EPA/540/R-02/506

December 2002 

Anaerobic Compost
 

Constructed Wetlands System
 

(CWS) Technology
 

Innovative Technology Evaluation Report
 

National Risk Management Research Laboratory
 

Office of Research and Development
 

U.S. Environmental Protection Agency
 

Cincinnati, Ohio 45268
 
Notice 

The information in this document has been funded by the U. S. Environmental Protection Agency (EPA) under Contract No. 

68-C5-0037 to Tetra Tech EM Inc. It has been subjected to the Agency's peer and administrative reviews and has been 

approved for publication as an EPA document. Mention of trade names or commercial products does not constitute an 

endorsement or recommendation for use. 

ii 
Foreword 

The U.S. Environmental Protection Agency is charged by Congress with protecting the Nation's land, air, and water 

resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions leading 

to a compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this 

mandate, EPA's research program is providing data and technical support for solving environmental problems today and 

building a science knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect our 

health, and prevent or reduce environmental risks in the future. 

The National Risk Management Research Laboratory is the Agency's center for investigation of technological and 

management approaches for reducing risks from threats to human health and the environment. The focus of the Laboratory's 

research program is on methods for the prevention and control of pollution to air, land, water and subsurface resources; 

protection of water quality in public water systems; remediation of contaminated sites and ground water; and prevention and 

control of indoor air pollution. The goal of this research effort is to catalyze development and implementation of innovative, 

cost-effective environmental technologies; develop scientific and engineering information needed by EPA to support 

regulatory and policy decisions; and provide technical support and information transfer to ensure effective implementation of 

environmental regulations and strategies. 

This publication has been produced as part of the Laboratory's strategic long-term research plan. It is published and made 

available by EPA's Office of Research and Development to assist the user community and to link researchers with their clients. 

Hugh W. McKinnon, Director
 

National Risk Management Research Laboratory
 

iii 
Abstract 

As part of the Superfund Innovative Technology Evaluation (SITE) Program, the U.S. Environmental Protection Agency (EPA) 

evaluated constructed wetlands systems (CWS) for removing high concentrations of zinc from mine drainage at the Burleigh 

Tunnel in Silver Plume, Colorado. 

Exploration geologists have known for many years that metals, most commonly copper, iron, manganese, uranium, and 

zinc, frequently accumulate in swamps and bogs located in mineralized areas. This understanding forms the basis for the 

design of CWS—essentially excavated pits filled with organic matter—that have been developed and constructed over the 

past 15 years to treat drainage from abandoned coal mines in the eastern United States. Mine drainage is routed through 

the organic material, where metals are removed through a combination of physical, chemical, and biological processes. 

In fall 1994, anaerobic compost wetlands in both upflow and downflow configurations were constructed adjacent to and 

received drainage from the Burleigh Tunnel, which forms part of the Clear Creek/Central City Superfund site. The 

systems were operated over a 3-year period. The effectiveness of treatment by the CWS was evaluated by comparing the 

concentration of zinc and other metals from corresponding influent and effluent analyses. By far the dominant toxic metal 

present in the drainage was zinc. The upflow CWS removed an average of 93 percent of the zinc during the first year of 

operation, and 49 and 43 percent during the second and third years. The downflow CWS removed an average of 77 

percent of zinc during the first year and 70 percent during the second year. (Flow was discontinued to the downflow 

system in the third year.) 

iv 
Contents 

List of Figures and Tables ........................................................................................................................... viii
 

Acronyms, Abbreviations, and Symbols ....................................................................................................... ix
 

Conversion Factors ........................................................................................................................................ xi
 

Acknowledgments ......................................................................................................................................... xii
 

Executive Summary ........................................................................................................................................ 1
 

1 Introduction ............................................................................................................................................. 5
 

1.1 Brief Description of the SITE Program and Reports ...................................................................... 5
 

1.2 Purpose of the Innovative Technology Evaluation Report .............................................................. 6
 

1.3 Technology Description ................................................................................................................... 6
 

1.3.1 Treatment Technology .......................................................................................................8 
 

1.3.2 System Components and Function .................................................................................... 8
 

1.3.3 Key Features of the CWS Technology .............................................................................. 9
 

1.4 Key Contacts ................................................................................................................................... 11
 

2	 Technology Application Analysis ......................................................................................................... 12
 

2.1 Applicable Wastes .......................................................................................................................... 12
 

2.2 Factors Affecting Performance ...................................................................................................... 12
 

2.2.1 Mine Drainage Characteristics ........................................................................................ 12
 

2.2.2 Operating Parameters ...................................................................................................... 13
 

2.2.3 Compost Performance ...................................................................................................... 13
 

2.3	 Site Characteristics ......................................................................................................................... 13
 

2.3.1 Support Systems ............................................................................................................... 13
 

2.3.2 Site Area, Preparation, and Access ................................................................................. 15
 

2.3.3 Climate ............................................................................................................................. 15
 

2.3.4 Utilities ............................................................................................................................. 15
 

2.3.5 Services and Supplies ...................................................................................................... 15
 

2.4 Availability, Adaptability, and Transportability of Equipment .................................................... 15
 

2.5 Material Handling Requirements ................................................................................................... 16
 

2.6 Personnel Requirements ................................................................................................................. 16
 

2.7 Potential Community Exposures .................................................................................................... 16
 

2.8 Evaluation of Technology Against RI/FS Criteria ........................................................................ 16
 

2.9 Potential Regulatory Requirements ............................................................................................... 18
 

v 
Contents (continued)
 

2.9.1 Comprehensive Environmental Response, Compensation, and Liability Act ............... 18
 

2.9.2 Resource Conservation and Recovery Act ...................................................................... 18
 

2.9.3 Clean Water Act .............................................................................................................. 19
 

2.9.4 Occupational Safety and Health Act ............................................................................... 19
 

2.10Limitations of the Technology ....................................................................................................... 19
 

3	 Treatment Effectiveness ........................................................................................................................ 22
 

3.1 Background ..................................................................................................................................... 22
 

3.2 Review of SITE Demonstration ..................................................................................................... 22
 

3.2.1 Treatability Study ............................................................................................................. 22
 

3.2.2 Technology Demonstration .............................................................................................. 23
 

3.2.3 Operational and Sampling Problems and Variations from the Work Plan ................... 23
 

3.2.4 Site Demobilization ......................................................................................................... 24
 

3.3	 Demonstration Methodology .......................................................................................................... 24
 

3.3.1 Testing Approach ............................................................................................................. 25
 

3.3.2 Sampling, Analysis, and Measurement Procedures ........................................................ 25
 

3.4	 Site Demonstration Results ............................................................................................................ 27
 

3.4.1 Burleigh Mine Drainage Chemistry ................................................................................ 27
 

3.4.2 Downflow CWS ............................................................................................................... 27
 

3.4.3 Upflow CWS .................................................................................................................... 36
 

3.4.4 Clear Creek ...................................................................................................................... 40
 

3.4.5 Toxicity Testing Results .................................................................................................. 40
 

3.4.6 Microbial Toxicity Testing .............................................................................................. 42
 

3.5 Attainment of Demonstration Objectives ...................................................................................... 43
 

3.6 Design Effectiveness ...................................................................................................................... 44
 

3.6.1 Downflow Cell ................................................................................................................. 44
 

3.6.2 Upflow Cell ...................................................................................................................... 45
 

4 Data Quality Review .............................................................................................................................. 46
 

4.1	 Zinc Data Quality Review .............................................................................................................. 46
 

4.1.1 Quality Assurance Results for Field Sampling Activities .............................................. 46
 

4.1.2 Quality Assurance Results for Sample Analysis ............................................................. 47
 

4.2 Acute Toxicity Data Quality Review ............................................................................................. 48
 

4.2.1 Analytical Quality Assurance .......................................................................................... 48
 

4.3 Noncritical Parameters Data Quality Review ................................................................................ 50
 

5 Economic Analysis ................................................................................................................................ 52
 

vi
Contents (continued)
 

5.1 Basis of Economic Analysis ........................................................................................................... 52
 

5.2	 Cost Categories ............................................................................................................................... 53
 

5.2.1 Site Preparation Costs ...................................................................................................... 53
 

5.2.2 Permitting and Regulatory Requirements ....................................................................... 53
 

5.2.3 Capital Equipment ........................................................................................................... 53
 

5.2.4 Startup .............................................................................................................................. 55
 

5.2.5 Labor ................................................................................................................................ 55
 

5.2.6 Consumables and Supplies .............................................................................................. 55
 

5.2.7 Utilities ............................................................................................................................. 55
 

5.2.8 Residual Waste Shipping and Handling ......................................................................... 55
 

5.2.9 Analytical Services .......................................................................................................... 55
 

5.2.10 Maintenance and Modifications ...................................................................................... 55
 

5.2.11 Demobilization ................................................................................................................. 56
 

6 Technology Status ................................................................................................................................. 57
 

7 References .............................................................................................................................................. 58
 

Appendix 

A Analytical Results Summary Tables 

B Case Study 

vii 
Figures 

1 Site Location ............................................................................................................................................ 3
 

2 Schematic Cross-Section of an Anaerobic CWS Upflow Cell .............................................................. 5
 

3 Flow Rates Measured for Effluent Cells ............................................................................................... 17
 

4 CWS Zinc Concentration by Month ..................................................................................................... 21
 

5 CWS Cadmium Concentration by Month ............................................................................................. 23
 

6 CWS Lead Removal by Month ............................................................................................................. 24
 

7 CWS Manganese Removal by Month ................................................................................................... 25
 

8 Sulfate-Reducing Bacteria, Downflow CWS Substrate ........................................................................ 27
 

9 Monthly Zinc Loading, Downflow CWS .............................................................................................. 29
 

10 Sulfate-Reducing Bacteria, Upflow CWS Substrate ............................................................................. 32
 

11 Monthly Zinc Loading, Upflow CWS ................................................................................................... 33
 

Tables 

1 Evaluation of CWS Treatment Versus RI/FS Criteria ......................................................................... 11
 

2 Treatment Standards and Influent concentrations for the CWS SITE Demonstration ....................... 13
 

3 Summary of Standard Methods and Procedures ................................................................................... 20
 

4 Average Downflow CWS Substrate Results ......................................................................................... 26
 

5 Average Upflow CWS Substrate Results .............................................................................................. 31
 

6 Clear Creek Upstream ........................................................................................................................... 35
 

7 Clear Creek Downstream ...................................................................................................................... 35
 

8 CWS Demonstration Toxicity (LC50) Results ....................................................................................... 36
 

9 CWS Costs for Different Treatment Flow Rates .................................................................................. 47
 

viii
 
Acronyms, Abbreviations, and Symbols 

oC Degrees Celsius
 

oF Degrees Fahrenheit
 

%C Percent completeness
 

%R Percent recovery
 

AA Atomic absorption
 

ARAR Applicable or relevant and appropriate requirement
 

ASTM American Society for Testing and Materials
 

AVS Acid volatile sulfide
 

BOD Biochemical oxygen demand
 

CDPHE Colorado Department of Public Health and Environment
 

CDM Camp, Dresser, & McKee, Inc.
 

CFU Colony forming units
 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
 

CFR Code of Federal Regulations
 

CWS Constructed wetlands system
 

DQO Data quality objective
 

Eh Oxidation reduction potential
 

EPA U.S. Environmental Protection Agency
 

FS Feasibility study
 

gpm Gallons per minute
 

H2

S Hydrogen sulfide
 

HDPE High-density polyethylene
 

HSWA Hazardous and Solid Waste Amendments of 1984
 

ICP Inductively coupled plasma
 

ITER Innovative technology evaluation report
 

LC Lethal concentration for 50 percent of the test organisms 50 

MCAWW Methods for Chemical Analysis of Water and Wastes
 

MCL Maximum contaminant level
 

μg Micrograms
 

ix 
Acronyms, Abbreviations, and Symbols (continued)
 

μS Microsiemens
 

mg/kg Milligrams per kilogram
 

mg/L Milligrams per liter
 

MS Matrix spike
 

NCP National Oil and Hazardous Substances Pollution Contingency Plan
 

NIST National Institute of Standards and Technology
 

NPDES National Pollutant Discharge Elimination System
 

NRMRL National Risk Management Research Laboratory
 

O&M Operation and maintenance
 

ORD Office of Research and Development
 

ORP Oxidation/reduction potential
 

OSHA Occupational Safety and Health Administration
 

OSWER Office of Solid Waste and Emergency Response
 

PPE Personal protective equipment
 

ppm Parts per million
 

PRC PRC Environmental Management, Inc.
 

PVC Polyvinyl chloride
 

QAPP Quality assurance project plan
 

QA/QC Quality assurance/quality control
 

RCRA Resource Conservation and Recovery Act
 

RI Remedial investigation
 

RPD Relative percent difference
 

SARA Superfund Amendments and Reauthorization Act
 

SITE Superfund Innovative Technology Evaluation
 

SDWA Safe Drinking Water Act
 

SOP Standard operating procedure
 

SRM Standard reference material
 

SWDA Solid Waste Disposal Act
 

TCLP Toxicity characteristic leaching procedure
 

TOC Total organic carbon
 

TDS Total dissolved solids
 

TSS Total suspended solids
 

yd3 Cubic yards
 

x 
Conversion Factors
 

To Convert From To Multiply By 

Length inch 

foot 

mile 

centimeter 

meter 

kilometer 

2.54 

0.305 

1.61 

Area: square foot 

acre 

square meter 

square meter 

0.0929 

4,047 

Volume: gallon 

cubic foot 

liter 

cubic meter 

3.78 

0.0283 

Mass: pound kilogram 0.454 

Energy: kilowatt-hour megajoule 3.60 

Power: kilowatt horsepower 1.34 

Temperature: (°Fahrenheit - 32) °Celsius

xi 

0.556
Acknowledgments 

This report was prepared under the direction of Mr. Edward Bates, the U.S. Environmental Protection Agency (EPA) Superfund 

Innovative Technology Evaluation (SITE) project manager at the National Risk Management Research Laboratory (NRMRL) 

in Cincinnati, Ohio; Ms. Dana Allen, U.S. EPA Region VIII; and Mr. James Lewis, Colorado Department of Public Health 

and Environment. This report was prepared by Mr. Gary Miller, Mr. Garry Farmer, Mr. Jon Bridges, and Ms. Shaleigh 

Whitesell of Tetra Tech EM Inc. (Tetra Tech) and Mr. Mark Kadnuck of the Colorado Department of Public Health and 

Environment (formerly of Tetra Tech). This report was typed by Ms. Robin Richey and Ms. June Diller, edited by Mr. Butch 

Fries, and reviewed by Dr. Kenneth Partymiller of Tetra Tech. 

This project consisted of a demonstration conducted under the SITE program to evaluate the anaerobic compost Constructed Wetland System (CWS) technology developed by the Colorado Department of Public Health and Environment 

(CDPHE). The technology demonstration was conducted on mineral mine drainage at the Burleigh Tunnel in Silver 

Plume, Colorado, which is included in the Clear Creek/Central City Superfund site. Passive treatment was selected as the 

preferred treatment alternative for the Burleigh Tunnel drainage in a 1991 Record of Decision (ROD). This Innovative 

Technology Evaluation Report (ITER) interprets the data that was collected during the nearly four-year demonstration and 

discusses the potential applicability of the technology. 

The cooperation and participation of the following people are gratefully acknowledged: Mr. Vincent Gallardo, Ms. Ann 

Vega, and Dr. James Lazorchek of NRMRL; Ms. Holly Fliniau of EPA Region VIII and Mr. Rick Brown of CDPHE. 

xii 
Executive Summary

This executive summary of the Constructed Wetlands 

System (CWS) technology demonstration discusses 

technology applications, describes system effectiveness, 

and presents an evaluation of the costs associated with the 

system and lessons learned during the field demonstration. 

Introduction 

The anaerobic compost CWS technology was evaluated 

under the Superfund Innovative Technology Evaluation 

(SITE) program. The SITE program was developed by 

the U.S. Environmental Protection Agency (EPA) in 

response to the mandate of the Superfund Amendments 

and Reauthorization Act (SARA) of 1986. The primary 

purpose of the program is to maximize the use of alternative 

treatment technologies. To this end, reliable performance 

and cost data on innovative technologies are developed 

during demonstrations where the technology is used to 

treat a specific waste. 

After the demonstration, EPA publishes an Innovative 

Technology Evaluation Report (ITER) designed to aid 

decision makers in evaluating the technology for further 

consideration as an appropriate cleanup option. This 

ITER includes a review of the technology application, an 

economic analysis of treatment costs, and the results of 

the demonstration. 

For this demonstration, wetlands were designed and 

constructed to treat mine drainage through a combination 

of physical, chemical, and biological processes. The mine 

drainage, containing primarily zinc contamination, flowed 

into the constructed wetlands where metals were removed 

by sorption, precipitation, and biological sulfate reduction. 

The demonstration included the evaluation of two CWS 

treatment cells (pits) filled with an organic-rich compost 

(96 percent) and alfalfa hay (4 percent) mixture. Both 

treatment cells were constructed adjacent to, and received 

drainage from, the Burleigh Tunnel in Silver Plume, 

Colorado. The Burleigh Tunnel is part of the Clear Creek/ 

Central City Superfund site. Passive wetlands treatment 

was identified by the Colorado Department of Public 

Health and Environment (CDPHE) as the preferred 

remedial alternative for the Burleigh Tunnel drainage. 

Each treatment cell covered 0.05 acres and differed in 

flow configuration. One cell was constructed in an upflow 

configuration, in which water entered from the base of the 

cell and was forced upward to discharge; the other was 

constructed in a downflow configuration, in which water 

entered from the top of the cell and flowed by gravity to 

discharge. The compost and hay mixture was 4 feet deep 

in both cells. Flow rates of water into and out of the cells 

were controlled by a series of v-notch weirs; each cell 

was designed to treat 7 gallons per minute (gpm). 

Technology Applications Analysis 

The primary objectives of the CWS technology 

demonstration were to (1) measure the reduction of zinc 

in Burleigh Tunnel drainage resulting from the CWS 

treatment with respect to cell configuration and seasonal 

variation (temperature); (2) assess the toxicity of the 

Burleigh Tunnel drainage; (3) characterize the toxicity 

reduction resulting from treatment of the drainage by the 

CWS; and (4) estimate toxicity reductions in the stream 

(Clear Creek) receiving the Burleigh Tunnel drainage. 

CWS treatment effectiveness was evaluated by comparing 

the concentration of zinc and other metals from 

corresponding CWS influent and effluent analyses 

(see Section 3.0). The results indicate the concentration 

of zinc in the Burleigh Tunnel drainage ranged from 50 to 

60 milligrams per liter (mg/L) during the first year of the 

demonstration. However, in May and June 1995, a great 

deal of spring snow and rain and a rapid thaw combined 

to increase the amount of runoff entering the mine 

network drained by the Burleigh Tunnel. At that time, 

1 
flow from the tunnel increased from 45 gpm to more than 

300 gpm, and zinc concentrations increased from 55 mg/ 

L (April 12, 1995) to 109 mg/L (August 8, 1995). Over 

the final 2 years of the demonstration, zinc concentrations 

in Burleigh Tunnel mine drainage were lower in the 

winter, dropped again in April or May when flow through 

the mine workings increased, and rapidly increased in 

summer, remaining high throughout the fall. During this 

period, Burleigh Tunnel mine drainage zinc concentrations 

generally remained between 45 and 84 mg/L, with 

increases to more than 100 mg/L noted during the late 

summer and fall. The Burleigh Tunnel drainage is also 

characterized by moderate pH and alkalinity and low 

concentrations of metals other than zinc. 

Downflow 

In the first year of operation, CDPHE reported the 

downflow cell developed flow problems on occasion, 

preventing treatment of the intended amount of water. 

Remedies, such as fluffing the compost, were tried and 

were somewhat successful allowing the system to flow at 

4 to 6 gpm during the first two years of operation. During 

the third year, the flow in this cell dropped to less than 

1 gpm and flow to this cell was discontinued. 

The permeability loss is believed to be related to 

precipitation of metal oxides, hydroxides, and carbonates, 

settling of fine materials in the cell, and compaction of the 

substrate material. 

In general, the downflow cell was effective in removing 

zinc during the first year of operation. Zinc removal by this 

cell ranged from 69 to 96 percent with a mean removal of 

77 percent. During the second year of operation, zinc 

removal ranged from 62 to 79 percent with a mean of 70 

percent. During the final 6 months of operation, flow 

through the downflow cell continued to decline increasing 

the residence time of the mine drainage in the cell. The 

increased residence time improved zinc removal. Zinc 

removal during this period ranged from 67 to 93 percent 

with a mean of 82 percent. 

Aqueous geochemical modeling, observations of cell 

compost, sulfate-reducing bacteria count results, and acid 

volatile sulfide data suggest that biological sulfate reduction 

is not the primary zinc removal mechanism within this cell. 

Instead, the primary metal removal mechanism is thought 

to be the precipitation of zinc oxides, hydroxides, and 

carbonates in aerobic sections of the downflow cell. 

Upflow 

During the first 6 months of operation, upflow cell effluent 

samples contained low (less than 1 mg/L) concentrations 

of zinc. However, during the later part of 1994 and into 

1995, upflow cell effluent zinc concentrations began to 

increase. The concentrations of zinc ranged from 0.13 mg/ 

L in early 1994 to 60.1 mg/L in May 1997. 

In the spring of 1995, heavy spring runoff overwhelmed 

the CWS system, channeling 20 gpm of aerobic water 

(nearly three times the design flow) through the upflow 

cell. This high runoff also apparently mobilized more zinc 

from the mine workings or mine waters and substantially 

increased the concentration of zinc in the mine drainage. 

The large flows created aerobic conditions and the 

increased zinc loading had a detrimental effect on the 

upflow cell. These new conditions apparently initiated a 

change in the cell’s microbial ecology. After the high flow 

event, the upflow cell removed only 50 to 60 percent of the 

zinc in the mine drainage. Prior to the high flow event, the 

upflow cell removed greater than 90 percent of the zinc 

contamination (year 1 mean removal was 93 percent). 

The loss of substrate hydraulic conductivity also affected 

the upflow CWS. During the demonstration, the height of 

the influent wier was periodically raised to increase the 

hydraulic pressure to maintain flow through the upflow 

CWS. The water level was raised approximately 1 foot 

over the 4-year demonstration. In 1997, this cell developed 

a visibly obvious preferential pathway in the southeast 

corner, adjacent to the bermed sidewall. This preferential 

pathway was eliminated by terminating flow to this section 

of the wetland through excavating of the wetland substrate 

to allow installation of a cap on the influent line. 

The high initial zinc removal rates in the upflow cell were 

likely the result of absorption of metals and biological 

sulfate reduction. The decline in metal removal by the 

upflow cell after the high flow event is likely related to the 

decline in sulfate reducing bacteria in this cell. There are 

several possible reasons for the decline of the sulfatereducing bacteria including toxicity produced by high zinc 

concentrations for the bacteria, prolonged exposure to 

aerobic conditions allowing other wetland bacteria to 

outcompete the sulfate-reducing bacteria, or the utilization 

of all the most readily metabolized growth materials by the 

sulfate reducing bacteria leading to lower activity and 

eventually lower populations of these bacteria. Ultimately, 

the primary metal removal mechanism over the last 

several years of the demonstration was likely chemical 

precipitation. 

2 
Economic Analysis 

An economic analysis was conducted to examine 11 cost 

categories for the CWS technology. The 11 categories 

include (1) site preparation; (2) permitting and regulatory 

requirements; (3) capital equipment and construction; 

(4) startup; (5) labor; (6) consumables and supplies; 

(7) utilities; (8) residual and waste shipping and handling; 

(9) analytical services; (10) maintenance and 

modifications; and (11) demobilization. 

A number of factors affect the estimated costs of treating 

mine drainage with the CWS technology. These factors 

generally include flow rate, type and concentration of 

contaminants, water chemistry, physical site conditions, 

site location, and treatment goals. In addition, the 

characteristics of the spent compost produced by a CWS 

will affect disposal costs since the compost may require 

treatment for off-site disposal. 

Based on the criteria evaluated in the cost analysis, the 

average estimated cost for a constructed wetland at 

50 gallons per minute (gpm) over a 15-year period is 

$1,744,100 million or $0.0045 per gallon of water treated. 

Treatment Effectiveness 

Based on this demonstration, the following conclusions 

may be drawn about the effectiveness of the anaerobic 

compost CWS technology. 

• The upflow CWS removed an average (arithmetic

mean) of 53 mg/L (93 percent) of zinc during the

first year of operation. 

• Upflow cell zinc removal averaged 41 mg/L

(49 percent) during the second year and 30 mg/L

(43 percent) during the third year of operation. 

• During the first year of operation, the upflow cell

effluent was not toxic to Ceriodaphnia dubia or

Pimephales promelas. 

• The downflow CWS removed an average of 44.2 mg/

L (77.4 percent) of zinc during the first year and 58

mg/L (70 percent) during the second year of

operation. 

• The CWS is relatively easy to construct with readily

available materials. 

In summary, results from this SITE demonstration and 

additional tests of the CWS technology suggest that the 

CWS is capable of reducing the toxicity of contaminated 

mine drainage by removing metals such as zinc, cadmium, 

iron, lead, nickel, and silver. 

However, the results of this demonstration also clearly 

show that an anaerobic compost CWS using sulfate 

reduction may have difficulty in recovering from upset 

conditions such as the high flow event that occurred 

during this demonstration. 

In addition, application of this technology to mine drainage 

containing high concentrations of iron may require 

pretreatment to remove the iron. If not removed, the iron 

could precipitate in the wetland and could lead to loss of 

wetland permeability. 

Lessons Learned 

The following items highlight lessons learned during the 

CDPHE constructed wetlands demonstration. The list is 

partitioned among five categories of considerations (or 

concerns): theory, design, construction, operation and 

maintenance, and analytical. 

Theory 

• An upflow CWS using biological sulfate reduction is

capable of reducing the concentration of several

metals including zinc, cadmium, nickel, lead, iron, and

silver. The extent of metal reduction depends on the

concentration of the metal and sulfate in the mine 

drainage, and the performance of the CWS. 

• The primary metal removal process in the downflow

CWS did not appear to be biological sulfate reduction.

Zinc in the demonstration CWS downflow cell 

appeared to be primarily removed by chemical

precipitation. Generally, zinc removal by the

demonstration downflow cell ranged between 70 and 

80 percent. However, the accumulation of zinc 

carbonate in the cell compost may have attributed to

a loss of cell permeability during the demonstration. 

Design 

• A hydraulic residence time of 50 hours (estimated)

provided good metal removal in the upflow cell

during the first 8 months of the demonstration.

However, the decline in metal removal after this 

initial period and inability to re-establish the sulfatereducing bacteria in the upflow cell suggest this

residence time may be a lower limit for mine drainages

containing high metal concentrations. 

• Hydraulically, the upflow cell performed well with

4 feet of compost. However, some short circuiting

was observed after 3 years of operation. 

• The mixture of fresh compost (96 percent) and

hay (4 percent) used as a substrate during the

demonstration was a superior environment for sulfatereducing bacteria. However, the compost contains

high levels of ammonia that is readily leached during 

3 
wetland startup, resulting in elevated levels of

ammonia in the discharge. The addition of wood

products to the substrate can reduce the amount of

ammonia generated. Land treatment has been used 

at some sites to dispose of wetland startup discharge. 

• Each wetland cell should have an easily adjustable

influent conveyance with the capability of bypassing

200 to 300 percent of typical peak flows. 

Construction 

• Bermed sidewalls lined with high-density polyethylene

(HDPE) is a suitable construction technique for cold

region applications. However, the use of a geonet

on the wetland surface to allow animals and people

to walk on the wetland is not recommended. The 

geonet did not allow additional compost or hay to be

added to the wetland. In addition, the use of geofabric

to separate the piping networks from the compost is

not recommended. 

• Effluent collection pipes (polyvinyl chloride [PVC])

should be larger than 1 inch in diameter to prevent

clogging from precipitated material. In addition, the 

effluent collection structure should include cleanouts 

that allow precipitated material to be periodically

removed without driving the precipitate back into the

wetland compost. 

• Lining a downflow cell with HDPE above the level

of the ponded water allows this water to short circuit

the wetland compost. Short circuits are most 

noticeable during the winter when the compost

becomes frozen and contracts from the liner, creating

a gap between the compost and liner. 

Operation and Maintenance 

• Constructed wetlands can require frequent inspections

to ensure that proper flows are maintained within the

treatment cells. However, properly designed and

constructed influent distribution and effluent collection 

networks may reduce inspection frequency. 

• Treatment system downtime with CWS treatment is

not high. Effluent piping networks should be cleaned

out periodically (once or twice a year was appropriate

for the Burleigh Tunnel CWS). The frequency of

compost removal and replacement will depend on

contaminant loading, metal removal efficiencies, and

the desired performance level of the CWS. Compost

removal and replacement frequency for the

demonstration CWS upflow cell is estimated to be

once every 4 to 5 years. 

• Straw bales covered with insulated construction 

blankets (used to cure concrete in cold weather) are

an effective insulator for an upflow CWS during

winter operation. However, their use requires an

upper support structure such as a geonet. An 

equally effective insulation system could include 

6 inches of fresh compost and hay covered by

construction blankets, although this system has not

been tested. 

• Straw bales used for winter insulation must not be 

allowed to become saturated by water. Their 

combined weight will compress the wetland compost,

making it impermeable. 

Analytical 

• Routine (monthly) total metals analysis in

conjunction with quarterly dissolved metals analysis

were useful in evaluating the performance of the

CWS. The mine drainage and effluents were 

sampled and analyzed every 2 weeks during the first

2 years of the demonstration; however, monthly

sampling (conducted over the final year of the

demonstration) is adequate to track treatment

performance. 

• Routine aquatic toxicity testing of the mine drainage

and CWS effluent also provides useful water quality

information. During the CWS demonstration, these

analyses were conducted every 3 to 4 months, but

semi-annual analyses could also be used.

Demonstration aquatic toxicity testing used two test

organisms, fathead minnows (Pimephalus promelas)

and water fleas (Ceriodaphnia dubia); however, other

test organisms including trout fry could also be used. 

• Sulfate-reducing bacteria analyses of wetland

compost were conducted monthly during the first 2

years of the CWS demonstration. These analyses,

while useful, did not show much variation until the 

high flow event, and their frequency could easily be

reduced to every other month or even a quarterly.

Acid volatile sulfide analysis can indicate the

accumulation of metal sulfides within the CWS 

compost; however, the compost sample must be

collected from the area of metal filtration. The acid 

volatile sulfide analysis procedure is not routine for

most laboratories, and meaningful results may not be

achievable. 

• All aqueous field analyses conducted during the

CWS demonstration including pH, Eh (effluent),

dissolved oxygen (influent), conductivity, and

temperature were useful measurements. It should 

be noted that the platinum element of the Eh probe is

prone to poisoning, requiring periodic replacement. 

4 
Section 1

Introduction

This section provides background information about the 

SITE program, discusses the purpose of this ITER, and 

describes the CWS technology. Key contacts for additional 

information about the SITE program, this technology, and 

the demonstration site are listed at the end of this section. 

1.1 Brief Description of the SITE

Program and Reports 

SARA mandates that EPA select, to the maximum extent 

practicable, remedial actions at Superfund sites that create 

permanent solutions (as opposed to land-based disposal) 

for contamination that affects human health and the 

environment. In response to this mandate, the SITE 

program was established by EPA’s Office of Solid Waste 

and Emergency Response (OSWER) and Office of 

Research and Development (ORD). The SITE program 

promotes the development, demonstration, and use of 

new or innovative technologies to clean up Superfund 

sites across the country. 

The SITE program’s primary purpose is to maximize the 

use of alternatives in cleaning up hazardous waste sites by 

encouraging the development and demonstration 

of innovative treatment and monitoring technologies. It 

consists of the Demonstration Program, the Emerging 

Technology Program, the Monitoring and Measurement 

Technologies Program, and the Technology Transfer 

Program. These programs are discussed in more detail 

below. 

The objective of the Demonstration Program is to develop 

reliable performance and cost data on innovative treatment 

technologies so that potential users may assess specific 

technologies. Technologies evaluated either are currently 

or will soon be available for remediation of Superfund 

sites. SITE demonstrations are conducted at hazardous 

waste sites under conditions that closely simulate fullscale remediation, thus assuring the usefulness and 

reliability of information collected. Data collected are 

used to assess the performance of the technology, the 

potential need for pre- and post-treatment processing of 

wastes, potential operating problems, and approximate 

costs. The demonstrations also allow evaluation of longterm risks and operating and maintenance (O&M) costs. 

