Abstract:The reuse of reclaimed water is an important way to solve the water crisis, but the secondary effluent of urban sewage plants still contains a large amount of pollutants, which pose a potential threat to people's health. In order to ensure the safety of reclaimed water reuse, exploring the method of biofilm slow filtration-sodium hypochlorite disinfection combined process for the treatment of secondary effluent of sewage plant was used to investigate the removal efficiency of organic matter and opportunistic pathogens in water. Analysis of influencing factors. The results show that under the same filtration rate, the biofilm slow filtration had better removal effect of dissolved organic compound than the slow filtration, and the removal effect of DOC was the best when the filtration rate was 20 cm/h; The treatment effect of product organic matter and humic acid organic matter was better than that of slow filtration; under the same filtration rate, the turbidity removal effect of biomembrane slow filtration was better than that of slow filtration; the optimum dosage of NaClO was 8.0 mg/L ( Under the condition of effective chlorine concentration), the combined process of biofilm slow filtration-NaClO disinfection has better removal effect on Legionella and Pseudomonas aeruginosa, and NaClO has better removal effect on pathogenic bacteria in free suspension state. Excellent; In addition, lower pH value and higher water temperature are more conducive to the removal of conditioned pathogens in water by NaClO disinfection. It is concluded that the biofilm slow filtration-sodium hypochlorite disinfection process can effectively control pollutants such as organic matter and opportunistic pathogens in the secondary effluent, and can ensure the safety of reclaimed water reuse to a certain extent.