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

本研究的目的是建立厌氧与好氧相结合的四氯乙烯（PCE）完全降解工艺。首先研究了有机酸作为电子给体对土壤环境中PCE脱氯的影响。有机酸促进了PCE的降解，并作为这些有机酸的代谢产物生成氢。研究了土壤环境中氢浓度对PCE降解的影响。高氢浓度抑制PCE的完全脱氯，低氢浓度有利于PCE的完全脱氯，控制氢对PCE的脱氯非常重要。在厌氧条件下，顺式二氯乙烯（cis-DCE）在土壤环境中积累。甲烷氧化细菌Methylocystis sp.菌株M对DCE具有较高的降解活性。Methylocystis sp.， M菌株测定了二氯乙酸为DCE的代谢物。厌氧系统和好氧系统的组合系统可以有效地完成PCE的降解。

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.