"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... . '; -'.-
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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
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