天然地下水环境四氯乙烯的强化生物降解

Enhanced Biodegradation Potential of Tetrachloroethylene under Natural Groundwater Environment

采用批实验方法,以天然地下水为基础培养液,利用在实验室条件下培养驯化的微生物,以醋酸作为共代谢基质,加入酵母粉提供氮源,研究了四氯乙烯(PCE)的降解效果.研究表明,通过强化影响PCE降解的某些因素,在20℃的地下水环境中,PCE可以很快转化为三氯乙烯(TCE),并可以进一步转化为二氯乙烯(DCEs),但没有检测到DCEs的脱氯产物.PCE的脱氯速率为0.1848d-1,半衰期为3.75d.亦研究了低温环境下PCE的降解效果.结果表明,在低温环境下,PCE也可以发生生物降解,但是脱氯速率相对较慢,为0.0761d-1,半衰期为9.11d,且终产物为TCE.

In order to investigate tetrachoroethylene （PCE） biodegradation potential by some enhanced factors, the experiment was carried out under natural groundwater condition by batch experiment. Microorganism cultured in the laboratory was added to the microcosm with acetic acid as electron donor and yeast powder as nitrogen source. Experimental results indicate that PCE could be dechlorinated to trichloroethylene （TCE） and dichloroethylene （DCEs） under 20 ℃. TCE was the primary dehalogenation product, and small amounts of dichloroethylenes （DCEs） were also detected. No significant further DCEs degradation was detected. The degradation rate of PCE was 0. 184 8 d^-1 , and the half life was 3. 75 d. Under 12 ℃ condition, PCE biodegradation could occur; however, the terminal product was only TEE without DCEs, and degradation rate of PCE was 0. 076 1 d^1 , which was relatively slow compared to that under 20 ℃ .