 10 1 at 10

10 to 15 1 at 15

15 to 25 1 at 25

25 to 36 1 at 36

36 to 50 2 at 25

50 to 72 2 at 36

a

 NTR = Number of trucks required.

214
If FACTOR exceeds 72, use:

NTR = FACTOR

36 (Round to next highest integer). 

CAP = 36 cu yd.

where:

NTR = Number of trucks required. Calculated from Table 16-21.

CAP = Capacity of truck required, cu yd.

(3) Number of round trips/yr.

NRT = (SVCY)/(CAP)

where:

NRT = Number of round trips/yr (round to

next highest integer).

SVCY = Annual sludge volume hauled, cu

yd/yr (see Calculation #1).

CAP = Capacity of truck, cu yd (see Calculation #2).

(4) Driver time.

Same as Calculation #3 for truck hauling of liquid sewage sludge in Section 16.5.1.2.

(5) Annual fuel requirement. 

Vehicle fuel usage is a function of truck size. Table

16-22 lists typical fuel usage values for different capacity trucks.

FU = (RTHD)(NRT)/(FC)

where:

FU = Annual fuel requirement, gal/yr.

RTHD = Round trip haul distance from

treatment plant to application site,

miles (see Calculation #1 for liquid sludge in Section 16.5.1.2).

NRT = Number of round trips/yr (see Calculation #3).

FC = Fuel consumption rate, miles/gal,

see Table 16-22.

(6) Cost of sludge haul trucks.

TCOSTTRK = (NTR)(COSTTRK) MSECI

990.8

where:

TCOSTTRK= Total cost of dewatered sludge haul

trucks, $. 

NTR = Number of trucks required (see Calculation #2).

COSTTRK = Cost per truck, obtained from Table

16-23.

MSECI = Current Marshall and Swift Equipment Cost Index at time cost analysis is made.

(7) Cost of vehicle loading facilities. 

Truck loading facilities are assumed to consist of a concrete slab, one or more skip loaders to load the trucks, and

miscellaneous improvements such as drainage, lighting,

etc. Cost of the truck loading facilities are assumed to be

a function of sludge volume in yd3

/yr (SVCY in Calculation

#1). The relationship of SVCY to loading area facilities cost

is graduated in a stepped manner and depends on the

number of loading vehicles required.

COSTLA = (COSTLAB) ENRCCI

5,445.83

where:

COSTLA = Total capital cost of loading area facilities, $.

COSTLAB = Base cost of loading area facilities, $.

This is a function of the annual volume of sludge hauled (SVCY in Calculation #1) and can be obtained from

Table 16-24.

ENRCCI = Current Engineering News Record

Construction Cost Index at time cost

analysis is made.

Table 16-22. Fuel Usage Values for Different Sized Trucks

Truck Capacity (CAP) (cu yd)

Fuel Consumption (FC)

(miles/gal)

 79

10 8

15 7

25 6

36 5

Table 16-23. Costs for Different Sized Trucks

Truck Capacity (CAP) yd3 Cost of Truck

(COSTTRK) (1994 $)

 7 86,000

10 129,000

15 172,000

25 226,000

36 282,000

215
(8) Annual vehicle maintenance cost. 

Maintenance cost per vehicle mile traveled is a function of

truck capacity and initial cost of the truck.The factors outlined in Table 16-25 are used to calculate vehicle maintenance costs.

VMC = (RTHD)(NRT)(MCM) MSECI

990.8

where:

VMC = Annual maintenance cost, $/yr.

RTHD = Round trip haul distance from treatment plant to application site, miles

(see Calculation #1 for truck hauling

of liquid sewage sludge). 

NRT = Number of round trips/yr (see Calculation

#3).

MCM = Maintenance cost/mile travelled, $/mile

from Table 16-25.

MSECI = Current Marshall and Swift Equipment

Cost Index at time cost analysis is made.

(9) Annual maintenance cost for loading area facilities. 

For the purposes of this program, it is assumed that loading

area facilities annual maintenance cost is a function of

loading area facilities capital cost.

MCOSTLA = (COSTLA)(0.05)

where:

MCOSTLA = Annual maintenance cost for loading

area facilities, $/yr.

COSTLA = Total capital cost of loading area facilities, $ (see Calculation #7).

0.05 = Assumed annual maintenance cost

factor as a function of total loading

area facilities capital cost.

(10) Annual cost of operational labor.

COSTLB = (DT)(COSTL)(1.2)

where:

COSTLB = Annual cost of operational labor, $/yr.

DT = Driver labor requirement, hr/yr (see

Calculation #3 for truck hauling of

liquid sludge, Section 16.5.1.2).

COSTL = Cost of labor, $/hr. Default value =

$22.97/hr. (ENRCCI/5,445.83).

1.2 = A factor to account for additional labor required at loading facility.

(11) Annual cost of diesel fuel.

COSTDSL = (FU)(COSTDF)

where:

COSTDSL = Annual cost of diesel fuel, $/yr.

