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<br /> ENHANCED REDUCTIVE DECHLORINATION RESULTS iN CONDITIONAL
<br /> CLOSURE AT TEXAS DRY CLEANER FACILI'T'Y
<br /> Rick Railsback(rrprogca@swbell.net)(ProGEA, Inc., Dallas,TX)
<br /> G.Shawn Hardy(Archon Group, Dallas,TX)
<br /> Rick Gillespie(Regeliesis,Lac., Plano,TX)
<br /> ABSTRACT: Cost effective remediation of chlorinated solvents in groundwater is a
<br /> significant challenge for retail dry cleaner facilities aavtss the United States. The toxicity
<br /> and distribution of the contaminants coupled with the proximity of nearby businesses and
<br /> residential areas limits the applicability of many conventional groundwater remediation
<br /> technologies. Thus paper presents results fro►n a full scale, in situ groundwater
<br /> remediation application at a Texas dry cleaner facility. Hydrogen Release Compound
<br /> (111110s)was injected into groundwater to serve as a slow release electron donor in order
<br /> to enhance the reductive dechlorination of the chlorinated solvents.
<br /> Primary groundwater contaminants at the site include tetrachloroethylene (PCE),
<br /> trichloroethylene (TCE), cis-l,2-dichloroethylene (cis-DCE), and vinyl chloride (VC).
<br /> Near the source arca, groundwater contaminant concentrations for PCE (4,500
<br /> microgratns/litcr,t►g/1), WE (1,000 ug/1), cis-DCE (7,300 ug/I), and VC (870 ug/1) were
<br /> recorded in MVd-3 immediately prior to 1IRC injection. The treatment area was
<br /> approximately 3,000 square feet (ft2) [283 square meters (m2)] - a portion of which
<br /> underlies the former dry cleaner's building foundation. in May of 2000, HRC was
<br /> injected into 45 borings within the contaminated arca. All 45 direct push borings were
<br /> installed to approximately 22 ft (6.7 m) below ground surface (bgs), and the ITRC was
<br /> injected evenly over the interval From approximately 7 to 22 It (2.1 to 6.7 In) bgs.
<br /> fiixtccii of the borings were instal led at angles of 15 and 30 degrees from vertical in order
<br /> to access contaminated groundwater beneath the building's foundation. A total of
<br /> approximately 7,000 pounds [3,171 kilograms (Kg)] of I IRC were injected at the site.
<br /> I11tC material costs were approximately 931,200, Direct push boring costs, concrete
<br /> coring and cutting, site cleanup, field supervision, consulting oversight and design, and
<br /> report writing costs were approxuuately $28,500. 'These one-time expenditures compare
<br /> very favorably to the initial and recurrent operating costs anticipated for other remedial
<br /> options. Approximately 18 months after 11RC injection, PCE, TCE, cis-DCF., and VC
<br /> levels had decreased to 408, 87, 438, and 132 ug/1, respectively. As of May 2001, all
<br /> contaminant levels at the site were below site target concenh•atioils established within the
<br /> Texas Voluntary Cleanup Program.
<br /> INTRODUCTION
<br /> A significant percentage of colnnlercial properties requiring environmental
<br /> cleanup have been contaminated by releases of the chlorinated solvent tetrachloroethylene
<br /> (PCE) by dry cleaning operations. Dry cleaning facilities have been ubiquitous in
<br /> commercial properties, particularly strip shopping centers, since the 1940s. A significant
<br /> percentage of these facilities have released PCE into the soil and groundwater beneath
<br /> Proceedings of Tho Bnttollo sponsored Thlyd International Conieranco an Remediation of Chlorinated and Recalcitrant Compounds.
<br /> Montmay,Caliromia,May 2023,2002.Published by 031telle Prese,ISBN 15747 7-132.9,20M.
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