Optimisation of n removal in landfill leachates treatment with membrane bioreactor : pilot plant an full scale studies.

Biological treatment of landfill leachates was followed during a year in a membrane bioreactor (MBR) facility located in east Luxembourg. Good removal performances were observed but at high aerated volumes ratio. A pilot scale MBR was put into operation, treating the same leachates to demonstrate that similar performances could be reached with lower aeration volumes (lower cost). Results show that a removal of 99.4% of ammonia could be maintained with an aeration volume decrease from more than 75% to near 5% of the total volume. TN removal was also enhanced with no external carbon addition. Simulations with activated sludge model nº1 were performed with good predictions when aeration was high. When aeration was lowered, ASM1 predictions failed, so an adapted model for the particular case of nitrogen removal was tested. The adapted model that includes two-step nitrification and anammox activity shows better results, demonstrating the potential of these processes in landfill leachates biological treatment.