vvEPA
          United States
          Environmental Protection
          Agency
           Office of Research and
           Development
           Washington DC 20460
EPA/540/R-98/501
September 1998
www.epa.gov/ORD/SITE
EnviroMetal Technologies,
Inc., Metal-Enhanced
Dechlorination of Volatile
Organic Compounds
Using an  In-Situ Reactive
Iron Wall

Innovative Technology
Evaluation Report
               SUPERFUND INNOVATIVE
               TECHNOLOGY EVALUATION

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                                 EPA/540/R-98/501
                                  September 1998
  EnviroMetal Technologies, Inc.


Metal-Enhanced Dechlorination of
   Volatile Organic Compounds
Using an In-Situ Reactive Iron Wall


  Innovative Technology Evaluation Report
           National Risk Management Research Laboratory
             Office of Research and Development
             U.S. Environmental Protection Agency
                Cincinnati, Ohio 45268
                                Printed on Recycled Paper

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                                                 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. (formerly PRC Environmental Management, 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.

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                                                 Foreword
The U. S. Environmental Protection Agency (EPA) 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 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 manage-
ment 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 groundwater; 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.
                                                        E. Timothy Oppelt, Director
                                                        National Risk Management Research Laboratory

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                                                 Abstract
EnviroMetal Technologies, Inc. (EH), of Guelph, Ontario, Canada has commercialized a metal-enhanced dechlorination
technology that the University of Waterloo, Canada developed to treat aqueous media contaminated with chlorinated volatile
organic compounds (VOCs). The technology employs an electrochemical process that involves the oxidation of a reactive,
granular iron medium to induce reductive dechlorination of chlorinated VOCs.

The Supcrfund Innovative Technology Evaluation (SITE) Program evaluated an in-situ application of the technology during a
6-month demonstration at a confidential site in central New York in 1995. For the demonstration of the in-situ system, the
technology was constructed as a subsurface, reactive iron wall that fully penetrated a shallow sand and gravel aquifer. The top
of the wall was above the highest average seasonal groundwater level, about 3 feet below grade, and was covered with a layer
of native topsoil. The wall extended downward from (he top of the saturated zone and was situated on top of an underlying,
confining  clay layer.  The reactive iron wall, referred to as the "gate," was oriented perpendicular to the groundwater flow
direction and was flanked by impermeable sheet piling wings which also fully penetrated the aquifer. The sheet piling formed
a "funnel," creating a hydraulic barrier that diverted groundwater flow from a 24-foot-wide upgradient area through the gate,
and prevented untreated groundwater from flowing around the gate and mixing with treated groundwater on the downgradient
side.

During the demonstration, SITE Program personnel collected independent data to evaluate the technology's performance with
respect to  primary and secondary objectives.   Groundwater samples were collected at locations on the upgradient (influent)
and downgradient (effluent) sides of the iron, and also from locations within the iron. The groundwater samples were analyzed
for  VOCs  to evaluate the technology's ability to reduce chlorinated VOC  concentrations to applicable regulatory levels.  The
efficiency  with which the system removed certain chlorinated VOCs was evaluated.  Other data were collected to provide
information about the dechlorination process, as well as costs and operating and maintenance requirements for the system.

The results of the sample analyses indicated that the technology significantly reduced the concentrations of chlorinated VOCs
in groundwater passing through  the gate. These chlorinated VOCs included trichloroethene (TCE), cis-l,2-dichloroethene
(cDCE), and vinyl chloride (VC). All average critical parameter effluent concentrations, and 86 out of 90 individual critical
parameter  measurements, achieved the applicable U.S. Environmental Protection Agency (EPA) maximum contaminant levels
or New  York State Department of Environmental  Conservation target standards.  Removal efficiencies for TCE, cDCE, and
VC were consistently greater than 90 percent.  The results indicated no  decrease in removal efficiency or other significant
changes in system performance over the 6-month demonstration period.

EPA SITE Program personnel prepared this Innovative Technology Evaluation Report (ITER) to  present the results of the
SITE Program demonstration. The ITER evaluates the ability of the in-situ application of the metal-enhanced dechlorination
technology to treat chlorinated VOCs in contaminated groundwater based on the demonstration results.  Specifically, this
report discusses performance and economic data collected by SITE Program personnel, and also presents case studies and
additional  information about the technology provided by ETI.
                                                       IV

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                                        Contents
List of Figures	vm
List of Tables	x
Acronyms, Abbreviations, and Symbols	.	xi
Conversion Factors	xiv
Acknowledgments	xv
Executive Summary	1
1   Introduction	6
    1.1  Description of the SITE Program and Reports	6
        1.1.1    Purpose, History, and Goals of the SITE Program	6
        1.1.2    Documentation of SITE Demonstration Results	7
    1.2 Background of the Metal-Enhanced Dechlorination Technology in the SITE Program	 8
    1.3 Technology Description	8
        1.3.1    Process Chemistry	8
        1.3.2    General Application and Design of Metal-Enhanced Process Systems	9
        1.3.3    Advantages and Innovative Features of the Metal-Enhanced Dechloronation Process.. 10
    1.4 Applicable Wastes	;	10
    1.5 Overview of In-Situ, Metal-Enhanced Dechlorination Technology SITE Demonstration	 12
        1.5.1    Site Background	r	- 12
        1.5.2    Technology Design	12
        1.5.3    Technology and Monitoring System Construction	12
        1.5.4    Treatment System Operation	16
        1.5.5    SITE Demonstration Objectives	16
        1.5.6    Demonstration Procedures	17
    1.6 Postdemonstration Activities	 18
    1.7 Key Contacts	18
2  Technology Effectiveness Analysis	20
    2.1 SITE Demonstration Results	20
        2.1.1    Objective P-l: Compliance with Applicable Effluent Target Levels	23
        2.1.2   Objective P-2: Critical Parameter Removal Efficiency	23
        2.1.3   Objective S-l: Critical Parameter Concentrations as a Function of
                Sampling Location (Distance)	25

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                                Contents (continued)
         2.1.4    Objective S-2: Noncritical VOCs, Metals, and Other Inorganic Parameters	29
         2.1.5    Objective S-3: Eh, DO, pH, Specific Conductivity, and Temperature	36
         2.1.6    Objective S-4: Biological Microorganism Growth	40
         2.1.7    Objective S-5: Operating and Design Parameters	40
     2.2  Additional Performance Data	43
         2.2.1    BordenSite	46
         2.2.2    California Semiconductor Facility	46
         2.2.3    Belfast, Northern Ireland Facility	46
 3   Technology Applications Analysis	47
     3.1 Factors Affecting Performance	47
         3.1.1   Feed Waste Characteristics	47
         3.1.2   Hydrogeologic Characteristics	48
         3.1.3   Operating Parameters	49
         3.1.4   Maintenance Requirements	50
     3.2  Site Characterstics and Support Requkements	51
         3.2.1    Site Access, Area, and Preparation Requirements	51
         3.2.2   Climate Requirements	51
         3.2.3    Utility and Supply Requirements	52
         3.2.4   Required Support Systems	52
         3.2.5    Personnel Requirements	52
    3.3 Material Handling Requirements	52
    3.4 Technology Limitations	53
    3.5 Potential Regulatory Requirements	54
        3.5.1    Comprehensive Environmental Response, Compensation, and Liability Act	54
        3.5.2    Resource Conservation and Recovery Act	56
        3.5.3    Clean Water Act	57
        3.5.4    Safe Drinking Water Act	57
        3.5.5    Clean Air Act	57
        3.5.6    Mixed Waste Regulations	58
        3.5.7    Occupational Safety and Health Administration	58
    3.6 State and Community Acceptance	58
4   Economic Analysis	59
    4.1  Factors Affecting Costs	62
    4.2 Assumptions Used in Performing the Economic Analysis	62
    4.3  Cost Categories	64
        4.3.1   Site Preparation Costs	64
                                              vi

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                              Contents  (continued)
4.3.2    Permitting and Regulatory Costs	66
4.3.3    Mobilization and Startup Costs	66
4.3.4    Capital Equipment Costs	66
4.3.5    Labor Costs	67
4.3.6    Supply Costs	67
        Utility Costs	67
        Effluent Treatment and Disposal Costs	•	68
4.3.9    Residual Waste Shipping and Handling Costs	
4.3.10  Analyutical Services Costs	•	
4.3.11  Equipment Maintenance Costs	•	
4.3.12  Site Demobilization Costs	
       4.3.7
       4.3.8
                                                                                        68
                                                                                        68
                                                                                        68
                                                                                        69
    4.4 Economic Analysis Summary	•	••	69
5   Technology Status and Implementation	•	•	7^
6   References	7"
Appendix
    A  Vendor's Claims for the Technology
    B  Case Studies
    C  Summary of Analytical Data from the Demonstration of the In-Situ Metal-Enhanced Dechlorination
       Process: June 1995-December 1995
                                              vii

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                                  Figures
 1-1     Site Demonstration Area Layout	  14
 1-2     Plan and Profile Views of Funnel and Gate	15
 2-1     Critical VOC Removal Efficiency Over Time	25
 2-2     Critical VOCs vs. Distance-June	26
 2-3     Critical VOCs vs. Distance-July	26
 2-4     Critical VOCs vs. Distance-August	27
 2-5     Critical VOCs vs. Distance-October	27
 2-6     Critical VOCs vs. Distance-November	        28
 2-7     Critical VOCs vs. Distance-December	28
 2-8     Summary of Calcium Data Over Time	31
 2-9     Summary of Magnesium Data Over Time	31
 2-10    Average Calcium and Magnesium Values vs. Distance	31
 2-11    Summary of Iron Data Over Time	32
 2-12    Summary of Manganese Data Over Time	32
 2-13   Average Iron and Manganese Values vs. Distance	32
 2-14   Summary of Barium Data Over Time	34
 2-15   Summary of Bicarbonate Alkalinity Data Over Time	34
 2-16   Average Bicarbonate Alkalinity and pH vs. Distance	34
 2-17   Summary of Sulfate Data Over Time	          35
 2-18    Summary of Total Nitrate/Nitrite Data Over Time	35
 2-19    Average Sulfate and Total Nitrate/Nitrite Values vs. Distance	35
 2-20    Summary of pH Data Over Time	37
 2-21    Average pH Values vs. Distance	37
 2-22    Summary of SpecificConductivity Data Over Time	38
 2-23    Average Specific Conductivity Values vs. Distance	38
2-24    Average Groundwater Temperature in Iron Wells vs. Time	39
2-25    Summary of Eh Data Over Time	39
2-26    Average Eh Values vs. Distance	39
                                     VIII

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                       Figures (continued)
2-27   Total Phospholipid Fatty Acids vs. Distance	41
2-28   Piezometric Elevations-December 1995	45
4-1    Distribution of Fixed Costs for Continuous Wall	71
4-2    Distribution of Annual Variable Costs for Continuous Wall	71
4-3    Distribution of Fixed Costs for Funnel and Gate System	72
4-4    Distribution of Annual Variable Costs for Funnel and Gate System	72
                                     IX

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                                         Tables
ES-l    Superfund Feasibility Study Evaluation Criteria for the
        Metal-Enhanced Dechloronation Technology	4
1-1     Correlation Between Superfund Feasibility Evaluation Criteria and ITER Sections	7
1-2     Comparison of Technologies for Treating Chlorinated VOCs in Water	11
1-3     System Design Criteria and Applicable Effluent Standards	  13
2-1     Demonstration Results with Respect to Objectives	21
2-2     Summary of Critical VOC Concentrations at Effluent Sampling Locations	22
2-3     Summary of Critical Parameter Removal Efficiency: July-December 1995	24
2-4     Summary of Operating and Design Parameters	42
2-5     Piezometric Data	44
3-1     Summary of Environmental Regulations	55
4-1     Estimated Costs Associated with the Metal-Enhanced Dechloronation Technology:
        Continuous Wall System	60
4-2     Estimated Costs Associated with the Metal-Enhanced Dechloronation Technology:
        Funnel and Gate System	61

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          Acronyms, Abbreviations, and Symbols
AEA
ARAR
BGS
CAA
CaC03
CERCLA
CFR
Cl
CO32
DCA
cDCE
CWA
1,2-DCE
DO
DOE
Eh
EPA
ETI
Fe
Fe(OH)2
Fe(OH)3
FeC03
ft
H+
H2(g)
HC0-
in
ITER
Atomic Energy Act
Applicable or Relevant and Appropriate Requirement
Below ground surface
Clean Air Act
Calcium carbonate
Comprehensive Environmental Response, Compensation, and Liability Act
Code of Federal Regulations
Chloride ion
Carbonate ion
1,1-Dichloroethane
cis-1,2-Dichloroethene
Clean Water Act
1,2-Dichloroethene (general; undifferentiated for cis- and trans- isomers)
Dissolved oxygen
Department of Energy
Oxidation-reduction potential
U.S. Environmental Protection Agency
EnviroMetal Technology, Inc.
Zero-valent iron
Ferrous iron
Ferric iron
Ferrous hydroxide
Ferric hydroxide
Ferrous carbonate or siderite
Feet
Gallons per day
Hydrogen ion
Hydrogen gas
Bicarbonate ion
Inch
Innovative Technology Evaluation Report
                                     XI

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  Acronyms, Abbreviations, and Symbols (continued)
LCL
LDR
m
MCL
MDL
mg/L
Mn02(s)
msl
NAPL
NESHAP
NOEL
NPDES
NRG
NRMRL
NSPS
NYSDEC
O&M
OH-
ORD
OSHA
OSWER
PCB
PCE
pcf
PLFA
POTW
ppbv
ppe
QAPP
QA/QC
RCRA
RE
SARA
SDWA
S&W
SITE
TCA
TCE
TCL
Lower confidence limit
Land disposal restrictions
Meter
Maximum contaminant level
Method detection limit
milligram per liter
Manganese dioxide (solid)
mean sea level
Nonaqueous-phase liquid
National Emission Standards for Hazardous Air Pollutants
Nonobservable Effect Level
National Pollutant Discharge Elimination System
Nuclear Regulatory Commission
National Risk Management Research Laboratory
New Source Performance Standard
New York State Department of Environmental Conservation
Operating and maintenance
Hydroxyl ion
U.S. EPA Office of Research and Development
Occupational Safety and Health Act
Office of Solid Waste and Emergency Response
Polychlorinated biphenyl
Tetrachloroethene
Pounds per cubic foot
Phospholipid fatty acid
Publicly  Owned Treatment Works
Parts per billion by volume
Personnel protective equipment
Quality assurance project plan
Quality assurance/quality control
Resource Conservation and Recovery Act
Removal efficiency
Superfund Amendments and Reauthorization Act
Safe Drinking Water Act
Stearns & Wheler, L.L.C.
Superfund Innovative Technology Evaluation
1,1,1 -Trichloroethane
Trichloroethene
Target compound list
                                    xii

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     Acronyms, Abbreviations, and Symbols (continued)
TCLP
tDCE
TER
TIC
TSCA
vc
voc
WQS
Toxicity characteristic leaching procedure
Trans-1,2-Dichloroethene
Technology evaluation report
Tentatively identified compound
Toxic Substances Control Act
Micrograms per liter
Vinyl chloride
Volatile organic compound
Water quality standards
                                  XIII

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                              Conversion Factors
                 To Convert From
                            To
                     Multiply By
Length
Area:
Volume:
inch
foot
mile
square foot
acre
gallon
cubic foot
centimeter
meter
kilometer
square meter
square meter
liter
cubic meter
2.54
0.305
1.61
0.0929
4,047
3.78
0.0283
Mass:
pound
kilogram
0.454
Energy:
kilowatt-hour
megajoule
3.60
Power:
kilowatt
horsepower
1.34
Temperature:           ("Fahrenheit - 32)           "Celsius
                                                 0.556
                                           XIV

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                                       Acknowledgments
This report was prepared for EPA's SITE Program by PRC Environmental Management, Inc. (PRC), a wholly owned
subsidiary of Terra Tech, Inc., under the direction and coordination of Dr. Chien T. Chen, U.S. Environmental Protection
Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program project manager in the National Risk Manage-
ment Research Laboratory (NRMRL), Edison, New Jersey. Contributors and reviewers for this report included Ms. Ann Kern,
Mr. Vince Gallardo and Mr. Thomas Holdsworth of EPA NRMRL, Cincinnati, Ohio.

Special acknowledgment is given to Mr. Robert Focht and Mr. John L. Vogan of EnviroMetal Technologies, Inc., Guelph,
Ontario, Canada; Ms.  Diane  Clark of Stearns & Wheler,  L.L.C.; the site owners; and the New York Department of
Environmental Conservation for their cooperation and support during the SITE Program demonstration and during the
development of this report.
                                                   xv

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                                      Executive Summary
EnviroMetal Technologies, Inc. (ETI), has commercialized
a metal-enhanced dechlorination technology originally
developed by  the University of Waterloo, Canada  to
dechlorinate chlorinated  volatile organic compounds
(VOCs) such  as chlorinated methanes,  ethanes, and
ethenes in aqueous media.  An in-situ application of the
technology was demonstrated under the U.S. Environmental
Protection  Agency's   (EPA)   Superfund  Innovative
Technology Evaluation (SITE) Program at a confidential
site  in central New York  state from  June through
December 1995.

The  purpose of this Innovative  Technology Evaluation
Report is to present information that will assist Superfund
decision-makers in evaluating this technology's suitability
for remediating a particular hazardous waste site.  The
report provides an introduction to the SITE Program and
the metal-enhanced dechlorination process and discusses
the demonstration objectives and activities (Section 1);
evaluates  the  technology's effectiveness  (Section 2);
analyzes key factors pertaining to application of this
technology (Section 3); analyzes the costs of using the
technology to  treat groundwater contaminated  with
chlorinated   VOCs (Section  4);  summarizes  the
technology's current status (Section 5); and presents a list
of references (Section 6). Vendor's claims and additional
performance data for the technology, and case studies of
other applications of the metal-enhanced dechlorination
technology are  included  in Appendices A and  B,
respectively.

This   executive  summary  briefly  summarizes the
information discussed in the ITER and evaluates the
technology with respect  to  the nine criteria used  in
Superfund feasibility studies.

Technology Description

ETI  claims  that the technology can treat  chlorinated
methanes, ethanes,  and ethenes over a wide range  of
concentrations.    The  metal-enhanced  dechlorination
technology involves  oxidation  of iron  and reductive
dechlorination of chlorinated VOCs in aqueous media. A
reactive, zero-valent, granular iron medium oxidizes and
thereby induces dechlorination of chlorinated VOCs,
yielding simple hydrocarbons and inorganic chlorides as
by-products. The technology can be installed in-situ as a
permeable treatment wall, or can be applied aboveground
in a reactor. For in-situ applications, a reactive iron wall is
constructed by excavating a trench and backfilling it with
the reactive  iron medium.   The  wall is  oriented
perpendicular   to  the  flow  path  of  groundwater
contaminated  with  chlorinated  VOCs.    For  some
applications, a "funnel and gate" configuration may  be
used. The "funnel" consists of a scalable joint sheet pile or
slurry wall that directs water to the iron wall, or "gate,"
and also  prevents untreated groundwater  from flowing
around the  gate.   The impermeable funnels  allow
containment and  treatment  of a contaminant plume
without constructing an iron wall across the plume's entire
width.

Overview of the Metal-Enhanced Dechlorination
Technology SITE Demonstration

The SITE demonstration of the in-situ, metal-enhanced
dechlorination  process  occurred  between June and
December 1995. An in-situ funnel and gate system was
used to treat groundwater in  a shallow, unconsolidated,
sand and gravel aquifer. The demonstration site  was a
field adjacent to an inactive  manufacturing facility in
central New York. Groundwater in the shallow aquifer
generally flows westward from the manufacturing facility
and across the demonstration site. Former manufacturing
operations  at the facility  included  metal plating and
finishing.    Chemicals  used in  the metal  finishing
operations  apparently  resulted   in   groundwater
contamination; past groundwater samples collected at the
facility  and at the demonstration  site   indicated the
presence of chlorinated VOCs in the aquifer. Chlorinated

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groundwater  include  trichloroethene  (TCE), cis-1,2-
dichloroethene (cDCE), and vinyl chloride (VC).

For the SITE Program demonstration, a pilot-scale metal-
enhanced dechlorination system was constructed in the
field bordering the downgradient side of the facility to treat
groundwater as it moved off site. The system consisted of
a 12-foot-widc in-situ reactive iron wall (the gate) oriented
perpendicular to the groundwater flow direction. The iron
wall was about 3-feet thick, and fully penetrated the sand
and gravel aquifer.  The top of the wall was above the
average seasonal high groundwater level, about 3 feet
below ground surface, and was covered with a layer of
native topsoil. The wall extended down into an underlying,
confining clay layer. The wall was flanked by 15-foot-
long sections of impermeable sheet piling. These flanking
sections created the  funnel that directed flow toward the
gate and prevented untreated groundwater from bypassing
the reactive iron wall and mixing with treated water  in the
demonstration study area. According to ETI, the system
captured about a 24-foot-wide portion of the contaminant
plume.

The primary objectives of the SITE demonstration were as
follows:

  •    Determine whether treated groundwater from the
       in-situ, permeable treatment wall meets NYSDEC
       groundwater standards and federal MCL effluent
       standards   for  the  critical  contaminants:
       tetrachloroethene    (PCE),   TCE,  1,1,1-
       trichloroethane  (TCA), cDCE,  trans-1,2-
       dichloroethene (tDCE), and VC

  •    Determine the removal efficiency (RE) of critical
       contaminants from groundwater

The secondary objectives of the demonstration were:

  •    Determine concentration gradients of critical con-
       taminants as groundwater passes through the in-
       situ treatment wall

  •    Examine total  metals, chloride, sulfate, nitrate,
       bicarbonate, and non-critical VOC concentrations
       in groundwater as it passes through the treatment
       wall

  •    Document geochemical conditions (specific con-
       ductance, oxidation/reduction potential (Eh), pH,
       dissolved oxygen, (DO), and temperature) in
       groundwater passing through the treatment wall

  •    Examine biological microorganism growth in the
       reactive iron medium and in upgradient and
       downgradient groundwater

       Document operating and design parameters (ini-
       tial weight, volume, and density of the reactive
       iron medium, groundwater flow velocity) of the
       in-situ,.permeable treatment wall

During the demonstration, groundwater  samples were
collected from monitoring wells upgradient from, in, and
downgradient from the reactive iron wall.  Groundwater
samples were collected and, analyzed for the six critical
VOCs during June, July, August, October, November, and
December  1995.   'Samples  were  also  collected and
analyzed for noncritical parameters to support secondary
objectives.     Field  measurements  of  groundwater
elevations, dissolved oxygen (DO), temperature, specific
conductance, pH, and oxidation-reduction potential (Eh)
were also performed.

Samples  indicated that influent  groundwater contained
TCE at concentrations ranging  from about 32  to 330
micrograms per liter (fig/L); cDCE at concentrations
ranging  from, about 98 to  550  ng/L;  and  VC at
concentrations ranging from about 5 to 79 Ug/L.   Lower
concentrations (less than  15 ug/L of TCA and  1,1-
dichloroethane (DCA) were also typically present.

Based on .SITE Program data and postdemonstration data
obtained  by ETI, the average groundwater flow velocity
through the iron was probably in the range of about 0.4 to
1 foot per day. Assuming the high (conservative) velocity,
the  treatment  system design allowed  for  a minimum
contact time between groundwater and the reactive iron
medium of about 3 days.  Based on the range of possible
groundwater flow velocities,, between 29,000 and 73,000
gallons of groundwater was treated between the time the
system was  constructed  (May  1995) and the  SITE
demonstration was completed (December 1995).

SITE Demonstration Results

The following items summarize the significant results of
the SITE demonstration:

  •    Average critical contaminant concentrations for the
       downgradient wells were all below the  target.

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Average critical contaminant concentrations for the
downgradient wells were all below the target
MCLs and NYSDEC standards.   Individual
downgradient concentrations of critical VOCs
were predominantly nondetect. Individual results
for cDCE sporadically exceeded the NYSDEC
criterion of 5 |ig/L; however, concentrations were
significantly reduced from influent concentrations.

Minimum overall average REs were high for all
critical parameters present at significant concen-
trations in the influent groundwater. RE was
greater than 99.0 percent for TCE,  98.6 percent
for cDCE, and greater than 96.0 percent for VC.
Actual removal efficiencies may have been higher,
but are unknown, because the REs were calculated
using the detection limit of 1  ug/L to represent
effluent values that were below detectable limits.

Although significant concentrations of multi-chlo-
rinated ethenes (such as TCE) were reduced by
the technology, there was no detectable increase
in dechlorination byproducts such as cDCE, tDCE,
or VC. Concentrations of all of these compounds
in the downgradient wells were lower than in
upgradient wells, and were nondetectable in most
cases. These  observations indicate that the reac-
tive iron wall dechlorinated the original com-
pounds and the byproducts.

The concentrations of metals such as calcium and
magnesium generally  decreased as  groundwater
moved through the iron wall, coinciding with an
increase in pH, suggesting precipitation of metal
compounds.

Bicarbonate alkalinity decreased as groundwater
flowed through the wall. This observation, com-
bined with the metals behavior and the changes in
geochemical parameters, also suggests that inor-
ganic compounds were precipitating in the reac-
tive iron.

Total PLEA analyses indicated that total microbial
activity in water in the reactive iron wall was not
significantly higher than in water in the natural
aquifer materials upgradient or downgradient from
the wall. This observation indicates that the pro-
cess is abiotic.
  •    No significant operating problems were noted dur-
       ing the SITE demonstration. According to ETI,
       the most significant potential long-term problem
       with respect to operation appears to be the loss of
       porosity or iron reactivity due to precipitates.
       However, although inorganic compounds appeared
       to be precipitating during the SITE demonstration,
       there was no noticeable  decrease in system per-
       formance over the 6-month demonstration.

  •    Interpretation of piezometric data collected dur-
       ing the demonstration was complicated by the ex-
       tremely low horizontal gradient and close spacing
       of the monitoring wells.  For this reason, the ac-
       tual flow velocity through the iron is unknown,
       but appears to have been in the range of about 0.4
       to 1 foot per day.

Economics

Using information obtained from the SITE demonstration,
ETI, and other sources, an economic analysis examined 12
cost categories for a scenario in which the metal-enhanced
dechlorination technology was applied at full scale to treat
contaminated groundwater at a Superfund site for  a 20-
year period.    The cost estimate assumed that the site
hydrogeology and the general types and concentrations of
chlorinated VOCs were the same as those encountered
during the New York demonstration.   Based on  these
assumptions, the total costs were estimated to be about
$18 per  1,000  gallons  of groundwater  treated  for  a
continuous wall, and $20 per 1,000 gallons treated for a
full-scale funnel and gate system. However, total cost and
cost per gallon for using this technology are highly site-
specific.  Also,  because  this  passive  technology
simultaneously  controls off-site contaminant  migration
and removes contaminants, it combines beneficial features
of containment systems and treatment systems.

Superfund Feasibility Study Evaluation Criteria
for  the   Metal-Enhanced   Dechlorination
Technology

Table ES-1 briefly discusses an  evaluation of the in-situ
metal-enhanced dechlorination technology with respect to
the nine evaluation criteria used for Superfund feasibility-
studies   when  considering  remedial  alternatives  at
Superfund sites (EPA 1988c).

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Table ES-1. Superfund Feasibility Study Evaluation Criteria for the Metal-Enhanced Dechlorination Technology
                Criterion
                    Discussion
      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 Through
      Treatment
•  The technology is expected to protect human health and
   the environment by treating water to significantly lower
   concentrations of chlorinated VOCs.
•  Protection of the environment at and beyond the point of
   discharge should be evaluated based on uses of the
   receiving water body, concentrations of residual
   contaminants and treatment by-products, and dilution
   factors.
•  The technology's ability to comply with existing federal,
   state, or local ARARs (for example, MCLs) should be
   determined on a site-specific basis.
•  The technology was able to meet target effluent
   concentrations based on federal maximum contaminant
   levels (MCL) and New York State Department of
   Environmental Conservation (NYSDEC) groundwater
   discharge standards for average downgradient
   concentrations of all critical parameters.  After system
   performance stabilized, only four cDCE results out of 90
   individual critical parameter analyses slightly exceeded
   NYSDEC levels.
•  Human health risk can be reduced to acceptable levels
   by treating groundwater to site-specific cleanup levels;
   the time needed to achieve cleanup goals depends
   primarily on contaminant characteristics and groundwater
   flow velocity.
•  The long-term effectiveness  of the technology may
   depend on periodically replacing or treating the iron
   medium.
•  The treatment is permanent  because the technology
   dechlorinates chlorinated VOCs to less chlorinated
   compounds.
•  Periodic review of treatment system performance is
   needed because application of this technology to
   contaminated groundwater at hazardous waste sites is
   relatively recent.
•  Target compounds are dechlorinated to less toxic
   substances by the technology; also, the concentrations of
   individual target compounds and the total concentrations
   of chlorinated VOCs are reduced.

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Table ES-1. Superfund Feasibility Study Evaluation Criteria for the Metal-Enhanced Dechlorination Technology (continued)
             Criterion
            Discussion
    Short-Term Effectiveness
    Implementability
    Cost
    Community Acceptance
    State Acceptance
The technology appears to be able to reduce
chlorinated VOC concentrations as groundwater
passes through the system. However, the speed
of treatment is somewhat limited by the natural
groundwater flow velocity.
Appropriate hydrogeologic conditions should be
present and well-defined to implement this
technology!  Currently, the technology is most
easily implemented at shallow depths, and is best
suited for aquifers having an underlying aquitard at
less than 50 feet below ground surface.
The site must be accessible to typical construction
equipment and delivery vehicles.
The actual space requirements will depend on (1)
the length of iron wall required to capture a
contaminant plume, and (2) the thickness required
to allow sufficient residence time for
dechlorination.
Site-specific requirements may dictate the need for
additional services and supplies.
For a full-scale, 300-foot-long continuous iron wall
operating for 20 years to treat a plume under the
same general conditions observed at the New
York site, fixed costs are estimated to be
$466,600. Annual operating and maintenance
costs, including those for residual waste handling,
analytical services, labor, and equipment
maintenance, are estimated to be about $20,900.
This criterion is generally addressed in the record
of decision after community responses are
received during the public comment period.
However, because communities are not expected
to be exposed to harmful levels of VOCs, noise, or
fugitive emissions, community acceptance of the
technology is expected to be relatively high.
This criterion is generally addressed in the record
of decision; state acceptance of the technology will
likely depend on the long-term effectiveness of the
technology.	

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                                             Section 1
                                           Introduction
This  section  describes  the  Superfund  Innovative
Technology  Evaluation  (SITE)  Program   and  the
Innovative  Technology Evaluation  Report  (ITJtiR);
provides  background information on the EnviroMetal
Technologies, Inc. (ETI), metal-enhanced dechlorination
technology; identifies wastes to which this technology
may be applied; and provides a list of key contacts.  This
section also provides an overview of the SITE Program
demonstration of the in-situ metal-enhanced dechlorination
process.

1.1    Description of SITE Program and
       Reports

This section provides information about (1) the purpose,
history, and goals of the SITE Program, and (2) the reports
used to document SITE demonstration results.

1.1.1 Purpose, History, and Goals of the
       SITE Program

The primary purpose of the SITE Program is to advance
the development and demonstration, and thereby establish
the commercial  availability,  of innovative treatment
technologies applicable to Superfund and other hazardous
waste sites. The SITE Program was established by the
U.S. Environmental Protection Agency (EPA) Office of
Solid  Waste and Emergency Response (OSWER) and
Office of Research and Development (ORD) in response
to the Superfund Amendments and Reauthorization Act of
1986  (SARA), which  recognized  the need for an
alternative or innovative treatment technology research
and demonstration program.   The  SITE Program is
administered by  ORD's  National  Risk Management
Research Laboratory.   The overall  goal of the SITE
Program is to carry out a program of research, evaluation,
testing, development, and demonstration of alternative or
innovative treatment technologies that may be used in
response actions to achieve more permanent protection of
human health and welfare and the environment.

The SITE Program consists of four component programs:
(1) the  Demonstration  Program,  (2) the  Emerging
Technology Program, (3) the Monitoring and Measurement
Technologies Program, and (4) the Technology Transfer
Program.  This ITER  was prepared under the SITE
Demonstration  Program.    The  objective  of  the
Demonstration Program is to provide reliable performance
and cost data on innovative technologies so that potential
users  can  assess a  given  technology's suitability for
specific site cleanups. To produce useful and reliable data,
demonstrations are conducted at hazardous waste sites or
under conditions that closely simulate actual waste site
conditions.

Information collected during a demonstration is used to
assess the performance  of the technology, the potential
need for pretreatment and posttreatment processing of the
waste, the types of wastes and media that may be treated by
the technology, potential  operating  problems,  and
approximate capital and operating costs. Demonstration
information can also provide insight into a technology's
long-term operating and maintenance (O&M) costs and
long-term application risks.

Each  SITE  demonstration  evaluates  a  technology's
performance in  treating  waste  at  a  particular site.
Successful demonstration of a technology at one site or on
a particular waste does not ensure its success at other sites
or for other wastes. Data obtained from the demonstration
may require extrapolation to estimate a range of operating
conditions   over  which   the   technology   performs
satisfactorily. Also, any extrapolation of demonstration
data  should  be based  on other  information about the
technology,  such as information available from case
studies.

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 Implementation of the SITE Program is a significant,
 ongoing effort involving ORD, OSWER, various EPA
 regions,  and  private  business  concerns,  including
 technology developers and parties responsible for site
 remediation.  The technology selection process and the
 Demonstration Program together provide objective and
 carefully controlled testing of field-ready technologies.
 Innovative technologies chosen for a SITE demonstration
 must be pilot-  or full-scale applications  and must offer
 some  advantage  over  existing technologies;  mobile
 technologies  are of particular interest.

 1.1.2 Documentation of SITE
        Demonstration Results

 The results of each SITE demonstration are reported in an
 ITER and a  Technology Evaluation Report  (TER).
 Information presented in the ITER is intended tp assist
 Superfund decision makers evaluating specific technologies
 for  a particular cleanup situation.  The in-situ metal-
 enhanced dechlorination  technology has  been evaluated
 against  the  nine  criteria used for feasibility  studies
 supporting the Superfund remedial process.  The nine
 criteria are listed in Table 1-1 along with the sections of the
.ITER where information related  to each criterion is
 discussed. The ITER represents a critical step in the
development  and  commercialization  of a  treatment
technology.  The report discusses the effectiveness and
applicability  of the technology  and  analyzes  costs
associated  with its  application.    The  technology's
effectiveness is evaluated based on data collected during
the SITE demonstration and from other case studies. The
applicability of the technology is discussed in terms of
waste  and  site  characteristics  which  could  affect
technology performance, material handling requirements,
technology limitations,  and  other  factors  for  any
application of the technology.

