U.S. EPA Contaminated Site Cleanup Information (CLU-IN)


U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Permeable Reactive Barriers, Permeable Treatment Zones, and Application of Zero-Valent Iron

Application

This section is arranged in three parts. The first contains documents that describe/examine PRBs for multiple sites. The second section contains individual sites with PRB cleanup directed at inorganic contaminants. The third section contains individual sites with PRB cleanup directed at organic contaminants.


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Multiple Sites | Inorganics | Organics

Multiple Sites

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Inorganics

Handbook of Groundwater Remediation Using Permeable Reactive Barriers: Applications to Radionuclides, Trace Metals, and Nutrients
Naftz, David, et al. (eds.). Academic Press, San Diego, CA. ISBN: 0125135637, 550 pp, 2002

This handbook offers numerous case studies to introduce the reader to current applications, innovations, and methods for using PRBs in the removal of inorganic contaminants from groundwater.

Mine Waste Technology Program: Permeable Treatment Wall Effectiveness Monitoring Project, Nevada Stewart Mine
McCloskey, A.L.
EPA 600-R-06-153, 100 pp (plus appendices A-F, 282 pp), 2007

This project demonstrates the effectiveness of Apatite II™ (cleaned fishbone) to remove metals (zinc, iron, manganese, lead, and cadmium) from water flowing from a mining site.

Arsenic

Adobe PDF LogoField Application of a Permeable Reactive Barrier for Treatment of Arsenic in Ground Water
Wilkin, R.T., S.D. Acree, D.G. Beak, R.R. Ross, T.R. Lee, and C.J. Paul.
EPA 600-R-08-093, 81 pp, 2008

In June 2005, a pilot-scale PRB containing granular iron was installed at a former metal smelting facility near Helena, MT, to treat ground water contaminated with concentrations (>25 mg/L) of arsenite and arsenate. The barrier is 9.1 m long, 14 m deep, and 1.8 to 2.4 m wide (in the direction of ground-water flow). Within the PRB, As concentrations are 2 to <0.01 mg/L. After 2 years of operation, significant decreases in As concentrations are evident. This report covers site characterization, remedial design and implementation, and monitoring results for this pilot-scale PRB. Additional information: (Wilkin et al. 2009, Abstract)

Adobe PDF LogoField Demonstration of Zerovalent Iron Treatment Technology in Parker Brothers Arroyo: Status Report
Texas Custodial Trust, El Paso, 94 pp, 2014

Environmental impacts from historical smelting operations are present within and outside the site of the former ASARCO smelter (El Paso, Texas). In Parker Brothers Arroyo, the site contractor completed construction of two in situ ZVI-based PRBs in October 2012 and the performance monitoring network in June 2013. This status report presents construction details for the PRBs with subsequent performance results. The objectives of the field demonstration are to verify the effectiveness of the ZVI PRB technology for concentrations of As, Sb, Se, and thallium above regulatory requirements at this site, initiate groundwater remediation, and provide data to support the final site-wide groundwater remedy. Additional information: Other Technical Reports.

Adobe PDF LogoPermeable Reactive Barriers for Treatment of As-Contaminated Groundwater (PPT)
Bain, J., David Blowes, and John Wilkens
Sudbury 2007 Mining and the Environment

This PPT presentation discusses using basic oxygen furnace (BOF) slag as a permeable reactive barrier fill material for the treatment of arsenic. It concludes that PRBs composed of BOF slag and mixtures of ZVI with organics are effective for the treatment of arsenic in groundwater in a variety of environments.

Chromium

In Situ Permeable Reactive Barrier for Treatment of Contaminated Groundwater at the U.S. Coast Guard Support Center, Elizabeth City, North Carolina (1998)

The PRB used at this site consists of 450 tons of granular zero-valent iron keyed into an underlying low conductivity layer at a depth of approximately 22 ft bgs. The required residence time in the treatment zone has been estimated as 21 hours, based on a highest concentration scenario. The average velocity through the wall was reported as 0.2 to 0.4 ft/day. Analytical data from the first year of full-scale operation show that the cleanup goal for Cr+6 has been met, but not the goal for TCE. Several possible reasons are provided for the elevated TCE levels.

