结合东北某石油污染场地的水文地质特征,通过影响因素试验探讨了不同环境因子对微生物生长及降解地下水中苯和二甲苯效果的影响作用。同时,通过土柱实验,分析了微生物在不同砂土介质中的迁移规律和降解地下水中苯和二甲苯的效果。结果表明,微生物降解苯和二甲苯的最佳条件为,培养基温度20℃、pH值7.0、添加氮磷和溶解氧(DO)5.21mg/L。微生物在砾砂、粗砂和中砂中的迁移速度随着介质平均粒径和孔隙度的增大而加快。在同一种介质中,微生物穿透前20cm所需时间大于穿透后20cm所需时间,在不同介质间,微生物穿透40cm所需时间均为:砾砂<粗砂<中砂。总的来说,随着介质平均粒径的变小,苯和二甲苯的去除率增加。在中砂介质中,苯和二甲苯的去除率达到40%以上。

Based on the hydrogeological characteristics of field site contaminated by the petroleum in the Northeast of China, the effects of environmental factors on the growth of microorganisms and the biodegradation of benzene and xylene are investigated by batch experiment. Also, the migration rules for microorganisms in different sandy media and the biodegradation of benzene and xylene using biosparging are carried out by column experiment. The results indicate that the optimal condition for the biodegradation of benzene and xylene is as follows: the temperature is 20℃, pH value is 7.0, nitrogen and phosphorus added and DO is 5.21mg/L. The migration velocity of microorganisms increases with the diameter and porosity of the media increasing. For one kind of medium, the time for microorganism penetrating first medium of 20cm is longer than last medium of 20cm. For different media, the time taken by microorganisms to penetrate the medium of 40cm is in an ascendant order, namely, gravelly sand<coarse sand<medium sand. Generally speaking, with the diameter of the media decreasing, the removal rate of benzene and xylene increases and in the medium of medium sandy, the removal rate reaches at above 40% by biosparging.