The purpose of the TER is to consolidate all information
and records acquired during the demonstration. It contains
both  a  narrative  portion  and  tables  and graphs
summarizing  data.   The  narrative  portion  includes
discussions of  predemoristration, demonstration,  and
postdemonstration activities  as well as any deviations
from the demonstration quality assurance project  plan
(QAPP) during these activities and their impact. The data
tables  and graphs  summarize demonstration results
relative to project objectives. The tables also summarize
quality assurance and quality control (QA/QC) data and
data quality objectives. The TER is not formally published
by EPA. Instead, a copy is retained as a reference by the
EPA project manager for responding to public inquiries
and for recordkeeping purposes.                   :
 Table 1-1. Correlation Between Superfund Feasibility Evaluation Criteria and ITER Sections
             Evaluation Criterion3
              ITER Section
             Overall protection of human health and the
             environment
             Compliance with ARARs
             Long-term effectiveness and permanence
             Reduction of toxicity, mobility, or volume through
             treatment
             Short-term effectiveness
             Implementability
             Cost       '',..'.'
             State acceptance
             Community acceptance	•
              2.1.1,2.2.2,3.5,3.6

              2.1.1; 3.5; 3.6

              2.1.1; 2.1.2; 2.1,4; 2.2; 3.1
              2.2.1; 2.2.2; 2.2.3

              2.2.1; 2.2.2; 2.2
              1,6; 3.0; 5.0
              4.0
              2.1.1; 3.5; 3.6

             ••2:1.1'; 3.5;-3:6
            Note:  a Source: EPA 1988c

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 1.2    Background of the Metal-
        Enhanced Dechlorination
        Technology in the SITE Program

 In 1993, the owner of the New York demonstration site and
 its  consultant,  Steams &  Wheler, L.L.C.  (S&W),
 responded to a  solicitation from the SITE Program by
 submitting a proposal for the SITE Program to evaluate the
 metal-enhanced dechlorination process at the New York
 site.  Through  negotiations with the New York State
 Department of Environmental Conservation (NYSDEC)
 and ETI, the site owners and S&W proposed constructing
 a pilot-scale, in-situ  treatment system employing the
 metal-enhanced dechlorination process. The pilot-scale
 system  would  be  used to evaluate  the technology's
 suitability to remediate a  chlorinated VOC plume in
 groundwater  at the  site.   SITE Program personnel
 participated  in  the evaluation of the technology  by
 collecting  independent  data  to  evaluate  system
 performance.

 1.3    Technology Description

This section describes the principles of metal-enhanced
 dechlorination,  the  treatment  system  used  for  the
 technology, and  advantages and innovative features of the
 technology.

 1.3.1  Process Chemistry

The metal-enhanced dechlorination technology employs
an electrochemical process involving oxidation of iron and
reductive dechlorination of VOCs in aqueous media.
Although aluminum,  copper, brass, standard steel,  and
zinc have  also been  shown  to promote reductive
dechlorination of VOCs, zero-valent kon has been chosen
 for use in large-scale applications of the technology. Iron
is readily available, relatively inexpensive, and induces
rapid dechlorination of organic compounds (O'Hannesin
and Gillham 1992).

The technology induces conditions that cause substitution
of chlorine atoms by hydrogen.
Because chlorinated aliphatic VOCs are in a relatively
oxidized state, their reduction in the presence of reduced
metals is thermodynamically favorable. The corrosion of
zero-valent iron  (Feฐ) in contact with groundwater creates
a highly reducing environment in solution, evidenced by a
decline in oxidation/reduction potential (Eh). During the
process the solution pH increases, the concentration of
OH" increases, and electrons are transferred from the metal
to the  chlorinated organic compound.   Overall, the
reactions cause hydrogen ions to replace the chlorine
atom(s) of the chlorinated organic compound (Gillham
1996; Focht, Vogan and O'Hannesin 1996).

The reaction mechanism is not completely understood;
several mechanisms have been proposed. According to
Gillham and O' Hannesin (1994) the following equations
may describe the reactions that take place in the presence
of water, zero-valent  iron (Feฐ),  and a chlorinated
hydrocarbon (RC1):
                                        d-la)
                                        (1-lb)
                                        (1-lc)
                                        (1-ld)
       2Feฐ
       3H2O -* 3H+ + 3OH-
       2H++2e-->H2(g)
       RC1 + H+ + 2e- -* RH + Cl"
  In this series of equations, the conversion of Feฐ to
ferrous kon (Fe2*), commonly  known  as corrosion, is
described by Equation 1-la. Equation 1-lb describes the
ionization of water.   The  electrons  released by  the
corrosion of iron (Equation 1-la) react with hydrogen ions
(H+) and R-C1 according to Equations 1-lc and 1-ld,
resulting in the formation of Fe2*, hydroxyl ions (OHO,
hydrogen gas [H^g)], nonchlorinated hydrocarbons (RH),
and chloride ions (Cl~).  While the ionization of water
(equation 1-lb) accompanies the dechlorination process, it
is unknown if this reaction  is required for the overall
dechlorination reaction to occur (Gillham and O'Hannesin
1994; Gilham 1996).

For multi-chlorinated VOCs such as tetrachloroethene
(PCE), trichloroethene (TCE), or 1 ,2-dichloroethene (1,2-
DCE), the progression of the dechlorination reaction is not
completely  understood.  Chen (1995) proposed that the
dechlorination of a multi-chlorinated VOC (in this case
PCE) may follow a sequential mechanism, evidenced by
the appearance of intermediate by-products such as TCE,
1,2-DCE, and vinyl chloride  (VC), as shown  in  the
following equations:
Feฐ -*• Fe2+ + 2e-
Hp - H+ + OH'
C12C=CC12 + H+ + 2e- - C1CH=CC12 + Cl"
C1CH=CC12 + H+ + 2e- - C1CH=CHC1 + Cl'
C1CH=CHC1 + H+ + 2e- - CH2=CHC1 + Cl'
CH2=CHC1 + H+ + 2e- - CH2=CH2 + Cl'
                                          (l-2b)

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Others have proposed alternate  reaction mechanisms.
According to EH, recent research has indicated that the
dechlorination  of PCE and TCE may involve multiple
mechanisms.   Focht,  Vogan, and  O'Hannesin  (1996)
report that for bench-scale studies involving dechlorination
of TCE, only about 10 to 20 percent of the original mass of
TCE typically appears as 1,2-DCE, and less than 1 percent
appears as vinyl chloride (VC).  Based on similar mass
balance estimates, some researchers have suggested that
the predominant dechlorination reaction mechanism may
not be sequential, and may be due to a precipitous transfer
of electrons from the iron  to the organic contaminant
molecule through direct contact (Gillham and O'Hannesin
1994; Gillham 1996). However, 1,2-DCE and VC are also
dechlorinated by reactive iron, and it is possible that these
compounds are generated and destroyed too  rapidly to
allow detection of the full amounts generated.

For long-term remediation projects using this technology,
decision  makers and  technology designers should  be
aware of the possibility of formation of by-products, such
as 1,2-DCE and VC if multi-chlorinated compounds such
as TCE or PCE are incompletely dechlorinated. However,
this effect was not observed during the New York
demonstration.    The  results   of  the New  York
demonstration indicated that significant decreases in TCE,
cDCE,  and  VC  occurred  as  groundwater  moved
throughout the reactive iron. No  measurable increase in
the amounts of expected  dechlorination  by-products
(cDCE and VC) was observed; effluent concentrations of
cDCE and VC were significantly less than influent levels
during all months of testing (see Section 2.1.1).

Past research by ETI and others has also suggested that
when  the process is used to  dechlorinate  VOCs  in
groundwater that also contains soluble metal species, the
dechlorination reaction is accompanied by precipitation of
metal compounds from the groundwater.  If no oxygen is
present  and  pH becomes  sufficiently  high,  ferrous
hydroxide [Fe(OH)2] may precipitate:
      + + 20H--Fe(OH),(s)
(1-3)
Carbonate (CO320 may react with Fe2* to form ferrous
carbonate (FeCO3), known as siderite:
         CO32--FeCO3(s)
(1-4)
 Because iron-hydroxide and iron-carbonate precipitates
 are  formed  during  treatment, the  concentrations  of
dissolved iron in the effluent are expected to be relatively
low.  Depending on  concentrations of soluble metal
compounds in influent groundwater, other carbonates
such as calcium carbonate, may precipitate (Gillham
1996; Reardon 1995).

1.3.2 General Application and Design of
       Metal-Enhanced Dechlorination
       Process Systems

The metal-enhanced  dechlorination process  uses  a
reactive, zero-valent, granular iron medium to perform in-
situ  remediation  of groundwater contaminated with
chlorinated VOCs. Chlorinated VOCs are among the most
pervasive groundwater contaminants  at Superfund and
other hazardous waste sites.

The technology  is typically installed as a permeable
subsurface wall; the dechlorination reaction described in
Section 1.3.1  occurs as groundwater flows through the
wall.   For  this reason,  optimal site  conditions for
application of this technology include shallow depth  to
groundwater and the presence of a confining layer beneath
the contaminated aquifer.   Also, installation of in-situ
systems  may  require  excavation to the  underlying
confining layer, and therefore the thickness and depth to
the bottom of the saturated zone are determining factors
for application of this technology.

The technology may be installed as a continuous, reactive
subsurface wall,  or as a configuration of  alternating
"funnels" and "gates". For funnel and gate configurations,
impermeable  sections  of scalable joint sheet piling  or
slurry walls contain the contaminant plume and funnel
groundwater flow through the iron wall or gate.  The
number and dimensions of the gates required depends on
the size of the contaminant plume  and hydrogeologic
factors such as  gradient,  flow  velocity, and saturated
thickness.

The metal-enhanced dechlorination process may also be
installed   in   an  aboveground  reactor,  supporting
conventional pump-and-treat operations.   Aboveground
reactors may be particularly suited to short-term, small-
scale remediation  projects  requiring  treatment  of
relatively  small  amounts  of groundwater, or for sites
where  excavation  and  construction activities  in  the
immediate vicinity   of   a contaminant  plume  are
impractical.  For aboveground applications, groundwater
is extracted from the aquifer and pumped to the reactor for

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 treatment.  The SITE Program evaluated a pilot-scale
 aboveground reactor at a site in New Jersey in 1994 and
 1995.    (The  results   of  the  aboveground  reactor
 demonstration were reported in a previous 1'i'HR (EPA
 1997).

 The in-situ  system  design  used during  the SITE
 demonstration was a subsurface treatment cell consisting
 of one reactive iron wall flanked by two  impermeable
 sheet piling sections, as shown in Figure 1-1. The funnel
 and gate system used was not designed to capture and treat
 the entire chlorinated VOC plume present in groundwater
 at  the site,  but  rather  to  evaluate the  technology's
 effectiveness at pilot scale. Pilot scale systems allow for
 measurement, control, modification, and optimization of
 design and operating parameters before construction of the
 full scale system. The system may eventually be expanded
 or replaced by a full scale system consisting of several
 alternating  funnel and gate sections or a continuous iron
 wall to capture and treat the entire plume (ETI 1996d).

 1.3.3 Advantages and Innovative
       Features of the Metal-Enhanced
       Dechlorination Process

Table  1-2  compares   the  in-situ  metal-enhanced
dechlorination technology to  several other treatment
options for water contaminated with chlorinated VOCs.
Common ex-situ  methods  for treating  groundwater
contaminated with solvents and other organic compounds
include air  stripping, steam stripping, carbon adsorption,
biological treatment, chemical oxidation, and photolysis.
The metal-enhanced dechlorination technology offers a
major advantage over some of these more  conventional
treatment technologies  because the process destroys
hazardous substances rather than transferring them to
another medium, such as activated carbon or air.

The technology can treat groundwater with relatively high
concentrations of chlorinated VOCs.  For example, as
indicated by the  case  studies in Appendix  B,  the
technology has been used to treat groundwater containing
chlorinated VOCs at concentrations up to about 300,000
ug/L. The contaminant loading mass and rate, relative to
the available iron surface area in  the system,  affects
system performance (see Section 3.1); higher contaminant
concentrations may increase the amount of iron required to
completely dechlorinate a substance and all associated
dechlorination by-products. However, the reactive iron is
 a by-product of metal machining and finishing operations,
 and is therefore readily-available and relatively inexpensive
 (Gillham 1995; ETI 1996d).

 A  significant  advantage   of  the  metal-enhanced
 dechlorination process over conventional pump- and-treat
 technologies is  that it can treat  groundwater in-situ,
 eliminating the need to extract contaminated groundwater
 before treatment. In-situ systems also eliminate the need
 to manage treated effluent that can lead to relatively high
 costs for conventional, ex-situ technologies. Also, in-situ
 systems eliminate the need for intrusive surface structures,
 allowing less restricted long-term use of the area where the
 system is installed.

 Once  installed,  operating  requirements  are minimal.
 Because the technology is a passive treatment  process
 there are no moving parts and no utilities are required. The
 system is installed below ground,  and therefore is not
 subject to the effects of adverse weather conditions.

 Long-term (greater than 5 years) data for field applications
 of in-situ systems are unavailable at the time of this report;
 therefore, the useful life of the reactive iron under field
 conditions  is unknown.  Precipitates may reduce the
 porosity of the iron or block the available reactive surface
 area.    The results  of a  previous  SITE Program
 demonstration of the aboveground reactor indicated that a
 portion of the iron would periodically require mechanical
 mixing, treatment, or  replacement to  maintain target
 removal  efficiency levels (EPA 1997).  However, no
 decrease in the in-situ  system's performance  was
 detectable over the 6-month New York demonstration.

 1.4   Applicable Wastes

 According to ETI, existing performance data indicates that
 the metal-enhanced dechlorination process is applicable to
 a wide range of chlorinated methanes, ethanes, and
 ethenes in water  (Focht, Vogan, and O'Hannesin 1996).
 Research is currently underway at other sites to determine
 the technology's  ability to reduce concentrations of other
 types of substances such as hexavalent chromium (Puls,
Powell, and Paul  1995; ETI 1996c). At the New York site,
the SITE Program demonstration primarily examined the
technology's ability to treat six critical contaminants:
PCE,  TCE, cis-l,2-dichloroethene (cDCE), trans-1,2-
dichloroethene (tDCE),  1,1,1-trichloroethane (TCA); and
VC.
                                                    10

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Table 1-2.  Comparison of Technologies for Treating Chlorinated VOCs in Water
    Technology
Advantages
Disadvantages
    Air stripping
    Steam stripping
    Air stripping with carbon
    adsorption of vapors
    Carbon adsorption
    Biological treatment (ex-situ)
     Biological treatment (in-situ)
     Chemical oxidation (in-situ)
     Metal-enhanced
     dechlorination technology (in-
     situ)
Effective for high
concentrations; can treat a
wide range of VOCs;
mechanically simple;
relatively inexpensive

Effective for all
concentrations and many
types of VOCs

Effective for high
concentrations and many
types of VOCs
Low air emissions; effective
for high concentrations
Low air emissions; relatively
inexpensive
Relatively inexpensive; may
not require utilities; can be
constructed without obtrusive
surface structures

No air emissions; no
secondary waste; VOCs
destroyed; can be applied
without obtrusive surface
structures

Dechlorinates chlorinated
VOCs to less hazardous
substances; generates no air
emissions and no secondary
waste; no chemicals (such as
O3 or H2O2) required; minimal
maintenance required;
operates passively; no
utilities required; in-situ
systems can be constructed
without obtrusive surface
structures
Inefficient for low
concentrations; VOCs
discharged to air or require
secondary "polishing"
VOCs discharged to air or
require secondary "polishing";
high energy consumption

Sometimes inefficient for low
concentrations; requires
disposal or regeneration of
spent carbon; relatively
expensive

Sometimes inefficient for low
concentrations; requires
disposal or regeneration of
spent carbon; relatively
expensive

Inefficient for high
concentrations; slow rates of
removal; sludge treatment
and disposal required

Slow rate of treatment
May not be cost effective for
high contaminant
concentrations; requires
chemicals such as O3 or
H202.

Inability to treat some VOCs;
potential for gradual loss of
hydraulic conductivity and
reactivity of iron; potential for
formation of by-products;
construction requires
displacement and
management of potentially
contaminated subsurface
soils; geologic conditions may
preclude its use at some sites
                                                      11

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 1.5    Overview of the In-Situ, Metal-
        Enhanced Dechiorination
        Technology SITE Demonstration

 This   section   provides  an  overview  of  the  site,
 predemonstration and postdemonstration activities, and
 SITE Program demonstration objectives and procedures.

 1.5.1  Site Background

 The SITE Program demonstration of the in-situ metal-
 enhanced dechlorination process was conducted over a 6-
 month period from June through December 1995.  The
 demonstration took place at an inactive manufacturing
 facility in central New York state.  Former operations at
 the facility included  electroplating and metal finishing
 (Steams and Wheler [S&W] 1993).

 The site is  located  in  a river  valley and  overlies
 unconsolidated materials consisting of a clayey sand and
 gravel water-bearing  zone  overlying  a  dense clay
 confining layer. The top of the clay layer is about 13 to 16
 feet below  ground surface.  The depth to groundwater
 varies seasonally, but typically ranges from about 3 to 7
 feet below ground surface. The predominant groundwater
 flow direction on site is west (S&W 1993).

 Past site operations appear to have resulted in groundwater
 contamination in the sand and gravel aquifer. Groundwater
 samples indicated the presence of a chlorinated VOC
 plume, apparently related to the electroplating and metal
 finishing operations, in the west-central part of the site,
 that was migrating  off site to the west. Groundwater
 contaminants at the site reportedly include the chlorinated
 VOCs  TCE, cDCE, VC, TCA, and  1,1-dichloroethane
 (DCA); and other compounds (S&W 1993).

 Based on the types and concentrations of contaminants in
 groundwater, the hydrogeologic conditions, and the need
 to construct a remediation system that would not restrict
 property use, the metal-enhanced dechlorination process
 appeared suited for groundwater remediation at the New
 York site. The system would be used to passively treat
 groundwater flowing off site to the west, inhibiting off-site
 migration of chlorinated VOCs (S&W 1994).

 1.5.2 Technology Design

 In  1994, ETI conducted bench-scale  column tests using
contaminated groundwater from  the New York site.
 During these studies, ETI determined the apparent half-
 lives for chlorinated VOCs present in the site groundwater
 samples, and for the by-products that could potentially be
 generated by dechlorinating these VOCs.  The half-life
 data were evaluated to determine the required residence
 time in the reactive iron for complete dechlorination to
 occur.  The residence  time estimates, along with site
 hydrogeologic characteristics such as hydraulic gradient
 and flow velocity, determined the required thickness for
 the reactive iron wall (ETI 1994).

 ETI and S&W used the results of the bench-scale studies to
 custom-design a pilot-scale funnel and gate system.  The
 design  contaminant  concentrations  and  applicable
 regulatory target levels are shown in Table 1-3.  The
 design was based on the estimated residence time required
 to dechlorinate TCE, cDCE, VC, PCE, and TCA from the
 influent design concentrations to below the applicable
 regulatory standards shown on Table 1-3.  This time was
 estimated by ETI as about 56 hours.  The system  design
 allowed a minimum residence time of approximately 72
 hours for water in the reactive iron based on a predicted
 maximum groundwater flow velocity of about 1 foot per
 day through the iron. ETI estimated the groundwater flow
 velocity based on an assumed horizontal gradient of 0.002,
 and hydraulic conductivity and porosity values of 142 feet/
 day and 0.4, respectively, for the iron (ETI 1994).

 7.5.3  Technology and Monitoring
        System Construction

 The pilot-scale funnel and gate system was constructed in
 May 1995. The system was constructed in an agricultural
 field adjacent to the west side of the site. Figure 1-1  shows
 the treatment system area layout; Figure 1-2 shows the
 system configuration hi plan view and cross-section.

The system  was constructed by  driving sealable-joint
 sheet piling downward from the ground surface, through
 the sand and gravel, and about 1 foot into the underlying
clay layer located about 15 feet below ground surface. The
 sheet   piling  formed  a  rectangular  box-like  area
 approximately  12  feet by 6.5 feet in plan.  The long
dimension of  this "box" was  perpendicular to  the
groundwater flow direction. Fifteen-foot-wide sections of
sheet piling were also driven on each end of the box.  These
flanking sections of piling extended about 1 foot down into
the clay layer, creating  an impermeable  barrier to
groundwater flow (the funnel) on either end of the  box.
                                                  12

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Table 1-3. System Design Criteria and Applicable Effluent Standards
Contaminant
TCA
PCEb
TCE
cDCE
tDCE
VC
Design Influent NYSDEC Federal Maximum
Concentration8 Groundwater Contaminant Level
(ug/L) Standard (ug/L)
(M9/L)
96
90
529
5,650
__c
220
5
5
5
5
5
2
200
5
5
70
100
2
      Source: PRC 1995
      Notes:
             a     Determined by NYSDEC.
             b     Included as a design parameter and critical parameter for the demonstration;
                   however, PCE was not detected during the SITE demonstration.
             c     NYSDEC did not require specification of a design influent concentration for tDCE
                   as tDCE was not anticipated to be present at significant concentrations in the
             influent groundwater.
                                               13

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                                                                                                                                        P8
        Sheet
         Pile
       "Funnel"
      LEGEND
                                                                                          PS
                                                      Treatment
                                                        Cell
                                                                    P3
                                                                              PS
                                                                                              General
                                                                                            Groundwater
                                                                                           Flow Direction
P2
                                                                     PI
                                                                                          P4
       -t-
SITE Program
Monitoring Well

SITE Program
Piezometer
      r.V.V.'l Iron Wall
      tฑii^1 ("Gate")

             Pea Gravel
                                                                                                                                       P7
                                                                       0'
                                                                                     101
      SOURCE:  Modified from PR01995.
                                                                              APPROXIMATE SCALE: V =
Figure 1-1. SITE demonstration area layout

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                                                             General
                                                           Groundwater
                                                           Flow Direction
                 PLAN VIEW
       NOT TO SCALE
                                                    Well Screen
                                                                X   SITE Program
                                                                                        Protective
                                                                                         Catlngt
                                                                                                        Monitoring Wells:

                                                                                                    MW-D2       MW-Fป2      MW-U2
 Monitoring Well   E

| Aquifer Materials  |

Silt and clay topsoll i
 Iron Wall
 (Gate)

I Pea Gravel

7\   Clay
                                                                                                                               PROFILE VIEW
Figure 1-2. Plan and profile views of funnel and gate.

-------
 Soil in the area enclosed by the box was then excavated to
 the top of the clay layer. Soil from the saturated zone was
 placed in lined roll-off boxes and stored pending analysis
 and off-site disposal.  The box was then dewatered, and
 sheet piling was used to divide the box into three parallel
 compartments. The middle compartment, which was 3
 feet wide,  was backfilled  with reactive iron.   The
 compartments  on  the  east  (upgradient)  and   west
 (downgradient) sides  of the iron (each about 1.75 feet
 wide) were backfilled with pea gravel to minimize the
 effects of inconsistent flow caused by heterogeneity and
 anisotropy in the aquifer  materials, and to facilitate
 monitoring well construction. The pea gravel zones and
 the iron zone are collectively referred to as the "treatment
 system"  or  "cell" in  subsequent discussions.    To
 differentiate, when referred to specifically, the reactive
 iron zone is referred  to as the  "iron wall" throughout
 subsequent sections. The iron and pea gravel zones were
 filled to about 3 feet below grade, to allow for a seasonal
 high groundwater table.

 Three groundwater monitoring wells, consisting of PVC
 well screens with riser pipes attached, were constructed in
 each compartment.  The three monitoring wells in the
 upgradient pea gravel section were identified as MW-U1,
 MW-U2, and MW-U3.  The wells  in the  iron  were
 identified MW-Fel, MW-Fe2, and MW-Fe3; the wells in
 the downgradient pea gravel section were identified  as
 MW-D1, MW-D2, and MW-D3.

 After the monitoring  wells were in  place and as the
 compartments were backfilled, the sheet piling dividers
 between the compartments, as well as the sheet piling
 forming the long, outer walls of the box (the two sections
 perpendicular to the groundwater flow direction)  were
 removed. This allowed groundwater to enter the treatment
 cell, passing in turn through the upgradient pea gravel,
 reactive iron, and downgradient pea gravel, and then exit
 the cell and return to the natural aquifer materials. After
 the sheet piling dividers were removed, the upper 3-foot
 portion of the trench was backfilled to grade with native
 topsoil.

 In order to provide additional  information  regarding
 inorganic analyte concentrations  downgradient from the
 treatment system, three monitoring wells (MW-D4, D5,
and D6) were installed about 5 feet downgradient from the
treatment  system,  as  shown on Figure  1-1.   Eight
piezometers (P-l through P-8) were installed upgradient
from the treatment cell to evaluate the hydraulic gradient
 and groundwater flow velocity  in  the vicinity of the
 system.

 1.5.4 Treatment System Operation

 Flow through the cell commenced on May 18,1995. The
 in-situ system passively treated contaminated groundwater
 as it flowed through the  reactive iron.   No additional
 construction or O&M activities directly related to the
 metal-enhanced  dechlorination process were required.
 Based on data from upgradient monitoring wells MW-U1,
 U2  and  U3, the  influent groundwater  consistently
 contained TCE at concentrations ranging from 32 to 330
 micrograms per liter (ug/L); cDCE at concentrations
 ranging from  98 to 550 ug/L;  VC at concentrations
 ranging from about 5 to 79 ug/L; and low levels (2 to 12
 ug/L) of TCA. Trace levels (less than 5 ug/L) of 1,1-
 dichloroethane (DCA) and tDCE were also sporadically
 detected in the  influent  groundwater (see  Tables Cl
 through C6 in Appendix C).

 Piezometric data gathered  during the SITE demonstration
 were inconclusive due to the low horizontal flow gradient,
 but suggested that the groundwater flow velocity through
 the iron wall was in the range of about 0.4 to 1 foot per day
 (see  Section 2.1.7).   Based on these estimates, and an
 assumed average saturated thickness of  10  feet, the
 cumulative volume of groundwater treated between the
 time  of  construction (May 1995)  and  the  time the
 demonstration was completed (December 1995) was in the
 range of about 29,000 to 73,000 gallons.

 1.5.5 SITE Demonstration Objectives

 EPA  and  PRC  established primary and  secondary
 objectives for  the SITE  demonstration of  the metal-
 enhanced dechlorination process.  The objectives were
based on EPA's and PRC's understanding of the metal-
 enhanced  dechlorination  process,  SITE demonstration
program goals, and input from ETI. Primary objectives
 were  considered  to be  critical  for the   technology
evaluation, while secondary objectives involved collecting
additional data considered useful, but not critical, to the
process evaluation.  The demonstration objectives were
defined  in the EPA-approved QAPP dated  May 1995
(PRC 1995). (A copy of the QAPP accompanies the TER.)
                                                   16

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Primary Objectives

The  following were the primary (P) objectives of the
technology demonstration:

  •    PI- Determine whether treated groundwater from
       ETFs in-situ, permeable treatment wall meets
       NYSDEC groundwater standards and federal
       maximum contaminant level (MCL) standards for
       the critical contaminants: PCE, TCE, TCA, cDCE,
       tDCE,andVC.

  •    P2 - Determine the removal efficiency of critical
       contaminants from groundwater

Primary objective PI was established to directly evaluate
the metal-enhanced dechlorination process's ability to
destroy certain chlorinated VOCs present in groundwater
at the New York site, and was to be evaluated based on
VOC concentration data from downgradient wells MW-
Dl, D2, and D3. Primary objective P-2 was established to
provide a quantitative  criterion for evaluating  system
performance, and to provide a basis for comparing the
technology's performance with conventional remediation
technologies. Objective P-2 was to be based primarily on
comparison of upgradient (influent) samples from wells
MW-U1, U2, and U3 to downgradient (effluent) samples
from wells MW-D1, D2, and D3.

Secondary Objectives

The following were the secondary  (S) objectives of the
demonstration:

   •     SI- Determine concentration gradients of critical
        contaminants as groundwater passes through the
        in-situ treatment wall

   •     S2 - Examine total metals, chloride, sulfate, ni-
        trate, bicarbonate, and noncritical VOC concen-
        trations in groundwater as it passes through the
        treatment wall

   •     S3 - Document geochemical conditions in ground-
        water as groundwater passes through the treatment
        wall

   •     S4 - Examine biological microorganism growth
        in the reactive iron medium and in upgradient and
        downgradient groundwater
  •    S5 - Document operating and design parameters
       of the in-situ, permeable treatment wall


Secondary objective S1 was to be evaluated based oh data
from all nine wells in the treatment cell. Objectives S2and
S3 were to be evaluated by comparison of data from all
nine wells in the treatment cell (and the three downgradient
wells in the aquifer for some parameters), thus providing
data on the performance of the reactor, the dechlorination
reaction mechanism, and changes in treated groundwater
chemistry. Objective S4, which would also be evaluated
based  on data  from the 12  monitoring  wells,  was
established   to  demonstrate  that  the metal-enhanced
dechlorination process is abiotic, and also to evaluate the
potential  effect of bacterial growth on the reactive iron.
Objective S5 was established  to  provide  data  for
estimating costs associated with use of the in-situ metal-
enhanced dechlorination process, and was to be based on
observations  during  construction, demonstration data,
postdemonstration  data  (if  feasible),  and  data to be
provided by  S&W and ETI.  (Table 2-1 in Section  2
summarizes the  demonstration objectives and purposes
and the evaluation criteria for each objective, as well as key
demonstration findings with respect to each objective.)

1.5.6 Demonstration  Procedures

The SITE  Program  evaluated the  treatment system's
effectiveness over a period of about 6 months by collecting
independent data.  In general,  three types of data were
obtained: 1) analytical  data for  groundwater samples
collected from monitoring wells located in and adjacent to
the reactive iron wall; 2) construction and design data and
observations, such as bulk density of the iron and geologic
conditions;  and  3)  piezometric  data   from the  12
monitoring wells and eight piezometers.  Data collection
procedures for the demonstration  were specified in the
EPA-approved QAPP written specifically for the in-situ
metal-enhanced dechlorination  technology demonstration
(PRC 1995). Detailed discussions of the sample collection
techniques,  analytical methods, and  deviations from the
QAPP are  discussed in detail in the TER, which  is
available from the EPA project manager (see Section 1.7).

Prior  to the demonstration, SITE  Program  personnel
observed the construction  of the  treatment cell  and
collected samples of the reactive iron medium.  The SITE
team laboratory analyzed the iron samples to determine the
bulk density of the reactive iron medium.  SITE Program
                                                    17

-------
personnel  also  oversaw  the  installation  of  eight
piezometers (P-l, P-2, P-3, P-4, P-5, P-6, P-7, and P-8)
upgradient of the reactive cell  and three groundwater
monitoring wells downgradient from the cell (see Figure
1-1).

During  the demonstration,  SITE  Program  personnel
collected groundwater samples from the monitoring wells
in and downgradient from the treatment cell, as specified
by the QAPP. The first round of sampling was conducted
in June, about 2 weeks after installation of the treatment
cell and completion  of monitoring well development.
Subsequent sampling events occurred in July, August,
October, November, and December 1995.

During each sampling event, sample fractions for VOC,
bicarbonate alkalinity, chloride, sulfate, nitrite nitrogen,
and total nitrate/nitrite nitrogen analysis  were  collected
from the nine wells in the treatment cell.  SITE Program
personnel also collected groundwater sample fractions for
metals analysis from the nine wells in the cell and the three
downgradient wells located outside of the cell. Sample
fractions were collected from all 12 wells for phospholipid
fatty acid (PLFA)  analysis during June, October, and
December.    SITE Program personnel also  prepared
and submitted QA/QC samples as specified in the EPA-
approved QAPP (PRC 1995).   Samples were shipped to
off-site laboratories for analysis.

In addition to the water samples collected for laboratory
analyses, SITE Program  personnel collected samples for
field measurements of dissolved oxygen (DO), temperature,
specific conductance, pH, and Eh.  Also, field personnel
measured the depth to water in the monitoring wells and
piezometers to determine the elevation of the piezometric
surface and evaluate the hydraulic gradient in the vicinity
of the treatment system.

The first sampling event (June 6 through 8) was performed
after at least two pore volumes of groundwater had passed
through the reactive  iron, assuming  a minimum flow
velocity of about 0.4 foot per day (see Section 2.1.7).  One
pore volume equals the volume of saturated pore space of
the reactive iron medium and is estimated by the developer
as about 40 to 45 percent of the total volume of the reactive
iron  medium, or about 1,200  gallons  in this  case.
However, based on subsequent inspection of the June data,
a sufficient amount of water had not yet passed through the
system before the  June sampling  event to allow the
downgradient wells (MW-D1 through D-6) to accurately
represent treated groundwater conditions. For this reason,
the usefulness of the June data is limited (see Section 2.1).

1.6   Postdemonstration Activities

Interpretation of data gathered from  the  piezometers
during the SITE demonstration regarding groundwater
flow velocity was  complicated by several factors (see
Section 2.1.7).  For this reason, approximately 6 months
after the  SITE demonstration was completed, personnel
from ETI and S&W performed a bromide tracer study to
provide a more accurate determination of the groundwater
flow velocity and the residence time in the reactive iron.
ETI subsequently performed another study in November
1996 using a downhole flow meter to attempt to confirm
the groundwater flow velocity.  These studies  were not
performed under the supervision of the SITE Program; for
this reason, the test procedures are not discussed in detail in
this ITER. However, ETI's results are discussed in Section
2.1.7.

1.7   Key Contacts

Additional  information   on  the   metal-enhanced
dechlorination process, ETI, the SITE Program, and the
New  York  demonstration site  is available  from the
following sources:

Metal-Enhanced Dechlorination Process
John L. Vogan
Project Manager
EnviroMetal Technologies, Inc.
42 Arrow Road
Guelph, Ontario, Canada NIK 1S6
(519) 824-0432

SITE Program
Dr. Chien T. Chen
Project Manager
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
2890 Woodbridge Avenue, Bldg. 10
Edison, NJ 08837-3679
(908) 906-6985

Annette M. Gatchett
Associate Director of Technology
U.S. Environmental Protection Agency
Land Pollution and  Remediation Control Division
                                                   18

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National Risk Management Research Laboratory
26 West Martin Luther King Jr. Drive (MD 215)
Cincinnati, OH 45268
(513) 569-7697

New York Demonstration Site
Diane Clark
Senior Engineer
Stearns & Wheler, L.L.C.
One Remington Park Dr.
Cazenovia, NY 13035
(315) 655-8161
                                                  19

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                                             Section 2
                           Technology Effectiveness  Analysis
This section addresses the effectiveness of the metal-
enhanced  dechlorination  technology  for  treating
groundwater contaminated with chlorinated VOCs. This
evaluation of the technology's effectiveness is based
mainly on the demonstration results  supplemented by
additional performance data from other applications of
this technology and postdemonstration data obtained by
ETI.

Vendor claims regarding the effectiveness of the metal-
enhanced dechlorination  technology  are presented in
Appendix A. Case studies that describe other applications
of the metal-enhanced dechlorination technology are
presented in  Appendix B.    Tables  summarizing the
laboratory analytical  data  for  groundwater  samples
collected during  the  demonstration  are included in
Appendix C.

2.1    SITE Demonstration Results

This section  summarizes the results  from the SITE
demonstration  of the  metal-enhanced dechlorination
technology for both critical and noncritical parameters,
and is organized according to the project objectives stated
in Section 1.5.5.  Sections 2.1.1 and  2.1.2 address the
primary objectives,  and Sections 2.1.3 through 2.1.7
address secondary objectives.  Table 2-1 summarizes the
key demonstration results with respect to the  project
objectives and summarizes the evaluation criteria for each
objective.

