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Remediation feasibility studies were conducted in simulated groundwater flow channels for carbon tetrachloride (CT). CT was introduced at a concentration of about 2 mg/L (∼13 μmoles/L) in three channels, two of them with alfalfa plants and the other with grass. Since no degradation products were found at the outlet after about 100 days, anaerobic conditions were created by adding one liter of 0.2% glucose solution in one channel (with alfalfa) and one liter of 0.1% emulsified soy oil methyl esters (SOME) to another channel (with alfalfa). The fraction removals of total chlorinated methanes in the outlet liquid were 94% in glucose fed channel and 92% in SOME fed channel. Supplements such as glucose, corn starch, cheese whey, and SOME stimulated the indigenous microbes to carry out the biodegradation of CT. In both glucose and SOME fed channels, the degradation continued several weeks after stopping the feeding of supplements. Most of the degradation process took place in the initial portion of the SOME fed channel, since SOME likely stayed near the inlet of the channel, due to sorption and retarded flow due to its low solubility; therefore, SOME should be added at multiple locations for effective bioremediation. No CT and degradation products were found in the headspace above the soil surface. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 444–453, 2014

A pilot field study was conducted for remediation of a tetrachloroethene (PCE)-contaminated site in Manhattan, Kansas. Prior to the pilot study, the PCE concentration in groundwater at the pilotstudy area was about 15 mg/L (91 μM). Nutrient solution comprising soy oil methyl esters (SOME), lactate, and yeast extract was added in the pilot-study area for biostimulation on August 18, 2005 (day 0). Potassium bromide (KBr) was added in the nutrient solution as a tracer. PCE was converted to dichloroethene (DCE) under these conditions. KB-1, a consortium of Dehalococcoides, and a second dose of nutrient solution were added on day 56. After addition of KB-1, both PCE and DCE concentrations decreased. Nutrients were again injected on day 197 (with KBr). On day 348, cheese whey was injected. Soluble nutrients and KB-1 migrated downstream, affecting PCE and DCE concentrations at downgradient wells; however, KB-1 moved slower than the aqueous phase.The total chlorinated ethenes (CEs) decreased by about 80 percent in the pilot-study area due to bioremediation. Biodegradation of CEs continued for several months after the addition of nutrients.A portion of the insoluble SOME was retained in the vicinity of the injection wells and provided a long-time source of nutrients and electron donors that supported degradation of PCE. A mixture of SOME and soluble substrates worked effectively in this study. O