FU = Annual fuel requirement, gal/yr (see

Calculation #5).

COSTDF = Cost of diesel fuel, $/gal. Default

value = $1.09/gal. (ENRCCI/5,445.83).

(12) Total base capital cost.

TBCC = TCOSTTRK + COSTLA

where:

TBCC = Total base capital cost, $.

TCOSTTRK = Total cost of dewatered sludge haul

trucks, $ (see Calculation #6).

COSTLA = Total capital cost of loading area facilities, $.

(13) Annual operation and maintenance cost.

COSTOM = (VMC) + (MCOSTLA) + (COSTLB) +

(COSTDSL)

where:

COSTOM = Total annual operation and maintenance cost, $/yr.

VMC = Annual vehicle maintenance cost,

$/yr (see Calculation #8).

MCOSTLA = Annual loading facility maintenance

cost, $/yr (see Calculation #9).

COSTLB = Annual cost of operation labor, $/yr

(see Calculation #10).

Table 16-24. Loading Area Costs

Annual Volume of Sludge

Hauled (SVCY) (yd3)

Base Cost of Loading Area

Facilities (COSTLAB) (1994 $)

 500 to 2,500 54,000

 2,500 to 5,000 61,000

 5,000 to 10,000 68,000

 10,000 to 20,000 109,000

 20,000 to 40,000 122,000

 40,000 to 60,000 136,000

 60,000 to 80,000 204,000

 80,000 to 100,000 251,000

100,000 and over 299,000

Table 16-25. Vehicle Maintenance Cost Factors

Truck Capacity (CAP) yd3 Maintenance Cost (MCM)

$/mile Traveled (1994 $)

 7 0.34

10 0.42

15 0.49

25 0.59

36 0.70

216
COSTDSL = Annual cost of diesel fuel, $/yr (see

Calculation #11).

16.5.3 Long-Distance Pipeline Transport of

Liquid Sewage Sludge

16.5.3.1 General Information and 

Assumptions Made

Friction losses associated with sludge pipelines have been

taken into account in the cost algorithms presented below

by applying a “K” factor to an otherwise unmodified HazenWilliams formula. This “K” factor, which is a function of both

sludge solids content and sludge type, is discussed in

more detail in Calculation #2 below. Pipelines with coated

interiors (e.g., glass or cement mortar linings) are often

used as a means of reducing friction loss. Because dried

sludge can “cake” on interior pipe walls, flushing pipelines

with clean water or treated effluent is also commonly

practiced as a means of reducing friction loss due to such

“caking.” In addition, flushing has been used as a means

for preventing sludge solids from settling and hardening in

dormant pipelines.

Cost considerations for these algorithms include: pipeline and pumping station construction costs and O&M

labor, materials, and energy requirements. Large variations in construction costs are associated with certain

route-specific variables, such as the number of river

crossings or the fraction of pipeline length requiring

excavation of rock. To obtain the best results, the user

is encouraged to obtain or plot a viable pipeline route on

a suitable scale map and input the most accurate design

parameter values possible. Cost of right-of-way acquisition is not included in these algorithms.

16.5.3.2 Process Design and Cost Calculations

(1) Pipeline diameter.

PD = 12 [SV/(63,448)(HPD)]0.5

(Round to next highest even integer.)

where:

PD = Pipeline diameter, inches.

SV = Daily sludge volume, gpd.

63,488 = Conversion factor = (3.1416/4)[(3

ft/sec)(7.48 gal/cu ft)(86,400

sec/day)/(24 hr/day)]

HPD = Hours per day of pumping, HPD, hr.

Note: Pipeline is assumed to be flowing full.

(2) Head loss due to pipeline friction.

PFL = K [(SV)/(HPD)(PD)2.63(C)(16.892)]1.852

where:

PFL = Head loss due to pipe friction, ft/ft. Is

function of pipe diameter, velocity,

and “C” value selected.

K = Coefficient to adjust for increased

head loss due to sludge solids content. No default value. Pipeline friction losses may be much higher for

transporting sewage sludge than for

transporting water, depending on

such factors as the sludge concentration (percent solids by weight) and

the type of sludge (raw primary, digested, etc.). The user is cautioned

that the K factors provided in Table

16-26 are highly simplified and may

give inaccurate results for pipeline

friction loss. An elaborate method for

design engineering calculations is

provided in U.S. EPA, 1979.

2.63 = Hazen-Williams constant.

C = Hazen-Williams friction coefficient.

Default value = 90.

16.892 = (646,000 gpd/cfs)/(24)(2.31)(12)2.63

(3) Head required due to elevation difference.

HELEV = ELEVMX - PSELEV

where:

HELEV = Head required due to elevation

difference, ft.

ELEVMX = Maximum elevation in the pipeline, ft.

PSELEV = Elevation at the start of the pipeline, ft.

