Described herein are methods and systems for combination membrane/biolytic filtration. In one embodiment a filtration system is operated under suction. The arrangement includes a feed tan (5) having a smaller filtrate vessel (6) positioned therein. The region within, the feed tank (5) not occupied by the filtrate vessel (6) is partially filled with layers of decomposing and decomposed solid organic waste material to form an aerobic filter bed (7) of the type used in biolytic filtration as described above. A further module vessel (8) is mounted within the filtrate vessel (6) to form a membrane chamber (9) containing a membrane filtration module (10).