title: [Optimization of a modified UCT step feed process treating municipal wastewater].
abstract: A pilot-scale modified UCT step feed process was proposed to treat the municipal wastewater with lower COD/N in a large-scale wastewater treatment plant. Effects of influent distribution ratios and nutrients ratios (COD/N, COD/P and TN/P) on nutrients removal capabilities were importantly investigated. The removal mechanisms of organics and nutrients and sludge characteristics were ultimately discussed. According to the continuous experiments, the stable and high process performance was obtained. The average COD removal efficiencies and effluent concentration of (83.8 +/- 3.86)% and (43.7 +/- 8.35) mg/L were achieved in the influent COD loading of 0.79-0.93 kg/(m3 x d). The COD removal in anaerobic and anoxic zones accounted for 60.2% - 76.2%. With the influent distribution ratio of 40%: 30%: 30%, as much as 88.2% of TN removal efficiency was observed. It should be considered the removal of 32.8% through simultaneous nitrification and denitrification process. The average effluent NH(4+)-N and TN were (0.21 +/- 0.20) mg/L and (7.90 +/- 1.27) mg/L, respectively. It was extremely important that as much as 32.6% - 39.5% of the denitrifying phosphorus accumulation organisms contributed to the high phosphorus removal efficiency of 97.2%. A linear positive relationship was observed between nitrogen removal efficiency and COD/N in the range of 4.64 and 7.41 (R2 = 0.96). Phosphorus removal efficiency was found to be a function of the influent COD/P and TN/P, varying from 35.0 to 92.5 and from 6.24 to 12.5, respectively (R2 = 0.87 and R2 = 0.89). In addition, the great sludge settleability was obtained with the mean SVI of (82.6 +/- 4.99) mL/g.
authors.affiliation: Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China. gl-222@tom.com
authors.forename: Shi-Jian
authors.initials: SJ
authors.lastname: Ge
authors.forename: Yong-Zhen
authors.initials: YZ
authors.lastname: Peng
authors.forename: Xu
authors.initials: X
authors.lastname: Cao
authors.forename: Shu-Ying
authors.initials: SY
authors.lastname: Wang
authors.forename: An-Ming
authors.initials: AM
authors.lastname: Yang
mesh_terms: D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology; D002947:Cities; D009584:Nitrogen / Q000302:isolation & purification* / Q000378:metabolism; D010758:Phosphorus / Q000302:isolation & purification* / Q000378:metabolism; D010865:Pilot Projects; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D009584:Nitrogen