Table 16-26. Factors for Various Sludge Concentrations and

Two Types of Sludge

K Factor

Solids Concentration

Percent by Weight

Digested

Sludge

Untreated 

Primary Sludge

1.0 1.05 1.20

2.0 1.10 1.60

3.0 1.25 2.10

4.0 1.45 2.70

5.0 1.65 3.40

6.0 1.85 4.30

7.0 2.10 5.70

8.0 2.60 7.20

217
(4) Total pumping head required.

H = [(PL)(PFL) + HELEV]

where:

H = Total pumping head required, ft.

PL = Pipeline length, ft.

PFL = Head loss due to pipe friction, ft/ft

(see Calculation #2). 

HELEV = Head required due to elevation

difference, ft (see Calculation #3).

(5) Number of pumping stations.

NOPS = H/HAVAIL

If the decimal ending for the MOPS resultant is greater than

or equal to 0.25, then round up to the next higher integer. If

it is less than 0.25, round down. Thus, if MOPS is 2.35, use

3 pump stations. If MOPS = 2.10, use 2 pump stations.

where:

NOPS = Number of pumping stations.

H = Total pumping head required, ft.

HAVAIL = Head available from each pumping station, ft. This is a function of the type of

pump, sludge flow rate, and whether

or not pumps are placed in series. Obtain this value from Table 16-27.

(6) Total horsepower required for pump stations.

HP = (H)(SV)(8.34)/(HPD)(60)(0.50)(33,000)

where:

HP = Total pumping horsepower required, hp.

H = Total pumping head required, ft

(see Calculation #5).

SV = Daily sludge volume, gpd (see Calculation #1).

HPD = Hours per day of pumping, HPD, hr

(see Calculation #1).

33,000 = Conversion factor, hp to ft-lb/min.

60 = Conversion factor, min/hr.

0.50 = Assumed pump efficiency.

8.34 = Density of water, lb/gal.

(7) Horsepower required per pump station.

HPS = HP/NOPS

where:

HPS = Horsepower required per pump

station, hp.

HP = Total pumping horsepower required,

hp (see Calculation #6).

NOPS = Number of pumping stations (see

Calculation #5).

(8) Electrical energy requirement.

E = [(0.0003766)(1.2)(H)/(0.5)(0.9)](SV)

(365)(8.34)/1,000

where:

E = Electrical energy, kWhr/yr.

0.0003766 = Conversion factor, kWhr/1,000

ft-lb.

8.34 = Density of water, lb/gal.

1.2 = Assumed specific gravity of sludge.

0.5 = Assumed pump efficiency.

0.9 = Assumed motor efficiency.

(9) Operation and maintenance labor requirement.

L = (NOPS)(LPS) + (PL)(0.02)

where:

L = Annual operation and maintenance

labor, hr/yr.

NOPS = Number of pumping stations (see

Calculation #5).

LPS = Annual labor per pump station, hr/yr.

This is a function of pump station horse

power, HPS, as shown in Table 16-28.

PL = Pipeline length, ft (see Calculation #4).

0.02 = Assumed maintenance hr/yr per ft

of pipeline, hr/ft.

Table 16-27. Head Available from Each Pumping Station 

Pipe Diameter (PD)

(inches)

Head Available

(HAVAIL) (ft)

4 & 6 450

8 260

10 & 12 230

14 & 16 210

18 & 20 200

Table 16-28. Annual Labor Per Pump Station

Pump Station 

Horsepower (HPS)

Annual O&M Labor

(LPS) (hr)

 25 700

 50 720

 75 780

100 820

150 840

200 870

250 910

300 940

350 980

218
(10) Cost of installed pipeline.

COSTPL = (1 + 0.7 ROCK)(1 + 0.15 DEPTH) 

PL (COSTP) ENRCCI

5445.83

where:

COSTPL = Cost of installed pipeline, $.

0.7 = Assumed fraction of pipeline length

that requires rock excavation.

ROCK = Fraction of pipeline length that requires rock excavation.

0.15 = Assumed fraction of pipeline length

that does not require rock excavation, but is greater than 6 ft deep.

DEPTH = Fraction of pipeline length that does

not involve rock excavation, but is

greater than 6 ft deep.

PL = Pipeline length, ft (see Calculation #4).

COSTP = Pipeline cost per unit length, $/ft. This

cost is obtained from Table 16-29.

ENRCCI = Current Engineering News Record

Construction Cost Index at time

analysis is made.

(11) Cost of pipeline crossings.

COSTPC = [NOH($26,000) + NODH($52,000) +

NRC($19,000) + NOSR($116,000) +

NOLR($462,000)] ENRCCI

5445.83

where:

COSTPC = Cost of pipe crossings, $.

NOH = Number of 2- or 4-lane highway

crossings. Default value = 1.

NODH = Number of divided highway crossings, NODH. Default value = 0.

NRC = Number of railroad tracks (2

rails/track) crossed. Default value = 2.

NOSR = Number of small rivers crossed. Default value = 0.

NOLR = Number of large rivers crossed. Default value = 0.

ENRCCI = Current Engineering News Record

Construction Cost Index at time

analysis is made.

