CEMP-C

Engineer

Pamphlet

415-1-261

Department of the Army

U.S. Army Corps of Engineers

Washington, DC 20314-1000

EP 415-1-261

15 July 1997

Construction

QUALITY ASSURANCE 

REPRESENTATIVE'S GUIDE

Distribution Restriction Statement

Approved for public release; distribution is unlimited.
CEMP-C

Pamphlet

No. 415-l-261

DEPARTMENT OF THE ARMY

U.S. Army Corps of Engineers

Washington, D.C. 20314

EP 415-1-261

15 July 1997

CONSTRUCTION

QUALITY ASSURANCE REPRESENTATIVE'S GUIDE

FOREWORD

This volume of the Quality Assurance Representative's Guide

addresses technologies which are used predominantly at hazardous,

toxic, and radioactive waste (HTRW) sites to contain or clean up

contamination. The reason for this pamphlet's existence and

continuance is to provide construction representatives, those with

quality assurance/quality control responsibilities, a reliable

checklist type reference for each phase of construction.

Quality Assurance/Quality Control (QA/QC) representatives will

find the information useful and appropriate for their roles of

assuring and controlling construction quality in accordance with the

plans and specifications. The guide will, therefore, become a

valuable reference when implementing project plans and

specifications. Their contents will also help refresh the memory of

experience, training, and good common sense. The application of

sound knowledge together with a proper sense of responsibility and

use of authority will result in meaningful decision making, a factor

considered essential for effective quality assurance/quality control.

The objective is to produce quality products for Corps' customers

worldwide.

FOR THE COMMANDER:

Colonel, Corps of Engineers

Chief of Staff
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TABLE OF CONTENTS

CHAPTER TITLE

 1 General Information for HTRW Projects

 2 Ground Water Extraction Systems

2.1 Ground Water Extraction

Wells

2.2 Ground Water Extraction 

Trenches 

 3 Landfill Covers and Liners

3.1 Landfill Covers and Liners

3.2 Waste Grading and Subgrade

Preparation

3.3 Low Permeability Clay Layer

3.4 Geosynthetic Clay Liner (GCL)

3.5 Geomembrane

3.6 Drainage Layer

3.7 Geotextile

3.8 Pipe and Appurtenances

3.9 Cover Soil Layer

3.10 Vegetative Cover Layer

 and Erosion Control

3.11 Test Fill

3.12 Geogrid

3.13 Gas Venting/Collection

3.14 Operation and Maintenance

 4 Soil-Bentonite Slurry Walls

 5 Solidification/Stabilization

 6 Soil Vapor Extraction Systems

 7 Ground Water Treatment Facilities

7.1 General Information for Ground 

Water Treatment Facilities

7.2 Pumps, Piping, Valves, and 

Tankage

7.3 Metals Precipitation

7.4 Filtration

7.5 Carbon Adsorption

7.6 Air Stripping

7.7 Ultraviolet Oxidation 

7.8 Chemical Handling and Sludge 

Management
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1-i

CHAPTER 1

GENERAL INFORMATION FOR HTRW PROJECTS

Paragraph Title Page

1-1 INTRODUCTION 1-1

1-2 RESPONSIBILITY 1-1

1-3 REFERENCES 1-1

1-4 AUTHORITY 1-4

1-5 REAL ESTATE 1-5

1-6 CHEMICAL QUALITY CONTROL AND 1-6

QUALITY ASSURANCE

1-7 HEALTH AND SAFETY REQUIREMENTS 1-8

1-8 ORDNANCE AND EXPLOSIVES 1-9

REQUIREMENTS

1-9 WORK PLANS AND 1-9

OTHER SUBMITTALS

1-10 HANDLING AND STORAGE OF 1-10

MATERIALS

1-11 PROGRESS SCHEDULES 1-10

1-12 COMMUNITY RELATIONS PLAN 1-11

1-13 PERMITS 1-11

1-14 PRECONSTRUCTION CONFERENCE 1-11

1-15 QUALITY CONTROL DAILY REPORT 1-12

1-16 QUALITY ASSURANCE DAILY REPORT 1-12

1-17 SPILL REPORTING 1-12

1-18 PHOTOGRAPHS 1-12

1-19 CLAIMS 1-13

1-20 CLOSEOUT REPORTS AND 1-13

RECORD DRAWINGS

1-21 OPERATION AND MAINTENANCE 1-13

(O&M)

1-22 WARRANTIES 1-14

1-23 ACRONYMS 1-14
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1-1

Chapter 1 GENERAL INFORMATION FOR HTRW PROJECTS

1-1. INTRODUCTION. This document is a useful supplement to

construction contract documents and provides detailed information on

what a Quality Assurance (QA) Representative should be looking for

during construction at Hazardous, Toxic and Radioactive Waste (HTRW)

sites. The information provided is based on the Corps of Engineers

guide specifications and the experience of Corps of Engineers

designers and QA Representatives who have worked on HTRW sites. As a

QA Representative, you must be thoroughly familiar with all the

provisions of the contract documents, including amendments and

submittals. These contract documents must be strictly enforced when

administering the contract. If there are significant differences

between the information provided in this document and the contract

documents, contact your supervisor for guidance or clarification.

 

1-2. RESPONSIBILITY. The primary purpose of a QA Representative is

to ensure that construction is carried out according to the plans and

specifications. There are many unique requirements on HTRW projects

which the QA Representative should be knowledgeable of, and ensure

compliance with the following: 

a. Federal, state, and local environmental laws and regulations

which pertain to the project. Multiple submittals dealing with

protection of the environment are generally required on HTRW projects;

b. Health and safety requirements for Government employees,

contractors, and the public;

c. Compliance with regulatory training requirements;

d. Manifesting of contaminated materials;

e. Requirements for chemical sampling and testing;

f. Ensuring regulatory milestones are being met. Your

supervisor should be notified of slips in the schedule so that the

appropriate regulatory authorities can be notified in writing;

g. Management of special contracts such as cost reimbursable

type contracts;

h. Monitoring of project funds due to lack of contingency

funding on DERP projects and state contribution (cost sharing) for EPA

lead projects;

i. Community relations plans; and

j. Procedures for site closeout.

1-3. REFERENCES.

Federal Regulations

-29 CFR 1926.65 - Hazardous Waste Operations and Emergency Response

-29 CFR 1910.120 - Hazardous Waste Operations and Emergency Response
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-Federal Acquisition Regulation (FAR) 52.236-13

-Public Law 96-510, the Comprehensive Environmental Response,

Compensation, and Liability Act (CERCLA) of 1980, also known as

Superfund

-Public Law 99-499, the Superfund Amendments and Reauthorization Act

(SARA)

Engineering Regulations

-ER 385-1-92 - Safety and Occupational Health Document 

Requirements for HTRW Activities

-ER 1110-1-263 - Chemical Data Quality Management for Hazardous Waste

Remedial Activities

Engineering Pamphlet

-EP 415-1-266 - Resident Engineer Management Guide

-EP 200-1-2 - Process and Procedures for RCRA Manifesting

Engineering Manuals

-EM 385-1-1 - Safety and Health Requirements Manual

-EM 200-1-1 - Validation of Analytical Chemistry Laboratories

-EM 200-1-2 - Technical Project Planning - Guidance for HTRW Data

Quality Design

-EM 200-1-3 - Requirements for the Preparation of Sampling and

Analysis Plans

-EM 1110-1-1804 - Geotechnical Investigations

-EM 1110-1-1906 - Soil Sampling

-EM 1110-1-4000 - Monitor Well Design, Installation, and Documentation

at Hazardous and/or Toxic Waste Sites

-EM 1110-1-4001 - Soil Vapor Extraction and Bioventing

Corps of Engineers Guide Specifications

-CEGS 01110 - Safety, Health and Emergency Response

-CEGS 01450 - Contractor’s Chemical Quality Control

Environmental Protection Agency References

-EPA/625/6-87/016 - Handbook-Ground Water

-EPA/600/R-93/182 - Quality Assurance and Quality Control for Waste

Containment Facilities

-EPA/625/R-93/003a - Subsurface Characterization and Monitoring

Techniques: A Desk Reference

-EPA/542/b-94/013 - Remedial Technologies Screening Matrix and

Reference Guide
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-EPA/530/SW-91/051 - Technical Guidance Document: Inspection

Techniques for the Fabrication of Geomembrane Field Seams

American Society of Testing Materials

-ASTM D 422-63(1990) - Test Method for Particle-Size Analysis of Soils

-ASTM D 698-91 - Laboratory Compaction Characteristics of Soil Using

Standard Effort (12,400 ft-lbf/ft (600 kN-m/m )) 3 3

-ASTM D 1140-92 - Test Method for Amount of Material in Soils Finer

Than the No. 200 (75-um) Sieve

-ASTM D 1556-90 - Test Method for Density and Unit Weight of Soil in

Place by the Sand-Cone Method

-ASTM D 1586-84(1992) - Test Method for Penetration Test and SplitBarrel Sampling of Soils

-ASTM D 1785-94 - Specification for Poly(Vinyl Chloride) (PVC) Plastic

Pipe, Schedules 40,80, and 120

-ASTM D 2167-94 - Test Method for Density and Unit Weight of Soil in

Place by the Rubber Balloon Method

-ASTM D 2216-90 - Test Method for Laboratory Determination of Water

(Moisture) Content of Soil and Rock

-ASTM D 2241-94 - Specification for Poly (Vinyl Chloride) (PVC)

Pressure-Rated Pipe (SDR Series)

-ASTM D 2488-93 - Description and Identification of Soils (VisualManual Procedure)

-ASTM D 2922-91 - Test Methods for Density of Soil and Soil-Aggregate

in Place by Nuclear Methods (Shallow Depths)

-ASTM D 3017-88(1993) - Test Method for Water Content of Soil and Rock

in Place by Nuclear Methods (Shallow Depths)

-ASTM D 3034-94 Specification for Type PSM Poly(Vinyl Chloride) (PVC)

Sewer Pipe and Fittings

-ASTM D 4318-93 - Test Method for Liquid Limit, Plastic Limit, and

Plasticity Index of Soils

-ASTM D 4643-93 - Test Method for Determination of Water (Moisture)

Content of Soil by the Microwave Oven Method

-ASTM D 5084-90 - Measurement of Hydraulic Conductivity of Saturated

Porous Material Using a Flexible Wall Permeameter

-ASTM D 5088-90 - Practice for Decontamination of Field Equipment Used

at Non-Radioactive Waste Sites

-ASTM D 5092-90 - Recommended Practice for Design and Installation of

Ground-Water Monitoring Wells in Aquifers

-ASTM D 5093-90 - Test Method for Field Measurement of Infiltration

Rate Using a Double-Ring Infiltrometer with a Sealed Inner Ring
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-ASTM D 5299-92 - Guide for Decommissioning of Ground Water Wells,

Vadose Zone Monitoring Devices, Boreholes, and Other Devices for

Environmental Activities

-ASTM D 5521-94 - Guide for Development of Ground-Water Monitoring

Wells is Granular Aquifers

-ASTM D 5608-94 - Practice for Decontamination of Field Equipment Used

at Low Level Radioactive Waste Sites

-ASTM D 5890-95 - Swell Index of Clay Mineral Component of

Geosynthetic Clay Liners

-ASTM D 5891-95 - Fluid Loss of Clay Component of Geosynthetic Clay

Liners

1-4. AUTHORITY. Make sure you know the extent and source of your

authority. Failure to coordinate with the customer could jeopardize

future work for the Corps of Engineers (USACE). There are several

types of projects for which the USACE does HTRW construction

oversight. The level of authority the QA Representative has varies

depending on the type of project. The following paragraphs describe

the types of projects for which the USACE has provided construction

oversight. 

a. Comprehensive Environmental Response, Compensation, and

Liability Act. In February 1982, the USACE entered into an

Interagency Agreement (IAG) with the Environmental Protection Agency

(EPA) to provide assistance in executing Public Law 96-510, the

Comprehensive Environmental Response, Compensation, and Liability Act

(CERCLA) of 1980, also known as Superfund. The Superfund legislation

was amended in 1986 by Public Law 99-499, the Superfund Amendments and

Reauthorization Act (SARA). Superfund projects are initiated by the

EPA to clean up contamination which has resulted from past site

activities. The level of oversight required on Superfund projects

depends on the type of project and what requirements are established

between the EPA and the USACE. These requirements then establish the

basis for a site-specific IAG between the EPA and the USACE. All

site-specific documents (IAG’s, Consent Orders, etc...) should be

carefully reviewed so that USACE personnel clearly understand the

extent of their authority. Superfund projects are divided into Fund

Lead projects and Enforcement Lead projects. 

(1) Fund Lead Projects. Fund Lead projects use public funds

(Superfund Trust Funds) to clean up hazardous waste sites. The USACE

has been involved with the design and construction of many of these

projects. During construction, the QA Representative will usually

have similar authority to that exercised on standard USACE projects. 

Processing of payments under the Superfund program requires that

special procedures be followed. Refer to EP 415-1-266 for specific

details.

 (2) Enforcement Lead Projects. Enforcement Lead Projects refer

to projects where a Potentially Responsible Party (PRP) (private party

or a Government agency) has accepted, through a consent decree,

responsibility for cleaning up a hazardous waste site. The EPA has

occasionally asked the USACE to do construction oversight for

Enforcement or PRP Lead Projects. On this type of project, the USACE

personnel usually only report construction deficiencies and safety

violations to the EPA and do not have the authority to direct

contractor activities. A prior agreement between USACE personnel and
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the EPA Remedial Project Manager on how to handle imminent safety

hazards should be in place for all Enforcement Lead Projects. 

b. Defense Environmental Restoration Program (DERP). DERP was

established in 1984 to evaluate and remediate contamination at

Department of Defense sites. DERP is implemented subject to, and in a

manner consistent with, CERCLA and SARA, however, environmental

restoration under this program is not limited to those activities

legally required by CERCLA. DERP projects are separated into two

categories: Installation Restoration Program (IRP) and Formerly Used

Defense Sites (FUDS). IRP work is done at active military bases while

FUDS work is performed at sites formerly used by the military where

contamination resulted from military activities. The level of

authority that a QA Representative has on DERP projects will usually

be similar to that exercised on standard USACE construction projects. 

c. Base Realignment and Closure (BRAC) Program. The BRAC

program requires closure and subsequent disposal of designated

Department of Defense installations. Environmental restoration is

required at many BRAC sites and the USACE is involved in many of these

environmental restoration projects. The level of authority that a QA

Representative has, varies from project to project and, should be

defined prior to the start of construction. 

d. Civil Works Projects. HTRW projects also exist on

properties owned, or operated and maintained by USACE-Civil Works. 

The level of authority the QA Representative has varies from project

to project and should be defined prior to the start of construction.

e. Environmental Support for Others (ESFO). The USACE, upon

request, provides environmental restoration support for other

Government agencies such as the Department of Energy, the General

Services Administration, and the Federal Aviation Administration, etc. 

The level of authority the QA Representative has varies from project

to project and should be defined prior to the start of construction.

1-5. REAL ESTATE. Land not owned by the Government is often required

for support zones, decontamination facilities or other construction

purposes. There are a number of methods for obtaining access to, and

the use of, such lands. These methods include the use of a

right-of-entry, a lease, a negotiated purchase, or a condemnation of

an interest in the property, if it is either privately owned or owned

by a non-Federal Governmental entity. A permit may be required if the

land is controlled by another Federal agency. A Real Estate Planning

Report (REPR) is typically prepared during the design phase of HTRW

projects which determines how access to such lands will be obtained. 

The Contracting Officer’s Representative (COR) should verify that

access to the construction site has been obtained prior to

advertisement of a construction project in accordance with the REPR or

other planning documents. QA Representatives should:

a. Know the boundary of Government-owned, leased or controlled

property;

b. Ensure that construction contractors do not trespass upon

property located outside the boundaries of the construction site; and

c. Notify your supervisor if access to additional property is

required to accomplish the construction of the project.
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d. On long-term projects, be aware of the termination dates of

any rights-of-entry, leases, or temporary easements and notify your

supervisor in sufficient time to allow for their extension if access

is required beyond such dates.

1-6. CHEMICAL QUALITY CONTROL AND QUALITY ASSURANCE. A unique aspect

of most HTRW projects is the additional responsibilities of both the

contractor and the QA Representative with respect to ensuring the

quality of sampling and chemical data. ER 1110-1-263, Chemical Data

Quality Management for Hazardous Waste Remedial Activities prescribes

chemical data quality management responsibilities and procedures for

chemical sampling, handling, and testing to assure analytical data

obtained is of sufficient quality to meet the intended needs of a

project. It should be noted that the latest revision of ER 1110-1-

263, promotes enhanced flexibility for QA activities for chemical data

quality management for HTRW projects. The project management team,

including technical support staff, determines the appropriate level of

compliance monitoring. This determination is made based upon the

intended use of the analytical results and the degree of confidence

needed in the quality of the results. The required level of

compliance monitoring is established using the Data Quality Objectives

(DQO) process (see EM 200-1-2) and should be summarized in the

Sampling and Analysis Plan (SAP). Compliance monitoring may consist

of a combination of activities including: validation of laboratories;

sample shipment inspections by the QA laboratory; field and/or

laboratory QC and QA sample analysis; laboratory analysis of doubleblind performance evaluation samples; validation of laboratory data

using USEPA regional or national functional guidelines; validation of

data using project-specific guidelines; and the evaluation of

laboratory data using comparisons of field sample, QC sample, and QA

sample analysis results.

a. Chemical Data Quality Management (CDQM). A specification

section which covers chemical data quality management (usually Section

01450) should exist in every set of plans and specifications for HTRW

and UST projects where environmental, process control, or waste

samples will be collected and analyzed. The document should be

reviewed as part of the Biddability, Constructibilty, Operability and

Environmental (BCOE) Review so that the QA Representative becomes

familiar with the CDQM requirements. This specification will outline

a detailed plan, and related data quality objectives, for collecting

and analyzing samples from all media. The specification will address

all chemistry testing, including field screening and definitive field

analysis using standard and modified protocols.

b. Sampling and Analysis Plan (SAP). The contractor is

required to prepare and submit a SAP for acceptance prior to

commencement of sampling activities. A SAP is comprised of a Field

Sampling Plan (FSP) and a Quality Assurance Project Plan (QAPP). 

Chemical measurements for the initial phases of the contract may be

allowed by the COR through an Interim Sampling and Analysis Plan

(ISAP) in accordance with CEGS 01450. The following paragraphs

provide definitions of the plans referenced above.

(1) SAP - A submittal comprised of the FSP and QAPP. The SAP

is used to define all aspects of the project sampling and analytical

work to be done.

(2) FSP - That portion of the SAP which defines the field

activities. It includes all requirements for sampling, field

documentation, onsite chemical analysis, sample packaging, etc.
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(3) QAPP - The portion of the SAP which defines the laboratory

analytical and chemical data reporting requirements. 

c. Chemical Data Quality Control Plan (CDQCP). The contractor

is also required to prepare and submit a CDQCP for acceptance prior to

the initiation of related site activities. The purpose of this plan,

distinct from the SAP, is to propose the chemical data quality control

(QC) system, staff, and qualifications that will be utilized to carry

out the CDQM specification.

d. HTRW Chemistry Laboratories. Each HTRW construction project

involving chemical sampling and analysis may require the utilization

of a HTRW Chemistry Laboratory for QA program support. If split

samples are to be generated for the project, support provided by the

designated QA Laboratory would include inspection of split sample

shipments, analysis of split samples, and preparation of a Chemical

Quality Assurance Report.

e. Review of contractor CDQM Submittals. Assistance in review

of contractor submittals related to CDQM are to be made available from

the designated HTRW design district, the HTRW Chemistry Laboratory

(assigned QA lab) or the HTRW CX. It is the responsibility of the

HTRW design district or the HTRW Chemistry Laboratory to arrange for

HTRW CX review support if necessary.

f. Contractor Reports. Contractor reports include Daily

Chemical Quality Control Reports and Chemical Quality Control Summary

Reports. Chemical Data Interim Reports can be utilized for long term

projects in order to aid the HTRW Chemistry Laboratories in producing

split sample comparative data for Chemical Quality Assurance Reports. 

The CDQM specification should detail requirements for the timing of

interim data reports.

g. Chemical Quality Assurance Report (CQAR). As part of the

data evaluation process, the designated QA laboratory may provide a

single or multiple CQARs to the Technical Manager. In general, this

report will provide an evaluation related to each split sample

shipment with regard to the status of sample integrity (i.e.,

appropriate sample packaging and preservation) as well as an

evaluation of internal QC for the contractor’s data set and the

comparison of referee sample and primary sample data. Data

discrepancies will be noted in the report which will aid the QA

Representative in making judgements relative to measurement and

payment or potential resampling. When required, the CQAR should be

made available within a maximum of 30 days of the contractor’s data

being reported to the QA Laboratory. 

h. Laboratory Validation. Laboratories providing sample

analyses utilizing standard environmental analytical methods should be

validated by CEMRO-HX-C in accordance with EM 200-1-1. For

laboratories which have never been validated for USACE HTRW projects,

12 to 16 weeks should be allowed for this process to be completed.

i. Guidance. The basic requirements for the USACE CDQM program

are detailed in ER 1110-1-263, Chemical Data Quality Management for

Hazardous, Toxic, and Radioactive Waste Remedial Activities. Related

USACE guidance includes, EM 200-1-1, Validation of Analytical

Chemistry Laboratories, EM 200-1-2, Technical Project Planning -

Guidance for HTRW Data Quality Design, EM 200-1-3, Requirements for

the Preparation of Sampling and Analysis Plans, and Corps of 

Engineers Guide Specification 01450, Chemical Data Quality Control.
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1-7. HEALTH AND SAFETY REQUIREMENTS.

 a. General. A specification section which covers safety,

health, and emergency response (usually Section 01110 from CEGS 01110

- “Safety Health & Emergency Response (HTRW/UST)”) should exist in

every set of plans and specifications for HTRW and underground storage

tank (UST) projects. This section should be reviewed as part of the

Biddability, Constructibility, Operability, and Environmental (BCOE)

Review so that the QA Representative becomes familiar with the health

and safety requirements. The specification should identify minimum

initial health and safety requirements (for personal protective

equipment (PPE), training, decontamination, air monitoring, etc.)

that the contractor must address in the Site Safety and Health Plan

(SSHP).

b. Pre-Bid Site Inspections/Visits. All prospective bidders

entering contaminated areas of the site, or who will handle samples,

soil/core borings, etc. should develop their own abbreviated SSHP for

the site inspection activities. Any site visits by prospective

bidders into contaminated areas should require the following (Refer to

EP 415-1-266, Section 3, for more details):

(1) Compliance with the abbreviated SSHP for the site visit;

(2) Presentation of minimum documentation of compliance with

training and medical surveillance requirements of OSHA, 29 CFR

1910.120/ 29 CFR 1926.65; and

(3) Signing of a "hold-harmless"-type liability waiver

statement (consult District Counsel for wording).

(4) Site visit announcements should specify if prospective

bidders must provide their own appropriate PPE in accordance with

their abbreviated SSHP. Disposable PPE may be the most appropriate,

if an accessible means of collecting and disposing of the PPE is in

place at the site. Otherwise, some form of decontamination facility

is required.

c. Notice-To-Proceed. Frequently, a phased Notice-To-Proceed,

(NTP),is issued where the contractor may work on submittals or perform

non-intrusive site activities in the support zone or clean areas of

the site pending acceptance of the SSHP and approval of the CDQCP and

SAP.

d. Site Safety and Health Plan (SSHP). The contractor is

required to prepare and submit a SSHP for acceptance prior to

commencement of on-site activities. A SSHP is the contractor’s sitespecific plan to comply with OSHA Standard 29 CFR 1926.65 - 

“Hazardous Waste Operations and Emergency Response” (the OSHA

construction standard version of 29 CFR 1910.120). Specific HTRW

requirements are identified in EM 385-1-1 - “Safety and Health

Requirements Manual” and ER 385-1-92 - “Safety and Occupational 

Health Document Requirements for HTRW Activities.” CEGS 01110 and ER

385-1-92 specify that the Federal Acquisition Regulation (FAR) 

52.236-13 for a separate Accident Prevention Plan (APP) shall be

considered met if the contractor integrates the components of the 

APP, including activity hazard analyses, into the SSHP submission. 

ER 385-1-92 requires the field office to utilize the industrial

hygiene/safety professionals in their geographic district’s Safety 

and Occupational Health Office (SOHO) to review and recommend

acceptance of the contractor’s SSHP to the COR. Acceptance of the

SSHP by the COR is usually given to the contractor by official 
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letter, and is subject to satisfactory implementation by the

contractor. While it is the Government’s responsibility to monitor

implementation of the SSHP, including activity hazard analyses,

acceptance of the SSHP by signing or initialing the documents should

not be performed. The SSHP is the contractor’s plan, and the

contractor retains the responsibility for its content and

implementation at the site. 

e. Site Safety and Health Plan Modifications. Once the SSHP is

accepted, it becomes an enforceable contract document. The SSHP can

be modified by the prime contractor's Site Safety and Health Officer

(SSHO) and the certified industrial hygienist (CIH), with concurrence

of the QA Representative, at any time. If there are questions on any

modifications, the QA Representative should consult with the

geographic district Safety and Occupational Health Office (SOHO)

and/or the design district to receive recommendations for concurrence. 

f. Daily Inspections. The SSHO’s daily inspection logs should

be attached to and submitted with the Daily Quality Control Reports.

1-8. ORDNANCE AND EXPLOSIVES (OE) REQUIREMENTS. If you encounter or

suspect the presence of OE on your site, you must immediately stop the

work and request assistance and advice from your district. Personnel

involved in activities where OE may be present must receive training

on ordnance recognition and safety. Assistance from the OE Design

District and the OE Center of Expertise(CX)is mandatory to ensure safe

operations. If OE is present at the site, the following questions

should be asked:

a. Is there a site safety plan approved by the OE CX?

b. Are construction personnel with the proper training and

qualifications on site to provide QA and oversight activities? 

1-9. WORK PLANS AND OTHER SUBMITTALS. HTRW projects have many unique

submittal requirements which are in addition to those required for

non-HTRW projects. The following is a list of some of the HTRW

specific submittal requirements:

a. Plan of Operations;

b. Remedial Action Plan;

c. Closure Plan;

d. Materials Handling Plan;

e. Chemical Sampling and Testing Plans (SAP and CDQCP);

f. Manifesting and other Regulatory Compliance Procedures;

g. Spill Prevention Control and Countermeasures Plan; 

h. Dust, Vapor, and Odor Control Plan; and 

i. Storm Water Pollution Prevention Plan. 

The actual submittal list will be developed by the contractor and

USACE on ENG Form 4288-R. Submittals may or may not have the actual
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titles listed above and some subjects may be combined and others

separated. Some submittals may require review and approval from

Federal, state or local regulators as well as several offices and

laboratories within the USACE. Subsequent chapters of this document

will describe submittal requirements for specific processes and

technologies. The QA Representative should be aware of submittal

approval requirements, i.e., whether or not submittal is required by:

(1) Other districts, divisions, or laboratories within the

USACE; or 

(2) Government agencies outside of the USACE.

1-10 HANDLING AND STORAGE OF MATERIALS.

a. Materials Handling Plan (MHP). A MHP describes procedures

for the safe handling of contaminated liquids and solids. The plan

describes off-site transportation and disposal of materials,

manifesting requirements, and chain-of-custody procedures. A MHP may

also discuss imported fill materials, truck routes to be used, traffic

safety plans, and special road permits (if required). 

b. Manifesting Requirements. USACE personnel involved with onsite management and manifesting of hazardous material must complete

specialized training. USACE policy and guidance on hazardous material

manifests and shipping has been issued under the following references:

(1) EP 200-1-2, “Process and Procedures for RCRA Manifesting”. 

This document summarizes the training requirements and procedures for

manifesting hazardous materials;

(2) Construction Bulletin No. 96-9, 13 Mar 96, Subject:

Hazardous Waste Manifest Signature Policy and Procedures;

(3) CEMP-RT memorandum dated 30 April 93, Subject: Signatory

Responsibility for Hazardous Waste Manifests and Related Documents -

Policy Guidance; 

(4) EP 415-1-266 Resident Engineer Management Guide for HTRW

Projects; and

(5) PROSPECT Course - Hazardous Waste Management and

Manifesting, Course Control Number 223 and Department of

Transportation (DOT) Refresher Training and Certification, Course

Control Number 429.

c. Treatment Storage and Disposal Facility (TSDF). The plans

and specifications should provide criteria for selection and approval

of an off-site TSDF. The facility selected may require pre-approval

by the USACE and/or the EPA.

1-11. PROGRESS SCHEDULES. The following items should be considered

when reviewing the progress schedule.

a. Delays are possible due to regulatory review. Verify that

sufficient time for regulatory review has been incorporated into the

schedule.

b. Ensure that the schedule includes sample analysis turnaround
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1-11

time, especially if sample results (such as background air or water

monitoring) are required before a specific phase of work can begin.

c. Consider how the schedule will be affected if items such as

the SAP must be submitted more than once prior to approval.

1-12. COMMUNITY RELATIONS PLAN. A community relations plan is

required on all CERCLA projects. AR 200-1 Environmental Protection

and Enhancement requires a community relations plan for all IRP and

FUDS properties that have sites included or proposed for inclusion on

the National Priorities List. Typically, QA representatives will only

provide a support role to EPA and will not become the lead in

community relations activities at CERCLA Sites. However, due to their

full-time on-site presence, QA Representatives are often faced with

being the first point of contact for concerned citizens, media

representatives, etc.

a. The QA Representative should review the community relations

plan. 

b. The QA Representative should be familiar with those who are

charged with responding to citizens and media inquiries, and should

regularly consult with these people.

1-13. PERMITS. The contractor is often required by the

specifications to obtain construction permits (building and electrical

permits, etc.) for various on-site activities. For on-site activities

under CERCLA, Federal, state, and local permits are not required. 

However, the Government and its contractors must comply with the

substantive requirements of all Applicable or Relevant and Appropriate

Requirements (ARARs) (Federal, state, and local laws) identified in

the Record of Decision (ROD)/Enforcement Decision Document (EDD).

a. Do the plans and specifications identify permit requirements

and who is responsible for obtaining each?

b. Has the Government and/or contractor obtained the permits

for which each is responsible? 

c. Are there any fees or prequalification requirements.

d. Have all installation permits (digging, electrical, etc...)

been obtained.

1-14. PRECONSTRUCTION CONFERENCE.

a. Ensure appropriate USACE personnel, along with the 

installation, EPA (including the Potentially Responsible Party(s), if

applicable), state, and local officials, are invited to the

preconstruction conference. 

b. In some instances representatives from the QA laboratory,

the designated HTRW design district, and/or the HTRW CX should attend

the conference.

c. Multiple preconstruction meetings may be required due to the

complexity of some HTRW projects.
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1-12

d. The QA Representative will be responsible for assisting the

COR in setting the agenda and conducting preconstruction conferences. 

1-15. QUALITY CONTROL DAILY REPORT. Quality Control Daily Reports

are broader in scope for HTRW sites because of issues related to

health and safety, regulatory requirements, and chemical sampling and

analysis. The following are items commonly submitted in Quality

Control Daily Reports for HTRW sites:

a. Daily health and safety report;

b. Calibration data and certification of testing equipment; and

c. Qualifications of personnel performing testing and

monitoring.

If chemical sampling and analyses are included in a report, The QA

Representative should submit copies to the QA laboratory. 

1-16. QUALITY ASSURANCE DAILY REPORT. The primary focus of QA

reports is to document the QA tasks which have been performed. QA

reports are also important for supporting construction costs for

contracts which contain unit price items, and for cost-reimbursable

contracts such as Total Environmental Restoration Contracts (TERC). 

Daily reports need to be accurate to support audits and prevent double

billing.

1-17. SPILL REPORTING. There are many different environmental

regulations that require spill reporting and notification of

regulatory agencies. Since the USACE does work for many different

customers, the person or agency responsible for reporting spills may

vary depending upon the project. In all cases, USACE employees must

report spills as required by statute and regulation. Just notifying

the customer does not relieve the USACE or contractor personnel of

liability. Guidance on complying with spill reporting regulations is

provided in the Headquarters Memorandum entitled “Spill Reporting

Procedures for USACE Personnel Involved in HTRW Projects” dated 20

July 1995.

a. Are you familiar with the spill reporting requirements for

the project?

b. It is recommended that QA Representative consult with the

Office of Counsel regarding spill reporting requirements prior to

undertaking management of a project.

c. Verify the contract specifications contain a section which

outlines contractor responsibilities regarding spill reporting

requirements.

1-18. PHOTOGRAPHS. Photographs and videos are taken to document site

conditions and activities. Remotely located video cameras (including

time-lapse surveillance) are often used to allow the QA Representative

to inspect construction activities without putting on protective

equipment and physically visiting the construction site. 

a. Site conditions prior to the start of site activities should

be documented with photographs or video tapes. Aerial photographs 
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1-13

can also be valuable in documenting preconstruction site conditions. 

Make frequent checks of video cameras to ensure they are operable and

positioned correctly.

b. Photographs or videos of existing roads used as haul routes

should be taken prior to the start of construction to help document

potential damage resulting from construction traffic.

c. Photographs or videos should document each phase of

construction, equipment used, and construction techniques.

d. Dates and activities shown on photographs and videos should

be well documented.

1-19. CLAIMS. There are many opportunities for the contractor to

make claims against the Government on HTRW projects because it is

often difficult to characterize the nature and extent of contamination

during design. 

a. Differing site conditions should be immediately documented

and reported to your supervisor.

b. Time spent by contractors due to differing site conditions

or regulatory changes should be carefully documented. 

c. Determine if additional testing is required to verify

differing site conditions.

d. Actual quantities often exceed estimated quantities on HTRW

sites. Carefully document actual quantities.

1-20. CLOSEOUT REPORTS AND RECORD DRAWINGS.

a. There are additional record keeping requirements for HTRW

projects. Record drawings are required for things such as monitoring

well installation, geomembrane panel layout, and sampling locations. 

Subsequent chapters will provide more detail on requirements for

record drawings. 

b. Closeout reports are required for EPA projects. Closeout

reports are also required by most states for UST removals. 

c. States and other agencies often have requirements for

submission of record drawings, analytical data, and other information. 

1-21. OPERATION AND MAINTENANCE (O&M). Specific O&M requirements

are covered in subsequent chapters of the document. The

specifications should be reviewed to determine what permits are

required for O&M of the facility.

a. Confirm the requirements for startup, O&M, and transition of

the facility to the follow-on agency/operator are detailed in the

contract specifications. 

b. Check requirements for spare parts, replenishment of

chemicals, etc. at the time of project transfer.

c. Operating permits may take considerable effort and time to
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1-14

obtain. Have required operating permits been obtained by the

Government or contractor? 

d. Have applicable project files been transferred from the

construction contractor to the operation and maintenance

agency/contractor.

1-22. WARRANTIES. Make sure you are clear about when warranties

begin. Warranties generally begin at project acceptance and not with

completion of the O&M phase. In fact, these periods are both

typically one year in length so both would expire at the same time,

and just as the project is being transferred. Careful BCOE review and

coordination is necessary to ensure that both the O&M and warranty

provisions are acceptable to the end user of the facility.