Adobe PDF LogoAn In Situ Permeable Reactive Barrier for the Treatment of Hexavalent Chromium and Trichloroethylene in Ground Water
Blowes, D.W. et al.
EPA 600-R-99-095a, EPA 600-R-99-095b, and EPA 600-R-99-095c, 1999

A 46 m long, 7.3 m deep, and 0.6 m wide permeable subsurface reactive wall was installed at the U.S. Coast Guard (USCG) Support Center, near Elizabeth City, North Carolina, in June 1996. The reactive wall was designed to remediate hexavalent chromium [Cr(VI)] contaminated groundwater at the site, in addition to treating portions of a larger overlapping trichloroethylene (TCE) groundwater plume which had not yet been fully characterized.

  • Volume 1: Design and Installation Adobe PDF Logo
    The site preparation, trenching installation, follow-up soil treatment, and overall project costs, using the selected reactive material and barrier configuration are described.
  • Volume 2: Performance Monitoring Adobe PDF Logo
    This volume describes activities undertaken to monitor the barrier performance over a 2 year period. The results of the monitoring are reported.
  • Volume 3: Multicomponent Reactive Transport Modeling Adobe PDF Logo
    Reactive transport modeling was conducted to describe the performance of the permeable reactive barrier at the U.S. Coast Guard Support Center near Elizabeth City, N.C. The multicomponent reactive transport model MIN3P was used for the simulations. The essential reactions contained in the conceptual model are aqueous complexation reactions, combined reduction-corrosion reactions between the treatment material zero-valent iron and the contaminants or other electron acceptors dissolved in the ambient groundwater and the precipitation of secondary minerals within the reactive barrier. The model results provide estimates of the potential effects of the consumption of zero-valent iron and the precipitation of secondary minerals on the long-term efficiency of the treatment system.

General Metals

Adobe PDF LogoA Permeable Reactive Barrier for Treatment of Heavy Metals
Ludwig, R. et al.
Ground Water, Vol 40, No 1 p 59-66, 2002

This paper describes a pilot application of a compost based permeable reactive barrier to treat acidic mine sulfide mineral affected groundwater (Cu, Cd, Co, Ni, and Zn). The barrier uses sulfate reducing bacteria to promote the precipitation of heavy metals as insoluble metal sulfides.

Strontium

Adobe PDF Logo100-NR-2 Apatite Treatability Test: High-Concentration Calcium-Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization
Vermeul, V.R., B.G. Fritz, J.S. Fruchter, J.E. Szecsody, and M.D. Williams.
PNNL-19572, 134 pp, 2010

An injectable PRB technology was developed at DOE's Hanford facility to sequester Sr-90 in groundwater through the in situ formation of calcium-phosphate mineral phases, specifically apatite, which incorporates Sr-90 into the chemical structure. The 300-ft treatability-test PRB was installed in 2008 on the downgradient edge of a Sr-90 plume beneath the Hanford site to reduce Sr-90 flux discharging to the Columbia River.

Geochemical Characterization and Longevity Estimates of a Permeable Reactive Barrier System Remediating a 90Sr Plume
Hoppe, Jutta, Master's thesis, University of Waterloo, Waterloo, ON, Canada, 144 pp, 2012

In 1998, a "wall and curtain" PRB containing clinoptilolite was installed at the Chalk River Laboratories in Chalk River, Ontario, to prevent the discharge of a strontium-90 plume into a nearby swamp. After nearly 14 years of operation, refined estimates of the PRB's efficiency and longevity indicate the system is highly efficient in treating an average mass flux of >17,000 Bq/m2/day and could continue to function for 80 to 100 years.

