Ammonium removal in landfill leachate using SBR technology: dispersed versus attached biomass

Large concentrations and oscillations of ammonium nitrogen (NH 4 + -N) in municipal landfill leachate pose considerable constraints to its further treatment in central wastewater treatment plants. The aim of this study was to evaluate and optimize two technologies for the pre-treatment of 600 L/day of landfill leachate: in particular, to optimize their operational conditions for NH 4 + -N removal up to a level appropriate for discharge to sewers, i.e. 4 + -N from 666 mg/L (on average) at the inflow to below 10 mg/L at the outflow with alkalinity adjustment in a 12-hour cycle. Both technologies achieved 96% removal efficiencies for NH 4 + -N. However, SBR with dispersed biomass showed higher flexibility under varying conditions due to the shorter adaptation time of the biomass.