innovative technology evaluation program, camp edwards, massachusetts: part 1—soil treatability...

Federal Facilities Environmental Journal/Summer 2002 95

David L. Hill, Benjamin P. Gregson, Katherine R. Weeks, and Scott C. Veenstra

© 2002 Wiley Periodicals, Inc. * This article is a U.S. Government work and, as such, is in the public domain in the United States of America.Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/ffej.10037

Innovative TechnologyEvaluation Program,Camp Edwards,Massachusetts: Part 1—Soil Treatability Studies

David L. Hill, Benjamin P. Gregson, Katherine R. Weeks,and Scott C. Veenstra

Live-fire training activity dating from around 1941 to 1997 resulted in the depositionof spent munitions, propellants, and explosives in impact-area soils at the CampEdwards Training Ranges on the Massachusetts Military Reservation. Resultingcontaminants of concern, including RDX, HMX, TNT, and 2,4-DNT, are found inparticulate form and are heterogeneously dispersed in the soil. An InnovativeTechnology Evaluation (ITE) Program was initiated by the Army National Guard inMarch 2000 to investigate the potential for remediation of these soils.

Remediation technologies chosen for the ITE program to address thisproblem included soil washing, low-temperature thermal destruction (LTTD),composting, solid-phase bioremediation, bioslurry, chemical oxidation, andchemical reduction. The soil washing process was shown in field trials to reducethe volume of soil requiring further treatment by 75 percent. All technologieswere effective on soils that had been treated using soil washing. LTTD, solid-phase bioremediation, and bioslurry were effective on untreated soil, whilecomposting was less effective, and chemical reduction and oxidation were nottested on untreated soils. © 2002 Wiley Periodicals, Inc.*

INTRODUCTIONTarget practice and other range training operations have historically

occurred at Camp Edwards. Such activities were conducted sporadicallyin the 1930s, but increased substantially starting in 1941. In 1997 the U.S.

David L. Hill has overseen the Innovative Technology Evaluation (ITE) program since November2000 for the Impact Area Groundwater Study Program (IAGWSP) at Camp Edwards. Prior to this,he served for five years as the Army National Guard program manager’s representative for workconducted under the auspices of the Installation Restoration Program at Massachusetts MilitaryReservation. Benjamin P. Gregson, a licensed site professional in Massachusetts, has been theprogram manager of investigations and remediation for the IAGWSP at Camp Edwards since spring2001, and has been with this program since February 1999. Katherine R. Weeks is an environmentalengineer managing the ITE laboratory studies and field demonstrations of both soil and groundwatertreatability studies. She has worked on the program since April 2000. Scott C. Veenstra hasprovided senior management for the ITE program since its inception in March 2000. He alsomanages response actions and berm maintenance programs elsewhere at Camp Edwards.

96 Federal Facilities Environmental Journal/Summer 2002

Innovative Technology Evaluation Program, Camp Edwards, Massachusetts: Part 1—Soil Treatability Studies

Environmental Protection Agency (USEPA) issued an administrativeorder to cease live-fire training based on detections of explosives such ashexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in the drinking water aquifer un-derlying the base.

The live-fire training resulted in wide dispersion of low concentra-tions of spent munitions, propellants, explosives, and heavy metals inparticulate form at Camp Edwards. Residual explosives then migratedto the groundwater, approximately 100 feet below ground surface. Tosupport protection of the groundwater, the National Guard Bureau(NGB) instituted the Innovative Technology Evaluation (ITE) programto study technologies that might meet the requirements for remediatingsoil and groundwater at the site. Successful innovative soil remediationtechnologies were defined as those technologies that can meet USEPArequirements to address remediation of the identified areas of concern.

In developing recommendations for ITE studies, the NGB assembled anITE review team, including NGB, the Army Corps of Engineers (ACE), theArmy Environmental Center (AEC), and AMEC Earth and EnvironmentalInc. (AMEC) as the supervising contractor. The team assessed remediationtechnologies for participation in the treatability studies. Soil cleanup goalsestablished for the treatability studies included RDX (120 µg/kg), HMX (250µg/kg), TNT (250 µg/kg), lead (300 µg/kg), and dieldrin (246 µg/kg).