(12) Cost of pump stations.

COSTPS = NOPS [$218,000 + 

$3,600 (HPS-25)] MSECI

990.8

where:

COSTPS = Construction cost of all pump stations.

NOPS = Number of pumping stations (see

Calculation #5).

HPS = Horsepower required per pump station, hp (see Calculation #7).

MSECI = Current Marshall and Swift Equipment Cost Index at time analysis is

made.

Note: If HPS is less than 25 hp, then, for this calculation,

let HPS = 25 hp.

(13) Annual cost of electrical energy.

COSTEL = (E)(COSTE)

where:

COSTEL = Total annual cost of electricity, $/yr.

E = Electrical energy requirement, kWhr/yr.

COSTE = Unit cost of electricity, $/kWhr. Default value = $0.121/kWhr

(ENRCCI/5445.83).

(14) Annual cost of operation and maintenance labor.

COSTLB = (L)(COSTL)

where:

COSTLB = Annual cost of operation and maintenance labor, $/yr.

L = Operation and maintenance labor

requirement, hr/yr.

COSTL = Unit cost of labor, $/hr. Default

value = $22.97/hr

(ENRCCI/5445.83).

(15) Cost of pumping station replacement parts and

materials.

COSTPM = NOPS (PS) MSECI

990.8

Table 16-29. Pipeline Cost

Pipeline Diameter (PD)

(inches)

Installed Cost (COSTP)

($/ft, 1994 $)a

 4 28.68

 6 30.99

 8 34.39

10 37.93

12 41.33

14 48.26

16 52.88

18 58.59

20 68.92

a

 Costs were taken from EPA’s 1985 Cost Estimation Handbook (U.S.

EPA, 1985) and inflated to 1994 price levels using the MSECI.

219
where:

COSTPM = Annual cost of pumping station replacement parts and materials, $/yr.

PS = Annual cost of parts and supplies for

a single pumping station, $/yr. This

cost is a function of pumping station

horse power as shown in Table 16-30.

MSECI = Current Marshall and Swift Equipment

Cost Index at time analysis is made.

(16) Total base capital cost.

TBCC = COSTPL + COSTPC + COSTPS

where:

TBCC = Total base capital cost, $.

COSTPL = Cost of installed pipeline, $.

COSTPC = Cost of pipeline crossings, $.

COSTPS = Cost of pump stations, $.

(17) Total annual operation and maintenance cost.

COSTOM = COSTEL + COSTLB + COSTPM

where:

COSTOM = Total annual operation and maintenance cost, $/yr.

COSTEL = Annual cost of electrical energy, $/yr.

COSTLB = Annual cost of operation and maintenance labor, $/yr.

COSTPM = Cost of pumping station replacement parts and materials, $/yr.

16.6 Example of Preliminary Cost

Estimation for Agricultural Land

Application to Cropland

The following preliminary cost estimation for land application of sewage sludge to cropland is for a midwestern

city generating a daily sludge volume of 131,894 gpd (20

dry t/day, 22 T/day).1

 The sludge has a suspended

solids concentration of 4 percent and the appropriate

application rate for growing corn at this site was determined to be 4 T/ac/yr (9 t/ha/yr).

16.6.1 Process Design and Cost Calculations

(1) Calculate dry solids applied to land per year.

TDSS = [(SV)(8.34)(SS)(SSG)(365)]/(2,000)(100)

where:

TDSS = Dry solids applied to land, Tons/yr.

SV = 131,894 gpd.

SS = 4 percent.

SSG = Calculate using the following equations:

SSG = 1/[(100 - SS)/100) + (SS)/(1.42)(100)]

SSG = 1/[(100 - 4)/100) + (4)/(1.42)(100)]

SSG = 1.01

TDSS = [(131,894)(8.34)(4)(1.01)(365)]/(2,000)(100)

TDSS = 8,126 Tons/year

(2) Sludge application area required.

SDAR = (TDSS)/(DSAR)

where:

SDAR = Farm area required for sludge application, ac.

TDSS = 8,126 Tons/yr.

DSAR = 4 Tons/ac/yr. 

SDAR = (8,126)/(4)

SDAR = 2,302 ac.

(3) Hourly sludge application rate.

HSV = (SV)(365)/(DPY)(HPD)

where:

HSV = Hourly sludge application rate, gal/hr.

SV = 131,894 gpd.

DPY = 120 days/yr from Table 16-1.

HPD = 8 hr/day. 

HSV = (131,894)(365)/(120)(8)

HSV = 50,147 gal/hr.

Table 16-30. Annual Cost of Pumping Station Parts and

Supplies

Pump Station 

Horsepower (HPS)

Annual Parts and Suppliesa

Cost (PS) ($/Yr, 1994 $)

 25 1,420

 50 1,490

 75 1,680

100 1,820

150 1,980

200 2,100

250 3,750

300 3,910

350 4,100

a

 Costs were taken from EPA’s 1985 Cost Estimation Handbook (U.S.

