城市污水处理厂承载着水污染控制的重要任务。为了保护生态环境，污水厂执行的排放标准越来越严格，污水处理成本也越来越高。本研究旨在掌握典型二级处理工艺的运行特性，包括进出水水质、污水处理效果的季节性变化、进水有机物和悬浮物负荷对处理效果的影响、进水营养物质比例对处理效果的影响，以及这些工艺能耗、药耗的差异，为污水二级处理工艺的选择提供理论指导，为降低污水处理厂运行成本提供建议。对AAO工艺运行特性的研究发现，考察的26个污水厂的进水指标浓度均呈正偏态分布（均值>中位数>众数）。出水各指标2017及2018年一级A标准达标率在91.2%（SS）-98.4%（NH3-N）之间。华东地区污水厂进水各指标受季节的影响较为显著，进水污染物浓度呈现夏季低、冬季高的趋势。进水有机物负荷集中在0.1-1.5 kgCOD/(m3?d)，进水SS负荷集中在0.05-1.0 kgSS/(m3?d)。污水可生化性较好，能满足生物除磷以及生物生长对氮磷的需求，但反硝化碳源不足。对循环式活性污泥法（CAST）工艺运行特性研究发现，考察的7个污水厂的进水指标浓度均呈正偏态分布（均值>中位数>众数）。出水各指标2017及2018年一级A标准达标率在50.9%（SS）-99.8%（BOD5）之间。华东地区污水厂进水各指标受季节的影响较为显著，进水污染物浓度呈现夏季低、冬季高的趋势。进水有机物负荷集中在0.1-1.0 kgCOD/(m3?d)，进水SS负荷集中在0.01-0.2 kgSS/(m3?d)。污水可生化性较好，能满足生物生长对氮磷的需求，但反硝化、生物除磷碳源不足。对曝气生物滤池（BAF）工艺运行特性的研究发现，考察的4个污水厂的进水指标浓度均呈正偏态分布（均值>中位数>众数）。出水指标2017及2018年一级A标准达标率在82.0%（TN）-100%（COD）之间。东北地区污水厂进水各指标受季节的影响较为显著，进水污染物浓度呈现夏季低、冬季高的趋势。进水有机物负荷集中在0.3-2.5 kgCOD/(m3?d)，进水SS负荷集中在0.4-2.0 kgSS/(m3?d)。污水可生化性较好，能满足生物除磷以及生物生长对氮磷的需求，但反硝化碳源不足。综合对比上述三种处理工艺，就本研究中考察的污水厂而言，AAO工艺平均占地面积、吨水药耗和电耗均高于CAST和BAF工艺。CAST工艺平均占地面积及吨水电耗高于BAF工艺，但BAF工艺的吨水药耗则高于CAST工艺。工业废水处理所需的占地面积、吨水药耗和电耗、单位污泥产率均高于生活污水。
Wastewater treatment plant carries essential mission of water pollution control. In order to protect the ecological environment, the effluent discharge standard of wastewater treatment plants is becoming stricter, and thus the operating costs are also growing. The purpose of this study is to obtain the operational characteristics of typical secondary treatment processes, including influent and effluent quality, seasonal variation of treatment performance, impact of influent organic matter load and suspended solid load on treatment effect, influence of influent nutrient proportion on treatment effect, and energy and chemical consumption of these processes. This study aims to provide theoretical guidance for selection of secondary treatment processes and provide advice on reduction of the operating costs. According to the study on the operational characteristics of anaerobic-anoxic-oxic (AAO) process, the influent concentration of 26 wastewater treatment plants in this study showed a trend of positively skew distribution (mean > median > mode). The probability of effluent concentration reached the Class-A standard was in the range from 91.2%(SS) to 98.4%(NH3-N). The concentrations of BOD5, COD and TP in the influent of wastewater treatment plants in east China, and the concentrations of BOD5, SS, NH3-N and TP in the influent of wastewater treatment plants in northeast China were low in summer and high in winter. The organic matter load in the influents was in the range of 0.1-1.5 kgCOD/(m3?d), and the suspended solid load in the influents was in the range of 0.05-1.0 kgSS/(m3?d). The results indicated that the influents had good biodegradability, could meet the demand for biological phosphorus removal and could meet the demands of nitrogen and phosphorus for microbial growth, but could not offer adequate carbon source for denitrification.The study on the operational characteristics of the cyclic activated sludge technology (CAST) process reflected that the influent concentration of the 7 wastewater treatment plants in this study was in accordance with positively skewed distribution (mean > median > mode). The probability of effluent concentration achieved the Class-A standard was in the range from 50.9%(SS) to 99.8%( BOD5). The concentrations of BOD5, COD, SS, NH3-N, TN and TP in the influent of wastewater treatment plants in east China, and the concentrations of TP in the influent of wastewater treatment plants in northeast China were low in summer and high in winter. The organic matter load in the influents was in the range of 0.1-1.0 kgCOD/(m3?d), and the suspended solid load in the influents was in the range of 0.01-0.2 kgSS/(m3?d). The results revealed that the influents had good biodegradability, could meet the demands of nitrogen and phosphorus for microbial growth, but could not provide sufficient carbon source for denitrification and biological phosphorus removal.The study on the operational characteristics of biological aerated filter (BAF) process demonstrated that the influent concentration of the 4 wastewater treatment plants in this study was conformed to positively skewed distribution (mean > median > mode). The probability of effluent concentration got to the Class-A standard was in the range from 82.0%(TN) to 100%(COD). The concentrations of BOD5, COD, SS and TP in the influent of wastewater treatment plants in northeast China were low in summer and high in winter. The organic matter load in the influents was in the range of 0.3-2.5 kgCOD/(m3?d), and the suspended solid load in the influents was in the range of 0.4-2.0 kgSS/(m3?d). The results displayed that the influents had good biodegradability, could meet the demand for biological phosphorus removal and could meet the demands of nitrogen and phosphorus for microbial growth, but could not supply plenty of carbon source for denitrification.Among the three treatment processes, AAO process needs higher average area occupation, chemical and energy consumption of per ton water than CAST and BAF process, according to the data analyzed in this study. CAST process needs higher average area occupation and energy consumption of per ton water than BAF process, but BAF process needs higher chemical consumption of per ton water than CAST process. Industrial wastewater treatment has higher demand of area occupation, chemical and energy consumption of per ton water, and higher per unit sludge yield than domestic wastewater treatment.
