The results that the membrane bioreactor allows the treatment of ammonia and part of the COD, with a limited production of sludges. The elimination yields observed on the membrane bioreactor are high, starting from a biologicaly equilibrated efflent, since the ratio C/N/P is slightly deficient in P. The Chemical Oxygen Demand and Total Organic Carbon are climinated more than 70％. The Nitrification rate nears 98％ despite the important variability of the ammonia concentrations inside the raw leachate. The Suspended Solids are eliminated 100％ thanks to the microfiltration membrane.