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砂土中柴油迁移土柱实验与反硝化条件下苯生物降解微环境实验研究

The Study of Diesel Oil Migration in Sand Soil by Column Experiments and Benzene Biodegradation under Denitrifying Condition by Laboratory Microcosms

【作者】 李东艳

【导师】 钟佐燊; 汤鸣皋; 罗人明;

【作者基本信息】 中国地质大学(北京) , 水文学及水资源, 2000, 博士

【摘要】 本文以柴油为非混溶污染物的代表,通过土柱实验评价均一砂土介质中柴油在完全干燥、残余含水和水位波动条件下的残余饱和度;并在此基础上进行了淋滤实验,评价淋滤作用对残余饱和度的影响。研究表明介质的粒径和和含水量对柴油的残余饱和度有着较大影响。水的渗透流速小时,对残余油的重分布影响不大,以缓慢的溶解作用为主。生物恢复技术是一种极具应用前景的地下水有机污染治理技术。反硝化条件下苯的生物降解目前仍是一个有争议的问题。为探讨反硝化条件下苯的生物降解,以未污染的稻田土为接种物,进行了一系列的微环境实验研究。结果表明反硝化条件下苯和甲苯都能被微生物降解。甲苯比苯更易降解,甲苯的存在促进了苯的降解。本研究中反硝化条件下苯生物降解的一个显著特点是滞后期短,降解速率快,电子受体的消耗量小。在此基础上,提出了今后研究的方向。

【Abstract】 When groundwater was contaminated by organic chemicals, the residual saturationof organic chemicals in vadose zone and saturated zone is an important parameter toestimate the range of contamination and choose remediation technology. To evaluate theresidual saturation of diesel oil in uniform sand material under dry, residual watersaturation and water table fluctuation conditions, soil column experiments were carriedout. Then water infiltration tests were performed to estimate the influence on theredistribution of residual diesel oil. The results indicate that grain size and initial watercontent have an important impact on the oil residual. When the infiltration of water is low,it has a small influence on the residual saturation. The main process is solution. Thisstudy indicates that the residual contaminants in vadose zone are long-term pollutionsources, and that can’t be ignored in groundwater remediation.Bioremediation is a promising technology to remedy and control ground waterorganic pollution. Significant portion of petroleum contaminated aquifers are anaerobicas the result of microbial respiration consuming the low concentrations of oxygen andbecause rates of reoxygen are relatively slow. There are many studies on anaerobicbiodegradation in the past two decades. Up to now, it is still a controversial question thatwhether benzene could be biodegraded under denitrifying condition. This studyinvestigated the biodegradation of benzene in laboratory anaerobic microcosms. Theinocula were from uncontaminated rice soil. The results indicated that benzene andtoluene degradation occurred concomitantly with nitrate reduction in enrichment andtransfer cultures. Toluene was degraded more readily than benzene, and benzenedegradation was enhanced by the presence of toluene. Benzene was biodegraded rapidlyafter a short lag time. Author thinks the species of microbial may be the key factor ofbenzene biodegradation. When benzene doesn’t sever as the growth substrate ofindigenous microbial, inoculation might be a feasible means.

  • 【分类号】TU441.4
  • 【被引频次】6
  • 【下载频次】480
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