Treatment Wall for Groundwater Mitigation at the West Valley Demonstration Project (WVDP)

An 850-ft-long trench filled with 2,000 tons of a reactive medium is being used to remove radioactive Sr-90 from the groundwater at the WVDP in New York State . The contamination originated from a leak in a process line during commercial nuclear fuel reprocessing (1966-1972). The treatment wall promotes ion exchange, chiefly by means of the zeolite mineral clinoptilolite in which the divalent Sr-90 replaces the monovalent cation of potassium or sodium within the mineral's lattice structure. First conceived as a pilot in the late 1990s, full-scale installation was completed by the end of 2010 using $8M in American Recovery and Reinvestment Act funding. Resources:

Uranium

Design, Construction, and Monitoring of a Permeable Reactive Barrier Technology for Use at Rocky Flats Environmental Technology Site (RFETS)
Dwyer, Brian P., Sandia National Labs., Albuquerque, NM, Report No: SAND2000-2702. NTIS: DE00767720. 65 pp, 2000

This report describes the testing of three reactive media: high carbon steel iron filings, an iron-silica alloy in the form of a foam aggregate, and a pellicular humic acid based sorbent mixed with sand to remediate groundwater containing uranium, TCE, PCE, carbon tetrachloride, americium, and vinyl chloride. The iron filings were chosen and a PRB was constructed at the 903 Mound Site Plume. The treatment system began full operation in December, 1998 and despite a few problems has been operational since. Results to date show complete removal of the contaminants of concern (COCS) prior to discharge to meet project requirements.

Fry Canyon, UT, USGS Project Home Page

Three different PRBs were installed at the demonstration site in 1997, respectively containing Cercona Bone Char Phosphate, Cercona foamed ZVI pellets, and amorphous ferric oxide. The project will utilize geochemical and hydrologic approaches to assess the performance of the PRBs toward the long-term remediation of the Fry Canyon tailings site.

Adobe PDF LogoPerformance Assessment and Recommendations for Rejuvenation of a Permeable Reactive Barrier: Cotter Corporation's Canyon City, Colorado, Uranium Mill
DOE-LM/GJ816-2005, ESL-RPT-2005-02, 130 pp, 2005

A ZVI PRB was installed in 2000 to treat molybdenum and uranium at the currently operating Cotter Corporation mill site. Though the barrier eventually failed for Mo, U concentrations remained at less than 0.006 mg/L. The ZVI became clogged by mineral precipitants, and modifications (e.g., a pretreatment zone composed of coarse gravel and ZVI) were suggested. Given the conditions experienced at the PRB in 2003, Cotter evaluated the system at years' end and subsequently initiated pumping of upgradient groundwater to the site's primary impoundment.

Permeable Reactive Barrier Facility at the Bodo Canyon Disposal Cell, Durango, Colorado
U.S. DOE, Office of Legacy Management, Grand Junction, CO.

A PRB facility was constructed at the Durango, Colorado, Disposal Site in 1995 to test PRB designs for passive remediation of uranium-contaminated groundwater via treatment of contaminated tailings water (leachate) issuing from a seep into a subsurface engineered collection gallery and drained by gravity to a lined retention basin for treatment at the site's downgradient boundary. Several PRBs (ZVI, copper wool, and steel wool) were used to treat As, Mo, Se, U, V, and Zn. The ZVI barrier operated from August 1999 until June 2004, when flow ceased from the seep and remediation was no longer needed. It maintained effluent uranium concentrations of less than 0.01 mg/L, and was highly effective in treating contaminants.

Further Documentation

Permeable Reactive Barrier at the Monticello Mill Tailings Site, Monticello, Utah
U.S. DOE, Office of Legacy Management, Grand Junction, CO.

In 1999, DOE installed a ZVI-containing PRB downgradient of the former uranium milling site at Monticello, UT. The PRB has been effective in reducing concentrations of As, Se, U, and V to nondetectable levels on the PRB's downgradient side, and Mo and nitrate to near nondetect. Soil-bentonite slurry walls direct groundwater to the PRB, but some contaminated groundwater is flowing around the south slurry wall. Methods that might be used to mend the gap on the south end of the slurry wall were investigated. There has been some evidence of barrier clogging, and chemical flushing of the barrier to remedy the clogging was investigated. In 2005, a supplemental treatment cell containing a mixture of ZVI and gravel was installed at the site.

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Organics

Chlorinated Solvents

Adobe PDF LogoA-Zone Aquifer ZVI Permeable Reactive Barrier Project, Hookston Station Site, Pleasant Hill, California: Final Construction Report
GeoSierra Environmental, Inc.
California Regional Water Quality Control Board, San Francisco Bay Region. 45 pp, Sep 2009

An iron PRB was installed in 2009 at an off-site location near the Hookston Station site to degrade TCE, cis-1,2-DCE, VC, and 1,1-DCE in site groundwater and limit their migration downgradient. Constructed using azimuth-controlled vertical hydrofracturing technology, the PRB consists of one continuous reactive zone of ZVI ~480 feet in length and ~32 feet in vertical height.

