AAO+MBR工艺在高标准污水厂节地设计中的应用

Utilization of AAO+MBR Process for Land Saving Design of a Wastewater Treatment Plant with High Discharge Standard

茂名市某污水处理厂进水以城镇生活污水为主,设计规模为4.5×10^(4)m^(3)/d,出水水质执行《地表水环境质量标准》(GB 3838—2002)的准Ⅳ类标准(TN除外),BOD_(5)、SS及NH_(4)^(+)-N设计去除率均高达95%左右,用地指标为0.35 m^(2)/(m^(3)·d^(-1)),仅为相关规范建议值的1/3。为了满足出水水质要求和用地限制,主体工艺采用AAO+MBR,相比混凝沉淀深度处理工艺节地效果明显;生化池设计污泥负荷为0.065 kgBOD_(5)/(kgMLSS·d),好氧池设计污泥浓度为9 000 mg/L,设计气水比为4.9:1;采用三级污泥回流,设计回流比分别为300%、200%、100%;MBR采用浸没式中空纤维膜,双层膜架,在线清洗,设计膜通量为18.8 L/(m^(2)·h);吨水工程费用为2 250元/m^(3),其中设备购置费占40%。投入运行后,应对碳源不足时在缺氧池投加葡萄糖,当生物除磷效果不佳时在好氧池末端投加聚合氯化铝,实际出水水质可稳定达标。

The influent of a wastewater treatment plant in Maoming mainly consists of urban domestic sewage,with a design capacity of 4.5×10^(4) m^(3)/d.The effluent quality is required to meet the quasi‑classⅣlimit specified in Environmental Quality Standards for Surface Water(GB 3838-2002)(except TN),and achieves a remarkable 95%removal rates for BOD_(5),suspended solids(SS)and ammonia nitrogen(NH_(4)^(+)-N).The land use index is 0.35 m^(2)(/m^(3)·d^(-1)),which is only 1/3 of the recommended value in the relevant code.To comply with the effluent quality requirements and land use restrictions,the main process employed AAO+MBR,which demonstrated a significant reduction in land usage compared to the coagulation and precipitation advanced treatment process.The design sludge load for the biochemical tank was 0.065 kgBOD_(5)/(kgMLSS·d),the design sludge concentration for the aerobic tank was 9000 mg/L,and the design gas‑water ratio was 4.9∶1.The three‑stage sludge reflux system was utilized,with design reflux ratios of 300%,200%,and 100%for each stage respectively.The membrane in MBR featured an immersed hollow fiber structure,a double‑layer membrane frame,online cleaning,and a designed membrane flux of 18.8 L/(m^(2)·h).The project cost was 2250 yuan/m^(3),with equipment purchase cost accounting for 40%.After commissioning,glucose was added to the anoxic tank in case of insufficient carbon source,and polyaluminum chloride was dosed at the end of the aerobic tank if the biological phosphorus removal performance was unsatisfactory,ensuring stable effluent quality that met the discharge standard.