High ammonia landfill leachate treatment using anaerobic filter and rotating biological contactor

Abstract

A pre-denitrifying anaerobic filter and a rotating biological contactor (RBC) were used to remove nitrogen from a high ammonia landfill leachate collected from a municipal and industrial solid waste landfill in Kaohsiung, Taiwan, Republic of China. The research indicated that greater than 95% ammonia removal from high ammonia-N (2140 mg/L) leachate can be achieved with RBC ammonia-N loading rates up to 1.5 g/(m2∙d). At RBC loading rates of 1.5–3.0 g/(m2∙d), ammonia removal ranged from 80% to 90%. Nitrogen removal averaged 66%, including an estimated 54% removal in the RBC. Nitrogen removal in the RBC was the result of either simultaneous nitrification and denitrification or air stripping of ammonia in combination with nitrification. Both alkalinity consumption and COD removal results support the explanation of simultaneous nitrification and denitrification (potentially aerobic denitrification); but since RBC off-gasses were not monitored, neither theory can be confirmed. The high nitrogen removal in the RBC suggests that for this leachate the anaerobic filter was not required for ammonia and nitrogen removal. BOD and COD removal averaged 92% and 49% respectively. Key words: landfill, leachate, treatment, ammonia, rotating biological contactor (RBC), nitrification, denitrification.