The   analytical  data  for  samples   collected  from
downgradient wells MW-D1, D2, and D3 in June (about 2
weeks after the treatment wall was  constructed) were
inconsistent with data collected from the same wells in
subsequent months, and do not appear to be representative
of actual treated effluent concentrations. For example, as
shown in Table C-l in  Appendix C, the average cDCE
concentration in wells MW-D1, D2, and D3 in June was
30.7 ug/L; however, as shown in Tables C-2 through C-6,
the cDCE concentration in these wells  in subsequent
months ranged from about 1.6 to 7.5  ug/L. The treatment
cell was dewatered during construction; when the sheet
piling  was  first  removed  from  the  upgradient  and
downgradient sides of the cell groundwater flowed back
into the cell from both the upgradient and downgradient
sides. The June analytical data appear to  indicate that a
sufficient quantity of water had not yet passed through the
wall to completely flush residual, untreated water from the
downgradient pea gravel zone. For this reason, the June
data were not used to determine average concentrations
and are not discussed in detail for most parameters.

Critical  VOCs  consistently  detected  in the  influent
groundwater during the demonstration were TCE, cDCE,
VC, and TCA. TCE was consistently detected in all of the
upgradient wells at concentrations ranging from 32 to 330
ug/L; concentrations of cDCE ranged from 98 to 550 ug/
L, and concentrations of VC ranged from 4.7 to 79 ug/L.
TCA was detected in one or more upgradient wells during
all months of testing at relatively low concentrations (3.3
to 13 ug/L). Trace concentrations of tDCE (1.2 to 2.2 ug/
L) were detected in one or more upgradient wells during all
months except December. PCE was not detected in any of
the groundwater samples.

The average concentrations of all critical parameter VOCs
(with the exception of PCE) were determined for the
influent  (upgradient)   and  effluent  (downgradient)
groundwater samples. The average values, as well as the
individual,  monthly data  for   each  parameter,  were
compared to target levels to support objective PI, and were
used to  calculate  the system removal efficiency (RE)
values to support objective P2. More detailed information
regarding data interpretation methods is presented in the
QAPP and in the TER.
                                                   20

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Table 2-1.  Demonstration Results with Respect to Objectives
  Objective
Description/Purpose
Evaluation Criteria
                                                                                                                  Results
  P1        Determine if the technology achieves
            target levels for critical VOCs (PCE,
            TCE, cDCE, tDCE, TCA, and VC)
  P2        Determine removal efficiency for
            critical VOCs
  S1        Determine concentration gradients of
            critical VOCs
  S2        Evaluate changes in inorganic and
            noncritical VOC concentrations as
            groundwater moves through treatment
            cell
  S3        Document geochemical conditions as
            groundwater moves through treatment
            cell

  S4        Examine biological microorganism
            growth in the wall

  S5        Document operating and design
            parameters
                           VOC concentration data from downgradient
                           (effluent) wells MW-D1, D2, and D3 for the
                           period after system performance became
                           relatively stable (July through December
                           1995)

                           Comparison of VOC data (July through
                           December 1995) from upgradient wells MW-
                           U1, U2, and U3 to data from downgradient
                           (effluent) wells MW-D1, D2, and D3

                           Comparison of VOC data from upgradient
                           (MW-U1, U2, U3), iron (MW-Fe1, Fe2, Fe3),
                           and downgradient (MW-D1, D2, D3)
                           monitoring wells
                           Comparison of inorganic and noncritical VOC
                           data from same wells as objective S1, plus
                           three wells outside (downgradient) of
                           treatment cell (MW-D4, D5, D3) (metals only)
                           Comparison of field parameter results from
                           same wells as 82
                           Comparison of phospholipid fatty acid data
                           from same wells as S3

                           Groundwater flow velocity (piezometric data
                           from all monitoring wells plus piezometers P-
                           1 through P-8); construction observations;
                           bulk density analysis of iron
                             Average effluent concentrations were all below target levels; four
                             cDCE results out of 15 measurements slightly exceeded target
                             levels; in all cases effluent concentrations were significantly lower
                             than influent concentrations
                             High removal efficiency for critical VOCs present at significant
                             concentrations in the influent (TCE, cDCE, and VC); no apparent
                             decrease in removal efficiency over demonstration period
                             Most critical VOCs were nondetectable in the iron wells, indicating
                             that the iron wall was thick enough to allow sufficient residence
                             time fordechlorination; also, no measurable increase in typical
                             dechlorination by-products as groundwater passed through the
                             system

                             Bicarbonate alkalinity, calcium, and several other inorganic
                             parameters decreased as water moved through the system,
                             indicating precipitation of metal compounds; one noncritical VOC
                             (DCA) was detected at low concentrations in the influent, and was
                             not detected in the iron wells or downgradient wells

                             Increases in pH and decreases in Eh and conductivity were
                             observed during all months, suggesting conditions were
                             conducive to metal precipitation

                             Data do not indicate significant biological activity in iron
                             About 430 cubic feet of iron used; uncompacted bulk density
                             measured at 140 pounds per cubic foot; low horizontal gradient
                             indicated possible slower groundwater flow velocity and longer
                             residence time in iron than anticipated
 Notes: P - Primary Objective
                S- Secondary Objective

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        Table 2-2.  Summary of Critical VOC Concentrates at Effluent Sampling Locatioos
                                                    Concentration Detected Purina Month
to
to


VOC
TCA
PCE
TCE
cDCE
tDCE
VC



VOC
TCA
PCE
TCE
cDCE
tDCE
VC

June2
MW-D1 MW-D2
<1.0 <1.0
<1.0 <1.0
52 L3
24 28
<1.0 <1.0
1.3 2J.


October
MW-D1 MW-D2
<1.0 <1.0
<1.0 <1.0
1.2 1.5
5 Lง
<1.0 <1.0
<1.0 1.2
Overall
11 A Mean
Ju|y Au9ust Effluent
MW-D3 MW-D1 MW-D2 MW-D3 MW-D1 MW-D2 MW-D3 Value3
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
fLS <1.0 <1.0 <1.0 3.3 <1.0 <1.0 <1.3
3Q 2.2 3.7 3.9 _g_ 1.6 1.9 3.9
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
1.6 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0
Concentration Detected During Month

November December Sen?
MW-D3 MW-D1 MW-D2 MW-D3 MW-D1 MW-D2 MW-D3 Values3
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 AIK1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 All<1.0
<1.0 1.6 <1.0 <1.0 0.91J <1.0 <1.0 0.91J-3.3
2 4.6 4.2 2.8 2.5 5JJ ง4 1.6-7.5
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 All<1.0
<1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0-1.2
Taiget Effluent
Levels
MCL<
200
5
5
70
100
2

Overall
NYSDEC5
5
5
5
5
5
2

Target Effluent
Mean Levels:
Effluent
Value3
<1.0
<1.0
<1.3
3.9
<1.0
<1.0
MCL1 NYSDEC5
200 5
5 5
5 5
70 5
100 5
2 2
        Notes:  All values are presented in micrograms per liter.
                For monthly samples, "<" (less than) symbol indicates that a compound was not detected;  corresponding value is detection limit and is value used to
                calculate overall mean.
                Overall mean values based on one or more "nondetects" are also reported as "<" {less than) corresponding value.
                Values exceeding at least one applicable target effluent standard are shown underlined.
                J = Value estimated; concentration detected is below minimum quantitation limit.
                1    1,1,1-trichloroethane (TCA); tetrachloroethene (PCE); trichloroethene (TCE); cis-1,2-dichloroethene (cDCE); trans-1,2-dichloroethene (tDCE)-
                    and vinyl chloride (VC).
                2    June data were collected before representative effluent (downgradient) conditions were attained, and are not used to determine average values.
                3    Value based on data collected from wells MW-D1, D2, and D3 from July through December.
                4    MCL = federal maximum contaminant level.
                5    NYSDEC = New York State Department of Environmental Conservation groundwater discharge standard.

-------
2.1.1  Objective P1:  Compliance with
       Applicable Effluent Target Levels

Compliance with the target levels was  evaluated by
comparing the critical parameter concentrations detected
in downgradient wells MW-D1, D2 and D3 during July,
August, October, November,  and  December, and  the
average value for each contaminant detected in these
wells,  to  federal MCLs  and NYSDEC groundwater
discharge standards.

The detection limit for all critical parameters  in  the
effluent samples  was 1 ug/L, and most of the samples
collected  from   the  downgradient  wells during  the
demonstration did not contain detectable concentrations
of critical contaminants, with the exception of cDCE, and,
less frequently, TGE and VC.  Ten out of 15 TCE results
for the period from July to December were  below
detectable limits,  as were 13 put of 15 VC results for the
same period.  Low concentrations of cDCE were detected
in wells MW-D1,  D2, andDS during each sampling event.
All critical VOC  concentrations measured in  individual
wells from July through December were below MCLs.
Critical VOC concentrations were also below NYSDEC
target  levels  in most   instances   (86  out  of  90
measurements).  Only one contaminant, cDCE, slightly
and sporadically exceeded the NYSDEC target effluent
level of 5 |jg/L during this period (well MW-D1  during
August, well MW-D2 in October, and wells MW-D2 and
D3 in  December).   However,  the maximum  cDCE
concentration detected in any of the downgradient samples
collected from July to December was relatively low (7.5
ug/L) and in all  cases was significantly  less than  the
influent cDCE concentration detected  during the same
month.

Overall, concentrations of all  critical  contaminants,
including VOCs such as cDCE, tDCE and VC, which are
potential by-products of the dechlorinatioh of TCE, were
significantly  lower  in downgradient  wells  than  in
upgradient wells.  For this reason, the VOC data appear to
indicate that residence time was  sufficient to allow  the
technology to dechlorinate any  by-products  generated
through the jdechlorination of TCE.

2.1.2  Objective P2:  Critical Parameter
       Removal Efficiency

The  efficiency with which the in-situ metal-enhanced
dechlorination process removed contaminants  from
 groundwater was evaluated by  comparing the average
 upgradient and average downgradient concentrations of
 the six critical parameter VOCs: TCA, TCE, PCE, cDCE,
 tDCE, and VC.  Removal efficiency for each compound
 was evaluated for each of the five data sets collected after
 system performance appeared to stabilize (July, August,
 October, November, and December).   Overall  system
 removal efficiency for each compound, based on values
 averaged for each parameter for the period from July
 through  December, was also calculated.  The average
 upgradient   and  downgradient   critical  parameter
 concentrations for each month, the overall average values
 and the removal efficiency data are presented in Table 2-3.

 In cases where effluent concentrations of a compound
 were nondetectable, the detection limit value (1.0 ug/L),
 rather than an assumed concentration of 0.0 ug/L, was
 used to calculate the minimum removal efficiency. This
 conservative practice, which was specified by the QAPP,
, was adopted to ensure that the removal efficiency would
 not be overestimated, and assumes that a compound  not
 detected in the effluent at a detection limit of 1.0 ug/L may
 have been present at a concentration between 0.0 ug/L and
 1.0 ug/L. For this reason, the removal efficiency values in
 Table 2-3 are the minimum possible values and may be
 lower than the actual removal efficiencies achieved by the,
 system. For example, as shown in Table 2-3, although VC,
 was not detected in any downgradient wells in August the
 minimum removal efficiency was not reported as "100
 percent."  Instead, the  removal  efficiency for VC was
 based on an assumed average downgradient concentration
 of 1.0 ug/L and was  reported  as "greater than 91.1
 percent", indicating that the actual value lies in the range
 between 91.1 percent and 100.0 percent.

 The removal efficiency calculations are also influenced by
 the magnitude of the influent concentrations relative to the-
 detection limit value (1.0 ug/L) assigned as the effluent
 concentration  for  nondetect  situations.     If low
 concentrations of a VOC (for example tDCE or TCA),
 were present in the influent, the assigned effluent value of
 1.0 ug/L was  greater in proportion  to  the influent
 concentration  than in  cases  where  higher  influent
 concentrations were present (as for cDCE or TCE). For
 this reason, situations involving low influent concentrations
 typically resulted in lower calculated removal efficiency
 values, even though the contaminant  was reduced to
 nondetectable levels in the effluent.

 The results presented in Table 2-3 indicate that removal
 efficiency was high for all  contaminants  present  at
                                                  23

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Table 2-3. Summary of Critical Parameter Removal Efficiency: July-December 1995
 Average
Upgradient
  July
  Average
Downgradient
                                                   Removal
 Average
Upgradient
  August
  Average
Downgradient
                                                                                          Removal
                     Concentration   Concentration   Efficiency   Concentration   Concentration   Efficiency
VOC
TCA
PCE
TCE
cDCE
tDCE
VC
(ug/L)1
<2.2
<1
180.0
290.0
<1.1
19.0
(gg/L)2 (%)3
<1 >54.5
<1 NC
<1 >99.4
3.3 98.9
<1 >9.0
<1 >94.7
(ug/L)1
4.9
<1
183.3
306.7
<1.4
11.3
(M9/L)2 (%)3
<1 >79.5
<1 NC
<1 .8 >99.0
3.2 99.0
<1 >28.5
<1 >91.1
                                    October                                November
                        Average       Average                  Average       Average
                       Upgradient    Downgradient    Removal    Upgradient    Downgradient   Removal
                      Concentration   Concentration   Efficiency   Concentration  Concentration  Efficiency
                                                                (ua/L)1         (ug/L)2
TCA
PCE
TCE
cDCE
tDCE
VC
7.1
<1
143.3
380.0
1.8
60.3
<1 >85.9
<1 NC
<1.3 >99.0
4.8 98.7
<1 >44.4
<1.1 >98.1
4.9
<1
69.0
159.3
<1.3
14.3
<1 >79.5
<1 NC
<1.2 >98.2
3.9 97.6
<1 >23.0
<1 >93.0
                                  December
                                                            Overall Minimum Removal Efficiency for
                                                                    Demonstration Period;




VOC
TCA
PCE
TCE
cDCE
tDCE
VC
Average
Upgradient
Concentratio
n
(M9/L)1
12.3
<1
120.0
230.0
<1
21.7

Average
Downgradient
Concentration
(ug/L)2
<1
<1
<1
4.5
<1
<1


Removal
Efficiency
(%)3
>91.8
NC
>99.1
98.0
NC
>95.3

Overall Mean
Influent
Concentration
(M9/L)4
<6.3
<1.0
139.1
273.2
1.3
25.3

Overall Mean
Effluent
Concentration
(U3/L)5
<1.0
<1.0
<1.3
3.9
<1.0
<1.0


Minimum Removal
Efficiency
(%)6
>84.1
NC
>99.0
98.6
NC
>96.0
    Notes:
         :                                                                                  ,  ,
         averaga value is less than value shown; applies to instances where one or more values used to calculate average were
        "nondetect" and were assigned the detection limit concentration of 1pg/L.
       > ปIndicates that removal efficiency is based on one or more "nondetect" values and is greater than value shown.
       NCS removal efficiency not calculated; contaminant was not consistently detected in influent samples or effluent samples.
       Monthly average of concentrations detected in upgradient wells MW-U1, U2. and U3-
       Monthly average of concentrations detected in downgradient wells MW-D1, D2, and D3.
       Monthly removal efficiency = 100 X [average upgradient concentration - average downgradient concentration]/ average
       upgradient.
       Mean of concentrations detected in upgradient wells MW-U1, U2, and U3 from July through December.
       Mean of concentrations detected in downgradient wells MW-D1, D2, and D3 from July through December.
       Overall minimum removal efficiency (RE) for each parameter is based on data  collected from July through December and
       calculated using the following formula: Minimum RE = 100 X [Mean Influent Concentration - Mean Effluent
       Concentratton)/Mean Influent Concentration).
                                                         24

-------
significant concentrations in the influent (TCE, cDCE, and
VC).  The minimum monthly removal efficiencies for
TCE ranged from greater than 98.2 percent to greater than
99.4 percent, and the overall minimum removal efficiency
was greater than 99.0 percent. For cDCE, monthly values
ranged from 97.6 percent to 99.0 percent, and the overall
minimum removal efficiency was 98.6 percent. Monthly
removal efficiency values for vinyl chloride ranged from
greater than 91.1 percent to greater than 98.1 percent, with
overall minimum removal efficiency greater than 96.0
percent.  Monthly and overall removal efficiency values
were not calculated for PCE because no PCE was detected
in the influent or effluent samples during any month of
testing.

Figure 2-1 shows  the  calculated minimum monthly
removal efficiency values for the critical contaminants
present at significant concentrations in the influent (TCE,
cDCE, and VC).  As indicated on Figure 2-1, there did not
appear to be any significant trends in the monthly system
removal efficiency  for any of these contaminants from
July to December. Figure 2-1 reflects a slight decrease in
calculated removal efficiency for these three parameters in
November; however, the  apparent decrease merely
                                            reflects a decrease in influent  concentrations.   This
                                            observation  is  significant because  the  results  of the
                                            inorganic analyses (see Section 2.1.4) suggest that metal
                                            compounds were precipitating in the iron as groundwater
                                            passed through the system. Precipitates did not noticeably
                                            affect  system performance  with respect to removal
                                            efficiency during the period of the SITE demonstration.

                                            2.1.3 Objective S-1: Critical Parameter
                                                   Concentrations as a Function of
                                                   Sampling Location (Distance)

                                            Figures 2-2  through 2-7 plot concentrations of  critical
                                            contaminants relative to distance as groundwater moved
                                            through the  system.   Data from each group  of wells
                                            (upgradient,  iron, and  downgradient) were averaged for
                                            each month to facilitate presentation of data in Figures 2-
                                            2 through 2-7.  The  three data  points on each graph
                                            represent the upgradient pea gravel (distance x==0 feet; iron
                                            (x=2.4 feet); and downgradient pea gravel (x=4.8 feet).
                                            Only those critical contaminants consistently detected in
                                            the influent samples are plotted in Figures 2-2 through 2-
                                            7.
             100
ฃ
I
              96
              94
              92
              90
                                                                            \
                                                                             V"


                 1               2              3               456
                                               Month (July = 1)


                                           • TCE   ซ> cDCE  A VC

          KB calculated for months after performance stabilized (July - December); no data collected in month 3 (September);
             RE based on average values for upgradient (MW-U1,2 and 3) and downgradient (MW-D1,2, and 3) wells.


Figure 2-1. Critical VOC removal efficiency over time.
                                                   25

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                   200
                   150
                    50
                                           cDCE  • TCE   ATCA   0VC
Figure 2-2.  Critical VOCs vs. distance-June.
                                                                                               1
                                                  Distance (Feet)
                   400
                                                
-------
                     400
                  ^ 300 -
                     200  -
                                            cDCE +TCE   &TCA   oVC
                     100 -
                                                   Distance (Feet)
Figure 2-4.  Critical VOCs vs. distance-August.
                     400
                     300
                     200
                 1
                     100
*cDCE
                                                              TCA  *VC
                                                                                            80
                                                  60



                                                     1


                                                  40 >
                                                     •B
                                                                                           20
                                                  Distance (Feet)
              ug/L=micrograms per liter; values are averages for: upgradient pea gravel (X=0 ft); iron (X=2.4 feet)

                  and downgradieat pea gravel (X=4.8 feet); non-detect values plotted as detection limit (1 ug/L).
Figure 2-5. Critical VOCs vs. distance-October.
                                                         27

-------
                    200
                                            cDCE  +TCE   A-TCA   ฉVC
                                                   Distance (Feet)
Figure 2-6. Critical VOCs vs. distance-November.
                                           cDCE • TCE    ATCA   0VC
                                                   2           3
                                                   Distance (Feet)
                  ug/L=micrograms per liiter; values are averaged for: upgradient pea gravel (x=0 feet); iron (X=2.4
                  feet); and downgradient pea gravel (x=4.8 feet). Nondetect values plotted as detection limit (1 ug/L).
 Figure 2-7. Critical VOCs vs. distance-December.
                                                          28

-------
Concentrations of critical parameters present at significant
concentrations in the influent (TCE, cDCE, and VC) were
significantly reduced as groundwater moved through the
wall. As shown in Figures 2-2 through 2-7, in most cases,
contaminants were reduced to nondetectable levels by the
time groundwater had traveled about halfway through the
iron wall. Some low concentrations of cDCE appeared to
persist;  however,  during  all  months cDCE  was
significantly reduced relative to influent concentrations.
In several instances (for example, TCE in October), all
concentrations in the iron wells were at  nondetectable
levels; however, trace concentrations appeared in the
downgradient wells. The presence of low concentrations
of TCE, cDCE, and other compounds in the downgradient
wells may have been caused by residual VOCs in the
natural aquifer materials on the downgradient side of the
cell continuing to leach minor amounts of  chlorinated
VOCs into groundwater, and some of this water mixing
with treated water in the downgradient pea gravel zone.

The results of a previous demonstration of an aboveground
application of the metal-enhanced dechlorination process
indicated that chlorinated VOCs were persisting for longer
periods (greater distances) in the iron as the demonstration
progressed, possibly due in part to precipitate formation
(EPA 1997).  However, for the in-situ system, the VOC
data do not appear to exhibit significant trends indicative
of changes in the iron's ability to dechlorinate the critical
contaminants. Critical VOC concentrations in monitoring
wells MW-Fel,  MW-Fe2, and MW-Fe3, which were
located approximately halfway  through the reactive iron
wall (in the  direction of groundwater flow)  did not
increase significantly during the demonstration period.
Although the results of the inorganic analyses suggest that
metal compounds  were  precipitating as groundwater
moved through the iron, these precipitates did not cause a
noticeable reduction in the iron's performance during the
demonstration  period.    Differences  between the
performance of the aboveground reactor and that of the in-
situ system may have been due to differences between the
residence  times for groundwater in the  two systems;
differences in contaminant loading for the two systems;
variations between  groundwater chemistry at the two
demonstration sites, or other factors.

Precipitate formation may have  been less significant of a
factor in the demonstration of the in-situ system than in the
demonstration of the aboveground reactor because the
volume of water treated, flow  rate, mass  of iron used,
groundwater chemistry, length  of demonstration period,
 and other factors differed between the two demonstrations.
 Also, based on the apparent groundwater flow velocities,
 the reactive iron wall was probably thicker than necessary
 to dechlorinate the concentrations of VOCs detected in the
 upgradient wells,  and therefore had  excess  treatment
 capacity. This factor, and the availability of only one row
 of measuring points in the reactive iron may have allowed
 changes in the first few inches of iron on the upgradient
 side of the wall to go undetected during the demonstration
 period.

 In summary, the data indicate two key findings with regard
 to objective S-l:  1) because  most contaminants  were
 reduced to nondetectable levels by the time groundwater
 had traveled halfway through the reactive  iron, the
 thickness of the reactive iron wall appeared to be more
 than adequate  to  allow sufficient residence  time for
 dechlorination to occur; and 2) the dechlorination of TCE
 and cDCE  was not causing increased concentrations of
 potential by-products (cDCE and VC) in the downgradient
 wells, indicating that the iron was dechlorinating all of
 these compounds.

 2.1.4  Objective S-2: Noncritical  VOCs,
        Metals, And Other Inorganic
        Parameters

 Tables Cl through C6 in Appendix C summarize all of the
 laboratory   analytical  data  collected  during   the
 demonstration, including the  results of the noncritical
 VOC, metals,  and other inorganic parameter  analyses.
 Specifically, these parameters were analyzed to evaluate
 effects of the reactive iron on noncritical parameters, and
 to provide  additional  data about the  dechlorination of
 VOCs, metal precipitation, and the potential for biological
 growth.  Due to  the extensive  number  of analytical
 parameters   and sampling  points  pertaining  to   this
 objective,  only results for significant parameters  are
presented in graphical format.

 Noncritical VOCs

The samples were  analyzed for a total of 64 VOCs on
EPA's  Target Compound  List  (TCL);  tentatively
identified compounds (TICs) were also reported. The only
 significant noncritical VOC consistently detected in the
upgradient,  influent groundwater was DCA,  which was
detected at low concentrations (less than 6 ug/L) during all
months of testing. DCA was below detectable levels in the
                                                   29

-------
iron wells in all but two cases (MW-Fe3 in November and
December), and was below detectable levels in all of the
downgradient wells during these months. In all instances,
DCA concentrations in the iron wells and downgradient
wells were below the applicable NYSDEC  and MCL
standards, both of which are equal to 5.0 ug/L.  This
observation is consistent with ETI's past research data,
which  indicated that the reactive iron is capable  of
dechlorinating DCA (Focht,  Vogan,  and O'Hannesin
1996).

As indicated in Table C-2, during July TCE  and cDCE
were detected in a sample from well MW-D4, and TCE,
cDCE, and VC were detected in a sample from well MW-
D5.  VOC sample fractions were collected from these
wells  solely  to provide  information  to  support the
demonstration health and safety program. The QAPP did
not specify collection of VOC sample fractions from these
wells to support primary or secondary objectives; for this
reason, the results are not critical parameters and are not
discussed in detail in this report.  However, it should be
noted that both wells MW-D4 and MW-D5 are located
outside of the treatment cell, and  the  VOC  sample
fractions  were   collected  relatively  early  in  the
demonstration (July).  As previously discussed, possible
mixing of treated groundwater and residual, untreated
water may have resulted in the presence of VOCs in
samples from these wells.

Metals

The groundwater samples were analyzed for a total of 16
metals  using  inductively-coupled plasma (ICP) and
atomic absorption (AA) techniques. Data for several of
the metals detected appear to indicate trends indicative of
precipitate formation.  These metals include calcium,
magnesium, barium, iron, and manganese.

Figures 2-8 and 2-9 summarize the average calcium and
magnesium concentrations in each row of wells (including
the downgradient wells screened hi the natural aquifer
materials) from June  through December.  Figure 2-10
summarizes the average  calcium and magnesium data
collected  from each row after system  performance
stabilized (July through December).  As shown by the
figures, influent concentrations of each of these metals
exhibited relative consistency among months. During all
months, concentrations of calcium generally decreased
between the upgradient wells and the iron wells, and then
appeared to gradually increase in the downgradient pea
gravel and aquifer wells.   The  decrease in calcium
concentrations coincided with a decrease in bicarbonate
alkalinity  and  an increase in measured pH values,
suggesting that geochemical conditions in the iron were
conducive  to  decreased  solubility   and  increased
precipitation  of calcium  carbonate  and other metal
compounds onto the iron.

Magnesium  concentrations  also  generally  decreased
between the upgradient pea gravel and reactive iron;
however, unlike  calcium,  magnesium  concentrations
continued to decrease as groundwater moved through the
downgradient pea gravel, and then increased slightly in the
downgradient aquifer.  This observation suggests that
magnesium  compounds  continued to  precipitate  as
groundwater moved downgradient from the reactive iron
zone.  The  slight increase  observed in magnesium
concentrations downgradient from the cell may be due to
mixing of treated and untreated water downgradient of the
cell. Also, samples collected from wells MW-D4, D5 and
D6, which were screened in the natural aquifer materials,
generally appeared to contain a higher concentration of
suspended sediments than samples from wells screened in
the pea gravel or iron. These suspended fines may have
affected the analyses as the samples were not filtered
before analysis.

Iron and manganese concentrations are plotted in Figures
2-11 through 2-13.  As evidenced by the figures, the
samples from wells in the reactive iron typically contained
the highest iron concentrations of the four rows monitored.
This is consistent with the nature of the proposed reaction
mechanism (see Section  1.3)  which suggests that the
oxidation of iron and the hydrolysis of water will cause
iron compounds such as Fe(OH)2 and FeCO3 to form, and
then subsequently precipitate out due to the elevated pH
levels.   In  August, November,  and  December  iron
concentrations in  the downgradient aquifer wells were
higher than background  concentrations  but  were still
relatively low (less than 1 mg/L). However, during June,
July, and October, iron concentrations in the downgradient
aquifer wells were below  background levels. For this
reason, the  iron  data  to  not  strongly indicate trends
regarding the persistence of dissolved iron as groundwater
moved downgradient in the aquifer.

Unlike iron,  manganese  concentrations appeared  to
decrease between the upgradient pea gravel and reactive
iron  zones,   and then   gradually  increase  in   the
downgradient wells. The cause for the apparent behavior
                                                    30

-------
Month
• UG (Gravel)
cTIron
B DG (Gravel)
• DO Aquifer
June
77.00
14.77
19.07
82.77
~My —
89.20
14.60
17.97
29.2
August
88.30
10.14
17.53
26.57
October
92.17
8.83
17.10
41.20
November
89.10
8.32
14.67
34.30
December
91.27
10.76
"17.67
35.30
                       mg/L = milligrams per liter; UG = upgradient; DG = downgradient
 Figure 2-8.  Summary of calcium data over time.
Month
i UG (Gravel)
olron
a DG (Gravel)
• DG Aquifer
June
12.03
5.68
2.88
18.36
Julv
12.47
10.77
5.37
4.20
August
12.43
10.23
5.38
4.61
October
12.30
9.73
4.92
6.21
November
11.93
8.91
4.25
5.62
December
"' 12.83
8.67
5.46
6.46
                          mg/L = milligrams per liter; UG=upgradient; DG=downgradient
Figure 2-9. Summary of magnesium data over time.
                                                   45678
                                                      Distance (feetj
9    10  11   12
                                                   Calcium     -ป. Magnesium
                    mg/L = milligrams per liter; values based on July-December, averaged for: upgradient (X=0 ft),
                        iron (x=2.4 ft); downgradient (x= 4.8 ft), and downgradient aquifer (x= 10.7 ft) wells.

Figure 2-10. Average calcium and magnesium values vs. distance.
                                                            31

-------
                                  0.01
Month
• UG (Gravel)
a Iron
B DO (Gravel)
• DG Aquifer
June
4.42
16.62
1.12
4.59
July
0.10
0.43
0.05
0.09
August
0.12
0.63
0.07
0.75
October
0.10
0.30
0.10
0.02
November
0.10
O.ZB
0.12
0.60
December
0.10
0.33
0.13
0.59
                       mg/L — milligrams per liter; UG — upgradient; DG = downgradient;
                            all nondetect values plotted as detection limit (0.10 mg/L)
Figure 2-11. Summary of iron data over time,

                                       1
Month
I UG Gravel
a Iron
• DG Gravel
• DG Aquifer
June
0.35
0.33
0.18
0.91
I — JW — I
0.42
0.22
0.20
0.33
August
0.43
0.17
0.23
0.38
October
0.46
0.07
0.22
0.05
November
0.36
0.05
0.13
0.44
December
0.39
cms
0.20
0.29
                           mg/L ป milligrams per liter; UG = upgradient; DG = downgradient;
 Figure 2-12. Summary of manganese data over time.
                                                      e Iron        •ป Manganese
                                    0123456789    10   11    12
                                                             Distance (feet)
                      mg/L = milligrams per liter; values based on July-December, averaged for: upgradient (X=0 ft);
                          iron (X=2.4 ft); downgradient (X=4.8 ft); and downgradient aquifer (X=10.7 ft) wells.

 Figure 2-13. Average iron and manganese values vs. distance.
                                                               32

-------
is unknown. According to ETI, this may have been caused
by naturally occurring manganese in site groundwater
being absorbed into carbonate precipitates forming as
groundwater moved through the reactive iron, or other
factors  (Vogan  1996).    Manganese  concentrations
downgradient of the wall generally appeared to be similar
to upgradient concentrations.  Overall, it does not appear
that the iron wall was introducing more manganese to
groundwater than  was  present  at naturally occurring
background levels.

As shown in Figure 2-14, barium concentrations generally
increased between the upgradient pea gravel wells and the
iron wells, and then declined. However, the magnitude of
the increase in barium lessened with each month.  The
possible cause of this observation is unknown, but may be
a residual effect of the  cell construction activities that
lessened with time as groundwater continued to "flush"
the reactive iron.    According to ETI,  after initial
emplacement the iron may have temporarily leached small
amounts of barium into groundwater passing through the
wall (ETI 1997). However, barium did not appear to be
persisting into the downgradient aquifer; barium levels
generally decreased between the reactive iron wells and
the downgradient wells.

Other Inorganic Parameters

Other  inorganic  parameters  (bicarbonate  alkalinity,
sulfate, chloride, nitrate, and nitrite were measured in the
upgradient pea gravel, iron, and downgradient pea gravel
wells.

Figures 2-15 and 2-16  plot the average  bicarbonate
alkalinity concentrations in the various rows of wells. The
results indicate that bicarbonate  alkalinity decreased as
groundwater  moved  through  the reactive  iron  wall,
coinciding with an  increase in pH, and then increased
slightly  as groundwater moved downgradient.  This
behavior is consistent with the results of the  calcium,
magnesium, and pH analyses, which suggested that metal-
carbonate compounds were precipitating out. Figure 2-16
graphically exhibits the relationship between bicarbonate
concentrations and pH. According to Reardon (1995), as
pH increases, hydroxide (OH~) ions react with bicarbonate
ions (HCO3~) to form carbonate ions (CO.,)2", which then
may combine with iron, calcium, magnesium, and other
metals to form metal-carbonate precipitates. Equation 2-
1 shows the formation of calcium carbonate through this
mechanism:
   HCO3-
                 CaCO3(s)
(2-la)
(2-lb)
The slight increase in bicarbonate in the downgradient pea
gravel wells is consistent with the slight drop in pH and
increase in calcium concentrations observed.  These
observations  indicate  that  the  tendency  for metal
carbonates  to precipitate was decreasing as groundwater
passed out of the treatment cell.

As shown in Figure 2-17, influent sulfate concentrations
were generally consistent over the demonstration period,
ranging from about  14 to 20 milligrams per liter (mg/L),
and generally appeared to decrease as groundwater moved
through the treatment cell  during  all months.    The
reduction in sulfate concentrations appeared to be more
complete  and  was occurring more  rapidly as the
demonstration progressed.   For example, in July the
average sulfate concentrations in the upgradient, iron, and
downgradient wells were 16.8,  15.5,  and 10.6 mg/L,
respectively.   In December the average  upgradient
concentration was  consistent with July (16.6 mg/L);
however sulfate was nondetectable in the iron wells and in
the downgradient wells.

Sulfate concentrations were measured to evaluate, in part,
the potential for sulfate-reducing bacterial growth and
precipitation of metal sulfates. According to ETI, sulfate
reduction may indicate biological activity in the reactive
iron.  However,  the PLFA analyses did not indicate
significant  microbial activity  in the reactive iron (see
Section 2.1.6); therefore, it is unknown if the decrease in
sulfate concentrations was due to biological activity  or
other  causes,  such as  precipitation  of  metal-sulfate
compounds.

Figures 2-18 and 2-19  exhibit the total  nitrate/nitrite
nitrogen results.  Total nitrate/nitrite and nitrite analyses
were performed on the samples from the nine wells in the
treatment   cell;  the total  nitrate  content was   then
determined by calculating the difference between the total
nitrate/nitrite values and the nitrite values.  Total nitrate/
nitrite  concentrations detected in  samples  from the
upgradient pea gravel wells ranged from about 0.16 to 0.47
mg/L, and gradually decreased during the demonstration.
As shown  in  Tables C-l  through C-6,  the  analyses
indicated that both nitrate and nitrite were present in the
influent groundwater. The relative proportion of each of
these  compounds  to  the total nitrate/nitrite  nitrogen
                                                    33

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                                        0.7

                                        0.6



                                      a" 0.4



                                      m 0.2

                                        0.1

                                          0
Month
• uia (uravei)
oiron
• ut> (uravei)
a uti Aquuer
June
0.021
O.593
0.020
0.092
July
0.02
0.31
0.02
0.027
August
0.02
0.25
0.04
0.02
October
o.oz
0.07
0.03
0.07
November
0.03
0.06
0.03
0.0393
December
0.02
0.05
0.03
0.04
                              mg/L — milligrams per liter; UG = upgradient; DG = downgradient
Figure 2-14.  Summary of barium data over time.

