title: Granulation of activated sludge in a pilot-scale sequencing batch reactor for the treatment of low-strength municipal wastewater.
abstract: Aerobic granulation of activated sludge was achieved in a pilot-scale sequencing batch reactor (SBR) for the treatment of low-strength municipal wastewater (<200 mg L(-1) of COD, chemical oxygen demand). The volume exchange ratio and settling time of an SBR were found to be two key factors in the granulation of activated sludge grown on the low-strength municipal wastewater. After operation of 300 days, the mixed liquor suspended solids (MLSS) concentration in the SBR reached 9.5 g L(-1) and consisted of approximate 85% granular sludge. The average total COD removal efficiency kept at 90% and NH4+-N was almost completely depleted (approximately 95%) after the formation of aerobic granules. The granules (with a diameter over 0.212 mm) had a diameter ranging from 0.2 to 0.8 mm and had good settling ability with a settling velocity of 18-40 m h(-1). Three bacterial morphologies of rod, coccus and filament coexisted in the granules. Mathematical modeling was performed to get insight into this pilot-scale granule-based reactor. The modified IWA activated sludge model No 3 (ASM3) was able to adequately describe the pilot-scale SBR dynamics during its cyclic operation.
authors.affiliation: Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Bing-Jie
authors.initials: BJ
authors.lastname: Ni
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Xie
authors.forename: Shao-Gen
authors.initials: SG
authors.lastname: Liu
authors.forename: Han-Qing
authors.initials: HQ
authors.lastname: Yu
authors.forename: Ying-Zhe
authors.initials: YZ
authors.lastname: Wang
authors.forename: Gan
authors.initials: G
authors.lastname: Wang
authors.forename: Xian-Liang
authors.initials: XL
authors.lastname: Dai
mesh_terms: D000332:Aerobiosis; D000641:Ammonia / Q000032:analysis; D019149:Bioreactors; D002947:Cities; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D009573:Nitrites / Q000032:analysis; D010100:Oxygen / Q000302:isolation & purification; D010865:Pilot Projects; D012722:Sewage; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: D009573:Nitrites; D012722:Sewage; D000641:Ammonia; D010100:Oxygen