The Emerging Technology Program focuses on 

successfully proven, bench-scale technologies that are in 

an early stage of development involving pilot-scale 

or laboratory testing. Successful technologies are 

encouraged to advance to the Demonstration Program. 

The constructed wetlands is an example of a successful 

graduate of the Emerging Technology Program that was 

evaluated in the Demonstration Program. 

Existing technologies that improve field monitoring and 

site characterization are identified in the Monitoring and 

Measurement Technologies Program. New technologies 

that provide faster, more cost-effective contamination 

and site assessment data are supported by this program. 

The Monitoring and Measurement Technologies Program 

also formulates the protocols and standard operating 

procedures for demonstrating methods and equipment. 

The Technology Transfer Program disseminates technical 

information on innovative technologies in the 

Demonstration, Emerging Technology, and Monitoring 

and Measurement Technologies Programs through various 

activities. These activities increase the awareness and 

promote the use of innovative technologies for assessment 

and remediation of Superfund sites. The goal of technology 

transfer is to promote communication among remedial 

managers requiring up-to-date technical information. 

Technologies are selected for the SITE Demonstration 

Program through annual requests for proposals. ORD 

staff review the proposals, including any unsolicited 

proposals that may be submitted throughout the year, to 

determine which technologies show the most promise for 

use at Superfund sites. Technologies chosen must be at 

5 
the pilot- or full-scale stage, must be innovative, and must 

have some advantage over existing technologies. Mobile 

technologies are of particular interest. Once EPA has 

accepted a proposal, cooperative agreements between 

EPA and the technology developer establish responsibilities 

for conducting the demonstrations and evaluating the 

technology. The developer is responsible for demonstrating 

the technology at the selected site and is expected to pay 

any costs for transportation, operation, and removal of 

equipment. EPA is responsible for project planning, site 

preparation, sampling and analysis, quality assurance and 

quality control (QA/QC), and for preparing reports, 

disseminating information, and transporting and disposing 

of untreated and treated waste material. For the CWS 

evaluation, CDPHE (the lead agency of the Burleigh 

Tunnel site) identified passive wetlands treatment as the 

preferred treatment alternative with agreement by EPA 

and the division of responsibilities was essentially as 

described. 

The results of the CWS technology demonstration are 

published in two documents: the SITE technology capsule 

and the present ITER. The SITE technology capsule 

provides relevant information on the technology, 

emphasizing key features of the results of the SITE field 

demonstration. The ITER is discussed in the following 

section. Both the SITE technology capsule and the ITER 

are intended for use by remedial managers making a 

detailed evaluation of the technology for a specific site and 

waste. 

1.2 Purpose of the Innovative

Technology Evaluation Report 

The ITER provides information on the CWS technology 

and includes a comprehensive description of the 

demonstration and its results. The ITER is intended for 

use by EPA remedial project managers, EPA on-scene 

coordinators, contractors, and other decision makers for 

implementing specific remedial actions. The ITER is 

designed to aid decision makers in evaluating specific 

technologies for further consideration as an option in a 

particular cleanup operation. This report represents a 

critical step in the development and commercialization of 

a treatment technology. To encourage the general use of 

demonstration technologies, EPA provides information 

regarding the applicability of each technology to specific 

sites and wastes. Therefore, the ITER includes information 

on cost and site-specific characteristics. It also discusses 

advantages, disadvantages, and limitations of the 

technology. Each SITE demonstration evaluates the 

performance of a technology in treating a specific waste. 

The waste characteristics at other sites may differ from 

the characteristics of the treated waste. Therefore, 

successful field demonstration of a technology at one site 

does not necessarily ensure that it will be applicable at 

other sites. Data from the field demonstration may 

require extrapolation for estimating the operating ranges 

in which the technology will perform satisfactorily. Only 

limited conclusions can be drawn from a single field 

demonstration. 

1.3 Technology Description 

The Colorado Department of Public Health and 

Environment submitted a proposal to the SITE program 

for demonstrating the anaerobic compost CWS technology. 

This technology was selected for a SITE demonstration at 

the Burleigh Tunnel in Silver Plume, Colorado. The 

demonstration was carried out under a cooperative 

agreement involving the EPA National Risk Management 

Research Laboratory (NRMRL), CDPHE, and EPA 

Region 8. 

The Burleigh Tunnel is located approximately 50 miles 

west of Denver in the Silver Plume - Georgetown mining 

district (Figure 1), within the Clear Creek/Central City 

Superfund site. The Silver Plume - Georgetown mining 

district occupies an area of about 25 square miles 

surrounding the towns of Silver Plume and Georgetown. 

The tunnel entrance is at an elevation of 9,152 feet, about 

400 feet north of Clear Creek, on the western side of the 

town of Silver Plume. The area immediately surrounding 

the tunnel entrance is littered with mill tailings and waste 

rock dumps. Dilapidated buildings and equipment 

from previous milling operations are also present. 

No mining operations are active in the immediate area. 

The water draining from the Burleigh Tunnel is of nearneutral pH (ranging from 6.9 to 7.9) and has high zinc 

concentrations (ranging from 44.8 to 109 mg/L). The 

drainage also contains moderate alkalinity and low levels 

of metals other than zinc. 

A treatability study was conducted at the Burleigh Tunnel 

between June 18, 1993 and August 12, 1993. The 

treatability study involved the construction, operation, and 

sampling of two upflow compost and hay bioreactors that 

treated mine drainage from the Burleigh Tunnel. The 

treatability study (PRC 1993) showed that low levels of 

sulfate in the mine drainage would not limit biological 

sulfate reduction, thereby permitting the removal of zinc 

and other metals by the bioreactors or the demonstration 

scale treatment cells. Construction of the CWS 

demonstration cells began in August 1993 and was 

6 
7

Figure 1. Site location.
completed in November 1993. The demonstration began 

in January 1994 and continued for a 46-month period 

through November 1997. Evaluation of the CWS 

technology is based on results of the treatability study and 

the SITE demonstration at the Burleigh Tunnel site. 

1.3.1 Treatment Technology 

There are generally three types of constructed wetlands: 

free-water surface systems, subsurface flow systems, 

and aquatic plant systems (EPA 1988). A free-water 

system typically consists of shallow basins or channels 

with slow- flowing water and plant life. A subsurface 

flow wetland consists of basins or channels filled with 

permeable substrate material; the water flows through, 

rather than over, this substrate. An aquatic plant system 

is essentially a free water surface system with deeper 

channels containing floating or suspended plants. In 

general, free-water surface and aquatic plant systems are 

aerobic wetlands that remove metals primarily by aerobic 

oxidation of iron followed by precipitation of iron hydroxides, 

that leads to the precipitation or adsorption of other 

metals. Aerobic wetlands are most successful in removing 

iron, arsenic, selenium and, to some extent, manganese 

from moderately low to neutral pH mine waters (Gusek 

and others 1994). 

Anaerobic compost wetlands are designed to treat mine 

drainage through a combination of physical, chemical, and 

biological processes. Mine drainage is directed into 

constructed wetlands that contain an organic-rich compost 

substrate. Initially, sorption to the CWS substrate is the 

primary metal removal mechanism active within the 

system. Sorption includes adsorption of metals to organic 

and inorganic wetlands materials and absorption of metals 

into wetlands microorganisms and plants. 

• Adsorption refers to the binding of positively charged

ions to mineral surfaces by metal cations in solution.

The sorption of inorganic ions is largely determined

by complex chemical equilibria involving the charge

and size of the element or complex ion, the nature of

the sorbing material, and the pH of the aqueous

solution. The properties of the surface that influence

inorganic sorption include net surface charge and the

presence, configuration, and pH dependence of

binding sites. The structure of the solid may also

affect adsorption reactions. 

• Absorption refers to the incorporation of ions 

or compounds into the cell structure of

microorganisms or plants. Metals may also be

incorporated into the structure of complex humic

substances formed during the degradation of the

substrate. 

After several months, the sorption capacity of the wetlands 

is exhausted and metal removal efficiencies by this 

mechanism decline. 

Once the sorption capacity of the CWS substrate is 

expended, the formation, precipitation, and filtration of 

metal sulfides become the primary metal removal 

mechanism in the CWS. The process is believed to be 

biologically mediated by sulfate-reducing bacteria present 

in anaerobic zones within the CWS. 

The bacteria oxidize organic matter provided by the 

wetland with the simultaneous reduction of sulfate to 

hydrogen sulfide. The hydrogen sulfide reacts with 

dissolved metals to produce metal sulfides. The metal 

sulfides, with low aqueous solubilities, precipitate and 

become trapped in the wetlands substrate by filtration. 

The following reactions illustrate the overall oxidation/ 

sulfate reduction reactions and subsequent formation of 

metal sulfides. 

- SO4

-2 + 2CH2

O —› HS- + 2HCO3 + H+ 

M+2 + H2S or HS- —› MS(s) + 2H+ 

where: M is a metal such as zinc (Zn+2), iron (Fe+2), nickel 

(Ni+2), and (s) indicates a solid. 

In addition, other reactions within the wetlands may 

contribute to observed metal removal, including mineral 

precipitation and chelation (binding) to suspended organic 

material. In general, mine drainage contains low levels of 

dissolved oxygen that, when exposed to air, will take up 

oxygen and become aerobic. This process can lead to 

geochemical disequilibrium where the metal is no longer 

soluble at this concentration and may initiate metal 

precipitation. Zinc carbonate (Smithsonite) is an example 

of a mineral that may precipitate in the demonstration 

downflow CWS. In addition, the decay of wetland 

compost and biomass will produce dissolved and suspended 

organic material in the wetland pore water. These 

materials can chelate metals in solution. Although chelated 

metals may not be effectively removed (filtered) by the 

wetland, they may not be available biochemically to 

aquatic plants and organisms exposed to the effluent. 

1.3.2 System Components and Function 

Two CWS treatment cells were located adjacent to the 

Burleigh Tunnel between a compressor building and an 

old mill. Each cell covered 0.05 acre; the two cells 

differed in flow configuration. The cell nearest the mine 

8 
adit was an upflow system, in which water entered the cell 

under pressure from the bottom and flowed upward 

through the substrate material to discharge. The second 

cell was a downflow system, in which the water entered 

the cell from the top and flowed by gravity to the bottom 

for discharge. The demonstration CWS cells were highly 

engineered systems compared to many of the previously 

tested constructed wetlands, including the Big 5 wetlands 

evaluated in the Emerging Technology Program (EPA/ 

540/R-93/523). Figure 2 shows a cross-section schematic 

of the upflow CWS treatment cell. The downflow cell 

was identical except the direction of mine drainage flow 

in the compost is reversed. 

Both CWS treatment cells were installed below grade to 

reduce freezing of the cells during winter. Both had 

bermed earthen side walls. The base of each cell was 

made up of a gravel subgrade, a 16-ounce geofabric, a 

sand layer, a clay liner, and a high density polyethylene 

liner. The base was separated from the influent or 

effluent piping by a geonet. A 7-ounce geofabric separated 

the perforated PVC piping from the compost. The compost 

was held in place with a combination of 7-ounce geofabric 

and geogrid in the upflow cell. The perforated effluent 

piping was also supported by the geogrid in the upflow cell. 

Up to 6 inches of dry substrate material was located above 

the perforated piping. The geonet and the perforated 

piping ensured even distribution of the influent water into 

the treatment cells and prevented short circuiting of water 

through the cells. The influent and effluent distribution 

piping were also staggered horizontally as an additional 

precaution against short circuiting. 

Existing construction near the Burleigh Tunnel entrance 

required that the upflow cell be 10 percent smaller by 

volume than the downflow cell. The dimensions of the 

cells are as follows: 

• Upflow cell - 69 feet long, 25.5 feet wide, and 4 feet

deep, with an estimated total substrate volume of

198 cubic yards 

• Downflow cell - 62 feet long, 33 feet wide, and 4

feet deep, with an estimated total substrate volume

at 218 cubic yards 

Note: The dimensions listed are at the top of the cell 

wall. The volumes listed take into account the sloped 

walls of the cells. 

The organic-rich compost substrate was composed of a 

mixture of 95 to 96 percent manure compost and 4 to 

5 percent hay. The compost was produced from cattle 

manure and unidentified paper products. The compost 

and hay mixture had been identified as the most effective 

medium in removing zinc from the drainage during the 

previous bench-scale test (Camp, Dresser and McKee 

1993). Wood based substrates have also been used in 

constructed wetland systems. 

The flow to the CWS cells was regulated by a series of 

concrete v-notch weirs, one for the influent and one for 

the effluent of each cell. The effluent weir controlled the 

flow and the hydraulic residence time of the mine drainage 

through both CWS cells. Each cell was designed for a 

flow of 7 gpm with a total flow capacity for the two cells 

of 14 gpm. The remaining flow from the Burleigh Tunnel 

drainage was diverted to Clear Creek (untreated) via the 

influent weir. A drainage collection structure was 

constructed within the Burleigh Tunnel to build sufficient 

hydraulic head to drive the flow through the two CWS. 

1.3.3 Key Features of the CWS 

Technology 

Certain features of the CWS technology allow it to be 

adapted to a variety of settings: 

• The hardware components (geosynthetic materials,

PVC piping, and flow control units) of the CWS are

readily available. 

• Compost materials can be composed of readily

available materials. However, the actual composition

of a substrate material for a site-specific constructed

wetland is best determined through pilot studies.

Composted manure was used during this study. 

• Operation and maintenance costs are low since the

systems are generally self-contained, requiring only

periodic changes of the compost depending on sitespecific conditions. 

Other features that should be thoroughly evaluated before 

constructing a CWS include the following: 

• Properties of the drainage to be treated. Some 

drainages may need some type of pretreatment

before entering the CWS. For example, drainage

with high iron or aluminum content might prematurely

clog the CWS if not pretreated to remove some of

the metal. 

• Climate conditions must be evaluated to assess the 

potential for reduced efficiency of the system during

different seasons of the year. 

• Contingencies if the system does not perform as

expected. 

9 
Figure 2. Schematic cross-section of an anaerobic CWS upflow cell. 

10 
• Proximity to a populated area—odors generally are

associated with CWS treatment. 

• Land availability near the source of the contaminated

water to avoid extended transport. The CWS 

typically requires more land than a conventional 

treatment system. Consequently, locations with

steep slopes and drainages would make construction

more difficult and costly. 

• Cost of constructing the system if substrate and

other materials are not readily available. 

• Possible use of concrete basins to eliminate 

replacement costs for liners. 

• Potential for vandalism of the CWS, which could 

result in increased costs. 

• Seasonal fluctuation of water flow or chemistry and

the potential impact to the CWS. 

• Production and release of nutrients from substrate 

and stream standard requirements for discharge of

produced nutrients 

1.4 Key Contacts 

Additional information on the CWS technology, the SITE 

program, and the demonstration site can be obtained from 

the following sources: 

The CWS Technology 

James Lewis

Colorado Department of Public Health and Environment

HMWMD-RP-82

4300 Cherry Creek Drive South

Denver, Colorado 80222-1530

Telephone: (303) 692-3390

Fax: (303) 759-5355

The SITE Program 

Edward Bates, Project Manager

U.S. Environmental Protection Agency

National Risk Management Research Laboratory

26 West Martin Luther King Drive

Cincinnati, Ohio 45268

Telephone: (513) 569-7774

Fax: (513) 569-7676

The Clear Creek/Central City Superfund Site 

Michael Holmes, Remedial Project Manager

U.S. Environmental Protection Agency

Region 8

999 18th Street, Suite 300

Denver, Colorado 80202

Telephone: (303) 312-6607

11 
Section 2
 

Technology Applications Analysis
 

This section of the ITER describes the general applicability 

of the CWS technology to contaminated waste sites. The 

analysis is based primarily on the SITE CWS treatability 

study and demonstration results. A detailed discussion 

of the treatability study and demonstration results is 

presented in Section 3.0 of this report. An article containing 

a constructed wetlands case study is presented in 

Appendix B. 

2.1 Applicable Wastes 

Constructed wetlands have been demonstrated to be 

effective in removing organic, metal, and nutrient elements 

including nitrogen and phosphorus from municipal 

wastewaters, mine drainage, industrial effluents, and 

agricultural run-off. The technology is waste-stream 

specific, requiring characterization of all organic and 

inorganic constituents. 

Because constructed wetlands can treat a wide variety of 

wastes, they vary considerably in their design. Constructed 

wetlands can be simple, single-cell systems, such as the 

two cells evaluated during this demonstration, or complex 

multicell or multicomponent systems. Complex constructed 

wetlands may include multiple wetland cells in series, 

anoxic limestone drains, marshes, ponds, and rock filters. 

Constructed wetlands tested in the eastern U.S. to 

remediate slightly acidic coal mine drainage have 

incorporated an anoxic limestone drain to provide alkalinity, 

followed by a holding pond, a constructed wetland, a 

shallow marsh, and finally a rock filter. The holding pond 

and wetland promote precipitation of iron hydroxides, 

while the marsh and rock filter remove manganese and 

suspended solids. Constructed wetlands design criteria 

are discussed in detail in an article by Gusek and Wildeman 

(1995). 

The results of the CWS demonstration (see Section 3.0) 

suggest the primary metals removal mechanisms are not 

identical within the upflow and downflow wetland cells. 

In the upflow cell, biological sulfate reduction appeared 

to be the primary zinc removal mechanism. Metals 

shown to be removed by this process include cadmium, 

copper, iron, lead, nickel, silver, and zinc (PRC 1995). In 

addition, biological sulfate reduction may also remove 

cobalt, mercury, and molybdenum contamination. In the 

downflow cell, chemical precipitation appeared to be the 

primary zinc removal mechanism. Because of the 

numerous geochemical species and complex equilibria 

involved in wetlands treatment of mine drainage, it is often 

difficult to predict which metals will precipitate. 

An equilibrium aqueous geochemical wetlands model 

(MINTEQ.AK) has been developed to help predict metal 

removal by constructed wetlands (Klusman 1993). 

2.2 Factors Affecting Performance 

Because CWS designs are so diverse, the number of 

parameters affecting their operation is also large. In the 

discussion that follows, the performance factors described 

pertain to this demonstration CWS (anaerobic compost) 

or to similar systems treating metal-contaminated mine 

drainage. These performance factors may or may not be 

relevant to constructed wetlands designed to treat organic 

or inorganic (nonmetal) contamination. Several factors 

influenced the performance of the two demonstration 

CWS. These factors can be grouped into three categories: 

(1) mine drainage characteristics, (2) operating parameters, 

and (3) compost degradation. 

2.2.1 Mine Drainage Characteristics 

The CWS technology is capable of treating a range of 

contaminated waters containing heavy metals. However, 

the effectiveness of a CWS can be reduced as 

contaminants in high concentrations precipitate and clog 

the system prematurely. Often, contaminated coal mine 

drainages in the eastern U.S. contain elevated 

concentrations of iron or aluminum. When the pH of these 

drainages is raised during wetland treatment, iron and 

12 
aluminum hydroxides can form and precipitate (Hedin and 

others 1994). 

These precipitates can lead to a loss of permeability or a 

gradual filling of the wetland. Because sulfate-reducing 

bacteria cannot survive in low pH environments, low pH 

mine drainage can also affect the ability of the biological 

sulfate reduction wetland to remove contaminants. The 

oxidation/reduction potential (ORP) of the mine drainage 

may also affect the performance of the constructed 

wetland. However, the extent of the ORP effect is 

unknown. 

2.2.2 Operating Parameters 

The operating parameters that can be adjusted during the 

treatment process include the flow rate and hydraulic 

residence time of water within the wetland. In general, 

the selection and design for the hydraulic residence time 

is a function of the rate of metal loading. A hydraulic 

residence time of 50 to 100 hours was found to work well 

in the biological sulfate reduction reactors used during the 

short-term CWS treatability study (Figure 3). 

The residence time in the upflow and downflow cells 

during the demonstration was calculated at between 50 

and 60 hours. The calculation was based on the substrate 

volume of the wetlands, the percent moisture of the 

substrate (generally, 50 to 65 percent with 50 percent used 

in the calculation), and a flow rate of 7 gpm. 

Maintaining proper hydraulic residence times is one of the 

most important factors in successful wetlands treatment. 

In biological-based systems, a short residence time may 

not allow metals to precipitate and be filtered out by the 

wetland or may expose the bacteria to inhibitory levels of 

metal contaminants. Both may result in lower metal 

removal rates. In chemical precipitation systems, 

compounds that precipitate slowly may not be removed to 

the same extent as rapidly precipitating compounds. 

Chemical amendments, such as alkalinity or nutrients, are 

also examples of parameters that can be adjusted during 

the wetland treatment process. Alkalinity may be added 

via an anoxic limestone drain or directly to the mine 

drainage as lime. Nutrients could also be added directly 

to the mine drainage or applied to the ponded surface 

water of downflow cells. Neither alkalinity nor nutrients 

was added to the SITE demonstration CWS. 

2.2.3 Compost Performance 

Compost performance depends on the compost materials 

used and the characteristics of the mine drainage. When 

using manure compost, the metals concentrations of the 

drainage, the nutrient concentrations in the compost, and 

gradual breakdown and compaction of the compost 

materials are the most important factors controlling compost 

effectiveness. Of these factors, substrate breakdown 

and compaction that leads to a loss of hydraulic conductivity 

is probably the most important factor. The breakdown of 

the complex biological polymers to smaller compounds by 

fermentative bacteria gradually destroys the structural 

intensity of the compost and leads to compaction. One 

way to extend substrate lifetime is to include materials that 

are degraded at a moderate rate. Based on the loss of 

nutrients and hydraulic conductivity in the upflow CWS, 

the wetland compost material is expected to last 4 to 

5 years before becoming ineffective. 

The accumulation of metals within the constructed wetlands 

may eventually cause the compost material to become a 

hazardous waste, substantially decreasing the number of 

compost disposal options and increasing treatment costs. 

However, after 4 years of near-continuous operation of 

the demonstration CWS, neither cell’s compost material 

developed hazardous characteristics based on thresholds 

defined in 40 Code of Federal Regulations (CFR) 

Part 261.24. However, the primary contaminant in the 

Burleigh Mine Drainage, zinc is not a TCLP analysis 

parameter. 

2.3 Site Characteristics 

Site characteristics are important when considering CWS 

technology because they can affect system application. 

All characteristics should be considered before selecting 

the technology to remediate a specific site. Site-specific 

factors include support systems, site area and preparation, 

site access, climate, hydrology, utilities, and the availability 

of services and supplies. 

2.3.1 Support Systems 

If on-site facilities are not already available, a small 

storage building equipped with electricity may be desirable 

near the treatment system. The on-site building could be 

used for storing operating and sampling equipment (tools, 

field instrumentation, and health- and safety-related gear) 

and providing shelter for sampling personnel during 

inclement weather. The building may also be used for 

calibrating field equipment for system monitoring. 

13 
14

Figure 3. Flow rates measured for effluent cells.
2.3.2 Site Area, Preparation, and Access 

Constructed wetlands typically require a larger level 

area compared to other treatment options. The results 

of this investigation suggest that a 50-60 hour hydraulic 

residence time is near the lower limit required of these 

systems to provide consistent metal removal. Researchers 

in this field have suggested that longer residence times 

ranging from 75 to 150 hours may be required for longterm metal removal (Dr. Ronald Klusman and Dr. Richard 

Gammons, personal communications) The depth of the 

compost in the demonstration CWS cells was 4 feet. The 

maximum depth of compost that can be used while 

maintaining treatment effectiveness is unknown. 

Consequently, some sites may require extensive grading 

and leveling to allow construction of a CWS. Depending 

on the site, grading and leveling may be cost prohibitive. 

Piping or other mechanisms for conveying mine drainage 

to the wetlands is also necessary. In addition, a relatively 

constant rate of flow is desired to keep the wetlands 

active. Thus, site conditions may require a mine 

drainage collection, storage, and distribution structure. 

Furthermore, an upflow constructed wetland may require 

that the mine drainage distribution network include a dam 

or pump to maintain sufficient hydraulic head to force 

the mine drainage through the compost. Also, piping is 

required to bypass flow around the wetland. This bypass 

piping or conveyance should be oversized to manage 

200 to 300 percent of the predicted maximum mine 

drainage discharge. 

Access roads for heavy equipment (excavation and 

hauling) are required to install, operate, and maintain a 

CWS. 

2.3.3 Climate 

The climate at potential constructed wetland sites can be 

a limiting factor. Extended periods of severe cold, 

extreme hot and arid conditions, and frequent severe 

storms or flooding will affect system performance. 

Extreme cold can freeze portions of the wetland resulting 

in channeling of the mine drainage through the substrate, 

thus, reducing the hydraulic residence time. In addition, 

cold temperatures may reduce microbial activity or 

populations. Reductions in hydraulic residence time and 

microbial activity will both lessen the ability of the 

constructed wetland to remove metals and may require it 

to be oversized. The large water surface areas and plant 

life associated with wetlands enhance evaporation and 

evapotransportation. A constructed wetland in a hot and 

arid climate may periodically dry up at a site with low 

water flow rates. If the wetland design does not consider 

cyclical periods of wet and dry, it may be less effective 

during the wet periods. Constructing wetlands in areas 

with frequent flooding or severe storms can lead to 

hydraulic overloading or washout of substrate materials. 

The engineering controls required to overcome these 

climatic or geographic limitations may eliminate the low 

cost and low maintenance advantages that make 

constructed wetlands appealing. 

2.3.4 Utilities 

The CWS is a passive treatment technology, so utilities 

are not required to operate the system. However, in some 

situations electricity for pumps or on-site analytical 

instrumentation may be desirable. In remote areas, an onsite storage building should be provided if possible. A 

telephone connection or cellular phone is required for 

operating and sampling personnel to contact emergency 

services if needed and for routine communications. 

2.3.5 Services and Supplies 

The main services required by the CWS are periodic 

adjustment of system flow rates, cleanout of effluent 

piping, and the removal and replacement of compost 

materials. During the CWS demonstration, flow rate 

adjustments were required every 3 to 6 months, and effluent 

piping cleanout was conducted once. However, both 

CWS demonstration cells were operated from a single vnotch weir and the flow diverted to the cells. The 

frequency of flow adjustment would be lower if each cell 

had been constructed with its own weir. The time 

between changeout of wetland compost depends on the 

chemical constituents of the influent water, the 

configuration and capacity of the constructed wetland, 

and the preferred method of disposal. The compost 

lifetime, estimated from nutrient loss and the development 

of short circuiting during this demonstration is estimated to 

be 4 to 5 years. 

2.4	 Availability, Adaptability, and

Transportability of Equipment 

The components of a simple CWS are generally available 

locally. The components include standard construction 

materials for the structure of the wetland cells, liner 

materials available from several sources, and compost 

materials, the type of which will depend on the contaminants 

in the mine drainage. The most suitable compost for a 

given application can be identified during a treatability 

study using materials available locally. 

15 
2.5 Material Handling Requirements 

The CWS generates spent compost material. Substrate 

material will require testing to evaluate disposal options. 

Depending on the disposal option, dewatering or other 

pretreatment may be necessary prior to shipment for offsite disposal. Depending on regulatory requirements, the 

effluent water generated during dewatering may also 

require additional treatment prior to discharge. 

Some CWS compost materials may contain high levels of 

water-soluble nitrogen or phosphorus compounds. These 

compounds can be readily leached from the fresh compost 

during startup of the constructed wetland. Thus, the CWS 

effluent at startup may require treatment to reduce or 

remove excess nitrogen or phosphorous. Treatment may 

include land application, if permitted, or effluent collection 

for subsequent recycling through the CWS. 

2.6 Personnel Requirements 

Wetlands construction and compost replacement require 

heavy equipment operators, laborers, and a construction 

supervisor. After the CWS is installed, personnel 

requirements include a sampling team and personnel to 

adjust system flow rates. Sampling personnel should be 

able to collect water and substrate samples for laboratory 

analysis and measure field parameters using standard 

instrumentation. 

All personnel should have completed an Occupational 

Safety and Health Administration (OSHA) initial 40-hour 

health and safety training course with annual 8-hour 

refresher courses, if applicable, before constructing, 

sampling, replacing compost, or removing a constructed 

wetland at hazardous waste sites. They should also 

participate in a medical monitoring program as specified 

under OSHA requirements. 

2.7 Potential Community Exposures 

Fencing and signs should be installed around a CWS to 

restrict access to the system for both humans and wildlife. 

The potential routes of exposure include the mine drainage 

or waste stream, the compost material, and the CWS 

effluent. The actual exposure risk depends on the 

constituents of the specific waste being treated and the 

effectiveness of the treatment. 

The CWS may also generate low concentrations of 

hydrogen sulfide gas, depending on the time of year and 

the biological activity of the CWS. Odors caused by 

hydrogen sulfide and volatile fatty acids from the decaying 

manure may be a nuisance to a local community. 

2.8	 Evaluation of Technology Against

RI/FS Criteria 

EPA has developed nine evaluation criteria to fulfill 

the requirements of the Comprehensive Environmental 

Response, Compensation, and Liability Act (CERCLA), 

as well as additional technical and policy considerations 

that have proven important for selecting potential remedial 

alternatives. These criteria serve as the basis for 

conducting bench-scale testing during the remedial 

investigation (RI) at a hazardous waste site, for conducting 

the detailed analysis during the feasibility study (FS), and 

for subsequently selecting an appropriate remedial action. 

Each SITE technology is evaluated against the nine EPA 

criteria because these technologies may be considered as 

potential remedial alternatives. The nine evaluation criteria 

are: 

•	 Overall protection of human health and the

environment 

•	 Compliance with applicable or relevant and

appropriate requirements (ARAR) 

• Long-term effectiveness and permanence 

• Reduction of toxicity, mobility, or volume 

• Short-term effectiveness 

• Implementability 

• Cost 

• State acceptance 

• Community acceptance 

Table 1 presents the results of this evaluation for the 

CWS. The demonstration results indicate the upflow 

CWS can provide short-term protection of the environment; 

reduces contaminant mobility, toxicity, and volume; is cost 

effective; implementable, and is an acceptable remedy to 

the community and state regulators. However, neither 

CWS cell tested in this demonstration, provided long-term 

effectiveness. This in part is the result of low zinc 

discharge requirements (200 μg/L) at the demonstration 

site. Other sites may have less strict discharge 

requirements. In addition, the upset condition resulting 

from the high flow event also contributed to the lack of 

long-effectiveness particularly in regards to the upflow 

cell. 

16 
Table 1. Evaluation of CWS Treatment Versus RI/FS Criteria 

Criterion Discussion cussion 

1. Overall Protection of Human Health 

and the Environment 

2. Compliance with Applicable or 

Relevant and Appropriate 

Requirements (ARAR) 

3. Long-Term Effectiveness and 

Permanence 

4. Short-term Effectiveness 

5. Reduction of Toxicity, Mobility, or 

Volume of contaminates through 

Treatment 

6. Implementability 

7. Cost 

8. Community Acceptance 

9. State Acceptance 

As tested, the CWS provided only short-term 

effectiveness. In different circumstances, the CWS may 

provide short- and long-term protection by removing 

mine drainage contaminants. 

Substrate is a recycled product, not mined or 

manufactured. 

Wetland effluent discharge may require compliance with 

Clean Water Act regulations. 

Substrate disposal may require compliance with RCRA 

regulations. 

CWS treatment removes contamination from mine 

drainage, but may not meet low-level discharge 

requirements. 

Use of CWS treatment with other technologies may be 

effective in meeting low-level discharge requirements. 

Presents few short-term risks to workers, community, or 

wildlife. 

Minimal personal protective equipment required for 

operators. 

CWS treatment reduces contaminant mobility, toxicity, 

and volume. 

Generally a passive treatment system, but can be 

active. 

Construction uses standard material and practices 

common in the industry. 

Construction cost of full-scale (50gpm) system is 

estimated at approximately $290,000. 

O&M of full-scale CWS system is estimated to be 

$57,000 per year. 

The public usually views the technology as a natural 

approach to treatment; therefore, the public generally 

accepts this technology. 

CDPHE found the technology shows promise for 

treating AMD; however, based on constraints at the 

Burleigh site, including the cold climate and proximity to 

town, CDPHE recommended not implementing a fullscale, permanent system at the site. 

