Method for synchronously degrading carbon, nitrogen and phosphorus in wastewater without discharging sludge

The invention provides a method for synchronously degrading carbon, nitrogen and phosphorus in wastewater without discharging sludge. The method is characterized in that the organic sludge is not discharged so as to increase the organic loading (supplementary carbon source) of a reactor, meanwhile, the parameters of a membrane bioreactor are controlled so as to form the facultative (or oxygen deficiency) state, the synchronous treatment of wastewater and sludge and the nitrogen and phosphorus removal are realized in the facultative membrane bioreactor (FMBR), and the treatment link is simplified; the organic sludge is used as the internal supplementary carbon source of the FMBR, so that resources are saved, and the carbon emission is reduced; the organic sludge is not discharged, so that the secondary pollution risk is avoided.