title: [Effects of influent C/N ratio on performance of UniFed SBR process].
abstract: The effects of 7 groups of different influent C/N ratio (2.75, 4.28, 5.7, 6.5, 6.97, 8.08, 11.19) on the removal efficiencies of total nitrogen, phosphorus and COD as well as the sludge settling performance were investigated in a UniFed SBR lab-scale apparatus treating actual domestic wastewater. The results showed that when the C/N ratio was lower than 5.7, TN removal efficiency increased sharply as C/N ratio increased, from 43.6% of 2.75 to 80.84% of 5.7. Afterwards, TN removal efficiency increased very slowly as C/N ratio increased, because only TN removal efficiency caused by SND during aeration period could be enhanced. P removal efficiency increased as C/N ratio increased, because PAOs could get more organic carbon source from the influent to produce PHB and release PO4(3-), avoiding the adverse influence of NO(x)- on PO4(3-) release. The higher the C/N ratio, the more the quantities of P release and uptake, the quicker P uptake rate, the better P removal performance was. Regardless of the C/N ratio, excellent COD (average 93.15%) removal efficiencies were maintained throughout the experiment. When Influent C/N ratio was bigger than 6.97 and organic load exceeded 0.38 kg/(kg x d), SVI rose quickly as C/N ratio increased. Non-silk bacteria sludge bulge appeared because of low DO and high organic load.
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environmental Recovery Engineering, Beijing University of Technology, Beijing 100022, China.
authors.forename: Chen-Hong
authors.initials: CH
authors.lastname: Zhao
authors.forename: Yong-Zhen
authors.initials: YZ
authors.lastname: Peng
authors.forename: Shu-Ying
authors.initials: SY
authors.lastname: Wang
authors.forename: Xu-Guang
authors.initials: XG
authors.lastname: Tang
mesh_terms: D019149:Bioreactors / Q000382:microbiology; D002244:Carbon / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D010758:Phosphorus / Q000302:isolation & purification / Q000378:metabolism*; D015203:Reproducibility of Results; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen