CAST工艺的脱氮除磷强化改造

浙江某城镇污水处理厂对上游工业园区的工业废水进行纳管后,工业废水比例增大,进水的污染物比例发生变化,碳、氮、磷营养比例失调,造成污水处理厂在运行过程中出水TN和TP不能稳定达标,为此采取改造缺氧池、曝气系统、混合液回流系统和优化运行模式等措施对污水处理厂进行脱氮除磷强化。改造后运行结果表明,出水TN和TP分别为3.43~14.47 mg/L和0.004~0.481 mg/L,稳定达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准。

Improvement of Nitrogen and Phosphorus Removal in CAST Process

After the industrial wastewater of an upstream industrial park enters a municipal wastewater treatment plant in Zhejiang,the increasing proportion of industrial wastewater causes the variation of influent pollutants ratio,imbalance of carbon to nutrients ratio,and unstable compliance of effluent TN and TP.Thus wastewater treatment plant was retrofitted through the transformation of anoxic tank,aeration system,mixing liquid reflux system and the optimization of operation mode to enhance phosphorus and nitrogen removal.The operation results after reconstruction showed that the effluent TN and TP were 3.43-14.47 mg/L and 0.004-0.481 mg/L,which stably reached the first level A requirements of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant( GB 18918-2002).