The technologies chosen for the ITE program were chemical oxida-tion, chemical reduction, thermal desorption/destruction (low-tem-perature thermal destruction [LTTD]), bioslurry, composting, andsolid-phase bioremediation.

SOIL WASHING PRETREATMENTThe team incorporated experience with a soil washing technology

already demonstrated on the site as part of a Rapid Response Action. Insoil washing, the fraction of the soil containing the contaminants ofconcern can be isolated and segregated from the remaining clean soil.

This physical process involves the following steps: physical sizing,density separation, classification/attrition, magnetic separation, and wa-ter treatment/dewatering. Physical sizing isolates soil fractions contain-ing heavy metals for subsequent density treatment from “clean” soilfractions. Magnetic separation recovers ordnance fragments and otherferrous material. Density separation recovers particulate metal. Classifica-tion/attrition partitions the residual organic or sorbed contaminants fromthe larger soil grains into the organic matter and/or fine soil fraction forsubsequent remediation using physical, chemical, or biological processes.Fines and humic material can be removed during the dewatering part oftreatment or by using a hydrocyclone as a form of density separation.

Because soil washing may be implemented at Camp Edwards, it wasdetermined that washed soil would be used in the ITE studies. Therefore,the studies were performed both on washed soil and on untreated soilcollected directly from the site.

The live-fire trainingresulted in widedispersion of lowconcentrations of spentmunitions, propellants,explosives, and heavymetals in particulate format Camp Edwards.



LABORATORY TREATABILITY STUDIESIn preparing for chemical oxidation and reduction studies, it was

determined that these processes would be performed on washed soilsonly, as part of an overall treatment design to include soil washing as thefirst treatment step. One chemical reduction study was designed tosimulate the reductive treatment of soil as a separate follow-on treatmentafter the soil washing process. This was done by adding 5 percentzerovalent iron (ZVI) (mass:mass) in the form of iron filings, acetic acid,and aluminum sulfate solution to washed soils in a mixture of 60 percentsolids and 40 percent liquid for five days. A second study was designedto simulate reductive treatment within the soil washing process, in aslurry of approximately 7 percent solids. The slurry was agitated for fourhours, dewatered, and incubated for five days.

Chemical oxidation was studied by adding 1 percent to 4 percent hydro-gen peroxide with ferrous sulfate as a catalyst (Fenton’s Reagent) to a 7 percentsolids slurry to simulate oxidization of contaminants during the soil washingprocess. The slurry was agitated for four hours and then air-dried.

A proprietary LTTD process was tested on both washed and un-washed soil. LTTD involves slowly heating soil to between 200º and300ºC, and holding for a minimum of 24 hours at the elevated tempera-ture. These temperatures were chosen to bracket the temperatures atthermal processes that would degrade or vaporize explosives com-pounds; for example, HMX melts at 285ºC and TNT boils at 240ºC.

The bioslurry process was tested on washed and unwashed soils.Molasses was added at a ratio of 0.3 percent (mass:mass) to a slurry of 30percent soil and 70 percent water. Two studies were performed duringthe study period of 35 days, one where slurry was constantly stirred ata low speed, and one where the slurry was intermittently stirred.Intermittent stirring may facilitate anaerobic conditions, which arepreferred for RDX and HMX degradation.

Composting was also tested on both the washed and unwashed soils.Each of the 12 reactors contained approximately 30 percent soil and 70percent organic matter, including various forms of locally availablemanure, cranberry mash, and wood chips, and was maintained attreatment temperatures for 12 to 45 days.

Solid-phase bioremediation studies were performed on both washedand unwashed soil. Two separate forms of the proprietary DARAMEND®

treatment were tested. In addition, powdered iron was added to the soilto control the redox potential. An initial 2 percent application ofDARAMEND® was added to the soil, as well as 0.2 percent powderediron. Weekly amendments of 0.5 percent DARAMEND® and 0.2 percentpowdered iron were then added to the soil during the 50-day test period.