1-23. ACRONYMS. The following is a list of acronyms used in this

document: 

Acronym Definition

APP Accident Prevention Plan

ARAR Applicable or Relevant and Appropriate 

 Requirement

ASTM American Society for Testing and Materials

BCOE Biddability, Constructibility, Operability 

 and Environmental

BRAC Base Realignment and Closure

CDQCP Chemical Data Quality Control Plan

CDQM Chemical Data Quality Management

CERCLA Comprehensive Environmental Response 

 Compensation and Liability Act

CIH Certified Industrial Hygienist

COR Contracting Officer’s Representative

CQAR Chemical Quality Assurance Report

CX Center of Expertise

DERP Defense Environmental Restoration Program 

DO Dissolved Oxygen

DOT Department of Transportation

DQO Data Quality Objectives

EDD Enforcement Decision Document

EPA Environmental Protection Agency

ESFO Environmental Support for Others

FAR Federal Acquisition Register

FSP Field Sampling Plan

FUDS Formerly Used Defense Sites

GAC Granular Activated Carbon

GCL Geosynthetic Clay Liners

HDPE High Density Polyethylene

HTRW Hazardous, Toxic and Radioactive Waste

IAG Interagency Agreement

IRP Installation Restoration Program

ISAP Interim Sampling and Analysis Plan

MHP Materials Handling Plan

O&M Operation and Maintenance

OE Ordnance and Explosives

ORP Oxidation-Reduction Potential

OSHA Occupational, Safety and Health 

 Administration

PPE Personal Protective Equipment

PVC Polyvinyl Chloride
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1-15

QA Quality Assurance

QAPP Quality Assurance Project Plan

QC Quality Control

RCRA Resource Conservation and Recovery Act

REPR Real Estate Planning Report

ROD Record of Decision

SAP Sampling Analysis Plan

SARA Superfund Amendments and Reauthorization Act

SCADA Supervision Control and Data Acquisition

SDRI Sealed Double Ring Infiltrometer

SSHO Site Safety and Health Officer

SSHP Site Safety and Health Plan

VFPE Very Flexible Polyethylene
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2.1-i

CHAPTER 2.1

GROUND WATER EXTRACTION WELLS

Paragraph Page

2.1-1 GENERAL 2.1-1

a. Scope 2.1-1

b. Equipment 2.1-1

c. Preconstruction Submittals 2.1-2

d. Construction Submittals 2.1-3

e. Start-Up Submittals 2.1-3

2.1-2 PRODUCTS 2.1-3

a. Water 2.1-3

b. Below-Ground Equipment 2.1-4

2.1-3 EXECUTION 2.1-5

a. Drilling 2.1-5

b. Installation 2.1-6

c. Predevelopment 2.1-7

d. Development 2.1-7

e. Installation of Equipment 2.1-8

f. Wells Containing Light 2.1-8

 Non-Aqueous Phase Liquids

 (LNAPL)

g. Manhole or Doghouse 2.1-8

h. Abandoning Wells 2.1-8

i. Ground Water Monitoring Wells 2.1-9
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2.1-1

CHAPTER 2.1 GROUND WATER EXTRACTION WELLS

2.1-1. GENERAL. Ground water extraction wells are often an integral

part of a pump and treat system. The extraction wells remove

contaminated ground water or create a hydrologic barrier to the

movement of a plume of contaminated ground water. Each well extracts

water at rates that can vary from a few gallons per minute up to

hundreds of gallons per minute. Other fluids, such as non-aqueous

phase liquids, may also be removed using extraction wells. The water

from an extraction well system usually is pumped to a treatment plant

where the contaminants are removed. After the water has been treated,

it may be discharged back into the subsurface, to a sewer system, or

to a lake or stream. Subsurface discharge can be accomplished by

means of one or more recharge wells. These wells are designed to

recharge ground water, to provide some measure of hydrologic control

on the migration of the contaminated ground water, or to create a

flushing of contaminants toward adjacent extraction wells.

a. Scope. This section describes the installation of ground

water extraction and recharge wells. Monitoring wells and piezometers

are also installed as part of ground water extraction systems and they

are discussed to a limited extent in this section. For the purposes

of this document, the term piezometer will refer to a device that is

used to measure the ground water elevation of a particular hydrologic

unit (geologic material that has distinct hydrologic parameters), 

whereas a monitoring well will be used to obtain a representative

water sample in addition to water elevation data. See EM-1110-1-4000,

and ASTM D 5092 for more detailed information on monitoring wells.

b. Equipment.

(1) Well Drilling Equipment.

(a) Determine that the drill rig has been inspected in

accordance with the provisions of EM-385-1-1 (Chap. 16). 

(b) Confirm that the contractor is maintaining records of tests

and inspections on site.

(c) Confirm the rig is free of fluid leaks and has been

decontaminated prior to moving onto the drilling location. ASTM

Standards D 5088 and D 5608 address decontamination of field

equipment. 

(d) Confirm that the drill rig is capable of performing the

approved drilling method. Additional guidance on drilling methods can

be found in EPA/625/6-87/016.

(e) Ensure that the driller has all of the sampling equipment

for the required geotechnical and chemical samples (split spoons,

stainless steel split spoons, shelby tubes, etc.). Additional

guidance on sampling methods can be found in EM 1110-1-1906 and

EPA/625/R-93/003a.

(f) Ensure that the rig is equipped to carry out Standard

Penetration Tests per ASTM D-1586.

(2) Personnel.
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2.1-2

(a) Ensure that the driller is licensed in the State to perform the

required work. 

(b) Confirm that all persons working in the exclusion zone meet

OSHA requirements for training and medical surveillance and that they

have read and signed the SSHP. They also must be wearing appropriate

protective clothing as described in the SSHP.

c. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Drilling and Well Installation Plan which describes:

& the drilling method and equipment;

& well installation procedures;

& soil/rock logging procedures and forms;

& soil sampling and sample handling procedures;

& drill cuttings/fluid handling plan;

& well development procedures;

& well testing procedures and equipment;

& well permitting information (copies of all permits must be

maintained on site);

& procedures to obtain digging permits/utility clearances;

and

& decontamination procedures.

The plan needs to outline the responsibilities and authorities for

each of the above activities.

(a) Verify that the drilling subcontractor has read the well

installation specifications prior to installation of the wells.

(b) Qualifications for the driller should be submitted if

licenced drillers are required in that state. Verify that the

qualifications meet the specifications and any state requirements. 

The qualifications, including education and experience, of the

geologist or engineer responsible for logging the materials

encountered in drilling should also be submitted for information. 

(2) Submittals or catalog information on:

& well screen and casing;

& cement and/or bentonite well sealant;

& precast well head vaults (if applicable);

& piping;

& pump(s) and associated equipment;
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2.1-3

& gauges and controls; and

& electrical components. 

(3) Gradation test results for filter pack material and pipe

bedding/backfill, if required.

d. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Boring logs for extraction, injection, or monitoring wells. 

(2) Proposed well locations or well screen placement may be a

submittal if well construction was left to the contractor based on

conditions encountered. Contact the design district if uncertainty

exists about the adequacy of the proposal.

(3) Well construction diagrams for each well installed.

(4) Water yield test results for individual extraction (or

recharge) wells. Water yields are determined by performing specific

capacity tests and are used to verify design assumptions. Results of

these tests may need to be submitted to the designer for review and

approval.

(5) Chemical sampling results from the initial well sampling. 

(6) Water level measurements and contour maps as required. 

This information may need to be submitted to the designer for review

and approval.

(7) Geophysical logs such as gamma, neutron, resistivity, etc.,

if required.

(8) Well development records including parameter measurements

and any required photos.

(9) Well testing records such as specific capacity tests.

(10) Well registration records with local/state authorities if

the contractor has been assigned this responsibility.

e. Start-up Submittals. The contractor should provide start-up

submittals as required by the specifications. The following is a list

of typical submittal requirements.

(1) Completed Start-Up Checklist. This checklist is used to

ensure that the equipment and controls will perform safely and as

expected. 

(2) Start-up Monitoring Plan. This plan identifies procedures

for initial start-up of the system including step-by-step procedures

for valve settings, circuit checks, energization, and monitoring.

2.1-2. PRODUCTS.

a. Water. Verify that the source of any water used in the

drilling/development process is approved in the specifications or

chemical testing has been performed to verify it is of adequate

quality. Note, use of water from sources with free chlorine may
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2.1-4

result in contamination of the well with trihalomethanes. This may be

a problem depending on the contaminants present in the ground water.

b. Below-Ground Equipment.

(1) Screen.

(a) Verify that well screen slot type, slot aperture, and

material (composition and wall thickness) are consistent with

specifications and the filter pack being used.

 (b) New well screen should be used for all wells. It should be

cleaned and wrapped at the factory. On-site, the screen should be

stored in a clean, safe location where it will not be damaged by

equipment. If the screen is not wrapped or is otherwise suspect,

require the screen to be steam cleaned and protected until

installation.

(2) Casing.

(a) Verify that well casing diameter, schedule, and material

type meet specified requirements. 

(b) Assure that joints can be made water-tight. 

(c) Well casing should be new and wrapped at the factory. Onsite, it should be stored in a clean, safe location where it will not

be damaged by other equipment.

(3) Filter Pack.

(a) Check that the grain size of the filter pack is compatible

with the formation and the slot size of the well screen is appropriate

for the filter pack gradation selected. The filter pack should also

meet all specifications for cleanliness, roundness etc. 

(b) If no filter pack gradation is given, check that the filter

pack is a uniform sand or gravel of gradation large enough to prevent

entry of the pack through the screen slots. Uniform means it has a

uniformity coefficient of 2.5 or less. The uniformity coefficient is

the sieve aperture passing 60 percent (D60) of the material divided by

the sieve aperture passing 10 percent (D10) of the material. 

(c) Determine if a sieve analysis of material from the

formation is required and ensure the test is carried out in accordance

with the specifications.

(4) Well Seal. There is a wide variety of requirements for

well seals among the various regulatory agencies. Therefore, the

inspector must review the contract documents and regulations since

each project will be different.

(a) Sodium-type bentonite must be used and should be provided

in the form required by specifications. 

(b) Pellets or granules should be used for bentonite seals. 

(c) Cement must meet specified requirements for type and must

be mixed with the appropriate amount of water. 

(d) In the absence of a specified mix, allow use of 6-8 gallons 
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2.1-5

of water to one 94-lb bag of cement. 

(e) Bentonite powder may be mixed with the cement to reduce

shrinkage. 

(f) If not specified, allow 3-5 percent mixture of bentonite in

the cement by weight. 

(g) The bentonite powder should be mixed with the water before

adding the cement to assure adequate mixing.

(5) Well vaults.

(a) Verify consistent diameters of vault penetrations with

associated casing, piping, or utility conduits. 

(b) Vault covers must be appropriate for traffic conditions if

flush-mounted. 

(c) Ensure the ground surface slopes away per specified

requirements.

(d) Assure that adequate means of opening large vault covers

are provided.

(e) Ensure proper labeling and painting of vault covers as

required by the specifications.

(f) Ensure that covers and locking mechanisms perform according

to specified requirements. 

(g) Ensure that there is proper labeling of all valves,

switches, etc.

(h) Ensure that all confined space requirements are clearly

labeled, if required.

(6) Piping.

(a) Piping must meet requirements for schedule, diameter, and

joints.

(b) Ensure that the piping is adequately supported.

2.1-3. EXECUTION.

a. Drilling.

(1) Confirm that the necessary notifications/drilling permits

have been obtained from the State, County or appropriate agency before

any drilling commences.

(2) Confirm that any required easements, leases, rights-of-way,

etc. have been obtained.

(3) Confirm that the Public Affairs Office has been notified,

when required, and that the contractor(s) know who to notify in case

of public inquiries.

(4) Check that all utility clearances have been received for

the subsurface work and that there are no overhead hazards that will 
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2.1-6

interfere with raising or lowering the drill mast.

(5) Determine that drilling locations are correct. If it is

impossible to install a well in a specified location, determine the

best alternate location that meets the requirements of the design. If

there are any questions about a possible alternate location, contact

the design district to confirm a new location. 

(6) Confirm that safe drilling procedures are used and that an

exclusion zone is well defined around the drill rig. Also verify that

required safety equipment is present and that it is calibrated and

operated in accordance with the requirements of the SSHP.

(7) If required, confirm that all drill cuttings and or liquids

are screened, drummed, labeled and stored in accordance with the work

plan. Ensure that any sampling of the drums is done in accordance

with the sampling plan. On non-CERCLA sites, a RCRA hazardous waste

determination should be made for all containerized wastes to establish

whether they may be subject to accumulation time limitations and/or

subject to special management requirements.

(8) Ensure that the field geologist records all well

installation details on the well installation diagram, especially the

volume of fluids added to the holes and the number of bags of filter

sand, cement, bentonite, etc.

(9) Verify that samples are collected at the prescribed levels

and that the geologist is logging the hole according to USACE

guidelines. Additional guidance on logging requirements can be found

in EM 1110-1-4000 and EM 1110-1-1804.

(10) Verify that the well is at the proper depth or geologic

interval before allowing the screen to be installed.

(11) Determine if slot size criteria for the screen are

outlined in the specifications. If not, the contractor will have to

perform the appropriate grain size tests and calculations should be

made to determine the appropriate screen slot size. 

(12) Determine that the diameter of the hole is within the

range stated in the specifications. 

(13) Ensure that the well location is surveyed and documented. 

Wells are typically surveyed to the nearest 1 foot horizontally and

.01 foot vertically.

 (14) Ensure that the driller has made arrangements for

emergency response and transport and that emergency numbers are posted

on site.

b. Installation.

(1) Determine that all materials to be installed in the well

are the correct diameter, length, size and grade as indicated in the

specifications. Materials should be clearly labeled and in their

original packaging or the labels should be fixed on the materials

(e.g. PVC pipe).

(2) ensure that well materials are wrapped and sterile. If

not, they must be decontaminated with a steam cleaner and wrapped to

prevent contamination. Workers handling the unwrapped screen should

wear clean (latex) gloves. The objective of not touching the screen
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2.1-7

is to minimize the possibility of biological fouling occurring in the

well.

(3) Ensure that the borehole is protected from foreign objects

or surface water run in if the borehole is left open at any time.

(4) Confirm that the well is in the center of the hole and that

centralizers are properly installed if required by the specifications. 

(5) Determine that all of the materials to be added to the

annular space are present in adequate amounts and that they meet the

requirements of the specifications.

(6) All materials to be added to the annular space (filter pack

sand, bentonite, grout, etc.) should be tremied in from bottom to top

and at a flow rate which prevents bridging. The tremie pipe should be

lowered carefully into the annulus to the bottom of the hole and the

material poured or pumped down the pipe. As the space fills the

tremie pipe should be gradually withdrawn from the hole. 

(7) Ensure that the well casing has a temporary cover on it

once it is installed to prevent foreign materials from falling into

the well.

(8) Make sure that the installers frequently measure the levels

of annular fill materials with a weighted tape. This ensures

uniformity of placement around the circumference of the annular space

and that the proper thickness of materials is maintained.

(9) After all materials are placed in the annular space, a test

should be carried out to verify the plumbness and alignment of the

wells. This requires the contractor to lower a ten foot long, steamcleaned, weighted slug of inert material (often PVC filled with sand)

the full length of the well to demonstrate the plumbness of the well

so that pumps and other equipment can be lowered into the well. 

(10) Ensure that the completed well conforms to all state/local

installation requirements. 

c. Predevelopment. After the filter pack is in place it is not

uncommon in a mud-rotary drilled hole to pump out or circulate clean

water into the hole to remove as much of the drilling mud as possible

before it "sets up" in the hole. This process needs to be fully

documented as to the amounts of fluids removed and/or added on the

well installation diagram. 

d. Development.

(1) Ensure that development does not proceed until after the

prescribed waiting period (usually 48 hours after the annulus has been

grouted).

(2) Ensure that all required instruments are in working order

before development begins and that they have been calibrated in

accordance with the requirements in the specifications. Example

instruments include pH meter, thermometer, specific conductance, total

dissolved solids (TDS), Eh or other meters which measure oxidationreduction potential, dissolved oxygen (DO) and turbidimeter.

(3) Confirm that the development proceeds until the parameters 
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2.1-8

stabilize.

(4) Confirm that the requirements for turbidity are met using a

calibrated turbidimeter.

(5) Check that the development method to be used conforms with

the method outlined in the specifications.

(6) No additives other than water should be placed in the well

unless they are specifically called for in the specifications. If

additives are to be used, ensure that the chemicals are clearly

labeled.

(7) Check any apparent digressions from the language of the

specifications with a project geologist for concurrence and document

the conversation.

e. Installation of Equipment.

(1) Ensure that the pumps that go in the hole correspond with

the specifications and submittals.

(2) Verify that the pumps are installed at the designed level

in the well.

f. Wells Containing Light Non-Aqueous Phase Liquids (LNAPL).

(1) Review the drawings to determine whether one or two pumps

are to be installed in the hole.

(2) Ensure that the installer measures the depth to water and

product in the well.

(3) Confirm that the pump(s) are installed at the depth(s)

required in the specifications. This is usually referenced to depths

above or below the water/product interface.

g. Manhole or Doghouse.

(1) Ensure that these structures comply with the plans and

specifications.

(2) Check that all equipment and piping are properly installed

and that all equipment, valves and meters are accessible and readable.

(3) Ensure that the structures have a functioning, locking

mechanism and that the required keys, etc. are provided.

(4) Manholes, etc. may be classified as confined spaces and

require appropriate safety measures outlined in the SSHP. If the

structure is a confined space, ensure that the required confined space

labeling is present.

h. Abandoning Wells. In the event that there are problems or

deficiencies with installed wells, ensure that the well is abandoned

by the contractor according to the specifications and state

regulations. This may involve grouting the hole, removing casing or

cutting it off below the ground surface, surveying (if required) and

notification of the appropriate regulatory authority. ASTM D 5299

provides additional guidance on abandoning wells.
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2.1-9

i. Ground Water Monitoring Wells. Monitoring wells follow the

same general principles for installation as outlined for extraction

wells. Requirements for the installation of monitoring wells are

addressed in EM 1110-1-4000 and ASTM D-5092. Whereas the primary

goal of an extraction well is to produce a specified pumping rate for

ground water, the goal of a monitoring well is to produce a

representative sample of ground water from the aquifer. Monitoring

wells differ from extraction wells in three main aspects: diameter,

development criteria, and surface completion.

(1) Installation.

(a) Confirm the well materials are the correct size and

schedule.

(b) Generally monitoring wells are two inches in diameter. 

However, in some cases where free product is present, four inch

diameter wells may be required.

(c) Confirm whether the surface completion is flush mounted or

a nominal stickup. 

(d) Confirm that flush mounted vaults meet requirements of size

and strength for traffic loads.

(e) Confirm that the concrete pad meets specifications and

slopes away from the well.

(f) Confirm that protective bollards are installed if required

by the specifications. The bollards should not be installed in the

concrete pad.

(g) If protective locking casing is installed, assure that it

allows access to the monitoring well.

(2) Development. ASTM D 5521 provides additional guidance on

well development.

(a) Confirm that development proceeds until the specified

parameters stabilize.

(b) Confirm that requirements for turbidity are met using a

calibrated turbidimeter.

(c) Ensure that the specified amount of water is removed during

development. This may include an amount equivalent to that added (or

lost) by drillers during drilling and installation.

(d) Check that the development method to be used conforms with

the method outlined in the specifications.
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2.2-i

CHAPTER 2.2

GROUND WATER EXTRACTION TRENCHES

Paragraph Page

2.2-1 GENERAL 2.2-1

a. Equipment 2.2-1

b. Preconstruction Submittals 2.2-1

c. Construction Submittals 2.2-2

d. Start-Up Submittals 2.2-3

2.2-2 PRODUCTS 2.2-3

a. Water 2.2-3

b. Below-Ground Equipment 2.2-3

2.2-3 EXECUTION 2.2-5

a. Trenching 2.2-5

b. Installation 2.2-5

c. Development 2.2-6

d. Installation of Equipment 2.2-6

e. Trenches Containing Light 2.2-6

 Non-Aqueous Phase Liquids

 (LNAPL)

f. Manhole or Doghouse 2.2-6
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2.2-1

CHAPTER 2.2 GROUND WATER EXTRACTION TRENCHES

2.2-1. GENERAL. This section describes the installation of ground

water extraction and recharge trenches. Extraction trenches are used

to remove contaminated ground water while recharge trenches are used

to reintroduce treated ground water back into the subsurface. 

a. Equipment.

(1) Trench Excavating Equipment.

(a) Confirm that any drill rigs used have been inspected in

accordance with the provisions of EM-385-1-1 (Chap. 16). 

(b) Confirm that the contractor is maintaining records of tests

and inspections on site.

(c) Verify that the trencher/backhoe is free from leaks of

fluids and has been decontaminated prior to moving onto the project.

(d) Confirm that the trencher/backhoe is capable of achieving

the required dimensions for the excavation.

(2) Personnel.

(a) Confirm with the Site Safety and Health Officer (SSHO) that

all persons working in the exclusion zone meet OSHA requirements for

training and medical surveillance and that they have read and signed

the SSHP. They also must be wearing appropriate protective clothing

as described in the SSHP.

(b) Confirm that the contractor who installs the ground water

collection or injection trenches has the required licenses (state or

local) to perform the work. Note that in some states a trench for

extraction or recharge of ground water is classified as a well.

(c) Confirm that personnel and equipment decontamination and

collection facilities are in place and conform with the

specifications.

b. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Excavation and Installation Plan which describes:

& the trenching method and equipment;

& screen installation procedures;

& soil/rock logging procedures and forms;

& soil sampling and sample handling procedures;

& dewatering and water handling plan (if required);

& procedures to containerize, label and store 

potentially hazardous soils or liquids (if required);
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2.2-2

& decontamination procedures;

& where required, well permitting information (copies of all

permits must be maintained on site); and

& procedures to obtain digging permits/utility clearances. 

(2) Verify that the trenching subcontractor has read the 

installation specifications prior to installation of the trenches.

(3) Qualifications for the trench installation contractor

should be submitted if licences are required in that state. Note that

some states consider ground water extraction and recharge trenches to

be wells. Verify that the contractor’s qualifications meet the

specifications and any state requirements. The qualifications,

including education and experience, of the geologist or engineer

responsible for logging the materials encountered during drilling

should also be submitted for information.

(4) Catalog information on:

& pump screen or slotted pipe and casing;

& cement and/or bentonite sealant;

& precast well head vaults (if applicable);

& piping;

& pump(s) and associated equipment;

& gauges and controls;

& electrical components;

& geosynthetic materials;

& backfill materials;

& slurry materials, e.g. bentonite, bioslurry; and

& gradation test results for filter pack material and pipe

bedding/backfill (if required).

c. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Geologic logs for extraction and/or recharge trenches.

(2) Proposed trench locations or screen placement may be a

submittal if trench construction was left to the contractor based on

conditions encountered. This submittal should be provided to the

design district for review and approval.

(3) Construction diagrams for all trenches and associated wells

and piezometers. The contractor may be required to furnish these

submittals to the design district for review and approval.

(4) Water yield test results for individual extraction (or

recharge) wells. These are determined by performing a specific

capacity test and are used to verify design assumptions. The
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2.2-3

contractor may be a required to furnish this submittal to the design

district for review and approval.

(5) Backfill density test results, if required.

(6) Chemical sampling results from initial trench sampling. 

The contractor may be required to furnish this submittal to the

designer for review and approval.

(7) Water level measurements and contour maps as required.

d. Start-up Submittals. The contractor should provide start-up

submittals as required by the specifications. The following is a list

of typical submittal requirements.

(1) Completed Start-Up Checklist. This checklist is used to

ensure that the equipment and controls will perform safely and as

expected. 

(2) Start-Up Monitoring Plan. This plan identifies procedures

for initial start-up of the system including step-by-step procedures

for valve settings, circuit checks, energization, and monitoring. 

Plans for testing each trench individually in a multi-trench system

including correct valve settings and range of acceptable flow rates in

a step test should also be included. The step test consists of

starting at a low flow rate (10 to 25 percent of the design flow rate)

and stepping up in increments to the design and finally the maximum

design flow rate. For reinjection trenches, it is critical that the

test be of sufficient length to overcome the initial wetting of the

soils so that the step test is carried out on saturated soils.

2.2-2. PRODUCTS.

a. Water. Verify that the source of any water used in the

construction of the trench is approved in the specifications or

chemical testing has been performed to verify it is of adequate

quality. Note, use of water from sources with free chlorine may

result in contamination of the well with trihalomethanes.

b. Below-Ground Equipment. 

(1) Excavation.

(a) Confirm that the trench dimensions conform to the

specifications.

(b) Verify that the trench is completed at the proper depth

and/or in the appropriate geologic unit.

(c) Confirm that any material added to the bottom of the trench

is not finer-grained than the adjacent materials.

(d) Confirm that the piping/screen is placed at the correct

slopes.

(e) Determine that all safety procedures and egresses are in

place before anyone enters trenches deeper than four (4) feet.

(2) Slotted Pipe/Screen.

(a) Verify that slot type, slot aperture, diameter, and 
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2.2-4

material (composition and wall thickness) are consistent with the 

specifications. 

(b) Verify that any backfill material in the trench under the

slotted pipe is the proper gradation, thickness, slope, etc.

(c) Slotted pipe/screen should be new and stored in a clean,

safe location where it will not be damaged by equipment.

(d) Ensure that all connections are consistent with

specifications and can be made water tight. 

(e) Verify that all joints are cleaned prior to gluing.

(f) Ensure that appropriate safety procedures are followed

before any person enters sumps or other subsurface structures to

connect piping.

(3) Piping.

(a) Verify that casing schedule, diameter, joints and material

meet specifications. 

(b) Assure that joints can be made water-tight. 

(c) Casing should be new and stored in a clean, safe location

where it will not be damaged by equipment.

(d) Verify that all joints are cleaned prior to gluing. 

(e) Above-ground piping must be UV resistant.

(f) Ensure that materials which will be in contact with the

contaminants are compatible with the contaminants.

(4) Filter Backfill. 

(a) Filter backfill must meet the required gradation. 

(b) If no filter backfill gradation is given, check that the

backfill is a uniform sand or gravel large enough to prevent entry of

the pack through the screen slots.

(c) Check the specifications to see if the backfill must be

washed.

(d) Verify that geotextiles placed on top of the filter

material meet specifications for material properties and placement.

(5) Valves, Gauges and Vaults. 

(a) Assure compliance with specification. 

(b) Verify consistent diameters of vault penetrations with

associated casing, piping, or utility conduits. 

(c) Vault covers must be appropriate for traffic conditions if

flush-mounted. 

(d) Assure that adequate means of opening large vault covers is

provided. 
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2.2-5

(e) Circular vault lids are preferable to rectilinear ones

because they cannot fall into the vault and damage the system.

2.2-3. EXECUTION.

a. Trenching.

(1) Ensure that the contractor has made arrangements for

emergency response, transport, etc.

(2) Confirm that the necessary notifications/permits have been

obtained from the State, County or appropriate agency before trenching

begins.

(3) Check that all utility clearances have been received for

the subsurface work.

(4) Determine that the trench location is in accordance with

the specifications. If it is impossible to install the trench in a

specified location, determine the best alternate location that meets

the requirements of the design. If there are any questions about a

possible alternate location, contact the design district to confirm a

new location.

(5) Confirm that safe excavating procedures are used and that

an exclusion zone is well defined around the excavator. Also

determine that required safety equipment is present and that it is

operated in accordance with the requirements of the SSHP.

Ensure that the sides of the trenches are benched or sloped according

to the provisions of EM-385-1-1.

(6) If required, confirm that all excavated materials and

liquids are containerized or covered in accordance with the

specifications or approved work plan. 

(7) Verify that samples are collected at the prescribed levels

and that the geologist is logging the trench according to USACE

guidelines.

(8) Verify that the trench is at the proper depth or geologic

interval before allowing installation of the gravel pack and screen.

(9) Verify that grain size tests and calculations have been

made to determine the appropriate screen size. Otherwise verify that

the slot size of the screen is in accordance with the specifications.

(10) Determine that the dimensions of the trench are within the

range allowed in the specifications. 

(11) If unexpected debris or liquids are encountered in the

hole, stop construction and notify the appropriate personnel including

the Site Safety Officer. At some sites, potentially hazardous waste

has been encountered while excavating.

(12) Ensure that site contingency plans for spills, releases,

etc. are in place and discussed.

b. Installation.

(1) Verify that all materials to be installed in the trench are

the correct diameter, length, size and grade as indicated in the
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2.2-6

specifications. Materials should be clearly labeled in their original

packaging or the labels should be fixed on the materials (e.g. PVC

pipe).

(2) Check that screen materials are wrapped and sterile. If

not, they must be decontaminated with a steam cleaner and wrapped to

prevent contamination. Workers handling the unwrapped screen should

wear clean (latex) gloves.

(3) Confirm that the screen is in the center of the trench. 

(4) Determine that all of the backfill materials to be added

are present in adequate amounts and that they meet the requirements of

the specifications. If the backfill is stored on the ground without

a plastic liner, the material in direct contact with the ground should

not be added as backfill.

(5) Check that the grain size of the filter pack is compatible

with the slot size of the well screen and that the filter pack meets

all specifications for cleanliness, roundness etc.

c. Development. Development of trenches is much more difficult

than development of wells. The goal of trench development is to

remove fines so that they will not damage the final pumps or cause

problems in the treatment process. The process involves using a

development pump temporarily hooked into the extraction system that is

not as susceptible to damage by fines. Usually the specifications

will state a minimum number of hours of development and a minimum

pumping rate. If the water does not clear up in the prescribed time,

it will be necessary to collect a sample to determine the quantity of

sediment still present and its constituents (silt, sand, etc.). Once

this is done, discussions with the design district can determine

whether additional development will be required.

d. Installation of Equipment.

(1) Ensure that the pumps that go in the trench correspond with

the specifications.

(2) Verify that the pumps are installed at the designed level.

e. Trenches Containing Light Non-Aqueous Phase Liquids (LNAPL).

(1) Determine whether one or two pumps are to be installed in

the trench.

(2) Ensure that the installer measures the depth to water and

product in the trench.

(3) Confirm that the pump(s) are installed at the depth(s)

required in the specifications. This is usually referenced to depths

above or below the water/product interface.

f. Manhole or Doghouse.

(1) Ensure that the structures comply with the plans and

specifications.

(2) Check that all the equipment and piping are properly

installed and that all equipment, valves and meters are accessible

and readable.
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3.1-i

CHAPTER 3.1

LANDFILL COVERS AND LINERS

Paragraph Page

3.1-1 GENERAL 3.1-1

a. Purpose and Function 3.1-1

b. Regulatory Criteria 3.1-1

3.1-2 RCRA HAZARDOUS WASTE 3.1-1

 LANDFILL COVERS

3.1-3 RCRA HAZARDOUS WASTE 3.1-1

 LANDFILL LINERS

3.1-4 GENERAL INSPECTION ITEMS 3.1-2

 FOR LANDFILLS

a. Third Party Quality 3.1-2

 Assurance Inspector

b. Reports 3.1-2

c. Quality Assurance Laboratory 3.1-3

d. Quality Assurance Sample 3.1-4

 Collection

e. Borrow Source Chemical 3.1-4

 Contamination Tests

f. Interface Friction Testing 3.1-4

g. Geosynthetic Warranties 3.1-5

h. Anchor Trenches 3.1-5

i. Access Ramps 3.1-5
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3.1-1

CHAPTER 3.1 LANDFILL COVERS AND LINERS

3.1-1. GENERAL

a. Purpose and Function. This section describes the typical

configurations used for hazardous waste landfill covers and liners. 

Subsequent sections describe the QA requirements during construction

of the various components of covers and liners. The primary purpose

of a landfill is to isolate waste materials from the environment by

minimizing the infiltration of surface water, collecting leachate

generated by the waste materials, preventing human and animal contact

with the waste materials, and controlling landfill gases.

b. Regulatory Criteria. The components of a landfill cover and

liner are dependent on functional, environmental, and regulatory

factors. The Resource Conservation and Recovery Act (RCRA) provides

guidance on cover and liner configurations for both municipal solid

waste and hazardous waste landfills. The federal guidelines for

municipal solid waste landfills are found in 40 CFR Part 258. The

federal guidelines for hazardous waste landfills are found in 40 CFR

Part 264. State and local Governmental agencies also have criteria

for landfill systems and in some instances, these criteria are more

stringent than federal guidelines. 

3.1-2. RCRA HAZARDOUS WASTE LANDFILL COVERS. The components of a

typical hazardous waste landfill cover are shown below. These

components vary from site to site depending on regulatory criteria and

availability of soils with the appropriate physical characteristics. 

From top to bottom, the components of a typical hazardous waste

landfill cover are described in Table 3.1.

TABLE 3.1

COMPONENT MATERIAL TYPICALLY USED

Top Soil 150 mm (6 inches) of top soil

Select Fill 450 mm (18 inches) or more of soil

Filter Layer Geotextile

Drainage Layer Geonet or 300 mm (12 inches) of

 sand or gravel

Barrier Layer

 -Geomembrane 40-60 mil polyethylene or PVC

 -Clay 600 mm (24 inch) layer or 

geosynthetic clay liner

Gas Venting Layer 300 mm (12 inches) of sand/gravel

Foundation Layer 300 mm (12 inches) or more of soil

 to provide slopes for drainage

Waste Material

3.1-3. RCRA HAZARDOUS WASTE LANDFILL LINERS. The components of a

typical hazardous waste landfill liner are shown below. Again, these

components vary from site to site depending on the regulatory 
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3.1-2

criteria and the availability of soils with appropriate physical

characteristics. From top to bottom, the components of a typical

hazardous waste landfill liner are described in Table 3.2.

TABLE 3.2

COMPONENT MATERIAL TYPICALLY USED

Filter Layer Sand, gravel or geotextile

Leachate Collection Layer 300 mm (12 inches) of sand or

gravel

Primary Liner 60-80 mil high density polyethylene

(HDPE)

Leak Detection Layer Geonet

Secondary Liner

 -Geomembrane 60-80 mil HDPE

 -Clay 900 mm (36 inch) layer,

Hyd. Cond. < 1 X 10 cm/sec -7

Subgrade Existing or imported soil

3.1-4. GENERAL INSPECTION ITEMS FOR LANDFILLS. The following are

general inspection items which are not unique to any single component

of a landfill cover or liner.

a. Third Party Quality Assurance Inspector. A third party QA

Inspector is often hired to inspect the installation of geomembranes

and other geosynthetics. If this is the case, many of the inspection

responsibilities listed in the following chapters will be performed by

the third party QA Inspector. 

(1) Verify that the third party QA Inspector has the

appropriate qualifications as described in the plans and

specifications.

(2) Authority. If an independent third party QA Inspector will

be used, make sure the level of authority the QA Inspector has is

clearly understood by everyone. They will generally be responsible

for monitoring and documenting construction activities. However, they

will not have the authority to direct the contractor. 

b. Reports. Record keeping and reporting is a key element in

the construction of a landfill cover or liner. The following are

typical record keeping and reporting requirements during construction.

(1) Daily Reports. The purpose of daily reports is to provide

a summary of QA activities performed by the third party QA Inspectors

and to highlight matters requiring the COR’s action. The following is

an outline for a typical daily report:
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3.1-3

& project name, location, and date;

& weather conditions, including: temperature (daily high

and low); wind direction and speed; last precipitation

event; and amount of precipitation;

& construction activities underway, equipment in use, and QC

testing performed;

& summary of QA activities;

& items requiring action by the COR; and

& list of any conferences with the contractor or Government

personnel.

(2) Final Report. The last phase of landfill construction QA

involves preparing a final report by the QA inspection team. The final

report will be completed at the end of construction and typically

includes the following information:

& brief description of the project, including type of

facility, name of site, location, name of owner, design

engineer, geomembrane installer, earthwork contractor,

etc.;

& detailed description of the lining system, including

surface area, cross section, definition of all materials,

etc.;

& reference to the construction QA plan;

& copy of geosynthetic material specifications;

& copy of, or reference to, geosynthetic manufacturer’s QC

documentation;

& general record of activities, such as dates of performance

of QA operations, number and names of QA Inspectors,

number and names of geosynthetic Installer’s personnel,

etc.;

& photographic record including photographs of the site at

different phases of construction, photographs of

construction details, and photographs of QA operations;

& A copy of all forms and logs filled out by QA Inspectors

and of all their daily reports;

& copy of all field and laboratory test results;

& discussion of special problems encountered and their

solutions;

& copy of the written acceptance of the subgrade by the

geomembrane and GCL installers; and

& statement that construction has been done in substantial

accordance with the design (including modifications, if

any, approved by the design engineer).

c. Quality Assurance Laboratory. Check to see if the

specifications or QA plan require the use of an independent QA
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3.1-4

Laboratory to test geosynthtics and/or soils. 