Allegany Ballistics Laboratory (US Navy), Mineral County, West Virginia Superfund Site

The PRB at this Superfund site consists of a wall of reactive media (zero valent iron) approximately 200 feet in length, 2 feet in width, and 17 feet in depth installed through the alluvial aquifer and keyed into the bedrock. The remedy for Site 5 (OU-2) was initiated in April 2006 and completed in June 2006. The contaminant of concern is TCE.

The Biogeochemical Reductive Dehalogenation Groundwater Treatment Process: Commercialization Status at Bench, Pilot and Full Scale
Studer, J.E.
Abstracts of the 21 st Annual Florida Remediation Conference, Orlando, October 8-9, 2015

A novel in situ remediation technology that combines biological and abiotic processes has been commercialized as the BiRD biogeochemical reductive dehalogenation treatment process. The technology generates amorphous and crystalline forms of iron sulfide (referred to as FexSy) in situ, which can dehalogenate compounds such as PCE, TCE, and other chlorinated aliphatics at significant rates. The FexSy reactive zone is created rapidly and can treat passing groundwater over a relatively long period of time. The process can be applied via direct injection or trenching techniques using inexpensive nontoxic reactants that are readily available in either liquid or solid form. The technology is compatible with enhanced bioremediation and zero-valent iron treatments. Additional information: Presentations to the California State Water Resources Control Board Adobe PDF Logo.

Contamination Movement around a Permeable Reactive Barrier at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina, 2009
Vroblesky, D.A., M.D. Petkewich, and K.J. Conlon.
U.S. Geological Survey Scientific Investigations Report 2010-5086, 84 pp, 2010

Chlorinated VOC (PCE, 1,1,1-TCA, TCE, cDCE, VC, 1,1-DCE, 1,2-DCA, and 1,1-DCA) groundwater contamination SWMU 12 at the Naval Weapons Station Charleston, SC, is being addressed in part by a ZVI PRB 130 ft long and 3 ft wide installed in December 2002. In early 2004, groundwater contaminants began moving around the southern end of the PRB. USGS is monitoring and documenting the interaction of PRB and groundwater. Additional information: 2004-2006 Report; 2006-2007 Report; 2008 Report

Design, Construction and Monitoring of a Permeable Reactive Barrier Technology for Use at Rocky Flats Environmental Technology Site (RFETS)
Dwyer, Brian P., Sandia National Labs., Albuquerque, NM, Report No: SAND2000-2702. NTIS: DE00767720. 65 pp, 2000

This report describes the testing of three reactive media: high carbon steel iron filings, an iron-silica alloy in the form of a foam aggregate, and a pellicular humic acid based sorbent mixed with sand to remediate groundwater containing uranium, TCE, PCE, carbon tetrachloride, americium, and vinyl chloride. The iron filings were chosen and a PRB was constructed at the 903 Mound Site Plume. The treatment system began full operation in December, 1998 and despite a few problems has been operational since. Results to date show complete removal of the contaminants of concern (COCS) prior to discharge to meet project requirements.

Adobe PDF LogoDesign, Construction, and Monitoring of the Permeable Reactive Barrier in Area 5 at Dover Air Force Base
Gavaskar, Arun; Neeraj Gupta; Bruce Sass; Woong-Sang Yoon; Robert Janosy, Battelle, Columbus, OH. Report No: AFRL-ML-WP-TR-2000-4546. NTIS: ADA380005. 399 pp, 2000

The primary objective of this project was to test the performance of two different reactive media in the same aquifer. The PRB was installed in Area 5 at Dover Air Force Base, DE in December 1997 to treat a PCE plume and was monitored over 18 months of operation. The PRB is a funnel-and-gate system with two gates. Both gates contain granular iron as the reactive medium and were installed with the use of caissons. Gate 1 had a pretreatment zone (PTZ) consisting of 10% iron and sand, and Gate 2 had a PTZ consisting of 10% pyrite and sand. The PTZs were designed to remove dissolved oxygen before it entered the 100% iron reactive cell. The pyrite PTZ had the proposed benefit of pH control. However, monitoring showed that the reduced pH in the pyrite PTZ could not be sustained in the 100% iron reactive cell. The PRB is functioning as designed in terms of chlorinated solvent reduction, hydraulic performance, and geochemistry. The use of caissons was found to be a viable method for installing a PRB in the midst of several utility lines and in a relatively deep aquifer.