Colorado Division of Minerals has built several CWSs to 

treat AMD. 

17 
2.9 Potential Regulatory Requirements 

This section discusses specific environmental regulations 

pertinent to operation of a CWS, including the transport, 

treatment, storage, and disposal of wastes and treatment 

residuals, and analyzes these regulations in view of the 

demonstration results. State and local regulatory 

requirements, which may be more stringent, must also be 

addressed by remedial managers. 

ARARs include the following: (1) CERCLA; (2) the 

Resource Conservation and Recovery Act (RCRA); 

(3) the Clean Water Act; and (4) OSHA regulations. 

These four general ARARs are discussed below; specific 

ARARs must be identified by remedial managers for each 

site. 

2.9.1	 Comprehensive Environmental

Response, Compensation, and

Liability Act 

CERCLA, as amended by SARA, authorizes the federal 

government to respond to releases or potential releases of 

any hazardous substance into the environment, as well as 

to releases of pollutants or contaminants that may present 

an imminent or significant danger to public health and 

welfare or the environment. 

As part of the requirements of CERCLA, EPA has 

prepared the National Oil and Hazardous Substances 

Pollution Contingency Plan (NCP) for hazardous substance 

response. The NCP, codified at 40 CFR Part 300, 

delineates methods and criteria used to determine the 

appropriate extent of removal and cleanup for hazardous 

waste contamination. 

SARA amended CERCLA and directed EPA to: 

•	 Use remedial alternatives that permanently and

significantly reduce the volume, toxicity, or mobility

of hazardous substances, pollutants, or contaminants. 

•	 Select remedial actions that protect human health

and the environment, are cost-effective, and involve 

permanent solutions and alternative treatment or

resource recovery technologies to the maximum

extent possible. 

•	 Avoid off-site transport and disposal of untreated

hazardous substances or contaminated materials when 

practicable treatment technologies exist (Section

121[b]). 

In general, two types of responses are possible under 

CERCLA: removals and remedial actions. The CWS 

technology is likely to be part of a CERCLA remedial 

action. Remedial actions are governed by CERCLA as 

amended by SARA. As stated above, these amendments 

promote remedies that permanently reduce the volume, 

toxicity, and mobility of hazardous substances, pollutants, 

or contaminants. 

On-site remedial actions must comply with federal and 

state ARARs. ARARs are identified on a site-by-site 

basis and may be waived under six conditions: (1) the 

action is an interim measure, and the ARAR will be met 

at completion; (2) compliance with the ARAR would pose 

a greater risk to human health and the environment than 

noncompliance; (3) it is technically impracticable to meet 

the ARAR; (4) the standard of performance of an ARAR 

can be met by an equivalent method; (5) a state ARAR 

has not been consistently applied elsewhere; and (6) 

ARAR compliance would not provide a balance between 

the protection achieved at a particular site and demands 

on the Superfund for other sites. These waiver options 

apply only to Superfund actions taken on site, and 

justification for the waiver must be clearly demonstrated. 

2.9.2	 Resource Conservation and 

Recovery Act 

RCRA, an amendment to the Solid Waste Disposal Act 

(SWDA), was enacted in 1976 to address the problem of 

safe disposal of the enormous volume of municipal and 

industrial solid waste generated annually. RCRA 

specifically addressed the identification and management 

of hazardous wastes. The Hazardous and Solid Waste 

Amendments of 1984 (HSWA) greatly expanded the 

scope and requirements of RCRA. 

The presence of RCRA-defined hazardous waste 

determines whether RCRA regulations apply to the 

CWS technology. RCRA regulations define and regulate 

hazardous waste transport, treatment, storage, and disposal. 

Wastes defined as hazardous under RCRA include 

characteristic and listed wastes. Criteria for identifying 

characteristic hazardous wastes are included in 40 CFR 

Part 261 Subpart C. Listed wastes from nonspecific and 

specific industrial sources, off-specification products, spill 

cleanups, and other industrial sources are itemized in 40 

CFR Part 261, Subpart D. 

The CWS demonstration treated mine discharge water 

from the Burleigh Tunnel, which is included in the Clear 

Creek/Central City Superfund site. The manure compost 

was tested regularly to determine whether it would become 

a hazardous waste during the demonstration. The concern 

18 
was that sorption and precipitation of metals could cause 

the substrate to become a hazardous waste, thus restricting 

options and increasing cost for material disposal. The 

substrate did not exhibit the characteristics of hazardous 

waste after nearly 4 years of operation. 

2.9.3 Clean Water Act 

The objective of the Clean Water Act is to restore and 

maintain the chemical, physical, and biological integrity of 

the nation’s waters. To achieve this objective, effluent 

limitations of toxic pollutants from point sources were 

established. Wastewater discharges are most commonly 

controlled through effluent standards and discharge permits 

administered through the National Pollutant Discharge 

Elimination System (NPDES) by individual states with 

input from the federal EPA. Under this system, discharge 

permits are issued with limits on the quantity and quality 

of effluents. These limits are based on a case-by-case 

evaluation of potential environmental impacts and on 

wasteload allocation studies aimed at distributing discharge 

allowances fairly. Discharge permits are designed as an 

enforcement tool with the ultimate goal of achieving 

ambient water quality standards (Metcalf and Eddy 1979). 

NPDES permit requirements must be evaluated for each 

CWS when the effluent water is discharged into a 

waterway or water body. The requirements and standards 

that must be met in the effluent for each CWS will be 

based on the waterway or water body into which the CWS 

discharges. The effluent limits will be established through 

the NPDES permitting process by the state in which the 

CWS is constructed and by EPA. 

CDPHE has identified stream standards for Clear Creek 

at the Burleigh Tunnel discharge. Table 2 provides these 

standards for both low- and high-flow conditions. The 

zinc standard for both low- and high-flow conditions is 200 

μg/L in the receiving stream (Clear Creek). In order to 

met this standard, the discharge from Burleigh Tunnel 

must contain less than 13,650 μg/L zinc under low-flow 

conditions and 65,700 μg/L under high-flow conditions. 

2.9.4 Occupational Safety and Health Act 

CERCLA remedial actions and RCRA corrective actions 

must be conducted in accordance with OSHA requirements 

detailed in 29 CFR Parts 1900 through 1926, especially 

Part 1910.120, which provides for health and safety of 

workers at hazardous waste sites. On-site construction at 

Superfund or RCRA corrective action sites must be 

conducted in accordance with 29 CFR Part 1926, which 

provides safety and health regulations for construction 

sites. State OSHA requirements, which may be 

significantly stricter than federal standards, must also be 

met. 

Construction and maintenance personnel and sampling 

teams for the Burleigh Tunnel CWS demonstration all 

met the OSHA requirements for hazardous waste sites. 

For most sites, the minimum personal protective equipment 

(PPE) required would include gloves, hard hats (during 

construction), steel toed boots, and eye protection. 

Additional PPE may be required during summer or winter 

months to protect against extreme temperatures. 

2.10 Limitations of the Technology 

Land required for constructed wetland systems is typically 

extensive compared to conventional treatment systems. 

Thus, in areas with high land values, a constructed 

wetland treatment system may not be appropriate. Land 

availability relatively close to the source of contaminated 

water is preferred to avoid extended transport. 

The climate at potential constructed wetland sites can also 

be a limiting factor. Extended periods of severe cold, 

extreme heat, arid conditions, and frequent severe storms 

or flooding can result in performance problems. 

Contaminant levels in treated and discharged water can 

vary in response to variations of influent volumes and 

chemistry. This may also be a limiting factor if there is no 

tolerance in contaminant level discharge requirements. 

19 
-- 

-- 

-- -- 

-- -- -- 

-- 

-- 

-- -- 

-- 

20
 

Table 2. Treatment Standards and Influent Concentrations of the CWS SITE Demonstration

Colorado Department of Public Health and Colorado Departm

Environment Chronic Water Quality Standards Environment Chronic 

Average Influent Concentration (Clear Creek) (Cle

Element (:g/L) Low Flow (:g/L) High 

Aluminum 20 

Arsenic 6 Cadmium 89 

Copper <10 

Iron 302 

Lead 16 Magnesium 46,000 

Manganese 2,360 

Nickel 47 Potassium 3,080 Silver 0.2 

Sodium 14,000 

Zinc 57,000 

Sulfate 383,000 

Fluoride 102 

Chloride 20,000 

Phosphorus (total) ND 

Orthophosphate 66 

Nitrate plus Nitrite (as 245 

N)Nitrite as N ND 

Nitrate as N 245 

Ammonia ND 

150 

0.84 

8.5 

1,000 

2.25 

1,000 

0.1 

0.039 0

200 

0.02 
Table 2 (continued). Treatment Standards and Influent Concentrations of the CWS SITE Demonstration 

21
 

Colorado Department of Public Health and Colorado Department of Public Healt 

Environment Chronic Water Quality Standards Environment Chronic Water Quality Sta 

Average Influent Concentration (Clear Creek) (Clear Creek) 

Element ( :g/L) Low Flow (:g/L) High Flow (:g/L) 

TSS 11,300 -- -­

TDS 680,000 -- -­

Alkalinity 104,000 -- --

(total as CaCO3) 

Alkalinity 104,000 -- --

(bicarbonate as CaCO3) 

Dissolved Oxygen 7.9 -- --

(mg/L) 

pH 7.11 pH units 6.5-8.5* 6.5-8.5* Conductivity 723 :S -- -­

Temperature 8.6 °C -- -­

Notes: 

* Secondary Maximum Contaminant Level 

-- No standards exist 
Section 3

The following sections discuss the treatment effectiveness 

of the CWS demonstration in Silver Plume, Colorado. 

The discussion includes a background section, a review of 

the demonstration, demonstration methodology, site 

demonstration results, and demonstration conclusions. 

3.1 Background 

The Burleigh Tunnel is located approximately 50 miles 

west of Denver in the Georgetown-Silver Plume mining 

district (Figure 1). The Georgetown-Silver Plume mining 

district occupies an area of about 25 square miles 

surrounding the towns of Silver Plume and Georgetown. 

In general, the period of significant silver production in the 

area commenced in 1872, reached a peak in 1894, and 

gradually declined after. Mining in the district increased 

briefly during World Wars I and II, when many old mines 

were reopened and considerable amounts of lead and zinc 

were mined from old stopes, dumps, and wastes left from 

the silver mining boom. 

The Burleigh Tunnel drains a group of mines on Sherman 

and Republican mountains. Many of these mines intercept 

shallow groundwater migrating through fractures in the 

rock or surface water collected by stopes. The intercepted 

waters are transported through the mines and are eventually 

discharged through the Burleigh Tunnel. The Burleigh 

Tunnel discharge contains elevated levels of zinc, typically 

between 45 and 65 mg/L. However, greater than normal 

precipitation during the spring of 1995 mobilized a large 

amount of zinc and increased zinc concentrations within 

the drainage to 109 mg/L. Burleigh Tunnel discharge 

rates are generally between 40 to 60 gpm and increase to 

100 to 140 gpm during spring runoff. The elevated levels 

of zinc and significant flow rates combine to make the 

Burleigh Tunnel a major source of zinc to Clear Creek. 

Because of the large amount of zinc being discharged to 

Clear Creek and the potential impact of the zinc on the 

Clear Creek fishery, the drainage from the Burleigh 

Tunnel was included in the Clear Creek/Central City 

Superfund site. 

The elevation of the Burleigh Tunnel is 9,152 feet, and the 

climate is typical of mountainous alpine regions in Colorado. 

Summers are short and cool and winters are long and cold. 

Strong eastward, down-valley winds are typical during the 

winter months. Winds are lighter during the summer 

months and occasionally blow westward, up the valley. 

Snow accumulation during the winter months in the 

immediate area of the tunnel is usually not significant due 

to the open, south-facing exposure of the hillside and high 

winds. Snow accumulation at higher elevations in more 

sheltered areas is significant, with some snow fields 

persisting until late summer. The average annual 

temperature is approximately 43.5 degrees Fahrenheit 

(°F), with a mean minimum of 31°F and a mean maximum 

of 55.9°F. The average annual precipitation is 15.14 

inches. 

3.2 Review of SITE Demonstration 

The SITE demonstration was divided into three phases: 

(1) CWS treatability study; (2) CWS technology 

demonstration; and (3) site demobilization. These activities 

are reviewed in the following sections, which also discuss 

variations from the work plan and the CWS performance 

during the technology demonstration phase. 

3.2.1 Treatability Study 

A treatability study was conducted at the Burleigh Tunnel 

between June 18, 1993, and August 12, 1993. The goal of 

the treatability study was to show that bacterial sulfate 

reduction could remove zinc from the low-sulfate mine 

drainage from the Burleigh Tunnel and to estimate levels 

of zinc reduction that could be expected by CWS treatment. 

The treatability study involved the construction, operation, 

and sampling of two bioreactors. Each bioreactor was 

22 

Treatment Effectiveness
filled with a mixture of composted manure (96 percent) 

and alfalfa hay (4 percent), the same substrate that was 

to be used in the CWS demonstration treatment cells. 

Both reactors used an upflow configuration, in which 

Burleigh Tunnel drainage entered the bioreactors from 

the bottom and was forced to flow up through the substrate. 

The small bioreactor was 4 feet tall and 22 inches in 

diameter and held approximately 60 gallons of compost 

and water. The large bioreactor was 8 feet tall and 22 

inches in diameter and held approximately 130 gallons of 

compost and water. The lower 6 inches of each bioreactor 

was filled with gravel to support inlet piping and minimize 

channeling. Peristaltic pumps were used to establish a 

flow rate of 20 to 30 milliliters per minute for the small 

bioreactor and 50 to 60 milliliters per minute for the large 

bioreactor. The flow rates for the bioreactors were set to 

provide an estimated hydraulic residence time of 50 to 

100 hours. 

The results of the treatability study indicated that after 

8 weeks of operation, both bioreactors achieved removal 

efficiencies of 99 percent for zinc and similar efficiencies 

for cadmium and manganese. Zinc was the major metal 

of concern for the Burleigh Tunnel drainage. Sorption of 

metals in the substrate is believed to be the dominant 

removal process during the first 1 to 2 weeks of bioreactor 

operation. After this brief period of sorption, biological 

sulfate reduction apparently became the primary metal 

removal process in the bioreactors. Results of sulfatereducing bacteria counts and sulfate and sulfide analyses 

indicated that a large population of sulfate-reducing 

microorganisms was active in the system. The results 

supported the theory that the bacteria reduce sulfate in the 

water to hydrogen sulfide ions, which react with dissolved 

metals to produce insoluble metal sulfides. The results 

indicated that the Burleigh Tunnel drainage contains a 

sufficient concentration of sulfate to promote metal removal 

by microbial sulfate reduction. Compost sample results 

from both bioreactors indicated that the compost 

accumulated metals and sulfide but did not become a 

reactive or hazardous waste after 8 weeks of operation. 

3.2.2 Technology Demonstration 

Site preparation requirements for the CWS demonstration 

were minimal because of previous mining and treatability 

study activities. Moreover, the area surrounding the 

Burleigh Tunnel adit is level and required only minor 

grading to install the two CWS treatment cells. Construction 

of the CWS treatment cells and all drainage conveyances 

was the responsibility of the developer (CDPHE). 

The demonstration evaluated two treatment cells that 

differed only in flow configuration, one upward and the 

other downward. The demonstration evaluated the ability 

of each cell to remove zinc and other metals from the 

Burleigh Tunnel mine drainage without pretreatment. 

Efforts were made to maintain constant flow rates; 

however, flow rates did vary. In addition, several events 

resulted in brief interruptions of flow to the cells. 

Approximately 12.7 million gallons of water from the 

Burleigh Tunnel were passively treated by the upflow 

constructed wetland cell and 11 million gallons by the 

downflow CWS over the 46-month demonstration. 

Figure 3 shows the flow rates measured for both wetland 

cell effluents during the demonstration. 

Throughout the demonstration, mine drainage influent and 

wetlands system effluent samples were collected for 

analysis of total metals, anions, total suspended solids 

(TSS), and total organic carbon (TOC). In addition, 

wetlands substrate samples were collected monthly for 

sulfate-reducing bacteria analysis and quarterly for analysis 

of total metals, acid-volatile sulfides (AVS), and toxicity 

characteristic leaching procedure (TCLP) metals. The 

substrate samples were analyzed to evaluate the 

effectiveness of the treatment system in sequestering 

zinc, to assess the tendency of the substrate to become a 

hazardous waste, and to estimate the role of sulfatereducing bacteria within the wetlands substrate. 

3.2.3 Operational and Sampling Problems

and Variations from the Work Plan 

The CWS experienced several operational problems during 

the demonstration. Some of these problems resulted in 

changes to the schedule and sampling events. Problems 

encountered and resolutions effected during the 

demonstration are described below. 

• The upflow cell froze in December 1993 and remained

frozen until the middle of February 1994. The cell 

froze because flow to the cells was interrupted when

the dike within the Burleigh Tunnel collapsed. The 

dike was quickly repaired; however, as a result of

the cold conditions and the lack of flow to the cells, 

the upflow cell froze to a depth of 18 inches. A 

livestock water heater and a steam cleaner were 

used to thaw the cell so that flow through the cell

could be maintained. The freezing of the upflow cell

delayed the start of the demonstration by 1 month.

In order to prevent the upflow cell from freezing

during the winter of 1995, straw bales were placed

on top of the cell to provide insulation from the cold. 

• The insulation provided by the straw bales maintained

the wetland water temperatures consistent with 

23 
influent values and the upflow cell effluent piping did

not freeze. 

• The 1995 spring runoff was exceptionally high, and

more flow was channeled to the CWS than the 

wetlands were designed to handle. More than 

20 gpm were flowing through the upflow cell for a 2-

week period in early June 1995. CDPHE responded

to the flooding by installing a 6-inch bypass pipe to

carry overflow from the influent weir around the

wetlands Once installed, the bypass allowed flow

rates to be returned to 7 gpm for each cell. However, 

CDPHE had not removed the straw bales insulating

the upflow cell before the spring runoff began, and

the straw bales became saturated. The weight of

the saturated straw compressed the substrate,

reducing the flow within the upflow cell to less than

1 gpm. The straw bales were removed from the 

upflow cell, and flow was restored to the cell within

a week. 

• In late November 1994, a large block of rock,

roughly 10 feet by 10 feet, fell from the hillside and

rolled onto a corner of the upflow CWS cell. The 

rock appeared to have depressed the effluent

accumulation network and created a high spot in the

piping at the collection point to the effluent weir.

The high point in the piping may have resulted in the

collection of precipitated metal sulfides in the piping,

causing a flow restriction. 

• During the summer and fall of 1994 and 1995, the

effluent flowrate from the downflow cell could not 

be maintained at 7 gpm. It was not clear if biological

surface growth, chemical precipitation in the cell, or

settling and compaction of fine particles in the

substrate was responsible for the decreased cell

permeability. 

• Several substrate sampling techniques were proposed

for the demonstration, including polyethylene dipper

and sediment core samplers. Both techniques

appeared to be equally effective; however, the dippers

were determined to be preferable. The dippers

were selected because they were inexpensive and

could be dedicated to each sampling cell, reducing

the number of equipment blank samples required

during the demonstration. 

3.2.4 Site Demobilization 

The demonstration-scale wetland was removed by 

CDPHE at the end of the demonstration. Wetland removal 

entailed: 

• Removal and disposal of the wetland substrate 

- Filling the wetland cells with site materials - Filling or removal of wetland weirs 

• The CWS demonstration substrate was not a 

hazardous material, and potential disposal options

included: 

- Disposal at a municipal landfill

- Disposal in landfill biobeds (compost piles)

- Mixing with site mining waste rock and soil to

provide needed organic matter 

- Reuse in an interim ponded wetland 

• The CWS Demonstration substrate was disposed of

in a nearby municipal landfill 

3.3 Demonstration Methodology 

The primary objectives of the CWS technology 

demonstration were to (1) measure the reduction of zinc 

in Burleigh Tunnel drainage resulting from the CWS 

treatment with respect to cell configuration and seasonal 

variation (temperature); (2) assess the toxicity of the 

Burleigh Tunnel drainage; (3) characterize the toxicity 

reduction resulting from treatment of the drainage by the 

CWS; and (4) estimate toxicity reductions in the stream 

(Clear Creek) receiving the Burleigh Tunnel drainage. In 

addition, secondary objectives of the demonstration 

included: 

• Estimating the metal removal capacity (lifetime) of

the substrate, including the effect of treatment cell

flow configuration. The results of influent and 

effluent metal analyses, CWS flow rate data, and

TCLP metal analysis were compared to substrate

metal accumulation estimates to evaluate the removal 

capacities of each CWS treatment cell. The TCLP 

metals analysis was used because the substrate

could become a hazardous waste before its metal 

removal capabilities were exhausted. Replacing the

substrate before it becomes a hazardous waste was 

determined to be the most cost-effective solution. 

• Estimating the extent to which sulfate-reduction

processes within the CWS are responsible for the

removal of zinc from the drainage. Substrate was 

analyzed for sulfate-reducing bacteria and acidvolatile sulfides to estimate the extent to which sulfatereduction processes are removing zinc from the

drainage. The approximate number of sulfatereducing bacteria was correlated to metal removal

efficiencies as part of the determination. In addition, 

the accumulation of AVS in the substrate was 

compared to metal loading in the treatment cells to 

determine trends. Furthermore, the AVS analyses

included an analysis of zinc to verify that the metal

sulfides accumulating in the CWS were zinc sulfides.

Previous investigations suggested that AVS analyses

were indicative of metal sulfide accumulation 

attributed to sulfate-reducing bacteria (Reynolds

1991). 

24 
• Evaluating the impact of the CWS effluent on Clear

Creek. Clear Creek samples were analyzed for total

metals, TSS, total dissolved solids (TDS), TOC,

nitrate, and phosphate. Results of the stream analyses

were compared to CWS effluent analyses to assess

the effect of CWS effluent on Clear Creek. Clear 

Creek samples were collected upstream and

downstream of the CWS outfall. 

• Estimating the capital and operating costs of the

CWS. 

Critical parameters are the data required to meet the 

primary objectives. The primary critical parameters were 

influent and effluent analyses for zinc (total), and toxicity 

testing with fathead minnows (Pimephalus promelas) and 

water fleas (Ceriodaphnia dubia). 

Noncritical parameters are data required to address 

secondary objectives of the demonstration. Secondary 

objectives provide useful information to potential technology 

users but are not critical to evaluate the technology. The 

noncritical parameters of the CWS demonstration included: 

• Total metals, nitrate and phosphate analysis of the

Burleigh Tunnel drainage and CWS effluents 

• Metal loading, metal accumulation, and TCLP metals

in CWS substrate samples 

• Sulfate-reducing bacteria counts and AVS

accumulation in CWS substrate samples 

• Clear Creek samples for total metals, TDS, TSS,

TOC, biochemical oxygen demand (BOD), and

aquatic toxicity 

• Construction, operation, maintenance, substrate

disposal, and miscellaneous costs 

3.3.1 Testing Approach 

In general, the testing approach of the demonstration 

incorporated the collection and analysis of wetland influent 

and effluent samples every 2 weeks for a period of 

20 months. Monthly sampling was conducted for the 

remainder of the nearly 4-year demonstration. The 

effluent zinc results for each sampling event were 

compared to influent data and a removal efficiency 

calculated. An initial 2-week interval was selected 

because it provided for 3 to 7 pore volumes of water to be 

passed through the CWS, assuming a hydraulic residence 

time of between 50 and 100 hours. In addition, the 2-week 

interval was chosen because several factors, such as 

precipitation or evaporation, could cause variation in the 

measured concentration of zinc in wetland effluent samples. 

By increasing the number of influent and effluent water 

samples, performance trends display better continuity, the 

effects of weather are reduced, and calculated removal 

efficiencies are expected to more closely reflect true 

values. Also, sampling intervals shorter than 2 weeks 

were not economically feasible considering the length of 

the demonstration. The initial 20-month schedule was the 

maximum time allowable for the demonstration. This time 

frame is allowed because the CWS is a biological 

technology and performance depended, in part, on primary 

substances and nutrients within the substrate. By allowing 

the system to operate for an extended period, results were 

expected to show a relationship (positive or negative) 

between declining nutrient concentrations in the substrate 

and CWS performance. 

The frequency of demonstration toxicity testing was 

limited to every 3 to 4 months due to budget considerations. 

Essentially, the sample collection and testing schedule 

was designed to evaluate toxicity reduction during periods 

of widely different zinc removal (different seasons) and 

critical periods for the receiving stream. 

3.3.2 Sampling, Analysis, and

Measurement Procedures 

Mine drainage samples were collected from the influent 

weir, and CWS effluent samples were collected from the 

effluent weirs. Clear Creek samples were collected 

above and below the CWS outfall. Influent and effluent 

samples were analyzed for total recoverable zinc and 

toxicity (critical analyses), other metals, anions, TDS, 

TSS, and TOC (effluent only). These samples were 

collected at the frequency discussed in the previous 

section. 

Two substrate sampling points were located in each cell. 

Initially, substrate samples were collected monthly for 

sulfate-reducing bacteria analysis and quarterly for total 

metals, AVS, and TCLP metals analyses for a period of 

20 months. Quarterly and semi-annual sampling was 

conducted for the remainder of the demonstration. 

Substrate samples were collected from two locations 

within each cell, at approximately 1 to 2 feet below the 

wetland surface. 

Mine drainage, wetlands effluent, and substrate were 

analyzed for critical and noncritical parameters using the 

methods listed in Table 3. 

Field analyses included measurement of pH and 

conductivity for all aqueous samples, Eh for wetlands 

effluent samples, and dissolved oxygen for mine drainage 

25 
Table 3. CWS Demonstration Summary of Standard Analytical Methods and Procedures 

Parameter Sample Type Method Number Method Title Source 

Metals Aqueous and 6010A, 6020, 7470 ICP, ICP/MS, or AA SW-8461 

Substrate 

Sulfate Aqueous 300.0 Ion chromatography MCAWW2 

Fluoride Aqueous 9056 Ion chromatography SW-846 

Nitrate/Nitrite Aqueous 353.2 and 354.1 Various MCAWW2 

Chloride Aqueous 300.0 Ion chromatography MCAWW2 

Total and Aqueous 365.3 Various MCAWW 

Orthophosphate 

pH Aqueous 9040 Electrometric MCAWW 

TSS Aqueous 160.2 Gravimetric MCAWW 

TDS Aqueous 160.1 Gravimetric MCAWW 

TOC Aqueous 9060 Various SW-846 

Ammonia Aqueous 350.1 Various MCAWW2 

Alkalinity Aqueous 310.1 Various MCAWW2 

Sulfide Aqueous 376.2 Various MCAWW2 

Aquatic Toxicity Aqueous EPA SOPs3 EPA5 

Acid Volatile Sulfide Substrate EPA Method Acid volatile sulfide EPA 1991 

(AVS) 

Sulfate reducing bacteria Substrate None Anaerobic deep tube CSM3 

count 

Toxicity leaching 

procedure 

Substrate 1311 ICP, ICP-MS or AA SW-846 

Reactive sulfide Substrate EPA4 Titration SW-846 

Orthophosphate Substrate 365.3 Various MCAWW 

Sulfate Substrate 300.0 Various MCAWW 

Physical parameters Substrate Various3 Various3 ASTM 

Residence time Aqueous ND ND ND 

pH Aqueous SOP3 12 Tetra Tech6 

Temperature Aqueous SOP3 11 Tetra Tech6 

Dissolved oxygen Aqueous SOP3 62 Tetra Tech6 

Conductivity Aqueous SOP3 99 Tetra Tech6 

Notes: 

1 Test Methods for Evaluating Solid Wastes, Volumes IA-IC: Laboratory Manual, Physical/Chemical Methods; and 

Volume II Field Manual. Physical/Chemical Methods, SW-846. 3d Edition. Office of Solid Waste and Emergency 

Response. U.S. Environmental Protection Agency (EPA). 1986. 

2 Methods for Chemical Analysis of Water and Wastes (MCAWW). EPA 600/4-79-020. Environmental Monitoring and 

Support Laboratory, Cincinnati, Ohio. EPA. 1983 and subsequent EPA - 600/4. 

3 The analytical methods selected for the analysis of critical and noncritical parameters, and the rationale used in their 

selection, are discussed in Section 4.2. 

4 Interim Guidance for Reactive Sulfide. Section 7.3.4.2, SW-846. 

5 Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms. 

EPA/600/4-90/027F. EPA 1993. 

6 These are field measurements made by Tetra Tech. 

26 
and Clear Creek samples. All field measurements were 

made in accordance with standard operating procedures. 

3.4 Site Demonstration Results 

This section presents the results of the CWS demonstration 

conducted from January 1994 to November 1997. Initially, 

aqueous chemistry data for the Burleigh Tunnel mine 

drainage are presented, followed by the demonstration 

results for the two CWS cells (Sections 3.4.1 through 

3.4.3). 

Section 3.4.4 presents data for the receiving stream, Clear 

Creek, and Sections 3.4.5 and 3.4.6 present toxicity 

results. Tables summarizing analytical results for 

the Burleigh Tunnel mine drainage are included in Appendix 

A. An evaluation of demonstration data quality parameters 

for critical analyses is contained in Section 4. 

The data discussed in this section were generally collected 

using demonstration sampling and analysis techniques. 

However, influent and effluent data for much of 1996 were 

collected and analyzed by the CDPHE laboratory 

(Analytica, in Broomfield, Colorado). In addition, data 

was not collected by Tetra Tech or CDPHE for 3 months 

(September through November) in 1996. Tetra Tech 

discontinued CWS sampling at the end of its initial SITE 

contract and the resumption of sampling was slowed by 

contractual delays. 

3.4.1 Burleigh Mine Drainage Chemistry 

The Burleigh Tunnel drains a network of interconnected 

mines on Republican Mountain and Sherman Mountain. 

Unlike many metal mine drainages, the Burleigh Tunnel 

effluent has near-neutral pH and carbonate alkalinity of 

approximately 100 mg/L. 

The mine drainage contains high levels of zinc that 

typically range from 45 to 65 mg/L. However, in May and 

June 1995, a great deal of spring snow and rain and a rapid 

thaw combined to increase the amount of runoff entering 

the mine network drained by the Burleigh Tunnel. At that 

time, flow from the tunnel increased from 45 gpm to more 

than 300 gpm, and zinc concentrations increased from 55 

mg/L (April 12, 1995) to 109 mg/L (August 8, 1995). 

Over the final 2 years of the demonstration, zinc 

concentrations in Burleigh Tunnel mine drainage were 

lower in the winter, dropped again in April or May when 

flow through the mine workings increased, and rapidly 

increased in summer, remaining high throughout the fall. 

During this period, Burleigh Tunnel mine drainage 

zinc concentrations generally remained between 45 and 

84 mg/L, with increases to more than 100 mg/L noted 

during the late summer and fall. Zinc concentrations in 

Burleigh Tunnel mine drainage between September and 

November 1996 are assumed to be similar to zinc 

concentrations measured during the same period in 1995. 

Figure 4 shows zinc concentrations for the Burleigh 

Tunnel mine drainage measured during the demonstration. 

In addition to zinc, cadmium, lead, nickel, and manganese 

are also demonstration metals of interest. Cadmium, lead, 

and nickel readily form sulfides and are expected to be 

removed by the CWS. Manganese does not form a stable 

sulfide but was shown to be removed in a shortterm treatability study conducted prior to the demonstration 

(PRC 1993). Cadmium, lead, and nickel levels were 

generally less than 0.1 mg/L in the Burleigh Tunnel mine 

drainage. After the high flow event in 1995, cadmium 

levels increased to concentrations ranging from 0.11 to 

0.26 mg/L. Lead and nickel levels were generally much 

lower than cadmium and did not increase to the same 

extent after the high flow event. 

Anion concentrations also increased during the 

demonstration. Sulfate concentrations in the Burleigh 

Tunnel drainage ranged from 279 to 652 mg/L and also 

increased after the high flow event. Carbonate (total 

alkalinity) concentrations were measured over a relatively 

narrow range of 82.4 to 125 mg/L. The highest carbonate 

concentrations were measured during a 1-month period 

in June and July 1995, corresponding to the period of 

highest flow from the Burleigh Tunnel. The simultaneous 

increases in zinc, sulfate, carbonate, and calcium without 

an increase in pH suggest these mine drainage constituents 

originate from mineral dissolution. Calcite (CaCO3) is 

commonly found in hydrothermal vein deposits in 

association with lead-silver-zinc formations (Correns 1969) 

and is also reported in the Silver Plume mining district. 

