Treatment of high ammonia concentration landfill leachate with an anaerobic filter and rotating biological contractor (RBC)

Landfill leachate discharge potentially results in degradation of the receiving environment. One of the primary leachate contaminants of concern is nitrogen, which in the form of ammonia is toxic to aquatic life, and in the form of nitrate may cause eutrophication of the receiving water body. For these reasons, it is often desirable to totally remove nitrogen from leachate prior to discharge to the environment. Biological nitrogen removal appears to be the most practical method of removing nitrogen from leachate. Rotating biological contactors (RBC’s), in particular, have been shown to effectively nitrify high ammonia leachate. If sufficient carbon is available, anaerobic biological treatment processes have been shown to effectively denitrify aerobically treated leachate. This thesis investigates the use of a predenitrifying anaerobic filter and a rotating biological contactor to remove nitrogen from a high ammonia concentration leachate from a municipal solid waste landfill in Kaohsiung, Republic of China. The primary objective of the research was to determine the effects of high ammonia concentration on RBC ammonia loading and removal. Secondary objectives include removing organics and metals from the leachate. The research indicated that 97% ammonia removal from high ammonia leachate (mean 2,140 mg/L) can be achieved at RBC loading rates up to 1.5 g/m 2/day. At higher loading rates, ammonia removal was inhibited. Nitrogen removal for the system averaged 66%, including an estimated 54% in the RBC. Nitrogen removal in the RBC was either the result of simultaneous nitrification/denitrification or air stripping of ammonia in combination with nitrification. Both alkalinity consumption and COD removal results support the explanation that simultaneous nitrification/denitrification (potentially aerobic denitrification) occurred, but since RBC off—gasses were not monitored, neither theory can be confirmed. BOD and COD removal in the system averaged 92% and 49%, respectively. COD:BOD removal was 3.7:1. The system did not effectively remove metals. Overall removal of dissolved metals ranged from —19% for nickel to 59% for manganese. Organic complexing of the metals most probably resulted in low removals.Applied Science, Faculty ofCivil Engineering, Department ofGraduat