RESULTS AND CONCLUSIONS OF LABORATORY-SCALESTUDIES

Several findings were observed during the course of the studies. First, theheterogeneous distribution of the explosives residues of RDX and HMX atthis site resulted in soil concentrations ranging up to five orders of magni-

LTTD involves slowlyheating soil to between200º and 300ºC, andholding for a minimum of24 hours at the elevatedtemperature.



tude difference within duplicate samples. This heterogeneous distributionaffected conclusions drawn after review of the analytical results.

Second, the explosive contaminants RDX and HMX do not adsorbonto the sandy soil grains at Camp Edwards. After soil washing, asignificant proportion of explosive contaminants was co-located withthe process water and organic matter. Therefore, the initial soils avail-able for the study contained lower concentrations of explosives thanexpected. However, this finding may further support the use of soilwashing as a treatment process, in that the vast majority of the explosivecontaminants may be removed from the mineral soil particles andisolated into the organic matter and process water.

Third, in previous studies, 95–99 percent of fresh RDX has been shownto be extracted using 18-hour sonication in acetonitrile, but only 85–90percent of weathered RDX was extracted using the same technique. Thismay have implications for the time required for dissolution of weatheredRDX into water, which affects analytical results. However, it has evenbroader impact on the design of soil sampling procedures for sites contain-ing weathered explosives, and on remediation processes that will be effec-tive on these soils, as will become apparent in the results of these studies.

Washed soils. In general, all studies on washed soils showed reduc-tions of RDX and HMX, there being no detectable or low concentrationsin the initial samples. Exhibits 1 and 2 show results for the chemicaloxidation and reduction studies, both of which were performed usingthe washed soil. Chemical oxidation did not reduce explosives concen-trations below soil cleanup goals. Therefore no further study of thisprocess was made. Chemical reduction was shown to be effective inreducing the RDX concentrations to below soil cleanup goals. Results

Exhibit 1. Chemical Oxidation Results, Washed Soils—Brice/UNL



Exhibit 2. Chemical Reduction Results Washed Soils—Brice/UNL

Exhibit 3. Low Temperature Thermal Destruction, Untreated(Unwashed) Soils—Terra Therm



suggest that the iron plus aluminum sulfate treatment in a post-soilwashing treatment regime was the most effective and yielded resultsbelow soil cleanup goals for explosive compounds.

Untreated soils. The studies on unwashed soils showed varying suc-cess in reducing RDX concentrations. Exhibits 3, 4, 5, and 6 displayresults for LTTD, bioslurry, solid-phase bioremediation, and composting.The following summarizes the results:

• LTTD was effective in degrading explosive compounds in soilbelow soil cleanup goals when temperatures of 250ºC or morewere applied, as expected. The lower temperature of 200ºC wasineffective in destroying HMX.

• Bioslurry was effective in degrading explosive compounds toconcentrations below the soil cleanup in the intermittently stirredreactors, but not in the constantly stirred reactors.

• Composting was effective in achieving soil cleanup goals forHMX but not RDX.

• Solid-phase bioremediation was effective in degrading explosivecompounds below soil cleanup goals in one of two similarunwashed soil tests.

As noted previously, the heterogeneous and particulate nature ofexplosives in soils had implications on data evaluation and comparisonof laboratory studies. The average concentration can be greatly influ-enced by the existence of particulates, especially in smaller data sets, and

Exhibit 4. Bioslurry Results, Intermittent Stirring, Unwashed(Untreated) Soils—Envirogen



Exhibit 5. Composting Results, Untreated (Unwashed) Soils—BSI

Exhibit 6. Solid-Phase Bioremediation Results, Untreated (Unwashed) Soils—GraceCanada



is not necessarily representative of overall contamination of the soil. Forexample, if the average concentration alone is used as a measure ofsuccess, composting and solid-phase bioremediation do not successfullydegrade RDX. Therefore, the median concentration is also provided inthe exhibits to give a balanced view of the effectiveness of the technologyin treating explosives-contaminated soil. The median concentration is anindicator of the overall success of the technology. However, the technol-ogy must be able to treat explosives in all forms, including the particulateform, and therefore it is important to see the impact of the particulates onthe outcomes of the studies. For this reason, both average and mediandegradation curves are shown.