(1) If an independent QA Laboratory is used, verify the

Laboratory's qualifications statement, including resumes of key

personnel involved in testing, conform to the requirements outlined in

the specifications. 

d. Quality Assurance Sample Collection

(1) Review the plans and specifications to determine if QA

(conformance) testing is required and on which materials. Samples

should be collected at locations approved by the QA Representative. A

QA Representative should be present during collection of these samples

to ensure they are properly packaged. 

(2) If QA testing will be performed, geosynthetic samples are

usually collected by cutting a 900 mm (3 foot) long sample for the

entire width of the roll being tested. The outside layer of

geosynthetic rolls is often removed prior to collecting QA samples. 

Samples must be properly identified with a unique sample number,

project name, sample location and date. For geosynthtics, the

manufacturer's name, product identification, lot and roll number, and

machine direction should also be identified. 

(3) Determine if the specifications contain any special

requirements for QA sample packaging.

(a) GCL samples are usually tightly rolled onto a 75 mm (3

inch) diameter core and then covered with 2 layers of plastic

sheeting. Tape should be used to hold the plastic sheeting in place.

(b) Geomembranes are generally wrapped on a cylinder and taped

in place. Geonet and geotextile samples are generally placed in a box

for safe shipment.

(4) Verify test results from the QA laboratory meet the

requirements stated in the specifications.

e. Borrow Source Chemical Contamination Tests. All borrow

soils are generally tested prior to use to verify they are not

contaminated. The plans and specifications should indicate the

frequency of testing and what testing should be performed to verify

borrow soils are clean. Contact the designer if this information is

not provided.

f. Interface Friction Testing. The interface frictional

resistance of geosynthetics is often low. Since landfill covers and

liners generally have steep slopes, this creates potential stability

problems. To ensure a landfill cover or liner will not slip, the

contractor is often required to perform direct shear tests on the

geosynthetic interfaces. 

(1) Verify friction test results indicate adequate interface

shear strength exists at the geosynthetic interfaces. Minimum

interface shear strength requirements should be outlined in the plans

and specifications. Contact the designer if they are not. 

(2) Check to see that all interface shear strength tests are

performed using the specified normal stresses, strain rates, moisture

conditions, and other test requirements outlined in the

specifications.
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3.1-5

(3) Verify the same geosynthetics and borrow sources used for

interface friction testing will be used for full scale construction.

g. Geosynthetics Warranties. Designers or regulators often

require warranties for geosynthetics. The length requirements for

warranties vary significantly from project to project. Warranties are

often required from both the geosynthetics manufacturer and the

geosynthetics installer.

(1) Review the plans and specifications to determine which

geosynthetics have warranty requirements. Become familiar with these

warranty requirements. 

(2) Discuss warranty requirements with the designer prior to

the start of construction if the requirements are not clear. 

(3) Review the warranty submittals to verify if they comply

with the warranty requirements. 

h. Anchor Trenches. Geosynthetics used to line waste

facilities terminate in an anchor trench located around the perimeter

of the liner system. Anchor trenches are typically U or V shaped. U

shaped trenches are generally a minimum of 450 mm (18 inches) deep and

300 mm (12 inches) wide. Verify the anchor trench is constructed to

the correct dimensions.

(1) Check the plans and specifications to determine the

termination point of each geosynthetic layer.

(2) Double liner systems will generally have separate anchor

trenches for primary and secondary liner systems. Verify the anchor

trenches are correctly located.

(3) Ensure that the corners of anchor trenches are slightly

rounded to avoid sharp bends in the geosynthetics. 

(4) Verify loose soil is removed from the bottom of the anchor

trench prior to placement of the geosynthetics.

(5) Require the anchor trench to be dewatered (pumped out) if

ponded water is present in the bottom of the trench.

(6) Backfilling of the anchor trench should be accomplished

with approved backfill soils placed at the required moisture content

and compacted to the required density. Carefully inspect compaction

work within the anchor trench because equipment used to compact the

soil can easily damage the geosynthetics.

i. Access Ramps. Heavily loaded vehicles must enter landfill

liners during construction activities and during placement of solid

waste. Access ramps for large landfills will be up to 5.5 m (18 ft)

in width and have grades of up to 12 percent. Large landfills will

incorporate an access ramp into the layout of the liner. Access to

small landfill liners with short side slopes will generally be

accomplished by simply placing a thick layer of soil over the liner at

the access point.

(1) Strictly enforce any requirements concerning vehicle speeds

and number of vehicles on access ramps.

(2) Construction equipment should not be allowed to brake

sharply while on the ramp.
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3.1-6

(3) Regularly inspect the access ramp for cracks and slippage

of protective soils layers. 

(4) Also inspect the protective soil layers to ensure that

thinning of this layer is not occurring due to traffic or erosion. 

Typically, these protective layers should be a minimum of 900 mm (3

feet) in thickness.
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3.2-i

CHAPTER 3.2

WASTE GRADING AND SUBGRADE PREPARATION

Paragraph Page

3.2-1 GENERAL 3.2-1

a. Preconstruction 3.2-1

 Submittals

b. Daily Reports 3.2-1

c. Manifests 3.2-1

3.2-2 EXECUTION 3.2-1

a. Clearing and Grubbing 3.2-1

b. Waste Grading 3.2-2

c. Compaction of Waste 3.2-2

d. Subgrade 3.2-3
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3.2-1

CHAPTER 3.2

WASTE GRADING AND SUBGRADE PREPARATION

3.2-1. GENERAL. The purpose of the subgrade for landfill liners and

covers is to provide a firm foundation and to establish slopes for

drainage. When landfill covers are constructed over hazardous waste

sites, waste regrading is commonly performed to flatten slopes and

minimize the amount of borrow that needs to be brought on-site. When

landfill liners are constructed, waste must be carefully placed so the

liner system is not damaged. Regraded waste and waste placed in

landfill liners usually must be compacted to minimize the amount of

settlement which occurs.

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

 A waste regrading plan which describes how waste will be

regraded and procedures which will be followed if buried drums or

other hazardous materials are discovered during regrading. Hazardous

materials anticipated to be encountered should be addressed in the

SSHP.

b. Daily Reports. Daily reports should indicate when

unexpected drums or other potentially hazardous materials are

encountered during construction.

c. Manifests. Manifesting and disposal records must be

submitted for any hazardous materials which are disposed of off site. 

Engineering Pamphlet 200-1-2 - Process and Procedures for RCRA

Manifesting provides guidance on the procedures and responsibilities

associated with manifesting hazardous waste under RCRA and Department

of Transportation regulations. 

3.2-2. EXECUTION.

a. Clearing and Grubbing. Clearing of vegetation is performed

on the surface of old landfills prior to placement of a landfill

cover. However, grubbing is generally not performed to minimize

disturbance of the waste.

(1) Limits of clearing and grubbing should be clearly

established prior to construction. 

(2) Ensure the specifications clearly define which materials

generated from clearing, grubbing, and tree removal are contaminated

and which materials are not contaminated.

(3) Ensure the contractor stockpiles contaminated cleared and

grubbed material in a location which is separated from uncontaminated

material.

(4) Ensure the contractor is disposing of both contaminated and

non-contaminated cleared and grubbed material in accordance with the

specifications.
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3.2-2

(5) Ensure stockpiles containing contaminated material are

lined and/or covered at all times in accordance with the plans and

specifications. Contact the designer if the plans and specifications

do not discuss requirements for stockpile liners and/or covers.

b. Waste Grading. 

(1) Verify waste material is placed so that large void spaces

do not exist. 

(2) Do not allow large pieces of debris (greater than 300 mm

(12 inches) in diameter) to be placed in the upper .6 meters (2 feet)

of fill. Large debris should be well dispersed in lower portions of

the waste fill. 

(3) Over excavation may be required to remove large objects

present at the surface of regraded waste.

(4) Ensure that regraded waste is placed in lifts and compacted

with a landfill compactor as described in the specifications. 

Periodically check that the lift thickness used by the contractor does

not exceed specified requirements.

(5) Halt construction in the area and notify the designers if

unexpected hazardous materials (barrels, tanks, medical waste, UXO,

etc...) are discovered during waste regrading.

(6) Ensure the contractor minimizes the amount of waste exposed

during regrading operations to reduce odor problems. 

(7) Air quality monitoring equipment should be closely

monitored during waste regrading. Daily cover may need to be placed

over areas of exposed waste at the end of each days operations if odor

or volatilization of contaminants becomes a problem. 

(8) Daily cover normally consists of a minimum of 6 inches of

soil. However, foams and geosynthetics have been used as daily cover

on some projects. 

(9) When regrading waste prior to placement of a landfill

cover, look for leachate seeps that present unsuitable conditions for

fill placement. These seeps should be reported to the designer.

(10) Verify the final lines and grades of the regraded waste

are correct. 

c. Compaction of Waste. Compaction of waste is important in

preventing damage to the landfill cover due to differential

settlement.

(1) Waste compaction equipment typically weighs 18,000 to

32,000 kg (40,000 to 70,000 pounds). Check the specifications for

equipment weight or compaction pressure requirements. 

(2) Compaction of waste is usually specified by requiring

several passes of a compactor over all areas of the waste instead of

requiring that a specific density criteria be achieved. The number of

passes required is site specific and should be addressed in the

specifications. Spot-check to make sure the contractor is making the

minimum required number of passes for each lift of waste placed. 

(3) For landfill liners, verify the contractor’s method of 
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3.2-3

placement does not damage the liner system. 

(4) Compaction equipment should be operated so that the

compactor overlaps the rolled adjacent strip by not less than 0.3

meters (12 inches). 

(5) Check for areas where additional fill needs to be placed

due to settlement.

d. Subgrade. Subgrade is the term commonly used to describe

the soils placed immediately beneath the landfill cover or liner. 

This layer provides a foundation layer for the landfill cover or liner

and is typically a minimum of 0.3 meters (12 inches) in thickness.

(1) Determine from the contract drawings whether on-site or

off-site borrow will be used for the subgrade soil.

(2) If on-site borrow will be used, is there sufficient

quantity?

(3) Verify the subgrade soils meet the specified requirements

for soil type and gradation.

(4) Verify subgrade soils are placed to the lines and grades

shown on the drawings and compacted and tested in accordance with the

specifications.

(5) Compaction criteria are often waived for the first lift of

the subgrade layer when it is placed on top of compressible waste

because it is difficult to get adequate compaction.

(6) Inspect for erosion in the surface of the subgrade and

require the contractor to reshape and regrade damaged areas.
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3.3-i

CHAPTER 3.3

LOW PERMEABILITY CLAY LAYER

Paragraph Page

3.3-1 GENERAL 3.3-1

a. Equipment 3.3-1

b. Preconstruction Submittals 3.3-2

c. Construction Submittals 3.3-2

3.3-2 PRODUCTS 3.3-2

a. Low Permeability Clay 3.3-2

b. Bentonite 3.3-3

3.3-3 EXECUTION 3.3-3

a. Subgrade Preparation 3.3-3

b. Installation 3.3-3

c. Tests 3.3-5

d. Protection 3.3-7

e. Repairs 3.3-8
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3.3-1

CHAPTER 3.3 LOW PERMEABILITY CLAY LAYER

3.3-1. GENERAL. The purpose of the low permeability clay layer in a

landfill cover or liner system is to inhibit the movement of water

into or out of the waste. Soils used for the clay layer are selected

to meet a specific hydraulic conductivity requirement (typically 1 ×

10 cm/sec). If suitable clay materials are not found in the vicinity -7

of the project, a common practice is to blend available soils with

bentonite. The following steps are required to properly construct a

low permeability clay layer: & locate and test borrow sources to ensure appropriate clay

material is available;

& preprocess soil liner material, if necessary, to adjust

the water content, to remove oversized particles, to break

down clods of soil, or to add amendments such as

bentonite;

& prepare the subgrade to provide a firm foundation on which

to place clay;

& place and compact the clay material at the appropriate

moisture content and density. Clay barrier layers are

normally a minimum of 600 mm (24 inches) in thickness. 

They are typically placed in several lifts with a

compacted lift thickness of approximately 150 mm (6

inches). Heavy compactors with feet that penetrate the

loose lifts of soil are ideal for compaction of clay

layers. The Caterpillar 815B and 825C are examples of

equipment that have been successfully used for compaction

of clay layers; & freeze-thaw cycles and desiccation cracks will increase

the hydraulic conductivity of a clay layer. Therefore, it

is critical to protect the clay layer until the layer is

completed and covered.

a. Equipment.

(1) Compaction Equipment.

(a) Verify the compaction equipment proposed for use are 

footed rollers. The compactors should also meet the weight

requirements described in the specifications. 

(b) During compaction operations, the spaces between the

tamping feet should be kept clear of materials. 

(c) Do not allow compaction equipment to be operated at speeds

exceeding specified limits (generally 2.2 meters per second (5.0 miles

per hour)). 

(2) Scarification Equipment. Verify scarification equipment is

capable of scarifying to the depth specified (generally 25 to 50 mm (1

to 2 inches)).

(3) A smooth steel wheeled non-vibratory roller should be used

to produce a smooth compacted surface on the final lift of the clay

layer if a geomembrane will be placed on top of the clay layer. 

(4) Ensure hand operated tampers consist of impact type 
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3.3-2

equipment. Vibratory type equipment should not be allowed.

b. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Materials Handling Plan which describes the processing, 

placement, and protection of the clay layer. 

(a) The contractor’s plan for protecting the clay layer should

address how the clay will be kept at the correct moisture content

after placement (this includes evenings and weekends). 

(b) Generally, construction of the cover or liner should

progress in stages so the clay layer is periodically covered by other

soil layers in order to provide protection from desiccation and

freeze/thaw damage. Covering the clay layer with geosynthetics only

may not provide adequate protection.

(2) Name and qualifications of the proposed commercial testing

laboratory.

(3) Borrow Source Assessment Report. Borrow source assessment

testing is sometimes done during the design phase. If this is the

case, the amount of borrow source assessment testing done by the

contractor will be greatly reduced.

(a) Borrow assessment tests should be performed on each type of

soil proposed for use to develop compaction requirements for

placement. At a minimum, one set of borrow assessment tests should be

performed for each borrow source. A set of borrow source assessment

tests generally consists of classification testing, moisture-density

(compaction) testing, and hydraulic conductivity testing. 

(b) An "Acceptable Zone" of moisture contents and densities

which meet the hydraulic conductivity criteria should be developed and

displayed on the compaction curve graphs.

(4) Samples of low permeability clay, if required.

c. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Borrow classification test results. 

(2) Subgrade test results.

(3) In-place moisture content and density test results.

(4) In-place hydraulic conductivity test results.

3.3-2. PRODUCTS

a. Low Permeability Clay.

(1) For composite geomembrane/clay covers and liners, the

maximum particle size is typically 12.5 mm (0.5 inches) in the upper

lift of clay to prevent puncturing of the geomembrane. 
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3.3-3

(2) The maximum allowable particle size will typically be 25-50

mm (1-2 inches) in the rest of the clay layer.

(3) Check the properties of the clay material being submitted

against the requirements listed in the specifications. 

(4) At sites where multiple borrow sources are used for clay,

ensure the correct compaction curve is used for each type of soil

being placed.

(5) Perform daily inspections of stockpiles or borrow sources

to see if there are visible changes in the properties of the borrow. 

Additional borrow source assessment testing may be required if it

appears the properties of the borrow source are changing.

b. Bentonite. If bentonite is used to improve the

characteristics of the soil, the following paragraphs describe items

which the QA Representative should monitor. 

(1) Ensure that the bentonite has been pulverized to the extent

required by the specifications. A fine powdered bentonite will behave

differently than a coarse, granular bentonite. Check grain size

distribution test results and also visually monitor the bentonite for

changes in grain size distribution.

(2) Free swell (ASTM D 5890-95) , fluid loss (ASTM D 5891-95)

and other tests are also commonly specified to ensure a high quality

bentonite is being used. Verify these results meet the specified

requirements. 

(3) The bentonite and soil are commonly mixed together using a

pug mill. An alternative mixing technique is to spread the soil in a

loose lift, distribute bentonite on the surface, and mix the bentonite

and soil using a rototiller or other mixing equipment. Visually

inspect the mixing process to ensure that the bentonite is uniformly

mixed throughout the entire lift of soil. The specifications may also

require QC and QA testing be performed to verify the uniformity of

mixing.

3.3-3. EXECUTION

a. Subgrade Preparation.

(1) Verify that the subgrade is composed of satisfactory

materials as defined by the specifications. 

(2) Check in-place density test results against specified

requirements.

(3) Verify the lines and grades of the top surface of the

subgrade are correct prior to clay placement. 

(4) The subgrade surface should be scarified prior to placement

of the first lift of clay to minimize preferential flow paths along

the interface and to eliminate the development of a potential slip

plane.

b. Installation.

(1) Clay Placement.
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3.3-4

(a) Carefully inspect placement and compaction of clay placed

above geosynthetic layers. Look for slippage of the compaction

equipment on slopes which can cause tension in the geosynthetics. 

Also look for thin areas of clay which could allow the geosynthetics

to be punctured or torn.

(b) Verify loose lifts are no greater than the specified

maximum thickness (generally 205 to 230 mm (8 to 9 inches)). In areas

where hand operated tampers must be used, the loose lift thickness

should not exceed 102 mm (4 inches). The most common way to determine

the loose lift thickness is to stand near the working face and observe

the lift being placed. 

(c) Periodically measure the loose lift thickness by digging a

pit through the loose lift of soil and into the underlying layer. A

cross-beam is then used to measure the depth from the surface of the

loose lift to the top of the previously compacted lift. The zone of

scarification should be counted in the loose lift thickness for the

new lift of soil. 

(d) Verify the clay contains no large clods or other material

prohibited in the specifications. This can be done by positioning

yourself near the working face as the soil is being placed and

visually inspecting for stones, organic matter, debris and other

material which is unacceptable.

(e) If highly plastic soils are being used, pay particular

attention to preprocessing of clods, breaking up of clods during

compaction, and protection from desiccation. No standard method is

available to determine clod size. Inspectors should observe the soil

liner material and periodically determine the dimensions of clods by

direct measurement.

(f) Verify clay is being placed to the lines and grades shown

on the drawings.

(g) Grade stakes should be numbered and they should be

accounted for at the end of each shift.

(2) Moisture Control.

(a) Verify clay is placed and compacted within the approved

moisture content range.

(b) Inspect the entire lift thickness to verify the moisture

content is uniform throughout the lift. 

(c) A spreader bar on the back of a water truck is the

recommended device for moistening the clay. A disk or rototiller is

then used to mix the water into the lift of clay.

(d) If water is being added to the clay layer, cure time is

required to obtain uniform moisture. Require additional moisture

content tests to be run if there is a question about the uniformity of

the moisture content within a lift. 

(3) Compaction. 

(a) Refer to Section 3.9 Cover Soil, if the first lift of clay

will be placed directly on top of geosynthetic layers.

(b) Verify the clay is compacted to the density requirements in 
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3.3-5

the approved Borrow Source Assessment Report.

(c) Check to see if the specifications require a minimum number

of passes by the compaction equipment. Spot check the contractor

daily to ensure the correct number of passes are being used to compact

the clay layer.

(d) Review the specifications to determine if there are any

special requirements for compaction around pipes and other

penetrations. 

(e) Verify that soil placed around pipes and other penetrations

does not contain voids and is adequately compacted. 

(f) Inspect pipes which penetrate the clay layer for damage due

to the compaction process. 

(4) Scarification.

(a) Verify that all areas of the upper surface of each lift are

scarified prior to placement of the next lift of clay. 

(b) The final lift of clay should be rolled with a smooth steel

wheeled roller if a geomembrane will be placed above the clay layer. 

Check the specifications to determine the minimum number of passes

required. 

c. Tests.

(1) Borrow Tests.

(a) Check borrow test results (moisture content, sieve

analysis, Atterberg limits, and compaction tests) to verify that the

borrow material being excavated is uniform. As an approximate guide,

a relatively homogeneous borrow soil would be considered a soil in

which optimum moisture varies by no more than +/- 3 percent and

maximum density varies by no more than +/- 80 kg/cubic meter (5

lbs/cubic foot).

(b) Additional borrow assessment testing should be performed if

the properties of the borrow source change. The contractor and QA

personnel should agree on what constitutes a significant change in the

borrow source prior to the start of construction. 

(c) For highly variable borrow sources, it is recommended that

an inspector observe all excavation of borrow soil in the borrow pit. 

This is the best way to monitor for changes in soil type. A useful

guide in helping you to perform field identification of soils is ASTM

D-2488, “Description and Identification of Soils (Visual-Manual

Procedure).” A key factor to look for during excavation of the

borrow pit are changes in plasticity of the clay. 

(2) In-Place Moisture Content and Density Tests.

(a) Typically, moisture content and density tests are performed

in an evenly spaced grid pattern. The grid pattern should be

staggered for successive lifts so that sampling points are not at the

same location in each lift. 

(b) Verify that moisture content and density test results fall

within the "Acceptable Zone" for the material type being tested. 
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3.3-6

(c) If test results are not within the "Acceptable Zone",

additional tests should be taken in the area where the failed test was

made. If all of the repeat tests pass, the failed test result may be

ignored. If any of the additional tests fail, repairs should be

performed.

(d) The contractor should submit documentation describing the

corrective measures taken in response to failed test results.

(e) Verify moisture content and density tests are performed

using specified test procedures.

(f) At the beginning of a project, at least 10 measurements of

moisture content and density should be made on representative samples

of site-specific soil using any rapid measurement methods proposed for

use. These results should be compared against test results using

standard test methods to verify there is good correlation.

(g) Verify nuclear gauges are standardized daily on a reference

standard in accordance with ASTM D 2922 and ASTM D 3017. 

(h) Make sure the contractor uses nuclear gages in the direct

transmission mode to measure density. This means the probe is

inserted into a hole in the soil layer. The probe rod is then pressed

against the surface of the hole closest to the detector and the

density measurement is taken. 

(i) Nuclear gages are used in the back-scatter mode to measure

moisture content. This means the probe is not inserted into the clay

layer.

(j) The most serious potential source of error in using nuclear

gages is improper use by the operator. One gross error that is

sometimes made is to drive the source rod into the soil rather than

inserting the source rod into a hole that has been made with a drive

rod. Other sources of error include the following: improper

separation of the source from the side and base of the hole, an

inadequate period of counting, inadequate warm-up of the device, other

sources of gamma radiation, and infrequent calibrations.

 (k) Rapid moisture content tests taken using either the nuclear

gage (ASTM D-3017) or microwave method (ASTM D-4643) should be checked

periodically (one in every ten tests is typical) using the standard

method for determining moisture content (ASTM D-2216). This is

especially critical when the contractor is using a nuclear gauge

because they are susceptible to interference which results in the

gauge overestimating moisture content.

(l) Rapid nuclear density tests (ASTM D-2922) should be checked

periodically (one in every twenty tests is typical) using a standard

method such as the sand cone (ASTM D-1556) or rubber balloon (ASTM D2167). 

(m) When checking the accuracy of rapid moisture content and

density tests, the standard moisture and density tests should be taken

at the same location as the rapid tests so that results can be easily

compared.

(n) When observing the contractor performing sand cone tests,

check to make sure the hole dug in the soil layer does not contain

rough edges or overhangs that can produce voids in the sand filled

hole. Also inspect the sand to make sure it is not contaminated with 
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3.3-7

soil particles. Vibrations from equipment working nearby can also

affect sand cone test results by densifying the sand.

(o) When inspecting rubber balloon tests being performed, check

the excavated hole for rough edges which leave small zones that cannot

be filled with the pressurized balloon. 

(p) A minimum of one moisture content and density test should

be performed each day that clay is placed. 

(3) In-Place Hydraulic Conductivity Tests.

(a) Verify undisturbed samples are taken for hydraulic

conductivity testing at the specified frequency for each lift of clay

placed. 

(b) Verify the samples are collected and tested using the

procedures described in the specifications. Thin-walled sampling

tubes should be pushed (not pounded) into the clay perpendicular to

the plane of compaction. 

(c) Hydraulic conductivity testing is generally performed in

accordance with ASTM D-5084. The specifications should indicate the

confining pressure and head to be used for testing the samples. 

Contact the design district if this information is not provided. 

Typically, a confining pressure of 35 kPa (5 psi) is recommended for

both liner and cover systems. 

d. Protection.

(1) Clay placement and compaction should not take place if the

temperature is below 0 degrees C (32 degrees F) or if it is raining.

(2) Excess Surface Water.

(a) Puddles and excess moisture should be removed by replacing

the wet soil, discing, or allowing the soil to dry prior to placement

of additional clay. 

(b) Look for areas of erosion after each rainfall. Require the

contractor to repair areas of erosion and reestablish grades.

(c) Reworked areas should be retested for moisture content and

density as described in Paragraph e. Repairs. 

(3) Desiccation and Freezing.

(a) Ensure the contractor keeps the clay surface moist at all

times so that desiccation cracks are minimized. The allowable size of

desiccation cracks is often not addressed in the specifications. If

this is the case, discuss this issue with the contractor prior to

construction so that criteria acceptable to both, is agreed upon. 

Typically, cracks which are no greater than 6 mm wide by 51 mm deep

(.25 inches wide by 2 inches deep) are not considered a problem.

 (b) The clay layer should be covered as quickly as possible

with other soil layers. Geosynthetics alone may not provide adequate

protection.

(c) Require additional moisture content tests be performed if

there are indications the clay is drying out. A decrease in the

moisture content of one to two percent is not considered serious and
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3.3-8

within the general accuracy of testing. However, larger reductions in

moisture content provide clear evidence that desiccation has taken

place.

(d) The clay layer may be tested at multiple depths to get a

better feel for variations in moisture content. 

(e) If the subgrade soils are dry they may also be pulling

moisture out of the clay.

(f) Inspect for cracking or other damage if the clay layer is

exposed to freezing temperatures. It is difficult to determine the

depth to which freezing took place by examining the surface of the

clay layer. Dig into the clay layer and look for hairline cracks. 

Also look for areas where the soil breaks apart into chunks along

cracks caused by freezing. 

(g) Freeze/thaw is often accompanied by desiccation. Require

the contractor to measure moisture content of the clay within and

beneath the zone of suspected frost damage. Density may also be

measured. However, freeze/thaw often has little effect on density. 

(h) If freeze/thaw damage is suspected, samples can also be

hand trimmed from the clay layer for hydraulic conductivity testing. 

Sampling tubes should not be pushed into a clay layer suspected of

having freeze/thaw damage because this procedure will probably close

the cracks caused by the freeze/thaw.

e. Repairs. If the clay layer does not conform to the

specifications, the first step is to define the extent of the area

requiring repair. 

(1) Require the contractor repair the lift of clay out to the

limits defined by passing QC or QA tests. 

(2) Do not allow the contractor to guess at the extent of the

area that requires repair. To define and minimize the limits of the

area to be repaired, additional tests are often performed.

(3) Once the area requiring repair has been defined, the area

should be thoroughly disced, reworked, and recompacted. If the depth

of soil requiring repair is greater than one lift, it may be necessary

to strip away and replace the clay.

(4) After repairs have been made, the repaired areas should be

tested at the same frequency as required for the rest of the project. 

(5) Ensure that voids in the clay created for tests, samples,

and grade stakes are repaired by placing and compacting clay backfill

or bentonite in the voids. The backfill material should be placed in

the hole in loose lifts (typically 50 mm (2 inches) thick) and tamped

several times with a steel rod prior to placing the next lift. 

(6) If sand cone density tests are performed, verify the sand

is removed prior to repairing the void. 
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3.4-i

CHAPTER 3.4

GEOSYNTHETIC CLAY LINER (GCL)

Paragraph Page

3.4-1 GENERAL 3.4-1

a. Preconstruction 3.4-1 

 Submittals

b. Delivery, Storage, 3.4-1

 and Handling

c. Weather Limitations 3.4-2

3.4-2 PRODUCTS 3.4-2

Geosynthetic Clay Liner 3.4-2

3.4-3 EXECUTION 3.4-2

a. Subgrade Preparation 3.4-2

b. Installation 3.4-3

c. Repairs 3.4-4

d. Penetrations 3.4-4

e. Covering 3.4-4
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3.4-1

CHAPTER 3.4 GEOSYNTHETIC CLAY LINER (GCL)

3.4-1. GENERAL. Geosynthetic clay liners (GCLs) are factory

manufactured hydraulic barriers consisting of bentonite clay materials

supported by geotextiles or geomembranes. GCLs are used to augment or

replace compacted clay layers or geomembranes. All of the GCL

products available in North America use sodium bentonite in powder or

granular form. The bentonite thickness of the products vary between

4.0 to 8.0 mm (160 to 320 mils). GCLs are available in widths of 2.2

to 5.2 m (7 to 17 ft) and lengths of 30 to 60 m (100 to 200 ft). GCLs

are most often considered for use where there is a limited supply of

natural clay or limited landfill space. GCLs are also less

susceptible to the effects of desiccation and freeze/thaw than natural

clay layers. 

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) The manufacturer's QC manual and QC test results.

(2) GCL roll layout and penetration details. 

(3) Qualifications for the manufacturer, installer, inspector

(if required), and QA laboratory (if required).

(4) Mid-plane and interface friction test results.

(5) Sample of GCL (if required). 

b. Delivery, Storage, and Handling.

(1) A QA Representative should be present during delivery and

unloading of the GCL to inspect for damage. 

(2) Verify rolls are labeled with the manufacturers name,

product identification, lot number, roll number, roll dimensions, roll

weight, and date manufactured.

(3) The QA Representative should record applicable roll

numbers, date delivered, name of manufacturer, and product type. This

data is used to verify manufacturer’s QC data sheets have been

submitted for the rolls being delivered.

(4) Verify each GCL roll is wrapped around a central core and

covered with an opaque, waterproof, protective covering. Require that

tears in the packaging be repaired using tape and plastic sheeting to

restore a waterproof protective barrier around the GCL.

(5) Do not allow rolls to be dragged, lifted by one end, or

dropped to the ground.

(6) A pipe or solid bar of sufficient strength to support the

full weight of the roll without significant bending should be used for

all handling activities. Chains should be used to link the ends of

the core pipe to the ends of a spreader bar. The spreader bar should

be wide enough to prevent the chains from rubbing against the ends of

the GCL rolls. 
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3.4-2

(7) Alternatively, a stinger bar protruding from the end of

forklift or other equipment may be used. The stinger bar should be at

least three-fourths the length of the core and also must be capable of

supporting the full weight of the GCL without significant bending.

(8) If recommended by the manufacturer, a sling handling method

utilizing loading straps may be used for handling. 

(9) Verify rolls are stored in a flat dry area where water

cannot accumulate. If rolls are elevated off the ground using blocks

or pallets, make sure the entire roll bottom is supported. 

(10) Do not allow rolls of GCL to be stacked more than three

high.

c. Weather Limitations. GCL should not be deployed if

precipitation is likely to hydrate the bentonite prior to placement of

a geomembrane or cover soils. 

3.4-2. PRODUCTS.

Geosynthetic Clay Liner.

(1) Cross check the roll numbers of the GCL delivered to the

site against the roll numbers on the manufacturer’s QC test data

submittals to ensure they match. Ensure the GCL meets the property

requirements outlined in the specifications for material type and

physical properties (bentonite mass per unit area, free swell of

bentonite, hydraulic conductivity, etc...). 

(2) If a geotextile backed GCL is being used, verify the two

layers of geotextile surrounding the bentonite are stitch-bonded or

needle-punched together. 

(3) Verify friction test results indicate adequate interface

shear strength exists between the GCL and adjacent materials. 

(4) GCLs must also be tested for internal shear strength. 

Verify internal shear strength results meet the specified

requirements.

3.4-3. EXECUTION.

a. Subgrade Preparation.

(1) Inspect the subgrade daily to ensure it is smooth and free

of vegetation, standing water, sharp-edged rocks, or any other

material that could damage the GCL. The condition of the subgrade is

generally certified in writing by the QA Representative and installer

each day prior to GCL placement. 

(2) Verify the final lines and grades of the subgrade are

correct prior to GCL placement.

(3) Typically the subgrade surface is rolled with a smooth-drum

compactor of sufficient weight to remove any protrusions, wheel ruts,

footprints, or other abrupt changes in grade. 

(4) Typically, specifications will require the repair of ruts
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3.4-3

 or protrusions greater than 12.5 mm (.5 inches) in depth or height. 

(5) Do not allow the use of calcium rich soil, such as

limestone, in the subgrade because it will reduce the effectiveness of

the GCL.

b. Installation.

(1) A QA Representative should be present at all times during

GCL installation.

(2) Protective plastic covering should not be removed from a

roll of GCL until immediately prior to deployment.

(3) Do not allow personnel working on the GCL to smoke or wear

shoes which could damage the GCL.

 (4) Ensure equipment used to deploy the GCL will not damage

geosynthetics located beneath the GCL.

(5) GCL rolls should be slowly unrolled. Do not allow the

contractor to freely roll GCL down the slopes.

(6) Care must be taken to minimize the extent to which the GCL

is dragged across the subgrade in order to minimize damage to the

bottom surface of the GCL. GCL is often placed on sheets of plastic

(slip sheets) so it can be moved without being damaged. 

(7) Ensure the deployed GCL is smooth and free of wrinkles. 

(8) Check the specifications for overlap requirements. 

Generally, GCL rolls should be overlapped a minimum of 150 mm (6

inches) for roll sides and 450 mm (18 inches) for roll ends. 

(9) Ensure the overlap areas are free of dirt. 

(10) On warm days, some GCLs tend to shrink. This reduces the

overlap present along the sides and ends. Periodically check the

overlaps. If significant shrinkage has occurred (25 to 50 mm (1 to 2

inches)) contact the designer to see if the GCL should be

repositioned.

(11) GCL should generally be placed parallel to the line of

maximum slope. For any horizontal seams on slopes, ensure overlaps

are constructed with the up slope GCL shingled over the down slope

GCL.

(12) Check the manufacturer’s recommendations to determine if

there are any special seaming requirements for horizontal seams

constructed on slopes.

(13) Granular bentonite is sometimes placed along GCL seams if

the GCL is constructed using nonwoven geotextiles. Check

manufacturer’s recommendations for proper seam construction

procedures.

(14) GCL should not be left uncovered overnight. Require

temporary plastic covers to be placed over exposed GCL. 

(15) If exposed to water prior to being covered, check to see

if the GCL has become hydrated. Hydrated GCL is often defined as

material which has become soft as determined by squeezing the 
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3.4-4

material with finger pressure or material which has exhibited

swelling. Another indication that hydration has occurred is the

presence of bentonite swelling through the void spaces of the

geotextile backing material. Contact the designer if it appears the

GCL has become hydrated.

(16) Any area requiring repair should be clearly marked on the

GCL.

c. Repairs. Patches should be constructed and secured as

recommended by the manufacturer. Generally, patches for holes and

tears should extend a minimum of 300 mm (12 inches) beyond the edge of

the defect.

d. Penetrations. Penetration details should be constructed as

recommended by the manufacturer. This will generally involve a collar

of GCL wrapped around the pipe and hand placement of dry bentonite.

e. Covering. Refer to Chapter 3.9 Cover Soil Layer for

additional information on cover soil placement.
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3.5-i

CHAPTER 3.5

GEOMEMBRANE

Paragraph Page

3.5-1 GENERAL 3.5-1

a. Preconstruction 3.5-1

 Submittals

b. Construction Submittals 3.5-1

c. Delivery, Storage, 3.5-2

 and Handling

d. Weather Limitations 3.5-2

3.5-2 PRODUCTS 3.5-3

Geomembrane 3.5-3

3.5-3 EXECUTION 3.5-3

a. Subgrade Preparation 3.5-3

b. Geomembrane Deployment 3.5-3

c. Spotting 3.5-4

d. Seams 3.5-5

e. Trial Seams 3.5-5

f. Field Seams 3.5-6

g. Field Sampling and 3.5-9

 Testing

h. Defects and Repairs 3.5-11

i. Penetrations and Connections 3.5-11

j. Covering 3.5-12
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3.5-1

CHAPTER 3.5 GEOMEMBRANE

3.5-1. GENERAL. Geomembranes are thin sheets of flexible, relatively

impervious, plastic materials whose primary function is to act as a

barrier to liquids and vapors. The plastic materials are manufactured

into sheets and transported to the job site where placement and field

seaming are performed. The most common types of geomembranes

currently being used for landfill covers are polyvinyl chloride (PVC)

and various forms of very flexible polyethylene (VFPE). A minimum

thickness of 1.0 mm (40 mils) is often specified for cover

geomembranes due to constructibility concerns. High density

polyethylene (HDPE) is generally not used for landfill covers when a

large amount of differential settlement is anticipated because it is

less flexible than PVC or VFPE which makes it more susceptible to

damage by differential settlement. HDPE does have very good

resistance to chemical attack, therefore, it is commonly used for

liner systems where less differential settlement is expected and

resistance to chemical attack is important. A minimum thickness of

1.5 mm (60 mils) is often specified for liner geomembranes. 