The high concentration of both zinc and carbonate at near 

neutral pH suggests the Burleigh Tunnel mine drainage is 

a combination of waters from multiple sources. 

3.4.2 Downflow CWS 

The downflow cell was operated for approximately 

21⁄2 years during the demonstration. Over this period, the 

system removed 60 to 95 percent of the zinc contamination 

from the Burleigh Tunnel mine drainage. 

Figure 4 shows zinc concentrations in the Burleigh Tunnel 

mine drainage (influent), and the effluents of both CWS 

27 
28

Figure 4. CWS zinc concentrations by month.
cells. During the first year of operation, influent zinc 

concentrations ranged from 45 to 63 mg/L (average of 

57.1 mg/L) and the amount of zinc removed by the 

downflow cell ranged from 35 to 54 mg/L (average of 

44.2 mg/L). Zinc removal efficiency during the first year 

averaged 77.4 percent. During the second year, zinc 

levels in mine drainage ranged from 53 to 109 mg/L 

(average of 83 mg/L) and downflow zinc removal ranged 

from 41 to 78 mg/L (average of 58 mg/L). Zinc removal 

efficiency during the second year averaged 70 percent. 

Over the final 6 months this cell operated, influent zinc 

levels ranged from 46 to 84 mg/L, while downflow CWS 

zinc removal ranged from 31 to 78 mg/L. In general, 

greatest zinc removal corresponded to times with the 

highest influent zinc concentrations, and the lowest zinc 

removal was observed during periods of lesser zinc in the 

mine drainage suggesting metal removal was effected by 

a physical process. 

Although present only in low levels in the influent water, 

cadmium, lead, and nickel were removed to a great extent 

by the downflow CWS treatment. Influent cadmium 

concentrations ranged from 0.071 to 0.10 mg/L, while 

effluent levels ranged from 0.0007 to 0.003 mg/L during 

the first year. During the second year, cadmium 

concentrations increased in the influent, ranging from 

0.057 to 0.26 mg/L, and downflow effluent levels ranged 

from 0.0001 to 0.007 mg/L with few detections. Figure 5 

shows cadmium concentrations for the influent and both 

effluents during the first 2 years of the demonstration 

Substantial cadmium removal continued over the final 

6 months by the downflow cell, with the exception of the 

April 1996 sample. 

Samples were not regularly analyzed for lead or nickel 

during the demonstration. Figure 6 shows lead 

concentrations for the influent and both effluents during 

the first 2 years of the demonstration. During the first 

year, influent lead concentrations ranged from 0.013 to 

0.020 mg/L, while downflow effluent concentrations 

ranged from 0.00065 to 0.0054 mg/L. Throughout the 

remainder of 1995, influent levels of lead increased 

slightly while effluent levels remained very low with few 

detections. 

Nickel was also removed by the downflow cell; however, 

the extent of removal declined when influent nickel 

concentrations increased after the high flow event. 

Nickel levels in the influent ranged from 0.033 to 0.68 mg/ 

L, and downflow effluent ranged from 0.0073 to 0.020 

mg/L in the first year. Throughout the remainder of 1995, 

influent nickel levels ranged from 0.045 to 0.093 mg/L, 

and downflow effluent levels ranged from 0.014 to 

0.040 mg/L. 

Manganese concentrations in the mine drainage were 

initially between 1 to 2 mg/L. Manganese removal by the 

downflow CWS was low during the demonstration. Figure 

7 shows manganese concentrations for the influent and 

both effluents. 

The extended residence time of the influent within the 

downflow cell substrate caused by low flow rates may be 

one reason the downflow CWS was effective in removing 

metals from the mine drainage. Both wetland cells were 

designed to treat 7 gpm; however, the permeability of the 

downflow cell declined during the first year of operation, 

and flow through the cell dropped to 4 gpm particularly 

during the summer months. Although attempts were 

made to increase its permeability by fluffing the substrate 

with compressed air, these procedures resulted in only 

temporary improvements. Flow through the downflow 

cell improved during winter months when the substrate 

froze and contracted from the liner allowing the influent to 

flow down the sides of the interior cell. Flow through the 

downflow cell averaged 6.5 gpm during the first year; 5.8 

gpm in the second year; and 6 gpm over the final 6 months 

of operation. 

Analytical results for the downflow substrate (Table 4) 

showed a substantial increase in zinc levels over the 

period of the demonstration. Substrate zinc levels ranged 

from a low of 59.7 milligrams per kilogram (mg/kg) to a 

high of 5,630 mg/kg. Substrate samples were generally 

collected from between 1 to 2 feet below the surface of 

the CWS. Downflow substrate samples contained little 

visible evidence of sulfate reduction and low concentrations 

of AVS. Sulfate-reducing bacteria counts showed much 

variability (Figure 8). 

After the first 6 months of operation, the downflow cell 

was removing more zinc from the mine drainage compared 

with the upflow cell. However, the reason for the greater 

removal was likely the higher residence time of the mine 

drainage within the downflow wetland. The increasing 

residence time was a function of mine drainage flow 

through the cell, that was generally lower in the summer 

compared to winter. A reduction of flow from 7 to 5 gpm 

increases residence time by 19 hours nearly a 40 percent 

increase. The loss of permeability is believed to be related 

to the loss of permeability in the downflow cell resulting 

from biological surface growth, chemical precipitation of 

29 
30

Figure 5. CWS cadmium concentrations by month.
Figure 6. CWS lead concentrations by month. 

31
32

Figure 7. CWS manganese removed by month.
Figure 8. Sulfate-reducing bacteria, downflow CWS substrate. 

33
Table 4. Average Downflow CWS Substrate Results 

SulfateAcid Volatile Reducing OrthoCadmium Lead Nickel Zinc Sulfides Bacteria phosphate 

(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (count) (mg/kg) 

0-6 months 2.7 18 3.1 1,100 180 8.5 x 104 34 

6-12 months 8.0 31 6.1 3,400 120 1.1 x 105 12 

12-18 months 23 74 7.0 5,200 460 3.3 x 105 2.6 

Notes: 

mg/kg Milligram per kilogram 

Average Arithmetic Mean 

Substrate samples collected from 1-2 feet below wetland surface 

zinc compounds, microbial breakdown of the substrate to 

finer particulates, and the settling of these particles into 

substrate pore spaces. The increase of flow during winter 

is believed to result from freezing of the wetland substrate 

at the edge of the cell causing the substrate to contract 

from the liner. The contraction allowed ponded water at 

the surface of the wetland to flow between the frozen 

substrate and liner to the base of the cell forming a 

preferential pathway. 

Loading is the amount of metals retained by the wetland 

over time. It is a function of the flowrate through the 

wetland, the concentration of metals in the mine drainage, 

and the removal efficiency of the treatment. For this 

discussion, monthly loading of each wetland was calculated 

from measured flow rates and simultaneously collected 

samples of the mine drainage and the wetland effluent. 

Figure 9 shows the monthly zinc loading to the downflow 

CWS over the demonstration. The graph indicates that 

loading was initially high (maximum of 60 kg/month) but 

dropped as the downflow cell flow rate declined in the Fall 

of 1994. In winter, loading also increased as flow 

improved. The greatest loading to the downflow CWS 

occurred during the high flow event in the late spring and 

early summer of 1995. After the high flow event, loading 

in this cell declined dramatically and eventually dropped to 

less than 5 kg/month in May 1996. 

The primary metal removal mechanism active in this cell 

did not appear to be sulfate reduction. Substrate analyses 

indicate a significant portion of the zinc removal in this 

CWS occurred in the upper 1 to 2 feet of substrate, where 

few AVS or sulfate-reducing bacteria were found. Pockets 

of sulfide-rich substrate were observed in this CWS cell 

at depths of 3 to 4 feet below the wetland surface, 

suggesting some sulfate reduction contributes to metal 

removal in this wetland. Aqueous geochemical modeling 

of the mine drainage suggests gypsum is oversaturated; 

however, visual observations of Burleigh Tunnel mine 

drainage precipitate and historical mine reports suggest 

the material is a zinc carbonate, probably smithsonite or 

hydrozincite. 

The following can be concluded from the evaluation of the 

downflow CWS: 

• As tested, the downflow CWS did not retain sufficient 

permeability to be considered a reasonable longterm treatment option. 

• Chemical precipitation (suspected to be mineral

carbonate accumulations) may have been the primary

metal removal process in this CWS treating Burleigh

Tunnel mine drainage. 

• A 2-foot substrate depth should be adequate, as

most metal removal occurred at between 1 to 2 feet 

below the wetland surface. A thinner substrate 

should decrease the flow resistence of the downflow 

CWS and increase the effectiveness of the system. 

• A 2-foot downflow CWS may be a good pretreatment

for an upflow CWS treating the Burleigh Tunnel

mine drainage allowing some physical precipitation

of the zinc. 

The concentration of orthophosphate in the substrate also 

decreased after the high flow event in 1995. The high 

orthophosphate concentration, measured at the beginning 

of the demonstration, was 114 mg/kg; the low, 1 to 2 mg/ 

kg, was measured in August 1995. 

34 
Figure 9. Monthly zinc loading, downflow CWS. 

35
3.4.3 Upflow CWS 

The upflow cell was demonstrated for nearly 4 years and, 

during this period, removed zinc and other metals initially 

by adsorption, later by sulfate reduction, and eventually by 

chemical precipitation (presumed). The adsorption period; 

appeared to last roughly 4 to 5 months as indicated by 

manganese removal. After the adsorption phase, sulfate 

reduction appeared to be the primary metal removal 

process; however, oxidation/reduction (ORP) 

measurements suggested the activity of the sulfatereducing bacteria appeared to drop in late fall and through 

the winter of 1994. Counts of sulfate-reducing bacteria 

declined coincidentally with the decline in ORP. The drop 

may have been caused by lower winter temperatures, or 

an increase in flow through the cell that occurred in 

September through October 1994, or may result from the 

use of all the most easily metabolized materials in the 

compost substrate by the bacteria. During this period, the 

concentration of zinc in the upflow effluent increased 

from 3.2 mg/L (October 12, 1994) to 18 mg/L (March 15, 

1995). 

By May 1995, zinc levels were approaching levels that are 

inhibitory to sulfate-reducing bacteria at the observed 

area loading of 250 square feet per gallon. During May 

and June of that year, the high flow event exposed the 

wetland sulfate-reducing bacteria to elevated levels of 

zinc, and the high influent flow probably created aerobic 

conditions within the cell. The periodic high zinc 

concentrations observed in influent waters during the 

summer and fall of 1996 and 1997 likely prevented the 

sulfate-reducing bacteria from reestablishing activity to 

previous levels. The flow was halted to the upflow cell in 

the summer of 1997 for approximately one month for 

repairs. At that time, much of the water was removed 

from the cell, allowing wetland sulfate-reducing bacteria 

an opportunity to become reestablished. 

However, there was no indication that the bacteria became 

re-established during the final 4 to 5 months of the 

demonstration. One of the repairs involved plugging a 

short section of the influent piping in the upflow cell. 

Visible observation of this influent pipe noted a black 

coating on the inside of approximately 1/16 inch and 

accumulations of black precipitate nearly filling the holes 

in the perforated pipe. Overlying the black material in the 

piping was a layer of cream colored to yellow material up 

to 1/8 of an inch thick. 

Analytical results for influent and effluent samples from 

the upflow system showed that zinc was nearly completely 

removed by this system during the first 8 months of the 

demonstration (Figure 4). After this period, zinc 

concentrations in the upflow effluent gradually increased 

from 1.4 mg/L (September 19, 1994) to 18.5 mg/L in the 

spring of 1995 corresponding to zinc removal efficiencies 

of 97.6 and 66.8, respectively. In May and June 1995, high 

flow from the Burleigh Tunnel increased flow through the 

upflow cell to 20 gpm and zinc concentrations nearly 

doubled. Over the next 6 months, as flow decreased from 

the tunnel, influent zinc concentrations rose to a high of 

109 mg/L. From May to November 1995, effluent zinc 

levels increased from 26.7 to 73.6 mg/L. The amount of 

zinc removed by the upflow cell averaged 41 mg/L (49.3 

percent) during the second year. 

During the third year of operation, zinc levels in the 

influent ranged from 56 to 84 mg/L; however, data were 

not collected between September and November 1996. 

Zinc concentrations in the upflow effluent over the third 

year ranged from 30 to 49 mg/L with an average removal 

of 30 mg/L (39.6 percent). In the final year of operation, 

zinc influent concentrations ranged from 42 to 104 mg/L 

and effluent levels ranged from 15 to 60 mg/L with an 

average removal efficiency of 65.1 percent. Effluent 

levels were greater in the May 28, 1997 sample (60 mg/ 

L) compared to the influent sample (56 mg/L). Over the 

final 6 months, the upflow cell removed greater amounts 

of zinc as flow through the cell decreased. Flow through 

the upflow cell at this time ranged from 2 to 5 gpm. 

Cadmium removal by the upflow cell followed a pattern 

similar to zinc removal (Figure 5). Initially, cadmium was 

removed to nondetect levels; however, cadmium 

concentrations increased two and a half times after the 

high flow event. After this period, cadmium removal 

remained high for 4 months but declined in the latter part 

of 1995 and remained low through 1996 and 1997. 

Lead (Figure 6) and nickel were also removed to lower 

concentrations by the upflow CWS. Influent lead and 

nickel concentrations were approximately 0.015 mg/L 

and 0.043 mg/L, respectively. During the first year, lead 

was removed to nondetect levels and nickel effluent 

concentrations ranged from 0.0005 to 0.019 mg/L. Unlike 

zinc and cadmium, lead and nickel concentrations did not 

increase significantly after the high flow event; however, 

the removal of both decreased somewhat until flow values 

through the cell declined in the final months of the 

demonstration. 

Manganese was initially present in the mine drainage at 

concentrations ranging from 1 to 3 mg/L. Manganese 

36 
was removed by the upflow cell for the first 4 months of 

operation but was not removed throughout the remainder 

of the demonstration. 

Analytical results for the upflow substrate showed an 

increase in zinc levels over the period of the demonstration. 

Table 5 summarizes mean annual results for selected 

analysis from upflow cell substrate samples collected 

during the demonstration. Zinc levels ranged from a low 

of 40 mg/kg to a high of 4,800 mg/kg. The zinc content is 

expected to be higher in the removal zone of the upflow 

cell (deeper in the substrate of the cell). In general, upflow 

substrate samples were collected approximately 2 feet 

below the wetland surface, above the removal zone. 

Counts of sulfate-reducing bacteria in the upflow cell 

were generally very high between April 1994, through 

July 1995. However, counts were 1 to 2 orders of 

magnitude lower in upflow cell samples collected in 

April 1996 through September 1997. The final substrate 

sample analyzed for sulfate-reducing bacteria 

contained approximately 250,000 CFU/gram substrate. 

Figure 10 shows the results of sulfate-reducing bacteria 

counts conducted on upflow cell substrate samples 

collected during the demonstration. 

The change from strongly reducing to slightly reducing 

conditions in the fall of 1994 may have made previously 

removed metal sulfides less stable within the wetland 

substrate. Substrate observations in the summer of 1997 

indicated there were fewer sulfides present compared to 

substrate samples collected in 1994 and 1995. If half of 

the zinc removed in the first year of operation were 

released over the subsequent 2 years, the resulting zinc 

Table 5. Average Upflow CWS Substrate Results 

Cadmium Lead Nickel 

(mg/kg) (mg/kg) (mg/kg) 

increase in the effluent would have been 33 mg/L. The 

higher zinc concentration measured in the May 28, 1997 

effluent sample compared to the corresponding influent 

sample suggests some previously removed zinc was 

released. 

Between March and December 1994, metals loading to 

the upflow CWS ranged from 53 to 97 kg/month but 

dropped to 26 kg/month in February 1995. This drop in 

loading corresponded with the increase of zinc in the 

effluent, an increase in ORP, and a decrease in flow rate 

through the cell. Flow through the cell increased in March 

and April 1995, leading to higher loading. The maximum 

loading to the upflow CWS (107 kg/month) occurred in 

May 1995 during the high flow event. Throughout the 

remainder of the demonstration, loading to this cell declined 

as the zinc removal efficiency decreased to 40 to 50 

percent; eventually, flow through the cell ended in 1997. 

Figure 11 shows zinc loading to the upflow CWS over the 

demonstration. 

The effect of the high flow event on the performance of 

the upflow CWS reveals the major shortcoming of passive 

systems, the inability to adapt to rapidly changing conditions. 

In this demonstration, the upflow CWS could not adjust to 

the increased influx of zinc or the change in environmental 

conditions. 

As several constructed wetlands have successfully treated 

mine drainage with much higher concentrations of zinc, it 

may be concluded that the bacteria are somehow able to 

protect themselves from the high metals concentration. If 

this mechanism is sulfate reduction, the rate of sulfate 

Acid Volatile Sulfate- OrthoZinc Sulfides Reducing phosphate 

(mg/kg) (mg/kg) Bacteria (count) (mg/kg) 

Year 1 0.17 9.9 1.9 40 210 7.2 x 106 55 

Year 2 0.18 13 2.0 71 460 3.2 x 106 54 

Year 3 5.0 40.0 4.1 1,500 1,300 2.2 x 105 6.3 

Year 4 9.6 NR 6.2 4,800 1,000 6.2 x 104 6.9 

Notes: 

mg/kg Milligram per kilogram 

NR Not Reported 

Average /Arithmetic Mean 

Substrate samples collected from 1-2 feet below wetland surface 

37 
38

Figure 10. Sulfate-reducing bacteria, upflow CWS substrate.
Figure 11. Monthly zinc loading, upflow CWS. 

39
reduction must be great enough to reduce zinc 

concentrations in the substrate to below inhibitory levels. 

This hypothesis suggests that the effectiveness of an 

anaerobic compost CWS is a function of the rate of sulfate 

reduction, residence time of the mine drainage in the 

wetland substrate, and the concentration of zinc (or other 

inhibitory metals) in the mine drainage. Low temperature 

is also a factor that will affect the activity of sulfatereducing bacteria in the wetland. 

The following can be concluded from the evaluation of the 

upflow cell: 

• The upflow CWS is effective in removing many

metal contaminants from mine drainage; however,

the CWS may have difficulty recovering from rapidly

increasing metals loading conditions. Reinnoculation 

and incubation of sulfate-reducing bacteria may

improve recovery of these systems. 

• Control of mine drainage flow to the constructed

wetland is critical to ensure that residence time and 

operational conditions are maintained. 

• The operational lifetime of an upflow CWS (with a

compost substrate depth of 4 feet) is roughly 4 to 

5 years. 

• The upflow cell had superior hydraulic performance

throughout most of the demonstration. 

• Winter freezing can be prevented by covering the

wetland surface with hay or blankets used in curing 

concrete. 

• Piping cleanouts should allow all piping networks to

be easily cleaned. 

3.4.4 Clear Creek 

The untreated Burleigh Tunnel mine drainage and the 

effluents of both CWS cells discharge to Clear Creek. To 

assess the impact of treatment on the receiving stream, 

upstream and downstream samples collected from Clear 

Creek were also analyzed for total metals and aquatic 

toxicity. The metals results indicated that although the 

wetlands may be removing metals from the mine drainage, 

the demonstration-scale CWS treated only a small portion 

of the total discharge from the Burleigh Tunnel, not 

enough to show a measurable decrease in the metals 

content of the stream. The demonstration-scale CWS 

treated approximately 30 percent of the total flow from 

the Burleigh Tunnel, and during high flow treated only 

about 5 percent of the flow. A full-scale system could 

show a more significant decrease in the metals content of 

Clear Creek downstream of the system. 

The stream results for upstream versus downstream 

samples are presented in Tables 6 and 7. The results show 

that Burleigh Tunnel mine drainage is a significant source 

of zinc to Clear Creek. However, CDPHE reports there 

are also additional nonpoint sources of zinc-contaminated 

water received by the creek. 

3.4.5 Toxicity Testing Results 

Constructed wetland treatment is a complex 

biogeochemical process involving adsorption, chemical 

precipitation, and microbial interactions with contaminants. 

The primary metal removal mechanisms in the CWS are 

chemical precipitation and microbial sulfate reduction; 

however, treatment may also complex metal contaminants, 

making them unavailable to receptor organisms. Thus, 

aquatic toxicity analyses were conducted by the EPA 

National Exposure Research Laboratory - Aquatic Toxicity 

during the demonstration to evaluate the reduction in 

toxicity resulting from CWS treatment. Two test organisms 

were used in the toxicity testing: water fleas (Ceriodaphnia 

dubia) and fathead minnows (Pimephales promelas). A 

total of eight rounds of aquatic toxicity testing were 

conducted during the demonstration. Initially, toxicity 

samples were collected and analyzed every 3 to 4 months 

until late 1995, when demonstration activities were 

temporarily suspended. When demonstration monitoring 

resumed, toxicity testing was conducted every 4 to 

6 months. In 1997, a microbial toxicity test was conducted 

on wetland sulfate-reducing bacteria with Burleigh Tunnel 

mine drainage. The results of the microbial toxicity test 

are presented in Section 3.4.6. 

Aquatic toxicity testing results correlated well with 

increasing zinc concentrations observed in the effluents of 

the treatment cells during the first 2 years of the 

demonstration. Results of testing conducted during the 

first 8 months of the demonstration indicate the effluents 

from both cells were not toxic to either the C. dubia or the 

P. promelas. The Burleigh Tunnel mine drainage was 

toxic to both test organisms at low concentration (dilution) 

throughout the demonstration. Table 8 provides influent 

and effluent concentrations resulting in the death of 

50 percent of the test organisms (LC50) in each round of 

testing. As zinc concentrations increased in the effluents 

of both cells through 1995, so did the toxicity to the test 

organisms. 

The first test conducted that year (February 1995) indicated 

that effluent from the upflow cell had become toxic to 

C. dubia at a concentration of 8.4 percent. The high 

runoff event that occurred in the spring of 1995 and 

40 
--

Table 6. Clear Creek Upstream 

Cadmium Lead Nickel Zinc Conductivity Temperature 

(mg/L) (mg/L) (mg/L) (mg/L) pH (:S) (°C) 

Average 0.0022 0.0034 0.0047 0.126 7.8 155.7 5.4 

Maximum 0.0094 0.013 0.015 0.56 8.1 167.5 9.7 

Minimum 0.0 0.0 0.0 0.11 7.6 144.0 0.9 

Notes: 

°C Degrees Celsius 

mg/L Milligrams per liter 

:S MicroSiemens 

ND Not Detected 

pH Standard units 

Average /Arithmetic Mean 

Table 7. Clear Creek Downstream 

Cadmium 

(mg/L) 

Lead 

(mg/L) 

Nickel 

(mg/L) 

Zinc 

(mg/L) pH 

Conductivity Temperature 

(:S) (°C) 

Average 0.00075 0.0013 0.0068 0.512 7.6 132.8 4.3 

Maximum 0.0017 0.0024 0.026 0.56 8.1 173.3 9.7 

Minimum ND ND ND 0.14 6.5 80.0 

Notes: 

°C Degrees Celsius 

mg/L Milligrams per liter 

:S MicroSiemens 

ND Not Detected 

pH Standard units 

Average /Arithmetic Mean 

associated increases in flow through the CWS cells and 

elevated zinc concentrations resulted in higher zinc levels 

in the CWS effluents. At that time, the effluent from both 

cells became toxic to the test organisms. The upflow cell 

effluent was toxic to C. dubia at a concentration of 

0.1 percent and to P. promelas at concentrations ranging 

from 1.2 to 2.3 percent. The downflow cell effluent was 

toxic to C. dubia at concentrations ranging from 0.31 to 

0.51 percent and to P. promelas at concentrations ranging 

from 2.6 to 30 percent. 

Over the final 2 years of the demonstration, the upflow cell 

effluent continued to be toxic to C. dubia at concentrations 

below 1 percent and to P. promelas at a concentration of 

14 percent. Toxicity samples were not collected from the 

downflow cell: operation of this cell was discontinued in 

September 1996. 

Demonstration toxicity testing results indicate that the 

ability of the wetlands to reduce toxicity to aquatic 

organisms gradually declined over the first 2 years. In 

addition, the high flow event in 1995 had a significant 

impact on zinc and toxicity removal by the upflow cell over 

the final 2 years of the demonstration. 

Water samples for toxicity testing were collected from 

Clear Creek above and below the CWS discharge three 

times during the demonstration. As mentioned, the 

constructed wetlands treated only 30 percent of the mine 

drainage; thus, the impact of treatment on the receiving 

stream was minor. One set of samples contained higher 

toxicity in the upstream sample while samples collected 

after June 1995 indicated that there was no acute toxicity 

in the upstream samples but that addition of the mine 

drainage to the stream resulted in an increase in toxicity. 

41 
Table 8. CWS Demonstration Toxicity (LC50) Results 

Indicator Species Collected Influent Effluent Effluent Upstream Downstream 

Fathead Minnows 

(Pimephalus 

promelas) 

08/24/94 

09/19/94 

1.1 

0.73 

No toxicity 

No toxicity 

NA2 

No toxicity 

No toxicity No toxicity 

02/22/95 1.6 No toxicity No toxicity 

06/12/95 1.0 2.3 2.6 No toxicity No toxicity 

09/05/95 0.62 1.2 30 

12/10/96 0.62 1.6 NA 

06/24/97 0.69 24 NA No toxicity No toxicity 

10/29/97 1.4 14 NA 

10/29/971 11 

Water Fleas 

(Ceriodaphnia dubia) 

08/24/94 

09/19/94 

0.46

0.31 

No toxicity 

No toxicity 

NA 

No toxicity 

No toxicity No toxicity 

Date Upflow Downflow Clear Creek Clear Creek 

02/22/951 1.0 8.4 No toxicity 

02/22/95 No toxicity 

06/12/95 0.10 0.43 0.51 No toxicity No toxicity 

12/10/96 0.09 0.22 NA 

06/24/97 0.43 0.41 NA No toxicity No toxicity 

09/05/95 0.10 <0.19 0.31 

10/29/97 0.15 0.13 NA 

10/29/971 0.19 NA 

Notes: 

1 Duplicate Sample 2 NA - Not analyzed 

3.4.6 Microbial Toxicity Testing 

Microbial toxicity testing was undertaken when repairs to 

the upflow cell indicated that there were few metal 

sulfides in the wetland substrate compared with 

observations conducted in previous years. The lack 

of metal sulfide deposits in the substrate suggested 

that the sulfate-reducing bacteria were not actively 

producing sulfide. Thus, Burleigh Tunnel mine drainage 

was tested at the Colorado School of Mines for toxicity to 

sulfate-reducing bacteria isolated from the upflow cell. 

The tests indicated that the mine drainage is inhibitory to 

sulfate-reducing bacteria at low concentrations (dilution) 

corresponding to a zinc concentration of 17.5 mg/L. 

In addition, zinc sulfate (ZnSO4·7 H2O) was used to 

show that the zinc was the toxic constituent (positive 

control) in the mine drainage. The zinc sulfate was also 

toxic to the sulfate-reducing bacteria at a similar zinc 

concentration (18.8 mg/L). The concentration of zinc in 

the Burleigh Tunnel mine drainage typically exceeds the 

inhibitory level measured in this study. A similar study 

conducted using Desulfovibrio desulfricans also found a 

zinc concentration of 13 mg/L resulted in inhibition to the 

bacteria. (Paulson and others 1997). 

Evidence that sulfate reduction was important to the 

removal of zinc in the upflow CWS include the large 

population of sulfate-reducing bacteria observed when 

zinc removal was also high (first year of demonstration), 

the accumulation of AVS, primarily zinc sulfide, in the 

substrate of this cell, and the decline of sulfate-reducing 

bacteria populations after the high flow event that 

corresponded with lower zinc removal by the upflow cell. 

42 
Visible observations of the upflow cell substrate observed 

blackening of the substrate during the first year of operation 

suggesting metal sulfides were accumulating, however, 

observations of wetland substrate conducted three years 

later, showed little blackening of the substrate. These 

results suggest sulfate-reduction was not as an important 

metal removal mechanism and was occurring to a much 

lesser extent during the latter portion of the demonstration. 

These observations also suggest that previously formed 

metal sulfides are not stable when environmental conditions 

within the wetland changes. 

3.5 Attainment of Demonstration 

Objectives 

This section discusses the results of the CWS demonstration 

in regard to the attainment of primary and secondary 

demonstration objectives. In addition, metal removal 

mechanisms, some of the causes for poor performance, 

and substrate lifetimes are discussed for each cell. 

The results of the demonstration were able to achieve 

many but not all of the primary objectives outlined in 

Section 3.3. The first primary objective was the 

measurement of wetland effectiveness with respect to 

cell flow configuration and seasonal variation. This 

primary objective was achieved in part. The demonstration 

zinc results indicate zinc removal is greater with an upflow 

configured wetland; however, the technology as tested is 

not capable of meeting low metal discharge requirements 

for extended periods. 

The better zinc removal and flow of the mine drainage 

through the upflow CWS compared to the downflow 

CWS indicate the upflow configuration is superior. 

Unfortunately, it was not possible during this demonstration 

to determine the effect of season variation on the 

performance of the upflow CWS. The downflow CWS 

actually performed better during the winter. The reason 

for the improved winter performance is discussed in 

Section 3.4.2. 

The second primary objective was to determine the 

toxicity of the Burleigh Tunnel mine drainage. This 

primary objective was achieved. The Burleigh Tunnel 

mine drainage is toxic to both the C. dubia and P. 

promelas. Measured LC50 values for the P. promelas 

(fathead minnows) ranged from 0.62 to 1.6 percent (mine 

drainage) and for the C. dubia (water fleas) ranged from 

0.10 to 1.0 percent. 

The third primary objective was the characterization of 

toxicity reduction resulting from CWS treatment. This 

primary objective was also achieved. The demonstration 

toxicity results indicate the ability of the wetlands to 

reduce toxicity to aquatic organisms declined over the first 

two years of operation. Further, the high flow event had 

a significant impact on toxicity removal in both wetland 

cells. 

The final primary objective was to estimate the toxicity 

reduction to the mine drainage receiving stream (Clear 

Creek). This primary objective was not achieved as none 

of the demonstration stream samples were toxic to either 

test organism. 

The most significant primary objective not achieved is the 

inability to determine the seasonal variability of the upflow 

CWS. During winter, constructed wetlands located in 

cold climates may be less effective as a result of lower 

microbial activity. This may require pretreatment of the 

mine drainage during winter, oversizing the CWS or 

retaining a portion of the flow until warmer conditions 

return. 

The first secondary objective of the demonstration was 

to estimate the lifetime of the substrate material. The 

lifetime of substrate material is estimated to be 4 to 5 

years. The estimate is based on the breakdown of the 

substrate material resulting in settling and compaction of 

the substrate that leads to flow restrictions. In addition, 

demonstration substrate data for nutrients indicate 

elements such as phosphate (orthophosphate) have been 

depleted in the substrate by this time. If low discharge 

limits must be met then demonstration results suggest the 

substrate lifetime is approximately one year (taking into 

account the demonstration starting time and freezing of 

the upflow cell during the first year). However, in this 

situation it would likely be more cost effective to pretreat 

the mine drainage or amend it with an electron donor such 

as ethanol to extend the lifetime of the substrate material. 

The second, noncritical or secondary objective was to 

estimate metal removal by sulfate reducing bacterial. 

This evaluation was expected to be qualitative as the 

bacteria counts and acid-volatile sulfide analyses are not 

highly precise and the metal removal may not be uniform 

throughout the treatment cells. As discussed in Section 

3.4.2, the downflow cell data did not indicate the primary 

metal removal mechanism to be sulfate reduction. Section 

3.4.3 discusses the upflow cell results for sulfate-reducing 

bacteria removal of metals. Data indicated an initial high 

43 
rate of removal with a longer term reduction in this 

mechanism of metals removal. 

The third noncritical, secondary objective was to evaluate 

the impact of the systems effluent on Clear Creek. These 

data are discussed in Section 3.4.4, and indicate that 

although the treatment was effective in removing metals 

from the Burleigh Tunnel drainage, the relatively small 

portion of the discharge being treated did not produce a 

measureable decrease in the metals content of Clear 

Creek. 

