The Study Of Diesel Oil Migration In Sand Soil By Column Experiments And Benzene Biodegradation Under Denitrifying Condition By Laboratory Microcosms

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.