EPA, 1985) and inflated to 1994 price levels using the MSECI.

1

 See Appendix D for equations for converting sludge volume to dry

metric tons.

220
(4) Capacity of onsite mobile sludge application vehicles.

It is assumed that the sludge has already been transported

to the private farm land application site by a large-haul

vehicle. The onsite mobile application vehicles accept the

sludge from the transport vehicle and proceed to the

sludge application area to apply the sludge. 

(4a) Capacity and number of onsite mobile sludge application vehicles. 

The capacity and number of onsite mobile sludge application vehicles required is determined by comparing the

hourly sludge volume, (HSV), with the vehicle sludge

handling rate, (VHRCAP), as shown in Table 16-2.

Since the HSV is 50,147 gal/hr, the number of 4,000-gal

capacity vehicles required is calculated by:

NOV = HSV/6,545 (round to the next highest integer)

where:

NOV = Number of onsite sludge application

vehicles.

HSV = 50,147 gal/hr.

NOV = 50,147/6,545

NOV = 8

(4b) The average round trip onsite cycle time (CT) for

mobile sludge application vehicles with a capacity of

4,000 gal. is 33 from Table 16-3.

(4c) The VHRCAP for a single vehicle is 6,545 from

Table 16-4. 

(5) Total land area required.

TLAR = (1 + FWWAB)(SDAR)

where:

TLAR = Total land area required for agricultural land application site, ac.

FWWAB = 0.4.

SDAR = 2,032 ac.

TLAR = (1 + 0.4)(2,032)

TLAR = 2,845 ac.

(6) Lime addition required for soil pH adjustment to a

value of at least 6.5.

TLAPH = (FRPH)(SDAR)

where:

TLAPH = Total land area requiring lime addition, ac.

FRPH = 0.5.

SDAR = 2,032 ac.

TLAPH = (0.5)(2,032)

TLAPH = 1,016 ac.

(7) Total land area requiring light grading. 

TLARLG = (FRLG)(SDAR)

where:

TLARLG = Total land area requiring light

grading, ac.

FRLG = 0.3.

SDAR = 2,032 ac.

TLARLG = (0.3)(2,032)

TLARLG = 610 ac.

(8) Annual operation labor requirement.

L = 8 (NOV)(DPY)/0.7

where:

L = Annual operation labor requirement,

hr/yr.

NOV = 8

DPY = 120 days/yr.

8 = Hr/day assumed.

0.7 = Efficiency factor.

L = 8 (8)(120)/0.7

L = 10,971 hr/yr.

(9) Annual diesel fuel requirement for onsite mobile

sludge application vehicles.

FU = (HSV)(HPD)(DPY)(DFRCAP)/(VHRCAP)

where:

FU = Annual diesel fuel usage, gal/yr.

HSV = 50,147 gal/hr.

HPD = 8 hr/day.

DPY = 120 days/yr.

DFRCAP = 6 gal/hr from Table 16-5.

VHRCAP = 6,545 gal/hr.

FU = (50,147)(8)(120)(6)/(6,545)

FU = 44,132 gal/yr.

(10) Cost of land (COSTLAND) is zero because it is

assumed that the application of sewage sludge is on

privately owned farm land.

221
(11) Cost of lime addition to adjust pH of soil.

COSTPHT = (TLAPH)(COSTPHT)

where:

COSTPHT = Cost of lime addition, $.

TLAPH = 1,016 ac.

PHCST = $82/ac., this value assumes 2 Tons

of lime/ac requirement.

COSTPHT = (1,016)($82)

COSTPHT = $83,312

(12) Cost of light grading earthwork.

COSTEW = (TLARLG)(LGEWCST)

where:

COSTEW = Cost of earthwork grading, $.

TLARLG = 610 ac.

LGEWCST = $1,359/ac.

COSTEW = (610)($1,359)

COSTEW = $828,990

(13) Cost of onsite mobile sludge application vehicles. 

COSTMAV = (NOV)(COSTPV) MSECI

990.8

where:

COSTMAV = Cost of onsite mobile sludge application vehicles, $.

NOV = 8.

COSTPV = $185,000 from Table 16-6.

MSECI = Current Marshall and Swift Equipment

Cost Index at time of analysis is 990.8.

COSTMAV = (8)($185,000) 990.8

990.8

COSTMAV = $1,480,000

(14) Annual cost of operation labor.

COSTLB = (L)(COSTL)

where:

COSTLB = Annual cost of operation labor, $/yr. 

L = 10,971 hr/yr.

COSTL = Cost of operation labor, $22.97/hr.

COSTLB = (10,971)($22.97)

COSTLB = $252,004

(15) Annual cost of diesel fuel.

COSTDSL = (FU)(COSTDF)

where:

COSTDSL = Annual cost of diesel fuel, $/yr.

FU = 44,132 gal/yr.

COSTDF = Cost of diesel fuel, $1.09/gal.

COSTDSL = (44,132)($1.09)

COSTDSL = $48,104

(16) Annual cost of maintenance for onsite mobile

sludge application vehicles.

