电动-微生物修复胶质污染土壤微生物活性分析

Microbial activity analysis during the electrokinetic-bioremediation of resin-contaminated soil

胶质在自然环境中难以降解,长期累积,是石油污染土壤修复中急需解决的难点。胶质结构中含有大量芳香环、杂环和羧基等难降解的官能团,其降解率并不足以说明对污染土壤的修复效果。土壤微生物群落是土壤中重要的活体成分,通过MicroRespTM方法可测定其活性,并作为评价污染修复效果的重要指标。本文从辽河油田原油中提取胶质配制污染土,并加入构建的混合菌群,设计微生物修复(Bio)、电动-微生物修复(EK+Bio1)、电动-微生物补充营养修复(EK+Bio2)以及间断电动-微生物修复(EK+Bio3)共4种处理。修复后,胶质平均降解率EK+Bio2>EK+Bio3>EK+Bio1>Bio,降解率最高为9.82%,为Bio处理的3.06倍(3.21%)。修复后土壤微生物数量增加,其趋势与胶质降解率保持一致。MicroRespTM法实验结果表明,修复后土壤中微生物代谢能力增强、活性提高。不同处理下微生物对碳源有不同的选择性,修复后微生物对糖类的代谢能力得到较大提升。电动-微生物联合修复可提高胶质降解率,并使土壤中微生物数量增加,代谢能力提升,活性增强。

Resin,due to its extreme difficulty to be degraded in nature,plays an essential role during the remediation of petroleum-contaminated soil. Resin has high environmental risks since it could accumulate long time in the environment. Functional groups in resin structure such as aromatic nucleus and carboxyl groups are hard to be degraded. Consequently,degradation rate is not enough to indicate the effect of remediation. MicroResp^TM method can be used to assess soil community level physiological profiles,which is an important index reflecting the effect of remediation. In this study,resin obtained from Liaohe oilfield and superior mixed bacteria were prepared for the remediation. There were four treatments,including bioremediation( Bio),electrokineticbioremediation( EK+Bio1),electrokinetic-bioremediation with nutrient matters( EK+Bio2) and discontinuous electrokinetic-bioremediation( EK+Bio3). The results showed that the average degradation rate varied among different treatments,with an order of EK+Bio2>EK+Bio3>EK+Bio1>Bio. The highest degradation rate was 9.82%( for EK+Bio2),which was 3.06 times of that Bio( 3.21%). The abundance of microorganisms increased after remediation,the trend of which was similar to the degradation rate of resin. The results of MicroResp^TM analysis showed that the microbial metabolism and microbial activity were promoted. Microorganisms had selectivity of carbon sources under different remediation approaches. The ability of microorganisms to metabolize saccharides substantially increased. In conclusion,electrokinetic-bioremediation could promote the degradation of resin as well as enhance the physiological profiles of soil community.