Stability and efficiency of biofilms for landfill leachate treatment.

The objective of this work was to assess the feasibility of a fixed-film biological aerated filtration process for the treatment of the leachate produced at Harnhill landfill site (South Gloucestershire, UK). The laboratory scale plant consisted of four identical biological aerated filters (a triplicate and a "control" column) packed with small brick fragments. Biofilm formed within 24h of immersion of the support material in the reactor, and had a high resistance to antibiotics and other toxic agents. The plant maintained a stable operation in the 20-45 degrees C temperature range, showing the best results (35.4+/-6.6% COD removal and 73.9+/-5.5% BOD(5) reduction) at 40 degrees C. The lowest COD and BOD(5) values obtained at the outlet of the columns were 7067 mg/L and 1050 mg/L, respectively.