Geomembranes can be manufactured with textured surfaces which improve

their interface frictional resistance. Textured geomembranes are

generally not used unless the slopes of the cover or liner are equal

to or steeper than 1V on 4H. In general, textured geomembranes are

more expensive, have diminished physical properties, have more

manufacturing defects, and are more difficult to field seam and

inspect than non-textured geomembranes. 

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Manufacturer's QC manual and QC test results. 

(2) Installers QC manual. Verify the installer has been

approved by the manufacturer.

(3) Geomembrane panel layout and penetration detail drawings. 

For landfill liners, the panel layout should be arranged so that the

number of seams in the sump bottom are minimized or eliminated.

(4) Manufacturer's, fabricator's, installer's, inspector's, and

QA laboratory's qualification statements including resumes of key

personnel involved in the project. 

(5) Interface friction test results. 

(6) Sample of geomembrane (if required).

b. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Final as-built drawings of the geomembrane installation

showing sheet numbers and seam numbers. The locations of repairs,

destructive seam samples, and penetrations should also be shown. 

(2) Field test results for geomembrane thickness.

(3) Field seam test results for leaks, shear strength, and peel

strength.
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3.5-2

(4) QA test results for shear and peel strength.

(5) Seam samples for permanent record (if required). 

c. Delivery, Storage, and Handling. 

(1) A QA Representative should be present during delivery and

unloading of the geomembrane to inspect for damage.

(2) Verify that rolls are labeled with the manufacturer's name,

product identification, lot number, roll number, roll dimensions, and

date manufactured.

(3) The QA Representative should record roll numbers, date

delivered, name of manufacturer, and product type. This data is used

to verify manufacturer's QC data sheets have been submitted for the

rolls being delivered. 

(4) Geomembrane rolls should be handled and unloaded with load

carrying straps, a fork lift with a stinger bar, or an axial bar

assembly should be used.

(5) Do not allow rolls to be dragged, lifted by one end, or

dropped to the ground.

(6) The geomembrane should be protected from puncture,

abrasion, excessive heat and cold, or other damaging conditions during

storage. 

(7) Temporary storage should be in a flat dry area where

standing water cannot accumulate. Verify the ground surface contains

no stones or other sharp objects.

(8) Ensure that rolls of geomembrane are not stacked more than

5 high.

(9) Do not allow pallets of accordion folded geomembrane (PVC)

to be stacked on top of each other. 

d. Weather Limitations. 

(1) Geomembrane should be deployed and field-seamed only when

the geomembrane is dry. 

(2) Check manufactures recommendations for allowable

temperatures for deployment and seaming.

(a) On hot days, watch the geomembranes as they are unrolled or

unfolded to see if they stick together to the extent where tearing or

straining of the geomembrane occurs. The upper limit for sheet

temperature is very specific to the type of geomembrane. Geomembrane

should not be deployed if this temperature is exceeded unless it can

be shown that the geomembrane is not being damaged.

(b) A sheet temperature of 0 degrees C (32 degrees F) is

typically the lower limit at which geomembrane should be unrolled or

unfolded unless it is shown that the geomembrane can be deployed

without being damaged. 

(3) In marginal weather conditions, require the contractor to

make test seams to confirm that satisfactory seams can be constructed. 
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3.5-3

3.5-2. PRODUCTS.

Geomembrane.

(1) Cross check the roll numbers of the geomembrane delivered

to the site against the roll numbers on the manufacturer’s QC test

data to ensure they match. Ensure the geomembrane meets the property

requirements outlined in the specifications for material type and

physical properties.

(2) Polyethylene seaming rods and pellets should be

manufactured of resin which is essentially identical to that used in

the geomembrane. 

(3) For textured geomembranes, visually inspect the texturing

as the rolls are being deployed. Make sure the texturing is uniform

over the entire roll. 

3.5-3. EXECUTION.

a. Subgrade Preparation 

(1) The condition of the subgrade should be checked by the QA

Representative and installer each day that geomembrane is placed. The

condition of the subgrade is generally certified in writing by the QA

Representative and installer each day prior to geomembrane placement.

(2) Verify the final lines and grades of the subgrade are

correct prior to geomembrane placement. 

(3) Ensure that surfaces to be lined with geomembrane provide a

firm, unyielding foundation with no sharp breaks in grade. 

(4) Soil subgrade should be rolled with a smooth drum compactor

of sufficient weight to remove any protrusions, wheel ruts, foot

prints, or other abrupt changes in grade.

(5) Inspect for rocks larger than specified requirements

(typically 12.5 mm (1/2 inch) in diameter) or any other debris which

could damage the geomembrane. This material should be removed from

the upper lift of soil layers to be covered with geomembrane.

(6) Verify that construction equipment used to deploy 

geomembrane does not deform or rut the subgrade. Typically, ruts

should not be greater than 25 mm (1.0 in.) in depth. 

b. Geomembrane Deployment. 

(1) A QA Representative should be present at all times during

geomembrane installation. 

(2) To avoid confusion, the installer and QA Representatives

should use different colored markers that are easily visible on the

geomembrane. The markers should be semi-permanent and compatible with

the geomembrane. 

(3) Look for damaged geomembrane during installation. Damage

may include things such as permanent creases, folds, crimps, gouges,

holes, scratches, and inadequate texturing. Any area requiring 
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3.5-4

repair should be clearly marked.

(4) Carefully inspect deployed geomembrane for damage if it has

been displaced by wind. 

(5) Do not allow personnel working on the geomembrane to smoke

or wear shoes which could damage the geomembrane.

(6) Only geomembrane that can be anchored and seamed together

the same day should be deployed. 

(7) Ensure geomembrane panels which have been deployed are

secured with acceptable ballast to prevent uplift by wind. 

(8) Sand bags are typically used for ballast. A continuous

line of sand bags should be placed along all exposed edges of

geomembrane.

(9) Seams should be oriented parallel to the line of maximum

slope. 

(10) Where seams can only be oriented across the slope, verify

the upper sheet is lapped over the lower sheet. 

(11) If a composite liner (geomembrane/clay) is being

constructed, make sure the geomembrane is placed directly on the

underlying clay layer. Other geosynthetics should not be placed

between the geomembrane and the clay layer. Slip sheets are sometimes

used to position textured geomembranes. Verify the slip sheets are

removed after the geomembrane has been correctly positioned. 

(12) There should be sufficient slack in the deployed

geomembrane to prevent tensile stresses from occurring when the

temperature drops, causing the geomembrane to shrink.

(13) The trampoline effect occurs when a membrane shrinks and

pulls away from the subgrade at corners. Inspect for the trampoline

effect in the morning when temperatures are lowest. The trampoline

effect often occurs along the bottom edge of liner systems.

(14) Ensure that the geomembrane does not have excessive slack

to the point where folds in the geomembrane lay over during placement

and covering.

(15) Inspect the surface of the deployed membrane in the

morning for evidence of protrusions in the subgrade. Subgrade

protrusions are more easily identified in the morning because the

membrane has contracted due to the cooler night time temperatures. 

(16) Verify that each deployed geomembrane panel is given a

panel number which is recorded on the daily reports and as-built

drawings.

c. Spotting. 

When a geomembrane roll or panel is deployed it is generally

required that some shifting will be necessary before field seaming

begins. This is called spotting by many installers. 

(1) Spotting of deployed geomembranes should be done without

disturbing the subgrade soil or geosynthetic materials.
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3.5-5

(2) Temporary tack welding (usually with a hand held hot air

gun) of all types of thermoplastic geomembranes should be allowed at

the installers discretion.

(3) When temporary tack welds are used, verify the welds do not

interfere with the primary seaming method, or with the ability to

perform subsequent destructive seam tests. Tack welds should not be

strong enough to produce a film tearing bond.

d. Seams. Geomembrane seams fall into four general categories

which are described below. This document will focus on extrusion and

thermal fusion seams since they are the most common seam types used on

projects the Corps of Engineers has been involved with. Additional

information on the fabrication of geomembrane field seams can be found

in EPA/530/SW-91/051.

& Extrusion Welding Seams. A ribbon of molten polymer is

extruded over the edge of, or in between, the two surfaces

to be joined. The molten extrudate causes the surfaces of

the sheets to become hot and melt, after which the entire

mass cools and bonds together. This type of seam is used

for polyethylene geomembranes.

& Thermal Fusion. The surfaces of geomembranes are melted

using an electrically heated resistance element in the

shape of a wedge that travels between the two sheets to be

seamed. The geomembranes are then pressed together using

a set of rollers. A double wedge weld is usually used. A

double wedge weld is created with a split wedge which

forms two parallel seams with a uniform unbonded space

between them. This space can be used to evaluate seam

quality and continuity by pressurizing the unbonded space

with air and monitoring for drops in pressure. This type

of seam can be used for polyethylene, chlorosulfonated

polyethylene, or PVC geomembranes.

& Chemical Fusion. Chemical fusion seams make use of a

liquid chemical applied between the two geomembrane sheets

to be joined. After a few seconds (required to soften the

geomembrane surfaces) pressure is applied to make complete

contact and bond the sheets together. Bodied chemical

fusion seams are similar to chemical fusion seams except

that geomembrane resin is added to the adhesive to

increase the viscosity of the liquid for use on slopes or

to adjust the evaporation rate of the chemical. This type

of seam can be used for PVC or CSPE geomembranes.

& Adhesive seaming. Adhesives are applied to both

geomembrane surfaces. After reaching the proper degree of

tackiness, the two geomembrane sheets are placed on top of

one another, followed by application of roller pressure. 

This type of seam can be used for PVC or CSPE

geomembranes.

e. Trial Seams. 

(1) Trial seams should be made on test strips of excess

geomembrane under field conditions to verify that seaming methods are

adequate. Make sure trial seams are constructed in the same weather

conditions as the actual field seams.

(2) Require trial seams to be made each day prior to production

seaming, whenever there is a change in seaming personnel or seaming
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3.5-6

equipment, and at least once every four to five hours. 

(3) Require additional trial seams if there is a quick change

in weather conditions (temperature and/or sunlight) which causes a

significant change in the temperature of the geomembrane. 

(4) A QC sample should be obtained from each trial seam with

the seam centered lengthwise. For some projects, a QA sample and an

archive sample may also be collected from the trial seam. Ensure each

trial seam sample is adequately labeled with the sample number, date,

who will test the sample, ambient temperature, and any other

information required by the QA plan or specifications. 

(5) Typically, 6 to 10, 2.54 cm (1 inch) wide specimens

(coupons) are cut from the sample for testing by the geomembrane

installer. Half of the seam specimens will be tested for shear

strength and half for peel adhesion using an approved tensiometer with

a digital readout. 

(6) Ensure field tensiometers used have an up to date

calibration certificate.

(7) Require a second trial seam be made if tests from the

initial trial seam fail. 

(8) If the additional trial seam fails, the seaming apparatus

or seamer should not be used until the deficiencies are corrected and

two consecutive successful trial seams are made. 

(9) While the test seams are being tested, the seaming crew may

continue to work as long as the seams they make since their last

acceptable test sample strip was prepared are completely traceable and

identifiable.

(10) The QA Representative should ensure the following

information is recorded for each trial seam: sample number, date,

test results, welder number, ambient temperature, welder temperature

and pressure, and rate of seaming. For chemical seams, the chemical

type and mixture should be recorded.

f. Field Seams. 

(1) General Requirements.

(a) The subgrade should be firm and dry prior to seaming. Due

to wet subgrade conditions, the contractor may choose to place a

sacrificial “rub sheet” under the seam to act as a barrier against

moisture. 

(b) Seam preparation is crucial to obtaining quality welds. 

Verify the areas to be seamed are clean and dry. Even morning dew can

affect the quality of seams. 

(c) Seaming should be performed when the ambient temperature is

in the allowable range as described in the installer’s QC manual. The

location where ambient temperature is measured needs to be agreed on

prior to the start of installation. Often, the ambient temperature is

defined as the temperature 150 mm (6 inches) above the geomembrane

surface.

(d) All geomembranes which have been deployed should be seamed

together by the end of the work day. Do not allow open seams to be
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3.5-7

left overnight.

(e) Verify geomembrane sheets are overlapped the minimum

specified distance (typically, 76 mm (3 inches)) prior to seaming. 

(f) Verify that seams extend to the outside edge of the sheets.

(g) Excessive waves along seams during the seaming operation

should be avoided. When this occurs, due to either the upper or lower

sheet having more slack than the other or because of thermal expansion

and contraction, it often leads to the formation of "fishmouths". 

Inspect for fishmouths in completed seams. Fishmouths should be

trimmed, laid flat and reseamed.

(h) Pay special attention to the construction of seams in the

sumps of liner systems. This is where liquids will accumulate in the

liner, therefore, it is critical that these areas are constructed

properly. 

(i) Seaming of geomembranes to be placed in an anchor trench

can be accomplished by temporarily supporting the adjacent sheets to

be seamed on a wooden support platform. This allows continuous

horizontal seams to be made out to the end of the geomembrane sheets. 

The wooden platform is removed after the seam is complete and the

geomembrane is allowed to drop into the anchor trench.

(j) Destructive and nondestructive tests can also be performed

while the seamed geomembranes are temporarily supported in the

horizontal position.

(k) Ensure that protection is provided if a generator is placed

on top of the geomembrane. Fuel for generators must be stored away

from the geomembrane. If accidently spilled on the geomembrane, it

must be immediately removed. Spill areas should be inspected for

damage and repaired if necessary.

(l) Seams around pipes and other appurtances are the most

difficult seams in a facility. Therefore, these seams should be

carefully inspected to ensure they are leak free. Ensure pipes are

long enough to allow pipe boots to be attached.

(m) The QA Representative should ensure the following

information is recorded for each seam: seam number, date, seaming

unit used, name of seamer, and any other information called for in the

specifications or QA plan. 

(2) Polyethylene Geomembrane Seams.

(a) Fusion seams. Polyethylene geomembranes should be seamed

by thermal fusion methods (double hot wedge welds) wherever possible. 

Look for the following when observing fusion welds.

& The type of geomembrane, rate of seaming, and ambient

factors such as clouds, wind, and hot sun require the

temperature setting of the wedge to vary. Depending upon

the records to be kept, one might record a number of

different temperatures. For example, the temperature of

the hot wedge, the temperature of the seaming area and the

ambient temperature. This is a site specific decision

usually determined by the specifications and the QA plan.

& At least two people are required in making hot wedge 
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3.5-8

welds: one operator and one helper.

& A leak-proof T-connection is necessary wherever

intersecting seams are to be joined together. At such

locations, the hot wedge device must be removed a short

distance (approximately 150 mm (6 inches)) from the

intersecting seam. For polyethylene geomembranes, this

short distance must be completed by extrusion fillet

seaming.

& A smooth insulating plate or heat insulating fabric should

be placed beneath hot welding devices while they are not

in use.

(b) Extrusion Seams. Extrusion welding should only be allowed

for patching and seaming around appurtenances. Look for the following

when observing the construction of extrusion welded seams.

& Heat tacking is often used to hold geomembranes in place

so that extrusion seams can be made more easily. A hot

air device is used to make tack welds.

& The surfaces of all polyethylene geomembranes should be

ground prior to extrusion welding using an electric rotary

grinder. Number 80 to 100 grit size is typically used for

grinding. All of the surface sheen in the area to be

seamed should be totally removed. 

& Grinding marks should be oriented perpendicular to the

seam direction and no marks should extend beyond the

extrudate.

& In general, grinding marks should not appear beyond 6 mm

(.25 inches) outside of where extrudate is placed. 

& The depth of the grinding marks should be no greater than

10 percent of the sheet thickness.

& Verify all of the material that has been ground from the

geomembrane is wiped or blown away from the actual seaming

zone.

& Extrusion welding should begin within 10 minutes after

grinding. The extrusion bead should be centered over the

top of the geomembrane seam.

& For HDPE geomembranes which are 1.5 mm (60 mils) or

greater in thickness, the leading edge of the upper sheet

should be beveled. The upper geomembrane must be lifted

off the lower so the lower sheet is not damaged by the

grinder.

& Extrudate thickness should be approximately equal to or

greater than the specified sheet thickness measured from

the top of the upper sheet to the top or crown of the

extrudate. Excessive squeeze-out of extrudate along the

edges of the seam is acceptable as long as it is

adequately joined to the geomembrane.

& Visual inspection of the extrudate bead should be made for

straight line alignment, height, and uniformity of surface

texture. There should be no bubbles or pock marks in the

extrudate. Such surface details on the extrudate
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3.5-9

indicates the presence of air, water or debris within the

extrudate.

& Where extrusion welds are temporarily terminated long

enough to cool, they should be ground prior to applying

new extrudate over the existing seam.

& After temporary work stoppages, the extrusion welder

should be purged of all old extrudate in the barrel. The

extrudate should not be discharged onto the surface of

previously placed geomembrane or the geomembrane subgrade.

& A smooth insulating plate or heat insulating fabric should

be placed beneath hot welding devices while they are not

in use.

(3) Non-Polyethylene Geomembrane Seams.

(a) Non-polyethylene geomembranes can be seamed by thermal

fusion or chemical methods.

(b) Seaming adhesives, solvents, or chemical cleaning agents

should not be stored on top of the geomembrane and only spillresistant containers should be used while working with these materials

on the geomembrane. 

(c) For chemical fusion and adhesive fabricated seams, testing

cannot be performed until adequate curing of the seam occurs. During

this curing time, make sure all production seaming is tracked and

documented.

(d) Accelerated oven curing of chemical and adhesive fabricated

seams is acceptable to obtain test results as soon as possible.

g. Field Sampling and Testing.

(1) Non-Destructive Leak Testing.

(a) Verify and document that field seams are tested for leaks

over their full length. The QA Representative should verify the

following is being recorded: date, seam number, test unit number (if

applicable), name of test person, test data, and outcome of testing.

(b) Pressure testing should be used to test double hot wedge

weld seams. This is done using the following procedure.

& Isolate a section of seam. No limitations are generally

placed on the length of seam that can be tested.

& Pressurize the isolated channel using a hollow needle

connected to an air pump. Typically the pressure used is

167 to 267 kPa (25 to 40 psi).

& Monitor for pressure drops over a specified period of time

(typically 5 minutes).

& If the pressure drop is less than a specified value, the

seam passes. The allowable pressure drop depends on the

initial pressure in the seam. A typical allowable

pressure drop is 20 kPa (3 psi).

& Visual observation or listening for escaping air will

often determine the location of leaks.
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3.5-10

& After the test is complete, the end of the seam which is

opposite of where the air pump is located should be cut. 

A QA Representative should be present when the seam is cut

open. Listen for escaping air to ensure the seam is

continuous over the full length tested.

(c) A vacuum box is often used for extrusion welds and other

seams where it is not possible to pressure test. The vacuum test

procedure typically consists of the following steps.

& Wet a section of seam with soapy water.

& Place the vacuum box over the seam and create a vacuum.

& View the seam through the transparent window in the box

for approximately 10 seconds. If no bubbles are evident,

then the area is considered passing.

& If bubbles are evident, mark the area for repair, perform

the repair, and repeat the vacuum test.

(d) Verify seam testing is performed as the seaming work

progresses, not at the completion of field seaming.

(e) Ensure the location, date, test number, name of test person

and results are recorded for all seam leak tests. 

(2) Destructive Field Seam Testing. Destructive testing of

seams is conducted to provide a direct evaluation of seam strength and

bonding efficiency. Destructive testing involves two types of tests: 

shear and peel tests. 

(a) Typically, one destructive test sample should be taken per

230 meters (750 feet) of field seam. Observe all production seam

sample cutting. 

(b) Do not identify sample locations to the installer prior to

seaming. Ask for additional seam tests if seams appear to be of

questionable quality.

(c) Samples are typically a minimum of 300 mm (12 inches) wide

by 1.1 m (42 inches) long with the seam centered lengthwise. 

(d) Each sample is typically cut into three equal pieces with

one piece retained by the installer, one piece given to the QA

laboratory, and the remaining piece retained by the Government for

possible testing and permanent record. Ensure that the samples going

to the QA laboratory are properly labeled and packaged as described in

the paragraph entitled “Trial Seams”.

(e) Ensure each sample is numbered and cross referenced to a

field log and also shown on the record drawings. The reason for

taking the sample should also be indicated, e.g., routine, suspicious

feature, change in sheet temperature, etc.

(f) Shear and peel tests are typically performed by both the

installer and the QA laboratory to ensure the seams have adequate

strength. Reference the paragraph entitled "Trial Seams" for a

description of the testing procedure to be used. The QA

Representative should monitor and document all destructive seam tests

performed by the geomembrane installer.
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3.5-11

(g) Compare the results of the field tests to the QA laboratory

test results to make sure they agree. Require additional testing if

there is a disagreement between the sets of test data. 

(h) The QA Representative should ensure the following

information is recorded for each seam sample tested: sample number,

date, test results, welder number, ambient temperature, welder

temperature and pressure, and rate of seaming. For chemical seams,

the chemical type and mixture should be recorded.

(i) Ensure destructive seam sample holes are repaired and

nondestructively tested for leaks the same day they are cut. 

h. Defects and Repairs.

(1) Destructive Seam Test Repairs.

(a) Seams that fail destructive seam testing may be cap

stripped by seaming an additional strip of material over the failed

seam between any two passed destructive test locations. 

(b) Alternatively, the contractor may choose to try to isolate

the weak area of the seam by retracing the seaming path to a location

a specified distance (typically, at least 3.1 m (10 feet)) on either

side of the failed seam location using the following procedure:

& At each location, samples should be taken so the

contractor can perform additional shear strength and

additional peel adhesion tests;

& If these tests pass, then the remaining seam sample

should be sent to the QA laboratory for shear strength and

peel adhesion tests;

& If these laboratory tests pass the specified strength

criteria, then the seam should be cap stripped between

passing destructive tests;

& After cap stripping, the entire cap stripped seam should

be tested for leaks; and

& Documentation of all failed destructive seams should be

recorded on the as-built drawings.

(2) Patches.

(a) Patching and cap stripping should be used to repair large

holes, tears, and locations where destructive seam samples were taken. 

Ensure patches have rounded corners and extend a minimum of 15.3 cm (6

inches) beyond the edge of defects. 

(b) Minor localized flaws such as pin holes can be repaired by

spot welding.

(c) Ensure repairs are non-destructively tested for leaks. 

(d) Verify all repairs are documented in the daily reports and

recorded on the as-built drawings. 

i. Penetrations and Connections.

(1) Factory fabricated boots should be used wherever possible.
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3.5-12

Boots are prefabricated connections which allow a water-tight seal to

be constructed at pipe penetrations. 

(2) The skirt of the pipe boot which flares away from the pipe

penetration should typically have at least 300 mm (12 inches) of

geomembrane on all sides of the pipe.

(3) Verify non-destructive leak testing is performed on the

seams which attach the skirt to the geomembrane. 

(4) A stainless steel clamp is generally used to attach the

boots to pipes. A cushion of compressible material should be placed

between the clamp and the boot.

j. Covering. Refer to Chapter 3.9 Cover Soil Layer for

additional information on cover soil placement.

(1) Pushing the cover soil across the geomembrane surface can

cause large wrinkles to develop. Require the contractor to modify the

placement procedure if the wrinkles become so large that they fold

over and crease the geomembrane.

(2) Periodically inspect the surface of the geomembrane for

bulges which may be an indication that gas or water is collecting

beneath the geomembrane. Stop construction and notify the design

district if this situation occurs. 
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3.6-i

CHAPTER 3.6

DRAINAGE LAYER

Paragraph Page

3.6-1 GENERAL 3.6-1

a. Preconstruction 3.6-1

 Submittals

b. Delivery, Storage, 3.6-1

 and Handling

3.6-2 PRODUCTS 3.6-2

Geonet 3.6-2

3.6-3 EXECUTION 3.6-2

a. Installation 3.6-2

b. Repairs 3.6-3

c. Covering 3.6-3

3.6-4 GRANULAR DRAINAGE LAYER 3.6-3

a. Preconstruction Submittals 3.6-3

 b. Construction Submittals 3.6-4

c. Granular Drainage Layer 3.6-4

 Material

d. Installation 3.6-4

e. Protection 3.6-4
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3.6-1

CHAPTER 3.6 DRAINAGE LAYER

3.6-1. GENERAL. Drainage layers are constructed with either geonets

or coarse grained granular soils. A geonet consists of a set of

parallel plastic ribs positioned in layers such that liquid or gas can

be transmitted within the void spaces between the ribs. Geonets are

often used instead of soils for drainage layers because they have a

higher flow capacity, require less space, and are easier to construct. 

Most geonets are manufactured using polyethylene and are typically 5.0

to 8.0 mm (0.20 to 0.30 inches) in thickness. The large voids within

the geonet must be protected from clogging. Therefore, geonets always

function with either geomembranes and/or geotextiles on their two

planar surfaces. Whenever the geonet comes supplied with a geotextile

attached to one or both of its surfaces, it is called a geocomposite. 

The geotextiles are bonded to the geonet by heat fusing or by use of

an adhesive. 

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements. 

(1) Manufacturer's QC test results. 

(2) If a geotextile is attached to one or both sides of the

geonet, bond adhesion test results should be submitted.

(3) Interface friction test results. 

(4) Geonet sample with any attached geotextiles (if required). 

b. Delivery, Storage, and Handling.

(1) A QA Representative should be present during delivery and

unloading of the geonet to inspect for damage.

(2) Verify that rolls are labeled with the manufacturers name,

product identification, lot number, roll number, roll dimensions, and

date manufactured.

(3) The QA Representative should record roll numbers, date

delivered, name of manufacturer, and product type. This data is used

to verify manufacturer’s QC data sheets have been submitted for the

rolls being delivered. 

(4) Geonet rolls should be handled and unloaded with load

carrying straps, a fork lift with a stinger bar, or an axial bar

assembly should be used.

(5) Do not allow rolls to be dragged, lifted by one end, or

dropped to the ground.

(6) Ensure the geonet is kept free of dirt, dust, mud, or any

other foreign materials. Ideally, geonet should not be stored

directly on the ground since they do not arrive at the job site with a

protective plastic cover. 

(7) Temporary storage at the job site should be in a flat

smooth area where standing water cannot accumulate. A geomembrane or

ground cloth should be placed under the geonet if they are stored on

soil for longer than a month. This will prevent weeds from growing
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3.6-2

into the lower rolls of the geonet. If weeds do grow in the geonet

during storage, ensure they are removed when the geonet is deployed.

(8) Geocomposite should be stored with an opaque cover over it

to protect the geotextile. 

(9) Ensure rolls are not stacked so high that the cores are

crushed or the geonet is damaged.

3.6-2. PRODUCTS.

Geonet. 

(1) Cross check the roll numbers of the geonet delivered to the

site against the roll numbers on the manufacturer’s QC test data

submittals to ensure they match. Ensure the geonet meets the property

requirements outlined in the specifications for material type and

physical properties.

(2) Check the transmissivity test results to make sure the

tests were run using the specified normal stress, gradient, and

boundary conditions.

(3) Inspect geotextiles which have been heat bonded to geonets

to make sure the geotextiles have not been damaged or thinned by the

bonding process.

(4) If a geotextile is attached to one or both sides of the

geonet by adhesives, check to make sure excessive adhesive has not

filled the void spaces in the geonet.

3.6-3. EXECUTION.

a. Installation.

(1) A QA Representative should be present at all times during

geonet installation.

(2) Prior to placement of the geonet, verify the subgrade is

smooth and will not damage or clog the geonet.

(3) Do not allow geocomposite to be dragged across the surface

of a textured geomembrane. This can result in damage to the

geocomposite.

(4) The geonet should be unrolled down slope keeping the net in

slight tension to minimize wrinkles and folds.

(5) Adequate ballast (e.g. sandbags) should be placed to

prevent uplift by wind.

(6) Overlaps and Fasteners.

(a) Ensure roll ends and edges are overlapped the specified

distance. Typically, roll edges are overlapped a minimum of 75 mm (4

inches) and roll ends are overlapped a minimum of 160 mm (6 inches). 

(b) Ensure plastic fasteners are used to join adjacent rolls. 

Metallic fasteners should not be allowed because they can puncture

geomembranes. 
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3.6-3

(c) Ensure fasteners are placed at the specified spacings. 

Fasteners are typically spaced a maximum of 1.5 m (5 feet) apart along

down slope roll overlaps and a maximum of 150 mm (0.5 feet) apart

along cross slope roll overlaps. 

(d) Fasteners should be of contrasting color from the geonet to

facilitate visual inspection.

 (e) Geonets should never be welded to geomembranes.

(f) If horizontal overlaps are required on side slopes, they

should be staggered for adjacent rolls.

(g) When more than one layer of geonet is required, verify that

end and edge overlaps are staggered so that joints do not lie above

one another. 

(h) Stacked geonet layers should always be laid in the same

direction to maintain transmissivity requirements. However, they

should be laid on top of each other such that interlocking does not

occur. 

(i) Do not allow geocomposites to be dragged across the surface

of a textured geomembrane because the geotextile will be damaged.

(j) No personnel working on the geonet should smoke or wear

shoes which could damage the geosynthetics.

(k) Verify that any area requiring repair is clearly marked.

b. Repairs.

(1) Holes or tears in the geonet are typically repaired by

placing a patch of geonet extending a minimum of 610 mm (2 feet)

beyond the edges of the hole or tear. 

(2) Fasteners are typically spaced every 150 mm (6 inches)

around patches.

(3) If a tear is present across more than 50 percent of the

width of the geonet on side slopes, require the entire length of

geonet to be removed and replaced.

c. Covering. Refer to Chapter 3.9 Cover Soil Layer for

additional information on cover soil placement. 

3.6-4. GRANULAR DRAINAGE LAYER. Granular drainage layers are

generally composed of sand or gravel and usually have a minimum

thickness of 300 mm (12 inches). If the drainage material will be

placed adjacent to a geomembrane, the maximum particle size is

typically required to be no greater than 12.5 mm (0.5 inches). The

drainage layer should generally not be compacted since this may

increase the percent fines, decrease the hydraulic conductivity, and

damage underlying geosynthetics. A natural or geotextile filter is

often provided on top of the granular drainage layer to prevent

clogging.

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements. 
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3.6-4

(1) Materials Handling Plan which describes the processing and

placement of the granular drainage layer.

(2) Borrow Source Assessment Report. At a minimum, one set of

borrow assessment tests should be performed for each borrow source. A

set of borrow source assessment tests generally consists of gradation,

hydraulic conductivity, and possibly carbonate content. 

(3) Samples of granular drainage material (if required).

b. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Borrow classification test results. 

(2) Hydraulic conductivity test results.

c. Granular Drainage Layer Material.

(1) Check the properties of the drainage material (grain size

distribution and hydraulic conductivity) being submitted against the

requirements listed in the specifications. During construction,

require additional testing if the properties of the drainage material

appear to be changing.

(2) Hydraulic Conductivity Test Results. Consider requiring

the contractor to perform additional testing prior to placement if

pre-construction test results just barely meet the hydraulic

conductivity requirements stated in the specifications. The

reproducibility of hydraulic conductivity tests is not good,

therefore, a material may just barely meet the hydraulic conductivity

standard in one test but fail to meet minimum requirements in another

test. Also, additional fines will be generated every time a drainage

material is handled. The additional fines can significantly decrease

hydraulic conductivity.

(3) Verify that oversize and angular material which could

damage geosynthetic layers has been removed prior to placement.

d. Installation.

(1) Verify drainage material is being placed to the lines and

grades shown on the drawings. 

(2) Granular materials placed on top of geosynthetic components

on side slopes should be placed from the bottom of the slope up.

(3) When granular drainage material is placed on top of

geosynthetics and spread with a dozer, the sand or gravel should be

lifted and tumbled forward to minimize shear forces on the underlying

geosynthetics.

(4) Inspect the placement operation by observing the front of

the working face as the materials are being spread to ensure that the

underlying geosynthetics are not being damaged.

e. Protection.

(1) Verify that wind-borne and water-borne fines do not

contaminate the drainage layer after placement.
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3.6-5

(2) Watch for ponding on top of the drainage layer. This may

indicate fines have contaminated the drainage layer.

(3) Areas of erosion should be repaired and grades

reestablished.
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3.7-i

CHAPTER 3.7

GEOTEXTILE

Paragraph Page

3.7-1 GENERAL 3.7-1

a. Preconstruction 3.7-1

 Submittals

b. Construction Submittals 3.7-1

c. Delivery, Storage, 3.7-1

 and Handling

3.7-2 PRODUCTS 3.7-2

Geotextile 3.7-2

3.7-3 EXECUTION 3.7-2

a. Subgrade Preparation 3.7-2

b. Installation 3.7-2

c. Protection 3.7-3

d. Seaming 3.7-3

e. Repairs 3.7-4

f. Covering 3.7-4
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3.7-1

CHAPTER 3.7 GEOTEXTILE

3.7-1. GENERAL. Geotextiles consist of woven or nonwoven textile

sheets supplied to the job site in large rolls. The majority of

geotextiles used in landfill systems are made from either

polypropylene or polyester. When ready for placement, the rolls are

removed from their protective covering, properly positioned and

unrolled over the subgrade. Geotextiles can be used for separation of

materials, filtration, reinforcement, and erosion control. This

section will focus on geotextiles used for separation and filtration. 

A separation/filtration layer is normally required between a soil

layer and an underlying drainage layer. The separation/filtration

layer ensures consistent drainage properties by preventing migration

of fine grained soil particles into the void spaces of the drainage

layer. 

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

 (1) Manufacturer's QC test results. 

(2) For needle punched geotextiles, the manufacturer should

certify that the geotextile has been continuously inspected using

permanent in-line full-width metal detectors and does not contain any

needles which could damage other geosynthetic layers. 

(3) Proposed thread type for sewn seams along with data sheets

showing the physical properties of the thread. The thread typically

is made from polypropylene, polyester, nylon, or a proprietary

material. 

(4) Geotextile samples (if required). b. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

Seam strength test results (if required).

c. Delivery, Storage and Handling.

(1) A QA Representative should be present during delivery and

unloading of the geotextile to inspect for damage. 

(2) Verify that rolls are labeled with the manufacturers name,

product identification, lot number, roll number, roll dimensions, and

date manufactured. 

(3) The QA Representative should record roll numbers, date

delivered, name of manufacturer, and product type. This data is used

to verify manufacturer’s QC data sheets have been submitted for the

rolls being delivered.

(4) Verify each geotextile roll is wrapped around a central

core and covered with an opaque, waterproof, protective covering. 

Require that tears in the packaging be repaired using tape and plastic

sheeting to restore a waterproof protective barrier around the

geotextile.
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3.7-2

(5) Rolls should be immediately rewrapped after QA/QC samples

have been collected.

(6) Geotextile rolls should be handled and unloaded with load

carrying straps, a fork lift with a stinger bar, or an axial bar

assembly should be used.

(7) Do not allow rolls to be dragged, lifted by one end, or

dropped to the ground.

 (8) Field storage should not be in areas where water can

accumulate. Rolls of geotextile should either be elevated off the

ground or placed on a sacrificial sheet of plastic. Saturated

geotextile if difficult to handle.