                            tJ 400
                      mg/L = milligrams per liter; UG = upgradient; DG = downgradient


Figure 2-15.  Summary of bicarbonate alkalinity data over time.


                           400
                        I
                        ฃ300(1
                           200
                            100
                        .a
                        pa    o
                                                           Bicarbonate  -*• pH
10




   P
8  13





6  K


5
                                                           2             3
                                                           Distance (feet)
                        mg/L = milligrams per liter; values based on data from July-December, averaged for:
                             upgradient (x=0 ft); iron (x=2.4 ft), and downgradient (x=4.8 feet) wells.
Figure 2-16.  Average bicarbonate alkalinity and pH vs. distance.
                                                              34

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Month
B UG (Gravel)
a lion
• DG (Gravel)
June
19.6
19.4
18.5
My
16.8
15.5
10.6
August
17.8
5.4
5.0
October
16.0
5.0
5.0
November
14.3
5.0
5.0
December
16.6
5.0
5.0
                        mg/L = milligrams per liter; UG = upgradient; DG = downgradient;
                         all nondetect values plotted as detection limit (5.0 mg/L)
Figure 2-17.  Summary of sulfate data over time.
Month
H UG (Gravel)
Dlron
• DG (Gravel)
June
0.477
0.059
0.050
July
0.366
0.050
0.050
August
0.338
0.050
0.050
October
0.256
0.050
0.050
November
0.163
0.050
0.050
December
0.230
0.050
0.050
                       mg/L = milligrams per liter; UG = upgradient; DG = downgradient;
                         all nondetect values plotted as detection limit (0.050 mg/L)
Figure 2-18.  Summary of total nitrate/nitrite data over time.
                                                                 2345
                                                                 Distance (feet)

                          Average values based on data from July - December, averaged for: upgradient (X=0 ft); iron (x = 2.4 ft);
                          and downgradient (X-4.8 ft) wells. Detection limit used to represent non-detect values for averaging data.
Figure 2-19. Average sulfate and total nitrate/nitrite values vs. distance.
                                                                    35

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content varied considerably, but indicated that nitrate was
the predominant species.  More significantly, the data
indicated that total nitrate/nitrite nitrogen was generally
not detectable in the samples from the wells screened in
the iron or the downgradient pea gravel. According to ET1,
nitrate consumption may be due to either abiotic or biotic
reduction of nitrate to nitrogen gas or ammonium (ETI
1997; PRC 1996).  The PLFA analyses did not indicate
significant biological activity in the reactive iron; this
observation  suggests that the decrease in nitrate and
sulfate concentrations  was  primarily  due to  abiotic
processes.

Chloride concentrations were determined because they
may correlate with dechlorination of VOCs.  However,
because the background chloride concentrations were
relatively  high  compared  to  the  influent  VOC
concentrations,   no  significant  trends   in  chloride
concentrations were noted during treatment as a result of
VOC dechlorination (see Tables Cl - C6).

2.1.5 Objective S-3; Eh, DO, pH,
       Specific Conductivity, and
       Temperature

Figures 2-20 and 2-21 summarize the average pH values
measured in the upgradient pea gravel, iron, downgradient
pea gravel, and downgradient aquifer sampling locations
during all months of testing. As shown on Figure 2-20,
groundwater in  the  wells screened in the reactive iron
typically exhibited the highest pH levels during all months
of testing. Generally, pH increased as groundwater moved
from the upgradient pea gravel and through the iron, and
then decreased  as  groundwater moved downgradient
Equations 1-la through 1-ld, and  l-2a through l-2g
presented in Section 1.3.1 may explain the increase in pH.
In these reactions, H* is consumed so the pH rises.

The specific conductivity of groundwater decreased  as
groundwater moved through the reactive iron, as shown in
Figures 2-22 and 2-23.  The decrease in the specific
conductivity of groundwater is probably caused by the
removal of  ions from groundwater during treatment.
Removal of ions may occur  through the formation  of
metal-hydroxide or metal-carbonate  precipitates.  The
formation of these precipitates may remove metal cations,
hydroxyl ions, and carbonate ions from the groundwater.

Generally, the  groundwater temperature data did not
indicate any significant differences among groundwater
temperatures in the various zones of the cell or in the
aquifer. However, the average temperature data indicated
a  general  decrease  in site groundwater temperature
between October and December.    This effect  is
demonstrated by the  average temperature data from the
wells  screened  in  the iron zone;  these  values  are
summarized  in  Figure 2-24.   The  temperature  of
groundwater in these wells declined about 4ฐ C between
October and December.   Because the November and
December sampling events were performed  during cold
weather, it is possible that the temperature measurements
were affected by ambient air  cooling the measuring
device. However, due to the shallow depth to groundwater
on site, a slight decrease in groundwater temperature in
winter months is  expected. As discussed in Section 3,
according to ETI, past studies involving TCE have shown
that  temperature can   influence the time required for
dechlorination to occur (ETI 1996a).  However, in this
case the slight decrease in temperature did not appear to
noticeably  affect system  performance, and  therefore
provided no additional data regarding the  effects  of
temperature on the dechlorination process. In general, in-
situ  systems are less susceptible to potentially adverse
ambine temperature effects than aboveground systems.

The  dechlorination reactions described by Equations 1-1
and 1 -2 indicate a loss of electrons from the oxidizing iron.
The groundwater Eh data, summarized in Figures 2-25 and
2-26, indicate that Eh decreased as groundwater moved
into  the  reactive  iron,  and then increased slightly  as
groundwater moved downgradient, generally following an
opposite trend to the pH data.  The trends exhibited by the
Eh data are consistent  with the known electrochemical
mechanism of the dechlorination reaction; indicating that
electrons derived from the oxidizing iron cause reducing
conditions in the groundwater.

The observed reduction of chlorinated hydrocarbons and
the decreases in metals  concentrations correlate with the
observation that reducing conditions were present.  As
previously   discussed,  concentrations  of  calcium,
magnesium, and manganese were observed to decrease
coincident with the decrease observed  in Eh and  the
increase in pH, and then generally increase as groundwater
moved downgradient from the iron wall.  However, while
trends observed in the Eh data may be indicative of metals
precipitating from groundwater moving through the iron,
changes in the iron's capacity to dechlorinate the critical
contaminants were not observed during the demonstration
period.
                                                   36

-------
                             10.00
                              5.00
Month
• UG (Gravel)
olron
• DG (Gravel)
H DG Aquifer
June
7.03
9.56
8.50
7.51
July
7.26
9.47
9.07
8.09
August
6.85
9.18
8.73
8.22
October
7.16
9.67
9.35
8.17
November
6.99
9.30
8.86
7.11
December
7.26
9.43
8.86
7.68
                  UG = upgradient; DG = downgradient
Figure 2-20. Summary of pH values vs. distance.
                           6.50
                                                 3     4     5     67    8
                                                            Distance (feet)
10    11    12
                            Values based on data collected from July - December, averaged for: upgradient (X=0 ft),
                            iron = (X=2.4 ft), downgradient (X=4.8 ft), and downgradient aquifer (X=10.7 ft) wells.
Figure 2-21. Average pH values vs. distance.
                                                          37

-------
Month
l UO (Gravel)
o Reactive Iron
I DG (Gravel)
g DG Aquifer
June
501
280
269
400
July
672
343
305
343
August
673
314
297
318
October
724
316
304
415
November
640
276
237
314
December
724
311
296
343
               UG = upgradient; DG = downgradient
Figure 2-22. Summary of specific conductivity data over time.
                     800
                                                         5678
                                                        Distance (feet)
10    11
                              Values based on data from July - December, averaged for: upgradient (X=0 ft);
                          iron (X=2.4 ft); downgradient (X=4.8 ft); and downgradient aquifer (X=10.7 ft) wells).
Figure 2-23. Average specific conductivity values vs. distance.
                                                           38

-------
                                                1         234         5          6

                                                           Month (June = 0)


                              Values based on data collected from June through December (no data collected in September);

                               values averaged for monitoring wells in reactive iron (MW-Fel, MW-Fe2, and MW-Fe3).
Figure 2-24.  Average groundwater temperature in iron wells vs. time.
Month
• UG (Gravel)
Q Iron
• DG (Gravel)
• DG Aquifer
June
223
-422
-525
18
July
246
41
-81
-85
August
203
92
-36
4
October
245
-194
^264
-165
November
30
-325
-123
-121
December
163
-405
-259
-87
                             mV = millivolts; UG = upgradient; DG = downgradient
Figure 2-25.  Summary of Eh data over time.
                             I
 200
     I




 100






   0






-100






-200
                                           1
                2    3    4    5    6    7    8    9    10   11   12

                              Distance (feet)


Values based on data collected from July - December, averaged for:  upgradient (X=0 ft);

 iron (X=2.4 ft); downgradient (X=4.8 ft); and downgradient aquifer (x=10.7 ft) wells.
Figure 2-26. Average Eh values vs. distance.
                                                               39

-------
DO data are not presented in this ITER. The field meter
used for DO measurements performed erratically, and
lacked  the  capability  of  field calibration. For these
reasons, the quality of the DO data is unknown, and the DO
data are considered unusable.

2.1.6  Objective S-4: Biological
        Microorganism Growth

According to EH and others, past studies of the metal-
enhanced dechlorination process suggest that the process
is abiotic, and biological activity does not account for a
significant amount of the chlorinated VOC reduction that
occurs.  During the New York demonstration, the SITE
team  collected  groundwater  samples  for total PLFA
analysis to confirm that the process was predominantly
abiotic,  and to  evaluate  the potential for  excessive
microorganism growth that could interfere with hydraulic
flow through the iron.  PLFA sample fractions were
collected in  June, October, and December. During each
sampling event, the SITE team prepared replicate sample
fractions for each well to minimize the potential effects of
variability.   The PLFA results for the replicate samples
from each well were averaged. These average results are
presented  in Tables C-l  through  C-6.  Figure 2-27
compares the average total PLFA concentrations for the
wells in each row (upgradient pea gravel, reactive iron,
downgradient pea gravel, and downgradient aquifer) from
each month of testing.

As in the case of the other parameters, the June PLFA data
are probably not representative of steady state conditions
in the treatment cell. Figure 2-27 shows that for June, the
average total PLFA concentration in wells in the treatment
cell was on the order of 104 to 10s picomoles/liter (pm/L).
In June there did not appear to be a significant difference
betweenthetotalPLFA hi the upgradient wells, iron wells,
and downgradient pea gravel wells. The total PLFA in the
downgradient aquifer wells was lower, on the order of 103
to 104 pm/L.  The higher PLFA in the treatment cell and the
lack of variance among the PLFA results in the various
zones of the cell may be related to residual effects of the
cell construction  activities,   and  not  indicative   of
significant long-term microorganism growth in the iron.

The October and December PLFA data appear to indicate
that the total microorganism population in each of the
three zones of the treatment cell was significantly lower
than in June. PLFA concentrations in the upgradient pea
gravel wells were on  the order of 102 to 103 pm/L  in
October, and lower yet (101 to 102pm/L) in December.
This observation may be partially due to the effects of
decreasing temperature discussed in Section 2.1.5.  Most
significantly, PLFA concentrations in the iron wells in
October and December were not significantly higher than
in the upgradient pea gravel wells, and were lower than the
PLFA concentrations in the downgradient pea gravel and
aquifer  wells.   Total  PLFA  concentrations  in  the
downgradient aquifer wells in October and December
were hi the same general range observed in June, before a
significant amount of water had passed through the cell
and migrated downgradient. These observations suggest
that once a sufficient number of pore volumes of water had
passed through the system to minimize residual effects of
construction activities, the total microorganism population
hi the pea gravel and the reactive iron was lower than in the
natural aquifer materials. For this reason, the results of the
PLFA analyses correlate with past research by  others
indicating that  the  dechlorination process is  abiotic
(Gillham and O'Hannesin 1994).

As  discussed in Section 2.1.7, the groundwater flow
velocity estimates were complicated by the low hydraulic
gradient. However, there was no measurable decrease in
flow velocity over the course of the demonstration.  Also,
system  performance  appeared to  remain  generally
consistent throughout the demonstration.   For  these
reasons, biological growth did not appear to be interfering
with the flow of groundwater through the reactive iron,
further indicating that biological activity in the iron was
not significantly greater than in the natural  aquifer
materials.

2.1.7 Objective S-5: Operating and
       Design Parameters

Table 2-4 summarizes information collected during  the
SITE  demonstration  regarding  operating  and design
parameters. The bulk density analysis of the iron indicated
an average (uncompacted) bulk density of approximately
2.25 grams per cubic centimeter, or 140  pounds per cubic
foot. About 35 to 40 tons of iron was used to construct the
cell; ETI estimates that the bulk density of the iron  in the
cell was probably greater than the laboratory-measured
value due to settling. According to ETI, typical density for
iron obtained from the supplier used for the New York
Demonstration (Master Builders, Inc.) is about 160 to 180
pounds per cubic foot after settling (ETI  1996a; 1996d;
1997).
                                                   40

-------
8
I
ง

           100000
             10000
              1000
               100
                10
                                                    /
/
	o

                                     -0-
                                           June
                                                              0 October     A December
                                          j	L
                                                          5      6       7

                                                           Distance (feet)
                                                                                        10     11      12
                      Notes: PLFA concentrations are averages for wells in following areas: upgradient pea gravel (X=0 ft);

                       reactive iron (X=2.4 ft); downgradient pea gravel (X=4.8 ft); downgradient aquifer (X=10.7 ft)
Figure 2-27. Total phospholipid fatty acids vs. distance.
                                                           41

-------
Table 2-4. Summary of Operating and Design Parameters
          Reactive Iron Medium:
                 Initial Weight (ETI)
                 Volume
                 Density (uncompacted)
                 Density, after settling, estimated (ETI)
                 Hydraulic Conductivity (ETI)
                 Porosity, after settling, estimated (ETI)
          Treatment Zone Dimensions:
                 Width (thickness) of Iron Wall
                 Length of Iron  Wall
                 Height of Iron Wall
                 Depth of Cell
                 Width (thickness) of Pea Gravel Zones
                 Length of Sheet Piling Wings
          Aquifer Saturated Thickness (average)2
          Hydraulic Gradient Across Iron Wall
          Width of Capture Zone (ETI)3
          Groundwater Flow Velocity through Iron  (range)

          Volumetric Groundwater Flow Rate (range)

          Cumulative Volume of Water Treated During
          SITE Demonstration (range)4
 About 35 to 40 tons
 400ft3
 140 Ib/ft3 (2.25 g/cm3)
 180 Ib/ft3
 142 ft/day
 0.4

 3 feet
 12 feet
 11 to 12 feet1
 14 to 15 feet1
About 1.75 feet
 15 feet each
 10 feet
Less than 0.001 to 0.002
24 feet

0.4 to 1 ft/day (ETI)
About 15.4 to 57.6 cubic feet
(115 to 431  gallons) per day

About 29,000-73,000 gallons
        Notes:
           (ETI) - designates value provided by ETI
           (range) - range of values provided due to uncertainty in piezometric measurements
           1   Top of reactive iron wall was about 3 feet below ground surface.
           2   Saturated thickness varied from about 8 to 12 feet, depending on seasonal water
              table fluctuations.
           3   Estimated width of portion of groundwater contaminant plume captured by the funnel
              and gate system.
           4   Assumes an average saturated thickness of 10 feet.
                                             42

-------
Groundwater depth measurements collected during each
of the six sampling events were converted to piezometric
elevations relative to mean sea level (MSL) to evaluate the
horizontal gradient and groundwater flow velocity.  The
piezometric elevation data are summarized in Table 2-5.
Interpretation of the piezometric data was complicated by
several factors. As evidenced by the data in Table 2-5, the
horizontal gradient measured across the study area was
extremely low, generally less than 0.001.   This  was
significantly less than the conservative (maximum) design
gradient value (0.002) used by ETI for the system design.
In most cases, due to the close spacing of the monitoring  .
wells in the treatment cell and the accuracy limitations of
the measuring equipment (0.01 foot), differences between
water levels in wells  in the  treatment cell were not
accurately measurable.  Also, after the in-situ system was
installed and the  demonstration  commenced,  S&W
detected the presence  of a liquid hydrocarbon layer,
related to a past release from a UST at the manufacturing
facility, on the water table upgradient from the treatment
system.  This layer prevented piezometric measurements
in at least three piezometers  (P-2, P-4,  and P-7) in the
southern part of the demonstration area and may  have
affected some measurements in other piezometers.1

Allowing for the limitations of the data, the measurements
indicated a generally westward flow direction across the
demonstration area, consistent with past data reported by
S&W (see Figure 2-28). Based on S&W's reported values
for hydraulic conductivity and porosity, of the natural
aquifer materials, the  observed  horizontal gradients of
0.0005  to 0.001 indicate groundwater flow velocities of
about 0.2  to 0.4 foot per day  on site in the aquifer.
According to ETI,  the  funnel and gate  configuration
typically accelerates flow velocities in the capture zone
(PRC 1997a). Assuming that thegradient in the treatment
cell was at least as high as the natural gradient on site, the
minimum estimated flow velocity through the wall was
about 0.4 foot per day.  Based on the maximum measured
gradients between the  wells in the  cell  (December), the
maximum estimated flow velocity was  about 1 foot per
 day. These estimates are based on ETI's reported design
 values  for the iron's hydraulic conductivity and porosity
 (ETI 1994).

 Due to the uncertainty regarding the groundwater flow
 velocity, ETI performed a postdemonstration tracer study
 and  a  flow-meter  study to evaluate the  flow velocity.
 These  studies  were  not  part  of the planned  SITE
 demonstration activities, and were not  performed  under
the direction of EPA.  According to ETI, the bromide
tracer study was inconclusive; however, the flow meter
study indicated a flow velocity of about 1 foot per day in
the iron zone (ETI 1996b; 1996d).

In summary, the groundwater flow velocity through the
treatment zone appears to have been between 0.4 and 1
foot per day; however, there is uncertainty regarding the
flow velocity estimates, and it is possible that the flow
velocities were below or above this range. For this reason
the exact cumulative volume of groundwater  treated
during the demonstration is unknown.  Assuming the
previously-described range  of flow velocities and  an
average saturated thickness of about 10 feet, the volume of
groundwater treated was in the range of about 29,000 to
73,000  gallons, and residence tune in the 3-foot-thick
reactive iron wall appeared to be in the range of about 3 to
7 days. Based on the predominantly nondetectable critical
parameter concentrations in the monitoring wells screened
in the iron, VOCs appear to have been reduced below
regulatory levels within the first 1.5 feet of the reactive
iron. For this reason, the high-end (conservative) velocity
estimate of 1 foot per  day indicates that  contaminant
dechlorination occurred within  36 hours; the low  end
estimate (0.4 feet per day) indicates that dechlorination
occurred within about 90 hours. In either case, the use of
a  3-foot-thick iron wall apparently provided adequate
residence time for this particular application during the
SITE demonstration period.

2.2    Additional Performance Data

In addition to the SITE  demonstration results, several
other field applications  of the in-situ metal-enhanced
dechlorination technology  were  reviewed to  provide
additional information about the process.  However, the
analytical results from these field applications have not
been subjected to EPA QA review and therefore are not
used to draw conclusions in this report. These applications
consisted of (1) the field test conducted at the Canadian
Forces Base in Borden, Ontario, Canada (Borden site); (2)
 a field  test and full-scale installation at a California
 semiconductor facility; and (3) a full-scale installation in
 Belfast, Northern Ireland. The application of the in-situ
 metal-enhanced dechlorination process in each  of these
 sites  is discussed below.    Additional  information
 regarding case studies is presented in Appendix B.

 1 S&W implemented hydrocarbon recovery operations upon discovering the
 layer. Significant amounts of petroleum-related dissolved-phase contaminants
 subsequently were not detected  and did not affect interpretation of the
 analytical data.
                                                     43

-------
Table 2-5.  PfezometrJc Data
Location
P1
P2
P3
P4
PS
P6
P7
PS
MW-U1
MW-U2
MW-U3
MW-FE1
MW-FE2
MW-FE3
MW-D1
MW-D2
MW-D3
MW-D4
MW-D5
MW-D6
TOG
EL
(feet)
99.61
100.97
99.60
99.76
99.68
99.41
101.06
100.63
98.78
98.81
98.51
98.20
98.05
98.15
98.81
98.88
98.83
99.20
99.25
98.96
TOG EL
(feet
msl)
1,050.81
1,052.17
1,050.80
1,050.96
1,050.88
1,050.61
1,052.26
1,051.83
1,049.98
1,050.01
1,049.71
1,049.40
1,049.25
1,049.35
1,050.01
1,050.08
1,050.03
1,050.40
1,050.45
1,050.16
i
DTW
7.15
8.51
7.16
7.31
7.23
6.97
9.07
8.14
6.38
6.41
6.11
6.79
5.64
5.74
6.40
6.47
6.42
6.81
6.83
6.55
5/6/95
GWEL
1,043.66
1,043.66
1,043.64
1,043.65
1,043.65
1,043.64
1,043.19
1,043.69
1,043.60
1,043.60
1,043.60
1,042.61
1,043.61
1,043.61
1,043.61
1,043.61
1,043.61
1,043.59
1,043.62
1,043.61
Z
DTW
7.96
9.30
7.97
8.11
8.03
7.75
9.95
8.93
7.15
7.18
6.88
6.57
6.42
6.53
7.18
7.25
7.21
7.59
7.62
7.34
/1Q/95
GWEL
1,042.85
1,042.87
,042.83
,042.85
,042.85
,042.86
,042.31
1,042.90
1,042.83
1,042.83
1,042.83
1,042.83
1,042.83
1,042.82
1,042.83
1,042.83
1,042.82
1,042.81
1,042.83
1,042.82
j
DTW
8.18
9.51
8.17
8.33
8.24
7.98
X
9.15
7.37
7.39
7.11
6.79
6.64
6.74
7.40
7.47
7.42
7.81
7.84
7.55
3/7/95
GWEL
1,042.63
1,042.66
1,042.63
1,042.63
1,042.64
1,042.63
X
1,042.68
1,042.61
1,042.62
1,042.60
1,042.61
1,042.61
1,042.61
1,042.61
1,042.61
1,042.61
1,042.59
1,042.61
1,042.61
U
DTW
8.33
9.86
8.32
X
8.39
8.11
X
9.31
7.51
7.53
7.24
6.92
6.80
6.87
7.54
7.61
7.57
7.94
7.97
7.69
ฅ10/95
GWEL
1,042.48
1,042.31
1,042.48
X
1,042.49
1,042.50
X
1,042.52
1,042.47
1,042.48
1,042.47
1,042.48
1,042.45
1,042.48
1,042.47
1,042.47
1,042.46
1,042.46
1,042.48
1,042.47
1
DTW
7.62
X
7.61
X
7.68
7.41
X
8.61
6.81
6.82
6.56
6.22
6.08
6.19
6.85
6.91
6.87
7.24
7.28
6.99
1/7/95
GWEL
1,043.19
X
1,043.19
X
1,043.20
1,043.20
X
1,043.22
1,043.17
1,043.19
1,043.15
1,043.18
1,043.17
1,043.16
1,043.16
1,043.17
1,043.16
1,043.16
1,043.17
1,043.17
1
DTW
5.98
X
5.99
X
6.05
5.76
X
6.97
5.17
5.20
4.89
4.58
4.43
4.54
5.22
5.28
5.24
5.62
5.66
5.37
2/4/95
GWEL
1,044.83
X
1,044.81
X
1,044.83
1,044.85
X
1,044.86
1,044.81
1,044.81
1,044.82
1,044.82
1,044.82
1,044.81
1,044.79
1,044.80
1,044.79
1,044.78
1,044.79
1,044.79
    Notes:
            All elevation data are based on top-of-casing elevations determined by leveling on 12/4/95; all elevations relative to mean sea level (msl) datum based on data
            provided by S&W.
            TOG EL=eIevation of top of (inner) monitoring well casing.
            DTW = depth to groundwater in monitoring well,  measured from top of casing.
            GW EL = elevation of piezometric surface.
            X - Groundwater elevation not measured due to presence of a hydrocarbon layer.
            Values in bold type indicate measurements known to be affected by the presence of a hydrocarbon layer.

-------
                                                                                                                                                P8
                                                                                                                                              (1044.86)
                       MW-D3
                     (1044.79)
           (1044.80) MW-D2
         (1044.79) MW-D6

         (1044.79) MW-D5


         (1 044.78) MW-D4
           (1044.79) MW-D1
  LEGEND

   +
SITE Program
Monitoring Well
SITE Program
Piezometer
  (1044.81piezometric
         Elevation on

   [77277] Iron Wall (Gate)
          Pea Gravel
                              MW-Fe2
                             (1044.82]
                                MW-Fe3 (1044.81)



                                  MW-U3 (1044.82)

                                  MW-U2 (1044.81)

                                  MW-U1 (1044.81)


                                  MFe1 (1044.82)
                                                           (1044.81
   P1
(1044.83)
                    Notes:
                    All elevations are relative to mean sea level (MSL) datum
                    and are +/- 0.01 foot accuracy.

                    (NM) - Piezometric elevation not measured due to presence
                    of hydrocarbon layer.
                                                                                              P6
                                                                                           (1044.85)
                      P5
                    (1044.83)
                                        General
                                      Groundwater
                                     Flow Direction
P2
NM
                                                                                               P4
                                                                                              (NM)
                                                                        pr
                                                                       (NM)
 SOURCE: Modified from PR01995
                                                                                  APPROXIMATE SCALE:  1" = 10'
Figure 2-28.  Piezometric elevations-December 1995.

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 2.2.1  BordenSite

 At the Borden site, an in-situ reactive wall was installed in
 June 1991 to treat groundwater contaminated with PCE
 and TCE. The source of the plume was located about 13.1
 feet below ground surface (bgs)  and 3.3 feet below the
 water table.  Maximum contaminant concentrations were
 about 250,000  and  43,000  ug/L  for TCE and PCE,
 respectively. The permeable wall was constructed about
 16 feet downgradient from the source.   The aquifer
 material was a medium to fine  sand, and the average
 groundwater flow velocity was about 0.3 foot per day
 (Gillham 1995;  1996).

 Samples were collected and analyzed over a  five-year
 monitoring period. The results indicate that PCE and TCE
 concentrations   decreased  consistently   while  the
 concentrations  of chloride  increased.  The  average
 maximum concentrations of PCE and TCE downstream of
 the  wall  were  about 10  percent  of the   influent
 concentration, indicating a substantial reduction within
 the wall. However, the concentrations of PCE and TCE hi
 the treated water were about three  orders of magnitude
 above site drinking water standards.  The results also
 indicated that cis- and trans-1,2-DCE were produced as a
 result of PCE and TCE degradation in the wall.  DCE
 isoniers were degraded as they passed through the wall,
 although effluent concentrations remained  above site
 drinking water standards.  No  VC  was detected in the
 samples, and no bacterial growth  was observed.  pH
 measurements were  also  taken,  the  results of which
 showed  little change in pH as  a  result of treatment
 (Gillham 1995; 1996). It is  suspected that the pH changes
 normally seen as a result of treatment were not  observed
 because of the buffering capacity of the carbonate sand
 used during  the treatment  process.  EH collected  core
 samples of the reactive iron after two years, and again after
 3.8 years, to evaluate precipitate formation. According to
 ETI, examination of samples of the reactive iron using x--
 ray  diffraction  and  scanning  electron  microscopy
techniques showed no metal precipitates on the iron.  (For
 more information, see O'Hannesin 1993.)

 2.2.2  California Semiconductor Facility

 Groundwater from the California  semiconductor facility
 contained TCE at concentrations ranging from 50 to 200
 ug/L, cDCE ranging from 450 to 1,000 ug/L, VC ranging
 from 100 to 500 ug/L, and Freon 113 ranging from 20 to 60
 ug/L. An above-ground pilot-scale demonstration reactor
containing 50 percent iron and 50 percent sand by weight
 was installed at the facility and operated for a period of 9
 months.  Although groundwater at the site  is highly
 mineralized, and precipitate formation was evident, it did
 not  appear to interfere with treatment of the  VOCs of
 concern (Yamane and others 1995; Szerdy and others
 1995; Focht, Vogan, and O'Hannesin 1996).

 Based on the results obtained from treatment in the
 reactor, a full-scale in-situ treatment wall was installed in
 December  1994.   The wall consisted  of 100 percent
 granular iron, was 3.9 feet thick, 39.4 feet long, and was
 situated vertically between depths of about 13 feet and
 39.4 feet bgs.  A layer of pea gravel, about 1-foot thick, was
 installed on both the upgradient and downgradient sides of
 the iron wall (Yamane and others 1995; Szerdy and others
 1995; Focht, Vogan, and O'Hannesin 1996).

 Since the system  was installed, no VOC concentrations
 exceeding MCLs have  been detected  in groundwater
 downgradient from the in-situ system (Yamane and others
 1995;  Szerdy and  others  1995; Focht, Vogan, and
 O'Hannesin 1996).

 2.2.3  Belfast, Northern Ireland Facility

 In 1995, a steel, cylindrical, in-situ reactive vessel was
 installed at a  depth of about 40 feet bgs at an industrial
 facility in Belfast, Ireland.  Groundwater at the facility
 reportedly contains TCE at concentrations as high as 300
 mg/L, along with lower concentrations of cDCE and vinyl
 chloride (ETI 1996c).

 The  in-situ reactive vessel measures 4 feet in diameter
 with a vertical thickness of iron measuring 16 feet. Two
 100-foot-long slurry walls were installed at the facility to
 divert groundwater to the reactive vessel.  Groundwater
 flows by gravity through the iron-laden reactive vessel and
 is discharged from a piped outlet on the downgradient side
 of vessel. The system was designed to allow about 5 days
 of residence time. The reactive vessel is equipped with a
 manhole to access the top of the iron zone in order  to
 scarify the iron surface if a buildup of precipitate should
 occur.  Total  cost of the system,  including the required
 design efforts, the slurry walls, the reactive vessel, and the
 iron was reportedly about $375,000 (ETI 1996c).

 Since installing the reactive vessel, TCE concentrations in
effluent groundwater have been reduced to less than 100
 Hg/L, and cDCE concentrations have been reduced to less
than  10 ug/L (ETI 1996c).
                                                   46

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                                             Section 3
                           Technology Applications Analysis
This section discusses the following topics regarding the
applicability  of  the  metal-enhanced  dechlorination
technology:  factors affecting technology performance,
site characteristics and support requirements, material
handling requirements, technology limitations, potential
regulatory., requirements, and  state  and  community
acceptance, This section is based on the results of the New
York site! .demonstration and  additional  information
provided by ETI and other sources.

3.1     Factors Affecting Performance

Factors potentially affecting the performance of the metal-
enhanced  dechlorination process include feed  waste
characteristics,  site  hydrogeology  and  maintenance
requirements.

3.1.1  Feed Waste Characteristics

Feed waste characteristics that may affect the performance
of the metal-enhanced dechlorination technology include
the types  and concentrations of organic and  inorganic
substances present in the groundwater to be treated, and
geochemical  parameters such  as pH  and possibly
temperature.                 .

Organic Compounds

According to ETI,  the  metal-enhanced dechlorination
technology has  successfully degraded many halogenated
VOCs. These compounds are PCE; TCE; cDCE; tDCE,
1,1-rdichlorpethene;  VC; TCA;  trichloromethane;  1,2-
dibromoethane;    1,2,3-trichloropropane;    1,2-
dichloropropane;  1,1-dichloroethane  and  Freon 113.
Although  the  degradation of  compounds  such  as
chloromethane,   dichloromethane, 1,2-dichloroethane,
and 1,4-dichlorobenzene is thermodynamically favorable,
these compounds have either not been observed to degrade
in the presence of iron or have not been studied in detail
(Gillham 1996; Focht, Vogan and O'Hannesin 1996).

The performance of the metal-enhanced dechlorination
technology is typically evaluated based on the half-lives of
the compounds that it  dechlorinates.  The half-life is
defined as the time required to degrade a compound to one-
half of its original concentration in the medium being
treated.  The  half-lives  of the different VOCs vary
depending on concentration and other site-specific factors.
Half-lives  using  treatment  by the  metal-enhanced
dechlorination  process generally appear to be less than
those reported for biological and other natural subsurface
abiological processes (Gillham 1996).

Although the reported half-lives for a particular compound
will vary,  half-lives generally tend to  increase with
decreasing degrees of chlorination.  This is particularly
evident when considering a single group of compounds,
such as chlorinated ethenes. PCE and TCE degrade at
reasonably similar rates; the rate is lower for DCE, and
lower yet for VC. This trend is consistent with reductive
dechlorination,  since  the most highly  chlorinated
compounds are the most oxidized and would be expected
to be the least stable under reducing conditions (Gillham
and O'Hannesin 1994; Gillham 1996).

Although many chlorinated VOCs can be degraded in the
presence of iron, further studies are required for many of
the VOCs to  evaluate the occurrence of toxic and
persistent  degradation  products.   In  addition,  the
degradation products generally degrade at -much lower
rates than the parent compound (ETI 1994; Fbcht, Vogan
and O'Hannesin 1996). Therefore, even though they occur
at much lower concentrations, degradation products may
be more critical than parent compounds with regard to
determining the required residence time in the design of
metal-enhanced dechlorination technology systems.
                                                   47

-------
 Inorganic Compounds

 Recent research has indicated that hexavalent chromium
 may be reduced by reactive iron.  At a recent installation
 involving a chlorinated VOC plume that also contained
 hexavalent chromium, EH observed that total chromium
 Was nondetectable downgradient from the system. Past
 studies by others have also indicated the iron's potential to
 reduce hexavalent chromium (Puls, Powell and Paul
 1995).  However, this potential application  of the
 technology has not been tested extensively.

 The  effect  of inorganic  compounds  on the  VOC
 degradation process may representthe greatest uncertainty
 with respect to the long-term,  low-maintenance operation
 of the in-situ metal-enhanced dechlorination technology.
 At the elevated pH levels induced by the dechlorination
 reaction, the Fe2* produced by the oxidation of the zero
 valent iron may precipitate as Fe(OH)2, depending on the
 DO concentration and provided that Eh is sufficiently low.
 Iron may also precipitate as FeCO3, depending on the
 carbonate  concentration of  the  influent groundwater.
 Carbonate  precipitates of calcium, magnesium, barium,
 and other metals may also form, particularly in the portion
 of the iron along the upgradient face of the wall.

