Development of complete degradation of tetrachloroethylene by hybrid methods of anaerobic and aerobic processes

本研究旨在建立厌氧-好氧联合降解四氯乙烯（PCE）的完全降解工艺，首先研究了土壤环境中有机酸作为电子供体对PCE脱氯的影响。有机酸促进PCE的降解，并从这些有机酸的代谢产物产生氢。研究了土壤环境中氢气浓度对PCE降解的影响。结果表明，高浓度的氢气抑制了PCE的完全脱氯，低浓度的氢气有利于PCE的完全脱氯。氢的控制是PCE脱氯的关键。在厌氧条件下，顺式二氯乙烯（cis-DCE）在土壤环境中积累。甲烷氧化菌Methylocystis sp.菌株M对DCE具有较高的降解活性。二氯乙酸被确定为代谢产物二氯乙酸的Metylocystis sp，菌株M。提出了甲基孢囊菌M菌株好氧降解DCE的途径。厌氧-好氧联合系统对PCE的完全降解是有效的。

The purpose of this research is to establish complete degradation of teterachloroethylene(PCE) by combining anaerobic and aerobic degradation process.At first, effect of organic acids as electron donors on PCE dechlorination was studied in soil environment. Organic acids enhanced the PCE degradation and hydrogen was generated as metabolic products from these organic acids. Effect of hydrogen concentration on PCE degradation was investigated in soil environment. It is suggested high hydrogen concentration inhibited the complete dechlorination of PCE.The low hydrogen concentration is favorable to complete dechlorination od PCE. To control hydrogen is very important for PCE dechlorination. At anaerobic condition, cis-dichloroethylene(cis-DCE) was accumulated in soil environment. Methane oxidizing bacterium Methylocystis sp. strain M shows high degradation activity foe DCE. Dichloroacetic acid was determined as a metabolite of DCE by Metylocystis sp, strain M. Aerobic DCE degradation pathways by Methylocystis sp. strain M were proposed. It seems that combined systems of anaerobic and aerobic systems is was effective to complete degradation of PCE.