Hoss' 4-stage biological nutrient removal (BNR) activated sludge process for removal of total phosphate and total nitrogen to a level below 1.0 mg/l without any chemical coagulation process such as alum or ferric chloride used for phosphorous removal

摘要

A biological nutrient removal (BNR) system to treat a typical U.S. municipal/domestic wastewater. This BNR system consists of four main directly interflowing of anaerobic, aerobic, anoxic and re-aeration. In the municipal/domestic wastewater treatment industry, the past multi-stage suspended waste activated sludge treatment facilities have been adding coagulant chemicals such as alum to remove total phosphorous (TP) and total nitrogen (TN) to 1.0 mg/l and 3.0 mg/l, respectively. This BNR system is a unique activated sludge biological configuration capable of treating wastewater biologically for clarifier effluent TP and clarifier effluent TN to a level less than 1.0 mg/l for each pollutant without any coagulant chemical additions.