[Degradation mechanism and efficiency of organic pollutants of landfill leachate in different redox zones].

A soil column filled with sandy soil was constructed to investigate degradation mechanism and efficiency of organic landfill leachate pollutants in subsurface environment. Experimental results indicated that iron reduction zone may be play an important role on degradation of organics, and its efficiency was up to 86.24% averagely, reduction zone for nitrate, sulfate and methanogenic followed, and that was 75.93%, 79.81%, 74.02% and 65.09% averaged, respectively. Anaerobic reducing environment could have played an important role on degradation of benzoxazole, antipyrine, indene, etc. naphthalene, cyclohexanone and part of cyclo-alkyl hydrocarbon, etc. Which were difficult to biodegrade. Maximum degradation efficiency of pollutants was different in different redox zones. For instance, in sulfate reduction zone, the highest degradation efficiency of 1, 1, 1-trichloroethane and 1, 2-dimethylbenzene was 80% and 71.43%, respectively. The highest degradation efficiencies of TCE and MTBE were in nitrate reduction zone, and reached 81.25% and 92.58%. respectively; Benzene was degraded completely in sulfate reduction zone and iron reduction zone.