Biological nitrogen removal from landfill leachate: a pilot-scale study

A pilot-scale two-stage process including an anaerobic pretreatment (up-flow anaerobic sludge blanket, UASB) unit and a pre-denitrification activated sludge process was studied for treating leachates from a municipal landfill (waste aged 4 to 5 years, area 2.5 ha) and from a windrow composting area (1ha). A single-stage pilot process was used for nitrification studies. The leachate characteristics were as follows: COD 740 to 2400 mg 1-1 (chemical oxygen demand), BOD7 (biochemical oxygen demand) approximately 1000 mg 1 -1, Ntot 40 to 120 mg 1-1 and the temperature was between 2 and 21°C. The results show that 45 to 50% COD removal could be achieved in the UASB reactor even at temperatures b…