VMC = [(HSV)(HPD)(DPY)

(MCSTCAP)/(VHRCAP)] MSECI

990.8

where:

VMC = Annual cost of vehicle maintenance, $/yr.

HSV = 50,147 gal/hr.

HPD = 8 hr/day.

DPY = 120 days/yr.

MCSTCAP = $9.45/hr from Table 16-7.

VHRCAP = 6,545 gal/hr.

MSECI = Current Marshall and Swift Equipment Cost Index at time of analysis

is 990.8.

VMC = [(50,147)(8)(120)($9.45)/(6,545)] 990.8

990.8

VMC = $69,509

(17) Annual cost of maintenance for land application site

(other than vehicles) including monitoring, recordkeeping, etc.

SMC = [(TLAR)(16)] ENRCCI

5,445.83

where:

SMC = Annual cost of maintenance (other

than vehicles), $/yr.

TLAR = 2,845 ac.

16 = Annual maintenance cost, $/ac.

ENRCCI = Current Engineering News Record

Construction Cost Index at time of

analysis is 5445.83. 

SMC = [(2,845)(16)] 5,445.83

5,445.83

SMC = $45,520

222
(18) Total base capital cost.

TBCC = COSTLAND + COSTPHT + COSTEW

+ COSTMAV

where:

TBCC = Total base capital cost of agricultural

land application program using onsite

mobile sludge application vehicles, $.

COSTLAND= $0.

COSTPHT = $83,312.

COSTEW = $828,990.

COSTMAV = $1,480,000.

TBCC = $0 + $83,312 + $828,990 + $1,480,000

TBCC = $2,392,302

(19) Total annual operation and maintenance cost.

COSTOM = COSTLB + COSTDSL + VMC + SMC

where:

COSTOM = Total annual operation and maintenance cost for agricultural land

application program using onsite

mobile sludge application vehicles, $/yr.

COSTLB = $252,004/yr.

COSTDSL = $48,104/yr.

VMC = $69,509/yr.

SMC = $45,520/yr.

COSTOM = $252,004 + $48,104 + $69,509 + $45,520

COSTOM = $415,137/yr.

16.7 References

Chemical engineering. In: Marshall and Swift equipment cost index.

September 1994. 101(9).

Engineering news record. In: ENR construction cost index. September 5, 1994. p. 96.

Oil and Gas Journal. September 12, 1994. p. 109.

U.S. EPA. 1985. Handbook: Estimating sludge management costs.

EPA/625/6-85/010. Cincinnati, OH.

U.S. EPA. 1979. Process design manual for sludge treatment and

disposal. EPA/625/1-79/011. Cincinnati, OH.

223
Appendix A

Case Studies

This appendix presents four cases studies illustrating land application at agricultural, forest, and reclamation sites.

The case studies include:

• Madison Metropolitan Sewerage District (MMSD), Madison, Wisconsin. The MMSD applies approximately 20

dry tons of sewage sludge per day to private farmland. Reprinted from Document Long-Term Experience of

Biosolids Land Application Programs, Water Environment Research Foundation, 1993.

• Metro Wastewater Reclamation District (MWRD), Denver, Colorado. The MWRD produces 70 dry tons of sewage

sludge per day, which are either applied to agricultural land or composted and sold to the public. Reprinted from

Document Long-Term Experience of Biosolids Land Application Programs, Water Environment Research Foundation, 1993.

• The Municipality of Metropolitan Seattle (Metro), Seattle, Washington. Metro has applied sewage sludge to

private forest land, with 19,000 dry tons applied to date. Reprinted from The Future Direction of Municipal Sludge

(Biosolids) Management: Where We Are and Where We’re Going, Proceedings, Volume 1, Water Environment

Research Foundation, 1992.

• Venango County, Pennsylvania, Abandoned Mine Land Reclamation. Sewage sludge was applied in a single

application at a rate of 184 mg/ha.

These case studies provide valuable insights into design, operation, monitoring, public relations, and other aspects

of programs representing a range of sizes and geographical locations. It should be noted that, in some cases, these

programs will need to make minor operational changes to achieve compliance with the Part 503 regulation.

225
226
227
Figure 5-1. Storage tank and application vehicle.

Figure 5-2. Application vehicle.

228
229
230
231
232
233
Figure 5-3. Cadmium concentrations in the soil on site 22, Field 2.

Figure 5-4. Nickel concentrations in the soil on site 22, Field 2.

234
Figure 5-5. Lead concentrations in the soil on site 22, Field 2.

235
236
237
238
239
240
241
242
Figure 6-1. Biosolids tanker truck.

243
244
Figure 6-2. A field after biosolids application and incorporation.

245
246
247
248
249
Figure 6-3. Pollutant concentration trends (1983-1992).

250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
Figure 1. Approximate haul and application costs for compost, forest, and agriculture projects (by wet tons averaging 23% solids).