 Excessive buildup of metal precipitates may limit the flow
 of groundwater through the treatment system. It is also
 possible that precipitates may block the iron surfaces
 available for reaction  causing a  reduction in the iron's
 reactive capacity over time, or decrease the dechlorination
 reaction  rate. Based  on the results of the New York
 demonstration,  ETI  estimates   that  formation  and
 deposition  of metal precipitates during treatment could
 cause about 4 to 7.5 percent of the original porosity in the
 iron to be lost annually (ETl 1996a). However, the amount
 of porosity loss is site specific;  ETI reports projected
 porosity losses ranging from 2 to 15 percent per year in
 studies  involving  water  from  other  sites.    The
 extrapolation of these estimates to field-scale systems
 depend on  the  kinetics of  precipitation  under field
 conditions (Focht, Vogan, and O'Hannesin 1996).

 Site- and waste-specific treatability studies are required to
 identify potential precipitates  and the rates at which they
 may form; possible effects on the reductive dechlorination
 rate and system hydraulics; and factors that may control
precipitate  formation.   O&M procedures may need  to
compensate for the formation  of precipitates during
treatment of highly mineralized water. Before proceeding
 with a full-scale remediation, it may be necessary to
 develop  operating  methods  to  prevent  precipitate
 formation or maintenance techniques to periodically
 remove precipitates once they form.

 3.1.2 Hydrogeologic Characteristics

 Site hydrogeology significantly affects the performance of
 the in-situ metal-enhanced dechlorination technology by
 controlling 1) the implementability of the technology; 2)
 selection of the type of system (continuous wall or funnel
 and gate); and 3) design parameters for the reactive iron
 wall.

 The technology's  implementability  is affected  by the
 depth to and saturated thickness of the aquifer.  Many
 chlorinated VOCs tend to sink when released in free phase
 to an aquifer, often causing dissolved-phase contaminants
 to be more concentrated in deeper portions of the aquifer.
 For this reason, the technology is most effective when it
 can  be installed to completely intercept flow over the
 entire saturated thickness of the aquifer. If possible, the
 base of the iron wall should be keyed into an underlying
 aquiclude to prevent untreated water from flowing beneath
 the wall.  As in any technology that requires trenching
 activities, the technology is more easily implemented at
 shallower depths (less than 50 feet). Also, if possible, the
 top of the wall should be high enough to prevent seasonal
 fluctuations in the water table from causing untreated
 water to flow over the wall. However, extension of the
 iron above the seasonal high water table may  not be
 practical for extremely shallow aquifers, as it is preferable
 to keep the top of the iron within the saturated zone to
 prevent exposure to  air and excessive oxidation.  ETI
 currently designs systems to cover as much of the vertical
 extent of the saturated zone as possible while still allowing
 about 3 feet above the iron for a dense soil cover to prevent
 excessive "rusting."

 For  these reasons,  shallow  unconsolidated  aquifers
 overlying dense clay or tight bedrock at depths less than 50
 feet  are more ideally suited for  this technology than
 bedrock aquifers or deep aquifers  in general. However,
methods   to  facilitate  deeper  applications  of  this
technology are currently being studied and at least one
deep installation (greater than 100 feet deep) was planned
for design at the time of this report (Appleton 1996).
                                                    48

-------
3.1.3 Operating Parameters

Based on information provided by the developer, several
operating parameters that may affect system performance
were identified. These parameters include (1) iron surface
area-to-groundwater volume ratio, (2) pH, (3) residence
time, and (4) temperature of the reactor and influent water.

Ratio  of  Iron  Surface  Area  to  Groundwater
(Solution) Volume

A precise quantitative correlation between the iron surface
area-to-water volume ratio on the dechlorination reaction
rate  has  not been  established.  Experimental results
indicate that the rate of dechlorination increases as the
ratio  of  iron  surface  area-to-groundwater  volume
increases. For this reason increasing the iron surface area
in contact with the water at any given time should increase
the dechlorination reaction rate, provided all other factors
remain constant (Gillham and O'Hannesin 1994; Gillham
1996). Based on this rationale, it appears that reductions in
the amount of iron  surface area,  possibly caused  by
precipitates  forming a  coating  on the  reactive  iron
granules, could increase contaminant half-lives.
pH
As previously discussed, the reactions which accompany
the dechlorination process cause pH to increase as water
dissociates to form H^ gas and hydrogen ions substitute for
chlorine atoms. This observation suggests that unusually
high or low influent pH in the influent groundwater may
affect the dechlorination reaction. However, the effects of
varying pH, and other geochemcial parameters (such as
DO  and Eh)  hi the influent  groundwater were  not
evaluated in detail  during the SITE demonstration, as
influent  groundwater  pH   was  relatively  constant
throughout the demonstration period.

Residence Time

Residence time is the time required for a "particle" of
groundwater to flow through a reactive iron treatment wall
in an in-situ installation, or through the iron layer in an
aboveground reactor. For any particular application, the
residence time of groundwater in the treatment medium
must be  sufficient to reduce  influent concentrations of
VOCs and potential dechlorination by-products to cleanup
standards.
To treat groundwater containing  several  chlorinated
VOCs having the potential to form multiple dechlorination
by-products, the total required residence time is calculated
as the sum of the estimated residence times required for
dechlorination of the compounds that have the longest
half-lives.  For example, the design of the in-situ wall at
the New York site was based on maximum projected half-
lives of about 0.2 hour for TCE, 3.7 hours for cDCE, and
1.2 hours for VC. ETI estimated a required residence time
of about 55 hours for the pilot-scale system, assuming that
cDCE would require the longest residence time of any of
the compounds (37 hours), due to the greater amount of
cDCE relative to the amount  of iron to be  used in the
system.   ETI conservatively  assumed that  no  VC
dechlorination would  occur until cDCE dechlorination
was complete.  The bench-scale studies indicated that the
other compounds suspected to be present (PCE, tDCE, and
TCA) would dechlorinate simultaneously with the other
compounds, not requiring additional residence tune (ETI
1994).

In an in-situ system, residence tune is controlled by the
groundwater flow  velocity and the thickness  of the
reactive  iron  wall.    The  appropriate thickness is
determined by dividing the required residence time by the
groundwater flow velocity (the natural flow velocity for
continuous walls, or an accelerated velocity projected for
a proposed funnel and gate system).  The wall must be
thick enough to allow adequate time for chlorinated VOCs
to be reduced from influent  concentrations to the
applicable water quality criteria, and must also  allow
sufficient time for dechlorination of any by-products. The
thickness  of  the   wall  should  also   incorporate  a
contingency factor to allow for seasonal fluctuations in
flow velocity.  For some applications, extra width may
also  be  appropriate  to  allow for  decreases  in the
performance of the upgradient portion of the iron due to
precipitate formation over time.

In an aboveground reactor, water typically flows vertically
through a reactive iron bed by gravity. The residence time
(volume of pore space in the reactive iron layer divided by
volumetric flow rate) is controlled by the hydraulic head
(which can be controlled by the influent pumping rate);
pore volume, hydraulic conductivity, and thickness of the
reactive iron layer; and the configuration of the effluent
piping. The results of a previous SITE demonstration of an
aboveground application of this technology suggested that
the same general  design criteria apply as for in-situ
systems; that is, the iron layer must be sufficiently thick to
                                                    49

-------
ai low adequate residence time for dechlorination of parent
compounds and potential dechlorination by-products.

Temperature

According to ETI, laboratory testing has indicated that
temperature affects the reaction rate for the dechlorination
of TCE, and presumably would affect reaction rates for
other compounds as well (EH 1996a). Data gathered at a
previous SITE Program demonstration of an aboveground
system  indicated  that a gradual  decline  in  reactor
temperature and the temperature of groundwater in the
reactor coincided with an apparent increase in the length of
time chlorinated VOCs persisted in the reactive iron bed.
However, data were insufficient to differentiate possible
temperature effects from  other factors that may have
affected system performance (EPA 1997).

During the New York demonstration, data indicated a
gradual lowering of groundwater temperature in the last 2
months of the demonstration. Unlike the demonstration of
the  aboveground  reactor, there  was no  measurable
increase  in the length   of time  required  for  TCE
dechlorination coincident with the temperature decline.
However, because TCE was generally below detectable
levels in the samples from the wells screened in the iron,
the  length   of  time  actually   required  for  TCE
dechlorination to occur is unknown.  For this reason, it is
possible that slight decreases in the TCE dechlorination
reaction rate occurred during the New York demonstration,
but were not detectable.

In general, in-situ remediation systems tend to be less
susceptible to temperature fluctuations than aboveground
systems. However, typical groundwater temperatures are
usually  less than the  ambient temperatures at which
laboratory treatability studies are  performed.   For
extremely shallow  aquifers, groundwater temperature
may fluctuate significantly, particularly in climates that
experience extreme ranges in seasonal temperature and
precipitation. If temperature does affect the reaction rate,
colder temperatures could increase the required residence
time.    For  these  reasons,  seasonal  groundwater
temperature should be considered in the system design;
design allowances (extra width)  may be necessary if
preconstruction studies indicate a potential for temperature
decrease to affect the dechlorination reaction rates.
3,7.4  Maintenance Requirements

The maintenance  requirements  for the  in-situ metal-
enhanced dechlorination  system summarized  in  this
section are based on observations of the pilot-scale system
used during the SITE demonstration; assumptions based
on the analytical data; results of previous applications of
the technology; and discussions with ETI personnel.

Metals precipitating from groundwater may accumulate
and physically block the pore spaces on the influent side of
the reactive iron medium, reducing flow. Also, metal
precipitates may coat the reactive iron surface, reducing
the surface area available for contact with contaminated
groundwater. Precipitate formation will vary depending
on a number of site-specific factors. According to ETI,
precipitates tend to concentrate in the first few inches on
the influent side of the reactive iron. However, because
relatively few in-situ systems have been operating for
more than 2 years (at the time of this report), knowledge of
long-term trends in and effects of precipitate formation is
primarily based on  extrapolations from bench  scale
studies  or short-term  observations from recent  field
applications.

Maintenance  procedures to counteract  the  effects of
precipitate formation for in-situ systems have not been
extensively tested in the field; however, ETI is currently
studying  methods  of  in-situ  chemical  or physical
treatment of the iron to remove precipitates. Possible
chemical methods  considered  include   dissolving
precipitates by introducing mild acids upgradient from the
wall; however, this technique currently does  not appear
feasible for most situations as the acid would also probably
react with the iron and cause excessive corrosion. Physical
techniques include scarifying or agitating the  upgradient
side of the iron wall. ETI has suggested the  use of soil
augers or mixing equipment at the interface between the
natural aquifer materials (or pea gravel, if present) and the
influent side of the iron to accomplish this task. However,
this technique has not yet been attempted at existing in-situ
installations and is untested under actual field conditions
at the time of this report. ETI estimates that some form of
maintenance  to remove precipitates  may typically be
required every 5 to  10  years  (Focht,  Vogan,  and
O'Hannesin 1996).

If maintenance techniques  are not successful, periodic
replacement of the iron may be necessary for long-term
(greater than 10 year) remedial programs.  For some
                                                    50

-------
applications, it also may be possible to allow a sufficient
thickness  contingency in  the  reactive  iron  wall to
compensate for reactivity losses caused by reductions in
the available reactive iron surface area.  However, this
would not necessarily alleviate problems associated with
significant reduction of the iron's hydraulic conductivity.

Biological growth in the reactive iron did not appear to be
a  significant problem during  the  New York in-situ
demonstration (PRC 1997).  Long term performance data
for in-situ systems under a wide range of conditions are
limited; therefore, potential operating problems caused by
long-term  biological growth have not  been  studied
extensively.

3.2   Site Characteristics and Support
       Requirements

Site-specific factors can impact the application of the in-
situ metal-enhanced  dechlorination  process, and these
factors  should  be  considered  before   selecting  the
technology for remediation of a specific site. Site-specific
factors addressed in this section are site access, area, and
preparation requirements; climate;  utility and supply
requirements; support systems; and personnel requirements.

According to ETI, both in-situ treatment wall installations
and aboveground treatment reactors are available  (see
Section 5, Technology Status, and Appendix A, Vendor's
Claims for the Technology). The support requirements of
these systems vary.   This  section presents  support
requirements based on the information collected for the in-
situ treatment system used at the New York demonstration
site.

3.2.1 Site Access, Area, and Preparation
       Requirements

In addition to the hydrogeologic conditions that determine
the technology's applicability  and design,  other  site
characteristics affect implementation of this technology.
The actual amount of space required for an in-situ system
depends  on the  required thickness and  length of the
reactive iron wall, and whether a continuous wall or funnel
and gate  system  are  used.   For  the New York
demonstration, the gate section comprised an area about
12feetby6.5 feet (includingthe3-foot-thick iron wall and
the adjacent pea  gravel sections) in plan. In addition, the
end sections comprising the funnel extended the length of
the system by 15 feet on each end. According to ETI, the
system captured a 24-foot-wide portion of the 300-foot-
wide plume. A full-scale funnel and gate system would
typically consist of several interspersed funnels and gates
or a continuous iron wall across the entire width of the
plume.  A system employing a continuous wall would
probably not be as thick as it would not employ flanking
sections of pea gravel; for example, ETI estimates that a 1 -
foot-thick wall may be adequate to  treat groundwater
under the  general conditions observed at the New York
site. (According to ETI, the effects of anisotropic flow are
less critical for continuous walls than for funnel and  gate
systems because the continuous walls are not expected to
accelerate groundwater flow velocity.)  In either case, the
length of the  system will depend on the  size of the
contaminant plume.   Sufficient  space must also be
available for monitoring wells upgradient and downgradient
from the system.

The site  must be  accessible to and have sufficient
operating  and  storage space for heavy construction
equipment. Excavating equipment is necessary to prepare
a subsurface trench.  For funnel and gate systems, a crane
equipped with a pile driver is necessary to install sheet
piling and to subsequently remove the sheet piling from
the upgradient and downgradient sides of the gate.  Access
for tractor trailers  (for delivery of  iron, construction
supplies, and equipment) is preferable. A front-end loader
may be needed to place the iron in the trench. Access for
a drill rig to install the wells for  system performance
monitoring will be  required, unless the  wells  are
constructed  as integral  parts of  a treatment  "cell."
Underground utilities crossing the path of the proposed
system may need to be relocated if present, arid overhead
space should be clear of utility lines, to allow cranes and
drill rigs to operate.  The wall may need to be constructed
around existing surface structures that are on site.

Soils  excavated at sites contaminated with chlorinated
VOCs may require management as a potentially hazardous
waste. For this reason, roll-off boxes to hold the soil, and
sufficient space near, but outside of the construction  area
for staging the boxes should  be available.  In addition, a
portable tank or tanker truck  should also be available for
funnel and gate installations to temporarily hold water
removed from the trench.

3.2.2  Climate Requirements

Because  the   in-situ  metal-enhanced  dechlorination
process is completely below grade and usually requires no
aboveground piping or utilities, the  system does not
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appear to be significantly affected by ambient weather
conditions. For this reason, the system can be installed and
operated in virtually any climatologic zone.  However,
variations in groundwater temperature may  need to be
considered in the system design (see Section 3.1.3.)

3.2.3  Utility and Supply Requirements

Existing on site sources of power and water may facilitate,
but are not required, for construction activities. After the
initial  construction  phase, the in-situ funnel and  gate
system at the New York site required no electrical power
or other utility support.

Supply requirements  specific  to the technology  may
include fresh iron medium to replace iron that has lost an
unacceptable  amount  of its  reactive capacity.   The
frequency at which iron may need to be replaced is highly
site-specific (see Section 3.1.4). Other supplies indirectly
related to the technology  include typical groundwater
sampling supplies that will be used for system monitoring.

3.2.4  Required Support Systems

No pretreatment of groundwater is necessary for in-situ
systems. As discussed in Section 1.3, potential users of
this technology must  consider the possibility that the
dechlorination of some multi-chlorinated compounds
such as PCE and TCE  may generate by-products such as
cDCE  and VC.    Properly  designed  systems allow
sufficientresidencetimetodechlorinate these compounds;
however, in-situ system designs may need to allow for
additional posttreatment "polishing" of system effluent in
the event that byproducts such as cDCE and VC persist. In
such cases, contingent systems such as air sparging/soil
vapor extraction (SVE) combined with carbon adsorption
of the effluent vapors may be appropriate.

S&W initially installed two PVC air sparging wells in the
downgradient pea gravel zone, as a contingency so that an
air sparging/SVE system could be rapidly constructed in
the event that persistent dechlorination by-products  such
as cDCE or VC were detected downgradient from the wall.
However, the in-situ  system appeared to consistently
reduce  concentrations of all  critical parameters  and
potential by-products  during the demonstration period.
For  this reason, posttreatment was  not implemented
during the demonstration.
3.2.5 Personnel Requirements

Personnel requirements for the system are minimal. Site
personnel must  collect  periodic samples  to evaluate
system performance. Also, personnel should periodically
inspect  the  system  for  general operating  condition.
Personnel should check water levels in the monitoring
wells and piezometers to ensure continuing flow through
the wall, and inspect the condition  of the  wells and
piezometers. Personnel should also inspect the condition
of the ground surface above the system and identify any
indications  of potential problems,  such  as  severe
subsidence or erosion.  If possible, representative core
samples  should  be periodically obtained  to evaluate
precipitate formation.   If support systems (such as air
sparging/SVE) are used, additional on-site personnel may
be required.

Personnel requirements for  long-term maintenance will
depend on the type of maintenance activities.  If soil
mixing, drilling, iron replacement, or  other  activities
requiring specialized heavy equipment will be performed,
trained equipment operators  will be required.

Personnel working with the  system at a hazardous waste
site should have completed the training requirements
under the Occupational Safety and Health Act (OSHA)
outlined in 29 CFR ง1910.120, which covers  hazardous
waste operations and emergency response. Personnel also
should participate in a medical monitoring program as
specified under OSHA.

3.3   Material Handling Requirements

Material  handling  requirements for the in-situ  metal-
enhanced dechlorination technology include those for the
soil and water removed from the excavation, the reactive
iron medium, and the pea gravel or well-sand used in the
construction of the system.  Groundwater removed by
trench dewatering will  probably contain chlorinated
VOCs. Also, soils excavated from below the water table in
the vicinity of a chlorinated VOC plume may have become
contaminated by contact with contaminated groundwater.
For this reason, soil and water generated by construction
activities may require handling, storage, and management
as hazardous wastes. Precautions may include availability
of lined, covered, roll-off boxes,  drums,   or other
receptacles for the soil; solvent-resistant storage tanks for
the water; and appropriate personal protective  equipment
(PPE)  for  handling materials  containing chlorinated
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VOCs. Soils from the vadose zone should be stockpiled on
site separately from soils excavated from below the water
table, to minimize  the amount of material  requiring
management as potentially hazardous waste.

Precautions required for the handling of the iron and pea
gravel include those normally  employed for nuisance
dusts, including the use of respiratory protection.

3.4   Technology Limitations

The in-situ metal-enhanced dechlorination technology is
limited  by the  ability of the reactive  iron to treat
wastestreams containing only certain chlorinated VOCs,
which limits the number of sites for which the technology
may be ideally suited.  Sites involving multiple types of
groundwater contaminants may not be ideally suited for
this technology.

Although recent studies by ETI and others have indicated
that  other  contaminants  (for  example,  hexavalent
chromium, uranium  and  some  other  metals;  some
brominated compounds;  and  some pesticides) may be
reduced by the technology, the reactive iron either cannot
reduce, or has not yet been extensively shown to reduce,
nonchlorinated organic compounds,  some chlorinated
VOCs (such  as  chloromethane, dichloromethane,  1,2-
dichloroethane, and 1,4-dichlorobenzene); some metals,
and other chlorinated organic  compounds  such  as
chlorinated phenols and most pesticides (ETI 1997; Focht,
Vogan, and O'Hannesin 1996). Aboveground systems or
other,  conventional ex-situ technologies can often be
modified  by  adding modular,  in-line pretreatment or
posttreatment components to treat multiple  types of
contaminants. However, auxiliary treatment systems that
are technically adaptable to the in-situ metal-enhanced
dechlorination process appear to be limited to conventional
in-situ technologies associated with VOC removal, such
as air sparging and SVE.

The  second   limitation  concerns  the reactive iron
medium's usable life before  its reactivity or  hydraulic
conductivity are significantly reduced by the formation of
metal precipitates. Information regarding the useful life
of the iron is limited because  no long-term (exceeding 5
years) performance data are currently  available.   As
discussed in  Section  1.3, the driving  force  of the
dechlorination reaction is the corrosion of iron,  or the
conversion of Feฐ to Fe2+.  According to ETI, the measured
corrosion rate of iron indicates that iron will persist for
several years to decades, depending on the concentration
of VOCs in the groundwater and the flow rate through the
iron (Focht,  Vogan, and O'Hannesin 1996).  However,
deposition of metal precipitates  on the reactive  iron
medium may adversely affect system hydraulics or block
the reactive surface area of the iron particles. Although
ETI is researching maintenance techniques to counteract
these effects, the proposed techniques are unproven under
representative full-scale field conditions at the time of this
report.

During the New York demonstration, no decline in the
system's ability to dechlorinate the target compounds was
noted, although the inorganic data and  geochemical
parameters suggested that metal precipitates were forming
in the iron.  However, in  a  previous  SITE  Program
demonstration of an  aboveground application of the
metal-enhanced  dechlorination  technology,  "parent"
chlorinated VOCs were observed to persist longer as the
demonstration progressed.  This effect was accompanied
by the appearance of low concentrations of dechlorination
by-products  (cDCE and VC) in the effluent.  Although
other factors may have contributed to the  decline in
performance, geochemical  data  indicated that metal
precipitates  were  forming,  and  subsequent  studies
performed by ETI confirmed that a hard precipitate layer
had formed in the upper (influent) portion of the reactive
iron bed (EPA 1997).

A third limitation of the technology is that passive systems
do  not necessarily remove the  contaminant source.
Although the system  may be able to treat all  of the
contaminated  groundwater  migrating  from   a  site,
contaminant sources upgradient from the system (such as
subsurface soils) may continue to release chlorinated
VOCs to groundwater until an aggressive remediation
scheme, such as removal, is enacted.  For this reason, to
achieve overall  permanent  remediation of a  site, the
technology may be most successful  if implemented in
conjunction with additional source reduction activities.

The fourth  limitation pertains to  the practicality of
implementing the technology at some sites. As for most
fully penetrating, in-situ containment/treatment systems,
the need for intrusive construction  activities  requires
significant  amounts  of open surface space,  possibly
precluding use of this technology at some sites. Also, the
limitations of trench construction technologies tend to
make fully penetrating systems best-suited for installations
shallower than 50 feet, and often less for some soil types.
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ETI has successfully used continuous excavation/backfill
technology to install reactive iron walls, eliminating many
of the time requirements, construction costs, and safety
concerns associated with conventional trenching activities,
and future applications may test the use of deep borings
and hydraulic  fracturing to  install systems at greater
depths (Appleton 1996). However, ETI's deepest existing
in-situ system is about 40 feet deep. Also, the technology
may be less effective  in aquifers lacking a suitable
underlying aquitard (for keying the base of the iron wall).

3.5   Potential Regulatory Requirements

This section discusses regulatory requirements pertinent
to using the in-situ metal-enhanced dechlorination process
at Superfund,  Resource Conservation  and Recovery
(RCRA) corrective action, and other cleanup sites.  The
regulations pertaining to applications of this technology
depend on site-specific conditions; therefore, this section
presents a general overview of the types of federal
regulations that may apply under various conditions. State
and  local  requirements  should  also  be  considered.
Because these  requirements  will vary, they are not
presented in detail in this section. Table 3-1 summarizes
the environmental  laws and associated  regulations
discussed in this section.

During the SITE demonstration  of the  in-situ metal-
enhanced  dechlorination process no groundwater  was
pumped from the affected aquifer to above the ground
surface. Therefore, many state and federal regulations
applicable to the pumping, treatment, and disposal or
discharge of contaminated groundwater were not relevant
to this particular application, nor would they be relevant
when this technology is used in similar fashion at other
sites.  If required, auxiliary posttreatment processes will
likely involve  additional regulatory requirements  that
would need  to be addressed.  This section focuses on
regulations applicable to  the in-situ  metal-enhanced
dechlorination technology, and briefly discusses regulations
that may apply if posttreatment is required.

3.5.1  Comprehensive Environmental
       Response, Compensation, and
       Liability Act

The  Comprehensive   Environmental  Response,
Compensation, and Liability Act (CERCLA), as amended
by SARA, authorizes the federal government to respond to
releases  of  hazardous   substances,  pollutants,  or
contaminants that  may   present  an  imminent  and
substantial danger to public health or welfare. CERCLA
pertains to the metal-enhanced dechlorination system by
governing the selection  and application of  remedial
technologies at Superfund sites.  Remedial alternatives
that significantly reduce the volume, toxicity, or mobility
of hazardous substances and provide long-term protection
are preferred.  Selected  remedies  must also  be cost-
effective, protective of human health and the environment,
and must comply with  environmental regulations to
protect human health and the environment during and after
remediation.

CERCLA requires identification and consideration of
environmental requirements  that are ARARs for site
remediation   before  implementation  of a  remedial
technology at a Superfund site.   Subject to specific
conditions,  EPA  allows   ARARs to  be  waived in
accordance with Section 121 of CERCLA. The conditions
under which an ARAR may be waived are (1) an activity
that does not achieve compliance with an ARAR, but is
part of a total remedial action that will achieve compliance
(such as a removal action), (2) an equivalent standard of
performance can be achieved without complying with an
ARAR, (3) compliance with an ARAR will  result hi a
greater risk to health and the environment than  will
noncompliance,   (4) compliance  with  an   ARAR is
technically impracticable,  (5) a state ARAR that has not
been applied consistently,  and (6) for fund-lead remedial
actions,  compliance  with the ARAR  will  result in
expenditures that are not justifiable in terms of protecting
public health or welfare, given the needs for funds at other
sites.  The justification for a waiver must  be clearly
demonstrated (EPA 1988a). Off-site remediations are not
eligible for ARAR waivers, and all applicable substantive
and administrative requirements must be met. Depending
on a  particular application,  posttreatment (secondary
treatment) such as air sparging/SVE may be used in
conjunction with the in-situ metal-enhanced dechlorination
technology, requiring air emissions and effluent discharge
either on or off site. CERCLA requires on-site discharges
to meet all substantive state and federal ARARs, such as
effluent standards.  Off-site discharges must comply not
only with substantive ARARs, but also state and federal
administrative ARARs, such as permitting, designed to
facilitate implementation of the substantive requirements.
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Table 3-1. Summary of Environmental Regulations
          Act/Authority    Applicability
                 Application to the In-Situ Metal-Enhanced
                 Dechlorination Technology	
                                                         Citation
          CERCLA
          RCRA
          CWA
          SDWA
          CAA
Cleanups at
Superfund sites
                 This program authorizes and regulates the   40 CFR part 300
                 cleanup of releases of hazardous
                 substances. It applies to all CERCLA site
                 cleanups and requires that other
                 environmental laws be considered as
                 appropriate to protect human health and the
                 environment.
                 RCRA regulates the transportation,
                 treatment, storage, and disposal of
                 hazardous wastes. RCRA also regulates
                 corrective actions at treatment, storage, and
                 disposal facilities.

                 NPDES requirements of CWA apply to both
                 Superfund and RCRA sites where treated
                 water is discharged to surface water bodies.
                 Pretreatment standards apply to discharges
                 toPOTWs. These regulations do not
                 typically apply to in-situ technologies.

                 Maximum contaminant levels and
                 contaminant level goals should be
                 considered when setting water cleanup
                 levels at RCRA corrective action and
                 Superfund sites.  Sole sources and
                 protected wellhead water sources would be
                 subject to their respective control programs.

Air emissions from If VOC emissions occur or hazardous air
stationary and     pollutants are of concern, these standards
mobile sources    may be applicable to ensure that use of this
                 technology does not degrade air quality.
                 State air program requirements also should
                 be considered.
Cleanups at
Superfund and
RCRA sites
Discharges to
surface water
bodies
Water discharges,
water reinjection,
and sole-source
aquifer and
wellhead
protection
40 CFR parts 260 to
270
40 CFR parts 122 to
125, part 403
          AEA and RCRA Mixed wastes
          OSHA
All remedial
actions
          NRC
All remedial
actions
40 CFR parts 141 to
149
                                                         40 CFR parts 50,
                                                         60, 61, and 70
                 AEA and RCRA requirements apply to the
                 treatment, storage, and disposal of mixed
                 waste containing both hazardous and
                 radioactive components.  OSWER and DOE
                 directives provide guidance for addressing
                 mixed waste.

                 OSHA regulates on-site construction
                 activities and the health and safety of
                 workers at hazardous waste sites.
                 Installation and operation of the metal-
                 enhanced dechlorination process at
                 Superfund or RCRA cleanup sites must
                 meet OSHA requirements.

                 These regulations include radiation
                 protection standards for NRC-licensed
                 activities.
                                                         AEA (10 CFR part
                                                         60) and RCRA (see
                                                         above)
29 CFR parts 1900
to 1926
10 CFR part 20
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3.5.2 Resource Conservation and
       Recovery Act

RCRA, as amended by the Hazardous and Solid Waste
Amendments of 1984, regulates management and disposal
of municipal and industrial solid wastes.  EPA and the
states implement and enforce RCRA and state regulations.
Some  of the RCRA  Subtitle C (hazardous  waste)
requirements under 40 CFR parts 264 and 265 may apply
at CERCLA sites  because remedial  actions generally
involve treatment, storage, or disposal of hazardous waste.
However, RCRA  requirements  may be waived for
CERCLA remediation sites, provided equivalent or more
stringent ARARs are followed.

Use  of  the  in-situ  metal-enhanced  dechlorination
technology may constitute "treatment" as defined under
RCRA regulations  in Title 40 of the Code  of Federal
Regulations  (40 CFR) 260.10.  Because treatment  of a
hazardous waste usually requires a permit under RCRA,
permitting requirements may apply if the technology is
used to treat a listed or characteristic hazardous waste.
Regulations in 40 CFR part 264, subpart X, which regulate
hazardous waste storage, treatment, and disposal in
miscellaneous units, may be  relevant to the  metal-
enhanced dechlorination process. Subpart X requires that
in order to obtain a permit for treatment in miscellaneous
units, an environmental assessment must be conducted to
demonstrate that the unit is designed, operated, and closed
in a manner that protects  human health  and  the
environment. Requirements in 40 CFR part 265, subpart Q
(Chemical,  Physical, and Biological Treatment), could
also  apply.  Subpart Q  includes requirements for waste
analysis and trial tests.  RCRA also contains special
standards for ignitable or reactive wastes,  incompatible
wastes, and special categories of waste (40 CFR parts 264
and 265, subpart B). These standards may apply to the in-
situ metal-enhanced dechlorination technology, depending
on the waste to be treated.

In the  event the in-situ metal-enhanced dechlorination
technology  is used  to treat  contaminated  liquids at
hazardous waste treatment, storage, and disposal facilities
as part of RCRA corrective actions, regulations in 40 CFR
part 264, subparts F and S may apply.  These regulations
include requirements for initiating and conducting RCRA
corrective actions, remediating groundwater, and operating
corrective action management units and temporary units
associated  with  remediation  operations.    In states
authorized   to  implement  RCRA,  additional  state
regulations more stringent or broader in scope than federal
requirements must also be addressed.

Most RCRA regulations affecting conventional treatment
technologies will not apply to the in-situ metal-enhanced
dechlorination  technology  because  once  installed,
properly designed and maintained systems generate no
residual waste. However, during installation activities, the
excavation of a trench and  removal of soil from the
saturated zone is required. Many chlorinated solvents are
RCRA  "F-listed" wastes;  therefore,  at  sites  where
groundwater is contaminated with these compounds, soils
removed from the saturated zone may also contain F-listed
contaminants and be classified as hazardous waste. If so,
these soils will require management, including storage,
shipment, and  disposal, following RCRA guidelines.
Active industrial facilities generating hazardous waste are
required to  have  designated  hazardous  waste  storage
areas, and most operate under 90-day storage permits.  A
facility's storage area could be used as a temporary storage
area for  contaminated  soils  generated  during the
installation of the in-situ metal-enhanced dechlorination
technology.    For nonactive facilities,  or those not
generating hazardous waste (as in the case of the site where
the New York demonstration occurred), a temporary
storage  area should be constructed on  site following
RCRA guidelines, and a  temporary hazardous waste
generator identification number should be obtained from
the regional EPA office. Guidelines for hazardous waste
storage are listed under 40 CFR parts 264 and 265. Also,
water  removed  from the  excavation  may  require
management as a hazardous waste. Tank storage of liquid
hazardous waste must  meet the requirements of 40 CFR
part 264 or 265, subpart J.

The  reactive iron may require  occasional physical or
chemical  treatment to  remove entrapped  solids  or
precipitates from the reactive iron medium.  Portions of
the influent side of the reactive iron may be periodically
replaced.  For in-situ  systems, methods for treating or
replacing the iron are still under evaluation at the time of
this report, and therefore the exact methods that will be
used are unknown at this time.  If these actions occur,
removed water, soil,  or reactive iron may be  RCRA
hazardous wastes,  and RCRA requirements for hazardous
waste disposal (see 40 CFR parts 264 and 265) may apply.
However, iron removed from the aboveground reactor
during  a previous SITE Program demonstration in New
Jersey was tested for residual contamination. The iron was
determined to be nonhazardous and  did not  require
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management as a RCRA  hazardous waste,  and was
subsequently sold as scrap metal.

Although not typically required, if secondary treatment is
used  in  conjunction with  the  in-situ  metal-enhanced
dechlorination process, additional RCRA regulations may
apply. If secondary treatment involves extraction and
treatment of  groundwater, and  the groundwater  is
classified as hazardous waste, the treated groundwater
must  meet  treatment  standards  under land disposal
restrictions (LDR) (40 CFR part 268) before reinjection or
placement  on  the  land  (for  example, in  a surface
impoundment).

RCRA parts 264 and 265,  subparts AA, BB, and CC
address air emissions from  hazardous waste treatment,
storage, and disposal facilities.  These regulations would
probably not apply directly to the in-situ metal-enhanced
dechlorination technology, but may apply to the overall
process if it incorporates secondary treatment, such as air
sparging/SVE.  Subpart AA  regulations apply to organic
emissions from process vents  on  certain  types  of
hazardous waste treatment units. Subpart BB regulations
apply to fugitive  emissions  (equipment leaks) from
hazardous waste treatment, storage, and disposal facilities
that treat waste containing organic concentrations of at
least 10 percent by weight.  Many organic air emissions
from hazardous waste tank systems, surface impoundments,
or containers will eventually  be subject to the air emission
regulations in 40 CFR parts 264 and 265, subpart CC.
Presently, EPA is deferring application of the Subpart CC
standards to waste management units used solely to treat
or store hazardous waste generated on site from remedial
activities required under RCRA  corrective  action  or
CERCLAresponse authorities (or similar state remediation
authorities).  Therefore, Subpart CC regulations may not
immediately impact implementation of the in-situ metal-
enhanced  dechlorination   technology  or  associated
secondary treatment technologies  used in remedial
applications. EPA may remove this deferral in the future.

3.5.3 Clean Water Act

The  Clean Water Act (CWA) governs  discharge  of
pollutants to navigable surface water bodies or publicly-
owned treatment works (POTW)  by providing for the
establishment  of federal,  state,  and local  discharge
standards.   Because  the   in-situ  metal-enhanced
dechlorination technology does not normally result  in
extraction and discharge of contaminated groundwater to
 surface water bodies or POTWs, the CWA would not
 typically apply to the normal operation and use of this
 technology.