(9) Rolls should not be stacked so high that the cores are

crushed or the geotextile is damaged.

3.7-2. PRODUCTS. 

Geotextile.

(1) Cross check the roll numbers of the geotextile delivered to

the site against the roll numbers on the manufacturer’s QC test data

submittals to ensure they match. Ensure the geotextile meets the

property requirements outlined in the specifications for material type

and physical properties.

(2) More than one type of geotextile is often required on a

job, verify the correct geotextile type is being used for each

component of the job.

3.7-3. EXECUTION.

a. Subgrade Preparation. Inspect the surface underlying the

geotextile prior to installation. It should be smooth and free of

ruts or protrusions which are greater than the specified requirements

(typically 25 mm (1 inch)). Verify the lines and grades of the

subgrade are correct prior to geotextile placement. 

b. Installation.

(1) A QA Representative should be present at all times during

geotextile placement.

(2) Geotextile should be laid smooth so that it is free of

tensile stresses, folds, and wrinkles. 

(3) On slopes greater than 5 horizontal on 1 vertical, the

geotextile should be unrolled parallel to the direction of maximum

slope. 

(4) Do not allow geotextile to be dragged across the surface of

a textured geomembrane. This will result in damage to the geotextile.

(5) Inspect the geotextile for damage if it has been placed on

a textured geomembrane surface and then removed from the membrane. 

(6) No personnel working on the geotextile should smoke or wear
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3.7-3

shoes which could damage the geosynthetics.

(7) Any area requiring repair should be clearly marked.

c. Protection.

(1) Ensure that geotextile is protected during installation

from clogging, tears, and other damage. 

(2) Ensure ballast (typically sand bags) is used to prevent

wind damage to deployed geotextile. 

(3) Check the specifications to determine the maximum allowable

exposure time for the deployed geotextile. In general, geotextiles

made from polypropylene should not be left uncovered for more than 14

days during installation. Geotextiles made from polyester may be left

uncovered for up to 28 days. If the allowable exposure period has

been exceeded, one method of determining if the geotextiles have been

damaged is to require the contractor to perform QC tests to verify the

physical properties of the textile have not diminished due to

exposure. 

(4) The use of staples or pins to hold geotextiles in place

should not be allowed in applications where the geotextile will be

located adjacent to other geosynthetics.

d. Seaming. Review the drawings and specifications to

determine if overlap, sewn, or thermally bonded seams are required. 

Geotextile seams are typically overlapped in flat areas such as

landfill liner bottoms. On landfill side slopes, the geotextiles are

generally sewn. 

(1) Overlap Seams.

(a) Ensure overlaps meet the minimum specified requirements. 

Typically, geotextile edges are overlapped a minimum of 300 to 600 mm

(12 to 24 inches). If the geotextile is being placed on a soft

subgrade, the overlap distance may need to be greater. 

(b) Where it is required that seams be oriented across the

slope, the upper layer should be lapped over the lower layer. 

(c) Inspect for openings in the seams during placement of cover

soil. 

(2) Sewn Seams. If sewn seams are used, check the

specifications to determine if trial seams are required. 

(a) Ensure sewn seams are continuous. Spot sewing is generally

not allowed. 

(b) Verify seams are sewn at the locations shown on the

drawings. 

(c) Determine if the specifications require a specific type of

stitch be used for sewn seams.

(d) Verify that the minimum distance from the geotextile edge

to the stitch line nearest to that edge is as recommended by the

manufacturer. 
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3.7-4

(e) The thread at the end of each seam run should be tied off

to prevent unraveling. 

(f) Inspect for skipped stitches or discontinuities. These

areas should be sewn with an extra line of stitching with 450 mm (18

inches) of overlap on each side. 

(g) Check the specifications to determine if the sewn seams

must be tested for strength.

e. Repairs.

(1) Require geotextile damaged during installation to be

repaired by placing a patch of the same type of geotextile over the

damaged area. Patches generally extend a minimum of 300 mm (12

inches) beyond the edge of the damage or defect. 

(2) Patches should be continuously fastened using a hand or

machine sewn seam or other approved method. The machine direction of

the patch should be aligned with the geotextile being repaired. 

Machine direction is defined as the long direction of the geotextile.

f. Covering. Refer to Chapter 3.9 Cover Soil Layer for

information on cover soil placement.
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3.8-i

CHAPTER 3.8

PIPE AND APPURTENANCES

Paragraph Page

3.8-1 GENERAL 3.8-1

a. Preconstruction 3.8-1

 Submittals

b. Construction Submittals 3.8-1

c. Delivery, Storage, and 3.8-1

 Handling

3.8-2 PRODUCTS 3.8-2

a. General 3.8-2

b. PVC Pipe 3.8-2

c. HDPE Smooth Wall Pipe 3.8-2

d. HDPE Corrugated Pipe 3.8-2

3.8-3 EXECUTION 3.8-2

a. Placement 3.8-3

b. Sumps, Manholes, and 3.8-3

 Risers

c. Double Wall 3.8-4

 Containment Pipe
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3.8-1

CHAPTER 3.8 PIPE AND APPURTENANCES

3.8-1. GENERAL. This section will focus on the installation of

plastic pipe. PVC and HDPE are the two most common types of plastic

pipe used at hazardous waste sites. Some uses of plastic pipe at

hazardous waste sites include:

& drainage layers in landfill covers and liners;

& ground water monitoring, extraction, and recharge wells;

& ground water extraction and recharge trenches; and

& soil vapor extraction, bioventing and air sparging

systems.

Additional information on construction of pipe systems is available in

Volume 1 of the Quality Assurance Representative’s Guide, in the

chapter titled “Underground Pipe Systems”. 

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Manufacturer’s pipe installation recommendations.

(2) Manufacturer’s QC manual and QC test results.

(3) Samples of pipe (if required).

(4) Samples of pipe bedding material (if required).

(5) Samples of warning tape used to mark pipe locations (if

used).

(6) Samples of backfill material (if required).

(7) If required, the QA Representative should see that QA test

samples are obtained upon delivery of the pipe. 

(a) Ensure that the pipe is identified according to its proper

ASTM standard.

(b) Ensure that QA test results are approved prior to pipe

deployment.

b. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

Results of leak and/or pressure tests (if required).

c. Delivery, Storage, and Handling. Both PVC and HDPE pipe are

manufactured in lengths of approximately 6.1 m (20 ft) with varying

wall thicknesses and configurations. They are placed on wooden

pallets and bundled together with plastic straps for bulk handling and

shipment. 

(1) The QA Representative should be present during delivery and

unloading of pipe to inspect for damage. 
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3.8-2

(2) The QA Representative should record applicable pipe

numbers, date delivered, name of manufacturer, and product type. This

data is used to verify manufacturers QC data sheets have been

submitted for the pipe being delivered.

(3) Steel cables and chains should not be used to handle pipe.

(4) Ensure that field storage is in an area where water can not

accumulate. The pallets of pipe should be placed on level ground and

oriented so the pipes do not pond water.

(5) Pallets of pipe should not be stacked more than three high. 

They should also be protected from direct sunlight if recommended by 

the manufacturer.

(6) Gaskets for bell and spigot pipe connections should not be

stored in direct sunlight.

3.8-2. PRODUCTS.

a. General.

(1) Ensure the correct material type, strength, and diameter of

pipe has been delivered to the job site.

(2) Verify the size, number and location of pipe perforations

are as specified.

(3) Pipe with external gouges deeper than 10 percent of the

wall thickness should be discarded or repaired before used. 

(4) Out-of-round pipe which cannot be properly joined together

should be repaired or rejected.

b. PVC Pipe. PVC pipe typically consists of resin, fillers,

carbon black, pigment, and additives. PVC pipe does not contain any

liquid plasticizers.

(1) Pipe tolerances and properties must meet the applicable

standards required by the plans and specifications. ASTM D-1785 or

ASTM D-2241 are often referenced when specifying PVC pipe.

(2) PVC pipe fittings are generally constructed in accordance

with ASTM D-3034. The pipes are joined by couplings or bell and

spigot ends.

c. HDPE Smooth Wall Pipe. HDPE pipe material consists of

resin, carbon black, and additives. The pipes are generally joined

together using butt-end fusion welds. Other joining methods such as

bell and spigot, male-to-female and threading are also used.

d. HDPE Corrugated Pipe. Corrugated HDPE pipe is also called

“profiled” pipe. This type of pipe can be perforated or slotted and

the inside can be either smooth or corrugated depending on the sitespecific requirements. The pipes should be joined together by

couplings made by the same manufacturer as the pipe itself. This is

important since the couplings are generally not interchangeable among

the different manufacturer’s products.

3.8-3. EXECUTION.
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3.8-3

a. Placement. This section focuses on placement of pipe in

trenches and landfill drainage layers.

(1) If pipe is to be placed above a geomembrane, check the

specifications to see if a bedding layer should be placed between the

pipe and membrane. 

(2) Check compaction requirements for any bedding layers

located around the pipe. The density of the material beneath,

adjacent, and immediately above plastic pipe greatly affects its loadcarry capacity. 

(3) Pipe should be carried to the place of installation and not

dragged.

(4) Inspect pipe carefully before it is placed. Reject any

defective or damaged pipe.

(5) Pipe laying should proceed upgrade, beginning at the lower

end of the pipeline. 

(6) Ensure that pipe is not laid when trench conditions or

weather is unsuitable. Under no circumstances should pipe be

installed if standing water is present. Ensure the contractor has

dewatered the trench prior to pipe placement.

(7) Ensure that pipe is placed at the lines and grades 

indicated in the plans and specifications.

(8) Perforated pipe should be installed with the perforations

facing down unless otherwise specified.

(9) Pipe fittings or joints should be installed according to

requirements stated in the specifications. Ensure pipe and fittings

are clean of all dirt, debris, oil or any other contaminant which may

inhibit the construction of a sound joint. 

(10) Inspect and approve all in-place pipe before allowing

backfill placement. Ensure all required leak tests are performed

prior to backfilling.

b. Sumps, Manholes and Risers. A piping system may be

specified as part of the primary or secondary leachate collection

system of a landfill liner. Pipes used in landfill liners are usually

made of high density polyethylene (HDPE). The purpose of the piping

system is to rapidly remove leachate from the liner. Perforated

feeder pipes are usually designed to flow to a central trunk line. 

The trunk line may or may not be perforated, depending on sitespecific design requirements. The trunk line flows by gravity to a

low point in the liner system referred to as a sump. The sump is

typically filled with coarse granular material which provides storage

for leachate. The leachate is periodically removed from the sump

through a riser pipe using a submersible pump. Sumps can also consist

of prefabricated vertical risers with a manhole extension rising

through the waste and final cover. 

(1) Sumps are very labor intensive and difficult to construct. 

Careful visual inspection is required in sump areas since these are

the low points in the liner system where water will collect. 

(2) Check compaction requirements for the subgrade material

located beneath the sump. 
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3.8-4

(3) Carefully inspect placement of sump stone because its large

diameter can easily damage underlying geosynthetics. The drop height

of the first lift of sump stone should be small enough that underlying

geosynthtics are not damaged (typically 300 mm (12 inches) or less). 

(4) Check the specifications for pipe perforation requirements. 

Sump riser pipes for primary and secondary leachate removal are

generally not perforated, except for the lowest section of pipe which

allows leachate to enter the pipe.

(5) Carefully inspect riser pipe joints for primary and

secondary leachate removal since neither destructive nor

nondestructive tests can usually be performed. 

(6) Verify that test operation of pumps, level alarms, valves,

switches, and controls have been performed in accordance with

manufacturer’s recommendations.

c. Double Wall Containment Pipe. Double wall containment pipe

is often required for carrying hazardous liquids outside the landfill

liner system. 

(1) Check the specifications to determine if and where double

wall containment pipe is required. 

(2) Check the specifications for special testing requirements

for double wall containment pipe.

(3) Some double wall pipe requires the use of potentially

hazardous glue to make pipe connections. Manufacturer’s recommended

safety precautions should be followed if this is the case.

(4) If piping is glued, ensure the glue is allowed to set

within the recommended temperature range.

(5) If piping is glued, ensure there is adequate ventilation

since the glue may be both hazardous and flammable.

(6) A double wall pipe manufacturer’s representative should

generally be on site at the beginning of pipe installation for

training, and periodically during installation to ensure correct

procedures are used.

(7) If an electrical leak detection system is used, it is

critical to ensure ends of the containment piping are sealed overnight

and when work is not ongoing. Dirt or water which enters the annular

space will interfere with the leak detection cable and could cause

operational problems.

(8) Inner (carrier) pipes should be hydrostatically tested and

outer (containment) pipes should be pneumatically tested at the

specified pressures.

(9) Frequently, double wall pipe is sloped so that if there is

a leak in the carrier pipe, the fluid flows by gravity in the

containment pipe to a sump or tank. 
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3.9-i

CHAPTER 3.9

COVER SOIL LAYER

Paragraph Page

3.9-1 GENERAL 3.9-1

a. Equipment 3.9-1

b. Preconstruction 3.9-2

 Submittals

c. Construction Submittals 3.9-2

d. Weather Limitations 3.9.2

3.9-2 PRODUCTS 3.9-2

Cover Soil 3.9-2

3.9-3 EXECUTION 3.9-2

a. Installation 3.9-2

b. Compaction 3.9-4

c. Repairs 3.9-4

d. Protection 3.9-4
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3.9-1

CHAPTER 3.9 COVER SOIL LAYER

3.9-1. GENERAL. This chapter lists QA responsibilities during

placement of cover soil above geosynthetics. Placement of cover soil

is a critical step since the underlying geosynthetic materials are

relatively thin layers which can be easily damaged. In a liner

system, the cover soil will typically consist of a drainage layer or a

clay barrier layer. Cover soil placed above geosynthetic layers in a

landfill cover is commonly referred to as select fill. In

addition to protection of geosynthetics, the select fill layer also

protects the low-permeability clay layer from freezing temperatures

and desiccation. The select fill layer in a landfill cover should be

composed of soil that is capable of sustaining a vegetative cover

throughout dry periods. The select fill also provides water holding

capacity to slow down rainfall infiltration to the drainage layer. 

The type of soil used for select fill is a site specific

decision. Typically, select fill will consist of medium-textured

soils for both function and constructibility. Cohesionless silts and

sands are undesirable because these soils have low water retention

capacity and nutrients are easily leached from them. However, high

plasticity clays can damage underlying geosynthetics during placement. 

The best materials are usually cohesive but not highly plastic. 

Consult the specifications for the soil type that has been deemed

“suitable” by the designer.

The maximum particle size specified for select fill will

typically range from 12.5 to 25 mm (0.5 to 1 inch) depending on the

type of geosynthetics present beneath the select fill. The use of

angular material should also be avoided because of increased potential

for damaging geosynthetics. 

The select fill layer (including topsoil) should generally be a

minimum of 600 mm (24 inches) thick or equal to the maximum frost

depth, whichever is greater. 

a. Equipment. Verify that the equipment used to place the

cover soil is in accordance with the specifications. Contact the

designer if equipment requirements for cover soil placement are not

discussed in the specifications. The following paragraphs provide

general guidance on equipment requirements.

(1) Equipment should not be allowed to travel directly on top

of geosynthtics. This includes cars and light trucks. 

(2) Check the specifications to see if all terrain vehicles

(ATV) with low ground pressure tires can be operated on top of the

geosynthetics. If ATVs are allowed to operate on top of the

geosynthetics, they should move at a slow rate of speed, travel in

straight lines or large arcs, not start or brake abruptly, and not

turn sharply. Refueling should be performed outside the limits of the

liner or cover system. 

(3) Tracked equipment with a ground pressure of less than 35

kPa (5 psi) should be used to spread the first lift of cover soil. 

(4) The required cover soil thickness needed to allow safe

operation of full scale construction equipment is site specific and

depends on the type of geosynthetics being covered, the cover soil

type, and the subgrade. Contact the design engineer if the

specifications do not indicate the minimum thickness of the cover

soil layer prior to allowing operation of full scale construction

equipment. 
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3.9-2

b. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Borrow Source Assessment Report for the cover soil. 

(2) Chemical contamination test results to verify the borrow is

not contaminated.

c. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Borrow source classification test results.

(2) In-place moisture content and density test results.

d. Weather Limitations.

(1) In general, backfilling in warm climates or during summer

months should be performed during the coolest part of the day to

minimize wrinkles in geomembranes. 

(2) In extreme cases, of excessively high temperatures,

backfilling may need to be performed during non-typical work hours,

e.g., sunrise to 10:00 AM or 5:00 PM to sunset.

(3) If cover soil placement is performed at night, ensure the

contractor is using adequate lighting to safely work. 

3.9-2. PRODUCTS. 

Cover Soil. Verify cover soil borrow source assessment testing

has been performed. Ensure the proposed cover soil meets the

specified requirements for grain size distribution, Atterberg limits,

maximum particle size, and all other physical properties specified.

(1) Periodic classification testing should be performed on the

borrow as it is excavated during construction. Check borrow test

results (sieve analysis and Atterberg limits) to verify that the

material meets the specified requirements. Require additional

classification testing if the properties of the borrow source appear

to be changing.

(2) Perform daily inspections of the cover soil to see if there

are visible changes in the properties of the borrow. Carefully

inspect for oversize particles.

3.9-3. EXECUTION.

a. Installation.

(1) A QA Representative should be present at all times during

backfilling over the geosynthetics. Check the specifications to

determine the maximum allowable exposure time for the deployed

geosynthetics prior to covering. 

(2) Ensure placement of cover soil proceeds from a stable

working area adjacent to the deployed geosynthetic material and

gradually progresses outward. For slopes, cover soil should be 
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3.9-3

placed by starting at the toe and working up the slope.

(3) Cover soil should be pushed forward in an upward tumbling

motion using a bulldozer or front end loader. 

(4) Cover soil should not be dumped or dropped directly onto

the underlying geosynthetic material from a height greater than 1

meter (3 feet).

(5) The contractor should be allowed to place access routes

over the geosynthetics to speed up cover soil placement. The access

routes will allow use of larger construction equipment to carry cover

soil out onto the geosynthetic layers. Cover soil thickness for

access routes will generally be a minimum of 900 mm (3 feet). 

(a) Tracks and wheels of full-scale construction equipment must

remain on the access routes at all times.

(b) Inspect access routes daily to see if thinning of the cover

soil is occurring. The contractor should be required to repair any

areas of the access route which are thinning. 

(6) Verify that the cover soil lift thicknesses are in 

accordance with the specifications. Typically, the first lift of

cover soil is a minimum 200-mm (8-inches) to 300-mm (12-inches) in

thickness.

(7) Do not allow large stockpiles of cover soil to be placed on

the underlying geosynthetic materials.

(8) Carefully inspect placement and compaction of soil placed

above geosynthetic layers. Look for slippage of the compaction

equipment on slopes. This can cause damage to the geosynthetics. 

(9) Look for thin areas of cover soil which could allow the

geosynthetics to be punctured or torn by construction equipment.

(10) Do not allow compaction equipment to be operated at speeds

exceeding specified limits (generally 2.2 meters per second (5.0 miles

per hour)).

(11) Watch for construction equipment braking suddenly while on

top of the cover soil.

(12) Do not allow wrinkles in the geosynthetic layers which

fold over onto themselves. To help prevent wrinkles, fingers of

backfill are sometimes pushed out over the geosynthetics with

controlled amounts of geosynthetic slack between the fingers. 

(13) Penetrations.

(a) Verify that soil placed around penetrations does not

contain voids and is adequately compacted. 

(b) Inspect pipes which penetrate the cover soil layer for

damage due to compaction equipment. 

(14) Verify the cover soil layer is placed to the lines and

grades shown on the drawings.

(15) Verify the final lines and grades of the cover soil layer

are correct.
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3.9-4

b. Compaction. Both method and performance specifications have

been used to place cover soil layers. Compaction requirements are

usually waived for the first lift of cover soil placed above

geosynthetic layers. 

(1) Method Specification.

(a) Verify the correct size and type of equipment is being used

to compact the cover soil layer. 

(b) Periodically check that the contractor is making the

required number of passes to compact all areas of the cover soil

layer. 

(2) Performance Specification. Verify the cover soil is placed

and compacted within the specified moisture content and density

ranges. Verify moisture content and density tests are performed using

specified test procedures on each lift of cover soil. Refer to

Chapter 3.3 Low Permeability Clay Layer for a description of moisture

and density testing procedures.

c. Repairs. If the cover soil layer does not conform to the

specifications, the first step is to define the extent of the area

requiring repair.

(1) Require the contractor to repair the lift of cover soil out

to the limits defined by passing QC or QA tests.

(2) Do not allow the contractor to guess at the extent of the

area that requires repair. Additional tests are often required to

define the area requiring repair.

(3) After repairs have been made, the repaired areas should be

tested at the same frequency as required for the rest of the project.

d. Protection.

(1) Require excess moisture to be removed from the surface of

the cover soil layer prior to placement of additional fill.

(2) Look for areas of erosion after each rainfall. Also look

for tire ruts and other thin areas in the cover soil layer. Require

the contractor to repair these damaged areas and reestablish grades. 

(3) Do not allow the placement of stockpiles on top of the

completed cover soil layer.
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3.10-i

CHAPTER 3.10

VEGETATIVE COVER LAYER AND EROSION CONTROL

Paragraph Page

3.10-1 GENERAL 3.10-1

a. Equipment 3.10-1

b. Preconstruction Submittals 3.10-1

3.10-2 SEEDING AND TURF PROTECTION 3.10-1

a. Seeding Times and 3.10-1

 Conditions

b. Site Preparation 3.10-1

c. Seeding 3.10-2

d. Protection and 3.10-2

 Maintenance of Turfed Areas

3.10-3 SURFACE DRAINAGE/EROSION CONTROL 3.10-2

a. Benches and Channels 3.10-2

b. Gabions 3.10-3

c. Grout Bags 3.10-4

d. Sedimentation Basins 3.10-4

e. Silt Fences 3.10-4

f. Hay Bales 3.10-5

g. Erosion Control Blankets 3.10-5
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3.10-1

CHAPTER 3.10 VEGETATIVE COVER LAYER AND EROSION CONTROL

3.10-1. GENERAL. Vegetative cover plays a key role in controlling

erosion by shielding the topsoil from precipitation, holding soil

particles together, and reducing the velocity of runoff. Welldeveloped vegetation also consumes subsurface water between rainfall

events through evapotranspiration. For landfill cover applications,

vegetation should be chosen based on the following criteria:

& Locally adapted, perennial plants resistant to droughts,

temperature extremes, and other local climatological

extremes;

& Root systems which do not disrupt the infiltration layer

and create pathways for percolation;

& Ability to thrive with a minimum of nutrient additions;

& High enough plant density to minimize soil erosion; and

& Low mowing and maintenance requirements.

a. Equipment. Check the specifications to determine if there

are any requirements for pesticide application equipment, seeding

equipment, or mulching equipment. Additional information is available

in Volume 1 of the Quality Assurance Representative’s Guide, in the

chapter titled “Establishing Grass and Plant Material”.

b. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Pesticides application plan including manufacturer's

information discussing physical characteristics and application

instructions for pesticides.

(2) Seed analysis.

(3) Lime analysis.

(4) Fertilizer analysis.

(5) Pesticide analysis.

(6) Soil tests for topsoil. Tests may include pH, organic

content, particle size, nutrient analysis, and mechanical analysis.

3.10-2. SEEDING AND TURF PROTECTION.

a. Seeding Times and Conditions. 

(1) Ensure that specified planting periods are adhered to. 

(2) Work should be stopped if unsatisfactory conditions exist

for planting. Examples of unsatisfactory conditions include excessive

moisture and drought. 

b. Site Preparation. 
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3.10-2

(1) Ensure that finished grades are completed prior to 

planting. Finished grades should be free of stones and debris and

should be protected from vehicles and erosion. 

(2) Seeded surfaces should be graded to transition smoothly to

areas undisturbed by construction.

(3) Soil amendments such as lime and fertilizer should be

applied at rates determined by topsoil analysis or as recommended in

the specifications. Lime and fertilizer are often incorporated as

part of the tillage operation.

c. Seeding.

(1) Immediately prior to the start of seeding operations,

ensure that the equipment to be used is calibrated correctly.

(2) Seeding is often performed using two passes with each pass

off-set 90 degrees from the other. Each pass should apply seed at

half the rate specified.

(3) Ensure mulching is performed the same day as seeding. 

Check the specifications to see if mulch should be disced into the

soil or if hydromulch should be used.

(4) Pesticides should be applied by a state-certified

applicator (where applicable). 

d. Protection and Maintenance of Turfed Areas.

(1) Ensure that the area is protected against traffic

immediately after mulching operations have been completed. 

(2) The turf establishment period should be stated in the

specifications. Contact the designer if it is not.

(3) The definition of a satisfactory stand of turf should be

stated in the specifications. Contact the designer if it is not.

(4) Ensure that the contractor performs maintenance of the

turfed areas, including eradicating weeds, protecting embankments and

ditches from erosion, maintaining erosion control materials,

protecting turfed areas from traffic, and mowing (if specified).

(5) Ensure that damaged, eroded, or barren areas are reestablished by the contractor, including repair or replacement of

mulch.

(6) Terms for measurement and acceptability of turf should be

stated in the specifications. Contact the designer if they are not.

3.10-3. SURFACE DRAINAGE/EROSION CONTROL. Landfill erosion control

structures are designed to reduce soil erosion by minimizing the

velocity of surface water and concentrating flows into protected

channels. Prevention of erosion requires temporary erosion control

protection and continuous maintenance until the permanent vegetative

growth is established. Permanent erosion control systems such as

benches, terraces, channels, and drainage ditches may also be

required.

a. Benches and Channels. Benches and channels are permanent
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3.10-3

erosion control structures that carry surface water from the landfill

cap to sedimentation basins. Perimeter berms may also be needed to

divert storm water from surrounding areas away from the landfill.

(1) Ensure that materials used (rip-rap, geotextiles, bedding

soil) meet specified requirements. 

(2) Verify benches and channels are constructed to the crosssections and grades indicated on the plans and specifications. 

(3) Visually inspect for dips and reverse grades along bench

and channel bottoms. 

(4) Ensure that the contractor is disposing of or reusing the

excavated material in accordance with the specifications.

(5) Ensure soils used to construct benches are placed at the

specified moisture content and compacted to the specified density.

(6) For channels at the toe of a landfill cover, verify the

outlet pipes for the cover drainage layer are not obstructed or

damaged during construction of the toe channel.

b. Gabions. Gabions are welded wire fabric structures that

enclose rip-rap and hold it in place. They are used as permanent

erosion protection for channels.

(1) Ensure that basket wire, lacing wire, and stone fill are as

specified. 

(2) Ensure that the foundation is prepared as specified. 

Inspect the foundation surface for smoothness immediately prior to

placing the filter fabric. 

(3) Ensure that the gabions are placed at the slopes and

elevations called for on the drawings. 

(4) All adjoining empty gabion units should be connected by

wire lacing along the perimeter of their contact surfaces. Ensure

that lacing is accomplished as described in the specifications. 

(5) The initial line of gabion baskets should be anchored by

partially filling them.

(6) Verify that stone filling operations proceed by careful

placement by hand or machine so welded wire fabric structures are not

damaged and to assure a minimum of voids between the stones. 

(7) Along all exposed faces, the outer layer of stone should be

carefully placed and arranged by hand to ensure a neat and compact

appearance. The last layer of stone should be leveled with the top of

the gabion to allow for proper closing of the lid and to provide an

even surface that is uniform in appearance. 

(8) Ensure that lids are stretched tight over the stone fill

using crowbars or lid closing tools until the lid meets the perimeter

edges of the front and end panels. The lid should be tightly laced

with tie wire along all edges, ends, and internal cell diaphragms by

continuous stitching. Ensure that all projections or wire ends are

turned into the baskets. 

(9) Do not allow the use of clip connections for the purpose of
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3.10-4

final lid closing.

(10) Where a complete gabion unit cannot be installed, the

basket should be cut, folded, and wired together to suit existing site

conditions. The mesh must be cleanly cut and the surplus mesh cut out

completely, or folded back and neatly wired to an adjacent gabion

face. 

c. Grout Bags. Grout bags are sometimes used to armor steep

channels to resist erosive flow velocities. Specifications and

manufacturer’s directions should be consulted for installation

instructions.

(1) Ensure grout bags are not pulling out of the anchor

trenches as the bags are filled with grout.

(2) Ensure grout bags are fully expanded with grout.

(3) Excess grout on the edges of the anchor trench should be

removed.

d. Sedimentation Basins. Sedimentation basins are impoundments

constructed to collect surface runoff and control its release to

prevent adverse impacts to adjoining properties and receiving

waterways. Construction of sedimentation basins is similar to

construction of other earthen embankments. Additional information is

available in Volume 2 of the Quality Assurance Representative’s Guide

in the chapter titled “Levee Construction and Earth Embankment

Construction for Dams”.

e. Silt Fences. Silt fences are made of woven geotextile

fabrics which are resistant to deterioration due to ultraviolet light

and heat exposure. The geotextile is attached to wooden stakes using

metal staples. 

(1) Verify the silt fence meets the specified material

requirements.

(2) Ensure the silt fence is securely fastened to the wooden

stakes. Typically, a minimum of 3 staples should be used to attach

the silt fence.

(3) Ensure that silt fence is installed where indicated by the

plans and specifications. However, try to be flexible in the

placement location so that areas where trenching will be difficult can

be avoided. 

(4) Verify the bottoms of the silt fence is buried to the depth

indicated on the plans and specifications (typically, 150 to 200 mm (6

to 8 inches)). The geotextile should be positioned on the uphill side

and the stake to the downhill side of the trench. 

(5) The trench should be backfilled so that at least 50 to 100

mm (2 to 4 inches) of the silt fence geotextile forms a “J” shape, with

the lower portion of the “J” pointing uphill. The trench should be

backfilled and the soil compacted over the geotextile so it is level

with the surrounding grade.

(6) Check the silt fences at least once per month for damage or

excessive silt accumulation. Additional inspections should be made

after large rainfalls and high winds. 
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3.10-5

f. Hay Bales. Hay bales serve the same function as silt

fences. 

(1) Verify that bales are tied firmly with wire or plastic ties

and are secured by wood stakes. 

(2) Verify bales are partially buried and staked in accordance

with the specifications.

g. Erosion Control Blankets. Erosion control blankets provide

temporary protection from erosion until the vegetative cover can be

established. They are typically made of interlocking wood fibers or

knitted straw. These materials are covered on both sides with a

biodegradable plastic mesh or interwoven thread. As the vegetative

cover becomes established, the erosion control blanket biodegrades and

disappears.

(1) Verify that the area to be covered is properly prepared,

fertilized, and seeded before the erosion control blanket is applied. 

All ground surfaces should be relatively smooth so that the erosion

control blanket lies in complete contact with the underlying soil.

(2) Biodegradable erosion control blankets are very sensitive

to water and ultraviolet light. Make sure these materials are stored

in dry conditions and protected from sunlight until needed.

(3) Ensure that the weight and type of the blanket is as

specified. If the erosion control material has defects or damage, it

should be rejected or repaired prior to use.

(4) If the material is to be repaired, torn or punctured

sections should be removed by cutting a cross section of the material

out and replacing it with a section of undamaged material. 

(5) Ensure overlaps are shingled in the direction of flow. 

(6) Verify ends and edges of the erosion control blanket are

pinned tightly to the ground so water cannot flow beneath the blankets

and cause erosion. 

(7) Ensure that staples used to hold the blanket in place are

as required in the specifications. The staples should be applied

vertically, keeping the blanket taut. 

(8) Make sure staples are not so long that they penetrate the

cover soil and damage underlying geosynthetics. 

(9) Check the specifications and manufacturer’s recommendations

for overlap and pin placement requirements. The following can be used

as general guidance:

& Adjacent rolls of erosion control material should be

overlapped a minimum of 75 mm (3 inches);

& Staples should secure the overlaps at 750 mm (2.5 ft)

intervals;

& Roll ends should overlap a minimum of 450 mm (18 inches);

and 

& The end overlaps should be stapled at 450 mm (1.5 ft)

intervals.
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3.11-i

CHAPTER 3.11

TEST FILL

Paragraph Page

3.11-1 GENERAL 3.11-1

a. Equipment 3.11-1

b. Preconstruction 3.11-1

 Submittals

c. Construction Submittals 3.11-1

3.11-2 PRODUCTS 3.11-2

3.11-3 EXECUTION 3.11-2

a. General 3.11-2

b. Placement 3.11-2

c. Tests 3.11-3

d. Approval 3.11-4

e. Removal 3.11-4

f. Full-Scale System 3.11-4

 Placement
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3.11-1

CHAPTER 3.11 TEST FILL

3.11-1. GENERAL. A test fill is a simulated section of the landfill

cover or liner. Test fills are constructed prior to full scale

construction for the following reasons:

 & To verify the contractor can construct the landfill cover

or liner as specified without damaging the geosynthetics;

& To determine if interface frictional resistance between

the various components of the landfill cover or liner is

adequate to prevent slope failures;

& To allow the contractor to determine placement methods for

natural soil components;

& To allow sealed double ring infiltrometer (SDRI) testing 

to be performed (Refer to ASTM D 5093 and EPA/600/R-93/182 

if a SDRI test will be performed as a component of the

test fill evaluation process); and

& To verify whether the field placement methods will achieve

the required hydraulic conductivity of the low

permeability clay layer.

Test fills are typically 10-15 m (30-50 ft) wide and 20-30 m (65-100

ft) long. The length of time which a test fill will be monitored

after construction varies from project to project and depends on the

type of testing which will be performed. 

a. Equipment.

Ensure that equipment used for the test fill is the same type

that is specified for full scale construction. 

b. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Other specifications require submittals related to the cap

or liner system. These submittals should be made and approved in

advance of the test fill section construction. 

(2) Test Fill Plan describing the proposed test fill section

construction. The plan should include the following:

& Drawings including plan views, sections, and details;

& Sequence of operations;

& Survey marker layout including monitoring to be performed;

& Surface water controls and diversion; and

& Equipment to be used including proposed operating speeds,

traffic pattern, and number of passes.

c. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.
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3.11-2

(1) Weekly Post-Construction Monitoring Reports including the

most up to date test results and survey data from the test fill. 

(2) Final Test Fill Construction Report which includes as-built

drawings, videos, all survey data and test results, and conclusions

related to test fill construction and monitoring. 

3.11-2. PRODUCTS. Ensure all materials used to construct the test

fill are the same as will be used for construction of the full-scale

landfill.

3.11-3. EXECUTION.

a. General.

(1) Verify the contractor is constructing the test fill to the

specified dimensions at the location shown on the drawings. 

Typically, the test fill should be a minimum of 3 to 4 times wider

than the compaction equipment and long enough to allow construction

equipment to achieve normal operating speed. 

(2) Verify the completed test fill slope is correct. The test

fill slope is critical if the purpose of the test fill is to determine

if interface frictional resistance is adequate between the various

layers of geosynthetics. 

(3) Layout.

(a) If surveys are to be performed on the test fill, a

coordinate system should be established with one axis parallel to the

bottom and top edges and the other axis parallel to the sides of the

test fill section. 

(b) The contractor should also establish a benchmark outside of

the landfill boundaries to ensure accurate surveys are made. 

b. Placement.

(1) Verify the area where the test fill will be placed is

cleared and grubbed as required by the specifications.

(2) Drainage controls should be constructed to divert runoff

around the test fill area. The drainage controls should be maintained

until the completion of the post-construction monitoring period.

(3) Verify the subgrade (existing landfill surface) is

compacted as described in the specifications.

(4) Foundation soil should be placed on top of the subgrade to

establish the required slope. 

(5) Check the plans and specifications to determine the minimum

thickness of the foundation soil layer beneath the test fill. This

layer is typically a minimum of 300 mm (12 inches) thick.

(6) Anchor Trench.

(a) Check the plans and specifications to determine if the test

fill should include an anchor trench. 
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3.11-3

(b) Verify the anchor trench is constructed to the correct

dimensions along the full width of the top of the test fill. 