The fourth and final noncritical objective was to evaluate 

capital operating costs for the CWS. Section 5.0 of this 

report provides a detailed economic analysis and 

successfully provides data useful for estimating costs for 

application of this technology at other sites. 

3.6 Design Effectiveness 

The following sections discuss the effectiveness of the 

upflow and downflow CWS tested during the Burleigh 

Tunnel demonstration. The basic design of each wetland 

cell is discussed in Section 1.3.2 of this report. This 

discussion focuses on general design parameters and 

factors that affected each cell. 

The basic design of the CWS demonstration system 

consisted of a dam inside the Burleigh Tunnel, piping from 

the dam to the influent weir, the two wetland cells, an 

effluent weir, and a bypass pipe. The dam collected the 

mine drainage and provided adequate hydraulic head to 

drive the mine drainage through the upflow cell. The 

influent weir partitioned the mine drainage to the CWS 

cells and channeled the excess water to the bypass piping. 

From the influent weir, the mine drainage was channeled 

to a ball valve that separated flow to the CWS cells. Water 

collected from the cells was piped to the effluent weir and 

was discharged to Clear Creek. The purpose of the 

effluent weir was to regulate flow through the wetland 

cells. 

Construction materials associated with this design were 

generally inexpensive, readily available, and easily 

transported to remote areas. Installation techniques were 

also straightforward. 

The major drawbacks of this design observed during the 

demonstration centered on the flow control valves and 

the inability of the effluent weir to regulate flow through 

the cells. Because flow through the cells could not be 

controlled with the effluent weir, flow through the cells 

was regulated at the influent weir and control valve. 

Unfortunately, this design meant that any adjustment in 

flow to one cell affected flow to the other cell. Future 

systems should use easily controlled flow structures such 

as weirs to regulate flow to both cells independently. 

In addition, the capacity of the initial 4-inch bypass line 

was insufficient to accommodate the large water volume 

during spring runoff. Eventually, a 6-inch bypass line was 

installed. Piping connecting the influent control structure 

and the cells should be direct and accessible for routine 

cleanout. 

A drawback associated with the use of compost substrates 

is the high concentration of nitrate in the effluent water 

during startup. During this demonstration, no attempt was 

made to remove the nitrate from the water prior to 

discharge. In a similar wetland evaluation, startup effluents 

were applied to surface soils. Alternatively, the startup 

effluent could be stored on site in a pond or tank and fed 

back into the CWS. 

3.6.1 Downflow Cell 

The downflow cell consisted of 4 feet of a compost (95 to 

96 percent) and hay (4 to 5 percent) substrate. The mine 

drainage flowed from the top to a PVC piping collection 

network at the base of the cell. The influent and effluent 

distribution networks were staggered within the cell to 

minimize short-circuiting of the mine drainage in the 

substrate. 

The design of the downflow cell is discussed in 

Section 1.3.2; Figure 2 shows a cross section of the 

anaerobic CWS in an upflow configuration. The downflow 

configuration is only a reversal of the influent and effluent 

flows, not the construction of the cell. 

For the most part, the materials used in the construction of 

the cells–HDPE liner, geonets, and PVC piping were 

acceptable. However, the geofabric was found to fill with 

fine material and lose permeability over the 21⁄2-year 

demonstration. In addition, the cell piping networks did not 

include cleanouts. Cleanouts should be included in future 

CWS designs. Finally, the influent piping network did not 

evenly distribute the mine drainage in this cell. An 

additional row of perforated piping in this cell would more 

evenly distribute the mine drainage. 

The cell was designed to treat 7 gpm. However, during 

the demonstration, the downflow cell became less 

permeable. The permeability loss is believed to be related 

44 
to precipitation of metal oxides, hydroxides, and carbonates, 

settling of fine materials in the cell, and compaction of the 

substrate material. In winter months, flow through the 

downflow cell improved; presumably, the contraction of 

frozen substrate allowed water to flow between the liner 

and the substrate. However, this short circuiting did not 

substantially affect metal removal by the cell. 

In an attempt to restore flow through the downflow cell, 

air was injected into the substrate to fluff the material. 

Although this technique improved flow, the effect was 

typically short lived. The results of this demonstration 

indicate that substrates with high concentrations of compost 

will not retain permeability in a downflow configuration 

and are not recommended. However, some recent 

downflow wetlands have used substrate mixtures of 50 

percent limestone with sawdust and compost to improve 

hydraulic characteristics. 

3.6.2 Upflow Cell 

The design of the upflow CWS is identical to the downflow 

cell except that the mine drainage is channeled up though 

the compost substrate. Figure 2 shows a cross section of 

the demonstration anaerobic compost CWS. The design 

of the demonstration wetlands is discussed in Section 

1.3.2. 

In general, the upflow cell retained permeability throughout 

the demonstration. However, some hydraulic restriction 

developed during the later half of the demonstration 

resulting in a preferential flow pathway. In addition, gas 

buildup produced by fermenative bacteria within the 

upflow cell may have restricted flow to the effluent lines 

in the wetland during the last year of the demonstration. 

Gas was released from the cell by periodically puncturing 

the upper geofabric with a pitch folk. Replacing the 

geofabric with a fine mesh geonet could eliminate gas 

buildup. Also, the decline of sulfate-reducing bacteria and 

apparent increases in the population of fermentative 

bacteria likely exacerbated the problem. 

The upflow cell was prone to freezing during winter. 

During startup, the dike within the Burleigh Tunnel gave 

way, stopping flow to the upflow cell. Flow was restored 

by thawing the ice around the effluent line with a steam 

cleaner and water tank heater. The following winter, hay 

bales were placed over the substrate followed by insulated 

blankets (identical to insulated blankets used for curing 

concrete), and the system was operational throughout the 

winter. However, the straw bales became saturated with 

water and the combined weight compressed the substrate 

so that all flow ceased through the cell. Flow through 

the cell was restored once the hay bales were removed. 

During year three, the insulated blankets were used alone 

to insulate the cell and there were no interruptions in flow 

during this period. In the final year, the ponded water in 

the upflow cell was allowed to freeze and did so to a depth 

of approximately 6 inches. There were no interruptions in 

flow during that winter. 

Residence time is an important factor in anaerobic 

constructed wetlands that use sulfate-reducing bacteria. 

Decreasing residence times may overload the wetland, 

exposing the bacteria to inhibitory concentrations of zinc. 

Based on the size of the wetlands and substrate water 

volumes (percent moisture results of 50 percent) the 

calculated residence time for a flow rate of 7 gpm is 

48 hours, and 67 hours at a flow rate of 5 gpm. Verification 

of residence times was one of the more difficult 

measurements undertaken during the demonstration. Both 

a chloride tracer (treatability study) and an organic dye 

test (demonstration) were unsuccessful in measuring 

residence time. The chloride could not be readily measured 

as background levels of dissolved salts was somewhat 

high during the treatability study and the organic dye likely 

absorbed to the wetland substrate during this demonstration 

test. 

During the final year of the demonstration, flow through 

the upflow cell began to short circuit in an area adjacent 

to the southeastern bermed sidewall. An excavation was 

made into the wetland to the influent line feeding this 

section of the cell and the line was capped. Dewatering 

the excavation was somewhat difficult and would have 

been aided by a sump within the cell. Inspection of the 

influent line found precipitates coating the piping walls and 

in the piping perforations. The amount of material in the 

perforations and the pressure on the piping against the 

geofabric would have caused a notable restriction in flow. 

Replacing the geofabric with a fine mesh geonet should 

alleviate the problem. 

45 
Section 4
 

Data Quality Review
 

This section presents the summarized results of QA 

procedures established to ensure the validity of the zinc 

and acute toxicity data collected during the demonstration. 

Section 4.1 discusses zinc data quality, and Section 4.2 

discusses acute toxicity data quality. A comprehensive 

discussion for both zinc and acute toxicity, along with 

supporting summary tables, is presented in the Technical 

Evaluation Report. 

4.1 Zinc Data Quality Review 

This section discusses the results of the QA procedures 

established to ensure the validity of the zinc data collected 

during the demonstration. The QA procedures were 

established prior to the demonstration and were recorded 

in the quality assurance project plan (QAPP) as part of the 

demonstration plan. Both field and analytical QA 

procedures were specified to ensure sample integrity and 

the generation of data of known quality. 

4.1.1	 Quality Assurance Results for Field

Sampling Activities 

The procedures followed during field activities to maintain 

sample integrity and quality are discussed below. They 

include specifications for sample collection, labeling, 

containerization, preservation, holding times, and chain of 

custody. 

Sample Containerization, Preservation, and Holding

Times 

This section describes sample labeling, shipment, chainof-custody, and laboratory receipt procedures for zinc 

samples. Conformance with and documentation of these 

procedures provide a definitive record of sample integrity 

from origin to analysis. 

Each sample container was labeled with a unique sample 

identification number. The label identified the sampling 

location, date, time of collection, and analysis to be 

performed. All chain-of-custody forms included the 

project number, project name, sampler’s name, station 

number, date, time, sampling location, number of containers, 

and analytical parameters. Samples were hand-delivered 

to Quanterra Environmental Services in Arvada, Colorado. 

Chain-of-custody forms gathered during the demonstration 

were reviewed for content and completeness and appeared 

in good order. 

All samples analyzed for critical parameters arrived at the 

laboratory intact. Several of the coolers used for shipping 

the samples arrived with inside temperatures greater than 

4 degrees Celsius as specified in the QAPP. However, 

the results of associated QA samples suggest that the 

elevated temperature did not affect sample integrity. All 

samples were analyzed within their designated holding 

times (6 months); the majority were analyzed within 

1 month of sample collection. 

Equipment and Field Blanks 

Equipment blanks were collected during the demonstration 

to assess sample contamination resulting from sampling 

equipment. Throughout the demonstration, dedicated 

sampling equipment was used for sample collection to 

reduce sample cross contamination. As a result, few 

equipment blanks or field blanks were collected during the 

demonstration. The data quality objective (DQO) for 

equipment and field blanks was results below reporting 

limits for all analytes. 

Two equipment blanks (WEV090794EB and EB012197) 

were collected with a polyethelene dipper by pouring 

deionized water into the dipper and decanting the water 

into an appropriate sample container. The equipment 

blank collected in September 1994, contained an estimated 

zinc concentration of 0.019 mg/L, which is below the 

0.020 mg/L reporting limit. The equipment blank collected 

in January 1997, contained 0.052 mg/L zinc, above the 

0.020 mg/L reporting limit. 

46 
Field blanks were used to assess whether zinc 

contamination was introduced during the handling, 

presentation, or transport of aqueous samples. The field 

blank was prepared by adding deionized water into an 

appropriate sample container in place of a real sample. 

One field blank was collected during the demonstration 

(FB060194). Zinc was found in this field blank at a 

concentration of 0.034 mg/L, slightly above the reporting 

limit of 0.020 mg/L. 

The level of contamination in the equipment and field 

blanks qualifies data near the reporting limit for accuracy. 

The source of the contamination is unknown; however, 

the commercial distilled water is suspected. All of the 

CWS performance data contained zinc concentrations 

at least one order of magnitude greater than the 

reporting limit and in most cases two or three orders of 

magnitude above the reporting limit. Consequently, the 

demonstration zinc data are considered acceptable for 

their intended use. 

Method Blanks 

Method blanks verify that laboratory extraction and sample 

cleanup and concentration procedures used do not introduce 

contaminants that compromise the analytical results. 

Method blanks were prepared and analyzed with each 

batch of laboratory analysis. The method blank DQO was 

for results to be below reporting limits for all analytes of 

interest. 

Five out of the 40 batches analyzed during this 

demonstration contained reportable quantities of zinc in 

the method blanks. Values ranged from 0.020 mg/L to 

0.046 mg/L. All samples corresponding to these five 

analytical batches were qualified for blank contamination 

(B). All of the sample results were greater than five times 

the associated blank contamination; thus, no zinc results 

were qualified as nondetected due to blank contamination 

(UB). 

4.1.2	 Quality Assurance Results for

Sample Analysis 

Analytical QA includes methods and procedures used to 

ensure data reliability. This process involves establishing 

data quality objectives for the project data and developing 

data quality indicators (quanitative or qualitative measures 

of precision, accuracy, completeness, representativeness, 

and comparability) that can be used to determine whether 

the data meet the project’s QA objectives. 

The QA objective for the CWS demonstration data were 

established in the QAPP with specific performance goals 

for precision, accuracy, representativeness, completeness, 

and comparability. The following sections evaluate the 

demonstration data with respect to these performance 

goals. 

Precision and Accuracy 

Precision is a measure of the reproducibility of 

measurements under a given set of conditions. Accuracy 

is the degree of agreement between an analytical 

measurement and the true value. The overall precision for 

zinc concentrations was a function of both sampling and 

laboratory precision. Overall precision was evaluated 

using data from field duplicates, and laboratory precision 

was evaluated using data from laboratory duplicates. 

Relative percent difference (RPD) between duplicate 

samples was used to evaluate precision using the following 

formula: 

RPD = |(A - B)| X 100 

0.5 (A + B) 

where:	 A = first duplicate concentration 

B = second duplicate concentration or 

Fifteen field duplicate samples were collected during 

this demonstration, yielding RPDs ranging from 0 to 

3.7 percent. Laboratory duplicate control sampling were 

analyzed for 51 rounds of sampling activities. All laboratory 

RPDs were within the established DQO of 20 percent 

with the exception of one, of 28 percent. Overall, the 

precision objectives for zinc analyses were achieved. 

The accuracy of a measurement is affected by errors 

introduced through the sampling process and in handling, 

sample matrix, sample preservation, and analytical 

techniques. A program of sample spiking at the laboratory 

and analysis of standard reference materials (SRMs) was 

also used to evaluate laboratory accuracy. 

Accuracy for zinc measurements was estimated as percent 

recovery (%R) of the true analyte level from SRMs and 

by evaluation of matrix spike (MS) recoveries. The 

following formula was used to calculate MS percent 

recovery: 

% R = (S-C)/T X 100 

47 
where:	 S = measured spike concentration 

C = sample concentration 

T = true or actual concentration of the spike or 

MS spiking recoveries were all within the DQO limits with 

one exception. One MS sample analyzed (collected on 

July 27, 1994) yielded a recovery of 134 percent, slightly 

above the DQO. When the data were rechecked by the 

laboratory, the deviations were not found to bias the 

results sufficiently to affect data use. The laboratory 

concluded that the magnitude of the errors was too small 

relative to the zinc concentrations to have a significant 

effect on the zinc values. 

Reported results for the SRM indicate that the analytical 

method measured larger concentrations of zinc than 

reported in National Institutes of Standards and Testing 

(NIST) standard reference material 1643c. The higher 

recoveries were considered to be the result of matrix 

interferences and the low level of zinc in the SRM. The 

DQO for accuracy is 75 to 125 percent recovery. SRM 

recoveries were 123 and 149 percent. Quanterra was 

immediately notified of the problem, and the laboratory 

control samples were checked to confirm that all other 

analytical controls were within acceptable parameters. 

Tetra Tech determined that some demonstration results 

with very low levels of zinc may be positively biased. The 

zinc results affected are from the upflow cell effluent 

during the first 6 months of operation. 

Overall laboratory accuracy for the demonstration data 

was acceptable. 

Representativeness 

Representativeness expresses the degree to which sample 

data accurately and precisely represent the characteristics 

of a population, parameter variations at a sampling point, 

or an environmental condition they are intended to 

represent. For the CWS demonstration, the low RPDs 

associated with field duplicate results suggest the data 

collected are representative of the CWS system for the 

environmental and physical conditions at the Burleigh 

Tunnel site. 

Completeness 

Completeness is a measure of the amount of acceptable 

data obtained compared to the amount of data needed 

to achieve a particular level of confidence in the results. 

Acceptable data are obtained when (1) samples are 

collected and analyzed in accordance with the 

QC procedures outlined in the demonstration plan, and 

(2) criteria that affect data quality are not exceeded. 

CWS percent project completeness (%C) was calculated 

using the following equation: 

%C = (V/T) X 100 

where: %C = percent completeness 

V = number of measurements judged 

acceptable 

T = total number of measurements planned 

The QA objective for degree of completeness was 

90 percent for the critical parameter zinc. All data 

collected are considered usable for the intended purpose; 

therefore, the QA objective for completeness was 

achieved. 

Comparability 

The comparability parameter is designed to identify 

deviations in the data that may result from inconsistencies 

in field conditions, sampling methods, or laboratory analysis. 

During this demonstration, changes in sampling techniques 

and laboratory analysis were minimized to ensure 

comparability of results. However, the end of the first 

SITE contract and delays in restarting the new SITE 

contract required the use of data collected by CDPHE. 

The results of a laboratory intercalibration exercise with 

Quanterra, the CDPHE laboratory (Analytica), and a 

referee laboratory suggest that the data are comparable. 

4.2 Acute Toxicity Data Quality Review 

This section discusses the results of QA data collected to 

document the validity of the acute toxicity data. The QA 

procedures were established prior to the demonstration 

and recorded in the QAPP as part of the demonstration 

plan. Both field and analytical QA procedures were 

specified to ensure sample integrity and the generation of 

data of known quality. 

4.2.1 Analytical Quality Assurance 

Analytical QA is the process of ensuring and confirming 

data reliability. This process includes establishing 

DQOs for the project data and developing data quality 

indicators (quantitative or qualitative measures of precision, 

accuracy, completeness, representativeness, and 

comparability) that can be used to evaluate whether the 

data met the project’s QA objectives. The QA objectives 

for acute toxicity testing during the CWS demonstration 

48 
were established in the QAPP and are summarized in the 

following discussions. 

Water Chemistry Results for Environmental 

Samples and Reference Toxicant Tests 

To ensure that laboratory water quality conditions did not 

adversely affect the reference toxicant or environmental 

sample results, water quality parameters were documented 

throughout all test series. The water chemistry results 

indicate that the water quality conditions for testing were 

appropriate for the test organisms during all test dates and 

that no abnormal water conditions were documented that 

could influence the survivability results. 

Precision and Accuracy 

Precision and accuracy in toxicity tests are controlled and 

evaluated through documentation of reference toxicant 

responses of indicator species against inter- and intralaboratory historical records; and by carefully controlling 

and documenting the environmental conditions tested. 

The following discussion documents the laboratory testing 

conditions for growth, feeding, and maintenance of indicator 

species during the tests; and documents the results of 

indicator species survivability results against laboratory 

historical records for identical tests. 

Acute toxicity and metal concentration in the mine drainage 

were used to infer a response relationship between the 

most prevalent toxic component present (zinc) and indicator 

species survival. Preliminary chemical analysis had 

identified zinc in various forms as the most predominant 

metal contaminant. 

Zinc sulfate was used as a reference toxicant to simulate 

the population response of the indicator species to a 

soluble zinc compound present in the mine drainage 

matrix. Potassium chloride was used as a laboratory 

reference test for population viability and toxic response 

of the indicator species. 

Pimephales promelus and Ceriodaphnia dubia were used 

as the test organism populations in the 48-hour staticrenewal acute toxicity tests. Indicator species survival 

rates (LC50) at the 95 percent confidence level (EPA 

1993a) in a static series of potassium chloride and zinc 

sulfate concentration dilutions were calculated and 

compared with laboratory historical records. The 

comparison provided a control on the viability of the test 

species and the testing methodology. 

The quantitative precision and accuracy requirements for 

acute toxicity for Pimephales promelus and Ceriodaphnia 

dubia when exposed to zinc sulfate were established by 

toxicant equivalent concentration values generated from 

both external and internal laboratory records of earlier 

tests. The quantitative precision and accuracy objectives 

for acute toxicity for Pimephales promelus and 

Ceriodaphnia dubia when exposed to potassium chloride 

were established by monthly cumulative laboratory toxicant 

equivalent concentration values. 

All reference toxicant results fell within the prescribed 

ranges, indicating that the response of the indicator 

species response to test conditions was appropriate for 

evaluating the toxin present. Therefore, the quantitative 

results of acute toxicity to the environmental samples are 

comparable to other tests under identical conditions. 

Sample Duplicates 

The results of sample (field) duplicates is another indicator 

of overall precision. The sample duplicate was collected 

on February 27, 1995 from the treated effluent from the 

downflow cell (samples designated WED and WEDII). 

Generally, the analysis of duplicate acute toxicity values 

for sampling and analytical precision is a numerical 

comparison of the difference in reported acute toxicity 

values to the magnitude of the values themselves. 

However, sample WED for February 27, 1995 was not 

toxic enough to generate an LC50 value, which is the 

normal endpoint for acute toxicity analysis. Consequently, 

the analysis of test sampling and analytical precision 

presented is a subjective comparison of the sample and 

duplicate routine chemistry and intermediate toxicity 

results. 

The chemistry for duplicate samples WED and WEDII 

shows no significant difference, with less than 10 percent 

variation in all measured parameters. Those variables 

having the greatest difference – in pH, DO, and temperature 

– were consistently lower for WEDII than for WED. The 

values, however, do not strongly indicate a difference in 

water quality conditions. The initial and final chemistry for 

both species tests also show slight differences, but no 

consistent variability in an individual parameter. 

Qualitatively, the survival rates for C. dubia of the individual 

sample dilutions for duplicate samples WED and WEDII 

both show very slight toxicity, especially noting that both 

controls had survival rates of 20/20. Quantitatively, the 

100 percent WEDII sample yields a survival ratio 

49 
statistically different than the control when tested with 

Steel’s Many-One-Rank test at an = 0.05 (EPA 1993a). 

WED at 100 percent concentration did not exhibit sufficient 

mortality for the survival ratio to be statistically different 

than the control. 

The acute tests with P. promelas do not show any 

statistical difference from the control for WED or for 

WEDII; therefore, no toxicity for this species is evident. 

In general, C. dubia is more sensitive to environmental 

toxicants, so the absence of toxicity for P. promelas 

supports the presumption that WEDII is slightly toxic. 

Using the C. dubia results alone, it appears that there is a 

slight difference in the acute toxicity of the duplicate 

samples (WED and WEDII). Also, the arrival, initial, and 

final chemistry data show a difference in the characteristics 

in the ambient water between the two samples. Therefore, 

the duplicate analysis indicates that there is sufficient 

variability in the effluent stream to reflect a difference in 

the toxicity results of duplicate samples. However, this 

difference between duplicates is sufficiently small that the 

results of the acute toxicity tests, with LC50 as the 

endpoint, are not sensitive enough to calculate a coefficient 

of variation for effluent mine drainage samples. 

Representativeness 

For this project, representativeness for acute toxicity tests 

involved sample size, sampling times relative to seasonal 

temperature variation, and sampling locations. Most 

importantly, the changes due to seasonal environmental 

conditions needed to be documented to enable evaluation 

of zinc concentration reduction by biological conversion 

and uptake during cold stress conditions against warm 

temperature conditions. The QA goal was to obtain 

samples that represented biological water quality, measured 

by acute toxicity, in the treated and untreated mine 

drainage under typical seasonal environmental conditions. 

The primary seasonal environmental parameter of concern 

was temperature due to the regional extremes present at 

the demonstration location. 

Prior to the demonstration, it was known that three or four 

seasonal cycles would be required to conduct a statistical 

analysis of seasonal variation. The project budget and 

time schedule did not permit this type of data collection; 

consequently, the QA goal for representativeness 

was limited to successfully collecting data that would 

enable a limited evaluation of seasonal rise and fall 

of acute toxicity values in response to seasonal temperature 

stress. Since acute toxicity and zinc concentration data 

were obtained under environmental conditions 

representative of seasonal fluctuations in temperature in 

mine drainage influent and effluent, the QA objective for 

representativeness was met. 

Completeness 

Completeness is an assessment of the amount of valid 

data obtained from a measurement system compared to 

the amount of data expected to achieve a predefined 

quantity of information or level of confidence. The 

percent completeness is calculated by dividing the number 

of samples with acceptable data by the total number of 

samples planned to be collected and multiplying the result 

by 100. Greater than 90 percent completeness was 

achieved for all demonstration samples, and 100 percent 

of the critical samples for acute toxicity achieved 

acceptable results. 

Comparability 

The acute toxicity tests were conducted in accordance 

with the EPA guidance document “Methods for Measuring 

the Acute Toxicity of Effluents and Receiving Waters to 

Freshwater and Marine Organisms” (EPA 1991). All 

quality assurance guidance procedures have been adhered 

to, and the quantitative results for all QA criteria for 

reference toxicity fall within the specified limits. Therefore, 

the demonstration data are considered comparable to 

other acute toxicity data generated using these standard 

methods and adhering to the QA guidelines. 

4.3	 Noncritical Parameters Data Quality

Review 

Data quality review for the first noncrtical objective of 

substrate utilization, and the third noncritical objective of 

effluent impact to Clear Creek were included in the 

review for the number one critical objective data. Analytical 

results for these two noncritical parameters were within 

the quality assurance objectives stated in the Demonstration 

Plan (PRC 1995). 

Data quality results for noncritical objective number two, 

the metal removal by sulfate-reducing bacteria were 

within the parameters cited in the Demonstration Plan. 

As stated in the plan, the evaluation of sulfate-reduction 

was expected to be more qualitative in nature. Results for 

the bacteria counts and acid-volatile sulfides are considered 

acceptable quality. 

Specific data quality assurance objectives for the fourth, 

and final noncritical ojbective, compiled capital and 

50 
operating costs, were not stated in the Demonstration 

Plan. However, cost tracking and compilation was 

performed using a best professional judgment approach. 

These data are considered accurate and usable within 

accepted professional standards. 

51 
Section 5

Economic Analysis

This section presents cost estimates for using an anaerobic 

compost CWS system to treat mine drainage with water 

chemistry similar to the Burleigh Tunnel. The baseline 

scenario used for developing this cost estimate was a 50 

gpm flowrate, the total flow from the Burleigh Tunnel, and 

a 15-year system life. The baseline costs were then 

adjusted for flowrates of 25 gpm and 100 gpm to develop 

cost estimates for other cases. 

Cost estimates presented in this section are based primarily 

on data compiled during the SITE demonstration at the 

Burleigh Tunnel (CDPHE 1995). Additional cost data 

were obtained from standard engineering cost reference 

manuals (Means 1992). Costs have been assigned to 

11 categories applicable to typical cleanup activities at 

Superfund and RCRA sites (Evans 1990). Costs are 

presented in year 1995 dollars and are considered estimates, 

with an accuracy of plus 50 percent and minus 30 percent. 

5.1 Basis of Economic Analysis 

A number of factors affect the costs of treating mine 

drainage with an anaerobic compost CWS system. These 

factors generally include flow rate, type and concentration 

of contaminants, physical site conditions, geographical 

site location, and treatment goals. The characteristics of 

spent substrate produced by a CWS system will also 

affect disposal costs. Spent substrate will require off-site 

disposal. Mine drainage containing cadmium at 0.05 parts 

per million (ppm), iron at 50 ppm, nickel at 0.5 ppm, 

and zinc at 50 ppm was selected for this economic analysis. 

The following presents additional assumptions and 

conditions as they apply to each case. 

For each case, this analysis assumes that an upflow CWS 

system will treat contaminated mine drainage continuously, 

24 hours per day, 7 days per week. An average metals 

removal efficiency of 96 percent was assumed for all 

cases. Based on these assumptions, the CWS system will 

treat about 26.3 million gallons of water per year of 

operation at the baseline flowrate of 50 gpm. 

• Further assumptions about constructed wetlands

treatment for each case include the following: 

• A residence time of 75 to 150 hours is recommended 

for adequate metals removal. 

• A porosity of 50 percent is assumed for the substrate

material. 

• Two baseline wetlands, size of 90 feet by 90 feet by

4 feet (2,300 cubic yards [yd3

]), will provide a 78

hour residence time at a flowrate of 50 gpm (wetland

size is directly proportional to flowrate). Square

wetlands were used for the cost estimation; however, 

other shapes may be preferable. 

• Substrate material will require removal and

replacement once every 5 years. 

• The spent substrate is not a RCRA hazardous waste:

thus, it will be dewatered on site and can be recycled

or disposed of at an industrial landfill. 

• An aerobic polishing pond to increase displaced

oxygen is not required. 

This analysis assumes that aquatic-based standards are 

most appropriate; and the attainment of these standards 

depends on the affected organisms, receiving waters and 

volume of mine drainage. Attainment may not be feasible 

in all cases for the technology as tested during this 

demonstration. 

The following assumptions were also made for each case 

in this analysis: 

• The site is located within 200 miles of the disposal

location. 

• The site is located within 100 miles of a moderatesized city. 

52 
• The site will allow for gravity flow of the mine

drainage through the wetland. 

• A staging area is available for dewatering spent

substrate. 

• Access roads exist at the site. 

• Utilities, such as electricity and telephone lines, are

available on site. 

• The treatment goal for the site will be to reduce zinc

contaminant levels by 90 percent. 

• Spent substrate will be dewatered and disposed of

off site. 

• One influent water sample and two effluent water

samples will be collected monthly and two composite

substrate samples will be collected quarterly to

monitor system performance. 

• One part-time operator will be required to inspect

the system, collect all required samples, and conduct

minor maintenance and repairs. 

5.2 Cost Categories 

Cost data associated with the CWS technology have been 

assigned to one of the following 11 categories: (1) site 

preparation; (2) permitting and regulatory requirements; 

(3) capital equipment and construction; (4) startup; 

(5) labor; (6) consumables and supplies; (7) utilities; 

(8) residual and waste shipping and handling; (9) analytical 

services; (10) maintenance and modifications; and 

(11) demobilization. Costs associated with each category 

are presented in the sections that follow. Some sections 

end with a summary of significant costs within the category. 

Table 9 presents the cost breakdown for the flow variant 

cases. This table also presents total one-time, fixed costs, 

and total variable O&M costs; the total project costs; and 

the costs per gallon of water treated. 

5.2.1 Site Preparation Costs 

Site preparation includes administration, pilot-scale testing, 

mobilization costs. This analysis assumes a total area of 

about 65 acres will be needed to accommodate the 

wetland and staging area, construction equipment, and 

sampling and maintenance equipment storage areas. A 

solid gravel (or ground) surface is preferred for any 

remote treatment project. Pavement is not necessary, but 

the surface must be able to support construction equipment. 

This analysis assumes adequate surface areas exist at the 

site and that only moderate modifications will be required 

for wetland construction. 

Administrative costs, such as legal searches and access 

rights, are estimated to be an additional $10,000. 

Mobilization involves transporting all construction 

equipment and materials to the site. For this analysis, it is 

assumed that the site is located within 100 miles of a city 

where construction equipment is available. The total 

estimated mobilization cost will be $5,000. 

For each case, total site preparation costs are estimated 

to be $15,000. 

5.2.2 Permitting and Regulatory

Requirements 

Permitting and regulatory costs vary depending on whether 

treatment occurs at a Superfund site and on the disposal 

method selected for treated effluent and any solid wastes 

generated. At Superfund sites, remedial actions must be 

consistent with ARARs, environmental laws, ordinances, 

and regulations, including federal, state, and local standards 

and criteria. In general, ARARs must be identified on a 

site-specific basis. At an active mining site, a NPDES 

permit will likely be required and may require additional 

monitoring records and sampling protocols, which can 

increase permitting and regulatory costs. For this analysis, 

total permitting and regulatory costs are estimated to be 

$5,000. 

5.2.3 Capital Equipment 

Capital costs include all wetland construction and 

construction materials and a site building for housing 

sampling, monitoring, and maintenance equipment. 

Construction materials include sand, synthetic liners, 

geotextile liners, PVC piping, valves, concrete vaults or 

sumps, weirs, and other miscellaneous materials. Capital 

costs for the baseline wetland of 50 gpm are presented 

below. Site preparation and excavation include clearing 

the site of brush and trees, excavation of the wetland cell, 

grading the cell, and construction of the earthen berms. 

The total cost of site preparation and excavation is $19,500 

for the 50 gpm system. 

