title: Biological nutrient removal by applying modified four step-feed technology to treat weak wastewater.
abstract: For weak municipal wastewater (COD ≤ 200 mg L(-1), NH(4)(+)-N ≤ 40 mg L(-1)) with low influent C/N, a pilot modified four step-feed process was applied for simultaneous biological nitrogen (N) and phosphorus (P) removal under different inflow distribution ratios. It was designed with a short hydraulic retention time of 8.7h to raise influent load, and the optimal effluent performance of COD, NH(4)(+)-N, total nitrogen (TN) and total phosphorus (TP) were 33.05, 0.58, 9.26 and 0.46 mg L(-1), respectively with inflow distribution ratio of 20:35:35:10%. More than 74% of carbon sources were utilized effectively for phosphorus release and denitrification. About 16.7% of TN was removed through simultaneous nitrification and denitrification in oxic zones. Moreover, the commendable sludge settling with a sludge loading of 0.04-0.1 kg COD/kg MLSS d, attributed to the higher mixed liquor suspended solids (MLSS) and the alternating anoxic/oxic operational mode. In addition, the pre-anoxic zone designed was beneficial for both nitrate reduction and anaerobic phosphorus release.
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environmental Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China. caoguihua1983@emails.bjut.edu.cn
authors.forename: Guihua
authors.initials: G
authors.lastname: Cao
authors.forename: Shuying
authors.initials: S
authors.lastname: Wang
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Peng
authors.forename: Zhijia
authors.initials: Z
authors.lastname: Miao
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D009584:Nitrogen / Q000302:isolation & purification / Q000378:metabolism*; D010758:Phosphorus / Q000302:isolation & purification / Q000378:metabolism*; D010865:Pilot Projects; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D009584:Nitrogen; D010758:Phosphorus; D062065:Wastewater; D014874:Water Pollutants, Chemical