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Electrokinetic-enhanced bioremediation of tetrachloroethylene

Chang, Chih-Hao, Yang, Hsin-Yi, Chen, Sheng-Kung, Hung, Jui-Min, Lu, Chih-Jen, Liu, Min-Hsin
International biodeterioration & biodegradation 2018 v.132 pp. 251-258
Dehalococcoides, aerobic conditions, bacteria, bioremediation, biotransformation, dechlorination, electrochemistry, electrolysis, ethidium, ethylene, hydrogen, methane, methanotrophs, mineralization, oxygen, tetrachloroethylene
This study investigated the feasibility of using electrolysis of water to produce hydrogen and oxygen that were used as the electron donor and the electron acceptor for the anaerobic reductive dechlorination and the aerobic cometabolism of chlorinated ethylene contaminants, respectively. By employing the anaerobic and aerobic conditions in different sections of a column test, intermediates formed in the anaerobic dechlorination of PCE in the up-gradient section were further biodegraded through aerobic cometabolism in the down-gradient section, which used methane as the primary substrate. The results indicated that, the effluent PCE concentration was 0.88 μmol l⁻¹ when the influent PCE concentration was 60 μmol l⁻¹, up to 98.5% PCE was degraded in 160 days with an additional current density up to 0.099 mA cm⁻². The First-order reaction rate was increased by 1.9–17.3 times with biostimulation by electrolysis method, showing that the benefits of an integrated electrochemistry and biotransformation system to complete mineralization of tetrachloroethylene. In addition, the specific microbial populations of Dehalococcoides sp. and methane-oxidizing bacteria were analyzed using the ethidium monoazide-PCR procedure, indicating the presence of viable bacteria in the integrated system.