(c) Check the plans and specifications to determine which

geosynthetics should be placed in the anchor trench.

(d) Verify the anchor trench is backfilled as specified.

(7) Survey Control Points.

(a) Survey control points typically consist of 450 mm (18 inch)

long steel pins set in the soil on top of and back from the edge of

the test fill. 

(b) Verify permanent marks are placed (painted) on each layer

of geosynthetic material to allow relative movements to be determined. 

(c) Survey control points are usually surveyed immediately

after construction and every 5 to 7 days thereafter over the life of

the test fill. 

(d) Horizontal and vertical movement is typically monitored to

the nearest 3.0 mm (.01 feet). Verify the specifications address the

maximum allowable relative movement of the test fill. Contact the

designer if this information is not provided. 

c. Tests.

(1) Post-Construction Monitoring.

(a) Ensure the contractor inspects the test fill daily and

reports its condition in the Construction Quality Control Daily

Reports. 

(b) Video taping is often required during construction and

post-construction monitoring to document the condition of the test

fill.

(2) Low-Permeability Clay Layer.

(a) Inspect the clay layer during construction to verify

materials and placement methods are as specified for full scale

construction. 

(b) If Shelby tube samples are taken for hydraulic conductivity

testing, they should be taken from the clay layer at locations you

specify. 

(c) Shelby tube samples should be extruded and visually

examined for signs of inadequate bonding between lifts. 

(d) Generally, at least one set of classification tests (ASTM D

422, ASTM D 1140, and ASTM D 4318) should be performed on each lift of

clay placed. 

(e) The contractor should also perform field density, moisture

content, and hydraulic conductivity tests (ASTM D 5084) on each lift

of the test fill clay layer. The specifications should indicate the

number of tests which should be performed per lift. 

(4) Geosynthetics Testing. Determine if leak, peel, and shear
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3.11-4

tests are required to be performed on the geomembrane seams. 

(5) Dismantling.

(a) After construction and monitoring of the test fill is

complete, the contractor should carefully remove the soil layer from a

small area (typically 3 m X 6 m (10 feet by 20 feet)) above the

geosynthetics. 

(b) Visually inspect the geosynthetics and document areas of

damage.

(c) Additional areas of the test fill section should be

examined in a similar manner if it appears the geosynthetics have been

damaged. The inspection operation is often videotaped.

d. Approval. Excessive slippage or damage to geosynthetics

resulting from the contractor's placement methods should result in

rejection of the contractor's placement methods.

e. Removal.

(1) After approval of the Final Test Fill Construction Report,

the contractor should remove the test fill section. 

(2) Determine the suitability of natural soils for reuse. If

reused, the contractor should stockpile and protect these materials. 

(3) Geosynthetics are usually removed and discarded.

f. Full-Scale System Placement.

(1) Do not allow the contractor to begin construction of the

full-scale liner or cover system until approval of the Final Test Fill

Construction Report. 

(2) Only methods and equipment used during test fill 

construction should be used for full-scale construction unless

otherwise approved.
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3.12-i

CHAPTER 3.12

GEOGRID

Paragraph Page

3.12-1 GENERAL 3.12-1

a. Preconstruction 3.12-1

 Submittals

b. Delivery, Storage 3.12-1 

 and Handling

3.12-2 PRODUCTS 3.12-2

Geogrid 3.12-2

3.12-3 EXECUTION 3.12-2

a. Installation 3.12-2

b. Penetrations 3.12-3

c. Covering 3.12-3
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3.12-1

CHAPTER 3.12 GEOGRID

3.12-1. GENERAL. Cover soil stability often becomes an issue for

slopes of 4 horizontal on 1 vertical or steeper. Geogrids are

reinforcement geosynthetics used in landfill covers and liners to hold

cover soils in place on steep slopes. Geogrids are formed by

intersecting and joining sets of longitudinal and transverse ribs with

the resulting open spaces called apertures. Two different classes of

geogrids are currently available: (a) stiff, unitized, geogrids made

from polyethylene or polypropylene sheet material, and (b) flexible,

textile-like geogrids made from high strength polyester yarns which

are joined at their intersections and coated with a polymer or

bitumen. Geogrids are classified as uniaxial or biaxial. Uniaxial

grids provide reinforcement in one direction only while biaxial grids

provide reinforcement in all directions.

Geotextiles are also used for reinforcement. Review Section 3.8

in addition to this section for QA inspection responsibilities for

reinforcement geotextiles.

a. Preconstruction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Manufacturer's QC test results. 

(2) Manufacturer's QC manual.

(3) Geogrid layout plan along with anchorage and connection

details.

(4) Pull-out resistance test results. 

(5) If mechanical geogrid connections are required, strength

test results for the connections should also be submitted. 

(6) Sample of geogrid (if required). 

b. Delivery, Storage, and Handling.

(1) A QA Representative should be present during delivery and

unloading of the geogrid to inspect for damage. 

(2) Verify that rolls are labeled with the manufacturer's name,

product identification, lot number, roll number, roll dimensions and

date manufactured. If the geogrid has a primary strength direction it

should also be identified.

(3) The QA Representative should record roll numbers, date

delivered, name of manufacturer, and product type. This data is used

to verify manufacturer’s QC data sheets have been submitted for the

rolls being delivered.

(4) Reject any rolls of geogrid damaged during delivery,

storage, or handling. No repairs should be allowed on damaged geogrid

or reinforcement geotextile.

(5) Do not allow rolls of geogrid to be dragged, lifted by one

end, or dropped to the ground.

(6) Temporary storage at the job site should be in a well 
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3.12-2

drained smooth area.

(7) The storage area should also be shaded or the geogrid

should be placed beneath an opaque cover. 

3.12-2. PRODUCTS.

Geogrid. 

(1) Cross check the roll numbers of the geogrid delivered to

the site against the roll numbers on the manufacturer’s QC test data

submittals to ensure they match. Ensure the geogrid meets the property

requirements outlined in the specifications for material type and

physical properties.

(2) Verify the pull-out resistance test results meet the

strength requirements specified between the geogrid and adjacent

soils. 

(3) Verify the same soil borrow source was used for the pullout resistance testing as will be used for full scale construction.

3.12-3. EXECUTION.

a. Installation.

(1) A QA Representative should be present at all times during

geogrid installation. 

(2) Do not allow personnel working on the geogrid to smoke or

wear shoes that could damage the geogrid.

(3) Geogrid is usually unrolled down slope and kept in slight

tension prior to cover soil placement. 

(4) Check the plans and specifications to see how the upper end

of the geogrid should be anchored. Proper anchorage is critical if

the grid is to function correctly. 

(5) Connections.

(a) Geogrid reinforcement may be joined with mechanical

connections or overlaps. Check the specifications to determine which

type of connection is required.

(b) Mechanical connections should be installed per the

specifications and manufacturer's recommendations.

(c) Verify the mechanical connection strength meets the

specified requirements.

(d) For overlap connections, check the specifications and

manufacturer recommendations for minimum overlap requirements.

(e) Splicing rolls of geogrid together on slopes greater than 4

horizontal on 1 vertical should generally not be allowed. If

permitted, the splices should be located as close to the bottom of the

slope as possible.

(f) If connections are required on slopes, they should be 
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3.12-3

staggered (generally a minimum of 2 meters (6 feet)) above or below

connections for adjacent rolls.

(g) The sides of adjacent geogrid rolls generally do not need

to be overlapped for slope reinforcement. However, ensure 100 percent

of the slope is covered with geogrid.

b. Penetrations.

(1) For pipe penetrations through the geogrid, only transverse

members of the geogrid should be cut.

(2) Verify That the load carrying longitudinal (roll direction)

members are spread around the penetration.

c. Covering. Refer to Chapter 3.9 Cover Soil Layer for

information on cover soil placement. 
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3.13-i

CHAPTER 3.13

GAS VENTING/COLLECTION

Paragraph Page

3.13-1 GENERAL 3.13-1

3.13-2 COLLECTION SYSTEMS 3.13-1

a. Continuous Blanket 3.13-1

 Systems

b. Well Systems 3.13-2

c. Collection Trenches 3.13-2

d. Piping and Conveyance 3.13-3

 Systems

e. Gas Monitoring Probes 3.13-3
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3.13-1

CHAPTER 3.13 GAS VENTING/COLLECTION

3.13-1. GENERAL. Landfill gas production results from vaporization,

chemical reactions, and biological decomposition. Biological

decomposition of organic materials results in the production of carbon

dioxide and methane. Other gases may also be generated depending on

the composition of the waste material. The following is a list of

potential impacts of landfill gas.

& Explosion hazard. Methane can migrate through the

subsurface and collect in adjacent structures creating a

potential explosion hazard.

& Vegetation distress. Landfill gases can distress the

vegetation on a landfill cover.

& Odor. Odor control becomes a potential concern if the

landfill is located adjacent inhabited areas.

& Physical disruption of cover components. Gas buildup

beneath the geomembrane can force the geomembrane to

protrude or “bubble out” from the cover. Landfill gases

can also cause desiccation cracking on the underside of

the clay layer resulting in an increase in permeability.

& Toxic gases. Gases produced by landfills can be toxic or

may not comply with regulatory emission criteria.

Gas control systems consist of collection, conveyance and outlet

components and are designed to vent either passively or actively. A

passive system allows the landfill gas to exit the collection system

without mechanical assistance whereas an active system utilizes

blowers to extract the gas. The gas is then either dispersed into the

atmosphere, flared, or collected and treated. This chapter briefly

discusses collection and conveyance systems and QA aspects for each

type of system. 

Additional information which may be applicable to landfill gas

collection systems can be found in the following chapters:

& Chapter 2 - Ground Water Extraction Systems;

& Chapter 3 - Drainage Layer;

& Chapter 3 - Geotextile;

& Chapter 3 - Pipe and Appurtenances; and

& Chapter 4 - Soil Vapor Extraction Systems.

3.13-2. COLLECTION SYSTEMS. The following paragraphs discuss

different types of landfill gas collection systems. If intrusive

drilling or trenching is performed within or near the landfill to

construct the gas collection system, check that the safety plan

addresses fire hazards associated with the possible presence of

methane gas. At a minimum, air should be monitored for flammable

gases and oxygen level.

a. Continuous Blanket Systems.
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3.13-2

(1) General. A continuous blanket system consists of a layer

of granular fill or a geonet located below the impermeable barrier

layer. Perforated horizontal collection pipes are sometimes

incorporated into the blanket to aid in the withdrawal of landfill

gas. Geotextile materials are sometimes used to prevent clogging of

the blanket system by fine grained soils. Vertical vent pipes are

used to vent the gas directly to the atmosphere or to transfer the gas

to a treatment system. 

(2) Quality Assurance.

(a) Check granular soils to assure that gradations meet the

specified requirements.

(b) Verify granular soils are placed to the specified

thickness. No density criteria is normally specified.

(c) Verify that pipes and geosynthetic materials conform to the

specifications.

(d) Geosynthetic materials should be kept clean prior to use.

b. Well Systems. 

(1) General. Well systems consist of a series of gas

extraction wells (perforated or slotted pipes) that penetrate into the

waste materials. The components of the wells are similar to that of

soil vapor extraction wells (i.e. riser, screen, gravel pack). Gases

collected in the well system are either passively vented to the

atmosphere or collected by an active system for treatment.

(2) Quality Assurance.

(a) Check that drill cuttings are disposed of as required by

the specifications.

(b) Check that the materials used for the casing, screen,

filter pack, and bentonite seal are as specified.

(c) Check that the well is set straight and true to line.

(d) Check that the surface completion of the well is as shown

on the drawings. 

(e) Assure that the completed well is visibly marked and

protected to prevent damage during future construction of the cover

system.

(f) Verify that an as-built installation diagram is submitted

for each well. The specific information to be included in the

installation diagram should be described in the specifications.

c. Collection Trenches. 

(1) General. Gas collection trenches consist of granular 

materials placed in a trench installed either in the waste material or

along the perimeter of the waste. Sometimes geomembranes are

incorporated to provide an additional barrier to gas migration. Gases

collected in the trench are either passively vented to the atmosphere

or collected with an active system for treatment.

(2) Quality Assurance. 
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3.13-3

(a) Check that the trench is constructed at the proper depth

and alignment. 

(b) Assure that granular backfill, geosynthetics, and pipes

meet specified requirements.

(c) Check that any collection pipes in the trench are placed at

the proper lines and grades.

(d) If geosynthetics are included in the trench, ensure that

subgrade/sidewall protrusions or backfill placement does not puncture

or damage the geosynthetics.

d. Piping and Conveyance Systems.

(1) General. Piping and conveyance systems for landfill gas

removal consist of well heads and non-perforated header piping. 

Generally, all piping will converge to a single header pipe which goes

to the gas treatment facility. 

(2) Quality Assurance.

(a) Assure that the collection piping materials are as

specified. Pipes are usually made of either HDPE or PVC. 

(b) Check that pipe connections are tight and non-perforated

header pipes have been leak tested.

(c) Check that the proper burial depths and pipe slopes are

maintained.

(d) Verify that the pipes slope towards condensate collection

tanks and do not have any dips or low spots where condensate can

collect and clog the pipe.

(e) Check that the specified valves, gages, gas monitoring

ports, and flexible couplings are installed at the well head.

e. Gas Monitoring Probes.

(1) General. In order to assure that the gas collection and

removal system is operating properly, a series of gas monitoring

probes are sometimes located around the perimeter of the landfill to

detect landfill gases that may be migrating off site. The monitoring

probes are small diameter wells which allow soil gas samples to be

collected. 

(2) Quality Assurance. 

(a) Generally, gas monitoring probes should be installed prior

to the installation of the landfill cover system. This allows the

probes to be monitored for off-site migration of landfill gases during

construction of the landfill cover system. 

(b) Check that the materials used for the casing, screen,

filter pack, and bentonite seal are as specified.

(c) Check that the probe is set straight and true to line.

(d) Check that the surface completion of the probe is as shown 
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3.13-4

on the drawings. 

(e) Assure that the completed probe is visibly marked and

protected to prevent damage from the future construction of the cover

system.

(f) Assure that an as-built installation diagram is submitted

for each probe. The information to be included on the installation

diagram should be described in the specifications.
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3.14-i

CHAPTER 3.14

OPERATION AND MAINTENANCE

Paragraph Page

3.14-1 GENERAL 3.14-1

Operation and Maintenance 3.14-1

 Submittals

3.14-2 EXECUTION 3.14-1

a. Ground Water 3.14-1

b. Landfill Leachate 3.14-2

c. Landfill Gas 3.14-2

d. Settlement 3.14-2

e. Vegetative Cover 3.14-2

f. Runoff Controls 3.14-3

g. Other Features 3.14-3

h. Maintenance Work 3.14-3
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3.14-1

CHAPTER 3.14 OPERATION AND MAINTENANCE

3.14-1. GENERAL. Operation and maintenance activities are required

to maintain the effectiveness of completed landfill covers and liners. 

Repairs may be required to correct the effects of settlement,

subsidence, or erosion. Gas extraction and leachate removal are

required for some landfills. Parameters such as ground water quality,

air quality, and underground gas migration are also monitored at some

landfills. The construction contractor is often required to perform

operation and maintenance on landfills for a specified period of time

(typically one year) after construction. The construction contractor

may also be required to write an operation and maintenance manual

during the year in which he operates the landfill. In other cases,

the operation and maintenance manual is written by the designer. This

chapter discusses the QA Representative’s responsibilities if the

construction contractor is required to perform operation and

maintenance for a specified period of time following construction.

Operation and Maintenance Submittals. The contractor should

provide operation and maintenance submittals as required by the

specifications. The following is a list of typical submittal

requirements.

(1) Operation and Maintenance Manual. The manual may include one

or more of the following:

& Air sampling and analysis plan;

& Ground water sampling and analysis plan; and

& Operation and maintenance procedures for the landfill

cover, sumps, leachate treatment facility, gas extraction

system, and gas treatment facility.

(2) Monthly Inspection and Operation Report.

(3) Monthly Water Treatment Plant Operation Report.

(4) Monthly Gas Treatment Plant Operation Report.

(5) Air, water, and leachate sampling reports.

(6) Notification of maintenance activities.

(7) Maintenance completion reports.

3.14-2. EXECUTION.

a. Ground Water. 

(1) Up gradient and down gradient monitoring wells should be

sampled after closure at the specified frequencies. Samples are

typically collected once every one to three months during the first

year after construction. 

(2) Verify that before each round of sampling, the ground water

elevation is determined for each well.
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3.14-2

(3) Verify samples are collected in accordance with the

sampling and analysis plan.

(4) Review the ground water sampling data for significant

changes in contaminant concentrations. 

b. Landfill Leachate. 

(1) Ensure that leachate levels within sumps are monitored at

the specified frequency.

(2) Verify that Leachate is collected from sumps to maintain a

head of less than 0.3 meters (12 inches) on the liner.

(3) Treatment and disposal criteria are site specific. Review

the plans and specifications to determine what these criteria are. 

c. Landfill Gas. 

(1) Verify the contractor periodically inspects the surface of

the landfill cover for bulges which may be an indication that gas is

collecting beneath the geomembrane. 

(2) The contractor should also monitor landfill gas

concentrations at compliance points every two to four weeks for the

first year after construction. Verify gas concentrations are at

acceptable levels.

(3) Compliance points may include gas monitoring probes,

boundary monitoring stations, well heads for passive systems, or

flares for active systems. 

(4) Verify samples are collected in accordance with the

sampling and analysis plan.

d. Settlement. 

(1) Verify the contractor is performing periodic inspections of

the landfill surface. The landfill cover should typically be

inspected monthly for signs of settlement and slope stability

problems. 

(2) Require additional select fill and top soil be placed in

areas where minor settlement has occurred. These areas should then be

reseeded.

(3) If a large depression develops which results in reverse

slopes, repairs to the low permeability layer and drainage layer may

be required to reestablish the correct slope. 

e. Vegetative Cover. Verify that the contractor is 

maintaining the effectiveness of the final cover by performing the

following tasks: 

(1) Maintaining temporary erosion control structures until the

vegetative cover is established and repairing erosion damage; 

(2) Reseeding areas with poor vegetative cover; 

(3) Mowing as appropriate for local conditions after the

vegetative cover has been established; and 
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3.14-3

(4) Keeping the surface of the landfill free of burrowing

animals and large vegetation. 

f. Runoff Controls. Verify the contractor is inspecting the

following runoff control features.

(1) Drainage terraces, ditches, and drop structures should be

inspected monthly by the contractor to ensure that erosion or other

problems are not present. 

(2) Detention ponds should be inspected monthly to ensure there

is sufficient storage available for runoff and the outlet works are

operating properly. 

(3) Outlets to the cover subdrainage system should also be

inspected monthly and kept clean and free flowing.

g. Other Features. Other features such as fences and perimeter

access roads should be maintained by the contractor during the one

year maintenance period.

h. Maintenance Work. 

(1) The contractor should provide notification in writing in

advance of conducting any non-routine or major maintenance activities. 

(2) A Government representative should be present during all

major maintenance activities.

(3) A maintenance completion report should be submitted by the

contractor when the work has been completed.

(4) The ultimate user/O&M representative should be involved

during the one year contractor O&M period. This will aid in a smooth

transition and ultimate acceptance of the completed project.
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4-i

CHAPTER 4

SOIL-BENTONITE SLURRY WALLS

Paragraph Page

4-1 GENERAL 4-1

a. Preconstruction 4-1

 Submittals

b. Construction Submittals 4-1

4-2 PRODUCTS 4-2

a. Materials 4-2

b. Equipment 4-2

c. Mixes 4-3

d. Quality Assurance Testing 4-3

4-3 EXECUTION 4-3

a. Work Platform 4-3

b. Trench Excavation 4-3

c. Placement of Slurry 4-4

d. Excavated Material 4-4

e. Trench Cleaning 4-4

f. Soil-Bentonite Backfill 4-4

 Mixing and Placement

g. Soundings 4-5

h. Treatment of the Top of the 4-5

 Completed Slurry Trench

i. Cleanup 4-5
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4-1

CHAPTER 4 SOIL-BENTONITE SLURRY WALLS

4-1. GENERAL. At hazardous waste sites, Soil-Bentonite (S-B) slurry

walls function as relatively impermeable barriers to either contain

contaminated ground water or redirect clean ground water around

contaminated areas. S-B slurry walls are typically a minimum of 600

to 1500 mm (2 to 5 feet) wide and are required to have an in-place

permeability of less than or equal to 1 X 10 cm/s. -7

The major construction activities involved in building an S-B

slurry wall are preparation of the site, slurry mixing, slurry

hydration, trench excavation, backfill preparation, backfill

placement, and site cleanup. The slurry is used to hold the trench

open until backfill can be placed. Slurry is composed of water with

4-8 percent sodium bentonite added. 

S-B backfill typically consists of a minimum of 2 percent

bentonite, 20-40 percent fines (silt and clay), and has a moisture

content of 25-40 percent. The density of the slurry in the trench

must be at least 240 kg/m (15 pounds per cubic foot) less than the 3 

density of the S-B backfill so that the S-B backfill will displace the

slurry in the trench during construction. The mix design used for the

S-B backfill can be specified by the Government or proposed by the

contractor based on preconstruction compatibility testing. 

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

 (1) S-B Backfill Testing Plan describing the equipment,

procedures, and materials to be used to determine an S-B backfill mix

design.

(2) S-B Backfill Testing Report. This report should include a

description of test results including proposed mix proportions,

gradations, slumps, densities, permeabilities, and moisture contents.

(3) Slurry Trench Implementation Plan describing the general

work sequence and layout of operations. The plan should include

locations for storage and slurry preparation areas, contractor

qualifications, equipment, utilization of excavated materials, trench

cleaning methods, slurry and S-B backfill preparation, and site

cleanup. Also, the contractor's plan should include a description of

QC equipment and test procedures, and the name of the off-site

laboratory proposed for use. 

(4) Bentonite. A sample of the proposed bentonite is often

submitted for QA testing.

(5) Backfill material. A sample of each type of backfill

material is often submitted for QA testing. 

(6) Water. Verify that mixing water test results comply with

the requirements indicated in the specifications.

b. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Bentonite test results and a certificate of compliance for

each lot of bentonite shipped to the site. 
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4-2

(2) Backfill gradation test results. Verify the backfill

material conforms to the specified ranges gradation, Atterberg limits,

and moisture content.

(3) As-built profile. Scale drawing and a profile of the

completed slurry trench. If S-B backfill materials were prepared in

batches, each batch should be delineated on the profile.

(4) Record of soundings taken during construction. 

(5) Bentonite slurry mix. Record of bentonite slurry mix

quantities, proportions of additives utilized, and adjustments in the

slurry mix.

(6) S-B backfill material mix. A record of S-B backfill

material mix quantities and adjustments.

(7) QC test results.

4-2. PRODUCTS. 

a. Materials.

 (1) Bentonite.

(a) Check that the bentonite conforms to the specifications. A

certificate of compliance from the supplier should provide the

specified criteria.

(b) Bentonite powder should be kept dry during storage.

(2) Water. Check that mixing water complies with the standards

specified. If the local water supply does not meet the specifications

the contractor may need to condition the water prior to use.

(3) Backfill Material. Check that the backfill material to be

used for the S-B backfill material conforms to the gradations

specified. In addition, Atterberg limits and moisture contents for

the backfill should conform to the specified values.

 

 b. Equipment.

(1) All equipment should be inspected in accordance with the

provisions of EM 385-1-1 and the inspection checklist should be

submitted by the contractor prior to use of the equipment.

(2) Trench Excavation Equipment. 

(a) Check that the excavation equipment is capable of

excavating the trench width in a single pass. Buckets utilized may be

perforated to allow the drainage of slurry, and may include bottom

cutter teeth.

(b) Check that the excavation equipment is capable of reaching

at least 1.5 m (5 feet) deeper (or other depth as specified) than the

maximum excavation depth as shown on the drawings.

(3) Mixing and Slurry Placement Equipment.

(a) Slurry mixing equipment should be capable of achieving 
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4-3

complete dispersion of bentonite and additives to produce a uniform

slurry. Typically, venturi mixers are used for this operation, in

conjunction with high-speed/high-shear centrifugal pumps.

(b) Check that stored slurry is mechanically or hydraulically

agitated while in slurry storage ponds or tanks. 

(4) Field Laboratory Equipment. Check that the specified field

laboratory equipment is on site and in good working condition.

c. Mixes.

(1) Initial Bentonite Slurry. Check that the proper percentage

of dry bentonite is added to produce the slurry, and that the slurry

conforms to the properties listed in the specifications.

(2) Trench Bentonite Slurry. 

(a) Verify slurry in the trench conforms to the properties

listed in the specifications. Check the specifications for testing

frequency of the trench slurry. 

(b) Verify that slurry is allowed to hydrate (typically, for a

minimum of 8 hours) prior to being placed in the trench.

(c) Slurry additives to increase or decrease viscosity should

be approved prior to use. It is advisable to consult with the

designers about the use of additives to control or adjust slurry

properties. 

(3) S-B Backfill Material.

(a) Verify S-B backfill material meets the properties listed in

the specifications. 

(b) Look for poorly mixed S-B backfill. S-B backfill should be

thoroughly mixed so that all particles are coated with slurry.

d. Quality Assurance Testing. Check the specifications or QA

Plan to see if samples need to be submitted for QA testing. 

Typically, samples for QA testing should be collected at the same time

as QC samples, however, at a reduced frequency. This allows

comparison of the QA and QC test results. Ensure QA and QC sample

numbers are correlated so that test results can be easily compared. 

4-3. EXECUTION.

a. Work Platform. Check that the work platform is constructed

to the lines and grades shown on the drawings. Check for proper

compaction and material requirements as described in the

specifications.

b. Trench Excavation. 

(1) The up-gradient portion of the slurry trench should be

excavated before the down-gradient portion of the slurry trench. 

(2) Check that the excavation is vertical (within 2 percent). 

This is normally accomplished with plumb line measurements.

(3) Check that the full depth of the trench has been excavated 
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4-4

prior to placement of the S-B backfill.

(4) Measure the depth of the trench when the top of the key

layer has been reached, and also after the key has been excavated into

the key layer. The soil that is excavated should be continuously

logged by QA personnel to verify that subsurface conditions are

similar to those anticipated.

(5) Generally, the trench excavation should not precede the toe

of the S-B backfill slope by less than 9 meters (30 feet) or more than

30 meters (100 feet). Just prior to extended non-work periods, S-B

backfill may be brought to the toe of the excavation (to minimize the

amount of open trench).

(6) Check that the full depth of the trench has been reached

and overlapped at all intersecting segments of the wall. Generally, a

minimum overlap of 1500 mm (5 feet) of overlap is required.

(7) Check for trench collapses by depth probing. Ensure that

collapsed soils are removed prior to S-B backfill placement. 

c. Placement of Slurry. 

(1) Slurry should be placed in the trench at the start of

excavation.

(2) Monitor the slurry level within the trench. Typically,

slurry is maintained a minimum of 900 mm (3 feet) above the ground

water level and no more than 600 mm (2 feet) below the surface of the

work platform.

(3) Check the density of the slurry, especially near the 

middle and bottom of the trench, to ensure that density requirements

are met. Check the specifications for testing frequencies. 

 (4) If the density of the slurry in the trench is too high

(generally greater than 1360 kg/m (85 pcf)), desanding of the slurry 3

may be required. This process may involve the use of desanding

equipment, or replacing the slurry in the trench with fresh slurry.

d. Excavated Material.

(1) Check that the excavated materials are properly stockpiled. 

They may have to be covered if vapor emissions are a problem.

(2) Check that stockpile placement is not too close to the

trench, which may cause trench collapse. Stockpile placement distances

should be described in the specifications. Contact the designer if

they are not. 

e. Trench Cleaning. Verify that the trench bottom has been

cleaned prior to S-B backfill placement. Often, the trench bottom is

cleaned by the use of an air lift pump to remove material which has

settled out of the slurry. The trench bottom should be checked after

periods of inactivity such as an overnight work stoppage. 

f. Soil-Bentonite Backfill Mixing and Placement.

(1) Check that the S-B backfill material has been thoroughly

mixed into a homogeneous mass. Depending on the project, S-B backfill

may be mixed in a separate mixing area and trucked to the 

trench or mixed along the side of the trench with a dozer. If mixed 
EP 415-1-261

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4-5

using a dozer, verify the mix is not being diluted with subgrade

soils. 

(2) The S-B backfill should be initially placed into the bottom

of the trench by tremie or clamshell methods. A sloped starter trench

outside the limits of the work can also be constructed. the starter

trench allows the S-B backfill to slide down to the bottom of the

trench. 

(3) Subsequent batches of S-B backfill should be placed at the

top of the backfill slope.

(4) The slope of the S-B backfill face should be probed to

assure that a constant slope is maintained. This will assure that no

pockets of slurry are trapped within the S-B backfill.

g. Soundings.

(1) Check that soundings of the excavation and S-B backfill are

taken every 6 meters (20 feet) or as otherwise specified.

(2) The following elevations are typically recorded: a) Top

of key stratum; b) Bottom of trench excavation; c) Bottom of

trench prior to backfilling; and d) Profile of the backfill slope.

(3) An "as-built" profile should be kept by the contractor

which includes descriptions of materials encountered, extent of

excavation after each day's work, and S-B backfill batch placement

locations.

h. Treatment of the Top of Completed Slurry Trench. 

 (1) Check the specifications to determine if a temporary soil

cover should be placed over completed portions of the slurry trench. 

Generally, the final trench cover should not be installed immediately

after S-B backfill placement to allow settlement to occur. 

(2) Prior to the installation of the final trench cover,

settled areas should be filled with approved material.

i. Cleanup. Excess trench spoils, unused S-B backfill, and

excess slurry should be properly disposed of as indicated in the

specifications.
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5-i

CHAPTER 5

SOLIDIFICATION/STABILIZATION

Paragraph Page

5-1 GENERAL 5-1

a. Preconstruction 5-1

 Submittals

b. Construction Submittals 5-1

5-2 PRODUCTS 5-2

a. Materials 5-2

b. Equipment 5-2

5-3 EXECUTION 5-2

a. Utility Clearances 5-2

b. Stockpiles 5-2

c. Field Demonstration 5-3

d. Operation 5-3

e. Tests 5-4

f. In Situ Solidification 5-5

 /Stabilization
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5-1

CHAPTER 5 SOLIDIFICATION/STABILIZATION

5-1. GENERAL. Solidification/stabilization (S/S) refers to treatment

processes that are designed to accomplish one or more of the

following:

 & improve the handling and physical characteristics of the

waste; & decrease the surface area of the waste mass across which

leaching of contaminants can occur; and

& reduce the solubility of hazardous constituents in the

waste.

S/S is performed by mixing contaminated materials with one or

more reagents such as cement, lime, or fly ash. S/S is applicable for

the treatment of contaminated liquids, soils, and sludges. The final

product of an S/S process may vary from a granular, soil-like material

to a cohesive solid depending on the amount of reagents added and the

type of waste being treated. S/S can be performed as an in-situ

process or the contaminated material can be excavated and treated

above ground in some type of mixing unit.

a. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Solidification/Stabilization Work Plan. Review the work

plan to ensure the following items are adequately addressed.

(a) Information to demonstrate the S/S contractor meets the

qualification requirements specified.

(b) The proposed mix design to be used in treating the

contaminated material. 

(c) Bench scale treatability study test results (if required).

(d) Equipment proposed for mixing, batching, and process

control. Process flow diagrams, mixing times, and processing rates. 

Any anticipated pretreatment of the contaminated material should also

be identified. 

(e) Drawings indicating dimensions and layout of the S/S

system. 

(f) Air emissions, dust, and noise from the system should be

identified and estimated. Control systems proposed for use should be

described. 

(g) QC procedures which covers control of batch proportions,

control of mixing time, and post-treatment testing. 

(h) Proposed stockpile design. Ensure the stockpile design

meets the criteria outlined in the specifications.

b. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.
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5-2

(1) Qualifications of key personnel. Do not allow individuals

identified in the specifications as key personnel to start work until

their qualifications have been submitted and approved.

(2) A field demonstration report including pre-treatment and

post-treatment test results, batch proportions, mixing time, and

mixing speed. 

(3) Reagent certificates of analysis should accompany each

shipping unit.

(4) QC test results. 

(5) Mixing time, mixing speed, and mix proportions for each

batch of material treated.

5-2. PRODUCTS.

a. Materials.

(1) Water. Require chemical testing of the proposed water

source when the water is of questionable quality.

(2) Reagents. Verify the reagents meet the specified

requirements. Reagents should be shipped in properly labeled

containers with instructions for handling and storage.

b. Equipment. Verify that mixing equipment has a positive

means for controlling the mix proportions, maintaining the time of

mixing constant, and maintaining the appropriate speed of rotation of

the mixing unit.

(a) Check the reagent silos and feeders during operation to

ensure caking of the reagents is not occurring which could cause

variations in the reagent feed rate. 

(b) Verify that scales, meters, and volumetric measuring

devices used for measuring contaminated material, reagents, and water

for S/S processing are accurate to within the specified limits. 

(c) Verify measuring devices are being calibrated at the

specified frequency. 

 

5-3. EXECUTION.

a. Utility Clearances. Check that all utility clearances have

been received for any subsurface work and that there are no overhead

hazards that will interfere with the S/S unit.

b. Stockpiles. Verify stockpiles are constructed in accordance

with the specifications. Typically, stockpiles for storing

contaminated material include the items listed in the following

paragraphs.

(1) A chemically resistant impermeable geomembrane liner. 

Make sure the ground surface on which the geomembrane is placed is

free of objects which could damage the membrane. 

(2) An impermeable geomembrane cover with a minimum thickness

of 10 mils. 
EP 415-1-261

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5-3

(3) Berms surrounding the stockpile to prevent run on and

runoff of liquids. 

(4) Check to see if leachate is collecting within the stockpile

liner. Ensure leachate collected from the stockpile is handled in

accordance with the specifications. Typically it will be analyzed

(and treated, if necessary) prior to disposal or it may be reused in

the S/S process. 

c. Field Demonstration.

(1) Prior to full-scale S/S operations, a field demonstration

is often performed on a representative amount of the contaminated

material.

(2) Verify the full-scale processing equipment is being used

for the field demonstration. Reagents (including water source), mix

ratios, and mixing procedures used during the field demonstration

should be the same as those used for the remainder of the S/S work.

(3) Verify contaminated material used for the field

demonstration is obtained from locations outlined in the

specifications.

(4) Prior to performing the field demonstration, contaminated

material to be used for the field demonstration is usually tested to

verify it contains representative levels of contamination.

(5) Verify the treated material from the field demonstration

meets the physical and chemical criteria listed in the specifications.

(6) Require additional test runs if the treated material does

not meet the specified requirements.

(7) The estimated increase in volume resulting from S/S

treatment is often determined during the field demonstration. Volume

increase is determined by comparison of the volume of contaminated

material to be treated to the volume of treated material. 

(8) Determine if the specifications allow the contractor to

continue to process contaminated material while waiting for test

results from the test run.

d. Operation.

(1) Weather Conditions.

(a) Check the specifications to see if there is a minimum

temperature below which solidification/stabilization should not be

performed. 

(b) Do not allow contaminated material to be treated if it

contains any frozen material. 

(c) Do not allow S/S to be performed during periods of heavy

rainfall if this will result in the addition of excess water to the

mixture.

(2) Ensure that dissimilar materials which testing has

indicated will require the use of different S/S mix ratios are not

mixed together.
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5-4

(3) Visually monitor the physical appearance of the material

being treated. If there is an obvious change in color, odor, or

texture of the material, consideration should be given to requiring

additional QA testing.

(4) Oversize Material. Verify oversize material that cannot be

handled by the S/S unit is removed, treated and disposed of in

accordance with the specifications.

(5) Verify the contractor is not diluting the soil to be

treated by excavating and treating materials which are outside the

specified area of treatment. 