Adobe PDF LogoEvaluating Long-Term Impacts of Soil-Mixing Source-Zone Treatment Using Cryogenic Core Collection
Olson, M., W. Clayton, T. Sale, S. De Long, M. Irianni-Renno, and R. Johnson.
ESTCP Project ER-201587, 232 pp, 2017

This project focused on DNAPL source zone remediation using soil mixing with ZVI and bentonite, a technology referred to as ZVI-clay soil mixing. In November 2012, the soil mixing technology was implemented in a TCE DNAPL source zone at Site 17, Naval Support Facility Indian Head, MD. Four years of remediation performance data indicate that TCE concentrations in soil and groundwater within the treated-soil zone had been reduced by up to four and five orders of magnitude, respectively. Groundwater concentrations in portions of the former-DNAPL source-zone approached MCLs within four years of soil-mixing completion. To assess post-remediation potential for TCE concentrations to rebound, as well as effects of remediation on natural fate and transport processes, high-resolution data representing both high-permeability and low-permeability soil strata were collected using cryogenic core collection.

F.E. Warren Air Force Base, Cheyenne, Wyoming Superfund Site

As part of the groundwater remedy at this Superfund site, a three-section PRB wall was designed for the upper 15 feet of the aquifer at SS7 to minimize the TCE concentrations reaching Diamond Creek. Construction of the PRB wall was completed in September 1999 and included installation of an array of monitoring wells upgradient, within and downgradient of the PRB. Monitoring of the groundwater in these wells has been ongoing and indicates that the PRB wall has reduced the concentration of TCE in groundwater on the downgradient side of the PRB.

Adobe PDF LogoIn Situ Chemical Reduction (ISCR) Technologies: Significance of Low eH Reactions
Dolfing, J., M. Van Eekert, A. Seech, J. Vogan, and J. Muellers.
Soil & Sediment Contamination, Vol 17 No 1, p 63-74, Jan 2008

In March 2005, 22,000 kg of ISCR reagent was injected to form an 82-m PRB across a plume of dissolved-phase carbon tetrachloride (CT) about 150 m downgradient of the suspected source area. The ISCR reagent slurry was injected at 126 injection points advanced via direct push. By August 2006, CT concentrations had decreased from > 1,600 ppb to < 5 ppb, achieving > 99% removal.

Adobe PDF LogoAn In Situ Permeable Reactive Barrier for the Treatment of Hexavalent Chromium and Trichloroethylene in Ground Water
Blowes, D.W. et al.
EPA 600-R-99-095a, EPA 600-R-99-095b, and EPA 600-R-99-095c, 1999

A 46 m long, 7.3 m deep, and 0.6 m wide permeable subsurface reactive wall was installed at the U.S. Coast Guard (USCG) Support Center, near Elizabeth City, North Carolina, in June 1996. The reactive wall was designed to remediate hexavalent chromium [Cr(VI)] contaminated groundwater at the site, in addition to treating portions of a larger overlapping trichloroethylene (TCE) groundwater plume which had not yet been fully characterized.

  • Volume 1: Design and Installation Adobe PDF Logo
    The site preparation, trenching installation, follow-up soil treatment, and overall project costs, using the selected reactive material and barrier configuration are described.
  • Volume 2: Performance Monitoring Adobe PDF Logo
    This volume describes activities undertaken to monitor the barrier performance over a 2 year period. The results of the monitoring are reported.
  • Volume 3: Multicomponent Reactive Transport Modeling Adobe PDF Logo
    Reactive transport modeling was conducted to describe the performance of the permeable reactive barrier at the U.S. Coast Guard Support Center near Elizabeth City, N.C. The multicomponent reactive transport model MIN3P was used for the simulations. The essential reactions contained in the conceptual model are aqueous complexation reactions, combined reduction-corrosion reactions between the treatment material zero-valent iron and the contaminants or other electron acceptors dissolved in the ambient groundwater and the precipitation of secondary minerals within the reactive barrier. The model results provide estimates of the potential effects of the consumption of zero-valent iron and the precipitation of secondary minerals on the long-term efficiency of the treatment system.

