NOVELTY - Wastewater treatment system comprises: an anaerobic reactor used for removing methane and carbon dioxide formed by decomposition of organic matter in effluent free of suspended solids using anaerobes; a fluidized bed membrane reactor used for anaerobically removing particulate contaminants in effluent during the process of recovering methane from residual organic matter in effluent discharged from anaerobic reactor simultaneously; and a biological nitrogen removal reaction tank used for removing residual ammoniacal nitrogen in effluent, or a physicochemical nitrogen removal reaction tank.    USE - Used as a wastewater treatment system.    ADVANTAGE - The system has simple structure, improves the water quality of the effluent by removing the particulate contaminants in the effluent, remarkably reduces the sludge production quantity and lightens the subsequent sludge treatment, ensures reduced power consumption, and utilizes the coherence precipitation reaction tank to remove phosphorus in the effluent.    DETAILED DESCRIPTION - Wastewater treatment system comprises: an anaerobic reactor used for removing methane and carbon dioxide formed by decomposition of organic matter in effluent free of suspended solids using anaerobes; a fluidized bed membrane reactor used for anaerobically removing particulate contaminants in the effluent using a membrane during the process of recovering methane from the residual organic matter in the effluent discharged from the anaerobic reactor simultaneously; and a biological nitrogen removal reaction tank used for removing residual ammoniacal nitrogen in the effluent discharged from the membrane reactor under low dissolved oxygen concentration using Anammox (RTM: Process for removing nitrogen from wastewater) reaction, or a physicochemical nitrogen removal reaction tank used for removing ammoniacal nitrogen remaining in the effluent discharged from the anaerobic fluidized bed membrane reactor by physicochemical process including ammonia degassing or struvite precipitation method.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the anaerobic fluidized bed reactor, the anaerobic fluidized bed membrane reactor and the biological nitrogen removal reaction tank of the wastewater treatment system (Drawing includes non-English language text).    Fluidized particles (42)    First gas-fluidized particles separation unit (43)    Circulation unit (44)    Feed pump (45)    Efflux pump (56)