 3.5.4  Safe Drinking Water Act

 The Safe Drinking Water Act (SDWA), as amended in
 1986, required EPA to establish regulations to protect
 human health from contaminants in drinking water. EPA
 has developed the following programs to achieve this
 objective: (1) a drinking water standards program, (2) an
 underground injection  control program,  and (3) sole-
 source aquifer and wellhead protection programs.

 SDWA primary (health-based) and secondary (aesthetic)
 MCLs generally apply as cleanup standards for water that
 is, or may be, used as drinking water. In some cases, such
 as when multiple contaminants are present, more stringent
 MCL goals may be  appropriate.    During the SITE
 demonstration, the in-situ metal-enhanced dechlorination
 process's performance  was evaluated to  determine its
 compliance with SDWA MCLs and NYSDEC standards
 for several critical VOCs.   The results indicated that
 effluent concentrations met MCLs during all months of
 testing after system performance stabilized; four out of 90
 critical  parameter  measurements  slightly  exceeded
NYSDEC limits in the same period.

 Water discharge through injection wells is regulated by the
 underground injection control program.  The technology
 does not require extraction and reinjection of groundwater;
therefore, regulations governing underground injection
programs would not typically apply to this technology.

The sole-source aquifer and wellhead protection programs
are designed to protect specific drinking water supply
 sources. If such a source is to be remediated using the in-
 situ metal-enhanced dechlorination technology, appropriate
program officials should be notified, and any potential
regulatory requirements should  be  identified.   State
groundwater  antidegradation  requirements and  water
quality standards (WQS) may also apply.

 3.5.5 Clean Air Act

The Clean Air Act (CAA), as amended in 1990, regulates
 stationary and mobile sources  of air emissions.  CAA
regulations are generally implemented through combined
federal, state, and local programs.  The CAA includes
pollutant-specific standards for major stationary sources
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that would not be ARARs for the in-situ metal-enhanced
dechlorination process, and would apply only if auxiliary
treatment (such as air sparging/SVE) were employed.
State  and  local  air  programs have been  delegated
significant  air quality regulatory responsibilities, and
some  have developed programs to regulate toxic air
pollutants (EPA 1989).   Therefore, state air programs
should be consulted regarding secondary treatment if used
in conjunction with this technology.

3.5.6 Mixed Waste Regulations

Use  of  the  in-situ  metal-enhanced  dechlorination
technology at sites with radioactive contamination might
involve treatment of mixed waste.  As defined by the
Atomic Energy Act (AEA) and RCRA, mixed waste
contains both radioactive and hazardous waste components.
Such waste is subject to the requirements of both acts.
However, when application of both AEA and RCRA
regulations results in a situation that is inconsistent with
the AEA  (for example,  an  increased  likelihood  of
radioactive exposure), AEA  requirements  supersede
RCRA  requirements (EPA   1988a).    OSWER,  in
conjunction with  the Nuclear  Regulatory Commission
(NRC), has  issued  several  directives  to  assist  in
identification, treatment,  and  disposal  of low-level
radioactive mixed waste.  Various  OSWER directives
include guidance on defining, identifying, and disposing
of  commercial,  mixed,  low-level radioactive,  and
hazardous waste  (EPA  1988b).   If the in-situ metal-
enhanced   dechlorination  process  is  used  to treat
groundwater  containing low-level mixed waste, these
directives should be considered,  especially regarding
contaminated soils excavated during installation. If high-
level mixed waste or transuranic mixed waste is treated,
internal  DOE  orders  should be  considered  when
developing a protective remedy (Department of Energy
[DOE]  1988).   The SDWA  and CWA also contain
standards for maximum allowable  radioactivity levels in
water supplies.

3.5.7 Occupational Safety and Health
       Act(OSHA)

OSHA regulations in 29 CFR parts  1900 through 1926 are
designed to  protect worker health and safety.  Both
Superfund and RCRA corrective actions must meet OSHA
requirements, particularly ง1910.120, Hazardous Waste
Operations and Emergency Response.  Part 1926, Safety
and Health Regulations for Construction, applies to any
on-site construction activities. For example, excavation of
the trench for placement of the reactive iron medium
during the demonstration was required to comply with
regulations in 29 CFR part 1926, subpart P. Any more
stringent state or local requirements must also be met. In
addition, health and safety plans for site  remediation
projects should address chemicals of concern and include
monitoring practices to ensure that worker health and
safety are maintained.

3.6   State and Community  Acceptance

State regulatory agencies will likely be involved in most
applications of the metal-enhanced dechlorination process
at hazardous waste sites.  Local community agencies and
citizen's groups are often also actively  involved hi
decisions regarding remedial alternatives.

Because  few  applications   of  the metal-enhanced
dechlorination technology have been completed, limited
information  is available to assess long-term state and
community acceptance. However, state and community
acceptance of this technology is generally expected to be
high, for several reasons:  (1) relative absence of intrusive
surface structures that restrict use of the treatment area; (2)
absence of noise  and air emissions;  (3) the  system  is
capable of  significantly reducing  concentrations of
hazardous substances in groundwater; and (4) the system
generates no residual wastes requiring off-site management
and does not transfer waste to other media.

NYSDEC oversees investigation and remedial activities at
the New York site. State personnel were actively involved
in the preparation of the work plan for the demonstration
of the pilot-scale funnel and gate system and monitored
system construction and performance. NYSDEC will also
be actively involved in planning for any full-scale systems
installed at the site. The role of states in selecting and
applying remedial technologies will likely increase in the
future  as state  environmental agencies  increasingly
assume many of the oversight and enforcement activities
previously performed at the EPA Regional level. For these
reasons, state regulatory requirements that are sometimes
more stringent than  federal requirements  may  take
precedence for some applications.  Also,  as  risk-based
closure and remediation become more commonplace, site-
specific cleanup goals determined by state agencies will
drive increasing  numbers  of remediation  projects,
including  applications involving the metal-enhanced
dechlorination technology.
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                                              Section 4
                                       Economic Analysis
This economic analysis presents cost estimates for using
an in-situ application of the metal-enhanced dechlorination
technology to treat contaminated groundwater. Costs are
presented  for two full-scale options:  1) a continuous,
reactive iron wall; and 2) a funnel and gate system.  The
cost estimates are based on systems designed to treat the
types and concentrations of chlorinated VOCs observed at
the New York demonstration site. The estimates are based
on data compiled during the SITE demonstration and from
additional information obtained from ETI, S&W, current
construction  cost estimating guidance,  independent
vendors, and SITE Program experience.

Past studies by ETI  have indicated that costs for  this
technology are highly variable and are dependent on the
types and concentrations of the contaminants present,
dimensions of the contaminant plume, site hydrogeology,
regulatory requirements, and other site-specific factors.
Estimates for total cost and cost per gallon of water treated
are also heavily influenced by assumptions regarding the
duration of the treatment program and the cumulative
volume treated. Furthermore, it is important to note that
the cost data presented in this report are partially based on
extrapolations from design and operating parameters for
the   pilot-scale  system  evaluated  during  the  SITE
demonstration. The purpose of the pilot-scale system was
to determine the optimal design and operating parameters
for  a  full-scale  system.   Differences  between  the
capabilities of New York pilot-scale system and full-scale
systems designed for optimal performance  at other sites
could cause  actual  costs to vary significantly from
estimates presented in this report.

Cost data are presented in terms of total cost and cost per
gallon of water treated to facilitate comparison of costs
with other treatment technologies. However, for passive
in-situ systems, the cumulative volume treated is limited
by the natural groundwater flow velocity,  and cost per
gallon may not always reflect the technology's overall
value. The in-situ metal-enhanced dechlorination process
combines the ability to remediate  groundwater with
features typically associated with containment systems;
under  optimal operating conditions,  the technology
prevents migration of contaminated groundwater toward
potential receptors by treating water passing through it.
The technology could be combined with source reduction
activities to enhance an overall remedial program at a site.

Due to the many factors that potentially affect the cost of
using this technology, several assumptions were necessary
to prepare the economic analysis.  Several of the most
significant of these assumptions are: (1) a continuous,
reactive iron wall is  assumed to be best-suited for this
particular application; however, cost estimates for a funnel
and gate system are also provided for comparison; (2) the
system will treat water contaminated with TCE, cDCE,
and VC at  concentrations  observed during the  SITE
demonstration; and (3) the system will treat groundwater
for 20 years.  (This assumption requires extrapolation of
some SITE demonstration data  to the longer operating
period.)

The 20-year timeframe was selected for consistency with
cost evaluations of other  innovative  technologies
evaluated by the EPA SITE Program, and because it
facilitates comparison to typical costs associated with
conventional, long-term remedial options. The timeframe
does not reflect any estimate of the actual time required to
remediate groundwater at the New York site.

  This  section  summarizes site-specific  factors  that
influence costs, presents assumptions used in this analysis,
discusses estimated costs, and presents conclusions of the
economic analysis.   Tables 4-1  and 4-2  present  the
estimated costs generated from this analysis. Costs have
been distributed among 12 categories applicable to typical
cleanup activities at Superfund and RCRA sites (Evans
1990). Costs are presented hi 1996 dollars, are rounded to
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Table 4-1.  Estimated Costs Associated with the Metal-Enhanced Dechlorination Technology: Continuous Wall System
                           Cost Category
Cost
Total Cost
                Site Preparation11
                       Administrative                    $15,700
                       Treatability study                  20,000
                       System design                    10,000
                       Excavation and backfill            152,500
                       Monitoring wells                     6,100
                       Soil and Water Disposal            64,300
                Permitting and Regulatory"
                Mobilization and Startup"
                Capital Equipment"
                       Reactive Iron                    135,000
                       Sampling Equipment                 8,000
                Demobilization"
                Total Estimated Fixed Costs
                Labor (Sampling and Routine O&M)C
                Supplies0
                       PPE                               $300
                       Carbon Canisters                     700
                       Sampling equipment                 1,000
                Utilities0
                Effluent Treatment and Disposal0
                Residual Waste Handling0
                Analytical Services0
                Equipment Maintenance0'*
                Total Estimated Variable (Annual) Costs
                Total Estimated Fixed and Variable
                Costs After 20 Years8
                Costs per  1,000 gallons treated'
                Costs per  gallon treated1     	
             $268,600
             Notes:
                 4,000
               40,000
              143,000
              $11,000
             $466,600
                $5,500
                 2,000
                    0
                    0
                    0
                 9,300
                 4,100
              $20,900

             $884,600
                  $18.02
                   $0.018
                    AH costs presented in 1996 dollars.
                    *      Costs estimated based on data from SITE demonstration and other sources.
                    "      Fixed costs.
                    0      Variable costs, presented as annual total.
                    d      Annual total prorated from expense incurred at 7-year intervals.
                    •      Total costs after 20 years of operations; all annual costs multiplied by 20, plus
                           total fixed costs.
                    f      Total of 49.1 million gallons of groundwater treated.
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Table 4-2. Estimated Costs Associated with the Metal-Enhanced Dechlorination Technology: Funnel and Gate System
                                Cost Category
  Cost
                    Site Preparation"
                           Administrative                    $15,700
                           Treatability study                  20,000
                           System design                     10,000
                           Funnel and Gate Construction      266,000
                           Monitoring wells                    6,100
                           Soil and Water Disposal            64,300
                    Permitting and Regulatoryb
                    Mobilization and Startup"
                    Capital Equipment"
                           Reactive Iron                     135,000
                           Sampling Equipment                8,000
                    Demobilization"
                    Total Estimated Fixed Costs
                    Labor (Sampling and Routine O&M)C
                    Supplies0
                           PPE
                           Carbon Canisters
                           Sampling equipment
                    Utilities0
                    Effluent Treatment and Disposal0
                    Residual Waste Handling0
                    Analytical Services0
                    Equipment Maintenance0'4
                    Total Estimated Variable (Annual) Costs
                    Total Estimated Fixed and Variable
                    Costs After 20 Years e

                    Costs per 1,000 gallons treated'
                    Costs per gallon treated'	
$300
  700
1,000
                 Notes:
Total Cost
               $382.100
                  4,000
                 32,500
                143,000
                $11.000
               $572,600
                 $5,500
                  2,000
                      0
                      0
                      0
                  9,300
                  2,700
               $19,500

              $962,600
                   $19.60
                    $0.020
                        All costs presented in 1996 dollars.
                        a      Costs estimated based on data from SITE demonstration and other sources.
                        "      Fixed costs.
                        0      Variable costs, presented as annual total.
                        d      Annual total prorated from expense incurred at 7-year intervals.
                        e      Total costs after 20 years of operations; all annual costs multiplied by 20, plus
                               total fixed costs.
                        f       Total of 49.1 million gallons of groundwater treated.
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the nearest 100 dollars, and are considered to be order-of-
magnitude estimates.

4.1    Factors Affecting Costs

Costs for implementing this technology are significantly
affected by site-specific factors, including site regulatory
status, waste-related  factors,  and site  features.   The
regulatory status of the site typically depends on the type
of waste management activities that occurred on site, the
relative risk to nearby  populations  and  ecological
receptors, the state in which the site is located, and other
factors.  The site's regulatory status affects  costs by
mandating ARAR's  and remediation goals that may affect
the system  design parameters and duration of  the
remediation project. Certain types of sites may have more
stringent monitoring requirements than others, depending
on regulatory status.

Waste-related factors affecting costs include contaminant
plume size  and  geometry;  contaminant types  and
concentrations, andregulatory agency-designated treatment
goals. Plumes that cover extensive areas will require
longer walls or more  funnels and gates to achieve
hydraulic control, and may take longer to pass through the
treatment system.  Larger contaminant masses (plume
volume times contaminant concentration) require greater
amounts of reactive iron.

The  contaminant  types  and concentrations  in  the
groundwater determine contaminant half-lives.   The
required residence time in the iron, which determines the
appropriate width for the reactive  iron  zone and  affects
capital equipment costs and construction costs, is based on
the contaminant half-lives, the remediation goals, and the
groundwater flow velocity. The types of contaminants and
the remediation goals may also determine the need for
auxiliary  in-situ treatment systems  and will influence
performance monitoring requirements.

Site features affecting costs  include site hydrogeology
(geologic  features  and  groundwater  flow  rates),
groundwater chemistry  (for example, concentrations of
inorganic substances), and  site location  and physical
characteristics. Hydrogeologic conditions are significant
factors in  determining  the  applicability  and  design
parameters, and thus the costs, of in-situ applications of
the metal-enhaaced dechlorination process, and should be
thoroughly defined  before applying this technology. The
saturated thickness  determines the required height of the
reactive  iron wall.   The  groundwater flow velocity
determines the thickness of the iron wall required to allow
sufficient residence time for dechlorination  to  occur.
These  factors  (along with  the  dimensions  of the
contaminant plume) determine the necessary volume of
iron and trench dimensions. The depth to water and the
depth to the uppermost underlying aquitard determine the
depth of the installation and the type of construction
technology that will be employed.  All of these factors
affect capital equipment costs and site preparation costs.
Also, since this is a passive technology, the groundwater
flow  velocity  and  saturated  thickness  will  control
volumetric flow  through the  system, influencing the
duration  of the remediation project and time-ielated
variable costs, such as analytical and maintenance costs.

Groundwater chemistry can  also  affect costs.   High
concentrations  of dissolved  inorganic substances in
influent  groundwater may result in precipitation of
compounds such as calcium carbonate, particularly on the
upper/influent side of the iron, requiring more frequent
maintenance.

Site  location  and   physical  features   will  impact
mobilization, demobilization,  and site preparation costs.
Mobilization and demobilization costs are affected by the
relative distances that system materials must travel to the
site. Sites requiring extensive surficial preparation (such
as constructing access roads, clearing large trees, working
around or demolishing structures) or restoration activities
will also incur higher costs.

Depending on the type of system installed, the availability
of  existing  electrical power and  water supplies  may
facilitate construction activities.  However, unlike many
conventional technologies, system operation typically
requires  no utilities.   For these reasons, utilities are
typically not a significant factor affecting costs for this
technology.

4.2   Assumptions Used in Performing
       the Economic  Analysis

This section summarizes major assumptions regarding
site-specific  factors  and  equipment  and  operating
parameters  used  in  this economic  analysis.  Certain
assumptions were made to  account for variable site and
waste  parameters.   Other  assumptions were made  to
simplify cost estimating for situations that actually would
require complex  engineering or financial functions.  In
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general, most system operating issues and assumptions are
based  on information provided  by ETI,  S&W,  and
observations made during the SITE demonstration. Cost
figures are established from information provided by ETI
(ETI 1996b; 1996d), S&W (1994), current environmental
restoration cost guidance (R.S. Means [Means] 1996), and
SITE Program experience.

Assumptions regarding site- and waste-related factors
include the following:

  •    The site is a Superfund site, located in the north-
       eastern U.S.

       Site groundwater is contaminated with TCE,
       cDCE, and VC at maximum concentrations of
       about 300 jxg/L, 500  ug/L, and 100 ug/L, respec-
       tively.

       The cleanup goals are federal MCL requirements
       of 5 ug/L for both TCE and cDCE, and 2 ug/L for
       VC.

  •    The site is located in  a rural area, but is easily ac-
       cessible to standard (wheel-mounted) heavy equip-
       ment.

  •    Contaminated water is located in a shallow aqui-
       fer that overlies a dense, silty clay aquitard at a
       depth of 15 feet bgs.

  •    The aquifer is a moderately permeable sand and
       gravel aquifer, with a natural horizontal  flow ve-
       locity of 0.75  foot per day. The seasonal saturated
       thickness varies from about 10 to 12 feet.

  •    The groundwater  contaminant plume is  300 feet
       wide.

  •    The site has no existing structures requiring demo-
       lition and does not require extensive clearing.
       There are  no existing utilities on site that require
       relocation or restrict operation of heavy equipment
       such as excavators, cranes, or drill rigs.

  •    Typical naturally occurring inorganic substances
       are present in site groundwater, but do not result
       in excessively rapid precipitate buildup.
Assumptions regarding treatment system  design and
operating parameters include the following:

  •    A continuous iron wall will be used for this appli-
       cation.  However, costs for an alternative three-
       gate runnel and gate system are presented for com-
       parison.

  •    The hydraulic conductivity of the iron is assumed
       to be 142 feet per day; the porosity is assumed to
       be 0.4.  The groundwater flow velocity through
       the continuous iron wall is assumed to  be about
       the same as for the natural aquifer materials, 0.75
       foot per day. Based on these parameters, the plume
       dimensions, and the saturated thickness, the wall
       will be 300 feet long, 12.5 feet high, and 1.0 foot
       thick, and will require about 337.5  tons of iron
       (ETI 1996b; 1996d).

  •    If a funnel and gate system is used, the system
       would consist of three gates, each about 20 feet
       wide. Total system length (including sheet pile
       funnels) would be 440 feet. According to ETI, run-
       nel and gate systems significantly accelerate flow
       velocities and would treat about the same volume
       of water and the same contaminant mass flux as
       the continuous wall.  For this reason, ETI estimates
       that the combined total mass of iron used for the 3
       gates would be the same as the minimum recom-
       mended for the continuous wall (about 337.5 tons),
       resulting in each gate having a 5-foot-thick iron
       wall (ETI 1996d).

       The minimum volume of groundwater  that will
       pass through the continuous wall or through the
       funnel and gate system during the remediation
       project is assumed to be 49.1 million gallons, as-
       suming the flow velocity, porosity, and hydraulic
       conductivity remain constant.

  •    ETI will provide a representative as an on-site con-
       sultant for key phases of the construction.

  •    The system continually treats groundwater for 20
       years. No downtime is required for periodic main-
       tenance.

  •    The system continues to achieve cleanup  goals
       over the remediation period.  For this reason, and
       because the treatment system operates in-situ, there
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       are no additional effluent management require-
       ments, such as air sparging.

  •    After construction, the treatment system operates
       without the constant attention of an operator. Rou-
       tine labor requirements consist of monthly sam-
       pling, measurement of water levels, inspection of
       the monitoring wells and ground surface above the
       system, and mowing the area above the system.

  •    Periodic  maintenance may consist of using soil
       mixing equipment to agitate the upgradient side
       of the iron wall every 5 to 7 years. However, the
       effectiveness and feasibility of this  technique is
       undocumented at this time.

  •    All system components are below grade, so no
       anti freezing measures are required.

  •    All equipment and supplies are mobilized from
       within 500 miles of the site, or less.

  •    Monthly samples of upgradient (influent) and
       downgradient (effluent) groundwater will be re-
       quired for the first 6 months after installation. After
       this period, quarterly samples will be required, for
       20 years.

Depreciation is  not  considered in  order  to simplify
presenting  the costs  of this analysis.Most  groundwater
remediation projects are long-term in nature, and usually a
net  present  worth  analysis  is  performed  for  cost
comparisons.   However, the variable costs for  this
technology  are  relatively low,   and  no other  system
configurations or technologies  are  presented  in  this
analysis for comparison. For these reasons, annual costs
arc not adjusted  for inflation, and no net present value is
calculated.

4.3   Cost Categories

Table 4-1 presents cost breakdowns for each of the 12 cost
categories  for the continuous wall.   Data  have  been
presented  for the  following  cost categories:  (1) site
preparation, (2) permitting and regulatory, (3) mobilization
and startup, (4) capital equipment, (5) labor, (6) supplies,
(7) utilities, (8) effluent treatment  and disposal, (9) residual
waste  shipping  and handling,  (10) analytical services,
(11) equipment maintenance, and (12) site demobilization.
Because costs for a funnel and gate system would probably
be different than those associated with a continuous wall,
Table 4-2 presents the costs for a three-gate funnel and gate
system treating the same size  and type of contaminant
plume  as  the  continuous  wall.   Each of the  12 cost
categories are discussed below.

4.3.1 Site Preparation  Costs

Site preparation costs include administration costs, costs
for conducting a bench-scale treatability study, conducting
engineering design activities, and preparing the treatment
area.  Site preparation also includes costs associated with
constructing the continuous wall or funnel and gate system
and making the system operational, with the exception of
mobilization charges for specialized heavy construction
equipment (see Section 4.3.3)  and  the cost of the iron
medium (see Section 4.3.4).

Administrative costs include  costs  for legal searches,
contracting,  and  general  project  planning activities.
Administrative costs are highly site-specific;  for  this
estimate, administrative costs are assumed to be $12,500,
or about 200 hours of technical staff labor at $50 per hour
and 100 hours of administrative staff labor at $25 per hour
(Means 1996). Also, ETI typically charges a site license
fee equal to 15 percent of the iron costs (see Section 4.3.4).
For either the full-scale continuous wall or funnel and gate
systems, ETI's site license  fee is estimated to be about
$3,200.

According to ETI and S&W, a phased treatability study
will take between 2 to 4 months to complete (see Section 5
for a discussion of the four phases used to  implement the
technology). Treatability study costs include expenses for
column  tests  and  labor.   According  to  ETI,   typical
analytical laboratory costs for column tests for a project
similar to the one at this site will be about $15,000.  The
labor  for the  treatability study will be  about  $5,000,
inclusive of 100 hours at an average rate of $50 per hour.
The total cost of a treatability study will be about $20,000
(EPA 1997).

After the study and a site assessment, ETI will assist in the
design of an optimal system configuration for a particular
site. The total system design costs are estimated to be about
$10,000.  This cost includes about  130 labor hours at an
average rate of $75 per hour (Means 1996). This estimate
assumes  that site  hydrogeology  has  already been
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thoroughly characterized, and no additional hydrogeologic
data will be required. If additional hydrogeologic studies
are required, design costs could be higher.

Treatment area preparation costs depend on the type of
system used. ETI estimates that for a site having the same
waste and site features as the New York site, a continuous
reactive iron wall may be the most cost effective type of
system (ETI 1996d).  Costs for a continuous wall include
excavating a trench,  backfilling  it with reactive iron,
disposing  of  the  displaced  soil,   and  installing  a
groundwater monitoring system.   This estimate assumes
that a continuous trenching/backfill technique will be used
to excavate the trench and emplace the iron, eliminating
the need for shoring.  Before excavating the trench, soil
from above the saturated zone (this estimate assumes the
upper 3  feet of native soil) can be  excavated with a
conventional backhoe, stockpiled on site, and eventually
replaced to form a cover over the iron,  at an assumed cost
of about $2,000 (Means 1996).

After the top 3 feet of soil are removed, the trench will be
extended down to the top of the underlying  clay layer, in
this case assumed to be 15 feet below ground surface, using
continuous  trenching/backfilling  equipment.     The
equipment will continuously excavate and  backfill each
section of trench with iron, up to about 2.5 feet below
grade, continuing until the 300-foot  long iron wall is
completed. According to ETI, at this depth, it is possible to
construct about 100 to 200 lineal feet of reactive iron wall
per day using this technique.  Costs for the excavation/
backfill  equipment and operator are estimated to be
$150,500, not including mobilization (see Section 4.3.3).
(This figure includes costs for transferring soil to roll-off
boxes as  the  trench  is  excavated.)    Total  trench
construction  costs are  estimated to  be $152,500, not
including the costs of the reactive iron (see Section 4.3.4)
(Means 1996; ETI 1996d).

After all of the iron is emplaced and settled, the top of the
wall will be about 3 feet bgs.  The stockpiled native soil
from the upper part of the excavation, which will not have
contacted contaminated groundwater,  will be used to fill
the upper part of the trench. Soil excavated from the lower
portion of the trench (below the water table) will have
contacted groundwater contaminated with RCRA F-listed
solvents and may require management as  a  hazardous
waste.  This cost estimate assumes that the soil will be
loaded  into roll-off containers, stored  on site pending
characterization, and shipped offsite and disposed of as a
hazardous waste.  Based on the dimensions of the trench
for the continuous wall (and the volume of soil displaced
by monitoring well construction), about 140 cubic yards of
soil will require disposal.  Assuming a disposal cost of
$400 per cubic yard (landfill disposal), transport costs of
$3.30 per mile for each roll-off container, characterization
and manifesting fees of $5000, and disposal at a location
100-miles from the  site, total  costs for  managing this
material are estimated to be about $62,300. Actual costs
for waste disposal are highly site specific, and may vary
substantially from this estimate, particularly if the soil
requires incineration (Means 1996).

 Alternatively, if a funnel and gate configuration is used,
ETI  estimates  that a three-gate, 440-foot-long system
would capture the 300-foot-wide plume. Each gate would
be constructed using the same general techniques used for
the pilot-scale system demonstrated at the New York site
(see Section 1). Site preparation costs would include costs
for excavating and backfilling the three 20-foot-wide gates
with a reactive iron  section bordered by  pea gravel and
installing the sheet-piling to form the continuous funnel.
ETI estimates construction and material costs (including
sheet piling, but not including the reactive iron) to be
$264,000 for this system (ETI 1996d).  For estimating
purposes, topsoil removal and replacement, soil disposal,
and all  other site preparation costs are assumed to be the
same as for the continuous  wall.

A groundwater monitoring system will  be required  to
monitor system performance. For a continuous wall, this
estimate assumes that  the system will  require  a well
spacing of no more than 50 feet along the downgradient
side of the wall, to ensure that all sections of the wall are
performing adequately.  Three upgradient wells will also
be installed to  allow  determination  of the  system's
removal efficiency. Installation and development of nine,
 15-foot-deep PVC monitoring wells with locking caps and
flush-mounted protective casings will be required. The
assumed cost for these wells is $45 per foot (including drill
rig mobilization from within 50 miles of the site), for a total
cost of about $6,100. Auger cuttings (about 2 cubic yards)
will be  disposed of with the material from the trench; costs
for this were included  in the waste  disposal costs
previously discussed.

For a funnel and gate system, this estimate assumes that
one upgradient well and two downgradient wells would be
constructed in the pea gravel zones at each gate. It may be
possible to install these wells at the time of construction,
eliminating the need for drilling. However, at a minimum,
the wells will require bracing and completion methods
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similar to those used during the SITE demonstration, so for
estimating purposes, construction costs for these wells are
also assumed to be $45 per lineal foot,,for a total of $6,100.

Water from monitoring well development (or from trench
dewatering activities for a funnel and gate system) will
contain site contaminants. This estimate assumes that the
water can be passed through a carbon filter and discharged
to the ground surface upgradient from the system.  Costs
for this method of disposal are assumed to be about $2,000,
including the cost of carbon canisters and labor.

All system components will be completed below grade.
The wells will have locking inner caps. For this reason, no
costs for additional security (fences) will be incurred.

For a continuous iron wall, total site preparation costs are
estimated to be $268,600; for a funnel and gate system, site
preparation costs are assumed to be $382,100.

4.3.2  Permitting and Regulatory Costs

Permitting and regulatory costs are highly site-specific and
will  depend  on whether treatment  is performed at  a
Superfund  or a RCRA corrective action site; wellhead
protection area restrictions; and other factors. Superfund
site remedial actions must be consistent with ARARs of
environmental laws, ordinances, regulations, and statutes,
including federal, state, and local standards and criteria.
Remediation at RCRA corrective  action sites  requires
additional monitoring  and record  keeping, which  can
increase the base regulatory costs.

The  cost  of all  permits is  based  on  the  effluent
characteristics and related receiving water requirements.
For this analysis,  groundwater is  not  extracted before
treatment, so the costs assume that no permit for discharge
of treated effluent to the aquifer will be required.  (This
assumption is based on ETI's experience at several full-
scale installations  in  the U.S.).  For  this reason, this
estimate assumes that total permitting and regulatory costs
are minimal; about $4,000. This includes 50 hours of labor
at $75 per hour, and $250 for miscellaneous expenses such
as fees and reproduction costs.

4.3.3  Mobilization and Startup Costs

Mobilization  and startup costs consist of mobilizing the
construction equipment and materials and delivering the
reactive iron.  However, unlike conventional aboveground
systems, no  additional  assembly charges are incurred
beyond the construction costs described in Section 4.3.1.
The technology requires no electrical power, water supply,
or  other  utilities.   For  in-situ applications  of this
technology, mobilization and startup costs are assumed to
consist  solely  of equipment  mobilization  charges.
Mobilization costs will vary depending on the location of
the site in relation to suppliers.  Based on information
provided  by ETI,  mobilization  of  the  specialized
construction equipment for a continuous wall (to a site, in
the northeastern U.S.) is assumed to be $40,000.  For a
funnel  and  gate  system,  equipment  mobilization  is
assumed to be $32,500.

For the  site where the demonstration of the aboveground
reactor occurred, which was also in the northeastern U.S.,
ETI estimated that iron transportation costs would be
about $75 per ton, or about 14 percent of the cost of the iron
(EPA 1997).  ETI's current estimates for the cost of the
iron include  delivery costs (see  Section 4.3.4); for this
reason,  iron delivery charges are not listed as a separate
item in Tables 4-1 and 4-2. However, costs for the iron will
be  influenced by the site's location in relation to  the
supplier, the distance the iron must be transported to the
site, the mode of packaging (bulk, drums, or 1-cubic yard
"totes"), and the mode of transportation.  For this reason,
iron costs may vary on a site-specific basis.

4.3.4  Capital Equipment Costs

Capital equipment costs for this analysis include the cost of
the reactive iron and groundwater monitoring equipment.
Costs for other materials (monitoring wells, sheet piling
funnels, etc.) were previously discussed in Section 4.3.1
and are not considered to be capital equipment costs for
this estimate.

ETI configures the complete treatment system based on
site-specific conditions.  According to ETI, current costs
for the reactive iron, including delivery to a site in  the
northeastern U.S., are about $400 per ton, assuming truck
delivery of iron in bulk form. (However, costs may vary on
a site-specific basis.) ETI estimates that the typical iron
density after  settling is about 180 pounds per cubic foot
(0.09 ton per cubic foot).  Based on this estimate,  the
3,750-cubic-foot continuous wall will require about 337.5
tons of reactive iron, resulting in a total capital equipment
cost of about $135,000.  According to ETI, the same
amount of iron would be required for a funnel and gate
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system, as the system would treat the same volume of
contaminated groundwater as the continuous wall.

For either system, equipment that will be required to
monitor the technology's performance includes a low-
flow sampling pump and meters to measure pH, Eh, and
other field parameters. Because this is a long-term project
purchasing  these items  will probably  be more cost
effective than renting them. This estimate assumes that
these items will cost about $8,000.

Total capital equipment costs are estimated to be $ 143,000
for either the continuous wall  or the funnel and gate
system.

4.3.5  Labor Costs

Once the system is functioning, it is assumed to operate
unattended and continuously except during routine O&M,
monitoring, and sampling activities.

Routine O&M will generally consist of mowing the area
over and  around the  treatment  system (to  prevent
establishment of deep-rooted plants arid maintain access to
the monitoring wells), inspecting the area for excessive
subsidence or erosion, and inspecting the condition of the
monitoring wells. Mowing could be contracted out at $50
per job, and would be required four times per year for an
annual cost of $200.

Inspection activities could be performed concurrently with
 sampling. This cost estimate assumes that samples will be
 collected monthly for the first 6 months after installation,
 and then quarterly for the duration of the project.  More
 frequent monitoring is recommended immediately after
 installation to ensure that the system  is  performing
 according to design.  This cost estimate assumes that all
 sampling and analytical tasks  will be  performed  by
 independent contractors and labor costs for sampling are
 $45 per hour (Means 1996). During each sampling event,
 sampling  personnel  should  also inspect the general
 condition of the treatment system area and the condition of
 the  monitoring wells. Routine monitoring and sampling
 activities are  assumed to take about 16 hours per event,
 assuming measurement of water levels and collection of
 groundwater  samples   from  nine  monitoring  wells,
 laboratory  coordination, and sample shipment.   Data
 interpretation and reporting will take an additional 12
 hours per event. Based on these estimates total sampling-
 related labor costs are $1,260 per sampling event. For a
20-year remediation  project,  estimated sampling labor
costs prorate to about $5,300 per year.

Total routine O&M and sampling costs are estimated to be
$5,500 per year.  Laboratory analytical costs are presented
in Section 4.3.10, Analytical Services Costs.  Other labor
requirements for periodic equipment maintenance (iron
replacement) and demobilization are presented in Section
4.3.11, Equipment Maintenance Costs and Section 4.3.12,
Site Demobilization Costs.

4.3.6  Supply Costs

Necessary  supplies as part of the overall groundwater
remediation project include Level D disposable personal
protective  equipment  (PPE) and sampling and field
analytical supplies.

Disposable PPE typically consists of latex inner gloves,
nitrile outer gloves, and safety glasses. This PPE is used
during sampling activities. Disposable PPE is assumed to
cost about  $300 per year for the sampler.

Water purged from the upgradient monitoring wells during
sampling activities should be contained. Based on the well
dimensions, purging the upgradient wells will generate
about 15 gallons of water per sampling event. This cost
estimate assumes that the water could be pumped through
a carbon filter at the completion of each sampling event
and discharged to the ground  surface upgradient from the
system. This estimate assumes that carbon canisters will
require replacement annually, at a cost of $700 each,
 including  disposal/regeneration  of the spent  carbon
 (Means 1996).  If this is not feasible, additional off-site
 disposal costs  may be  incurred.  Because detectable
 concentrations of contaminants are not anticipated to be
 present in water  downgradient  from  the  system,  this
 estimate assumes that water purged from the downgradient
 wells can be discharged to the ground surface.

