"United .States -''. '', .;-.: / : environmental Protection v- Agency. ' "''" :. EFW54Q/MR-00/5Q4, December2000' :" SUPERFUND IMNQMT1VE TECHNOLOGY B/ALUA TIQN Demonstration Bulletin ln-Siu Bioremefliaiion Process Project Description: The U.S. Environmental Protection. Agency (EPA) conducted an evaluation .of .the Enhanced In- Situ Bioremediation. Process., a biostimu.lation technp'lpgy . developed; by. the U.S.Department of Energy (DOE)' at "the Westinghogse Savannah RiyenPlant sitejn.Aiketi,SC. DQE, has licensed the process to Earth Tech,-'Inc. (Earth Tech)., The eyaluati'bn despribed in, this bulletin was carried. out by ' the EPA'Superfund Innovative Technology Evaluation (SITE) Program* Earth Tech is utilizing the process.to deliver a rnix-.' ,ture of air aiid,gaseous phase nutrients,, and/or methane tp : cpntarriiriated grouiidwater in fractured bedr.ock';at a site in Rpanpke, VA^hese enhancements are delivered to cohtami-. nated grpundwater via an injection well and were: designed tp'stimuiate and. accelerate the growth of existing microbial pppulations, especially 'rhethanptrophs. This type, of aerobic bacterium has. the. ability to metabolize methane and;p.ro- duce enzymies c'apableof degrading chlorinated solvents.and their degradation-products tP npnfhazardous constituents. . : The primary components of'Earth Tech's treatment system consist of an injection well, air injection-equipment, ground-. water monitoring wells; and soil vapor monitoring points. The injection, well is designed to deliver air; nutrients, and.meth- surface. For the system evaluated, the air was supplied by a 'compressor that was capablepf delivering 15-30 psi and ap- prpximately SOscfm to the injection well, the rtic-nitoring wells and soil y^por triohitprihg. point?, were installed upgradient, down-gradient and cross-gradient relative to the injection well location to 'delineate the.zone of ihflue.rtce .and to monitor groundwater.within and putside of thezprie of influence.The . soil vapor monitoring points'can be;designed to release or capture'vapors that may build up in the. overburden. The . monitoring wells were constructed in a manner to allow therh, to be converted toeither irijeptipn wells or soil vapor extrap- tion.points. .": '; ,!'. \''''..'';",:- ':'"''':"',. ''"''".-:.; '.'.... The-typical injection' system Consists of air, ^nutrient, and methane injection e'quipmeht; all can be housed ina tempo- rary building or shed; A'cornpressor Serves as the air source^ and includes a condensate tank ("trap") With a drain, an air line, ..coa.lescing filters arid pressure regulators, apd; valves. The' methane and nitrous oxide provide thS source of carbon and nitrogen, respectively. Both are provided in standard gas : cylinders and are piped into the main air line using regula-. ; tors''and;:flow meters. Triethyl.phosphate .(TEP), thp phosr phofous source,.is.iri liquidstate..and isstored-in.a.pressure': rated steel tank: Arr from the rna n line is'diverted through the tanktoi'vo'ialillzQ-theTEP'for^subsurfacedeliyery.Thea,ir,,ril- .. trous oxide, ,and TE.P are injected cbritin.upusly While the . methane;is injected Jb'n'a pulsed schedule, the^metharie js closely mpnitored just prior to injecting intp-supsurface wells: : to ensure th'at the injecition concentration'dpes not.exceed, 4°/o by volume,: thus avoiding the methane lower' explosive . limit (LEL) of 5%.; :.;,. ": . ';/..;''';.-;';''.': ".-. ..'' v "' u -' Waste Applicability: The' Enhanced In-Situ Bioremediation . process-is applicable fortreating volatile organic compounds .' (VObs): in groundwater that ca.n be naturally biodegfa'ded, .-'. including some hard to degrade phlprinated ,VOCs.. the mix- -'. ture of air.and 'gaseous phase nutrients that is injected into the Subsurface provides-an aerobic environment for. cbntami- " "n'ant degfadatipn. Toxic .products 'resulting from, anaerobic..' degradation of chlorinated solvents (e.g:, yinyl chloride) may. .be broken down completely,-iri.this aerobiP enyironment. The in-situppcessls especially applicabiefor.hydrogeologica'lly complex sites where injected nutrient flpw paths-are uripep: tairt;(i..e.; in fractured bedrock gaseous phase nutrient injec- . ; tionjis more likely to affect a-larger area, than; liquid .nutrient , injection).,the process is also applicable in situations' where ^subsurface, utilities limit or'preclude the use of technolpgie's : requiring excavation. .;-, v ', .. ,-, :' :. .bemonstratiQn Results: .A pilot-scale .technology demonr..:. stration bf.the Enhanced In-Situ Bioremediation process-was ..-conducted from March 1998 to July 1999 at the ITT Indus-' ' tries Night Vfsio'h (ITFNy) .piyision'plaht in Roanoke, VA. The, \ JTTNV facility is an actiyie. rnanufacturing plant that produces night visiort devices and. related night visio'n products for both' - goyerrirnerit and cornrnercial customers: C3rpund.water con-, tarhination at the facility has resulted from tankJeaks ofboth',.'' chlbrinated and 'ripn-chlprinated compounds, which were . used-as manufacturing cleaning solvents; Remediation, is .being cohducted at the.facility as a RCRA,Interim Measure . (\Mj:, and .is cprnplicated by'target .VOCs occurring in frac- tured bedroclc below -the sUrface.This logistical complexity presented by the area geology was a key factor for selectirig thei Enhanced'In-Situ.Bioremediatipnprocess.....