Construction of the wetland cell itself involves system 

design, subgrade preparation and installation of a sand 

layer, liner, piping distribution and collection systems, and 

the substrate. Also included is piping to and from the cell 

as well as system bypass piping, and concrete sumps with 

weirs at the influent of the wetland to control flow through 

53 
Table 9. CWS Costs for Different Treatment Flow Rates* 

Cost Categories 

System Life 15 Years 

25 gpm 50 gpm 100 gpm 

Fixed Costs 

Site Preparation $15,000 $15,000 $15,000 

Administrative $10,000 $10,000 $10,000 

Mobilization 5,000 5,000 5,000 

$5,000 $5,000 $5,000 

$215,300 $345,000 $604,500 

System Design $50,000 $50,000 $50,000 

Excavation and Site 

Preparation 9,800 19,500 39,000 

Wetland Cell Construction 120,000 240,000 480,000 

Piping and Valves 25,500 25,500 25,500 

Storage Building 10,000 10,000 10,000 

$1,500 $1,500 $1,500 

$52,250 $104,500 $209,000 

Excavation and Backfilling $10,000 $20,000 $40,000 

Substrate Disposal 42,250 84,500 169,000 

$316,000 $492,000 $844,000 

$153,000 $153,000 $153,000 

Operations Staff $153,000 $153,000 $153,000 

$39,000 $39,000 $39,000 

Personal Protective 

Equipment $39,000 $39,000 $39,000 

NA NA NA 

$120,000 $240,000 $480,000 

Substrate Disposal 40,000 (3) 80,000 (3) 160,000 (3) 

$360,000 $360,000 $360,000 

$247,550 $490,100 $975,200 

Annual Maintenance $5,000 $5,000 $5,000 

Substrate Removal and 

Replacement 80,850 (3) 161,700 (3) 323,400 (3) 

$919,550 $1,282,100 $2,007,200 

$1,235,500 $1,774,100 $2,851,200 

$0.0063 $0.0045 $0.0036 

Permitting and Regulatory

Requirements 

Capital Equipment 

Startup 

Demobilization 

Total Fixed Costs 

Variable Costs 

Labor 

Consumables and Supplies 

Utilities 

Residual and Waste Shipping and 

Handling 

Analytical Services 

Maintenance and Modifications 

Total Variable Costs 

Total Costs 

Total Cost Per Gallon Treated 

*Costs are based on July 1995 dollars, rounded to the nearest $100.

Substrate removal and replacement estimated to be necessary every5 years.

(3) Number of removals anticipated

NA Not applicable

54 
the system. The total cost for wetland cell construction of 

a 50 gpm system is $335.000. 

A small building is required for storing sampling equipment 

and providing work space for the system operator. The 

cost for a simple building with electricity has been estimated 

at $10,000. 

The total capital cost for a 50 gpm wetland system is 

$345,000. 

5.2.4 Startup 

Startup requirements are minimal for a wetland system. 

System startup involves introducing flow to the wetland 

with frequent inspections to verify proper hydraulic 

operation. Operators are assumed to be trained in health 

and safety procedures. Therefore, training costs are not 

incurred as a direct startup cost. The only costs directly 

related to system startup are labor costs associated with 

more frequent system inspection. Startup costs are 

estimated at $1,500. 

5.2.5 Labor 

Labor costs include a part-time technician to sample, 

operate, and maintain the system. Once the system is 

functioning, it is assumed to operate continuously at the 

design flow rate. One technician will monitor the system 

on a weekly basis. Weekly monitoring will require several 

hours 2 to 3 times per week to check flowrate and overall 

system operation. Sampling is assumed to be conducted 

once a month and will require two technicians for 2 hours. 

These requirements equate to 175 hours annually for 

general O&M. An additional 80 hours of labor are 

included for miscellaneous O&M and review of data. 

Based on $40 per hour for a technician, the annual cost for 

general labor O&M is $10,200. 

5.2.6 Consumables and Supplies 

The only consumables and supplies used during wetland 

operations are disposable PPE. Disposable PPE includes 

Tyvek coveralls, gloves, and bootcovers. The treatment 

system operator will wear PPE when required by health 

and safety plans during system operation. PPE will cost 

about $25 per day per person on site. Based on the 

assumed labor required above and an additional 22 days 

for miscellaneous O&M, PPE will be required 100 days 

annually, for an annual PPE cost of about $2,500. 

5.2.7 Utilities 

Utilities used by the wetland system are negligible. The 

wetland system requires no utilities for operation. The 

only utility required is for electricity for lights in the on-site 

storage building and for charging monitoring equipment. 

For this analysis, utility costs are assumed to be zero. 

5.2.8 Residual Waste Shipping and

Handling 

The residual waste for the wetland is assumed to be spent 

substrate. This analysis assumes that substrate will 

require removal and replacement once every 5 years. It 

is assumed that spent substrate will be dewatered on site 

and disposed of at a recycler or landfill. Substrate removal 

and replacement costs are covered in Section 5.2.11, 

maintenance and modifications. Loading dewatered 

substrate into 20 yd3

 haul trucks is estimated to cost 

$14,500. Hauling the substrate to a recycler or landfill 

is estimated to cost $28,000; disposal of substrate at 

the landfill costs $42,000. Oversight of substrate removal, 

hauling and replacement is expected to cost $3,200 (10 8-

hour days at $40/hr). Loading of the new substrate is 

expected to cost $12,000 and the cost of the substrate is 

$65,200. The total waste shipping and handling cost per 

substrate replacement is $161,700. Costs for residual 

waste shipping and handling are based solely on substrate 

volume. Costs for different sized wetlands are proportional 

to the 50 gpm baseline system described here. 

5.2.9 Analytical Services 

Analytical costs associated with a wetlands system include 

laboratory analysis, data reduction and tabulation, QA/ 

QC, and reporting. For each case, this analysis assumes 

that one influent sample and two effluent samples will be 

collected once a month and that two substrate samples 

will be collected quarterly. The substrate samples will be 

analyzed for total metals. Influent and effluent samples 

will be analyzed for total metals, ammonia, nitrate, 

phosphate, BOD, TSS, and TDS. Monthly laboratory 

analysis will cost about $1,050, and substrate analysis 

$3,500 per year. Data reduction, tabulation, QA/QC, and 

reporting are estimated to cost about $660 per month. 

Total annual analytical services for each case are estimated 

to cost about $24,000 per year. 

5.2.10 Maintenance and Modifications 

Annual repair and maintenance costs are expected to be 

minimal and for this analysis are assumed to be $5,000 for 

each case. No modification costs are assumed to be 

55 
incurred. The major maintenance cost will be removal 

and replacement of the substrate every 5 years. Excavation 

of substrate material has been estimated to cost $14,500 

for the 50 gpm scenario. Replacement of the distribution 

and collection piping was estimated to cost $14,300. 

Purchase and transport of new substrate was estimated 

to cost $65,400. The total estimated cost of substrate 

removal and replacement is $161,700. The removal and 

replacement cost will vary proportionally with the wetland 

size. 

5.2.11 Demobilization 

Site demobilization costs include excavation of the substrate 

and concrete vaults and weirs, disposal of substrate, and 

backfilling the wetland. For the 50 gpm scenario, excavation 

costs are estimated at $10,000. Substrate disposal costs 

are $80,000. Backfilling of the wetland is expected to cost 

$10,000, assuming native material from the original wetland 

excavation was left on site. The total demobilization cost 

is estimated to be $104,500. This cost will vary 

proportionally with wetland size. 

56 
Section 6 

Technology Status 

Currently, several hundred constructed and natural 

wetlands are treating coal mine drainage in the eastern 

United States. The effectiveness of these systems is 

discussed in several publications including Hammer 1989, 

Moshiri 1993, and the proceedings of annual meetings of 

the American Society for Surface Mining and Reclamation, 

and several U.S. Bureau of Mines papers (U.S. Bureau 

of Mines Special Publication SP066-4 and Information 

Circular IC 9389) (see Appendix B). 

In addition, any constructed wetlands designed to treat 

metal mine drainages have been constructed and tested or 

are being tested by EPA, various state agencies, and 

industry. In Colorado, the state Division of Minerals has 

constructed several wetland systems to treat metal mine 

drainage. Constructed wetlands treatment is also being 

considered for the full-scale remedy of the Burleigh 

Tunnel drainage. 

57 
Section 7

References

Camp, Dresser, and McKee (CDM). 1993. Clear Creek 

Remedial Design Passive Treatment at Burleigh

Tunnel, Draft Preliminary Design at Burleigh Tunnel.

June. 

Colorado Department of Public Health and Environment 

(CDPHE). 1995. Facsimile Communication with 

Garry Farmer, Tetra Tech. February, 1995. 

Correns, C.W. 1969. Introduction to Mineralogy.

Springer-Verlag. New York. Berlin. 

Environmental Restoration Unit Cost Book (ECHOS).

1995. ECHOS, Los Angeles, California. 

Evans, G. 1990. Estimating Innovative Technology Costs

for the SITE program. Journal of Air and Waste 

Management Association. 40:7:1047-1051. 

Gusek, J.J., and Wildeman, Dr. T. R.. 1995. New 

Developments in Passive Treatment of Acid Rock

Drainage. Paper presented at Engineering Foundation

Conference on Technological Solutions for Pollution

Prevention in the Mining and Mineral Processing

Industries, Palm Coast Florida, January 23, 1995. 

Gusek, J.J., J.T. Gormley, and J.W. Sheetz. 1994. 

Design and construction aspects of pilot-scale passive

treatment systems for acid rock drainage at metal

mines. Proc. Society of Chemical Industry

Symposium. Chapman and Hall, London. 

Hammer, D.A. 1989. Constructed Wetlands 

for Wastewater Treatment. Lewis Publishers. 

Chelsea, Michigan. 

Hedin, R.S., R.W. Narin, and R.L.P. Kleinmann. 1994. 

Passive Treatment of Coal Mine Drainage. United 

States Bureau of Mines Information Circular 9389. 

Klusman, R.W. 1993. Computer Code to Model

Constructed Wetlands for Aid in Engineering Design.

Report to United States Bureau of Mines, Contract

J0219003. 

Means, R.S. 1992. Means Building Construction

Cost Data. Construction Consultants and Publishers, 

Kingston, Massachusetts. 

Metcalf and Eddy, Inc. 1979. Wastewater Engineering

Treatment, Disposal, and Reuse. Revised by George

Tchobanoglous and Franklin L. Burton. McGrawHill Publishing Company. New York, New York. 

Moshiri, G.A. 1993. Constructed Wetlands for 

Water Quality Improvement. Lewis Publishers. 

Boca Raton, Florida. 

PRC Environmental Management, Inc. (PRC) 1993.

Colorado Department of Public Health and

Environment, Constructed Wetlands System

Treatability Study at the Burleigh Tunnel, Silver

Plume, Colorado, Treatability Study Work Plan,

Denver, Colorado, February 1993. 

PRC. 1995. Colorado Department of Public Health and

Environment Constructed Wetlands System

Demonstration Plan. July. 

Reynolds, J.S. 1991. Determination of the Rate of 

Sulfide Production by Sulfate-reducing Bacteria at

the Big 5 Wetland. Masters Thesis. Colorado 

School of Mines. Golden, Colorado. 

U.S. Bureau of Mines. 1994b. Proceedings of the

International Land Reclamation and Mine Drainage

Conference and Third International Conference on 

the Abatement of Acidic Drainage. Pittsburgh,

Pennsylvania, April 24-29, 1994, Bureau of Mines

Special Publication SP 066-4. 

U.S. Environmental Protection Agency (EPA). 1988. 

Constructed Wetlands and Aquatic Plant Systems

for Municipal Wastewater Office of Research and 

Development. Washington, D.C. EPA/625/1-88/

022. September. 

EPA. 1993a. Methods for Measuring the

Acute Toxicology of Effluents and Receiving Waters

to Freshwater and Marine Organisms. Office of

Research and Development. Washington, D.C.

EPA/600/4-90/027F. 4th Edition. September. 

EPA. 1993b. Handbook for Constructed 

Wetlands Receiving Acid Mine Drainage. Office of 

Research and Development. Cincinnati, OH. 

September. 

58 
Appendix A
 


Analytical Results Summary Tables
 


59
 
--

--

--

--

Table A-1. Influent Results 

INFLUENT
 


W I030994 W I032394 W I040694 W I042094 W I050594 W I051994 

ANALYTIC AL 03/09/94 03/23/94 04/06/94 04/20/94 05/05/94 05/19/94 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 ND ND ND ND ND 0.045 

ARSENIC 6020 ND 0.0041 0.0068 0.020 0.060 0.052 

CADMIUM 6020 0.10 0.099 0.10 0.10 0.098 0.081 

CALCIUM 6010 84.8 88.0 91.7 96.9 89.9 83.2 

IRON 6010 0.31 0.33 0.33 0.34 0.32 0.21 

LEAD 6020 0.014 0.015 0.014 0.016 0.016 0.014 

MAGNESIUM 6010 41.8 43.1 44.2 46.5 47.1 49.1 

MANGANESE 6010 2.3 2.4 2.5 2.6 2.3 1.8 

NICKEL 6010 0.045 0.039 0.042 0.047 0.043 0.035 

POT ASSIUM 6010 2.6 2.9 3.0 3.1 3.6 3.2 

SILVER 6020 0.0011 0.00012 0.000066 0.000070 0.000098 0.00019 

SODIUM 6010 10.3 9.3 10.9 9.1 14.0 10.5 

ZINC 6010 55.0 56.1 60.1 64.0 56.1 44.8 

ANIONS: 

SULFAT E 300.0 386 374 387 384 317 314 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 1.0 1.2 1.1 1.1 0.98 1.0 

CHLORIDE 300.0 19.9 21.8 22.3 21.9 19.0 15.0 

PHOSPHORUS, T OT AL 365.3 ND ND ND ND ND ND 

ORT HOPHOSPHAT E 365.3 ND 0.30 ND ND ND 0.40 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND 0.060 0.11 ND ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND 0.060 0.11 ND ND 

AMMONIA 350.1 ND ND ND ND ND ND 

TOTAL SOLIDS: 

T SS 160.2 16.8 8.8 20.4 15.2 7.4 8.4 

T DS 160.1 732 655 640 663 641 622 

T OC 9060 1.1 NA NA ND NA NA 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 100 107 105 107 104 107 

ALKALINIT Y, BICARB 

AS CAC03 310.1 100 107 105 107 104 107 

DISSOLVED OXYGEN (mg/L) 8.1 8.3 6.8* NA NA 

pH 7.4 7.5 7.5 7.4 7.5 

CONDUCT IVIT Y (μS) 730 745 745 699 698 

T EMP ERAT URE (degrees C) 6.9 7.3 7.3 8.9 9.4 

-- = Not applicable NA = Not analyzed 

μS = MicroSiemens ND = Not detected 

mg/L = Milligrams per liter 

60 
--

--

--

--

Table A-1 (continued). Influent Results 

INFLUENT
 

W I060194 W I062994 W I071394 W I072894 W I081594 W I082494 

ANALYTIC AL 06/01/94 06/29/94 07/13/94 07/28/94 08/15/94 08/24/94 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 ND 0.068 ND ND ND ND 

ARSENIC 6020 ND ND ND ND ND ND 

CADMIUM 6020 0.092 0.089 0.086 0.098 0.10 0.0952 

CALCIUM 6010 89.6 86.1 94.5 91.2 92.5 94.6 

IRON 6010 0.25 0.23 0.23 0.30 0.24 0.25 

LEAD 6020 0.020 0.017 0.013 0.017 0.016 0.014 

MAGNESIUM 6010 50.6 45.4 48.3 46.4 47.7 48.1 

MANGANESE 6010 1.9 2.1 2.2 2.2 2.3 2.4 

NICKEL 6010 0.033 0.045 0.044 0.043 0.042 0.046 

POT ASSIUM 6010 3.6 3.0 3.1 2.9 2.9 3.2 

SILVER 6020 0.00019 ND 0.00013 0.00015 0.00017 ND 

SODIUM 6010 13.2 12.8 13.00 12.0 14.4 15.3 

ZINC 6010 49.1 54.2 56.8 59.1 54.7 57.5 

ANIONS: 

SULFAT E 300.0 357 378 377 397 374 403 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 1.0 1.0 0.90 1.1 1.1 1.1 

CHLORIDE 300.0 16.9 17.9 17.5 18.7 18.6 19.6 

PHOSPHORUS, T OT AL 365.3 ND ND ND ND ND ND 

ORT HOPHOSPHAT E 365.3 ND 0.44 ND 0.077 ND ND 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND 2.0 1.7 1.9 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND ND 2.0 1.7 1.9 

AMMONIA 350.1 ND ND ND ND ND ND 

TOT AL SOLIDS: 

T SS 160.2 4.4 11.2 9.2 9.6 2.4 18.4 

T DS 160.1 657 680 685 707 759 703 

T OC 9060 NA NA NA NA NA NA 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 109 107 109 103 105 102 

ALKALINIT Y, BICARB 

AS CAC03 310.1 109 107 109 103 105 102 

DISSOLVED OXYGEN (mg/L) 8.7 NA 8.2 NA NA 7.6 

pH 7.6 7.57 7.5 NA 7.5 7.4 

CONDUCT IVIT Y (μS) 775 980 950 927 948 920 

T EMP ERAT URE (degrees C) 9.4 9.5 9.4 9.5 9.4 9.4 

** = Degrees Farenheit NA = Not analyzed
 

-- = Not applicable ND = Not detect ed
 

μS = microSiemens
 

mg/L= Milligrams per lit er
 

61 
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--

--

Table A-1 (continued). Influent Results 

INFLUENT

W I090794 WI091994 WI100494 WI101994 W I110294 WI112094 

ANALYTIC AL 09/07/94 09/19/94 10/04/94 10/19/1994 11/02/94 11/20/94 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUMINUM 6010 ND ND ND ND 0.030 ND 

ARSENIC 6020 ND ND ND ND ND ND 

CADMIUM 6020 0.098 0.085 0.089 .10 0.10 0.091 

CALCIUM 6010 90.2 89.7 92.6 92.4 89.2 93.5 

IRON 6010 0.29 0.29 0.31 0.25 0.28 0.32 

LEAD 6020 0.017 0.015 0.014 0.014 0.014 0.016 

MAGNESIUM 6010 46.5 46.6 47.3 46.7 46.2 47.3 

MANGANESE 6010 2.3 2.3 2.3 2.4 2.2 2.3 

NICKEL 6010 0.047 0.042 0.052 0.046 0.051 0.050 

POT ASSIUM 6010 3.9 3.1 3.0 3.0 2.9 3.1 

SILVER 6020 0.00040* 0.00041 0.00050 ND ND 0.00030 

SODIUM 6010 12.1 12.5 11.6 13 14.8 14.4 

ZINC 6010 56.4 57.6 59.7 57.6 56.5 58.2 

ANIONS: 

SULFAT E 300.0 416 404 400 409 410 407 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 1.0 1.0 1.0 ND 1.0 1.1 

CHLORIDE 300.0 20.2 19.6 19.8 19.5 20.1 21.3 

PHOSP HORUS, T OT AL 365.3 ND ND ND ND ND ND 

ORT HOPHOSP HAT E 365.3 ND ND ND ND 0.13 ND 

NIT RAT E P LUS NIT RIT E AS N 353.2 ND ND ND ND ND ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND ND ND ND ND 

AMMONIA 350.1 ND ND ND ND ND ND 

TOTAL SOLIDS: 

T SS 160.2 17.6 8.4 18.8 18.8 8.0 18.0 

T DS 160.1 711 723 695 695 709 711 

T OC 9060 NA NA NA NA NA NA 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 102 101 112 102 82.4 101 

ALKALINIT Y, BICARB 

AS CAC03 310.1 102 101 112 102 82.4 101 

DISSOLVED OXYGEN (mg/L) 9.5 7.8 NA NA NA NA 

pH 7.41 7.4 7.4 7.1 6.9 6.9 

CONDUCT IVIT Y (μS) 922 930 935 750 900 NA 

T EMP ERAT URE (degrees C) 9.3 9.3 9.1 8.5 8.7 8.1 

-- = Not applicable NA = Not det ected 

μS = MicroSiemens ND = Not det ected 

mg/L = Milligrams per lit er 

62 
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Table A-1 (continued). Influent Results 

INFLUENT
 

W I113094 W I121494 W I010495 W I011895 W I020195 W I021595 

ANALYTIC AL 11/30/94 12/14/94 01/04/95 01/18/95 02/01/95 02/15/95 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 ND 0.036 0.032 0.038 0.047 0.043 

ARSENIC 6020 ND ND ND ND ND ND 

CADMIUM 6020 0.086 0.092 0.82 0.076 0.089 0.084 

CALCIUM 6010 95.4 98.1 87.7 90.8 90.1 100.0 

IRON 6010 0.34 0.37 0.31 ND 0.34 0.39 

LEAD 6020 0.014 0.018 0.016 0.015 0.016 0.015 

MAGNESIUM 6010 47.7 48.9 46.5 45.4 44.1 49.4 

MANGANESE 6010 2.5 2.5 2.3 2.4 2.4 2.7 

NICKEL 6010 0.044 0.050 0.048 0.046 0.052 0.048 

POT ASSIUM 6010 2.8 3.3 2.9 3.0 2.8 3.5 

SILVER 6020 0.00036 ND 0.00037 0.00021 ND ND 

SODIUM 6010 14.2 19.5 15.0 15.9 14.1 20.4 

ZINC 6010 62.8 63.0 55.5 57.1 56.6 58.9 

ANIONS: 

SULFAT E 300.0 411 413 395 386 402 390 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 1.1 1.0 1.1 1.1 1.1 1.1 

CHLORIDE 300.0 21.4 21.2 21.6 21.7 22.5 22.8 

PHOSP HORUS, T OT AL 365.3 ND ND ND ND ND ND 

ORT HOP HOSPHAT E 365.3 0.13 0.36 ND ND ND 0.10 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND ND 1.7 ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND ND ND 7 1. ND 

AMMONIA 350.1 ND ND ND ND ND ND 

T OT AL SOLIDS: 

T SS 160.2 16.4 10.4 5.2 12.0 12.8 12.8 

T DS 160.1 711 687 689 693 694 656 

T OC 9060 NA NA NA NA NA NA 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 99.6 103 104 106 106 106 

ALKALINIT Y, BICARB 

AS CAC03 310.1 99.6 103 104 106 106 106 

DISSOLVED OXYGEN (mg/L) NA 8.0 8.5 7.3 7.6 NA 

pH 6.9 7.54 7.5 7.5 7.9 7.0 

CONDUCT IVIT Y (μS) 605 600 610 600 610 NA 

T EMP ERAT URE (degrees C) 7.9 8.0 6.5 9.0 7.9 8.1 

* = Dissolved met als NA = Not analyzed
 

-- = Not applicable ND = Not det ected
 

μS = Microsiemens
 

mg/L = Milligrams per lit er
 

63 
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--

--

Table A-1 (continued). Influent Results 

INFLUENT

W I022795 W I031595 W I032995 W I041295 W I042695 W I051095 

ANALYTIC AL 02/27/95 03/15/95 03/29/95 04/12/95 04/26/95 05/10/95 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 0.024 0.049 ND ND 0.060 0.15 

ARSENIC 6020 ND ND ND ND ND ND 

CADMIUM 6020 0.071 0.076 0.074 0.057 0.095 0.095 

CALCIUM 6010 92.6 91.4 85.2 90.9 88.2 92.0 

IRON 6010 0.33 0.36 0.33 0.32 0.41 0.48 

LEAD 6020 0.014 0.016 0.014 0.015 0.022 0.026 

MAGNESIUM 6010 45.1 44.4 41.9 42.9 41.2 41.9 

MANGANESE 6010 2.5 2.5 2.3 2.4 2.6 3.0 

NICKEL 6010 0.068 0.045 0.045 0.048 0.071 0.054 

POT ASSIUM 6010 2.9 2.9 2.8 3.0 2.9 3.1 

SILVER 6020 ND ND ND ND ND ND 

SODIUM 6010 16.2 15.8 16.4 16.1 14.2 14.8 

ZINC 6010 58.6 57.0 53.1 55.0 55.7 61.4 

ANIONS: 

SULFAT E 300.0 384.0 384.0 368.0 376.0 370.0 374 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 1.1 1.1 1.0 1.0 1.1 1.1 

CHLORIDE 300.0 22.6 22.4 23.1 22.4 23.8 20.5 

PHOSPHORUS, T OT AL 365.3 ND ND ND ND ND ND 

ORT HOPHOSPHAT E 365.3 ND ND ND 0.11 ND ND 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND ND 0.14 ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND ND ND 0.14 ND 

AMMONIA 350.1 ND ND ND ND ND ND 

TOTAL SOLIDS: 

T SS 160.2 11.2 9.2 12.8 14.4 7.2 2.8 

T DS 160.1 692 672 655 656 575 689 

T OC 9060 NA NA NA NA NA ND 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 107 104 107 107 104 103 

ALKALINIT Y, BICARB 

AS CAC03 310.1 107 104 107 107 104 103 

DISSOLVED OXYGEN (mg/L) 7.8 NA 7.5 8.6 7.5 

pH 7.4 7.5 7.7 7.5 NA 

CONDUCT IVIT Y (μS) 630 620 600 620 600 

T EMPERAT URE (degrees C) 8.6 9.3 8.1 8.4 9.0 

* = Dissolved met als NA = Not analyzed
 

-- = Not applicable ND = Not detect ed
 

μS = Microsiemens
 

mg/L = Milligrams per liter
 

64 
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--

--

Table A-1 (continued). Influent Results 

INFLUENT
 

W I061295 W I062895 W I071095 W I072695 W I080895 WI082395 

ANALYTIC AL 6/12/1995 6/28/1995 7/10/1995 7/26/1995 8/8/1995 8/23/1995 

ANALYTE METHO D mg/L mg/L m g/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 0.065 ND ND ND ND 0.079 

ARSENIC 6020 ND ND ND ND ND ND 

CADMIUM 6020 0.25 0.26 0.25 0.24 0.26 0.240 

CALCIUM 6010 94.4 111 119 129 123 125 

IRON 6010 0.12 0.11 0.10 ND 0.15 0.19 

LEAD 6020 0.058 0.051 0.050 0.038 0.043 0.039 

MAGNESIUM 6010 58.3 61.4 64.0 64.2 61.7 61.3 

MANGANESE 6010 3.9 4.4 5.0 5.5 5.2 5.2 

NICKEL 6010 0.061 0.073 0.081 0.084 0.093 0.086 

POT ASSIUM 6010 4.1 ND 3.6 3.7 3.5 3.2 

SILVER 6020 ND ND ND ND ND ND 

SODIUM 6010 9.9 14.2 14.8 13.2 14.1 15.2 

ZINC 6010 75.5 86.8 99.8 105 109 108 

ANIONS: 

SULFAT E 300.0 499 502 582 596 638 630 

SULFIDE T OT AL 376.2 

FLUORIDE 340.2 0.8 0.89 0.96 0.88 0.87 0.95 

CHLORIDE 300.0 6.9 8.8 10.2 11.7 13.1 

P HOSPHORUS, T OT AL 365.3 ND ND ND ND ND 0.093 

ORT HOPHOSPHAT E 365.3 ND ND ND ND 0.095 ND 

NIT RAT E PLUS NIT RIT E AS N 353.2 0.13 0.10 ND 0.63 ND ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 0.13 ND ND 0.63 ND ND 

AMMONIA 350.1 ND ND ND ND ND ND 

TOTAL SOLIDS: 

T SS 160.2 20.4 20.4 24.8 22.4 18.8 32.0 

T DS 160.1 838 967 1010 999 10.0 1050 

T OC 9060 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 120 125 118 107 107 107 

ALKALINIT Y, BICARB 

AS CAC03 310.1 120 125 118 107 107 107 

DISSOLVED OXYGEN (mg/L) NA 7.1 NA NA NA NA 

pH 7.4 7.2 7.4 NA NA NA 

CONDUCT IVIT Y (μS) NA 700 NA NA 750 NA 

T EMPERAT URE (degrees C) 10.2 10.3 10.3 NA 10.4 NA 

* = Dissolved metals NA = Not analyzed
 

-- = Not applicable ND = Not detect ed
 

μS = Microsiemens
 

mg/L = Milligrams per liter
 

65 
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--

--

Table A-1 (continued). Influent Results 

INFLUENT

ANALYTE ANALYTIC AL W I090595 W I110995 C DPHE C DPHE C DPHE C DPHE 

METHO D 9/5/1995 11/9/1995 1/29/1996 2/29/1996 4/25/1996 5/31/1996 

mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 ND ND NA NA NA NA 

ARSENIC 6020 ND ND NA NA NA NA 

CADMIUM 6020 0.24 0.20 0.160 0.200 0.12 0.14 

CALCIUM 6010 123 113 NA NA NA NA 

IRON 6010 0.28 0.18 0.24 0.26 0.18 0.17 

LEAD 6020 0.038 0.027 NA NA NA NA 

MAGNESIUM 6010 60.2 56.2 NA NA NA NA 

MANGANESE 6010 5.2 5.2 3.60 3.50 2.4 2.7 

NICKEL 6010 0.087 0.082 NA NA NA NA 

P OT ASSIUM 6010 ND 3.2 NA NA NA NA 

SILVER 6020 ND ND NA NA NA NA 

SODIUM 6010 12.4 15.6 NA NA NA NA 

ZINC 6010 107 105 73 69 46 56 

ANIONS: 

SULFAT E 300.0 652 591 490 450 NA NA 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 0.88 0.97 NA NA NA NA 

CHLORIDE 300.0 NA 17.7 NA NA NA NA 

P HOSP HORUS, T OT AL 365.3 0.067 0.060 NA NA NA NA 

ORT HOP HOSPHAT E 365.3 ND 0.20 NA NA NA NA 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND NA NA NA NA 

NIT RIT E AS N 354.1 ND ND NA NA NA NA 

NIT RAT E AS N 353.2/354.1 ND ND NA NA NA NA 

AMMONIA 350.1 ND ND NA NA NA NA 

TOTAL SOLIDS: 

T SS 160.2 18.4 14.4 NA NA NA NA 

T DS 160.1 1050 956 NA NA NA NA 

T OC 9060 NA NA NA 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 107 95.7 NA NA NA NA 

ALKALINIT Y, BICARB NA NA NA NA 

AS CAC03 310.1 107 95.7 NA NA NA NA 

DISSOLVED OXYGEN (mg/L) NA NA NA NA 

pH NA NA NA NA 

CONDUCT IVIT Y (μS) NA NA NA NA 

T EMPERAT URE (degrees C) NA NA NA NA 

* = Dissolved metals NA = Not analyzed
 

-- = Not applicable ND = Not detect ed
 

μS = Microsiemens
 

mg/L = Milligrams per lit er
 

66 
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--

--

--

Table A-1 (continued). Influent Results 

INFLUENT
 

C DPHE CDPHE C DPHE W I120996 WI012197 W I022097 

ANALYTIC AL 6/14/1996 7/19/1996 8/31/1996 12/9/1996 1/21/1997 2/20/1997 

ANALYTE METHO D m g/L mg/L m g/L mg/L m g/L mg/L 

AQ UEO US ALUMINUM 6010 NA NA NA ND ND ND 

ARSENIC 6020 NA NA NA NA NA NA 

CADMIUM 6020 0.16 0.19 0.20 0.15 0.12 0.11 

CALCIUM 6010 NA NA NA 104 100.0 105 

IRON 6010 0.18 0.20 0.24 0.30 0.30 0.33 

LEAD 6020 NA NA NA NA NA NA 

MAGNESIUM 6010 NA NA NA 52.8 51.2 52 

MANGANESE 6010 2.9 3.5 4.1 3.7 3.5 3.7 

NICKEL 6010 NA NA NA 0.07 0.06 0.06 

P OT ASSIUM 6010 NA NA NA 3.1 J 3.0 J 3.0 J 

SILVER 6020 NA NA NA NA NA NA 

SODIUM 6010 NA NA NA 17.4 16.4 17.0 

ZINC 6010 60 71 84 78 74 78 

ANIONS: 

SULFAT E 300.0 430 490 520 488 491 471 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 NA NA NA NA NA NA 

CHLORIDE 300.0 NA NA NA 17.8 18.2 18.3 

P HOSP HORUS, T OT AL 365.3 NA NA NA NA NA NA 

ORT HOP HOSP HAT E 365.3 NA NA NA 0.31 0.17 0.22 

NIT RAT E P LUS NIT RIT E AS N 353.2 NA NA NA ND ND ND 

NIT RIT E AS N 354.1 NA NA NA ND ND ND 

NIT RAT E AS N 353.2/354.1 NA NA NA ND ND ND 

AMMONIA 350.1 NA NA NA ND ND ND 

TOTAL SOLIDS: 

