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 eliminated 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.