-'' ". '.-'; the,demonstration study area was located:adjacent to . . ITTMV's commercial operations building (Building 3), and was immediately dowrigradient of a cpntamination source.that had - . .resulted from a leak of an underground waste splvent tank. The study area.is the only location at the facility where the.' source release has Ppntaminated the grbuhdwater with both: chlorinated and non-ch'lorinated groups of VQ.Cs, Several VOQ ' ' '' : '" 80%Recycleci/Recyclable Printed with vegetable-based ink on . paper that contains a minimum of., 60% post-consumer fiber oontept.-. : processed chlorine tree... . '; -'.- ------- United States , , Environmental Protection Agency .National Risk Management Research Laboratory; Cincinnati; OH 45268. -" Official Business , ' Penalty for Private Use $300 ,. ,- ' EPA/540/MR-00/504 PRESORTED STANDARD POSTAGE & FEES PAID -EPA PERMIT NO. G-35 compounds'have been detected in.th.e-groundtoater at this location above their respective Federal, Maximum Contami- nant Level (MCL)iThese compounds include actual spjverits, such as 1ri.chloroethe.ne (TCE). arid 1,t,1-tfichlprpethane ; (TGA), as welt as' several of their breakdown products, prior to the start of trie demonstration methane was present and TCE was absent from some-ofthe wells. These'Observations. strongly suggest that anaerobic'degradation'..of'TCE was - . naturally occurring. ' .'_" :"''"; \ ;'V.-, The Earth Tech system installed at the, study area cbnsisted of eleven monitoring poihts.These included;an injection well, ' four monitoring wells.loca.ted within, the radius of influence,.-' two monitoring wells located outside of the radius of -influ-. t ence (i.e., ohe upgradtent and one downgradient), and four. soil vapor monitoring points. Selection of the spe'cific .con- taminants and wells to evaluate was based on review of his- torical site data, results from a pre-demonstrati.on sampling event, and on a statisticai'analysis. Emphasis.was placed 911- sampling the four monitoring'wells Jocated within the.radius of'influence, which were designated as "critical, welfe" F-our . specific contaminants_were associated- with these wells that exhibitedacceptable temporal and spatial variability for eyalu-; ating the technology. These "critical analytes""included.: chloroethane '(CA); 1,1-Dichlor6etharie (1,1-DCA)', cis-1,2- Dichloroethene (cis-1,2-DCE), andVinyl Chloride'(VC).TCE was not selected because it did not exhibit acceptable tem- poral and spatial variability/.'. ; ; ' .:" . ' '',' The primary objective of the demonstration was to evaluate Earth Tech's claim that there'would be a minimurh 6f .75%:. reduction (with a 6.1 level of significance) in the grpundwater , concentration of each of the four critical'ahalytes within the zone of influence, following six months; of treatment. How-: 'ever,- process optimization and'"modif ications resulted, in -ex- tending the evaluation period-to sixteen months. Based on the above-mentioned claim artd'pre-dernonstratiph data,- ah experimental design was developed to'guide the evaluation,. During the baseline and final sampling events, .one g.round- , water sample from each of .the four critical wells was coj- .lected for VOC analysis-daily for.seven consecutive-days '(fpr 'a total pf.28 samples per event). . ,..""-,'' ' - ,.':': Results from the Earth Tech In^-Situ Biorerriediatibn-.Technol'- ogy demonstration are presented in Table 1 and are based on the 28 baseline and 28 final sarnples for the four critical anajytes. YOG concentrations were.determined by EPA SW- 846'jyi'etho'd 8260.the results indicate t.hdt the targeted.75%, ^reduction-was achieved or exceeded for two of thefour critj-. , cal compounds,,fromi baseline .to final events^ . : :. :,' Tsble 1 i Groundwaiter.Results. Target . V ' .'' Compound CA . .'-.'' .1,1-DCA ' .. cfe-1,2-DCE ,.vo -V ; i'. Contaminant . ;' Concentration . . ... .' Baseline- Final' v :'A 330- .': '' 960 3,100 :. 210'- ;. -' 19'b . 90 -' '. Average. ' ' Percerit '.' '. Reductipn "' ' SO "V; :.-./..^l97,^; - Statistically . '. . Significant" . >--i '."; ^'Percent'.' ' ' Reduction' -'.' - -"- ,' ^'-.'-. ',4 ''..":"' '.';, '.>" '- . '" ,95 ':-':- '..'' -:,; ..gf:- ;.,;.- .. . ; Values are the average of 28. results from four wejls, and roundecJ totwo'isignlficant.digits. :-:."..' ,.,'.^1.' '';."'' -'..,..,: Percent reductions shown represent the Lower Cpnfi'dence-iirrtit (LCL) for the Average Percent Reductfons, wi^h a pit ley^l of 'significance., .':,' '':... " :. ' ' . , : ;, ',, An, InnovativeTechnoJogy'Evaluatipn Report (ITER) describ- ing'- the complete: demonstration will be available in'th'e riear. future.-Forfurther information please contact the following: , : EPA Project Manager ;. '.''-. ] '';,-:, ':.;.' . Vince Gallardo '. '..'- ' , , ' :.; , ;:u,s.EPA"'';.-.. ;. : /'.:. :';: ;:-': ,'-\;- !::' ;- ;: ,;-.',^ :''. .Natioriai.Risk Management.Research Laboratory (NRMRL). 26 West Martin'Luther King.Jr; Drive ' -:', ,, 'Cincinnati, OH 45268 /":;' ..'"',: ;' '','''''''-'..':'".'. . .;E-rnail:,galIa'rdp'.vincente@ epa.gov ------- |