Citation:
Proceedings Sardinia 2003. 9th International Waste Management and Landfill
Symposium. S. Margherita di Pula, Cagliari, Italy; 6-10 October 2003
Abstract:
Ammonia can be removed from landfill leachate through aerobic biological
processes. The biological aerated filter (BAF) combines biological treatment and
subsequent biomass separation in one reactor providing a small footprint
alternative to conventional systems. Leachate from an operational landfill was
found to be aerobically treatable using the OECD recommended Modified Zahn-
Wellens test. This leachate was used as feed to a pilot-scale BAF at influent
COD and ammoniacal-nitrogen concentrations of 765 mg/l and 568 mg/
l respectively. During an initial period of stable operation without pH control,
33 % of influent ammonia was removed. The reactor pH was 9.2 with little
conversion to total oxidized nitrogen (<45 mg/l). Therefore this removal was
accounted for primarily by air stripping. In a second period of stable
operation, the reactor pH was reduced to pH 7.2 by addition of hydrochloric
acid. Ammonia removal was increased to 97 % with a concomitant increase in
effluent nitrite concentration to an average of 524 mg/l. Biological aerated
filters can therefore be used to nitrify landfill leachates.
