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Very little information is available regarding the 1989 pilot test of injected microbes and <br /> nutrients; therefore, no detailed analysis can be presented. <br /> Nestle implemented three different phases of soil vapor extraction (SVE) work to <br /> remediate soil and soil vapor impacts to the vadose zone. Details of SVE efforts are <br /> presented in Attachment A.3. <br /> A description of the potassium permanganate, carbohydrate, and SVE remedial methods <br /> and results of the pilot tests or implementation are summarized below. <br /> 3 W-SITU TREATMENT USING POTASSIUM PERMANGANATE <br /> Potassium permanganate is soluble in groundwater and is an effective oxidizer of <br /> trichloroethylene (TCE) by breaking its double carbon bonds to produce environmentally <br /> benign reaction products including chloride and carbon dioxide. Its effectiveness is <br /> limited in less permeable formations or when the subsurface aquifers are interbedded <br /> with low permeability clays and silts. <br /> In August 1999, the IT Corporation (IT) injected potassium permanganate in four <br /> locations at three depth intervals in the Upper Aquifer. Pumping from three extraction <br /> wells in various configurations was introduced to enhance hydraulic mixing. IT collected <br /> pilot test data from ten monitoring wells over a six-month period. <br /> Although TCE oxidation was observed in all seven monitoring wells and cis-1,2-DCE <br /> oxidation occurred in six of the wells monitored; concentration rebound occurred in most <br /> wells within 28 weeks. Evidence of permanganate was limited to a 20-foot zone <br /> surrounding the injection points. Elevated TDS was observed in some of the wells in the <br /> pilot study area and persisted until groundwater extraction and treatment was restarted. <br /> In-situ treatment using potassium permanganate is not feasible for treating COCs in <br /> groundwater at the Site because: <br /> • multiple deliveries of a very large mass and high volume of potassium <br /> permanganate at closely placed injection points would be required to maintain <br /> appropriate subsurface conditions to destroy TCE, and <br /> • the high volume of permanganate would increase already elevated levels of TDS. <br /> Attachment A.1 includes a detailed description and assessment of the previous <br /> potassium permanganate injection tests performed at the Site. <br /> 4 OCTOBER 2005 W-SITU TREATMENT USING CARBOHYDRATE <br /> (MOLASSES) INJECTION <br /> The addition of a carbohydrate solution to groundwater containing chlorinated volatile <br /> organic compounds (VOCs) stimulates native microbial populations and promotes the <br /> reduction of chlorinated VOCs by dehalo-respiration. Carbohydrate is both an energy <br /> source and a carbon source that may increase the growth and viability of a variety of <br /> different groups of subsurface microorganisms that reduce solid and dissolved mineral <br /> constituents and other relatively oxidized species, such as TCE. Dehalo-respi ration is <br /> dependent upon appropriate site-specific conditions, such as groundwater flow rate, <br /> mineralogy, and nutrient availability, described in Attachment A.2. <br /> 3 <br />