Method for treating sewage by virtue of high-interception membrane bioreactor

The invention discloses a method for treating sewage by virtue of a high-interception membrane bioreactor. The bioreactor is a closed pressure-tolerant integrated submerged device adopting a nanofiltration membrane, the nanofiltration membrane is adopted as a separation core so that the problem that a microporous filtration membrane or ultrafiltration membrane in the conventional membrane bioreactor cannot effectively intercept small molecular organic pollutants in water can be solved and the quality of the effluent is greatly improved; and compressed air is adopted as a power source, the pressure of the compressed air is controlled to fluctuate within the range of 0.1-0.7MPa by virtue of an exhaust valve so that membrane surface adhesive layer which is coated on each partition plate cannot stably exist and the membrane surface contamination is delayed. The pressurized gas is adopted as aeration and power, the solubility of oxygen in water can be increased so as to facilitate the generation of microorganisms and maintain higher concentration of sludge and degradation rate than those of the ordinary MBR, the problems of too low water permeability due to adopting the suction technique when the nanofiltration membrane is adopted in the integrated MBR are effectively solved, and the damage of high-speed shearing of a pump to the microorganisms having a degradation effect and easy pollution of the nanofiltration membrane when a split-type MBR is adopted are effectively solved.