T SS 160.2 NA NA NA NA 8.4 3.2 

T DS 160.1 NA NA NA 849 796 809 

T OC 9060 NA NA NA 0.8J 1.1 1.8 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 NA NA NA 97.6 94.9 101 

ALKALINIT Y, BICARB NA NA NA 

AS CAC03 310.1 NA NA NA 97.6 94.9 101 

DISSOLVED OXYGEN (mg/L) NA NA NA 7.4 8.8 8.6 

pH NA NA NA 7.2 5.1 7.5 

CONDUCT IVIT Y (μS) NA NA NA NA NA NA 

T EMPERAT URE (degrees C) NA NA NA 10.0 8.2 3.2 

* = Dissolved met als NA = Not analyzed
 

-- = Not applicable ND = Not det ect ed
 

μS = Microsiemens
 

mg/L= Milligrams per lit er
 

67 
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--

--

--

Table A-1 (continued). Influent Results 

INFLUENT
 

W I032097 W I042297 W I052897 W I062397 W I082897 W I093097 

ANALYTIC AL 3/20/1997 4/22/1997 5/28/1997 6/23/1997 8/28/1997 9/30/1997 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 ND 0.17 ND ND ND ND 

ARSENIC 6020 NA NA NA NA NA NA 

CADMIUM 6020 0.14 0.07 0.11 0.19 0.22 0.200 

CALCIUM 6010 97.5 67.2 86.4 95.6 121 119 

IRON 6010 0.34 0.34 0.24 0.26 0.3 0.33 

LEAD 6020 NA NA NA NA NA NA 

MAGNESIUM 6010 48.8 37.3 53.8 52.3 61.9 58.4 

MANGANESE 6010 3.6 2.0 2.7 3.3 4.9 4.9 

NICKEL 6010 0.07 0.034 J 0.042 0.030 J 0.090 0.098 

POT ASSIUM 6010 ND 2.7 J 3.3 J 3.5 J 4.8 J 3.4 J 

SILVER 6020 NA NA NA NA NA NA 

SODIUM 6010 15.6 ND 14.9 ND ND 18.3 

ZINC 6010 75 42 56 72 104 104 

ANIONS: 

SULFAT E 300.0 476 279 358 428 541 568 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 NA NA NA NA NA NA 

CHLORIDE 300.0 18.7 9.3 7.2 9.2 13.8 16 

PHOSPHORUS, T OT AL 365.3 NA NA NA NA NA NA 

ORT HOPHOSPHAT E 365.3 0.15 ND ND 0.10 ND ND 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND 0.14 ND 0.14 ND 0.19 

NIT RIT E AS N 354.1 0.0021 J 0.0046 J 0.0024 J 0.0028 J 0.0037 J ND 

NIT RAT E AS N 353.2/354.1 ND ND ND ND ND ND 

AMMONIA 350.1 ND ND ND ND ND ND 

TOTAL SOLIDS: 

T SS 160.2 7.6 1.6 J 12.4 14.4 16.4 

T DS 160.1 751 507 653 765 927 940 

T OC 9060 0.20 J 1.30 1.4 0.98 J 0.80 J 0.58 J 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 96.3 99.7 107 121 102 

ALKALINIT Y, BICARB 

AS CAC03 310.1 96.3 99.7 107 121 102 

DISSOLVED OXYGEN (mg/L) 7.8 7.3 7.3 8 8.7 NA 

pH 6.9 7.4 7.4 7.5 6.9 6.9 

CONDUCT IVIT Y (μS) NA NA NA NA NA NA 

T EMPERAT URE (degrees C) 8.6 9.7 10.5 9.7 9.6 9.4 

* = Dissolved met als NA = Not analyzed
 

-- = Not applicable ND = Not detect ed
 

μS = Microsiemens
 

mg/L = Milligrams per lit er
 

68 
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--

--

Table A-1 (continued). Influent Results 

INFLUENT
 

W I102997 W I112597 

ANALYTIC AL 10/29/1997 11/25/1997 

ANALYTE METHO D mg/L mg/L 

AQ UEO US ALUMINUM 6010 ND ND 

ARSENIC 6020 NA NA 

CADMIUM 6020 0.19 0.22 

CALCIUM 6010 113 103 

IRON 6010 0.37 0.39 

LEAD 6020 NA NA 

MAGNESIUM 6010 58.8 50.4 

MANGANESE 6010 4.9 4.2 

NICKEL 6010 0.079 0.065 

P OT ASSIUM 6010 3.4 J ND 

SILVER 6020 NA NA 

SODIUM 6010 18.3 16.5 

ZINC 6010 95 86 

ANIONS: 

SULFAT E 300.0 571 548 

SULFIDE T OT AL 376.2 NA NA 

FLUORIDE 340.2 NA NA 

CHLORIDE 300.0 17.5 17.8 

P HOSP HORUS, T OT AL 365.3 NA NA 

ORT HOPHOSPHAT E 365.3 ND 0.15 

NIT RAT E P LUS NIT RIT E AS N 353.2 0.11 ND 

NIT RIT E AS N 354.1 0.002J 0.0025J 

NIT RAT E AS N 353.2/354.1 NA NA 

AMMONIA 350.1 ND ND 

TOTAL SOLIDS: 

T SS 160.2 10.4 14.8 

T DS 160.1 940 869.0 

T OC 9060 0.71J 1.8 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 84 102 

ALKALINIT Y, BICARB 

AS CAC03 310.1 84 102 

DISSOLVED OXYGEN (mg/L) 10.3 7.5 

pH 7.2 7.2 

CONDUCT IVIT Y (μS) NA NA 

T EMP ERAT URE (degrees C) 9.2 8.9 

* = Dissolved met als NA = Not analyzed 

-- = Not applicable ND = Not det ected 

μS = Microsiemens 

mg/L= Milligrams per lit er 

69 
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--

--

DOWNFLOW EFFLUENT
 

WED030994 WED032394 WED040694 WED042094 WED050594 

ANALYTICAL 03/09/94 03/23/94 04/06/94 04/20/94 05/05/94 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUM INUM 6010 0.021 0.021 0.027 0.029 0.033 

ARSENIC 6020 ND 0.00056 0.029 0.016 0.076 

CADM IUM 6020 0.00034 0.00025 0.00028 0.00053 0.00072 

CALCIUM 6010 105.0 107.0 110.0 113.0 113.0 

IRON 6010 1.5 1.2 1.1 1.0 1.1 

LEAD 6020 0.0015 0.0012 0.00065 0.0015 0.0017 

M AGNESIUM 6010 56.7 56.9 58.6 58.3 58.9 

M ANGANESE 6010 1.6 1.5 1.5 1.4 1.4 

NICKEL 6010 0.0073 0.0081 0.0086 0.010 0.0090 

POTASSIUM 6010 55.8 56.6 54.0 50.6 48.3 

SILVER 6020 0.0015 0.00012 0.000060 0.000089 0.0051 

SODIUM 6010 19.0 17.1 18.1 15.3 18.6 

ZINC 6010 14.2 14.9 15.6 15.3 13.1 

ANIONS: 

SULFATE 300.0 350 357 338 337 280 

SULFIDE TOTAL 376.2 4.1 5.2 5.7 2.1 0.74 

FLUORIDE 340.2 0.82 0.93 0.88 0.90 0.87 

CHLORIDE 300.0 15.6 28.4 27.2 28 22 

PHOSPHORUS, TOTAL 365.3 9.9 10.6 11.0 10.8 10.4 

ORTHOPHOSPHATE 365.3 10.6 12.4 10.7 11.1 11.1 

NITRATE PLUS NITRITE AS N 353.2 0.24 ND ND ND ND 

NITRITE AS N 354.1 ND ND ND ND ND 

NITRATE AS N 353.2/354.1 0.24 ND ND ND ND 

AM M ONIA 350.1 5.4 6.2 5.9 5.8 4.6 

TOTAL SOLIDS: 

TSS 160.2 51.0 27.0 47.0 39.2 3.8 

TDS 160.1 864 781 766 783 753 

TOC 9060 60.4 20.6 29 28.2 20.8 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 193 209 200 213 193 

ALKALINITY, BICARB 

AS CAC03 310.1 193 209 200 213 193 

ORP (mV) -77.0 -180 -184 

pH 7.3 7.2 7.6 

CONDUCTIVITY (μS) 845 889 803 

TEM PERATURE (degrees C) 4.1 5.2 8.8 

-- = Not ap plicable NA = Not analy zed
 

μS = M icroSiemens ND = Not detected
 

mg/L = M illigrams per liter
 

mV = M illivolts
 

Table A-2. Downflow Effluent Results 

70 
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--

--

Table A-2 (continued). Downflow Effluent Results 

DOWNFLOW EFFLUENT
 


WED051994 WED060194 WED062994 WED071394 WED072894 WED081594 

ANALYTICAL 05/19/94 06/01/94 06/29/94 07/13/94 07/28/94 08/15/94 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUM INUM 6010 0.024 0.030 0.017 0.012 0.017 0.016 

ARSENIC 6020 0.066 0.0013 0.0011 0.0010 0.0012 0.0011 

CADM IUM 6020 0.0011 0.00073 ND ND ND 0.00033 

CALCIUM 6010 107.0 112.0 106.0 118.0 116.0 114.0 

IRON 6010 1.0 1.1 1.0 1.1 1.1 1.3 

LEAD 6020 0.0013 0.0011 ND ND ND ND 

M AGNESIUM 6010 57.1 60.8 55.2 57.9 55.9 56.6 

M ANGANESE 6010 1.3 1.4 1.5 1.8 1.8 2.1 

NICKEL 6010 0.0088 0.015 0.014 0.0089 0.013 0.013 

POTASSIUM 6010 39.5 29.2 19.8 20.8 17.8 23.0 

SILVER 6020 0.000063 ND 0.00010 0.00025 ND 0.00014 

SODIUM 6010 15.4 15.2 13.8 14.7 14.5 15.5 

ZINC 6010 9.9 10.3 12.6 15.3 16.5 14.5 

ANIONS: 

SULFATE 300.0 270 319 338 337 354 311 

SULFIDE TOTAL 376.2 3.2 2.4 2.1 1.3 6.9 1.5 

FLUORIDE 340.2 0.91 0.95 0.80 0.90 1.1 1.0 

CHLORIDE 300.0 17.4 18.4 19.6 17.8 19.8 19.2 

PHOSPHORUS, TOTAL 365.3 11.4 10.1 8.9 9.5 7.8 8.7 

ORTHOPHOSPHATE 365.3 10.6 9.2 8.6 8.6 7.5 6.7 

NITRATE PLUS NITRITE AS N 353.2 ND ND ND ND 2.3 1.7 

NITRITE AS N 354.1 ND ND ND ND ND ND 

NITRATE AS N 353.2/354.1 ND ND ND ND 2.3 1.7 

AM M ONIA 350.1 4.4 3.2 2.3 3.1 2.9 3.2 

TOTAL SOLIDS: 

TSS 160.2 ND 3.6 33.6 43 45.6 43.2 

TDS 160.1 739 741 709 722 747 759 

TOC 9060 26.3 35.6 17.8 15.9 15.4 15.6 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 196 208 188 190 188 194 

ALKALINITY, BICARB 

AS CAC03 310.1 196 208 188 190 188 194 

ORP (mV) -271 -253 -250 NA NA 

pH 7.28 7.10 7 NA 7.06 

CONDUCTIVITY (μS) 812 1040 1010 996 1006 

TEM PERATURE (degrees C) 12.2 12.3 11.6 11.8 12.1 

-- = Not applicable NA = Not analy zed
 

μS = M icroSiemens ND = Not detected
 

mg/L = M illigrams per liter
 

mV = M illivolts
 

71 
Table A-2 (continued). Downflow Effluent Results 

DOWNFLOW EFFLUENT
 


WED082494 WED090794 WED091994 WED100494 WED101994 WED110294 

ANALYTICAL 08/24/94 09/07/94 09/19/94 10/04/94 10/19/1994 11/02/94 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUM INUM 6010 0.015 0.053 0.022 0.037 0.018 0.023 

ARSENIC 6020 0.0011 ND 0.0011 0.0018 ND ND 

CADM IUM 6020 0.00030 ND ND 0.00038 0.00048 0.00041 

CALCIUM 6010 117.0 113.0 124.0 115.0 112.0 112.0 

IRON 6010 1.7 1.8 2.0 1.8 1.7 1.8 

LEAD 6020 ND 0.0016 0.0023 0.0032 ND ND 

M AGNESIUM 6010 57.5 55.8 63.9 57.6 57.7 58.0 

M ANGANESE 6010 2.2 2.0 2.2 1.9 1.8 1.6 

NICKEL 6010 0.014 0.013 0.020 0.019 0.020 0.020 

POTASSIUM 6010 21.7 25.0 24.9 21.6 19.5 16.8 

SILVER 6020 ND 0.00032* 0.00034 0.0012 ND ND 

SODIUM 6010 15.6 14.5 16.4 14.4 14.5 15.5 

ZINC 6010 15.3 15.2 17.5 15.5 14.2 12.1 

ANIONS: 

SULFATE 300.0 345 349 349 333 353 365 

SULFIDE TOTAL 376.2 4.5 0.12 5.3 10.7 4.8 7.4 

FLUORIDE 340.2 1.0 0.94 0.96 0.88 0.85 0.87 

CHLORIDE 300.0 21.3 22.3 21.0 21.0 20.3 20.8 

PHOSPHORUS, TOTAL 365.3 10.4 1.6 9.1 8.8 9.0 8.2 

ORTHOPHOSPHATE 365.3 7.9 8.6 13.8 8.5 8.4 8.8 

NITRATE PLUS NITRITE AS N 353.2 1.8 ND ND ND ND ND 

NITRITE AS N 354.1 ND ND ND ND ND ND 

NITRATE AS N 353.2/354.1 1.8 ND ND ND ND ND 

AM M ONIA 350.1 3.2 2.6 2.5 2.9 2.2 1.5 

TOT AL SOLIDS: 

TSS 160.2 48.8 49.6 47.2 52.0 45.6 40.0 

TDS 160.1 713 741 738 716 698 734 

TOC 9060 13.8 12.3 10.3 9.7 8.1 5.0 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 191 194 184 200 174 152 

ALKALINITY, BICARB 

AS CAC03 310.1 191 194 184 200 174 152 

ORP (mV) -- -125 -163 -216 -220 -331 -149 

pH -- 6.88 6.91 6.9 6.9 6.66 6.92 

CONDUCTIVITY (μS) -- 973 997 1010 960 750 890 

TEM PERATURE (degrees C) -- 13.4 12.4 10.7 9.0 6.8 4.9 

-- = Not applicable NA = Not analy zed
 

μS = M icroSiemens ND = Not detected
 

mg/L = M illigrams per liter
 

mV = M illivolts
 

72 
--

--

--

--

Table A-2 (continued). Downflow Effluent Results 

DOWNFLOW EFFLUENT
 

WED112094WED113094WED121494WED010495WED011895WED020195 

ANALYTICAL 11/20/94 11/30/94 12/14/94 01/04/95 01/18/95 02/01/95 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUM INUM 6010 0.018 0.023 0.013 0.013 0.014 0.022 

ARSENIC 6020 ND ND ND 0.0039 0.0035 ND 

CADM IUM 6020 0.00030 0.00030 0.00088 ND ND ND 

CALCIUM 6010 120.0 118.0 120.0 117.0 119.0 115.0 

IRON 6010 1.8 2.4 2.0 2.7 3.0 2.6 

LEAD 6020 0.0054 0.0018 0.011 ND 0.0012 ND 

M AGNESIUM 6010 60.6 58.0 56.6 57.1 54.5 50.7 

M ANGANESE 6010 1.6 1.7 1.5 1.9 1.9 1.8 

NICKEL 6010 0.019 0.019 0.017 0.013 0.014 0.018 

POTASSIUM 6010 16.0 13.1 11.5 9.7 9.9 8.3 

SILVER 6020 ND 0.00022 ND ND ND ND 

SODIUM 6010 14.6 14.5 15.0 14.3 14.9 15.0 

ZINC 6010 10.9 11.7 8.8 8.3 9.7 10.5 

ANIONS: 

SULFATE 300.0 357 391 391 386 386 380 

SULFIDE TOTAL 376.2 0.11 5.8 3.1 3.3 1.6 2.3 

FLUORIDE 340.2 0.90 1.1 0.99 1.1 1.0 1.0 

CHLORIDE 300.0 21.0 22.0 21.2 22.1 22.1 21.9 

PHOSPHORUS, TOTAL 365.3 6.5 7.2 7.3 6.6 6.4 6.3 

ORTHOPHOSPHATE 365.3 3.1 5.0 6.2 5.5 4.9 6.0 

NITRATE PLUS NITRITE AS N 353.2 ND ND ND ND ND ND 

NITRITE AS N 354.1 ND ND ND ND ND ND 

NITRATE AS N 353.2/354.1 ND ND ND ND ND ND 

AM M ONIA 350.1 2.2 2.0 0.41 1.6 1.5 1.3 

TOTAL SOLIDS: 

TSS 160.2 41.0 40.5 28.5 34.0 37.0 33.0 

TDS 160.1 750 767 744 729 718 721 

TOC 9060 6.9 20.4 5.7 4.8 5.6 4.8 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 187 143 152 146 141 129 

ALKALINITY, BICARB 

AS CAC03 310.1 187 143 152 146 141 129 

ORP (mV) -170 -220 -195 -20.0 -6.5 -7.3 

pH 7.6 7.12 7.46 7.26 7.6 7.6 

CONDUCTIVITY (μS) NA 600 600 590 590 670 

TEM PERATURE (degrees C) 3.7 3.0 2.9 3.3 3.0 4.0 

-- = Not ap plicable NA = Not analyzed
 

μS = M icroSiemens ND = Not detected
 

mg/L = M illigrams per liter
 

mV = M illivolts
 

73 
Table A-2 (continued). Downflow Effluent Results 

DOWNFLOW EFFLUENT
 

WED021595 WED022795 WED031595 WED032995WED041295 WED042695 

ANALYTICAL 02/15/95 02/27/95 03/15/95 03/29/95 04/12/95 04/26/95 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEO US ALUM INUM 6010 0.018 0.011 0.011 ND 0.014 ND* 

ARSENIC 6020 0.0011 0.0019 ND ND 0.0021 ND 

CADM IUM 6020 0.00033 ND ND ND ND ND 

CALCIUM 6010 116.0 121.0 126.0 103.0 113.0 109.0 

IRON 6010 2.4 2.1 2.2 1.8 1.8 1.7 

LEAD 6020 0.0010 ND ND ND ND ND 

M AGNESIUM 6010 51.2 52.5 54.3 46.0 48.1 46.6 

M ANGANESE 6010 1.9 1.9 2.1 1.8 1.9 1.9 

NICKEL 6010 0.016 0.015 0.018 0.019 0.014 0.014 

POTASSIUM 6010 8.4 8.5 9.0 6.9 6.7 6.9 

SILVER 6020 ND ND ND ND ND ND 

SODIUM 6010 15.9 15.1 16.5 14.7 14.1 14.1 

ZINC 6010 10.7 11.7 13.0 12.2 12.6 11.9 

ANIONS: 

SULFATE 300.0 359 346 370 341 338 341 

SULFIDE TOTAL 376.2 1.9 1.9 3.1 3.1 0.099 1.6 

FLUORIDE 340.2 1.1 1.0 1.1 1.1 1.0 1.1 

CHLORIDE 300.0 22.1 22.7 24.4 22.5 21.8 23.8 

PHOSPHORUS, TOTAL 365.3 17.5 5.9 5.7 5.2 4.7 4.7 

ORTHOPHOSPHATE 365.3 5.1 5.8 5.7 3.8 5.4 2.4 

NITRATE PLUS NITRITE AS N 353.2 ND ND ND ND ND ND 

NITRITE AS N 354.1 ND ND ND ND ND ND 

NITRATE AS N 353.2/354.1 ND ND ND ND ND ND 

AM M ONIA 350.1 1.2 1.2 1.5 1.3 1.1 1.1 

TOTAL SOLIDS: 

TSS 160.2 32.4 34.0 33.0 31.0 35.0 31.2 

TDS 160.1 679 723 707 662 655 651 

TOC 9060 4.3 5.5 5.4 5.8 6.9 6.8 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 140 152 152 141 143 141 

ALKALINITY, BICARB 

AS CAC03 310.1 140 152 152 141 143 141 

ORP (mV) -- 59.0 -82.0 -65.0 -81.1 35.0 NA 

p H -- 8.8 7.1 7.1 7.3 7.2 NA 

CONDUCTIVITY (μS) -- NA 620 680 580 580 600 

TEM PERATURE (degrees C) -- 2.8 5.6 6.8 5.6 4.8 7.0 

-- = Not ap p licable NA = Not analy zed
 

μS = M icroSiemens ND = Not detected
 

mg/L = M illigrams per liter
 

mV = M illivolts
 

74 
DOWNFLOW EFFLUENT
 

WED051095WED061295WED062895WED071095WED072695WED080895 

ANALYTICAL 05/10/95 6/12/1995 6/28/1995 7/10/1995 7/26/1995 8/8/1995 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUM INUM 6010 ND* ND ND ND ND 0.015 

ARSENIC 6020 ND ND ND ND ND ND 

CADM IUM 6020 ND ND ND ND ND ND 

CALCIUM 6010 121.0 125 142 144 157 148 

IRON 6010 2.1 4.2 3.9 3.9 2.9 2.8 

LEAD 6020 ND ND ND ND ND ND 

M AGNESIUM 6010 47.8 52.7 61.9 68.7 71.7 68.6 

M ANGANESE 6010 2.4 3.9 4.4 4.1 4.1 3.8 

NICKEL 6010 0.016 0.017 0.020 0.021 0.020 0.022 

POTASSIUM 6010 6.5 6.8 7.1 8.2 7.6 6.8 

SILVER 6020 ND ND ND ND ND ND 

SODIUM 6010 14.1 8.7 10.6 12.8 12.6 12.5 

ZINC 6010 13.3 26.5 31.2 30.8 29.7 33.1 

ANIONS: 

SULFATE 300.0 348.0 425 453 525 537 535 

SULFIDE TOTAL 376.2 0.38 0.054 6.9 5.7 0.83 10.0 

FLUORIDE 340.2 1.1 0.87 0.80 0.96 0.86 0.91 

CHLORIDE 300.0 22.6 7.0 7.2 8.6 10.1 11.1 

PHOSPHORUS, TOTAL 365.3 4.3 3.7 4.7 3.5 2.6 2.5 

ORTHOPHOSPHATE 365.3 4.1 2.2 1.5 3.7 2.0 1.6 

NITRATE PLUS NITRITE AS N 353.2 ND ND ND ND ND ND 

NITRITE AS N 
 354 1 . ND ND ND ND ND ND 

NITRATE AS N 
 353.2/354.1 ND ND ND ND ND ND 

AM M ONIA 350.1 0.96 0.90 0.94 1.0 0.50 0.64 

TOTAL SOLIDS: 

TSS 160.2 29.2 43.0 53.6 48.0 28.0 38.8 

TDS 160.1 707 763 918 946 959 1090 

TOC 9060 4.4 6.6 11.4 5.4 7.2 4.7 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 137 129 195 146 141 

ALKALINITY, BICARB 129 195 
 

AS CAC03 
 310.1 137 146 141 

ORP (mV) -80 -68 -52 14 

pH 6.8 6.6 6.7 7.1 

CONDUCTIVITY (μS) NA 720 NA 850 

TEM PERATURE (degrees C) 11.7 12.3 13.8 14.1 

* - Aluminum was re-analyzed 6/2/95 due to blank contamination 

-- = Not applicable mV = M illivolts 

μS = M icroSiemens NA = Not analyzed 

mg/l = M illigrams per liter ND = Not detected 

Table A-2 (continued). Downflow Effluent Results 

75 
Table A-2 (continued). Downflow Effluent Results 

DOWNFLOW EFFLUENT
 

WED082395WED090595 WED110995 CDPHE CDPHE CDPHE 

ANALYTICAL 8/23/1995 9/5/1995 11/9/1995 1/29/1996 2/29/1996 4/25/1996 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUM INUM 6010 ND 0.016 ND NA NA NA 

ARSENIC 6020 ND ND ND NA NA NA 

CADM IUM 6020 ND ND 0.00030 0.00012 0.00072 0.15 

CALCIUM 6010 155 147 149 NA NA NA 

IRON 6010 2.7 2.2 2.4 NA 0.28 1.7 

LEAD 6020 ND ND 0.0016 NA NA NA 

M AGNESIUM 6010 70.2 66.3 66.2 NA NA NA 

M ANGANESE 6010 3.9 3.7 4.0 3.2 3.0 2.2 

NICKEL 6010 0.026 0.028 0.04 NA NA NA 

POTASSIUM 6010 6.2 6.2 5.3 NA NA NA 

SILVER 6020 ND ND ND NA NA NA 

SODIUM 6010 13.7 12.5 14.5 NA NA NA 

ZINC 6010 34.1 29.1 34.5 28 26 15 

ANIONS: 

SULFATE 300.0 539 529 535 440 430 318 

SULFIDE TOTAL 376.2 11.4 5.6 3.8 NA NA NA 

FLUORIDE 340.2 0.85 0.82 0.81 NA NA NA 

CHLORIDE 300.0 12.2 14 17.3 NA NA NA 

PHOSPHORUS, TOTAL 365.3 3.0 2.8 2.5 NA NA NA 

ORTHOPHOSPHATE 365.3 3.0 1.3 1.1 NA NA NA 

NITRATE PLUS NITRITE AS N 353.2 ND ND ND NA NA NA 

NITRITE AS N 354.1 0.0070 ND ND NA NA NA 

NITRATE AS N 353.2/354.1 ND ND ND NA NA NA 

AM M ONIA 350.1 0.78 0.64 0.39 1.0 1.1 1.1 

T OTAL SOLIDS: 

TSS 160.2 50.0 45.6 12.8 NA NA NA 

TDS 160.1 996 941 957 NA NA NA 

TOC 9060 4.2 4.9 4.2 NA NA NA 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 143 179 152 NA NA NA 

ALKALINITY, BICARB 

AS CAC03 310.1 143 179 152 NA NA NA 

ORP (mV) -60 NA NA NA 

pH 6.7 NA NA NA 

CONDUCTIVITY (μS) 750 NA NA NA 

TEM PERATURE (degrees C) 4.7 NA NA NA 

-- = Not ap p licable NA = Not analy zed
 

μS = M icroSiemens ND = Not detected
 

mg/L = M illigrams p er liter
 

mV = M illivolts
 

76 
Table A-2 (continued). Downflow Effluent Results 

DOWNFLOW EFFLUENT
 

CDPHE CDPHE CDPHE CDPHE WED012197WED022097 

ANALYTICAL 5/31/1996 6/14/1996 7/19/1996 8/31/1996 1/21/1997 2/20/1997 

ANALYTE METHOD mg/L mg/L mg/L mg/L mg/l mg/l 

AQUEOUS ALUM INUM 6010 NA NA NA NA 0.098 ND 

ARSENIC 6020 NA NA NA NA NA NA 

CADM IUM 6020 0.00016 ND 0.00021 0.00013 0.016 0.034 

CALCIUM 6010 NA NA NA NA 115 113 

IRON 6010 0.87 0.92 1.10 1.60 0.53 0.72 

LEAD 6020 NA NA NA NA 57.3 56.9 

M AGNESIUM 6010 NA NA NA NA 3.3 5.0 

M ANGANESE 6010 1.8 2.00 2.10 2.20 NA NA 

NICKEL 6010 NA NA NA NA 0.05 0.035 

POTASSIUM 6010 NA NA NA NA 0.39 3.80 

SILVER 6020 NA NA NA NA NA NA 

SODIUM 6010 NA NA NA NA 16.6 16 

ZINC 6010 11 9.7 8.7 5.8 55 59.7 

ANIONS: 

SULFATE 300.0 230 82 340 350 421 322 

SULFIDE TOTAL 376.2 NA NA NA NA 0.13 ND 

FLUORIDE 340.2 NA NA NA NA NA NA 

CHLORIDE 300.0 NA NA NA NA 18.6 18.6 

PHOSPHORUS, TOTAL 365.3 NA NA NA NA NA NA 

ORTHOPHOSPHATE 365.3 NA NA NA NA 1.1 0.54 

NITRATE PLUS NITRITE AS N 353.2 NA NA NA NA ND 0.2 

NITRITE AS N 354.1 NA NA NA NA 0.0025 0.0055 

NITRATE AS N 353.2/354.1 NA NA NA NA NA NA 

AM M ONIA 350.1 0.67 1.2 0.90 ND 0.24 0.20 

TOTAL SOLIDS: 

TSS 160.2 NA NA NA NA 7.2 6.0 

TDS 160.1 NA NA NA NA 787 752 

TOC 9060 NA NA NA NA 7.2 25.8 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 NA NA NA NA 158 259 

ALKALINITY, BICARB 

AS CAC03 310.1 NA NA NA NA 158 259 

ORP(mV) NA NA NA NA 110 92.0 

pH NA NA NA NA 5.3 7.0 

CONDUCTIVITY (uS) NA NA NA NA NA NA 

TEMPERATURE (degrees C) NA NA NA NA 1.8 1.8 

-- = Not applicable NA = Not analyzed 

μS = MicroSiemens ND = Not detected 

mg/L = Milligrams per liter 

mV = Millivolts 

77 
Table A-3. Upflow Effluent Results 

UPFLOW EFFLUENT 

W EU030994 W EU032394 W EU040694 W EU042094 W EU050594 W EU051994 

ANALYTIC AL 03/09/94 03/23/94 04/06/94 04/20/94 05/05/94 05/19/94 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 
 0.077 0.20 0.078 0.39 0.062 0.028 

ARSENIC 6020 
 0.0062 0.0071 0.036 0.028 0.085 0.067 

CADMIUM 6020 
 0.00042 0.00049 0.00034 0.00036 0.00024 0.00020 

CALCIUM 6010 
 75.3 96.2 112.0 115.0 123.0 115.0 

IRON 6010 
 0.48 0.61 0.48 0.99 0.27 0.25 

LEAD 6020 
 0.0042 0.0030 0.0038 0.020 0.0022 0.0015 

MAGNESIUM 6010 
 72.7 71.4 69.3 63.1 66.0 60.1 

MANGANESE 6010 
 0.051 0.072 0.065 0.16 0.17 0.25 

NICKEL 6010 
 0.0054 0.0071 0.0095 0.0086 0.0086 0.0086 

POT ASSIUM 6010 
 223.0 188.0 150.0 108.0 91.2 49.4 

SILVER 6020 
 0.0014 0.00015 0.000084 0.00048 0.000071 0.000072 

SODIUM 6010 
 33.9 31.2 27.3 21.8 22 
 16.8 

ZINC 6010 
 0.22 0.22 0.13 0.43 0.14 0.32 

ANIONS: 

SULFAT E 300.0 354 
 388 
 364 
 343 
 292 
 265 
 

SULFIDE T OT AL 
 376.2 0.38 7.9 9.4 1.9 0.47 2.4 

FLUORIDE 340.2 0.30 0.57 0.62 0.72 0.71 0.88 

CHLORIDE 300.0 83.2 76.0 59.7 50.0 35.5 21.8 

PHOSPHORUS, T OT AL 365.3 24.3 23.2 20.5 20.8 18.3 17.6 

ORT HOPHOSPHAT E 365.3 26.8 26.7 20.9 20.6 18.6 15.9 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND 0.060 ND ND ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND 0.060 ND ND ND 

AMMONIA 350.1 23.8 19.6 15.0 12.9 10.5 6.8 

TOTAL SOLIDS: 

T SS 160.2 6 
 12.0 6.0 25.2 ND ND 

T DS 160.1 1390 
 1200 
 1110 
 1010 
 934 
 804 
 

T OC 
 9060 
 264 
 51.3 60.0 49.3 35.6 23.8 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 367 
 347 
 310 
 308 
 265 
 230 
 