Subcontractors were requested to focus on reduction and/or destruc-tion of explosives contaminants. Other contaminants were described butnot emphasized, including metals and pesticides. Chemical reductionand LTTD were found to be reasonably likely to achieve the RRA (RapidResponse Action) soil cleanup goals for dieldrin. LTTD was also foundto achieve these goals for the remaining organic contaminants of con-cern. Metals were not treated by any technology tested.

RECOMMENDATIONS FOR FIELD DEMONSTRATIONSEvaluation of the laboratory treatability studies for soil remediation

was completed in October 2001. Recommendations for field-scale dem-onstrations were made for chemical reduction as secondary treatmentafter soil washing, biodegradation using either bioslurry or solid-phasebioremediation as a secondary treatment after soil washing, and LTTDas either a stand-alone process or secondary after soil washing. Imple-mentation of LTTD will also require review by the Department ofDefense’s Explosives Safety Board.

The National Guard Bureau is currently in the process of developingdesigns and cost estimates for field demonstrations of these technologies, aswell as evaluating the work required to support the field demonstration. ❖

ACKNOWLEDGMENTSThe authors would like to thank Lieutenant Colonel Joe Knott of the

National Guard Bureau, Ms. Heather Sullivan and Mr. Ian Osgerby ofthe Army Corps of Engineers, Mr. Wayne Sisk and Mr. Mark Hamptonof the Army Environmental Center for their support and advice as partof the Innovative Technology Evaluation Team for the soil treatabilitystudies at MMR, and Ms. Deborah Taege, Mr. Eric Johnson, Ms. MariaPologruto, and Ms. Kathleen Sellers of AMEC for their assistance in theproject.

REFERENCESAMEC Earth and Environmental Inc. (2001, August). Revised final innovative technologyevaluation—Soil treatability study summary, Camp Edwards, Massachusetts MilitaryReservation. Prepared for the National Guard Bureau. Westford, MA: Author.

AMEC Earth and Environmental Inc. (2001, August). Innovative technology evaluationsupplemental soil treatability study summary—Bioslurry, Camp Edwards, MassachusettsMilitary Reservation. Prepared for the National Guard Bureau. Westford, MA: Author.



Gorontzy, T., Drzyzga, O., Kahl, M.W., Bruns-Nagel, C., Breitung, J., von Löw, E., &Blotevogel, K.-H. (1994). Microbial degradation of explosives and related compounds.Critical Reviews in Microbiology, 20(4), 265–284.

Jenkins, T.F., Grant, C.L., Brar, G.S., Thorne, P.G., Ranney, T.A., & Schumacher, P.W.(1996, September). Assessment of sampling error associated with collection and analysisof soil samples at explosives-contaminated sites (USACRREL, Special Report 96-15).Hanover, NH: U.S. Army Cold Regions Research and Engineering Laboratory.

Jenkins, T.F., Walsh, M.E., Thorne, P.G., Thiboutot, S., Ampleman, G., Ranney, T.A., &Grant, C.L. (1997, September). Assessment of sampling error associated with collectionand analysis of soil samples at a firing range contaminated with HMX (USACRREL/NTIS ADA330661). Hanover, NH: U.S. Army Cold Regions Research and EngineeringLaboratory.

Ogden Environmental and Energy Services (now AMEC Earth and Environmental).(2000, July). Final rapid response action work plan and draft release abatement measureplan, Camp Edwards Massachusetts Military Reservation. Westford, MA: Author.

Warminsky, M., Knott, J., Weeks, K., & Jones, C. (2001). Innovative application ofenvironmental technology simplifies rapid response action soil cleanup at MMR.Proceedings of the 27th Environmental & Energy Symposium & Exhibition. NationalDefense Industrial Association.

innovative technology evaluation program, camp edwards, massachusetts: part 1—soil treatability...

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