The device adopts the principle of sequence-membrane to treat the pollutant. Sewage first enters into the buffer tank to adopt the biochemical treatment. Meantime the tank can contain the sewage peak load. When the liquid in the tank reaches the starting-level, the sewage is transferred into the sequence tank with soft stuffing, and treated with the way of sequence biological contacted oxidization treatment. Then the treated sewage is transferred into the clean water tank. When the liquid reaches the certain level, the clean water is transferred into the membrane assembly or discharged directly. The permeated effluent should be discharged to overboard after ozone disinfection or UV disinfection. The quality of the effluent meets with the requirements of IMO MEPC159( 55) resolution. For this product, we have gained CCS type approval certificate, IMO certificate, USCG,ABS and EC certificate.