ALKALINIT Y, BICARB 
 

AS CAC03 
 310.1 367 
 347 
 310 
 308 
 265 
 230 
 

ORP (mV) 
 -- -377 -280 -269 -271 

pH -- 8 
 7.85 7.20 7.84 

CONDUCT IVIT Y (μS) -- 1410 
 1222 
 954 
 893 
 

T EMP ERAT URE (degrees C) 
 -- 5 
 6.0 7.8 8.8 

-- = Not applicable NA = Not analyzed
 

μ/s = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

78
 
Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

W EU060194 W EU062994 W EU071394 W EU072894 W EU081594 W EU082494 

ANALYTIC AL 06/01/94 06/29/94 07/13/95 07/28/95 08/15/94 08/24/94 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 0.045 0.021 ND 0.38 0.015 0.023 

ARSENIC 6020 ND ND ND ND ND ND 

CADMIUM 6020 ND ND ND ND ND ND 

CALCIUM 6010 117 120 132 132 134 132 

IRON 6010 0.26 0.47 0.79 1.4 2.7 3.3 

LEAD 6020 0.0030 0.0017 ND ND ND ND 

MAGNESIUM 6010 61.5 61.7 61.4 58.6 58.3 57.1 

MANGANESE 6010 0.33 0.79 1.3 1.7 2.1 2.3 

NICKEL 6010 0.014 0.011 0.0052 0.0075 0.0089 0.0077 

POT ASSIUM 6010 37.3 24.2 17.3 13.7 12.8 11.3 

SILVER 6020 ND 0.00014 0.00015 ND 0.00021 ND 

SODIUM 6010 15.7 15.6 15 14.2 14.4 14.4 

ZINC 6010 0.20 0.35 0.18 0.29 0.38 0.58 

ANIONS: 

SULFAT E 300.0 330 355 372 356 369 392 

SULFIDE T OT AL 376.2 5 3.2 0.59 1.5 0.69 1.0 

FLUORIDE 340.2 0.81 0.90 0.80 1.0 0.96 1.1 

CHLORIDE 300.0 22.2 20.9 18.9 20.2 19.9 20.5 

PHOSPHORUS, T OT AL 365.3 27.3 12.8 13.3 10.8 10.5 9.8 

ORT HOPHOSPHAT E 365.3 14.9 21.3 19.5 10.5 7.8 9.2 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND 1.9 1.7 1.8 

NIT RIT E AS N 354.1 ND ND ND ND 0.077 ND 

NIT RAT E AS N 353.2/354.1 ND ND ND 1.9 1.7 1.8 

AMMONIA 350.1 5.6 3.0 3.0 2.6 1.6 1.3 

TOTAL SOLIDS: 

T SS 160.2 ND 2.4 2.0 18.8 7.6 27.2 

T DS 160.1 808 759 766 816 802 767 

T OC 9060 28.0 11.4 9.0 9.6 8.8 6.0 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 244 220 211 206 194 183 

ALKALINIT Y, BICARB 

AS CAC03 310.1 244 220 211 206 194 183 

ORP (mV) -- -275 -280 NA NA -344 

pH -- 7.7 7.6 NA 7.6 7.46 

CONDUCT IVIT Y (μS) -- 1115 1090 1049 1069 1037 

T EMP ERAT URE (degrees C) -- 9.7 9.4 9.7 9.4 10.0 

-- = Not applicable NA = Not analyzed
 

μ/s = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

79 
Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

W EU090794W EU090794E B W EU091994 W EU100494 W B5100494 W EU101994 

ANALYTIC AL 09/07/94 09/07/94 09/19/94 10/04/94 10/04/94 10/19/94 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQUEOUS ALUMINUM 6010 0.052 ND 0.023 0.017 6.1 0.015 

ARSENIC 6020 ND ND ND 0.0011 0.0021 0.0011 

CADMIUM 6020 ND ND ND ND 0.024 ND 

CALCIUM 6010 126 0.15 132 127 344 128 

IRON 6010 4.3 ND 5.1 5.7 92.7 5.6 

LEAD 6020 0.0011 ND 0.0015 ND 0.020 ND 

MAGNESIUM 6010 53.3 ND 56.6 54.5 139.0 54.1 

MANGANESE 6010 2.4 ND 2.6 2.4 28.6 2.7 

NICKEL 6010 0.0083 ND 0.015 0.015 0.20 0.019 

POT ASSIUM 6010 10.2 ND 9.0 11.9 7.4 7.7 

SILVER 6020 0.00011* ND* 0.00046 0.00052 0.00099 ND 

SODIUM 6010 13.6 ND 14.2 13.8 46.8 14.6 

ZINC 6010 0.82 0.019 1.4 2.4 9.4 3.1 

ANIONS: 

SULFAT E 300.0 395 ND 391 369 1760 392 

SULFIDE T OT AL 376.2 0.12 ND 0.23 5.0 NS 1.3 

FLUORIDE 340.2 1.0 ND 1.1 0.99 1.0 0.95 

CHLORIDE 300.0 21.1 ND 20.4 21.4 6.0 20.2 

PHOSPHORUS, T OT AL 365.3 1.6 ND 7.9 8.0 NS 6.8 

ORT HOPHOSPHAT E 365.3 8.8 ND 9.8 7.1 ND 6.8 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND ND NS ND 

NIT RIT E AS N 354.1 ND ND ND ND ND 0.018 

NIT RAT E AS N 353.2/354.1 ND ND ND ND NS ND 

AMMONIA 350.1 1.0 ND 0.87 1.0 NS 0.51 

TOTAL SOLIDS: 

T SS 160.2 27.6 ND 28.8 37.6 49.6 40.8 

T DS 160.1 787 ND 790 750 2520 734 

T OC 9060 6.4 ND 5.8 7.4 NS 5.3 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 175 ND 164 182 ND 150 

ALKALINIT Y, BICARB 

AS CAC03 310.1 175 ND 164 182 ND 150 

ORP (mV) -- -315 -267 -260 NA -344 

pH -- 7.39 7.3 7.3 5.2 6.95 

CONDUCT IVIT Y (μS) -- 1007 990 960 NA 760 

T EMPERAT URE (degrees C) -- 9.3 9.2 8.7 15.0 7.7 

-- = Not applicable NA = Not analyzed
 

μ/s = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

80 
Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

ANALYTE ANALYTIC AL W EU101994DW EU110294 W EU112094 W EU113094 WEU121494 W EU010495 

METHO D 10/19/94 11/02/94 11/20/94 11/30/94 12/14/94 01/04/95 

mg/L mg/L mg/L mg/l mg/L mg/L 

AQ UEO US ALUMINUM 6010 0.025 0.025 0.012 0.013 0.015 0.020 

ARSENIC 6020 ND 0.0011 0.0011 0.0014 0.0010 0.0035 

CADMIUM 6020 ND ND ND ND ND ND 

CALCIUM 6010 130 122 127 123 127 116 

IRON 6010 5.7 7.0 6.0 7.5 6.8 6.3 

LEAD 6020 ND ND ND ND ND ND 

MAGNESIUM 6010 54.8 52.5 53.8 51.4 52.4 53.1 

MANGANESE 6010 2.7 2.7 2.8 2.9 2.9 2.7 

NICKEL 6010 0.018 0.018 0.016 0.018 0.016 0.012 

POT ASSIUM 6010 7.6 11.6 9.6 7.6 7.6 15.3 

SILVER 6020 ND ND 0.00082 0.00028 ND 0.00033 

SODIUM 6010 15 14.2 14.7 14.5 15.6 14.5 

ZINC 6010 3.2 6.8 6.5 7.9 9.0 11.7 

ANIONS: 

SULFAT E 300.0 380 371 360 379 375 341 

SULFIDE T OT AL 376.2 1.8 3.8 3.8 4.6 3.2 3.3 

FLUORIDE 340.2 0.97 1.1 1.0 1.2 1.1 1.1 

CHLORIDE 300.0 20.0 23.2 23.0 22.2 22.4 25.6 

PHOSPHORUS, T OT AL 365.3 6.9 6.2 5.5 6.9 5.3 4.8 

ORT HOPHOSPHAT E 365.3 6.2 5.9 2.7 2.7 4.7 3.0 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND ND ND ND 

NIT RIT E AS N 354.1 0.017 0.016 ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND ND ND ND ND 

AMMONIA 350.1 0.52 0.38 0.74 0.55 1.5 0.68 

TOT AL SOLIDS: 

T SS 160.2 36.8 52.0 49.0 47.0 44.0 51.0 

T DS 160.1 742 727 745 729 729 707 

T OC 9060 5.6 9.4 7.3 19.1 6.4 12.5 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 148 141 185 142 157 171 

ALKALINIT Y, BICARB 

AS CAC03 310.1 148 141 185 142 157 171 

ORP (mV) -- -344 -164 -160 -216 -196 -80 

pH -- 6.95 7.01 7.2 6.8 7.33 7.0 

CONDUCT IVIT Y (μS) -- 760 935 NA 640 670 670 

T EMP ERAT URE (degrees C) -- 7.7 8.5 8.1 7.1 7.7 7.0 

-- = Not applicable NA - Not applicable
 

μs = MicroSiemens ND - Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

81 
--

--

--

--

Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT 

W EU011895 WEU020195 WEU021595 WEU022795 W EU031595 W EU032995

ANALYTIC AL 01/18/95 02/01/95 02/15/95 02/27/95 03/15/95 03/29/95

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L

AQ UEO US ALUMINUM 6010 0.026 0.017 0.012 0.014 0.012 0.015 

ARSENIC 6020 0.0043 0.0015 0.0020 0.0021 0.0012 0.0012 

CADMIUM 6020 ND ND ND ND ND ND 

CALCIUM 6010 116 119 119 116 116 105 

IRON 6010 5.4 4.9 4.3 4.0 4.0 3.5 

LEAD 6020 0.0034 ND ND ND ND ND 

MAGNESIUM 6010 49.5 49.0 49.1 48.2 48.2 44.6 

MANGANESE 6010 2.6 2.5 2.5 2.4 2.4 2.2 

NICKEL 6010 0.012 0.016 0.016 0.016 0.019 0.019 

POT ASSIUM 6010 10.5 9.1 9.1 8.9 7.5 5.9 

SILVER 6020 ND ND ND ND ND ND 

SODIUM 6010 15 16.7 16 15.2 16.0 15.7 

ZINC 6010 12.5 16.9 12.9 17.8 18.0 17.5 

ANIONS: 

SULFAT E 300.0 347 330 308 340 335 317 

SULFIDE T OT AL 376.2 3.0 6.0 3.3 4.3 2.7 4.3 

FLUORIDE 340.2 1.1 1.0 1.1 1.0 1.1 1.1 

CHLORIDE 300.0 23.0 23.4 23.4 23.6 24.3 23.0 

PHOSPHORUS, T OT AL 365.3 4.7 5.5 13.3 3.4 4.1 3.4 

ORT HOP HOSP HAT E 365.3 3.0 5.0 3.7 3.0 2.6 1.8 

NIT RAT E P LUS NIT RIT E AS N 353.2 ND 1.4 ND ND ND ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND 1.4 ND ND ND ND 

AMMONIA 350.1 0.63 0.52 0.51 0.34 0.38 0.31 

TOT AL SOLIDS: 

T SS 160.2 51.0 54.0 45.2 47.0 39.0 41.0 

T DS 160.1 693 692 682 700 671 667 

T OC 9060 7.8 6.8 6.2 5.8 4.3 7.0 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 168 161 191 150 151 154 

ALKALINIT Y, BICARB 

AS CAC03 310.1 168 161 191 150 151 154 

ORP (mV) 5 -11.7 -44.0 -65 -63 -81.1 

pH 7.1 7.4 7.2 6.9 6.9 7.3 

CONDUCT IVIT Y (μS) 650 610 NA 680 650 580 

TEMPERAT URE (degrees C) 3 8. 1 6. 6 7. 4 8. 8 8. 6 5. 

-- = Not applicable NA = Not analyzed
 

μS = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

82 
--

--

--

--

Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

WEU041295 WEU042695 W EU051095 WEU061295 WEU062895 WEU071095

ANALYTIC AL 04/12/95 04/26/95 05/10/95 06/12/95 6/28/1995 7/10/1995

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L

AQ UEO US ALUMINUM 6010 0.013 ND* ND* 0.028 ND ND 

ARSENIC 6020 0.0028 ND ND ND ND ND 

CADMIUM 6020 ND 0.00078 0.0094 0.0084 0.0045 ND 

CALCIUM 6010 114 106 110 103 121 130 

IRON 6010 3.5 2.2 2.2 4.6 3.7 3.8 

LEAD 6020 ND ND 0.0019 0.0018 ND ND 

MAGNESIUM 6010 46.5 45.3 44.5 45.2 60.2 68.2 

MANGANESE 6010 2.5 2.0 2.5 3 4.0 4.1 

NICKEL 6010 0.013 0.015 0.022 0.019 0.026 0.026 

POT ASSIUM 6010 7.1 11.7 18.1 7.5 6.0 5.4 

SILVER 6020 ND ND ND ND ND ND 

SODIUM 6010 15.3 14.2 13.3 8.9 11.2 13.2 

ZINC 6010 15.9 18.5 26.7 33.5 47.1 50.8 

ANIONS: 

SULFAT E 300.0 326 326 355 326 494 514 

SULFIDE T OT AL 376.2 0.39 2.9 1.3 0.065 1.5 1.5 

FLUORIDE 340.2 1.0 1.1 1.2 0.90 0.90 0.96 

CHLORIDE 300.0 22.5 26.0 25.9 7.6 7.0 8.3 

PHOSPHORUS, T OT AL 365.3 3.0 3.2 2.0 2.3 1.2 1.5 

ORT HOPHOSPHAT E 365.3 2.7 1.6 2.4 1.5 0.34 0.48 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND ND ND ND 

NIT RIT E AS N 354.1 ND ND ND ND ND ND 

NIT RAT E AS N 353.2/354.1 ND ND ND ND ND ND 

AMMONIA 350.1 0.33 0.31 0.42 0.36 0.20 0.20 

TOTAL SOLIDS: 

T SS 160.2 41.9 31.2 29.0 47.3 18.8 25.6 

T DS 160.1 657 607 724 668 885 944 

T OC 9060 8.0 8.3 9.9 9.1 4.9 4.8 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 152 147 138 181 136 147 

ALKALINIT Y, BICARB 

AS CAC03 310.1 152 147 138 181 136 147 

ORP (mV) -7.0 NA -57 

pH 7.1 NA 6.7 6.9 6.9 

CONDUCT IVIT Y (μS) 620 620 NA 

T EMPERAT URE (degrees C) 8.5 8.0 10.1 

* - Aluminum was re-analyzed 6/2/95 due to blank contamination
 

-- = Not applicable NA = Not analyzed
 

μS = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

83 
--

--

--

--

Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

WEU072695 WEU080895 WEU082395 W EU090595 W EU110995 C DPHE

ANALYTIC AL 7/26/1995 8/8/1995 8/23/1995 9/5/1995 11/9/1995 1/29/1996

ANALYTE METHO D mg/L m g/L mg/L mg/L mg/L mg/L

AQ UEO US ALUMINUM 6010 ND ND ND ND ND NA 

ARSENIC 6020 ND ND ND ND ND NA 

CADMIUM 6020 0.0060 0.0046 0.0093 0.010 0.04400 0.037 

CALCIUM 6010 144 135 141 137 133 NA 

IRON 6010 2.5 2.5 2.1 1.8 0.93 1.6 

LEAD 6020 ND ND ND ND 0.0022 NA 

MAGNESIUM 6010 68.6 64.4 66.1 64.3 62.1 NA 

MANGANESE 6010 4.1 3.8 3.8 3.6 4.4 3.3 

NICKEL 6010 0.028 0.032 0.036 0.04 0.059 NA 

P OT ASSIUM 6010 5.7 4.9 4.5 ND 4.3 NA 

SILVER 6020 ND ND ND ND ND NA 

SODIUM 6010 12.2 13.3 14.0 12.2 15.6 NA 

ZINC 6010 53.2 56.6 59.8 59.9 73.6 47 

ANIONS: 

SULFAT E 300.0 549 584 561 569 559 460 

SULFIDE T OT AL 376.2 4.3 3.5 5.2 2.8 0.84 NA 

FLUORIDE 340.2 0.89 0.88 0.90 0.86 0.96 NA 

CHLORIDE 300.0 10.0 11.2 12.5 13.7 17.1 NA 

PHOSPHORUS, T OT AL 365.3 1.1 1.1 1.3 1.5 0.69 NA 

ORT HOPHOSPHAT E 365.3 1.0 0.9 1.2 0.43 0.80 NA 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND ND ND NA 

NIT RIT E AS N 354.1 ND ND 0.0080 ND ND NA 

NIT RAT E AS N 353.2/354.1 ND ND ND ND ND NA 

AMMONIA 350.1 0.11 ND 0.21 ND ND 0.2 

T OT AL SOLIDS: 

T SS 160.2 16.8 17.6 30.0 26 5.2 NA 

T DS 160.1 961 999 1010 978 932 NA 

T OC 9060 5.7 3.4 3.2 3.7 2.1 NA 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 135 138 149 160 115 NA 

ALKALINIT Y, BICARB 

AS CAC03 310.1 135 138 149 160 115 NA 

ORP (mV) 

pH 6.8 7.1 7.1 6.9 7.0 NA 

CONDUCT IVIT Y (μS) NA 

T EMPERAT URE (degrees C) NA 

-- = Not applicable NA = Not analyzed
 

μS = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

84 
--

--

--

--

Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

C DPHE C DPHE C DPHE C DPHE C DPHE C DPHE 

ANALYTIC AL 2/29/1996 4/25/1996 5/31/1996 6/14/1996 7/19/1996 8/31/1996 

ANALYTE METHO D mg/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 NA NA NA NA NA NA 

ARSENIC 6020 NA NA NA NA NA NA 

CADMIUM 6020 0.035 0.030 0.140 0.031 0.051 0.053 

CALCIUM 6010 NA NA NA NA NA NA 

IRON 6010 1.3 0.81 0.17 1.1 0.87 0.90 

LEAD 6020 NA NA NA NA NA NA 

MAGNESIUM 6010 NA NA NA NA NA NA 

MANGANESE 6010 3.1 2.3 2.7 2.2 2.6 2.5 

NICKEL 6010 NA NA NA NA NA NA 

POT ASSIUM 6010 NA NA NA NA NA NA 

SILVER 6020 NA NA NA NA NA NA 

SODIUM 6010 NA NA NA NA NA NA 

ZINC 6010 42 31 56 30 41 43.0 

ANIONS: 

SULFAT E 300.0 430 329 420 310 410 45 

SULFIDE T OT AL 376.2 NA NA NA NA NA NA 

FLUORIDE 340.2 NA NA NA NA NA NA 

CHLORIDE 300.0 NA NA NA NA NA NA 

PHOSPHORUS, T OT AL 365.3 NA NA NA NA NA NA 

ORT HOPHOSPHAT E 365.3 NA NA NA NA NA NA 

NIT RAT E PLUS NIT RIT E AS N 353.2 NA NA NA NA NA NA 

NIT RIT E AS N 354.1 NA NA NA NA NA NA 

NIT RAT E AS N 353.2/354.1 NA NA NA NA NA NA 

AMMONIA 350.1 0.4 0.3 ND 0.2 0.2 ND 

TOTAL SOLIDS: 

T SS 160.2 NA NA NA NA NA NA 

T DS 160.1 NA NA NA NA NA NA 

T OC 9060 NA NA NA NA NA NA 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 NA NA NA NA NA NA 

ALKALINIT Y, BICARB 

AS CAC03 310.1 NA NA NA NA NA NA 

ORP (mV) NA NA NA NA NA NA 

pH NA NA NA NA NA NA 

CONDUCTIVITY (μS) NA NA NA NA NA NA 

T EMP ERAT URE (degrees C) NA NA NA NA NA NA 

-- = Not applicable NA = Not analyzed
 

μS = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

85 
--

--

--

--

Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

WEU120996 WEU012197 WEU022097 W EU031997 WEU042297

ANALYTIC AL 12/09/96 01/21/97 02/20/96 03/19/97 04/22/97 04/22/97

ANALYTE METHO D mg/L mg/L mg/L m g/L mg/L mg/L

AQ UEO US ALUMINUM 6010 ND ND ND ND ND ND (D) 

ARSENIC 6020 NA NA NA NA NA NA 

CADMIUM 6020 0.088 0.032 0.057 0.034 0.015 0.015 (D) 

CALCIUM 6010 115 116 119 109 95.9 97.3 (D) 

IRON 6010 0.99 1.2 0.8 1.1 0.98 0.99 (D) 

LEAD 6020 NA NA NA NA NA NA 

MAGNESIUM 6010 53.4 52.8 55.4 47.8 43.2 43.9 (D) 

MANGANESE 6010 2.9 2.7 3 2.8 2 2 (D) 

NICKEL 6010 0.035 J 0.032 J 0.033 J 0.041 0.021 J 0.021 J (D) 

P OT ASSIUM 6010 3.6 J 3.5 J 4.4 ND 4.6 J 4.6 J 

SILVER 6020 NA NA NA NA NA NA 

SODIUM 6010 15.3 15.5 15.7 14.4 7.3 7 (D) 

ZINC 6010 46 41.3 48.6 38 22.7 22.9 (D) 

ANIONS: 

SULFAT E 300.0 434 400 413 392 252 248 (D) 

SULFIDE T OT AL 376.2 0.8 1.2 0.71 0.037 J 3.5 3.6 (D) 

FLUORIDE 340.2 NA NA NA NA NA NA 

CHLORIDE 300.0 17.4 18.1 19.4 18.5 12.4 12.2 (D) 

P HOSP HORUS, T OT AL 365.3 NA NA NA NA NA NA 

ORT HOPHOSPHAT E 365.3 0.84 1.7 1.1 2 1.7 1.8 (D) 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND ND ND 0.020 J ND (D) 

NIT RIT E AS N 354.1 ND 0.0057 J 0.0055 J 0.0058 J 0.0038 J .0036 J (D) 

NIT RAT E AS N 353.2/354.1 NA NA NA NA NA NA 

AMMONIA 350.1 0.070 J 0.17 0.11 0.19 0.22 0.21 (D) 

TOTAL SOLIDS: 

T SS 160.2 NA 17.2 7.2 16.4 21.6 23.2 (D) 

T DS 160.1 806 773 800 712 575 574 (D) 

T OC 9060 5.6 5.2 5.3 5 7.6 7.7 (D) 

ALKALINITY, TOTAL: 

AS CaCO3 310.1 158 178 160 153 180 179 (D) 

ALKALINIT Y, BICARB 

AS CAC03 310.1 158 178 160 153 180 179 (D) 

ORP (mV) 94 108 80 82 72 72 

pH 6.5 5.4 6.7 6.3 6.2 6.2 

CONDUCT IVIT Y (μS) NA NA NA NA NA NA 

T EMPERAT URE (degrees C) 5.1 3.2 5.0 6.0 7.0 7.0 

-- = Not applicable NA = Not analyzed
 

μS = MicroSiemens ND = Not detected
 

mg/l = Milligrams per liter
 

mV = Millivolts
 

86 
--

--

--

--

Table A-3 (continued). Upflow Effluent Results 

UPFLOW EFFLUENT
 

W EU052897 W EU062397 W EU082897 W EU093097 W EU102997 W EU112597 

ANALYTIC AL 05/28/97 06/23/97 8/28/1997 9/30/1997 10/29/1997 11/25/1997 

ANALYTE METHO D m g/L mg/L mg/L mg/L mg/L mg/L 

AQ UEO US ALUMINUM 6010 ND ND 0.10 0.078 ND ND 

ARSENIC 6020 NA NA NA NA NA NA 

CADMIUM 6020 0.2 ND 0.0063 0.0040 0.010 0.016 

CALCIUM 6010 99.6 113 153 152 144 138 

IRON 6010 3.3 1.2 4.0 2.9 1.2 1 

LEAD 6020 NA NA NA NA NA NA 

MAGNESIUM 6010 48.9 53.7 64.6 64.8 65.6 56.6 

MANGANESE 6010 2.1 2.2 3.0 2.7 3.6 3.0 

NICKEL 6010 0.022 J ND 0.023 ND ND ND 

POT ASSIUM 6010 4.0 J 4.9 J 5.2 4.5 3.9 ND 

SILVER 6020 NA NA NA NA NA NA 

SODIUM 6010 14.8 0.94 J 6.9 13.5 14.7 15.0 

ZINC 6010 60.1 25.4 21.2 14.8 26.4 24.6 

ANIONS: 

SULFAT E 300.0 250 275 308 311 484 460 

SULFIDE T OT AL 376.2 17 6.1 2.4 4.1 2.2 2.4 

FLUORIDE 340.2 NA NA NA NA NA NA 

CHLORIDE 300.0 6.9 9.2 12.9 15.5 16.7 17.8 

PHOSPHORUS, T OT AL 365.3 NA NA NA NA NA NA 

ORT HOPHOSPHAT E 365.3 1.1 1.9 0.70 2.7 1.1 1.9 

NIT RAT E PLUS NIT RIT E AS N 353.2 ND ND 0.034 ND ND 

NIT RIT E AS N 354.1 0.0051 J 0.0047J 0.0040 ND 0.0020J 0.0032J 

NIT RAT E AS N 353.2/354.1 NA NA NA NA NA NA 

AMMONIA 350.1 ND 0.4 1.7 1.3 0.64 1.0 

TOTAL SOLIDS: 

T SS 160.2 102 38 31.6 13.6 27.2 

T DS 160.1 566 683 808 865 892 887 

T OC 9060 5.3 16 29.7 18.8 6.7 6.6 

ALKALINIT Y, T OT AL: 

AS CaCO3 310.1 190 228 NA 317 166 199 

ALKALINIT Y, BICARB 

AS CAC03 310.1 190 228 NA 317 166 199 

ORP (mV) -58 47 30 -37 NA 49 

pH 6.4 6.8 5.7 6.2 6.7 6.7 

CONDUCT IVIT Y (μS) NA NA NA NA NA NA 

T EMPERAT URE (degrees C) 9.2 12.7 12.0 10.3 5.7 5.5 

-- = Not applicable NA = Not analyzed
 

μS = MicroSiemens ND = Not detected
 

mg/L = Milligrams per liter
 

mV = Millivolts
 

87 
Table A-4. Substrate Results - Downflow Cell 

SUBSTRATE - DOWNFLOW CELL
 

SD2032394 SD2062994 SD5062994 SD5082594 

ANALYTICAL 03/23/94 06/29/94 06/29/94 08/25/94 

ANALYTE METHOD mg/kg mg/kg mg/kg mg/kg 

SEDIMENT ALUMINUM 6010 1410.0 65.6 423.0 2580.0 

ARSENIC 6020 2.9 0.14 ND 0.59 

CADMIUM 6020 2.2 0.56 4.8 5.1 

CALCIUM 6010 7040.0 406 2330.0 7650.0 

IRON 6010 2250.0 88.7 653.0 3650.0 

LEAD 6020 7.4 3.1 53.4 16.2 

MAGNESIUM 6010 2140.0 145 571.0 2120.0 

MANGANESE 6010 99.2 4.1 36.0 140.0 

NICKEL 6010 3.9 ND 1.9 4.9 

POTASSIUM 6010 890.0 149.0 184.0 1360.0 

SILVER 6020 0.061 0.024 0.79 0.16 

SODIUM 6010 ND 76.3 ND ND 

ZINC 6010 1560.0 59.7 1000.0 2650.0 

ANIONS: 

SULFATE 300.0 214 56.5 143.0 214 

SULFIDE, REACTIVE EPA/OSW 0.40 19.1 18.6 3.2 

SULFIDE, ACID VOLATILE EPA (Draft) NA 226 178.0 ND 

FLUORIDE 340.2 NA NA NA NA 

CHLORIDE 300.0 NA NA NA NA 

PHOSPHORUS, TOTAL 365.3 NA NA NA NA 

ORTHOPHOSPHATE 365.3 25.8 63.4 30.5 18.8 

NITRATE PLUS NITRITE AS N 353.2 NA NA NA NA 

NITRITE AS N 354.1 NA NA NA NA 

NITRATE AS N 353.2/354.1 NA NA NA NA 

AMMONIA 350.1 NA NA NA NA 

WATER (%) ILMO1.1 82 62 70 75 

NA = Not analyzed 

ND = Not detected 

88 
Table A-4 (continued). Substrate Results - Downflow Cell 

SUBSTRATE - DOWNFLOW CELL
 


ANALYTE 

ANALYTICAL 

METHOD 

SD2100494 

10/04/94 

mg/kg 

SD5100494 

10/04/94 

mg/kg 

SD2110294 

11/02/94 

mg/kg 

SD2010495 

01/04/95 

mg/kg 

SEDIMENT ALUMINUM 

ARSENIC 

CADMIUM 

CALCIUM 

IRON 

LEAD 

MAGNESIUM 

MANGANESE 

NICKEL 

POTASSIUM 

SILVER 

SODIUM 

ZINC 

6010 

6020 

6020 

6010 

6010 

6020 

6010 

6010 

6010 

6010 

6020 

6010 

6010 

2640.0 

1.5 

4.6 

8460.0 

3410.0 

46.4 

2180.0 

160.0 

3.7 

930.0 

0.17 

ND 

1510.0 

3200.0 

0.97 

10.5 

4890.0 

4640.0 

30.8 

1800.0 

151.0 

6.4 

1410.0 

0.29 

108.0 

2850.0 

3200.0 

1.3 

4.3 

11700.0 

4860.0 

11.3 

2910.0 

232.0 

7.0 

1140.0 

0.069 

92.8 

3170.0 

2430.0 

1.5 

4.3 

8770.0 

3460.0 

18.2 

2190.0 

144.0 

4.9 

729.0 

0.28 

ND 

3250.0 

ANIONS: 

SULFATE 

SULFIDE, REACTIVE 

SULFIDE, ACID VOLATILE 

FLUORIDE 

CHLORIDE 

PHOSPHORUS, TOTAL 

ORTHOPHOSPHATE 

NITRATE PLUS NITRITE AS N 

NITRITE AS N 

NITRATE AS N 

AMMONIA 

WATER (%) 

300.0 

EPA/OSW 

EPA (Draft) 

340.2 

300.0 

365.3 

365.3 

353.2 

354.1 

353.2/354.1 

350.1 

ILM01.0 

86.8 

103.0 

190.0 

NA 

NA 

NA 

39.0 

NA 

NA 

NA 

NA 

62 

187.0 

79.3 

70.6 

NA 

NA 

NA 

3.3 

NA 

NA 

NA 

NA 

70 

159.0 

1.1 

171.0 

NA 

NA 

NA 

12.6 

NA 

NA 

NA 

NA 

NA 

184.0 

15.3 

117.0 

NA 

NA 

NA 

6.4 

NA 

NA 

NA 

NA 

63 

NA = Not analyzed 

ND = Not detected 

89 
Table A-4 (continued). Substrate Results - Downflow Cell 

SUBSTRATE - DOWNFLOW CELL 

SD2061295 SD2082395 SD093097 

ANALYTICAL 06/12/95 34934 09/30/97 

ANALYTE METHOD mg/kg mg/kg mg/kg 

SEDIMENT ALUMINUM 6010 2050 1660 2200 

ARSENIC 6020 0.59 0.75 NA 

CADMIUM 6020 11.3 31.4 219 

CALCIUM 6010 7860 4720 7680 

IRON 6010 3200 2490 4400 

LEAD 6020 21.4 177 NA 

MAGNESIUM 6010 1860 1360 2070 

MANGANESE 6010 149 108 1950 

NICKEL 6010 7.0 6.2 22.5 

POTASSIUM 6010 646 463 666 

SILVER 6020 0.11 ND NA 

SODIUM 6010 119 ND 1930 

ZINC 6010 4990 4680 37500 

ANIONS: 

SULFATE 300.0 93.0 154 154 

SULFIDE, REACTIVE EPA/OSW 5.3 2.5 NA 

SULFIDE, ACID VOLATILE EPA (Draft) 528 687 187 

FLUORIDE 340.2 MNA NA NA 

CHLORIDE 300.0 NA NA NA 

PHOSPHORUS, TOTAL 365.3 NA NA NA 

ORTHOPHOSPHATE 365.3 5.0 1.8 NA 

NITRATE PLUS NITRITE AS N 353.2 NA NA NA 

NITRITE AS N 354.1 NA NA NA 

NITRATE AS N 353.2/354.1 NA NA NA 

AMMONIA 350.1 NA NA NA 

WATER (%) ILM01.0 60 64 

NA = Not analyzed 

ND = Not detected 

90 
Appendix B
 

Case Study
 

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