267
Figure 2. Field checklist for evaluation of potential Silvigrow sites.

268
Figure 3. Steps in the design and permitting of forest application sites.

269
Figure 4. Trail map of typical Silvigrow unit. Units are named for the township, range, and section in which they are located—Unit

24-08-02 is located in T24N R8E, Section 2. This particular unit comprises 98 acres.

270
Figure 5. Application log for tracking loadings to each compartment.

271
Figure 6. Field sheet for daily boundary and buffer checks by the site supervisor.

272
273
274
275
276
277
278
279
280
281
282
Appendix B

Federal Sewage Sludge Contacts

Table B-1. EPA Regional Sewage Sludge Contacts

REGION 1

Thelma Hamilton (WMT-ZIN)

JFK Federal Bldg.

One Congress St.

Boston, MA 02203

(617) 565-3569

Fax (617) 565-4940

REGION 2

Alia Roufaeal

Water Management Division

26 Federal Plaza

New York, NY 10278

(212) 264-8663

Fax (212) 264-9597

REGION 3

Ann Carkhuff (3WM55)

841 Chesnut St.

Philadelphia, PA 19107

(215) 597-9406

Fax (215) 597-3359

REGION 4

Vince Miller

Water Division

345 Courtland St., NE.

Atlanta, GA 30365

(404) 347-3012 (ext. 2953)

Fax (404) 347-1739

REGION 5

Ash Sajjad (5WQP-16J)

Water Division

77 W. Jackson Blvd.

Chicago, IL 60604-3590

(312) 886-6112

Fax (312) 886-7804

REGION 6

Stephanie Kordzi (6-WPM)

Water Management Division

1445 Ross Ave., #1200

Dallas, TX 75202-2733

(214) 665-7520

Fax (214) 655-6490

REGION 7

John Dunn

Water Management Division

726 Minnesota Ave.

Kansas City, KS 66101

(913) 551-7594

Fax (913) 551-7765

REGION 8

Bob Brobst (8WM-C)

Water Management Division

999 18th St., Suite 500

Denver, CO 80202-2405

(303) 293-1627

Fax (303) 294-1386

REGION 9

Lauren Fondahl

Permits Section

75 Hawthorne St. (W-5-2)

San Francisco, CA 94105

(415) 744-1909

Fax (415) 744-1235

REGION 10

Dick Hetherington (WD-184)

Water Management Division

1200 Sixth Ave.

Seattle, WA 98101

(206) 553-1941

Fax (206) 553-1775

283
Figure B-1. Map of U.S. EPA regions.

284
Appendix C

Permit Application Requirements

Permits that are issued to publicly owned treatment

works (POTWs) must include standards for sewage

sludge use or disposal. In addition, EPA may issue

sewage sludge permits to other “treatment works

treating domestic sewage” (TWTDS) (i.e., treatment

works that generate, change the quality of, or dispose

of sewage sludge).

The EPA’s sewage sludge permit program regulations

establish a framework for permitting sewage sludge use

or disposal. The regulations require submission of a

permit application that provides the permitting authority

with sufficient information to issue an appropriate permit.

A permit application must include information on the

treatment work’s identity, location, and regulatory status,

as well as information on the quality, quantity, and ultimate use or disposal of the sewage sludge managed at

the treatment works.

Because the sewage sludge permitting regulations were

promulgated several years before the Part 503 standards, they describe the required application information

in broad, almost generic terms. Currently, EPA is developing application forms and the Agency is planning to

revise the permit application regulations to reflect specifically the Part 503 standards and to enable permit

writers to tailor permit requirements to facilities’ specific

use or disposal practices.

The deadlines for submitting permit applications were

revised in 1993 and are as follows:

• Applicants requiring site-specific pollutant limits in

their permits (e.g., sewage sludge incinerators) and

facilities requesting site-specific limits (e.g., some

surface disposal sites) were required to submit applications by August 18, 1993.

• All other applicants with National Pollutant Discharge

Elimination System (NPDES) permits are required to

submit sewage sludge permit applications at the time

of their next NPDES permit renewals.

• So-called sewage sludge-only (non-NPDES) treatment works that are not applying for site-specific limits, and are not otherwise required to submit a full

permit application, only need to submit limited

screening information and must have done so by

February 19, 1994.

The permit application information that must be submitted depends upon the type of treatment works and which

sewage sludge management practices the treatment

works employs. Questions on permit applications should

be directed to the appropriate State and EPA Regional

Sewage Sludge Coordinators listed in Appendix B.

Sludge-Only Treatment Works

The limited screening information submitted by a sewage sludge-only treatment works typically will include

the following:

• Name of treatment works, contact person, mailing

address, phone number, and location.

• Name and address of owner and/or operator.

• An indication of whether the treatment works is

a POTW, privately owned treatment works, federally owned treatment works, blending or treatment operation, surface disposal site, or sewage

sludge incinerator.

• The amount of sewage sludge generated (and/or received from another treatment works), treated, and

used or disposed.

• Available data on pollutant concentrations in the sewage sludge.

