The concentration of organic pollutants in domestic sewage is low, sewage BOD5/CODcr ≥ 0.45, biochemistry is better, so the treatment process can be biochemical treatment based on the selection of A/ O process, biochemical tanks need to be divided into two parts of the A-level pool and O-level pool. Sewage lifting pump to the anaerobic pool, the use of anaerobic bacteria, so that organic hydrolysis, acidification, removal of organic matter in wastewater, and improve the biochemistry of wastewater, anaerobic pool effluent into the aerobic pool, oxidation of the pool for aeration of the blower, nitrification, absorption of phosphorus, the removal of BOD (or COD), etc., the second sedimentation tank for the separation of sludge and water, the effluent by the disinfection device disinfection and then meet the standards for discharge. Sewage to meet the standard