 Sampling  supplies consist of sample  bottles,  shipping
 containers, pump hoses  or tubing, buckets or drums to
 temporarily contain purge  water, field meter calibration
 solutions,   and other  typical  groundwater : sampling
 supplies.  The numbers and types of necessary sampling
 supplies are based on the analyses to be performed. For
 this analysis, annual sampling supply costs are assumed to
 be $1,000 (Means 1996).      --.  .••....-

 Total annual supply costs are estimated to be $2,000;
                                                     67

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 4.3.7 Utility Costs

 The   in-situ  metal-enhanced  dechlorination  system
 typically requires no utilities.
 4.3.8 Effluent Treatment and Disposal
        Costs

 This  estimate assumes that the technology will reduce
 groundwater contaminants to acceptable levels by in-situ
 treatment. For this reason, no additional effluent treatment
 and disposal costs will be incurred.

 4.3.9 Residual Waste Shipping and
        Handling Costs

 Based on existing data, it appears that the dechlorination
 process generates no residual  wastes.  This estimate
 assumes that periodic maintenance to  restore  the iron's
 hydraulic  conductivity  (see  Section  4.3.11) will  be
 accomplished  using in-situ soil  mixing  or  a similar
 process, and will not result in the  generation of soil and
 iron that requires management as a potentially hazardous
 waste.

 4.3.10 Analytical Services Costs

 Analytical  services costs  include  costs for laboratory
 analyses, data reduction, and QA/QC. Required sampling
 frequencies, number of samples, and associated QA/QC
 requirements are highly site-specific and are  based  on
 regulatory status, treatment goals, influent contaminant
 concentrations, areal extent of the contaminant plume
 (which determines the length of the iron  wall or number of
 gates), and other factors.

 This analysis assumes that the number  and  frequency of
 samples would be the same for either a continuous wall or
 funnel and gate system;  both  cases assume that three
 background  wells and six downgradient wells will  be
 sampled during each event. All of the samples will be
 analyzed  for  VOCs  to  directly   monitor  system
 performance.   The one  background well  and  two
 downgradient wells nearest the center of the wall will be
 monitored for additional parameters to track  inorganic
precipitation in the iron; bicarbonate alkalinity and metals
including calcium, magnesium, and iron, in addition to
VOCs. Based on typical costs for these analyses incurred
during the New York demonstration, costs for the VOC,
 metals, and bicarbonate analyses are assumed to be $1507
 sample,  $100/sample,  and $15/sample,  respectively.
 Analytical .costs also assume that one trip blank, one
 matrix spike, and one matrix spike duplicate sample will
 be submitted for  VOC analyses  during each event.
 Geochemical parameters (pH, Eh, DO, conductivity, and
 temperature) will be measured by sampling personnel in
 the field using portable meters.

 Assuming  the sampling frequency discussed in Section
 4.3.4 (monthly for the  first six months  and quarterly
 thereafter) a total of 84 sampling events will be performed
 over the 20-year project.  Analytical costs for these events
 prorate to about $9,000 annually.

 Core samples of the reactive iron should be collected
 periodically and analyzed to evaluate precipitate buildup.
 This estimate assumes that one sample will be collected bi-
 annually from the upgradient (influent) side of reactive
 iron, and analyzed using wet chemistry techniques and by
 microscopy. This estimate assumes that this sample could
 be collected during routine sampling activities, and that the
 analyses would cost about $600 per sample, prorating to
 $300 per year.

 Total annual analytical services costs are estimated to be
 $9,300.

 4.3.11  Equipment Maintenance Costs

 Long-term  data regarding the useful life of the reactive
 iron are not available. ETI estimates that the iron may last
 up to several decades, provided it does not become coated
 or blocked with precipitates. Periodic maintenance may be
 required to agitate the influent (upgradient) side of the iron
 to loosen precipitates, which tend to concentrate in the first
 few inches of reactive iron. It is also possible that the iron
may need  to be periodically replaced, if maintenance
techniques can not successfully loosen precipitate buildup.
The timeframe for maintenance or replacement will vary
depending on flow rate, groundwater chemistry, and other
factors (Focht, Vogan, and O'Hannesin 1996)

This cost analysis assumes that the reactive iron will not
require replacement, but will require maintenance every 7
years to maintain flow through the system, or twice during
the 20-year project.   According to  ETI, this may be
accomplished  using  augers  or  in-situ  soil mixing
equipment to agitate the influent face of the reactive iron
and loosen precipitates.  However, this technique has not
                                                   68

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been  attempted in a  field setting,  and  therefore its
feasibility and effectiveness are currently undemonstrated.
For this reason, actual costs to perform iron maintenance
are unknown.

Based on  mobilization and operating  costs  typically
associated with highly-specialized heavy equipment, for
each maintenance  event labor, equipment mobilization,
decontamination, and operating costs for iron maintenance
are assumed to be equal to about 30 percent of the original
iron costs, or $40,500, for the continuous wall.  Costs are
assumed to be slightly less, equal to about 20 percent of the
original iron costs, or $27,000, for the runnel and gate
system due to the shorter total length of the reactive iron
gates (Focht, Vogan, and O'Hannesin 1996; Means 1996).
Assuming  that iron maintenance will be required twice
during the remediation project, estimated annual iron
restoration costs prorate to about $4,100 for the continuous
wall and $2,700 for the funnel and gate system, but could
vary  significantly from these estimates, particularly  if
portions of the iron need to be replaced.  Also, if it  is
necessary to remove monitoring wells to provide clear
access to the upgradient side of the iron, additional well
replacement costs may be  incurred.

4.3.12 Site Demobilization Costs

Site demobilization includes removal of the reactive iron;
site cleanup and restoration; and off-site transportation and
disposal of the spent iron.  Excavation and removal of the
iron could be accomplished with a conventional backhoe.
This  estimate assumes that the iron is non-hazardous and
will bear a recycling credit of 3-5 percent of its original
value (about  $4,000 to  $7,000).   Based  on these
assumptions, no net costs for removal of the iron are
incurred.  Backfill of the trench would be completed using
a backhoe and clean fill, at a cost of about $10 per cubic
yard. The nine monitoring wells would be removed and
the boreholes grouted to the ground surface at a cost of $20
per foot, for a total cost of about $3,000.  Based on these
assumptions, net total iron removal and trench backfill
 costs are  assumed  to be about  $5,000  after the  iron
recycling credit.

 For the three-gate funnel and gate system, the iron would
 be removed and recycled, and the sheet piling would also
 be removed and hauled away as scrap, assuming it is non-
 hazardous. The monitoring wells would be removed and
 disposed of as non-hazardous demolition debris. The gate
 areas would be brought to grade with clean fill. Net total
costs for removal of the system and backfill for the funnel
and gate  system are assumed to be the same as for the
continuous wall, after recycling credits for the iron and
sheet piling ($5,000).

Final site restoration costs may include optional regrading
and seeding of the area.  These costs are highly site-
specific; in this case, costs are assumed to be $6,000.

Total  demobilization  and  site restoration  costs  are
assumed to be $11,000 for the continuous wall or for the
funnel and gate system. If the iron or sheet piling require
management as  a  hazardous waste,  or do not bear the
assumed recycling value, demobilization costs could be
significantly higher.

4.4   Economic Analysis Summary

This   analysis presents   cost  estimates for  treating
groundwater contaminated with TCE, cDCE  and VC.
Two options are discussed; a continuous reactive wall, and
a three-gate  funnel  and  gate   system.    Operating
assumptions  include  treating  a  minimum  saturated
thickness of 10 feet of groundwater flowing at a rate of
6.75 foot per day through a continuous wall, or 3.75 feet
per day for a funnel and gate system. Table 4-1 shows the
estimated costs  associated with the 12 cost categories
presented in this analysis for the continuous wall. Table 4-
2 shows the estimated costs for the funnel and gate system.
Costs were not adjusted for inflation.

For the continuous wall, total fixed costs are estimated to
be about $466,600. Site preparation costs comprise about
57.6 percent of the total fixed  costs; capital equipment
accounts for about 30.6 percent of the fixed costs. Figure
4-1 shows the distribution of fixed costs for the continuous
wall. Total annual variable costs are estimated to be about
$20,900.  Analytical services (excluding sampling labor)
comprise about  44.5 percent of the variable costs; labor
(sampling and ordinary O&M) costs account for about
26.3 percent of these costs. The variable costs also include
estimated costs for iron maintenance activities assumed to
be required twice  during the 20-year project; distributed
over the 20-year timeframe these costs account for about
 19.6 percent of the annual variable costs. Figure 4-2 shows
the distribution of annual variable costs for the continuous
wall.

After operating for 20 years, the total fixed and variable
 costs  for the  continuous  wall  remediation  scenario
                                                     69

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presented in this analysis are estimated to $884,600.  A
minimum of about 49.1 million gallons of groundwater
would be treated over this time period, assuming flow
velocities remain constant at 0.75 foot per day, and the
porosity and hydraulic conductivity of the  entire wall
remain unchanged. Based on these criteria, the total cost
per 1,000 gallons treated is about $ 18.02, or about 1.8 cents
per gallon.

Figures 4-3 and 4-4 exhibit breakdowns of the estimated
fixed and variable costs associated with the funnel and gate
system, respectively. As shown on Figure 4-3, the  major
differences between the costs for the continuous wall and
the funnel and gate  system are  in  the site preparation
portion of the  fixed costs.  Although fixed costs for the
funnel and gate system are considerably higher, higher
maintenance costs are assumed  to  be required for the
continuous wall due to the greater length of iron wall that
will require maintenance.  For this reason, the estimated
cost per gallon of groundwater treated for the funnel and
gate system (about 2 cents) is only slightly higher than for
the continuous wall. The volume of groundwater treated is
assumed to be the same in both cases. However, the actual
amount of groundwater that would pass through the funnel
and gate system would depend on the degree to which the
system can  accelerate  the natural  groundwater   flow
velocity, and therefore may  differ from the amount that
would pass through a continuous wall. For this reason, and
other reasons previously discussed, actual costs may vary
significantly from estimates presented in this report.
                                                   70

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                          $11,000 (2.4%) Demobilization
    $143,000 (30.6%) Capital Equipment
                $4,000 (0.9%) Permitting

      $40,000 (8.6%) Mobilization and Startup
                                                                          $268,600 (57.6%) Site Preparation
 Total Fixed Costs are estimated to be $466,600.
Figure 4-1, Distribution of fixed costs for continuous wall.
    $9,300 (44.5%) Analytical Services
                                 $2,000 (9.6%) Supplies
                                                                   $4,100 (19.6%) Equipment Maintenance
                                                                         $5,500 (26.3%) Labor
Notes:  1) Total Annual Variable Costs are estimated to be $20,900.
       2) Routine sampling and O&M labor; does not include iron restoration.
 Figure 4-2. Distribution of annual variable costs for continuous wall.
                                                    71

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                                 $11,000 (1.9%) Demobilization
      $143,000 (25.0%) Capital Equipment
          $4,000 (0.7%) Permitting

  ,500 (5.7%) Mobilization and Startup
                                                                                         $382,100 (66.7%) Site Preparation
    Total Fixed Costs are estimated to be $570,600.
Figure 4-3. Distribution of fixed costs for funnel and gate system.
  $9,300 (47.7%) Analytical Services
                                                                         $2,700 (13.8%) Equipment Maintenance
                                                                                         $5,500 (28.2%) Labor
                                                                  $2,000 (10.3%) Supplies
          Notes:  1) Total Annual Variable Costs are estimated to be $19,500.
                 2) Routine sampling and O&M labor; does not include kon restoration.
Ffgure 4-4.  Distribution of annual variable costs for funnel and gate system.
                                                          72

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                                              Section 5
                        Technology Status and Implementation
ETI has completed several bench-scale studies, five pilot-
scale tests using aboveground reactors and in-situ reactive
walls, and six full-scale installations of in-situ systems.
Several other field tests of in-situ installations are planned
for the near future in Massachusetts  and Hawaii.  ETI is
completing   cooperative  research  and  development/
licensing arrangements with several U.S. and multinational
industrial firms.

The in-situ implementation  of the technology  involves
installing a permeable treatment wall of coarse-grained
iron medium across the groundwater plume.  The iron
degrades chlorinated VOCs  as they  migrate through the
wall   under   naturally occurring  groundwater  flow
conditions. When the in-situ metal-enhanced dechlorination
technology  is  applied to   treat   a  large  plume  of
contaminated groundwater,  impermeable sheet  piles or
slurry walls may be used to funnel  contaminated
groundwater through  smaller  permeable  treatment
 sections, known as gates. Selection of the appropriate type
 of system depends on site-specific factors.

 The metal-enhanced dechlorination process also may be
 employed aboveground. Aboveground treatment units are
 designed to  treat extracted  groundwater.  Aboveground
 treatment  units can  be  available as  trailer-mounted
 transportable  units or permanent installations.   The
 configuration of the aboveground  units may include a
 single unit  or  several units  connected in series  or  in
 parallel.

 The  metal-enhanced  dechlorination   technology  is
 implemented through a four-phase approach.  A site data
 assessment  is conducted during phase  1; a feasibility
 evaluation involving bench-scale testing (and pilot-scale
 testing if necessary) is conducted during phase 2; system
 design, costing, and construction occurs during phase 3;
 and phase 4 involves long-term performance monitoring.
 Phases  1 and 2 may take about 2 to 4 months, and phase 3
may take about 6 months.  The duration of phase 4 will
depend  on  site-specific  conditions  and  regulatory
requirements.  The phases are described  in subsequent
sections.

Phase  1 - Site Data Assessment

The purpose of a site data assessment is to review existing
data to evaluate site  conditions that may affect  the
performance of the technology.  On the basis of this
review, the site may be placed into one of two categories.
The first category includes sites with a physical setting and
groundwater chemistry similar to other sites at which the
metal-enhanced dechlorination  technology  has been
shown to be effective. Therefore, implementation of phase
2 (a feasibility evaluation) is not necessary before phase 3
activities begin.

The second category includes sites with unique physical
 and geochemical properties that may affect the application
 of the  metal-enhanced dechlorination technology. The
 probability for the successful application of the technology
 at these sites is unknown, due to the presence of untested
 chemicals, unusual  inorganic  chemistry,  or unusual
 geologic settings. For these sites, implementation of phase
 2 activities is needed before phase 3 activities can begin.
 Data that are necessary to assess a site include:

        Groundwater inorganic and organic chemistry:
        The inorganic chemistry of groundwater is impor-
        tant because it indicates whether metals can pre-
        cipitate during treatment. The effect of metal pre-
         cipitation on the performance of the technology is
         discussed in Section 3.1.1.  The nature of organic
         contaminants present in groundwater determines
         the applicability of the technology to a particular
         site, as discussed in Section 3.1.1.
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         VOC characteristics: The technology is appro-
         priate for treating chlorinated methanes, some
         ethanes, and ethenes.  Each compound and its po-
         tential by-products have a half-life. The half-life
         of each compound and its  degradation by-prod-
         ucts are critical parameters with regard to residence
         time when designing a treatment system.

         Site geology and soils:  The type of materials,
         depth to water, saturated thickness, and presence
         of an underlying aquitard are important consider-
         ations for the design and implementation of in-
         situ installations of the metal-enhanced dechlori-
         nation technology.

         Hydrogeological data: Horizontal gradient, hy-
         draulic conductivity and groundwater flow veloc-
         ity will affect the performance of the metal-en-
         hanced dechlorination technology because they
         influence the residence time of groundwater in the
         reactive wall, which affects the required wall thick-
         ness.
 Phase 2 - Feasibility Evaluation

 If the site is placed into the second category as defined in
 phase 1,  a  feasibility evaluation is typically performed.
 The purpose of phase 2 is to evaluate the efficiency of the
 metal-enhanced dechlorination technology under simulated
 groundwater flow conditions, by performing laboratory
 bench-scale  (column)  tests   using  representative
 groundwater samples collected from the site. Groundwater
 flow and geochemical models may be used to assist in the
 feasibility evaluation.   Feasibility  testing  should  (1)
 confirm that  the  VOCs present are degraded by  the
 process, (2) evaluate the rates of VOC degradation, and (3)
 evaluate associated inorganic geochemical reactions.

 Following successful laboratory bench-scale tests, a pilot-
 scale field test may be conducted to collect additional data
 to support full-scale application of the process; however,
 according to ETI, pilot-scale testing is no longer typically
 required.  Pilot-scale testing may not be required, or may
 be very limited for sites having contaminant, geochemical,
 and hydrogeologic characteristics similar to other sites for
 which ETI has extensive past performance data. However,
 it is important to  note  that because the technology is
 relatively  new,  state regulatory authorities  may still
require a pilot-scale study if the technology has not been
shown to be effective in that particular state. If pilot-scale
  testing is required, the'results of the bench-scale studies are
  used to design the pilot-scale system.  The pilot-scale
  system may be in-situ or aboveground, depending on the
  potential full-scale application and site conditions:  This
  field test provides data which are readily extrapolated to
  estimate  full-scale costs, long-term performance and
  operation, and maintenance requirements.

  A feasibility evaluation report is prepared to document
  phase 2 testing results.  The report interprets the laboratory
  data with respect to the site's hydrogeologic characteristics
  and provides  information required for the preliminary
  design and cost estimating activities performed in phase 3.

  Phase  3   -  System   Design,   Costing,  and
  Implementation

  Phase 3 is the design, costing, and construction of a full-
  scale system.  The results from phase 2 provide the basis
  for full-scale design.   The half-lives of the chlorinated
  VOCs present in the groundwater and the  half-lives of
  potential dechlorination by-products, determined through
  bench-scale  testing, and data collected during the pilot-
  scale testing (if required), are used to confirm the correct
  volume  of iron  required  to  treat  the  types   and
  concentrations of contaminants present.  The full-scale
 system dimensions  are determined based  on the total
 residence  time necessary  for dechlorination; the flow
 velocity, and the contaminant plume dimensions.  These
 criteria determine the thickness of the reactive iron wall in
 an in-situ system.   For in-situ systems, hydrogeologic
 factors such as saturated thickness and plume dimensions
 will also influence the full-scale system design.

 Once the full-scale system design is finalized, the system is
 constructed.  According to ETI, steady state operating
 conditions are typically achieved by the time about 20 to
 30 pore volumes of groundwater has passed through the
 system (ETI  1994).

 Phase 4 -  Long-Term  Performance Monitoring
 and Maintenance

 Routine  performance   monitoring  and  reporting  are
performed  according  to   regulatory  requirements.
Performance  monitoring includes sampling and analysis
of treated groundwater to determine the concentrations of
VOCs of concern.     Decreases  in dissolved  metal
concentrations indicate formation of insoluble precipitates
that may clog the reactive iron medium.
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As discussed in Section 3, periodic maintenance may be
required to  restore  the hydraulic  conductivity and
reactivity of the iron. ETI estimates that for full-scale in-
situ systems, these activities may be required every 5 to 10
years.
                                                       75

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                                             Section 6
                                            References
 Appleton, Elaine.  1996.  "A Nickel-Iron Wall Against
   Contaminated Groundwater." Environmental Science
   and Technology News, Volume 30, Number 12.

 Chen, Chien T. 1995. Excerpts from Presentation Titled
   "Iron Reactive Wall."  Innovative Site Remediation
   Workshop, Sturbridge, Massachusetts. September 13-
   14.

 EnviroMetal Technologies, Inc. (ETI).  1994.  Revised
   Draft: Rationale for Suggested Design and Monitoring
   Program, Pilot Scale Field Trial of the EnviroMetal Pro-
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 ETI.  1996a. Draft Evaluation Report; Pilot-Scale Funnel
   and Gate, New York. Prepared for Steams andWheler
   L.L.C.(S&W). March.

 ETI.  1996b. Draft Correspondence Regarding Ground-
   water Flow Velocity Measurements. From John Vogan,
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 Gillham, Robert W, and Stephanie F. O'Hannesin. 1994.
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   Anaheim, California. April 2-7. Pages 691-694.

 Gillham, Robert W. 1996. "In-Situ Treatment of Ground-
   water: Metal-Enhanced Degradation of Chlorinated
   Organic Contaminants." Recent Advances in Ground-
   water Pollution Control and Remediation. M.M. Aral
   (ed.), Kluwer Academic Publishers. Pages 249-274.

 O'Hannesin, Stephanie F., and Robert W. Gillham.  1992.
   "A Permeable Reaction Wall for In-Situ Degradation of
   Halogenated Organic Compounds." Paper Presented at
   the 1992, 45th Canadian Geotechnical Society Confer-
   ence. Toronto, Ontario, Canada.  October.

O'Hannesin, Stephanie F., 1993.  "AField Demonstration
   of a Permeable Reaction Wall for In-Situ Abiotic Deg-
   radation of Halogenated Organic Compounds." (M.Sc.
   Thesis, University of Waterloo.)

Means, R.S. Company, Inc. (Means). 1996. Environmen-
   tal Restoration Assemblies Cost Book.  R.S. Means
                                                  76

-------
  Company, Inc., Kingston, Massachusetts.

PRC Environmental Management, Inc. (PRC).  1995.
  EnviroMetal Technologies, Inc. "Metal Enhanced Abi-
  otic Degradation Technology SITE Program Demon-
  stration Final Quality Assurance Project Plan."  Sub-
  mitted to EPA ORD, Cincinnati, Ohio. May.

PRC. 1996. Record of Telephone Conversation Regard-
  ing Inorganic Data from New York
Demonstration.  Between Guy D. Montfort, Project Man-
  ager, and John Vogan, ETI. December.

PRC. 1997. Record of Telephone Conversation Regard-
   ing Full-Scale Funnel and Gate Design.  Between Guy
   D. Montfort, Project Manager, and Rob Focht, ETI.
   January.

Puls, R., Powell, R., and Paul,  C.  1995.  "In-Situ
   Remediation of Ground Water Contaminated with Chro*-
   mate and Chlorinated Solvents Using Zero-Valent Iron:
   a Field Study. Presented Before the Division of Envi-
   ronmental Chemistry. American Chemical Society.
   Anaheim, California.  April 2-7. Pages 788-791.

 •Reardon, Eric.  1995.  "Anaerobic Corrosion of Granular
   Iron: Measurement and Interpretation of Hydrogen Evo-
   lution Rates."  Environmental Science & Technology,
   Volume 29, No. 12. Pages 2936-2945.

 Snoeyink, Vernon L.  and David Jenkins.  1980.  Water
   Chemistry. John Wiley & Sons. New York.

 Stearns  and Wheler, Inc. (S&W).  1993. Final Remedial
   Investigation Report (for the New York Demonstration
   Site). January.

 S&W.  1994. Draft Work Plan for the Field Trial of the
   EnviroMetal Process. October.

 U.S. Department of Energy (DOE).  1988. Radioactive
    Waste Management Order. DOE Order 5820.2A. Sep-
    tember.

 EPA. 1987.  Joint EPA-Nuclear Regulatory Agency Guid-
    ance on Mixed Low-Level Radioactive and Hazardous
    Waste. Office of Solid Waste and Emergency Response
    (OSWER) Directives 9480.00-14 (June 29), 9432.00-2
    (January 8), and 9487.00-8. August.
EPA.  1988a. Protocol for a Chemical Treatment Demon-
  stration Plan. Hazardous Waste Engineering Research
  Laboratory.  Cincinnati, Ohio. April.

EPA.  1988b. CERCLA Compliance with Other Environ-
  mental Laws: Interim Final. OSWER. EPA/540/G-89/
  006. August.

EPA.  1988c. Guidance for Conducting Remedial Investi-
  gations and Feasibility Studies Under
   CERCLA. OSWER. EPA/540/G-89-004.  October.

EPA.  1989.   CERCLA Compliance with Other Laws
   Manual: Part II. Clean Air Act and Other Environmen-
   tal Statutes  and State Requirements.  OSWER. EPA/
   540/G-89-006. August.

EPA.  1997.   Metal-Enhanced Dechlorination of VOCs
   Using an Aboveground Reactor. SITE Program Inno-
   vative Technology Evaluation Report EPA /540/R-96/
   503. Office of Research and Development - National
   Risk Management Research Laboratory. July.

 Yamane, C.L., S. Warner, J. Gallinatti, F. Szerdy and T.
   Delfino.  1995.  Installation of a Subsurface Ground-
   water Treatment Wall Composed of Granular Zero-Va-
   lent Iron. Preprint Extended Abstract Presented before
   the Division of Environmental Chemistry. ACS.  Ana-
   heim, California. April 2-7. Pages 792-795.
                                                    77

-------
                                             Appendix A
                           Vendor's Claims for the Technology
 The  metal-enhanced  dechlorination technology uses a
 metal (usually iron) to enhance the abiotic degradation of
 dissolved halogenated organic compounds.  Laboratory-
 scale and field-scale pilot studies conducted over the past
 5 years at the Waterloo Centre for Groundwater Research,
 University of Waterloo, and at several commercial sites in
 the  U.S., have shown  that  the process can  be used
 effectively  to  degrade  halogenated  methanes,   some
 ethanes, and ethenes over a wide range of concentrations.
 These studies have shown that:

   ป     The degradation kinetics appear to be pseudo first-
        order (i.e., die rate of reaction is directly propor-
        tional to the concentration of the reactants)

   •     With few exceptions, no persistent products of
        degradation have been detected and degradation
        appears to be complete given sufficient tune

   •    The degradation rates of chlorinated compounds
       are several orders of magnitude higher than those
       observed under natural conditions

  •    The reaction rate is dependent on the surface area
       of iron available

A.1    Advantages and Innovative
       Features

  •    Reactants are relatively inexpensive

  *    The treatment is passive and requires no external
       energy source

  •    Contaminants are degraded to harmless products,
       rather than being transferred to another medium
       requiring subsequent treatment, regeneration, or
       disposal
        The reactive iron is highly persistent with, depend-
        ing upon the application, the potential to last for
        several years to decades without having to be re-
        placed

        The process is one of the few that appears to have
        potential for passive in-situ treatment

   •    The process degrades a wide range of chlorinated
        volatile  organic  compounds,   including
        trichloroethene,  tetrachloroethene, cis-1,2-
        dichloroethene,  and vinyl chloride.  Preliminary
        tests suggest that it may be applicable for a wider
        range of compounds in addition to chlorinated "ali-
        phatic" hydrocarbons.

 A.2   Technology Status

 The first full-scale in-situ  installation of the,technology
 occurred at an industrial facility in California in December
 1994.  Eleven installations of either pilot or full-scale
 systems have  been completed  to date.   These in-situ
 installations and others planned in 1997 will assist in the
 assessment  of the long-term field  performance of the
 technology.

 The results collected to date show that the ETI technology
 could be a highly effective aboveground or in-situ method
 of remediating  waters containing chlorinated aliphatic
 compounds.   An in-situ permeable treatment wall  of
 coarse-grained reactive media installed  across the plume
 will degrade compounds as they migrate through the zone
 under naturally occurring groundwater flow conditions.
 By  utilizing  impermeable sheet piles or slurry walls, a
 large plume of contaminated groundwater can be funneled
through smaller permeable treatment sections.
                                                   78

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                                            Appendix B
                                           Case Studies
This appendix summarizes several case studies on the use
of metal^enhanced dechlorination technology. These case
studies involve bench-scale units, pilot-scale units, and
full-scale units treating contaminated groundwater. The
information available for these case studies ranged from
detailed analytical data to limited information on system
performance and cost. Results from five case studies are
summarized in this appendix.

B.1    Semiconductor Facility, South San
        Francisco Bay, California

B.1.1 Project Description

Several   studies  were  performed   by  EnviroMetal
Technologies,  Inc. (ETI), using groundwater  from a
former semiconductor manufacturing site in South San
Francisco Bay, California to examine the feasibility of
constructing and operating an in-situ permeable wall
 containing a reactive iron medium to replace an existing
 pump-and-treat system.  Groundwater at this site was
 contaminated  with  trichloroethene (TCE),  cis-1,2-
 dichloroethene (cDCE),  vinyl chloride (VC), and Freon
 113. Results of laboratory column studies performed by
 ETI indicated that the concentration of dissolved volatile
 organic  compounds  (VOCs) in the groundwater was
 significantly reduced.  Following the laboratory studies,
 pilot- and full-scale units were installed.

 B.1.2 Results

 Pilot-Scale System

 An aboveground demonstration reactor, containing 50
 percent iron by weight and 50 percent sand by weight was
 installed and operated over a 9-month period. Groundwater
 was pumped through the demonstration reactor at a flow
 velocity of 4 feet per day.
The groundwater at the semiconductor facility site was
highly mineralized.  Although precipitate formation was
evident at the influent end of the test reactor, the rate of
degradation remained relatively constant  over  the  9-
month test period. The following were the pilot-scale test
results:

       TCE, 210 ppb, 1.7-hour half-life

       cDCE, 1,415 ppb, 0.9-hour half-life

       VC, 540 ppb, 4.0-hour half-life

 Several other aspects of the metal-enhanced dechlorination
 process  were  evaluated during  this  pilot-scale  test,
 including the following.

   •    Metals precipitation - Inorganic gebchemical data
        collected in the field was used to predict the po-
        tential for precipitate formation in the reactive iron
        material. Operation and maintenance requirements
        for the full-scale design were based on the evalu-
        ation of the metals precipitation data.

        Hydrogen gas production - Hydrogen gas may
        be produced as a consequence of the dissociation
        of water in the presence of granular iron. Rates of
        hydrogen gas generation measured in the labora-
        tory (Reardon 1995) were used to evaluate the need
         for any hydrogen gas collection system in the full-
         scale application. Based on the evaluation, no need
         for a hydrogen gas collection system was indicated.

         Microbial Effects - Groundwater from within the
         reactor was sampled for microbial analysis.  The
         results indicated that the microbial population in
         the reactor was similar to the population observed
         in untreated groundwater.  There was no visual
         evidence of biomass generation during the test.
                                                     79

-------
  Full-Scale System

  Based on the pilot-test results, a full-scale in-situ treatment
  wall was installed in December 1994. The reactive wall
  was 4 feet thick, 40 feet long, and situated vertically
  between depths of about 7 feet and 20 feet below ground
  surface.  The 4-foot-thick zone of 100 percent granular
  iron was installed to achieve a hydraulic residence time of
  about 4 days to treat VOCs to cleanup standards, based on
  the estimated groundwater velocity of 1 foot per day. VC
  required the longest residence time to degrade to cleanup
  standards.  A layer of pea gravel about 1  foot thick was
  installed on both the upstream and downstream sides of the
  reactive wall. The reactive wall was flanked by slurry
  walls to direct groundwater flow towards the reactive iron
  medium. The construction cost for the reactive wall was
  about $225,000. Together with slurry walls, capital costs
  were about $720,000.

  At the time tin's report was prepared, minimal data for the
  full-scale system were available. Monitoring wells were
  installed near the upstream and downstream faces. Initial
  results indicate that chlorinated VOCs are  being reduced
  to below regulatory levels. For further details see Yamane
  etal 1995 and Szerdy and others 1995.

 Sources:  Yamane  and others  1995; Szerdy and others
  1995; ETI1996; Focht, Vogan, and O'Hannesin 1996.

 B.2   Canadian Forces Base, Borden,
        Ontario, Canada

 B.2.1  Project Description

 In May 1991, a small-scale in-situ field test was initiated at
 the Borden site to  treat groundwater contaminated with
 TCE and PCE. The source of the contaminant plume at the
 site was located about 4 meters (m) below ground surface
 and 1 m below the water table. The plume was about 6.6
 feet  wide  and  3.3  feet  thick,  with   a maximum
 concentration along the axis of about 250,000 and 43,000
 ug/L for  TCE and  PCE, respectively.   An  in-situ
 permeable wall was constructed about 18 feet downgradient
 from  the source.   The aquifer material consisted of a
 medium to  fine sand, and the average  groundwater
 velocity was about 0.3 feet per day.

The reactive wall was constructed by driving sheet piling
to form a temporary cell 5.2 feet thick and  18 feet long.
The native sand was replaced by the reactive iron medium,
  consisting of 22 percent iron grindings by weight and 78
  percent coarse sand by weight. After the reactive iron
  medium was  installed, the sheet piling was removed,
  allowing the contaminant plume to pass through the wall.

  Rows of multilevel  samplers  were  located 1.6 feet
  upgradient from the wall, at distances of 1.6 feet and 3.3
  feet into the wall, and 1.6 feet downgradient from the wall,
  providing a total of 348 sampling points.

  B.2.2 Results

  Samples were collected and analyzed  over a five-year
  monitoring period.  There was no apparent change  in
  performance and no maintenance required over the five-
  year duration of the test. The results indicated that about
  90 percent of the TCE and  86 percent of the PCE was
  removed as the contaminant plume passed through the
  wall.  Amounts of dechlorination by-products (tDCE and
  cDCE) equivalent to about 2 percent of the original mass
  of TCE and PCE present in the influent were detected at
  sampling  points  within the  wall.   However,  these
  byproducts also were dechlorinated with further distance
 through the  wall.  An observed  increase in chloride
 concentrations  in  effluent  samples indicated that the
 decline  in  TCE  and  PCE  concentrations  was   a
 consequence of dechlorination processes. Although the
 effluent did not achieve drinking water standards, based on
 current knowledge it  appears that  use of a greater
 proportion  of iron relative to contaminant loading, or use
 of a more  reactive form of iron, could have improved
 performance. No VC was detected as a result of PCE,
 TCE, or cDCE degradation, and no bacterial growth was
 observed.   Examination of the iron medium by X-ray
 diffraction  and scanning electron microscopy did not
 indicate the  presence  of precipitate on the reactive
 material.

 Source: Gillham 1996.

 B.3    Industrial Facility, Kansas

 B.3.1 Project Description

A groundwater  investigation during the early  1990s
identified a TCE plume, with concentrations ranging from
 100 to 400 ppb (ug/L), egressing from an industrial facility
in Kansas.   The TCE occurs in a basal alluvial sand and
gravel zone overlying the local bedrock, at a depth of
about 30 feet below ground  surface. In mid-1995,  a
                                                  80

-------
treatability study was conducted on groundwater from the
facility to determine the effectiveness of granular iron in
degrading  chlorinated  organic  compounds  in  the
groundwater.

The treatability study consisted of pumping groundwater
from the site through a laboratory column containing the
iron material. The column test provided site-specific
information on (1) the dechlorination rate of TCE; (2) the
potential for the formation and degradation of chlorinated
by-products; and  (3)  potential  inorganic  chemical
changes. The results of this study were used to determine
the required residence time necessary for the dechlorination
of TCE and its degradation products.

A groundwater model of the site  was then generated,
incorporating various funnel and  gate configurations.
This model helped to determine the size of the in-situ
system  necessary  to  capture and treat the plume of
contaminated groundwater, and to estimate the expected
groundwater velocity through the  gate.  The velocity
estimate, together  with the required residence time
determined from the treatability study, were used to
determine the necessary thickness of the iron section in the
gate.