Moffett Field

Adobe PDF LogoPermeable Reactive Barrier Cost and Performance Report
Naval Facilities Engineering Service Center.
TR-NAVFAC-ESC-EV-1207, 85 pp, 2012

A cost and performance evaluation of three full-scale PRBs installed at Navy sites also considered the remedy footprint for each PRB, using SiteWise(tm) to assess energy consumption, water consumption, generation of criteria air pollutants, and other metrics. The PRBs represent a range of installation techniques, reactive media, and target contaminants: (1) Granular-scale ZVI trench placement at NWIRP Dallas, Texas, for TCE and Cr(VI); (2) Mulch/vegetable oil biowall rock trencher installation at NWIRP McGregor, Texas, for perchlorate and TCE; and (3) Micro-scale ZVI pneumatic fracturing injection at Hunters Point Naval Shipyard, San Francisco, for chloroform and TCE.

Adobe PDF LogoPermeable Reactive Barrier Downgradient of the Southern Source Area, Former Tecumseh Products Company Site, Tecumseh, Michigan: Construction Documentation Report
U.S. EPA Region 5, 148 pp, 2012

The PRB was installed in May 2011. Site COCs include chlorinated VOCs (mainly TCE, TCA, and daughter products), SVOCs, 1,4-dioxane, metals, cyanide, and PCBs. Where the target treatment zone is relatively shallow, the design called for in situ soil blending to deliver DARAMEND(r) (a pelletized form of controlled-release carbon and ZVI) to the subsurface. The design included the use of injections to deliver ABC(r)+ (a patented mixture of ethyl lactate and glycerin, plus ZVI) to portions of the PRB farther beneath ground surface. ABC(r)+ also was used for shallow injections around an existing sewer pipe. Additional resources: Tecumseh website .

Adobe PDF LogoPermeable Reactive Wall Remediation of Chlorinated Hydrocarbons in Groundwater: ESTCP Cost and Performance Report (CU-9604)
1999, ESTCP

This document provides a brief account of the technology evaluation of a pilot-scale permeable reactive barrier that was installed at Moffett Field in April 1996. The objective was to capture and treat a small portion of the West Side Plume that contains chlorinated volatile organic compound (CVOC) contaminants, primarily trichloroethene (TCE), cis-1,2-dichloroethene (cis-1,2-DCE), and perchloroethene (PCE). The reactive cell in the funnel-and-gate type barrier is composed of granular zero-valent iron. The flowthrough thickness of the reactive cell is 6 ft and it is lined on either side by 2 ft of pea gravel. The reactive cell and pea gravel comprise the gate, which is 10 ft-long and is flanked on each side by 20-foot long funnel walls. There were no indications during the 16 months of operation of any decline in the reactivity or hydraulic performance of the barrier.

Remediation of Contaminated Groundwater Using Permeable Reactive Barriers (RESET)
Tuominen, S., T. Nysten, and J. Reinikainen.
Finnish Environment Institute website, 2014

The long-term performance of a pilot-scale PRB installed at the Orivesi (Finland) field site has been monitored since summer 2006 to evaluate the performance of the granular iron barrier in addressing chlorinated solvents (PCE, TCE, and their degradation products) released to the subsurface by a dry cleaner. The system has a funnel-and-gate configuration with an additional control well. Traditional open pit and cleat-supported excavation techniques were essentially the only available earthwork methods for barrier installation. The fracture zones in bedrock were filled with injection material to eliminate contaminated groundwater bypass below the PRB.

Adobe PDF LogoReport for Full-Scale Mulch Wall Treatment of Chlorinated Hydrocarbon-Impacted Groundwater: Offutt Air Force Base, Nebraska Building 301
Groundwater Services, Inc., Houston, TX. DTIC: ADA422621, 97 pp, 2004.