• Treatment to reduce pathogens and vector attraction

properties of the sewage sludge.

• Identification of other facilities receiving the sewage

sludge for further processing or for use or disposal.

• Information on sites where the sewage sludge is used

or disposed.

285
Facilities Submitting Full Permit Applications

A full permit application is much more comprehensive

than the limited screening information described above

for sewage sludge-only facilities. A full permit application

typically will include the following information:

General Information

• Name of treatment works, contact person, mailing

address, phone number, and location.

• Name and address of owner and/or operator.

• An indication of whether the treatment works is a POTW,

privately owned treatment works, federally owned treatment works, blending or treatment operation, surface

disposal site, or sewage sludge incinerator.

• Whether the treatment works is a Class I sludge management facility (i.e., a pretreatment POTW or another

facility designated Class I by the permitting authority).

• The NPDES permit number (if any) and the number

and type of any relevant Federal, State, or local environmental permits or construction approvals applied

for or received.

• Whether any sewage sludge management occurs on

Native American lands.

• A topographic map showing sewage sludge management facilities and water bodies 1 mile beyond the

property boundary and drinking water wells 1/4 mile

beyond the property boundary.

• Results of hazardous waste testing for the sewage

sludge, if any.

• Data on pollutant concentrations in the sewage sludge.

Information on Generation of Sewage Sludge or

Preparation of a Material From Sewage Sludge

• The amount of sewage sludge generated.

• If sewage sludge is received from off site, the amount

received, the name and address of the offsite facility,

and any treatment the sewage sludge has received.

• Description of any treatment at the applicant’s facility

to reduce pathogens and vector attraction properties

of the sewage sludge.

• Description of any bagging and distribution activities

for the sewage sludge.

• If sewage sludge is provided to another facility for

further treatment, the amount provided, the name and

address of the receiving facility, and any treatment

occurring at the receiving facility.

Information on Land Application of Sewage

Sludge

• The amount of bulk sewage sludge applied to the land.

• The nitrogen content of bulk sewage sludge applied

to the land.

• The name and location of land application sites, and

a copy of the land application plan if all sites have

not been identified.

• The name and address of the owner and the person

who applies bulk sewage sludge to each site.

• The site type and the type of crop or other vegetation grown.

• Description of any processes at each land application

site to reduce vector attraction properties of the sewage

sludge.

• Ground-water monitoring data, if available.

• If bulk sewage sludge is subject to cumulative pollutant loading rates, information on how the necessary

tracking and notification requirements will be met.

• If bulk sewage sludge is applied to the land in a

different state, information on how the permitting

authority in the receiving state will be notified.

All permit applications must be signed and certified. The

permitting authority may request additional information

to assess sewage sludge use or disposal practices,

determine whether to issue a permit, or identify appropriate permit requirements.

286
Appendix D

Conversion Factors

Table D-1. Conversion Factors (Metric to U.S. Customary)

Metric U.S. Customary Unit

Name Abbreviation Multiplier Abbreviation Name

Centimeter(s) cm 0.3937 in inches

Cubic Meter m3 8.1071 x 10-4

35.3147

264.25

acre-ft

ft3

Mgal

acre-foot

cubic foot

million gallons

Cubic Meters Per Day m3/d 2.6417 x 10-4 Mgal/d or MGD million gallons per day

Cubic Meters Per Hectare m3/ha 1.069 x 10-4 Mgal/acre million gallons per acre

Degrees Celsius °C 1.8 (°C) + 32 °F degrees Fahrenheit

Gram(s) g 0.0022 lb pound(s)

Hectare ha 0.24711

0.004

acre

mi2 acre

square miles

Kilogram(s) kg 2.205 lb pound(s)

Kilograms Per Hectare kg/ha 0.0004 T/ac tons per acre

Kilograms Per Hectare Per Day kg/ha/d 0.893 lb/ac/d pounds per acre per day

Kilograms Per Square Centimeter kg/cm2 14.49 lb/in2 pounds per square inch

Kilometer km 0.6214 mi mile

Kilowatt kW 1.34 hp horsepower

Liter L 0.0353

0.264

ft3

gal

cubic foot

gallons

Liters Per Second L/s 0.035

22.826

15.85

0.023

ft3/s

gal/d

gal/min

Mgal/d

cubic feet per second

gallons per day

gallons per minute

million gallons per day

Metric Tonne t 1.10 T ton (short)

Metric Tonnes Per Hectare t/ha 0.446 T/ac tons per acre

Meter(s) m 3.2808 ft foot (feet)

Meters Per Second m/s 2.237 mi/h miles per hour

Micrograms Per Liter μg/L 1.0 ppb parts per billion

Milligrams Per Liter mg/L 1.0 ppm parts per million

Square Centimeter cm2 0.155 in2 square inch

Square Kilometer km2 0.386 mi2 square mile

287
Table D-2. Dry Weight Basis

288
Table D-2. (continued)

289
Table D-3. Conversion of Sludge Volume to Dry Metric Tons.

290