The polluted (waste) water discharged from the pollution source, due to the high total amount or concentration of pollutants, does not meet the requirements of discharge standards or does not meet the requirements of environmental capacity, thereby reducing the water environmental quality and functional goals, it must be artificially enhanced. In the sewage treatment process, the indicators that need to be monitored include ammonia nitrogen, total phosphorus, total nitrogen, COD, pH, dissolved oxygen, and biochemical oxygen demand.