During December 1995  through January 1996 a 1,000-
foot-long funnel and gate system  was installed at the
facility property boundary.  A low natural groundwater
velocity permitted the use of a high funnel-to-gate ratio;
the velocity increase due to the tunneling action permitted
a reasonably small treatment zone to be built. The system
was constructed with about 490 feet of impermeable
funnel  on either side of  a  20-foot long reactive gate.
Construction of the funnel sections was accomplished by
first constructing a single, soil-bentonite slurry wall. After
the wall had set, the 20-foot gate section was excavated in
the middle of the wall. The iron zone was tปien installed in
the gate section, measuring about 13 feet deep and about 3-
 feet wide (that is, the flow-through thickness was 3 feet).
 Weather delays and other non-technical delays extended
 the construction  period; however,  the construction
 contractor estimated that under optimal conditions the
 slurry wall could have been built in two weeks, and the
 reactive gate section in one week.

 B.3.2 Results

 Costs for the installation (slurry walls and gate) were about
 $400,000, including 70-tons of granular, reactive iron.
Results to  date show nondetectable concentrations of
VOCs in the wells screened in the gate. For further details
see Focht, Vogan, and O'Hannesin 1996.

Sources: ETI1996; Focht, Vogan, and O'Hannesin 1996.

B.4    U.S. Coast Guard Facility, North
        Carolina

In June 1996, an in-situ reactive wall was installed near a
former machine shop at a U.S. Coast Guard facility in
Elizabeth City,  North  Carolina, using a continuous
trenching technique, to treat a groundwater contaminant
plume with TCE concentrations of about 10 mg^L and
hexavalent chromium also at about 10 mg/L. The reactive
wall measures about 150 feet in length, 2 feet in width, and
extends to about 26 feet bgs.

For excavation, continuous trenching was performed with
a  cutting chain excavating system, similar to a Ditch
Witch™.  As the chain  excavator  moved  across the
designated trench  boundary, soils were brought to the
surface and deposited onto the ground surface. The soils
were  eventually analyzed for hazardous constituents and
removed from the site. A steel trench box, extending to the
width and depth of the trench, was  pulled immediately
behind the chain excavator and served to keep the trench
open  and allow the emplacement of granular iron into the
trench. Through a hopper above the trench box, granular
iron  was fed  into and  through  the trench box to the
excavated  area.   This process, which  involved the
placement of about 450 tons of iron, was continued for the
entire length of the trench and was completed in a single
day. Total cost of the installation was about $500,000 with
the iron costing just under $400 per ton.

Source: Blowes and others 1997; ETI 1996

B.5    Lakewood Colorado Facility

The largest in-situ funnel and multiple gate system to date
was  installed  from July through November 1996 at  a
government facility in Lakewood, Colorado. The facility
is underlain by unconsolidated sediment and bedrock
aquifers, with the bedrock surface at about 25 feet bgs.
Groundwater contamination at the facility, mainly VOCs,
 is present in both aquifers at varying concentrations (TCE
 and DCE: 700 ug/L maximum; vinyl chloride: 15 ug/L
 maximum), and over a widespread area.
                                                     81

-------
 A sheet piling wall, which serves as the funnel for this
 system, was installed over a length of 1,040 feet and to a
 depth of 25 feet bgs.  Four 40-foot long reactive gate
 sections  with varying thicknesses  were  installed  at
 designated locations along the wall. Varying gate section
 thicknesses were used to compensate for variations  in
 groundwater flow velocities and VOC concentrations in
 different  parts of the site.  In accomplishing the funnel
 installations, sheet  piling boxes  were erected at  each
 location and native material was  excavated from inside
 each box. A thin layer of pea gravel was then placed at the
 bottom of each excavation followed by granular iron up to
 about 9 to 13 feet bgs.

 Groundwater flow velocities are expected to range from
 less than 1 foot per day (ft/day) to about 10 ft per day; data
 collection is currently underway to determine these. Initial
 monitoring  data indicate that  effluent  contaminant
 concentrations are meeting the design criteria.

 Source: ETI1996.

 B.6   References

 Blowcs, D.W., R.W. Puls, T.A. Bennett, R.W. Gillham, C. J.
   Hanton-Fong, and CJ. Ptacek.  1997. "In-Situ Porous
   Reactive Wall for Treatment of Cr(VI) and Trichloroet-
   hylene in Groundwater." 1997 International Contain-
   ment Technology Conference and Exhibition, St. Pe-
   tersburg, Florida. February 9-12.

 EnviroMetal Technologies, Inc. (ETI). 1996-Case Studies
   for Various Applications of the Metal-Enhanced Dechlo-
   rination Process. November 5.

 Focht, R.  J. Vogan, and S. O'Hannesin.  1996.  "Field
   Application of Reactive Iron Walls for In-Situ Degra-
   dation of Volatile Organic Compounds in Groundwa-
   ter".  Published in "Remediation;" Volume 6, No. 3.
   Pages 81-94.

Gillham, R. W. 1996.  "In-Situ Treatment of Groundwa-
   ter: Metal-Enhanced Degradation of Chlorinated Or-
   ganic Contaminants." Recent Advances in Groundwa-
   ter Pollution Control and  Remediation. M. M. Aral
   (ed.), Kluwer Academic Publishers. Pages 249-274.

O'Hannesin, Stephanie F., 1993. "A Field Demonstration
   of a Permeable Reaction Wall for In-Situ     Abiotic
   Degradation of Halogenated Organic Compounds."
   (M.Sc.  Thesis, University of Waterloo.)

Szerdy, F.S., J.D. Gallinatti, S. D. Warner, C. L. Yamane,
   D.A. Hankins, and J. L. Vogan. 1995." In-Situ
   Groundwater Treatment by Granular Zero-Valent Iron -
   Design, Construction and Operation of an In-Situ Treat-
   ment Wall." Published by Geomatrix Consultants, Inc.
   San Francisco, California.

Yamane, C.L., et. all995.  "Installation of a Subsurface
   Groundwater Treatment Wall Composed of  Granu-
   lar Zero-Valent Iron." Preprint Extended Abstract Pre-
   sented before the Division of Environmental Chemis-
   try. ACS. Anaheim, California. April 2-7. Pages 792 -
   795.
                                                   82

-------
     Appendix C
Analytical Data Tables
          83

-------
Tabl'8 C-1.  Summary of Analytical Data-June
SAMPLE
Dili
SUBSTANCE DETECTED
VOCs (mlcrognmtMif);
Acetone
Chloroform
1.1-DfcMoroethane
cls-1.2-dtchloroethene
trans-1,2-d!cWoroetherte
Telrachloroethene
1,1.1-Trichloroethiuio
Trichloroethene
Vinyl chloride
Tentatively Identified Compounds (total)
Mttals (milligrams/liter):
Aluminum
Barium
Calcium
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Potassium
Sodium
Zinc
Wet Chemistry (milligrams/liter}:
Bicarbonate Alkalinity
Chloride
Nitrate/Nitrite Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
SuHate
Total Phospholipld Fatty Acid*:
(Average; pfcomoles/liter)*
MW-U1
06/07/95


5.00
1.00
1.5
160
1.00
1.00
4.6
130
7.1
3J

Z96
0.0227
71.3
0.010
0.020
4.49
0.0050
11.2
0.415
2.05
29.2
R.021B

167
48
0.529
0.47
0.0591
19

22,188
HW-U2


5.00
1.00
1.9
220
1.00
1.00
6.5
170
8.3
3J

1.5
0.020
66.7
0.010
0.020
2.42
0.0050
10.0
0.241
1.59
27.4
0.0146

162
49
0.57
0.525
0.0451
20.8

14,865
MW-U3
06/07/35


5.00
1.00
1.1
120
1.00
1.00
3.2
74
4.9
2J

3.32
0.020
93
0.010
0.020
6.34
0.050
14.9
0.393
2.68
38.7
0.0277

139
48.4
0.332
0.307
0.0251
19.1

45,310
HW-FE1
06/07/3S


5.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
3J

0.10
0.535
12.8
0.0155
0.0422
16.6
0.0050
5.7
0.245
1.54
35.4
0.010

17.2
53.8
0.0591
0.0591
0.010
18.8

34,166
MW-FE2
OS/08/S5


12
1.00
1.00
1.6
1.00
1.00
1.00
1.00
1.00
3J

2.37
0.521
18.6
0.0172
0.0361
27.8
0.0050
4.02
0.56
2.26
36.1
0.0205

18.5
53.7
0.0609
0.0501
0.0108
21.2

29.550
WW-FE3
OS/07/SS


13
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
13J

0.10
0.723
12.9
0.010
0.020
5.47
0.0050
7.31
0.182
1.53
35.2
0.010

34.1
53
0.0579
0.0579
0.010
18.1

21,065
HW-D1
06/07/35


13
1.00
1.00
24
1.00
1.00
1.00
5.7
1.3
U

0.561
0.020
18.9
0.010
0.020
0.823
0.0050
2.82
0.202
1.09
32.8
0.010

41.4
52.2
0.050
0.050
0.0197
18.1

43,233
MW-D2
OS/OI/9S


12
1.00
1.00
38
1.00
1.00
1.00
7.3
2.1
3J

1.02
0.020
20.5
0.010
0.020
1.12
0.0050
3.13
0.142
1.00
29
0.0104

42.4
47.8
0.050
0.050
0.0133
18.7

13.781
MW-D3
M/07/SE


9.S
1.00
1.00
30
1.00
1.00
1.00
6.8
1.6
0

1.14
0.020
17.8
0.010
0.020
1.42
0.0296
2.69
0.186
1.22
29.3
0.0229

40.4
45.7
0.050
0.050
0.010
18.8

17.084 .
MW-D4
OE/07/35


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

7.08
0.142
126
0.0113
0.020
10.9
0.00947
34.9
1.21
2.77
27.6
0.0525

NA
NA
NA
NA
NA
NA

1.985
MW-OS
&M8/3S


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

0.313
0.04
55.5
0.010
0.020
0.794
0.0050
7.38
0.512
1.25
25.1
0.0206

NA
NA
NA
NA
NA
NA

1.908
MW-DS
06/07/36


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

1.25
0.0934
66.8
0.01 U
0.020
2.08
0.0050
12.8
1.02
1.68
28.2
0.0118

NA
NA
NA
NA
NA
NA

1.942
   Notes:
   U > substance not detected; associated value is the reported detection limit
   NA = parameter not analyzed
* Average value of replicate samples
I •= estimated concentration

-------
Table C-2.  Summary of Analytical Data-July
SAMPLE
SUBSTANCE DETECTED
VOCs (mlcrogramsfflter):
Chloroform
1,1-Dichloroethane
cis-1 ,2-Dichloroelhene
trans-1 ,2-Dichloroemene
Tetrachloroethene
1 , 1 , 1 -Trichloroethane
Trichloroethene
Vinyl chloride
Tentatively Identified Compounds (Total)
Metals (milligrams/liter):
Barium
Calcium
Chromium

Iron
Lead
Magnesium
Manganese
Potassium
Sodium
Zinc
Wet Chemistry (milligrams/liter):
Bicarbonate Alkalinity
Chloride
Nitrate/Nitrite Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Sulfate
Total Phospholipld Fatty Acids:
(Average; picomoles/liter)* 	
MW-U1
07/13/95

5.0U
l.OU
3.5
230
1.2
l.OU
l.OU
100
23
3J
0.10U
0.0374
90.8
0.01U
0.02U
0.0784
0.05U
12.6
0.559
l.OU
31.8
0.0198
288
52.8
0.338
0.338
0.01U
16.7
NA
MW-U2
07/12/95

5.0U
l.OU
2.8 -
280
l.OU
l.OU
4.5
160
16
91
0.10U
0.0268
88.8
0.01U
0.02U
0.05U
0.05U
12.3
0.427
l.OU
31
0.0253
278
53.2
0.378
0.05U
0.378
17.1
NA
MW-U3
07/11/95

5.0U
l.OU
3.1
360
1.0
10U
l.OU
280
18
2J
0.155
0.02U
88
0.01U
0.02U
0.184
0.05U
12.5
0.281
l.OU
31.4
0.0268
290
53.2
0.383
0.383
0.01U
16.7
NA
MW-FE1
07/13/95

12
l.OU
l.OU
l.OU
l.OU
1.0U
l.OU
l.OU
l.OU
1U
0.10U
0.241
14.5
0.01U
0.02U
0.41
0.05U
10.8
0.24
1.65
30
0.01U
59.4
52.1
0.05U
0.05U
0.01U
15.6
NA
MW-FE2
07/12/95

5.0U
l.OU
l.OU
l.OU
l.OU
l.OU
t.OU
l.OU
l.OU
61
0.10U
0.522
14.3
0.01U
0.02U
0.252
0.05U
10.2
0.111
1.45
30.9
0.0109
55.6
54
0.05U
0.05U
0.01U
16.1
NA
MW-FE3
07/11/95

9.6
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
1.2
U
0.1U
0.161
15
0.01U
0.02U
0.615
0.05U
11.3
0.312
1.66
30.8
0.0113
63
53.3
0.05U
0.05U
0.01U
14.9
NA
MW-D1
07/13/95

8.4
l.OU
l.OU
2.2
l.OU
l.OU
l.OU
l.OU
l.OU
1U
0.10U
0.0739
22.6
0.01U
0.02U
0.0883
0.05U
7.06
0.243
1.42
30.2
0.0129
84.8
51.8
0.05U
0.05U
0.01U
11.8
NA
MW-D2
07/12/95

24
l.OU
l.OU
3.7
l.OU
l.OU
l.OU
t.OU
l.OU
81
0.17
0.02U
13.7
0.01U
0.02U
0.05U
0.05U
2.87
0.127
l.OU
27.5
0.0115
51.5
48.6
0.05U
0.05U
0.01U
5.7
NA
MW-D3
07/11/95

30
l.OU
1.0U
3.9
l.OU
l.OU
l.OU
l.OU
l.OU
1U
0.107
0.0494
17.6
0.01U
0.02U
0.0571
0.05U
6.18
0.222
1.36
28.8
0.0124
48
51.4
0.05U
0.05U
0.01U
14.2
NA
MVV-D4
07/13/95

5.0U
1.00
l.OU
30
l.OU
l.OU
l.OU
29
l.OU
1U
0.153
0.02U
21.3
0.01U
0.02U
0.174
0.05U
2.96
0.156
1.0U
27.9
0.01U
NA
NA
NA
NA
NA
NA
NA
MVY-DS
07/12/95

44
l.OU
l.OU
50
l.OU
l.OU
l.OU
54
2.2
21
0.10U
0.0246
36
0.01U
0.02U
0.05U
0.05U
4.91
0.312
l.OU
26.7
0.0161
NA
NA
NA
NA
NA
NA
NA
MW-D6
07/11/95

NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.11
0.035
30.2
0.01U
0.02U
0.104
0.05U
4.74
0.516
l.OU
28.2
0.0144
NA
NA
NA
NA
NA
NA :
NA
    Notes:
    U-substance not detected; associated value is detection limit.          * Average value of replicate samples
    NA = parameter not analyzed.                                     J = estimated concentration.
    VOC sample fractions were collected from wells MW-D4 and D5 for lie sole purpose of supporting the demonstration health and safety program, and were not required by the project quality assurance project plan;

      VOC data from these wells are not directly relevant to demonstration objectives.

-------
Tab!ฎ C-3. Summary of Analytical Data-August
SAMPLE
Dtte
SUBSTANCE DETECTED
VOCi (uicroinms/lller):
Acetone
Chloroform
1,1-DkhIotoerhane
ct!-l,2-DichIoroethene
trans-1 ,2-Dichloroethene
Tetrachloroethene
1,1,1-Trichloroethane
Trichloroethene
Vinyl chloride
Tentatively Identified Compounds (Total)
MeUls (milligrams/liter):
Ahiminum
Barium
Calcium
OO ;.! -
O\ Chromium
Copper
Iron
Lead
Magnesium
Manganese
Potassium
Sodium
Zinc
Wet Chemistry (milligrams/liter):
' Bicarbonate Alkalinity
Chloride
Nitrate/Nitrite Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Sulfate
Total Phospholipid Fatty Acids:
(Averager picomoles/liter)*
MW-W
08/01/95


5.0U
l.OU
2.4
180
l.OU
l.OU
4.5
110
8.1
2.0J
0.149
0.0385
86.3
O.OIU
0.02U
0.146
O.OSU
12.2
0.541
2.23
31.4
0.0205
293
54.4
0.277
NA
NA
18.1

NA
MW-UZ
08/09/J5


8
l.OU
2.2
190
l.OU
l.OU
3.8
110
4.7
5.0J
0.145
0.0303
89.8
O.OIU
0.02U
0.166
O.OSU
12.5
0.432
U44
30.2
0.029
293
56.4
0.396
NA
NA
17.2

NA
MW-U3
08/08/95


5.0U
l.OU
3.3
550
2.2
l.OU
6.3
330
21
2.01
0.10U
0.02U
88.8
O.OIU
0.02U
0.0596
O.OSU
12.6
0.321
2.46
32
0.0184
298
54.9
0.34
NA
NA
18

NA
MW-EE1
01/08/95


5.0U
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
0.10U
0.281
9.42
O.OIU
0.02U
0.406
O.OSU
10.3
0.186
1.96
30.5
O.OIU
68.7
55.7
O.OSU
NA
NA
5.0U

NA
01/09/95


8
l.OU
l.OU
1.1
l.OU
l.OU
l.OU
l.OU
l.OU
1.01
0.10U
0.384
10.6
0.01U
0.02U
0.311
O.OSU
9.68
0.118
1.26
29.9
0.0111
59.9
55.7
O.OSU
NA
NA
6.33

NA
MW-I23
08/01/95


7.7
I.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
5.0J
0.10U
0.08
10.4
O.OIU
0.02U
1.16
O.OSU
10.7
0.211
2.18
30.1
0.01U
73.9
55.2
0.05U
NA
NA
5.0U

NA
MW-D1


7.6
l.OU
l.OU
6
l.OU
l.OU
l.OU
3.3
l.OU
2.01
0.109
0.0655
21.9
O.OIU
0.02U
0.108
O.OSU
6.28
0.236
1.6
30.1
0.0127
92.9
54.2
0.053
NA
NA
5.0U

NA
MW-DZ
08/0905


5.0U
l.OU
l.OU
1.6
l.OU
l.OU
l.OU
l.OU
l.OU
3.0J
0.122
0.02U
16.8
0.01U
0.02U
0.10U
O.OSU
4.62
0.267
1.0U
29.8
0.0153
65.6
53.7
0.05U
NA
NA
5.0U

NA
MW-D3
08/08/95


5.0U
1.0U
l.OU
1.9
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
0.11
0.0462
13.9
O.OIU
0.02U
0.088
0.05U
5.23
0.2
1.73
29.6
0.0102
64.3
5C7
O.OSU
NA
NA
5.0U

NA
RW-D4
01/01/JS


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1.12
0.02U
22.4
O.OIU
0.02U
1.48
0.05U
4.06
0.189
1.51
29.4
0.0156
NA
NA
NA
NA
NA
NA

NA
MW-DS


NA
NA
NA
nA
NA
iirt
NA
NA
NA
NA
NA
NA
0.112
0.0281
32.4
O.OIU
0.02U
0.1U
O.OSU
4.76
0.4
1.09
29.1
0.0208
NA
NA
NA
NA
NA
NA


MW-Df


NA
NA
MA
rtrt
MA
n/v
NA
ll/V
MA
li/l
NA

NA
0.506
0.045
24.9
O.OIU
0.02U
0.676
O.OSU
5.01
0.543
1.3
29.8
0.0148
NA
NA
NA
MA
rtn
NA
NA



  Notes:
  U = substance not detected; associated value is detection limit
  NA - parameter not analyzed.
* Average value of replicate samples.
J = estimated value.

-------
         Table C-4. Summary of Analytical Data-October
00
SAMPLE
Date
SUBSTANCE DETECTED
VOCi (mlorograms/liter):
Acetone
Bromodichlorometnane
Chloroform
Chloroemane
1,1-Dichloroethane
1,1-Dichloroethene •
cis-1 ,2-Dichloroethene
trans-1 ,2-Dichloroethene
Methylene Chloride
Tetrachloroethene
1,1,1-Trichloroethane
Toluene
Trichloroethene
Vinyl chloride
Tentatively Identified Compounds (Total)
Metals (milligrams/liter):
Aluminum
Barium
Calcium
Chromium •
Copper
Iron
Lead
Magnesium
Manganese
Potassium'
Sodium
Zinc
Wet Chemistry (milligranu/Uter):
Bicarbonate Alkalinity
Chloride
Nitrate/Nitrite Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Sulfate
Total PboiphoUpld Fatty Adds:
(Average: picomoles/literi* 	
MW-U1
10/11/95


S.OU
l.OU
l.OU
l.OU
3.9
1.1
320
1.7
l.OU
l.OU
5.6
l.OU
120
53
l.OU

0.1U
0.0402
92.1
0.03U
0.02U
0.1U
0.05U
12
0.59
1.99
31.1
0.02U

299
45.4
0.19
0.19
0.01U
15.8

91
MW-TJ2
10/12/95


S.OU
l.OU
l.OU
l.OU
5.4
1.2
450
1.9
l.OU
l.OU
7.7
l.OU
160
79
l.OU

0.1U
0.0305
95.6
0.03U
0.02U
0.1U
0.05U
12.3
0.461
1.78
31.4
0.02U

299
46.4
0.31
0.298
0.0118
15.5

115
. MW-U3
10/11/95


S.OU
l.OU
l.OU
2
5.8
1.2
370
1.9
1.0U
l.OU
7.9
1.0U
ISO
49
l.OU

0.1U
0.02U
88.8
0.01U
0.02U
0.1U
O.OSU
12.6
0.321
2.46
32
0.0184

299
48
0.269
0.269
0.01U
16.7

492
MW-FE1
10/1105


5.0U
l.OU
1.0U
l.OU
1.0U
l.OU
1.2
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
2.5J

0.1U
0.0599
7.72
0.03U
0.02U
0.184
O.OSU
9.01
0.0716
2.22
33.3
0.02U

55.8
47.6
O.OSU
0.05U
0.01U
S.OU

56
MW-FE2
10/12/95


5.0U
l.OU
l.OU
1.0U
l.OU
l.OU
2
l.OU
1.0U
l.OU
l.OU
l.OU
l.OU
l.OU
3.61

0.1U
0.14
9.17
0.03U
0.02U
0.203
0.05U
9.68
0.079
2.17
33.9
0.02U

60
49.5
O.OSU
0.05U
0.01U
S.OU

36
MW-FE3
10/11/95


5.0U
1.0U
l.OU
l.OU
2.2
l.OU
3.8
l.OU
l.OU
l.OU
1.0U
l.OU
1.0U
2.3
3.3J

0.1U
0.02U
9.61
0.03U
0.02U
0.523
O.OSU
10.5
0.0706
2,22
33.1
0.02U

65.7
48.4
O.OSU
O.OSU
0.01U
S.OU

20
MW-D1
10/11/95


5.6
l.OU
1.0U
l.OU
l.OU
1.0U
5
1.0U
1.0U
l.OU
l.OU
l.OU
1.2
1.0U
1.01

0.1U
0.05
21.3
0.03U
0.02U
0.1U
0.05U
5.51
0.231
1.7
32.5
0.02U

77.7
48.7
O.OSU
O.OSU
0.01U
5.0U

438
MW-D2
10/12/95


5.0U
l.OU
l.OU
I.OU
1.0U
l.OU
7.5
1.0U
1.0U
l.OU
l.OU
l.OU
1.5
1.2
l.OU

0.1U
0.02U
15
0.03U
0.02U
0.10U
0.05U
4.25
0.194
1.39
32.8
0.02U

64.7
48.7
0.05U
O.OSU
0.01U
5.0U

325
MW-D3
10/11/95


S.OU
1.0U
1.0U
l.OU
1.0U
l.OU
2
1.0U
I.OU
l.OU
l.OU
l.OU
l.OU
1.0U
1.0U

0.1U
0.0386
15
0.03U
0.02U
0.1U
O.OSU
5.01
0.23
1.72
32.9
0.02U

59.8
49
O.OSU
O.OSU
0.01U
S.OU

245
MW-D4
10/11/95
- -

NA
NA
NA
. NA
NA
NA
NA
NA
NA
NA , .
NA
NA
. . NA ..
.• . NA •..-...
V •- NA , ',

0.17
0.132
64.8 .
0.038.
0.02U
1.16
O.OSU
9.08
1.36
. 1.18
33.5
0.02U

NA
NA
NA
. NA
NA
NA

1.774
MW-D5
10/12/95


NA
. NA
NA
NA
NA
NA
' NA
NA
NA
NA
NA
NA
NA
NA
NA

.0.1U
0.0454
. 28.6
0.03U
0.02U
0:233
O.OSU
4.4
0,719
1.05
33
0.02U

NA
NA
NA
NA
NA
NA

602
MW-D6
10/11/95


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
. . NA

0.712
0.0258
30.2
0.03U
0.02U
0.541
O.OSU
5.16
0.321
1.52
34.8
0.02U

NA
NA
NA
NA
NA
NA

S65
           Notes:
           U - jubilance not detected.
           NA - parameter not analyzed.
* Average value of replicate samples.
Jซ estimated value.

-------
Table C~5. Sutnmaiy of Analyical Data-November
SAMPLE
Dปte
SUBSTANCE DETECTED
VOCs (mfcropims/Iler)!
Acetone
Brotnodichioromethaffle
Chloroform
Chloroethane
l.l-Dichloroethane
1,1-Dichloroelheiie
cis-l,2-Dichloroethene
tran5-l,2-DichIoroe those
Methylene Chloride
Tetrachloroettiene
1 , 1 , 1-TricMoroethane
Toluene
Tiichloroediene
Vinyl chloride
Tentatively Identified Compounds (Total)
Metals (milligrams/liter):
22 Aluminum
OO
Barium
Calcium
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Potassium
Sodium
Zinc
Wet Chemistry (milligrams/liter):
Bicarbonate Alkalinity
Chloride
Nitrate/Nitrite Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Sulfatc
Total Pbosphollpid Fatty Adds:
(Average: oicomoles/Iiter)*
MW4J1
iimns


5.0U
I.OU
I.OU
I.OU
1.1
I.OU
98
I.OU
I.OU
I.OU
3.3
I.OU
32
7.9
8.01

0.2U
0.0342
87.5
0.01U
0.02U
0.165
O.OSU
11.9
0.468
1.65
28
0.02U

259
40.8
0.125
0.11
0.153
13.1

NA
MWJUZ
1UWK


5.0U
I.OU
I.OU
I.OU
1.8
I.OU
140
I.OU
I.OU
I.OU
4.4
I.OU
65
10
8.41

0.2U
0.0284
89.9
0.01U
0.02U
0.0728
0.05U
11.9
0.345
1.75
27.7
0.02U

272
42.5
0.175
0.157
0.018
14.4

NA
MW-U3
HAMS


5.0U
I.OU
1.0U
I.OU
Z7
I.OU
240
1.9
I.OU
I.OU
6.9
I.OU
110
25
7.1J

0.2U
0.02U
89.9
0.01U
0.02U
0.0506
O.OSU
12
0.269
1.49
28.7
0.02U

283
43.8
0.19
0.171
0.0192
15.3

NA
Mw-m
U/09/JS


5.0U
I.OU
1.0U
I.OU
I.OU
I.OU
1.04
I.OU
.ou
.ou
.ou
.ou
.ou
.ou
4.3J

0.2U
0.0492
8.12
0.01U
0.02U
0.144
O.OSU
8.38
0.0534
2.01
27.7
0.02U

41.8
43.6
0.05U
O.OSU
0.01U
5.0U

NA
Mw-m
WOU9S


5.0U
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
2.0J

0.2U
0.0974
7.96
0.01U
0.02U
0.2
O.OSU
8.06
0.0598
1.86
28.2
0.02U

44.3
45.8
O.OSU
O.OSU
0.01U
5.0U

NA
MW-FE3
U/W95


5.0U
I.OU
I.OU
I.OU
3.9
I.OU
IS
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
1.6
3.81

0.2U
0.02U
8.88
0.01U
0.02U
0.506
O.OSU
10.3
0.0453
1.93
28.1
0.02U

50.3
42.6
O.OSU
0.03U
0.01U
5.0U

NA
MW-D1
UflWS


5.0U
I.OU
I.OU
I.OU
I.OU
I.OU
4.6
I.OU
I.OU
I.OU
I.OU
I.OU
1.6
I.OU
I.OU

0.2U
0.0422
20.3
0.01U
0.02U
0.134
O.OSU
4.76
0.161
1.23
23.7
0.02U

55.5
37.6
O.OSU
O.OSU
0.01U
5.0U

NA
MW-B2
1WWS


5.0U
I.OU
I.OU
I.OU
I.OU
I.OU
4.2
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU
2.01

0.2U
0.02U
13.4
0.01U
0.02U
0.0862
O.OSU
3.72
0.161
1.27
23.2
0.02U

63.7
37.9
O.OSU
O.OSU
0.01U
5.0U

NA
MW-B3
_J1/OOT5


8
I.OU
I.OU
I.OU
I.OU
I.OU
2.8
I.OU
1.3
I.OU
I.OU
I.OU
I.OU
I.OU
I.OU

0.02U
0.0341
10.3
0.01U
0.02U
0.134
0.05U
4.27
0.0733
1.4
22J
0.02U

48.8
38.7
O.OSU
0.05U
0.01U
S.OU

NA
MW-D4
U/09/JS


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

0.735
0.0275
33.3
0.01U
0.02U
1.1
O.OSU
5.58
0.34
1.26
21.1
0.02U

NA
NA
NA
NA
NA
NA

NA
MW-D5
11/IW95


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

0.2U
0.0333
30.3
0.01U
0.02U
0.211
O.OSU
4.56
0.452
I.OU
22.1
0.02U

NA
NA
NA
NA
NA
NA

NA
MW-DC
1I/W95


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

0.435
0.0572
39.3
0.01U
0.02U
0.498
O.OSU
6.72
0.521
1.38
24.8
0.02U

NA
NA
NA
NA
NA
NA

NA
  Notes:
  U - substance not detected; associated value is detection limit
  NA = parameter not analyzed.
* Average value of replicate samples.
J fs estimated value.

-------
Table C-6.  Summary of Analytical Data-December
SAMPLE
Date
SUBSTANCE DETECTED
VOCs (micrograms/liter):
Acetone
Bromodichloromethane
Chloroform
Chloroemane
1,1-Dichloroethane
1,1-Dichloroethene
eis-1 ,2-Dicbloroethene
trans-l,2-Dichloroethene
Methylene Chloride
Tetrachloroethene
1,1, 1-Trichloroethane
Toluene
Trichloroethene
Vinyl chloride
Tentatively Identified Compounds (Total)
, Metals (milligrams/liter):
OO Aluminum
VO
Barium
Calcium
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Potassium
Silver
Sodium
Zinc
Wet Chemistry (milligrams/liter):
Bicarbonate Alkalinity
Chloride
Nitrate/Nitrite Nitrogen
Nitrate Nitrogen
Nitrite Nitrogen
Sulfate
Total PhosphoUpid Fatty Adds:
(Average; nicomoles/liter)*
MW-UI
12/05/95


5.0U
l.OU
l.OU
l.OU
3.4
l.OU
180
l.OU
l.OU
1.0U
13
l.OU
110
21
4.1J

0.2U
0.0387
92.5
0.01U
0.02U
0.1U
0.05U
12.9
0.494
1.87
0.01U
30.5
0.0129

311
47.2
0.23
0.2
0.0299
16.3

19
MW-U2
12/06/95


5.0U
l.OU
l.OU
l.OU
3.6
l.OU
240
l.OU
l.OU
l.OU
11
l.OU
120
22
3.6J

0.2U
0.0252
90.6
0.01U
0.02U
0.1U
0.05U
12.7
0.388
1.93
0.01U
29.4
0.0119

291
47.4
0.269
0.238
0.0305
17.2

66
MW-U3
12/05/95


5.0U
l.OU
l.OU
l.OU
3.9
1.0U
270
l.OU
l.OU
l.OU
13
l.OU
130
22
4.4J

0.2U
0.02U
90.7
0.01U
0.02U
0.1U
0.05U
12.9
0.289
1.97
0.01U
30.3
0.0125

293
48
0.19
0.169
0.0209
16.3

54
MW-FE1
12/05/95


5.0U
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
i.OU
l.OU
2.01

0.2U
0.0474
12.7
0.01U
0.02U
0.238
0.05U
10.4
0.0958
2.11
0.01U
29.9
0.01U

9.95
48.3
0.05U
0.05U
0.01U
5.0U

10
MW-FE2
12/06/95


5.0U
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
l.OU
3.2J

0.2U
0.102
9.6
0.01U
0.02U
0.158
0.05U
7.33
0.0574
1.86
0.01U
29.6
0.01U

47.8
49.2
0.05U
0.05U
0.01U
5.0U

72
MW-FE3
12/05/95


5.0U
1.0U
l.OU
l.OU
2.7
l.OU
4.3
l.OU
1.0U
l.OU
1.0U
l.OU
l.OU
4.1
3.21

0.2U
0.02U
9.98
0.01U
0.02U
0.601
0.05U
8.29
0.128
1.5
0.01U
28.6
0.01U

43.8
48.6
0.05U
0.05U
0.01U
5.0U

114
MW-D1
12/05/95


5.0U
l.OU
l.OU
l.OU
l.OU
l.OU
2.5
l.OU
.OU
.OU
.OU
.OU
.OU
.OU
1.3J

0.2U
0.0363
21
0.01U
0.02U
0.148
0.05U
5.5
0.16
1.47
0.01U
26.5
0.01U

75.7
45.3
0.05U
0.05U
0.01U
5.0U

1,005
MW-D2
12/06/95


5.0U
l.OU
l.OU
l.OU
l.OU
l.OU
5.6
l.OU
l.OU
l.OU
l.OU
l.OU
0.911
l.OU
6.21

0.2U
0.02U
15.4
0.01U
0.02U
0.1U
0.05U
4.23
0.195
1.02
0.01U
23.4
0.01U

56.5
42.8
O.OSU
0.05U
0.01U
5.0U

1,508
MW-D3
12/05/95


5.0U
l.OU
l.OU
l.OU
l.OU
l.OU
5.4
l.OU
l.OU
1.0U
1.0U
l.OU
l.OU
l.OU
1.0U

0.02U
0.0411
16.6
0.01U
0.02U
0.128
O.OSU
6.65
0.238
1.78
0.01U
27.1
0.01U

61.8
45.8
O.OSU
0.05U
0.01U
5.0U

1,601
MW-D4
12/05/95


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

0.325
0.0231
28.5
0.01U
0.02U
0.554
O.OSU
4.96
0.318
1.16
0.01U
20
0.0114

NA
NA
NA
NA
NA
NA

2,480
MW-D5
12/06/95


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

0.2U
0.0338
33.6
0.01U
0.02U
0.159
O.OSU
5.95
0.174
l.OU
0.01U
15.5
0.0115

NA
NA
NA
NA
NA
NA

3.450
MW-D6
12/05/95


NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA

0.974
0.0578
43.8
0.01U
0.02U
1.06
O.OSU
8.47
0.377
1.23
0.01U
23.9
0.014

NA
NA
NA
NA
NA
NA

2,482
     Notes:
     U - substance not detected; associated value is detection limit.
     NA = parameter not analyzed.
I a estimated concentration; reported value is below PQL.
* Average value of replicate samples.

-------

-------

-------
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-------