(6) Verify confirmation samples are taken at the specified

frequency for the side walls and bottoms of excavations to verify all

contaminated material has been removed. Excavations should generally

not be backfilled until confirmation tests confirm that all

contaminated material has been removed.

e. Tests. (1) Verify mixing time, mixing speed, and the amounts of

contaminated material, reagents, and water added to each batch are

recorded by the contractor and maintained within the limits specified

in the approved S/S Work Plan. 

(2) Verify treated material is segregated into stockpiles for

post-treatment testing so that material can be retreated if it does

not meet the post-treatment testing criteria. Stockpile size should

be equal to or less than the volume at which the most frequent QC test

is run. Each stockpile should have a visible number to aid in the

tracking process. The numbers should be correlated to the QA/QC

samples which have been collected. 

(3) If the treated material will be placed directly into an onsite landfill, verify the contractor is segregating and tracking the

location of each batch of material so that it can be located if

reprocessing is necessary.

(4) Post-treatment testing specified should be performed on

representative samples of treated material. Require the contractor to

perform additional testing on treated material that appears to be

poorly mixed or have improper mix proportions. 

(5) Verify QC specimens are allowed to cure as described in the

specifications. 

(6) Typically up to 6, 2-4 inch diameter samples are made for

each round of QC testing. The samples are allowed to cure (typically

1 to 7 days) and then tested for leachability of contaminants. 

Physical tests such as unconfined compressive strength and hydraulic

conductivity are also sometimes required.

(7) For in situ S/S jobs, verify the specifications indicate

the depth below ground surface at which QA/QC samples are to be

collected. Ensure the contractors method of sample collection can

obtain a sample which is representative of the specified depths.

(8) Require reprocessing and/or retesting to be performed on

treated material that does not meet the physical and chemical

requirements listed in the specifications. The specifications should

address how retesting and reprocessing will be handled QC or QA tests 
EP 415-1-261

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5-5

fail. Contact the designer if retesting and reprocessing is not

addressed.

(9) The S/S mix design may be changed by the contractor based

on the characteristics of the material being treated. Require

additional test runs if there is a question about the new mix design

proposed.

(10) Check the specifications or QA Plan to see if samples need

to be submitted for QA testing. Typically, samples for QA testing

should be collected at the same time as QC samples, however, at a

reduced frequency. This allows comparison of the QA and QC test

results. Ensure QA and QC sample numbers are correlated so that test

results can be easily compared. 

(11) Ensure the treated material from the S/S process, upon

meeting the physical and chemical testing criteria, is disposed of as

required by the specifications.

f. In Situ Solidification/Stabilization. In situ S/S is

typically performed using large diameter augers which inject reagents

into the soil and mix the reagents and soil together. The following

are inspection items which are specific to in situ S/S.

(1) Verify the auger is drilling vertically into the

contaminated material. This is especially critical where the

contaminated soil is deep.

(2) Typically, the rate of entry and withdrawal of the auger is

controlled and synchronized with the rate of injection. Verify

reagents are being injected uniformly and in the right proportion

throughout the zone of contamination.

(3) Closely monitor the depth of penetration of the auger to

ensure the entire depth of contaminated soil is treated.

(4) Samples are usually collected from the treated soil at

specific depths within the treated soil column. Verify the method of

sample collection can retrieve an isolated sample from the specified

depth. 
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6-i

CHAPTER 6

SOIL VAPOR EXTRACTION SYSTEMS

Paragraph Page

6-1 GENERAL 6-1

a. Equipment 6-1

b. Preconstruction 6-1

 Submittals

c. Construction Submittals 6-2

d. Start-Up Submittals 6-2

e. Related Requirements 6-3

f. Site Evaluation 6-3

6-2 PRODUCTS 6-3

a. Above-Ground Equipment 6-3

b. Below-Ground Equipment 6-4

6-3 EXECUTION 6-5

a. Installation 6-5

b. Tests 6-8

c. Start-Up 6-9

d. Operation and Maintenance 6-10
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6-1

CHAPTER 6 SOIL VAPOR EXTRACTION SYSTEMS

6-1. GENERAL. This section describes the installation of soil vapor

extraction (SVE) systems. SVE systems are intended to remove volatile

contaminants from the soils above the water table by either

evaporation or biodegradation. The air is extracted from wells or

trenches (and in some cases injected) using air blowers or vacuum

pumps and associated above ground equipment. SVE projects include

system installation, start-up, and usually limited operations and

maintenance. This section does not cover vapor treatment or air

discharge permit requirements. Refer to EM 1110-1-4001, Soil Vapor

Extraction and Bioventing for more detail on the design, construction,

and operation of soil vapor extraction systems.

a. Equipment.

(1) Well Drilling Equipment.

(a) Use only drilling equipment not requiring the use of

liquids (water, drilling mud) for installation of air injection or

extraction wells. 

(b) If the soil vapor extraction wells will also be used for

the extraction of ground water and/or floating product, refer to the

checklist on Ground Water and Leachate Collection for appropriate

equipment. Use of fluids should be avoided if possible in any event.

(2) Refer to Chapter 3 on covers and liners for equipment

appropriate for installation of any required surface cover.

(3) Trenching equipment for below-grade piping installation only

need be large enough to reach required excavation depth and provide

necessary trench width.

b. Preconstruction Submittals. The contractor should provide

preconstruction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Drilling and Well Installation Plan which describes:

& the drilling method and equipment;

& well installation procedures;

& soil/rock logging procedures and forms;

& soil sampling and sample handling procedures; and

& well construction diagrams.

Verify that the drilling subcontractor has read the well

installation specifications prior to mobilization to the site.

(2) Qualifications for the driller should be submitted if

licensed drillers are required in that state. Verify that the

qualifications meet the specifications and any state requirements. 

The qualifications, including education and experience, of the

geologist or engineer responsible for logging the materials

encountered in drilling should also be submitted for information.
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6-2

(3) Catalog information on:

& well screen and casing;

& cement and/or bentonite well sealant;

& precast well head vaults (if applicable);

& piping;

& blower(s) and associated equipment (or package unit

containing these items);

& gauges and controls; and

& electrical components.

(4) Gradation test results for filter pack material and piping

bedding/backfill, if required. 

(5) Shop drawings on any fabricated above-ground equipment.

c. Construction Submittals. The contractor should provide

construction submittals as required by the specifications. The

following is a list of typical submittal requirements.

(1) Boring logs for extraction, injection, or monitoring wells. 

(2) Proposed well locations or well screen placement may be a

submittal if well construction was left to the contractor based on

conditions encountered. Proposed locations and construction must

achieve the objectives of the system. Contact the designer if

uncertainty exists about the adequacy of the proposal.

(3) Well construction diagrams for all wells installed under

the contract. Include copies of any permits required by state or

local authorities.

(4) Airflow test results for individual extraction (or

injection) wells. These are determined by testing air yields at 

various pressures/vacuums and are used to verify design assumptions.

(5) Leak test results on wells, piping, and above-ground

equipment.

(6) Backfill density test results, if required.

(7) Well chemical sampling results from initial sampling. 

(8) Alignment test results, for blower and motors.

d. Start-up Submittals. The contractor should provide start-up

submittals as required by the specifications. The following is a list

of typical submittal requirements.

(1) Completed Pre-startup Checklist. This checklist requires

that a review be made of the equipment and controls to assure that the

system will perform safely and as expected. This would include

testing of blower alignment and rotation, control circuits, alarm

settings and operation. Verify items on the checklist with the

contractor, if possible.
EP 415-1-261

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6-3

(2) Start-Up Monitoring Plan. This plan identifies procedures

for initial start-up of the system including step-by-step procedures

for valve settings, circuit checks and energizing, and monitoring.

(3) Start-up monitoring results. These results must be provided

within the time required by the specifications or the regulators.

(4) Operations and Maintenance Plan.

(5) Air Discharge Permit. The requirements for obtaining an

air discharge permit vary by project and by state. Verify

coordination with applicable regulatory agencies prior to startup. 

Such coordination is best started during design.

e. Related Requirements. Consult other Quality Assurance

Representative Guides for ground water extraction well installation

(if water extraction is conducted jointly with soil vapor extraction),

piping systems, underground utility systems, and ventilation, air

supply and distribution systems.

f. Site Evaluation. 

(1) Other Contaminant Sources. Evaluate the potential for

other nearby contaminant sources or air-flow pathways prior to

initiation of construction. These can include building basements,

utility corridors, industrial shops, aboveground/underground fuel (or

waste oil, solvent) storage tanks. Alert the designer to any such

condition that was not considered in design.

(2) Power Supply. Verify that adequate utility services (e.g.

electrical power) are available for the equipment.

(3) Noise. Identify any constraints on the acceptable noise

levels at the site. This may require use of silencers or equipment

housings.

6-2. PRODUCTS.

a. Above-Ground Equipment. There are several above-ground

components in a soil vapor extraction system. These may be specified

separately or as a package system. If specified as a package system,

there may be overall requirements for total pressure drop; air

throughput; electrical phase, current draw, voltage; and maximum inlet

vacuum/pressure. There may be specifications for specific components

of the package system as well. Specifications must be carefully

reviewed prior to approving use of a package system. Verify that

equipment installed is consistent with the contract documents and

catalog information submitted prior to construction.

(1) Blower/Motor. SVE requires a blower or vacuum pump

typically driven by electric motor. Compliance with the

specifications for type and size of blower, motor rating and

horsepower, or vacuum/pressure range and airflow rate must be assured. 

The motor must be appropriately rated for the area classification. 

(2) Condensate Tank. The condensate tank must meet

specifications, particularly for capacity, pressure/vacuum rating,

construction, and level sensors. Verify that the tank has a suitable

means to drain condensate. Confirm that any rental equipment is empty

and was cleaned following the last use.
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6-4

(3) Particulate Filter. Verify that the particulate filter

meets specifications for type, pressure drop, and filter size or

removal efficiency.

(4) Silencers. Silencers must meet specification for flow

capacity and noise reduction in the frequency range emitted by the

blower. 

(5) Piping. All piping for above- and below-grade installation

must meet specifications for material, diameter, schedule, and joints. 

Piping may be installed above ground. If PVC or other plastic piping

is installed above ground, verify that the piping is resistant to

degradation from sunlight.

(6) Off-gas Treatment Equipment. Not covered here.

b. Below-Ground Equipment.

(1) Screen. Verify that well screen slot type, slot size and

shape meet specified requirements. Also verify material composition

and wall thickness are consistent with the specifications. Well

screen should be new and cleaned and wrapped at the factory. On-site

storage should be in a clean, safe location where the screen will not

be damaged by other equipment.

(2) Casing. Verify that well casing schedule and material meet

specified requirements. Assure that joints can be made air-tight. 

Well casing should be new and cleaned and wrapped at the factory. Onsite storage should be in a clean, safe location where it will not be

damaged by other equipment.

(3) Filter Pack. The filter pack must meet the specified

requirements gradation. If none is given, check that the filter pack

is uniform sand or gravel of gradation large enough to prevent entry

of the pack through the screen slots. Uniform means it has a

uniformity coefficient of 2.5 or less. The uniformity coefficient is

the sieve aperture passing 60 percent of the material divided by the

sieve aperture passing 10 percent of the material. 

(4) Well Seal. Bentonite used for well seals must be sodium

type and provided in the form required by the specifications; dry

powder is not appropriate for bentonite seal installation. Pellets or

granules are preferred for bentonite seals. Bentonite powder is

acceptable for use in cement-bentonite grout. Cement must meet

specified requirements for type and must be mixed with the appropriate

amount of water. In the absence of a specified mix, allow the use of

26-35 liters (6-8 gallons) of water to one 43 kg (94 pound) bag of

cement. Bentonite may be mixed with the cement to reduce shrinkage. 

If not specified, allow a 3-5 percent addition of bentonite in the

cement by weight. The bentonite powder should be mixed with the water

before adding the cement to assure adequate mixing.

(5) Well vaults. Assure compliance with specification. Verify

consistent diameters of vault penetrations with associated casing,

piping, or utility conduits. Vault covers must be appropriate for

traffic conditions if flush-mounted. Assure that adequate means of

opening large vault covers are provided.

(6) Piping. Piping must meet requirements for schedule,

diameter, and joints. Above-ground piping must be UV resistant.
EP 415-1-261

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6-5

6-3. EXECUTION.

a. Installation.

(1) Wells. Well installation is difficult to evaluate after

the wells are completed. Direct oversight of installation process is

recommended.

(a) Permits. Confirm that the necessary notifications/drilling

permits have been obtained from the installation, State, County or

appropriate agency before any drilling commences.

(b) Utility Clearances. Check that all utility clearances have

been received for the subsurface work and that there are no overhead

hazards that will interfere with raising or lowering the drill mast.

(c) Decontamination. Well drilling equipment must be

decontaminated prior to use on the site and between boreholes.

(d) Locations. Verify that the drilling location conforms to

the specifications. If it is impossible to install the wells in a

specified location, determine the best alternative location that meets

the requirements of the design. If there are any questions as to the

design goals or a possible location, contact the project designer to

confirm a new location.

(e) Borehole Diameter. Borehole diameter must meet

specifications. In the absence of a specified size, require boreholes

4 inches in diameter larger than specified well screen and casing. If

the well or monitoring point is placed by direct push methods, no

requirement for borehole size is applicable.

(f) Borehole Depth. Borehole depth must either meet

specification or achieve the objective. Depths are often tailored in

the field based on conditions encountered. Instructions to the field

from the designer must clearly identify the objectives of the wells. 

If there is any doubt about the adequacy of the borehole depth,

contact the designer.

(g) Safety. Confirm that safe drilling procedures are used and

that an exclusion zone is well defined around the drill rig. Also

determine that required safety equipment is present and that it is

operated in accordance with the requirements of the SSHP.

(h) Cuttings Disposal. If required, confirm that all drill

cuttings and or liquids are drummed and disposed of in accordance with

the approved work plan.

(i) Sampling and Logging. Adequate logs must be made by a

qualified geologist or engineer of the materials encountered. Soil

sampling should be performed to support the logging. Verify that soil

samples are obtained for chemical analysis as directed by the sampling

and analysis plan. Chemical samples provide a baseline contaminant

level against which later sample results obtained following operation

can be compared. Such samples are more appropriately obtained from

monitoring points rather than extraction wells since soils at the

extraction wells will be subjected to the most intense remediation and

are not representative of the majority of soils at the site. 

(j) Screen and Casing Placement. Length of screen and casing

must match specified requirements. Verify that joints are air-tight 
EP 415-1-261

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6-6

and secure. Screen and casing must be suspended in the hole to assure

proper alignment. Centralizers may also be required.

(k) Filter Pack Placement. Filter pack should be placed dry

via a tremie pipe. Pack material must be kept clean. Verify depth to

pack after placement to assure adequate thickness.

(l) Seal and Grout Placement. & Place bentonite seal materials dry via tremie pipe, unless

placement depth is less than 10 feet.

& Verify proper thickness and location of bentonite. 

Bentonite must not be placed in the screened interval.

& Bentonite seal must be adequately hydrated with clean or

distilled water. Hydration must be conducted for a period

of time and by a method meeting the specifications. In

the absence of specified requirements, hydration must be

allowed for a minimum of 1 hour and a maximum of 4 hours

prior to placement of the grout.

& Grout must be placed by tremie pipe submerged in the grout

until the grout flows to the surface.

& Require the contractor to "top off" the grout as

exfiltration causes the grout to settle.

(m) Wellhead Completion and Vault Placement. Well vault

placement depends on the type of vault. The contractor must use care

to avoid damage to well casing during vault placement. Below-grade

completions must prevent surface water from running in. Open drain

holes are not compatible with air-tight surface seal requirements. 

(n) Surveys. Well locations and elevations must be surveyed. 

Wells are typically surveyed to the nearest 1 foot horizontally and

.01 foot vertically.

(2) Collection Trenches and Below-Grade Piping. Underground

piping installation requirements are covered in detail in Volume 1,

General Information and Site Work. General guidance is provided here. 

Normal excavation techniques are assumed; use of pipe jacking,

directional drilling, or trenching/pipe laying machines have other

requirements not covered here.

(a) Trench Dimensions. The trench width is typically 610 mm

(24 inches) plus pipe diameter. 

(b) Trench Bottom Preparation and Pipe Placement. Thrust

blocking is typically not required for air conveyance piping. Proper

preparation and placement includes the following steps:

& level to required grade to promote drainage of condensate

or other liquids;

& remove rocks and angular debris from the subgrade;

& scarify trench bottom and lower sides if trench is to be

used as a collection (not utility) trench and ensure

excessive mud/clay smeared on trench surfaces is removed;

& install screen and piping in manner minimizing debris in 
EP 415-1-261

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6-7

the lines;

& prevent surface water from running in;

& join pipe and/or screen in a manner consistent with

material and manufacturer's instructions; and

& comply with all safety requirements.

(c) Access Port. An access port to allow later survey or

measurement should be required in collection trenches. Verify that no

fitting or joint will prohibit survey or maintenance equipment from

accessing the piping.

(d) Trench Spoil Disposal. Verify that potentially

contaminated soils excavated from the trench are appropriately

stockpiled and disposed of in accordance with the specifications

and/or regulation.

(e) Filter Pack/Backfill Placement. Filter pack or coarse

bedding material as required by the specifications should be placed in

the trench before piping/screen placement. Filter pack should be

placed at least 150 mm (6 inches) above the pipe prior to any

compaction for typical 100 mm (4 inch) diameter PVC schedule 40

pipe/screen. Larger diameters or weaker pipe material may require

more cover prior to compaction. Remainder of specified backfill must

be compacted to required density in the prescribed lifts. If lift

thickness is not specified, allow up to 200 mm (8 inch) lifts.

(f) Cleaning. Contractor should blow all debris from the lines

prior to start-up. Debris must not be blown into the screen or

condensate tank.

(3) Above-Ground Equipment and Piping. Volume 4, Special

Construction, Conveying Systems, Mechanical, and Electrical Features

covers many of the electrical, above ground piping, and air handling

systems which are applicable to soil vapor extraction. General

guidance is provided here. A project-specific Pre-startup Checklist

is recommended to assure that all components are properly installed.

(a) Blowers. Blowers must be:

& vibration isolated;

& aligned with drive motors;

& checked for rotation direction;

& inspected for appropriate guards, housing, and shields, as

per manufacturer’s recommendation and safety requirements;

and 

& lubricated in accordance with manufacturer's requirements.

(b) Above-Ground Piping and Valves. Above ground piping must

be:

& protected from UV degradation if not inherently resistant;

& protected from traffic or vandalism;

& cleaned of all debris;
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6-8

& suitably supported and anchored;

& securely joined by air tight connections, including

flexible connections;

& sloped to drain/collect condensate; and

& checked for proper valve operation.

Flow control valves must be provided at each trench header pipe

or well head. Verify clear access to all valve boxes.

(c) Condensate Knock-outs, Particulate Filter, and Relief

Valves. Verify:

& condensate tank has proper connection to air piping and

drain line, or if the drain is not connected that the

valve is shut;

& easy access is provided to condensate tank drain and

particulate filter;

& particulate filter is equipped with the specified filter;

& vacuum relief valve is provided upstream of the blower and

pressure relief valve is provided downstream and both

operate properly; and

& all connections are tight.

(d) Electrical, Control and Instrumentation System. Verify:

& gauges are calibrated, provided in specified locations and

have ranges that are appropriate for conditions expected;

& gauges should read in the middle 50 percent of range

during operation;

& electrical continuity and appropriate grounding is

provided for equipment operation and lighting;

& electrical connections are placed according to the plans

and specifications. Also verify the connections are

securely made and insulated;

& shut down controls and alarms function as required; and

& process control logic is consistent with contract

documents.

 b. Tests.

(1) Leak Tests. 

(a) Piping should be checked for leaks using either a

hydrostatic, air-pressure, or vacuum tests. Ensure valves are closed

at all well-heads and at the blower. If leakage is discovered, verify

the tightness of each connection.

(b) Well short-circuiting is difficult to verify. Look for

drastically lower than expected well head vacuum at design flow 
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6-9

rates, or pressurize well, wet area around well head with soapy

solution and observe any bubbling indicating air leakage around casing

or well head.

(2) Soil Testing.

(a) Confirmatory QC or QA gradation tests on filter pack or

bedding material may be required. If testing procedures are not

specified, require ASTM D 422, Particle Size Analysis of Soils.

(b) Density testing of trench backfill above the filter pack may

be required to ensure the backfill provides an air-tight seal. 

Compaction testing to determine maximum density and optimum moisture

should follow ASTM D 698, Testing Method for Laboratory Compaction

Characteristics of Soil Using Standard Effort. In-place density

testing should be measured using ASTM D 2922 (Nuclear Density Gauge

Method), ASTM D 1556 (Sand Cone Method), and/or ASTM D 2167 (Rubber

Balloon Method).

(3) System Checks. A start-up checklist should be completed

prior to operating the system. This requires tests of electrical,

control, and instrumentation systems. See paragraphs above for

additional detail.

c. Start-up. Start-up procedures are very site-specific. 

Refer to Chapter 7, Start-Up Requirements, EM 1110-1-4001, Soil Vapor

Extraction and Bioventing for a discussion of start-up strategy and

procedures. The start-up process can take days to weeks and is often

dependent on the "fine tuning" of off-gas treatment equipment.

(1) System Operator Qualifications. The qualifications of the

operator in charge of start-up should be reviewed for adequate

experience and education on the type of equipment used at the site. 

Note that the “operator” may be the construction contractor or a

subcontractor or may be hired as a separate contractor. 

(2) Pre-Startup Checklist. The pre-startup checklist must be

carefully followed to assure that the equipment is properly installed

and wired prior to start-up. Appropriate valve settings must be

checked prior to blower start to assure air flow to the blower. 

(3) Start-up.

(a) Start-up should be initiated with the atmospheric air bleed

valve fully open. Once blower(s) are started, these can be

incrementally closed to draw in subsurface air without risk to the

blower(s). 

(b) The operator must monitor all flow rates and vacuums at

individual wells and at blower inlet and outlet and compare to design

assumptions. The operator must then balance flow based on system

objectives and subsurface response. Verify that all gauges are

reading in an acceptable range. If not, the contractor should replace

gauges as necessary.

(c) Operator must check for plugging of particulate filters and

collection of condensate soon after the system is started,

particularly if there was the possibility of debris or moisture in the

line. 

(d) Vacuum (or pressure) response at monitoring points should

be recorded at system start-up to verify proper well operation and to
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6-10

estimate air permeability. These data should be compared to design

assumptions and should be used as a basis for deciding when steadystate flow conditions are reached. Steady-state flow is necessary to

complete start-up.

(e) Temperatures upstream and downstream of the blower(s)

should be observed for abnormal rise. Blower motor current draw

should also be noted for comparison to motor specifications. Any

indication of abnormal conditions may be basis for blower shutdown and

system repair or adjustment.

(f) Chemical sampling of soil, extracted soil gas, and/or

condensate should be performed as required for determining treatment

system performance. Verify that sampling is done according to the

approved contractor Chemical Data Quality Management Plan.

(g) Start-up Report. A report documenting all monitoring and

sampling results should be prepared.

d. Operation and Maintenance. It is important for QA 

Representatives overseeing contractor operations to understand the

basic principles of soil vapor extraction and the project objectives. 

Proper operation of the system is as critical as proper construction. 

Construction personnel often are responsible for overseeing a year or

more of operation. 

(1) Refer to the Soil Vapor Extraction and Bioventing Engineer

Manual, EM 1110-1-4001, Chapter 8, Operations and Maintenance for

further information.

(2) Verify that all equipment is maintained in accordance with

the vendor's requirements.

(3) Condensate recovery and disposal must be done in accordance

with applicable specification requirements and regulations.

(4) Check particulate filters for plugging (most likely only a

problem early in the system operation).

(5) Monitor air flow rate (flow from each well and total flow),

well head vacuum, monitoring point vacuums, blower inlet and outlet

temperatures, blower amperage, water table response (water levels),

and vapor concentrations (contaminants, oxygen, etc. from each well

and before and after treatment) as required by the O&M plan. Refer to

EM 1110-1-4001 for more information.

(6) Operational strategy is very site specific. In some cases,

as the contaminant concentrations go down, cycling the operation of

wells may allow more efficient use of the blower. In other cases, the

flow rate from wells may be reduced as contaminant concentrations

diminish. For petroleum contaminated sites, a conversion from soil

vapor extraction to bioventing may be appropriate after contaminant

removal rates drop.

(7) High fuel vapor concentrations in the extracted air can

result in potentially explosive conditions or operating problems for

the off-gas treatment system. High fuel vapor concentrations may

require bleeding in of atmospheric air through a relief valve. 

(8) Maintain adequate records of the data collected.
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7.1-i

CHAPTER 7.1

GENERAL INFORMATION

FOR GROUND WATER TREATMENT FACILITIES

Paragraph Page

7.1-1 GENERAL 7.1-1

a. Presubmittal Conferences 7.1-1

b. Submittals 7.1-1

7.1-2 PRODUCTS 7.1-1

Materials/Equipment Requirements 7.1-1

7.1-3 EXECUTION 7.1-2

7.1-4 OPERATION AND MAINTENANCE 7.1-2

a. Operator’s Requirements 7.1-2

b. Operation and 7.1-2

 Maintenance Manuals

c. Piping and Instrumentation 7.1-2

 Diagrams

d. Spare Parts 7.1-2

7.1-5 MONITORING SYSTEMS 7.1-2

a. Instrumentation Controls 7.1-2

b. Plant Operations and 7.1-3 

 Compliance Monitoring

c. Laboratory Equipment and 7.1-3

 Supplies
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7.1-1

CHAPTER 7.1 GENERAL INFORMATION

FOR GROUND WATER TREATMENT FACILITIES

7.1-1. GENERAL. The following chapters of this document were

developed to assist QA Representatives with inspections during

construction and operation of ground water treatment facilities. The

information provided covers items commonly overlooked or inadequately

covered in specifications and questions that commonly arise during

construction and operation activities. The EPA guidance document

entitled “Remedial Technologies Screening Matrix and Reference Guide”

(EPA/542/b-94/013) provides additional information about the treatment

processes discussed in this document.

a. Presubmittal Conferences.

To facilitate major equipment submittals for a ground water

treatment facility, presubmittal conferences may be held to clarify

supplier requirements. The project designer, construction personnel,

contractor, supplier, and applicable subcontractors are normally in

attendance at these meetings. 

 b. Submittals. (1) Almost all ground water treatment processes are comprised of

several separate units that are connected by pumps and piping. 

Contractor submittals for each unit must be reviewed carefully prior

to installation to ensure the units conform with the plans and 

specifications. 

(2) The contractor should provide construction submittals as

required by the specifications. The following is a list of typical

submittal requirements:

(a) Permits or substantive requirements of permits;

(b) Contractor requirements for experience;

(c) Site, facility, and equipment layout; and

(d) Warranties.

7.1-2. PRODUCTS. 

Material/Equipment Requirements. 

(1) Many ground water treatment plants use chemicals and

equipment that are very specialized. The chemicals can be hazardous. 

Review the Health and Safety precautions before using. 

(2) Verify the materials and chemicals conform to the

specifications. Seemingly small differences or oversights could

result in serious failures. 

(3) Materials must be compatible with all chemicals that they

will come into contact with. For example, acids may require the use

of special pipe. Deviation from the specifications could result in

the pipe rapidly corroding and failing. An air stripper blower that

is either over or under sized will cause the air stripper to perform

below design standards. This might not be recognized until the 
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7.1-2

process is in operation and discharge permit limits are not being

met. 

(4) Assure that all ferrous materials and materials damaged by

exposure to sunlight or water have been properly coated per the

specifications. 

(5) Verify that tank and piping dimensions are correct.

7.1-3. EXECUTION. It is important that during the initial startup

and debugging of the plant that stream compositions, temperatures,

pressures and flow rates of each unit in the process be measured to

ensure they conform to the design. The designer of the plant and the

equipment vendor should provide the detailed procedures to perform

these tasks. The contractor should submit a detailed start-up and

testing plan. The plan should be reviewed by the designer. Verify

that the plant is operating according to design before entering the

operations and maintenance phase. The failure of any one unit to

perform as designed could cause the whole process to perform poorly or

fail. Close cooperation with the designer and the vendor is critical

to the timely startup and debugging of a new treatment process. 

7.1-4. OPERATION AND MAINTENANCE.

a. Operator's Requirements. Licenses and certifications for

treatment plant operators and supervisors vary from state to state.

Operator licenses/certifications must be checked for compliance with

contract specifications. Many processes/operations do not have full

time operators. Contact the designer if it appears that the number of

hours are not adequate to safely/properly operate the plant.

b. Operation and Maintenance Manuals. Verify that each piece

of equipment has an O&M manual and a description of how that piece of

equipment fits into the overall process. Verify that O&M manuals are

complete and understandable. There should be one comprehensive O&M

manual that describes how all equipment operates together. The

operator should become familiar with the manuals. Keep track of each

Government copy of the O&M manual. These manuals tend to disappear. 

Verify that all O&M activities are tracked in a log. 

c. Piping and Instrumentation Diagrams. Verify that complete

and detailed piping and instrumentation diagrams (P&ID’s) and computer

logic diagrams for the entire process are supplied. These are needed

to troubleshoot and isolate process control problems during startup

and operation. Verify that the equipment safety shutdowns and safety

interlocks are functioning. 

d. Spare Parts. Ensure spare parts and special tools required

in the specifications are provided. The contractor should inventory

spare parts on a regular basis and provide reports indicating spare

parts inventory and usage.

7.1-5. MONITORING SYSTEMS.

a. Instrumentation Controls. Instrumentation and controls are

perhaps the most important aspect of the ground water treatment

facility. The use of a pre-submittal conference between the 

designer, contractor, and instrumentation/control supplier can 
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7.1-3

prevent problems during construction. Adherence to plans and

specifications is especially critical during installation of control

sequences. All control loops should be physically verified to be sure

they have been correctly installed and operate correctly. Close

interaction with the designer to rectify problem areas will prevent

future problems. Verify that each instrument has operating,

calibrating and maintenance instructions and operates correctly.

b. Plant Operations and Compliance Monitoring. Typically there

are three types of chemical sampling and monitoring required during

plant operation. These are initial operation monitoring, routine

operation monitoring and permit compliance monitoring.

(1) Verify that the purge line on the sampler has a location to

discharge to (floor drain, etc.). 

(2) Verify that the sampler has the capability of controlling

the sample rate when sampling a pressurized line.

c. Laboratory Equipment and Supplies. 

(1) Verify that the construction package has defined all

utilities required within the laboratory area. For example, many

laboratory hoods require gas piping for operation. If this is the

case, ensure that the utility drawings indicate a gas feed. 

(2) Determine if vacuum connections are required. 

(3) Verify that all specified refrigeration units, cabinets,

automated samplers, and equipment are provided. 

(4) Perform an inventory of glassware, tubing, spare parts,

etc. to be provided by the contractor before turnover of the plant.
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7.2-i

CHAPTER 7.2

PUMPS, PIPING, VALVES AND TANKAGE

Paragraph Page

7.2-1 GENERAL 7.2-1

7.2-2 PROCESS PIPING AND VALVES 7.2-1

a. Pressure Testing 7.2-1

b. Pipe Layout 7.2-1

c. Piping Schedule 7.2-1

d. Process Valves, Flow 7.2-1

 Meters, and Miscellaneous 

 Appurtenances

e. Shop Drawings 7.2-1

f. Variations 7.2-1

7.2-3 PROCESS/SLUDGE PUMPS AND BLOWERS 7.2-2

a. Process and Sludge Pumps 7.2-2

b. Seal Water 7.2-2

c. Pump Pads 7.2-2

d. Diaphragm Pumps 7.2-2

e. Factory and Field Testing 7.2-2

f. Blowers 7.2-2

7.2-4 PROCESS TANKS AND TOWERS 7.2-2

a. Coatings and Nozzles 7.2-2

b. Supports 7.2-2

c. Carbon Steel Tanks and Towers 7.2-2

d. Paint Defects 7.2-3

e. Footings 7.2-3

f. Large Tank Construction 7.2-3

g. Pressure Tanks 7.2-3

h. Operation and Maintenance 7.2-3
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7.2-1

CHAPTER 7.2 PUMPS, PIPING, VALVES, AND TANKAGE

7.2-1. GENERAL. Pumps, piping, valves, and tanks should be pressure

and leak tested in accordance with the specifications. Care should be

taken to ensure that the specified testing pressure is used. Fifty

percent over maximum operating pressure is often selected to provide

an adequate factor of safety. If hydraulic surges are a system

possibility, the test pressure should reflect the anticipated maximum

surge pressure plus a factor of safety. It is especially critical to

verify that all equipment that contains acids or bases is constructed

according to specifications. Failure to do this could result in

serious equipment failure and injury. Secondary containment systems

should be leak tested prior to acceptance.

7.2-2. PROCESS PIPING AND VALVES.

a Pressure Testing. When pressure/leakage testing double wall

piping, ensure that an acceptable method for pipe repair has been

defined in the event the carrier pipe or containment pipe does not

meet pressure testing requirements.

b. Pipe Layout. The specifications should require the

contractor to provide an as-built pipe legend which defines pipe type

(air, process water, potable water, chemical feed, etc.) with respect

to color and pipe labeling. For example, process water may be labeled

as “PW” on a green pipe. This should be reflected on the pipe legend. 

Ensure that there is no cross connection between process water, fire

protection water, and potable water. Process water is the non-potable

water that is typically utilized for general house-keeping activities,

wash down, backwash water, pump seal water, and cooling. Non-potable

water is utilized as process water to reduce overall water consumption

within a treatment facility. Piping should be laid out to allow ample

room for maintenance and removal of equipment.

 c. Piping Schedule. It is critical that the contractor

complies with the plans and specifications for pipe sizes, materials

of construction, interior linings, exterior coatings, thickness class,

secondary containment, insulation and freeze protection, joint and

pressure test requirements, and listed standards. Typically, a piping

schedule is provided by the designer for clarity. The piping schedule

should define all piping used in the treatment facility, including

air, process water, potable water, and chemical feed. The actual

layout of the piping in the building is field determined and will be

submitted by the contractor for approval.

d. Process Valves, Flow Meters, and Miscellaneous

Appurtenances. Ensure that the contractor provides valves, flow

meters, and appurtenances of the same type and by the same

manufacturer to the greatest extent possible. The design package

should contain a valve schedule and labeling system for ease of

construction.

e. Shop Drawings. Accurate, contractor provided, shop drawings

for piping, valves and appurtenances are critical. The valve

schedule/labeling system is important to allow the contractor to

provide complete, concise shop drawings. 

f. Variations. As construction progresses, and the piping 
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7.2-2

systems come together, there will be many small changes in piping

configuration and location of appurtenances which may require the

designer's approval. The majority of the time, these changes are a

result of variations in prefabricated equipment, ease of installation,

improved O&M, safety, etc. These changes will ultimately result in a

better overall product. It is very important that these variations

are documented on the shop drawings daily and checked by the QA

Representative weekly.

7.2-3. PROCESS/SLUDGE PUMPS AND BLOWERS.

a. Process and Sludge Pumps. A variety of pumps and blowers

are required for a ground water treatment system. Typically, a pump

schedule is provided in the plans and specifications to indicate pump

use, type, flow and head requirements. 

(1) Verify that blowers and pumps are the specified size. 

(2) Verify that the pump rotation is correct by bumping the

motor (briefly turning the pump on). 

(3) Verify the pump and motor are aligned according to the

specified procedures prior to operation.

b. Seal Water. Determine if seal water must be provided to

cool bearings or seals in any of the pumps. A drain must also be

provided if seal water is required.

c. Pump Pads. Pump pad locations should be defined on the

contract drawings. Ensure that pumps are leveled during installation

on the pad.

d. Diaphragm Pumps. For diaphragm pumps, ensure that the air

feed to the pump is of adequate quality. This may require the

installation of a dryer system to prevent freeze-up. Check the vendor

literature to determine if a particulate filter and lubricator are

required. 

e. Factory and Field Testing. Following installation, it is

the contractor’s responsibility to ensure that the pumps are tested

for operability. The supplier normally provides performance curves

for the pumps.

f. Blowers. Blowers may need to be balanced to prevent

vibration. Large blowers may require anti-surge protection, flexible

piping connections, and vibration isolation of the foundation.