This report describes the construction of a mulch barrier wall to treat chlorinated solvents (e.g., TCE). The report also describes performance monitoring results and concludes the wall is functioning as designed. There also is a recommendations and lessons learned section

Creosote

Moss-American Site, Milwaukee, Wisconsin Superfund Site

The Moss-American Site, located in Milwaukee, Wisconsin, is approximately 88 acres in size, and consists of a former wood preserving facility, portions of the Little Menomonee River, and adjacent flood plain soils. The biotreatment funnel and gate system consists of six treatment gates, with Waterloo sheet piling located on both sides of the gates to direct groundwater flow. Operation of the system began in October 2000, with the injection of air, followed by the addition of nutrients in Gate 1 in June 2001. In addition, sumps are being used to collect any free product prior to its entering the treatment gate.

The 2005 five-year review noted that very good contaminant removal efficiency was occurring at upgradient treatment gates within the funnel and gate system (TG 1 and TG2). However, the 2005 review found that little beneficial treatment was occurring at two or more downgradient pairs of treatment gates (TG3 and TG4). It concluded that there was a pocket of contaminatlon downgradient of the first pair of treatment gates where flow conditions were nearly stagnant. The 2010 Five Year Review concludes that the downgradient funnel and gate systerm may not be optimally operating.

Explosives

Adobe PDF LogoPassive Biobarrier for Treating Co-mingled Perchlorate and RDX in Groundwater at an Active Range
Hatzinger, P.B. and M.E. Fuller.
ESTCP Project ER-201028, 225 pp, 2016

A field demonstration was undertaken to investigate the performance of a passive emulsified oil biobarrier (EOS 550LS plus CoBupH, a slow-release buffering agent) to remediate commingled perchlorate, RDX, and HMX in the naturally acidic groundwater at the Naval Surface Warfare Center, Dahlgren (Virginia). Perchlorate degraded most quickly and HMX most slowly. After the second injection of emulsified oil, concentrations of RDX, HMX, and perchlorate fell by ≥92% in the centerline of monitoring wells extending 40 ft downgradient of the biobarrier. Accumulation of nitroso- degradation products from RDX was minimal. The biobarrier required no O&M other than injection/reinjection of oil substrate and had no impact on range activities. Additional information: ESTCP Cost and Performance ReportAdobe PDF Logo

Adobe PDF LogoRemediation of TNT and RDX in Groundwater Using Zero-Valent Iron Permeable Reactive Barriers: Cost and Performance Report
ESTCP, Project ER-0223, 66 pp, 2008

A mixed iron/sand PRB was installed to remove TNT and RDX contamination from groundwater at the Cornhusker Army Ammunition Plant near Grand Island, Nebraska. Performance was evaluated over a 20-month period. Installation costs for the pilot-scale barrier (50 ft long by 15 ft deep by 3 ft thick) were $138,000, ~$180 per square ft.

Adobe PDF LogoTreatment of RDX & HMX Plumes Using Mulch Biowalls
Newell, C. ESTCP Project ER-0426, 77 pp, 2008

The field demonstration conducted at the Pueblo Chemical Depot in Colorado represents the first ever application of mulch PRBs for the treatment of explosives contamination in groundwater. The state-mandated, site-specific cleanup criteria of 0.55 ppb RDX and 602 ppb HMX was used as the project goal. A pilot-scale organic mulch/pea gravel biowall 100 ft long and 2 ft thick was installed using one-pass trenching. The PRB was in place by November 16, 2005, and all performance objectives were met by June 2006, when the system appeared to have reached a pseudo steady state. See also the ESTCP Cost and Performance ReportAdobe PDF Logo

MTBE

Adobe PDF LogoIn Situ Bioremediation of MTBE in Groundwater
Johnson, P., C. Bruce, and K. Miller.
TR-2222-ENV, 118 pp, 2003

A biologically reactive ground-water flow-through barrier (a 'biobarrier') was established at the Naval Base Ventura County, Port Hueneme, CA, to prevent further contamination of ground water by MTBE leaching from gasoline-contaminated soils. The biobarrier was installed downgradient of a gasoline-spill source zone. Ground water containing dissolved MTBE flowed to and through the biobarrier, and the microorganisms in the treatment zone converted MTBE to carbon dioxide and water. Gas injection wells were installed to introduce oxygen into the treatment zone.

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