A Study on Anaerobic Biodegradation of BTEX in Soil

BTEX anaerobic degradation processes is an international focus in the field of groundwater remediation, while systematic research is still unavailable in China. Centering on the screening of highly efficient BTEX degrading bacteria and controlling of the environmental conditions of in-situ repairing site, the study obtained three kinds of mixed flora and three pure strains by establishing the methods to extract, domesticate and screen mixed and pure species from BTEX contaminated soil. With nitrate, sulfate and ferric salt serving as electron acceptor respectively, the anaerobic degradation processes of single-component were studied to analyze and explore the efficiency of in-situ anaerobic degradation. The results showed that the anaerobic degradation order is as follows: toluene> benzene > xylene. Nitrate as an electron acceptor is more effective than sulfate and ferric salt. The three pure strains of bacteria were identified to be the yellow single spore bacteria, Lactobacillus micro-bacteria, and Bacillus-La. The effect order of the factors on anaerobic degradation was: electron acceptor>initial concentration>species. Concentration of electron acceptor was the most important influence factor for BTEX degradation efficiency. The degradation efficiency is also affected by initial concentration.