7.2-4. PROCESS TANKS AND TOWERS.

a. Coatings and Nozzles. Coatings and linings as well as pipe

nozzle sizes and locations should be shown on the shop drawings and

verified on the tanks when delivered. 

b. Supports. Ensure that adequate external support per the

specifications is provided for tanks over 1 meter (3 feet) tall and

for elevated tanks.

c. Carbon Steel Tanks and Towers. Check that the tank finish

conforms with the required mil thickness (if painted). Verify that

the primer is compatible with the paint. Sandblasting is often 
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7.2-3

required prior to painting. Review the specifications to determine

what type of material should be used for blasting and what finish

(near-white versus white) is required.

d. Paint Defects. Inspect for abrasions on all painted

surfaces. Require the contractor to repair any abrasions, cuts, and

scratches.

e. Footings. Verify that footings and anchor bolts are

constructed according to the specifications.

f. Large Tank Construction. Ensure that all sections of the

tank shell have been accurately rolled and do not have a “dished” or

“egg-shape” appearance.

g. Pressure Tanks. Verify that tanks which will be pressurized

are designed, constructed, and tested in accordance with applicable

ASME pressure codes. Verify the ASME seal is present on the tank name

plate.

 h. Operations and Maintenance. 

(1) Inspect pumps, piping, valves and tankage for leaks and

corrosion. 

(2) Ensure the contractor is routinely removing sand and other

material from tanks and towers. 

(3) Tank site glasses need to be checked periodically to

determine tank liquid levels and verify automated tank liquid level

sensors are functioning properly. 
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7.3-i

CHAPTER 7.3

METALS PRECIPITATION

Paragraph Page

7.3-1 GENERAL 7.3-1

7.3-2 PRODUCTS 7.3-1

a. Equalization Tank 7.3-1

b. pH Adjustment Tank 7.3-1

c. Coagulation Tank 7.3-1

d. Flocculation Tank 7.3-2

e. Clarifier Tank 7.3-2

f. Filter 7.3-2

g. Sludge Thickener 7.3-2

h. Sludge Filtration 7.3-2

7.3-3 EXECUTION 7.3-2

a. Level Mounting Surface 7.3-2

b. Construction Connections 7.3-2

c. Access Port 7.3-2

d. Finished Floor 7.3-2

e. Unit Clearance 7.3-3

f. Appurtenances 7.3-3

g. Operation 7.3-3
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7.3-1

CHAPTER 7.3 METALS PRECIPITATION

7.3-1. GENERAL. Precipitation is a technology used to remove toxic

dissolved metal contaminants from ground water. In ground water

treatment applications, the metal precipitation process is also used

to remove non toxic metals (iron, calcium, and manganese) that could

cause fouling and plugging of other treatment processes such as air

stripping, carbon adsorption, and chemical oxidation. Metal

precipitation converts dissolved heavy metal ions to insoluble salts

that will precipitate (settle) out of the water. The precipitate is

then removed from the treated water by physical methods such as

clarification (settling) and filtration.

Precipitation is often performed in several tanks in series and

consists of pH adjustment, coagulation, flocculation and settling. In

the first tank, the pH is raised by the addition of a reagent such as

lime or caustic. The water then flows to a second tank where the

dissolved metals react with the reagent to form insoluble salts

(coagulate). These insoluble salts combine into larger floc particles

(flocculate). The water is then moved with low shear pumps or by

gravity to a clarifier where the floc particles settle relatively

quickly to the bottom of the tank. Additional chemicals are sometimes

added to enhance the precipitation. In some designs, multiple

operations identified above may be done in one tank. The resulting

sludge in the bottom of the tank is then removed. Typically, the

treated process water requires filtration to remove any traces of floc

prior to the next treatment process. Often times, the sludge is

further concentrated using a sludge thickening tank and a filter

press. The thickened sludge is often a hazardous waste and must be

disposed of in a RCRA hazardous waste treatment, storage, and disposal

facility. 

7.3-2. PRODUCTS

a. Equalization Tank. Ground water is often pumped directly

into an equalization tank prior to treatment. The purpose of the

equalization tank is to reduce variation in ground water

characteristics such as flow rate and contaminant concentration. The

equalization tank is usually cylindrical in shape and may be made of

metal, plastic or concrete. The tank may have a mechanical mixer or

air sparger to help keep the contents mixed. If the ground water

contains volatiles, the tank may be covered and vented (using a

blower) to an air pollution control device such as a carbon adsorber. 

The tank may also contain a mechanical device to remove sludge or it

may need periodic manual cleaning.

b. pH Adjustment Tank. In many cases, ground water flows by

gravity or is pumped from the equalization tank into a pH adjustment

tank where the pH is raised, causing metals to become insoluble and

precipitate. The most common chemicals used are lime and caustic. If

lime is used, a lime slaker unit will be installed that mixes the dry

lime with water and pumps it into the pH adjustment tank. If caustic

is used it is pumped into the tank from a drum or caustic storage

tank. Verify that pH adjustment tanks are accessible as lime or

caustic supplies will need to be routinely replenished. Also, verify

that the tank is made of the materials stated in the specifications. 

Automatic instruments measure the pH in the tank and control the rate

of lime or caustic addition. The pH adjustment tank is kept mixed

with a mechanical mixer.
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7.3-2

c. Coagulation Tank. Ground water flows from the pH adjustment

tank into a coagulation tank. This tank is equipped with a mechanical

mixer which allows dissolved metals to react and form insoluble salts.

d. Flocculation Tank. Ground water flows from the coagulation

tank into a flocculation tank. Here the insoluble metal salts form

large insoluble particles called floc. Sometimes a chemical

(typically a polymer) is pumped into the tank to help in the formation

of floc. Floc is kept in suspension in the water by gently mixing

with a mechanical mixer.

e. Clarifier Tank. Ground water flows from the flocculation

tank to the clarifier tank. Here the floc settles and is removed. 

Clarifiers may be cylindrical or rectangular in shape and made from

either metal or plastic. In other cases, a more complex clarifier

unit with inclined plates may be specified. The unit may have a

scraper on the bottom to remove the settled floc (sludge), a sloped

bottom with a drain for removing the sludge, or a flat bottom that

must be cleaned manually. Clarifier operation is usually controlled

by weirs which must distribute flow evenly. It is also critical that

the weir be set at the correct elevation to control the hydraulics.

f. Filter. A filter is used to remove any floc that does not

settle out in the clarifier. The filter unit could be a low pressure

or high pressure sand filter or a cartridge filter if the system is

small. The solids filtered out are returned to the clarifier tank. A

further discussion of filters is found in section 7.4.

g. Sludge Thickener. The sludge from the clarifier tank

usually contains about two per cent solids. This sludge is pumped to

a sludge thickener where it is allowed to consolidate to a

concentration of about five per cent. Chemicals (polymers) are

sometimes added to improve thickening (dewatering). A further

discussion of sludge thickening is contained in section 7.8.

h. Sludge Filtration. The thickened sludge is further

dewatered in a filter. Most often, the filter type is a plate and

frame filter press, however, a vacuum belt filter is also occasionally

used. The filtered material (filter cake) is generally a hazardous

waste and must be disposed of off site in a RCRA hazardous waste

landfill. Further discussion of sludge filtration is contained in

section 7.8

7.3-3. EXECUTION. 

a. Level Mounting Surface. For small, pre-fabricated units, an

obvious concern is that a level surface is constructed for system

mounting. This is especially important for clarifiers where each weir

must be carefully leveled.

b. Construction Connections. Construction of the connection

between the tank wall and the concrete floor of the treatment facility

is critical in preventing leaks. 

c. Access Port. If an access port is cut in a tank side to

facilitate construction, the opening should have rounded corners to

allow for ease of repair. 

d. Finished Floor. If a scraper mechanism is used in the 
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7.3-3

bottom of a clarifier, the finished floor must be smooth enough to

allow the scraper to operate properly. Normally this is accomplished

through the placement of grout and use of the scraper mechanism in the

clarifier to ensure a flat surface with acceptable tolerance. If the

scraper mechanism is utilized to finish the floor, ensure that the

squeegees are adequately cleaned following use. 

e. Unit Clearance. If the top of the clarifier unit is placed

near the ceiling, adequate clearance for the removal of the drive

mechanism must be maintained. This may also be accomplished through

the use of a sky light. 

f. Appurtenances. All equipment and controls required to

operate chemical precipitation units should be provided in easily

accessible locations to facilitate system operation and maintenance. 

This includes items such as flow controls, level controls, pH probes,

and ORP (Oxidation-Reduction Potential) probes.

g. Operation. Operation of the metals precipitation unit

involves monitoring system performance. Metal precipitation units

must be closely controlled. Small changes in pH (0.1 - 0.3 pH units)

can significantly reduce the amount of metals that precipitate,

potentially resulting in violation of discharge permit limits. 

(1) Verify the operator addresses items such as even flow

distribution, inadequate settling, insufficient or overdosing of

chemicals, incorrect pH/ORP and effluent clarity.

(2) The operator should develop a sludge wasting schedule to

remove settled solids from the metals precipitation clarifier.

(3) Look for potential problems with metals precipitation units

such as algal blooms, poor floc formation, and poor settling

characteristics. Algal blooms may be avoided by covering the unit to

prevent exposure of the water to sunlight. Poor floc formation and

poor settling characteristics may indicate improper chemical reagent

use and/or dosages. 

 (4) Verify that the sludge cake conforms to the acceptance

requirements of the disposal facility. High moisture content may

cause the sludge to be rejected.

 (5) Verify that the sludge is manifested correctly before being

shipped off site. Correct manifesting can be complex. Refer to EP

200-1-2 for additional information on manifesting.
EP 415-1-261

15 Jul 97

7.4-i

CHAPTER 7.4

FILTRATION

Paragraph Page

7.4-1 GENERAL 7.4-1

7.4-2 PRODUCTS 7.4-1

7.4-3 EXECUTION 7.4-1

a. Air Blowers 7.4-1

b. Filter Media 7.4-1

7.4-4 OPERATION AND MAINTENANCE 7.4-1

a. Turbidity Breakthrough 7.4-1

b. Mud Ball Formation 7.4-1

c. Buildup of Oil and Grease 7.4-1

d. Carbonate Buildup 7.4-1

e. Back Washing 7.4-1

f. Cracks/Contraction 7.4-2

g. Loss of Media 7.4-2

h. Air Binding 7.4-2

i. Gravel Mounding 7.4-2

j. Media Upset 7.4-2
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15 Jul 97

7.4-1

CHAPTER 7.4 FILTRATION

7.4-1. GENERAL. Filtration removes suspended solids and precipitated

metals from water by forcing the water through a porous medium using a

pressure differential. Filtration can be used as a pretreatment or

post-treatment process. There are various filtration systems

available to meet project specific requirements. These include: 

gravity filtration, pressure filtration, continuous backwash

filtration, bag filtration, and cartridge filtration.

7.4-2. PRODUCTS. The most commonly used filter types are granular

media filters, precoat filters, cartridge filters, and bag filters. 

Verify filters conform to the plans and specifications for size,

dimensions, and materials of construction.

7.4-3. EXECUTION.

a. Air Blowers. If air scour is used to clean the filter,

ensure that the air blower meets applicable decibel requirements for

noise control. 

b. Filter Media. Placement of the filter media in a filtration

system is critical to the successful operation of the unit. Normally,

it is the supplier’s responsibility to ensure that the filter media is

placed appropriately. Verify correct placement of the media during

installation.

7.4-4. OPERATION AND MAINTENANCE. Commonly encountered problems in

the filtration of ground water include turbidity (suspended solids)

breakthrough, mud ball formation, buildup of grease, oil and

carbonates, development of cracks and contraction in the filter bed,

loss of filtering media, air binding, gravel mounding, and media

upset. 

a. Turbidity Breakthrough. Unacceptable levels of turbidity

may occur in the effluent before terminal head loss is reached. This

problem is corrected by pretreating with filter aid chemicals 

upstream of the sedimentation tank or the filter.

b. Mud Ball Formation. Masses of solids, dirt, and media

sometimes clump together and create mud balls which sink into the

filter bed, reducing the effectiveness of filtering and backwash. 

Auxiliary washing processes (e.g.,air scour, surface wash) with, or

followed by, water wash should be used to correct this situation.

c. Buildup of Oil and Grease. Emulsified oil or grease can

accumulate within the filter bed. Air and surface wash usually help

eliminate this problem. It may be necessary to install a washing

system using sodium hypochlorite or special solutions.

d. Carbonate Buildup. Carbonate buildup can occur on media

after lime neutralization. For small systems, improving process

control over the neutralization step or an acid rinse should be used

to correct this situation. 

e. Back Washing. Back washing is performed to remove

materials which have accumulated in filters. Operational problems of 
EP 415-1-261

15 Jul 97

7.4-2

filtration units are usually associated with blinding and bridging

within the media. This is indicated by more frequent backwash demands

and reduced unit effectiveness. This problem must normally be

rectified through modification of upstream processes. Other

operational concerns deal with the frequency of back washing. Control

systems may be set on a timer, calling for backwash after a preset

time frame. The timer setting should be adjusted to optimize the

length of filter runs without excessive head loss. The length of

filter backwash and rinse may be manually adjustable to allow complete

cleaning of the filter without wasting backwash water. This method of

control is contrasted by another type which relies upon differential

pressure through the filter bed. In either event, backwash is

normally an automated process which requires little operator

attention. Air scouring of filters is sometimes performed if

backwashing is no longer effective at restoring clogged filters. 

Occasionally, the filter material must be replaced or replenished.

f. Cracks/Contraction. Cracks can develop when the filter is

not cleaned properly. The backwash and air scour operations should be

adjusted if this occurs.

g. Loss of Media. Loss of media can occur during back washing

or through the underdrain system. This can be caused by backwash

rates that exceed the recommended flow.

h. Air Binding. Air binding occurs when the head loss at any

point in the filter exceeds the static head (water depth) above that

point. When this occurs, dissolved gases in the water are released

and form bubbles in the bed, further aggravating the head loss

problem. Sometimes excessive air or water backwash rates that exceed

the suppliers recommendations can entrap air in the beds as well. To

correct this situation, the contractor should backwash the filter to

allow 20 percent maximum bed expansion or at a rate recommended by the

media supplier, and then allow water to stand in the bed for a period

adequate to allow entrapped gases to escape.

i. Gravel Mounding. Gravel mounding occurs when support gravel

is disrupted during the backwash cycle. The contractor should correct

this situation by overlaying the support gravel with a layer of high

density material such as ilmenite or garnet, or modify the backwash

process.

 j. Media Upset. Filter media can be upset (mixed) if the

backflow wash water rate is reduced to quickly.
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15 Jul 97

7.5-i

CHAPTER 7.5

CARBON ADSORPTION

Paragraph Page

7.5-1 GENERAL 7.5-1

a. Liquid Phase Carbon Adsorption 7.5-1

b. Vapor Phase Carbon Adsorption 7.5-1

7.5-2 PRODUCTS 7.5-1

a. Carbon Units 7.5-1

b. Carbon 7.5-1

7.5-3 EXECUTION 7.5-1

a. Piping 7.5-1

b. Liners 7.5-2

c. Air Release Valves 7.5-2

d. Vessel Finish 7.5-2

e. Safety Features 7.5-2

7.5-4 OPERATION AND MAINTENANCE 7.5-2

a. Plugged Media 7.5-2

b. Carbon Disposal 7.5-2

c. Regeneration 7.5-2

d. Biofouling 7.5-2

e. Breakthrough 7.5-3
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15 Jul 97

7.5-1

CHAPTER 7.5 CARBON ADSORPTION

7.5-1. GENERAL.

a. Liquid Phase Carbon Adsorption. Liquid phase carbon

adsorption is a technology in which water is pumped through a vessel

containing granular activated carbon (GAC) to which dissolved

contaminants adsorb (are removed from the water). Carbon is

“activated” for this purpose by processing the carbon to create porous

particles with a large internal surface area that attracts and adsorbs

organic molecules as well as certain metals and some inorganic

molecules. Carbon adsorption is effective at removing contaminants

to low concentrations. Commercial grades of granular activated carbon

(GAC) are available specifically for use in liquid applications. 

These carbons differ from the activated carbon used in vapor-phase

applications. When the concentration of contaminants adsorbed reaches

a certain level, the contaminants begin to leave (breakthrough) the

bed. At that time the carbon must be regenerated or replaced. 

b. Vapor Phase Carbon Adsorption. Vapor phase carbon

adsorption is a remedial technology in which pollutants are removed

from an air stream by physical adsorption onto activated carbon

grains. Commercial grades of activated carbon are available for

specific use in vapor phase applications. These carbons have a finer

pore structure and are more expensive than those used in liquid phase

carbon adsorption applications.

7.5-2. PRODUCTS.

a. Carbon Units. Carbon units are typically fabricated off

site and delivered ready for installation. Carbon vendors are

required to provide the proper piping configuration for the systems. 

Carbon adsorption units normally consist of one or more vessels filled

with carbon and connected in series or parallel. The vessels range in

size from large steel vessels that hold up to 20,000 pounds of

activated carbon to “55-gallon” drums. The large vessels are often

cylindrical tanks mounted horizontally or vertically. Some are

similar in shape to large garbage roll-off dumpsters. The large units

come as either skid mounted units which are ready to use or as

separate tanks that must be installed, piped, and filled with carbon. 

Small drums come filled with carbon but all piping and connections to

the contaminated air stream must be made on site. 

b. Carbon. 

(1) Check to ensure that the carbon type delivered to the

project is in conformance with the specification. 

(2) Check to see if regenerated carbon or virgin carbon is

specified for use. 

7.5-3. EXECUTION.

a. Piping. Some carbon vessels have the influent line at the

top and some at the bottom. Verify that the unit is piped correctly. 

The piping and valving are complex and can easily be installed

incorrectly. A detailed inspection is needed to assure the 
EP 415-1-261

15 Jul 97

7.5-2

installation is correct.

b. Liners. Ensure that the GAC vessel lining is as specified.

c. Air Release Valves. Ensure that air release valves in

liquid phase units are provided on the high points of the piping,

normally on the carbon piping skid. 

d. Vessel Finish. Verify that all scratches on the vessel

surface are repainted in accordance with the manufacturer’s

recommendation. 

e. Safety Features. Ensure that vapor phase carbon vessels are

equipped with pressure relief and internal fire suppression

(sprinklers) systems as shown on the plans and specifications.

7.5-4. OPERATION AND MAINTENANCE.

a. Plugged Media. Plugged media can be unplugged by back

washing. Recurring media plugging problems should be referred to the

supplier or the design district. 

b. Carbon Disposal. 

(1) A plan for off-site disposal or regeneration of carbon

should be established well before the carbon is spent. 

(a) A written disposal agreement with an EPA/state approved

disposal facility may be required. 

(b) Manifesting may also be required if the contaminants

adsorbed make the carbon a hazardous waste. Refer to EP 200-1-2 for

additional information on manifesting.

(2) Adsorption of some organic materials can cause the carbon

to ignite when exposed to air as it is removed for regeneration or

disposal. Determine whether the organic chemicals being adsorbed

present this problem before removing carbon from the vessel. If the

specifications do not address the potential for fires, contact the

design district or the carbon vendor before removing carbon from the

vessel. 

c. Regeneration. 

(1) Regeneration can be accomplished on or off site. It is

regenerated on site by steam desorption. It is regenerated off site

by thermal desorption. Regeneration is often carried out off site due

to economic constraints.

(2) Following breakthrough of a primary carbon column, a

secondary column is normally placed on line as the primary column

while the exhausted column is replaced. 

d. Biofouling. A potential operational problem associated with

granular activated carbon involves the growth of microorganisms on the

carbon bed. In some cases, this growth may become so prolific that

the differential pressure through the carbon bed becomes too great to

allow for efficient operation. The contractor, or operator, can

correct this problem through periodic “back-flushing” of the carbon

bed, or through pretreatment activities to destroy the microorganisms

in the influent. 
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15 Jul 97

7.5-3

e. Breakthrough. The contractor should supply the design

district with the predicted breakthrough time. The design district

will compare the predicted to the actual breakthrough time. If the

actual time of breakthrough is much less than the design, require the

contractor to determine the cause.
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15 Jul 97

7.6-i

CHAPTER 7.6

AIR STRIPPING

Paragraph Page

7.6-1 GENERAL 7.6-1

7.6-2 PRODUCTS 7.6-1

a. Packed Tower 7.6-1

b. Packing 7.6-1

c. Spray Nozzle 7.6-1

d. Demister 7.6-1

e. Blower 7.6-1

f. Insulation 7.6-1

7.6-3 EXECUTION 7.6-2

a. Hydraulic Testing 7.6-2

b. Welding 7.6-2

c. Permitting 7.6-2

d. Maintenance 7.6-2

7.6-4 OPERATION AND MAINTENANCE 7.6-2

a. Packing 7.6-2

b. Off-Gas Control 7.6-2 
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15 Jul 97

7.6-1

CHAPTER 7.6 AIR STRIPPING

7.6-1. GENERAL. Air stripping is a technology in which dissolved

volatile organic chemicals are removed from water by increasing the

surface area of the contaminated water exposed to air. This allows 

the volatile chemicals to escape into the air. It is also effective

for removing inorganic contaminants such as carbon dioxide and

ammonia. Air stripping is not effective for the removal of organic

contaminants with low volatility (low Henry’s Law constants). Henry’s

Law provides a means to estimate the tendency of a chemical to

volatilize from water. Examples of organic contaminants that easily

volatilize are BETX, TCE, DCE, and PCE. The types of air stripping

equipment commonly used are packed towers, diffused aerators, tray

aerators (low profile air strippers) and spray aerators. In most

cases, some type of treatment is required for the contaminated off gas

(air containing the volatiles). The typical packed tower air stripper

is filled with polypropylene packing that has a large surface area. 

The contaminated water is pumped to the top of the tower above the

packing and is sprayed onto the top of the packing with a spray nozzle

to distribute the contaminated water uniformly over the packing. A

forced air blower is located at the bottom of the column that forces

air up through the bed of packing at the same time the water is

“trickling” down through the packing (i.e. countercurrent flow). As

the water and air pass each other the volatiles in the water leave the

water (volatilize) and enter the air stream. The air stream then

carries the volatiles up and out of the top of the column. A sump at

the bottom of the tower collects the cleaned water. Auxiliary

equipment that can be added to the basic air stripper includes an air

heater to improve removal efficiencies, automated controls, explosion

proof components and off-gas treatment systems.

7.6-2. PRODUCTS. 

a. Packed Tower. The packed tower is typically made of steel

lined with a protective coating, aluminum or fiberglass. The tower is

mounted vertically on a concrete or similar base. Verify that the base

is constructed according to the specifications. The base must be able

to support the column if it should accidentally become filled with

water.

b. Packing. The packing usually has small open shapes and is

made of polypropylene. The packing is often delivered to the site in

cardboard boxes. The packing is dumped from the boxes into the top of

the column during construction.

c. Spray Nozzle. Spray nozzles or other devices are located at

the top of the column to distribute the water evenly over the top of

the packing.

d. Demister. A demister (mesh) fits at the top of the column

to remove the water mist from the air before the air leaves the top of

the column.

e. Blower. Blowers convey air through the air stripper.

 f. Insulation. Verify that insulation has been installed, if

required.
EP 415-1-261

15 Jul 97

7.6-2

7.6-3. EXECUTION.

a. Hydraulic Testing. Testing should be completed prior to

filling the tower with packing.

b. Welding. In the event the tower is constructed of steel or

a material that requires welding, do not allow welding on the tower

exterior when packing is in the tower. This may melt the packing.

c. Permitting. Determine if there are permitting and

monitoring requirements for the release of off gas. Verify there is

an approved emission monitoring plan to determine when breakthrough

occurs and carbon must be replaced or regenerated.

d. Maintenance. Replacement of column packing from the top of

the tower, or from elevated stacks, may cause safety concerns.

7.6-4. Operation and Maintenance.

a. Packing. 

(1) Operational concerns associated with air stripper towers

are normally directed towards maintenance of the packing material. 

(2) Check the packing material for evidence of fouling. 

Fouling reduces the air flow rate and increases the pressure drop

through the column. Fouling is caused by oxidation of dissolved

minerals (such as iron and manganese) in the feed water or by

precipitation of calcium carbonate. Biological growth on the packing

material can also result in fouling of the packing. This problem may

be remedied through periodic replacement of the packing media or

through acid washing of the media inside the tower. 

b. Off-Gas Control. 

(1) In the event vapor phase carbon is utilized for off-gas

control, verify that a heat exchanger has been installed ahead of the

carbon to adjust the humidity of the air stream entering the carbon to

approximately 50 percent or less. 

(2) The design district, or the design contractor, should be

asked to verify that the controls associated with the blower and offgas heater are coordinated with the air stripper and other unit

processes to allow for successful operation of the unit.
EP 415-1-261

15 Jul 97

7.7-i

CHAPTER 7.7

ULTRAVIOLET OXIDATION

Paragraph Page

7.7-1 GENERAL 7.7-1

7.7-2 PRODUCTS 7.7-1

a. Hydrogen Peroxide (H O ) 7.7-1 2 2

b. Ozone (O ) Generator 7.7-1 3

c. UV Reactor 7.7-1

7.7-3 EXECUTION 7.7-1

a. Interface 7.7-1

b. Cooling Loops 7.7-1

c. Off-Gas Control 7.7-1

d. Cooling Water 7.7-1

e. Hydrogen Peroxide 7.7-1

f. Air Handling 7.7-2

7.7-4 OPERATION AND MAINTENANCE 7.7-2
EP 415-1-261

15 Jul 97

7.7-1

CHAPTER 7.7 ULTRAVIOLET OXIDATION

7.7-1. GENERAL. Ultraviolet (UV) oxidation is a destructive process

that oxidizes organic chemicals and explosives in water by the

addition of ozone or hydrogen peroxide in the presence of UV light. 

If complete destruction is achieved, the final products are carbon

dioxide, water, and salts. Ozone is a gas that is generated on site

and bubbled into the waste water stream either immediately upstream of

or inside the enclosed reactor vessel containing the UV lights. 

Hydrogen peroxide is purchased as a liquid solution of 35 or 50

percent hydrogen peroxide mixed in water. This solution is pumped

into the waste water stream. If hydrogen peroxide is used as the

oxidant, it is fed into the waste stream before it enters the enclosed

reactor which houses the UV lights. A wide variety of organic and

explosive contaminants can be treated with UV oxidation, including

petroleum hydrocarbons, solvents, pesticides, and explosives such as

TNT, RDX and HMX. UV light, ozone and hydrogen peroxide are

hazardous, therefore, vendor information should be reviewed for safe

handling and operating procedures.

7.7-2. PRODUCTS.

a. Hydrogen Peroxide (H O ). Storage tank and pump 2 2

(if H O is used). 2 2

b. Ozone (O ) Generator. Unit that generates gaseous ozone from 3

atmospheric air.

c. UV Reactor. Unit containing UV light(s) in which the

organic materials are destroyed.

7.7-3. EXECUTION.

a. Interface. Ensure that the controls and interface required

between the UV oxidation system and other plant components are clearly

identified, and adhered to, per the contract specifications. 

b. Cooling Loops. When an ozone generator is supplied as part

of the process equipment, make sure that cooling loops are not run

through electrical circuitry, where condensate from the tubing can

lead to electrical shorts.

c. Off-Gas Control. If ozone is used as part of the treatment

package, off-gas control to destroy residual ozone is normally

provided. The off-gas control typically consists of a heated catalyst

bed. It is imperative that no condensate or water be allowed to

contact the catalyst bed since moisture destroys the integrity of the

catalyst. Ensure connecting piping slopes away from the unit. 

d. Cooling Water. If ozone is produced on site, water will be

required to cool the ozone generator. Verify that the contractor has

a permit for the discharge of the ozone generator cooling water (if

required).

e. Hydrogen Peroxide. Hydrogen peroxide storage is typically

handled like other process chemicals. Spill containment is normally

provided on the process floor. 
EP 415-1-261

15 Jul 97

7.7-2

f. Air Handling. When air handling is a system requirement,

ensure that the valving/dampening is provided according to

specifications.

7.7-4. OPERATIONS AND MAINTENANCE. The UV oxidation system will

require periodic replacement of ultraviolet bulbs, however, fouling of

the quartz sheaths that house the bulbs may also become a problem. 

Excessive fouling may require that the system be taken off line in

order to remove the encrusted material. 
EP 415-1-261

15 Jul 97

7.8-i

CHAPTER 7.8

CHEMICAL HANDLING AND SLUDGE MANAGEMENT

Paragraph Page

7.8-1 GENERAL 7.8-1

7.8-2 PRODUCTS 7.8-1

a. Chemicals 7.8-1

b. Chemical Metering Pumps 7.8-1

c. Chemical Feed Systems 7.8-1

d. Sludge Management 7.8-1

7.8-3 EXECUTION 7.8-1

a. Chemical Handling 7.8-1

b. Sludge Management 7.8-2
EP 415-1-261

15 Jul 97

7.8-1

CHAPTER 7.8 CHEMICAL HANDLING AND SLUDGE MANAGEMENT

7.8-1. GENERAL. Chemical handling and sludge management systems

typically consist of mixing and storage systems for the chemicals,

pumps, control systems, and piping.

7.8-2. PRODUCTS.

a. Chemicals. Treatment chemicals are one of the greatest

hazards associated with a ground water treatment facility. Material

safety data sheets for each chemical must be available at the site. 

The construction of suitable chemical handling systems is critical to

the safety of personnel during operation. Material requirements for

pumps, piping and storage systems must be carefully checked with the

specifications. In addition to the hazards associated with the

chemicals themselves, care must be exercised to prevent mixing of

chemicals due to chemical reactions which may occur. 

b. Chemical Metering Pumps. Chemical metering pumps should be

supplied with adequate turndown capacity to allow for varying flow

conditions. Capacity and materials of construction for pump internals

are critical to pump performance. Ensure that the specification has

been closely followed with respect to required internal components. 

c. Chemical Feed Systems. To the greatest extent possible, the

chemical feed system should be provided as a system with all

components coming from the same manufacturer. Each chemical has

unique equipment requirements with regard to sizing, materials of

construction, control, etc. Ensure that the specifications have been

closely followed with respect to using a single vendor.

d. Sludge Management. Sludge thickeners are typically used for

storage and thickening of sludge. Sludge thickeners are normally fed

using positive displacement diaphragm pumps or progressive cavity

pumps. Sludge generated from biological or metals precipitation

treatment processes requires some type of collection, pumping,

thickening/conditioning and dewatering. The goal of the sludge

management system is to reduce the sludge volume as much as possible

to reduce disposal costs. This is accomplished by dewatering the

sludge.

7.8-3. EXECUTION.

a. Chemical Handling.

(1) Safety. Operation of the chemical feed and storage system

is potentially the most hazardous activity for the plant operator. It

is imperative that all safety precautions of the material safety data

sheets for each chemical be closely followed. Personnel should wear

protective equipment and never work on chemical tanks and pipes alone. 

Water should never be added to concentrated acids or bases because

violent reactions may occur. However, concentrated acids or bases may

be added cautiously to water.

(2) Acid. Refer to the specifications for installation and

materials requirements. Acid piping requires special attention for

safety reasons. Ensure the contractor takes appropriate measures to 
EP 415-1-261

15 Jul 97

7.8-2

address the expansion and contraction that occurs over normal

temperature variations.

(3) Caustic. When 50 percent sodium hydroxide (caustic) is

utilized in northern climates, storage of the 50 percent caustic is a

concern due to potential freezing at relatively high temperatures (13

degrees C (55 degrees F)). The potential for freezing at these

temperatures will necessitate providing storage within the process

area, or provisions for heat tracing of the piping and heating of the

tank contents. 

(4) Lime. Lime is used to enhance the conditioning of sludge

in the sludge dewatering process and may also be used for pH

elevation. Hydrated lime is provided in a powder form, while

quicklime is usually provided in granular or nugget form. Quicklime

is normally used only in very large applications. When quicklime is

used, the grit produced during formation of lime slurry (slaking) must

be disposed of. Hydrated lime does not produce a grit requiring

disposal. Depending upon the size of the application and the lime

requirements, the lime may be stored in a silo or handled using bags. 

If a lime silo is required, the plans and specifications should be

carefully followed. If a carbon steel slurry mix tank is provided,

ensure that the interior of the tank is coated to prevent rusting. 

(5) Polymer. Polymer is utilized to assist in the

agglomerization of particles in solution and to reduce solids loading

on downstream processes. Polymer may come in powder or liquid (neat)

form. When polymer is mixed to the application strength (typically

one percent), the solution usually has a limited shelf life. When

spilled, polymers will present a slip hazard.

(6) Oxidants. As previously discussed, oxidants such as

hydrogen peroxide are used in a variety of applications within a

ground water treatment facility. Oxidants are very hazardous. Verify

that the procedures in the specifications regarding safe handling and

storage are followed closely.

(7) Chemical Piping. As a safety consideration, chemical

piping should not be run overhead without using a tray guard or other

method to capture the chemical in the event of a pipe rupture. If

this is not specified, contact the designer.

(8) Chemical Tank Requirements. Secondary containment is

typically provided around the chemical storage tanks in the event of

spills or a catastrophic failure of the primary storage tank. Tank

labels and material safety data sheets should be in place prior to

filling the tanks.

(9) Controls. The control system may be manual, on/off, or

proportional based on liquid level, flow, pH, ORP or other process

measurement. If tied to a supervision, control and data acquisition

(SCADA) system, ensure compliance with the provisions in the

specifications.

b. Sludge Management.

(1) Sludge Collection. Sludge accumulates in the bottom of

biological and metals precipitation treatment processes and is

periodically pumped to a sludge thickening and storage tank. The

design of the system is based upon a predicted sludge generation rate. 

However, it is ultimately up to the contractor/operator of the

facility, based upon the sludge accumulation and treatment 
EP 415-1-261

15 Jul 97

7.8-3

efficiency, to determine when and how often to pump sludge from the

treatment system. Typically, sludge sampling ports are provided on

the equipment to assist operators with the sludge pumping

determination. 

(2) Sludge Pumping. Sludge pumps are capable of pumping fluids

with high solids content. Sludge pumps are typically of the

pneumatically operated diaphragm type or progressive cavity type. 

Ensure that appropriate air quality (see manufacturers

recommendations) is used to operate diaphragm pumps. 

(3) Sludge Thickening/Conditioning. Sludge thickening on most

HTRW projects is usually a batch process. During the thickening and

conditioning, lime and/or polymer is added to enhance sludge

dewatering. The supernatant (water) from the sludge is usually

returned to the front of the treatment plant for further treatment. 

The contractor is required to optimize sludge thickening/conditioning

to maximize the solids content and minimize the volume of sludge

requiring dewatering. Efficient use of chemicals should also be

considered. Verify that access has been provided to remove the

internal mechanism of the sludge thickener for maintenance activities. 

Contact the design district if adequate access has not been provided.

(4) Sludge Dewatering. The contractor is responsible for

providing and operating some type of sludge dewatering system. This is

often a container where the sludge has time to settle further followed

by a plate and frame filter press to dewater the sludge.

(5) Sludge Dewatering Equipment. Sludge filter presses

mechanically "squeeze" the water from the sludge. Housekeeping is

normally a concern when operating a filter press. Hose bibs 

(spigots) should be provided near the sludge filter press to assist in

general cleanup. Verify that sufficient thought has been given to the

placement of the roll-off containers to be used to collect the

dewatered sludge. This is important to prevent spillage/over splash of

contaminated sludge material on to the ground. If not, contact the

design district. If a sludge dryer is utilized to further reduce the

water content in the sludge, be aware that the dryer tends to produce

large amounts of dust.

(6) Sludge Disposal. Options for off-site disposal of sludge

should be determined well in advance of the time for disposal. The

sludge may be classified as a hazardous waste. A written agreement

with an EPA/state approved disposal facility may be required. 

Manifesting may also be required. Refer to EP 200-1-2 for additional

information on manifesting.