污水处理厂不同工艺的污泥脱水效能分析及其影响因素研究

污泥脱水是污泥减量的主要手段,直接影响到后续污泥处理处置.本研究以北京某大型污水处理厂A2/O工艺和A2/O-MBR工艺污泥脱水为对象,基于2013年全年的运行数据,分析不同工艺的污泥脱水效果、絮凝剂投配率、污泥脱水电耗和污泥脱水成本,并通过冗余分析(RDA)研究了不同污水处理工艺污泥脱水性能的影响因素.结果表明,污泥脱水性能和絮凝剂投配率均呈现季节性变化特征,冬季污泥较难脱水,絮凝剂消耗大.A2/O-MBR工艺的脱水污泥含水率年均值为(81.92±1.64)%,A2/O工艺为(82.56±1.35)%,污泥脱水絮凝剂消耗(以DS计,下同)分别为(8.70±7.25)kg·t-1和(7.42±2.96)kg·t-1,电耗(以DS计,下同)分别为331.82 k W·h·t-1和121.57 k W·h·t-1.A2/O-MBR工艺的污泥脱水絮凝剂成本(以DS计,下同)为204.76元·t-1,用电成本为231.61元·t-1;A2/O工艺的污泥脱水絮凝剂成本为175.00元·t-1,用电成本为84.86元·t-1.RDA分析表明,水温等季节性因素引起污泥有机质变化是影响污泥脱水性能的关键因素之一,此外,污泥龄也与污泥脱水性能有一定相关性.

Performance and Factors Analysis of Sludge Dewatering in Different Wastewater Treatment Processes

Sludge dewatering is one of the keys for sludge disposal and treatment of municipal wastewater treatment plants.In this study, the sludge dewaterability, flocculant consumption and costs of sludge dewatering for different wastewater treatment processes including A²/O and A²/O-MBR processes were analyzed, as well as the factors of sludge dewatering were analyzed by redundancy analysis (RDA) method, based on the data of one municipal wastewater treatment plant of Beijing in 2013.Results showed that both sludge dewaterability and flocculant consumption presented the seasonal variation, which means sludge dewatering was harder and coupled with higher flocculant consumption in the winter.Although the lower moisture content of dewatered sludge was obtained in the A²/O-MBR process (81.92%±1.64%) compared with that in the A²/O process (82.56%±1.35%), the consumptions of flocculant (8.70±7.25) kg·t^-1 DS] and electric energy (331.82 kW·h·t^-1 DS) in the A²/O-MBR process were higher than those in the A²/O process (7.42±2.96) kg·t^-1 DS, 121.57 kW·h·t^-1 DS for flocculant consumption and electric energy respectively], resulting in higher operation costs (RMB 204.76 yuan·t^-1 DS of flocculant consumption and RMB 231.61 yuan·t^-1 DS of energy consumption for the A²/O-MBR, RMB 175.00 yuan·t^-1 DS of flocculant consumption and RMB 84.86 yuan·t^-1 DS of energy consumption for the A²/O, respectively).Results of RDA showed that the seasonal variation of sludge dewaterability mainly depended on the content of organic matter in sludge which was related to the seasonal factors such as temperature, and was also impacted by the operating parameters such as SRT in wastewater treatment.