A laboratory-scale treatment process was set up to treat Port Mann Landfill leachate, a high ammonia, low degradable carbon leachate with occasional high metals. A single sludge, nitrification/denitrification system was run for 25 weeks, with methanol added as a carbon source to improve denitrification. The objective of the treatment process was to remove biodegradable carbon and ammonia (feed levels of 25 to 250 mg/L).
Carbon removal, including methanol, was adequate at SRT's of 10 days or greater. An SRT of 5 days produced inadequate treatment. Of the metals of concern, all except nickel were concentrated in the biomass. Ammonia removal was inconsistent. Good nitrification occurred at the start of the study but no denitrification occurred until operating conditions were optimized. Both processes deteriorated as the study progressed. The study clearly demonstrated that changing influent characteristics constrained the overall treatment of the leachate.