倒置A^2/O工艺在城市污水处理中的生产性应用

Full-scale application of reversed A^2/O process in Qingtan municipal sewage treatment plant

常州市清潭污水处理厂四期工程在A2/O工艺设计的基础上,采用停止内回流,加大污泥回流比的倒置A2/O工艺运行.两年多的运行实践表明:在MLSS为3.5～4.5g/L;SVI为80～140mL/g;污泥负荷为0.08～0.15kgBOD5/(kgMLSS.d);有机负荷为0.20～0.35kgCOD/(kgMLSS.d),泥龄11～20d条件下,污水CODCr、BOD5、SS、NH3-N和TP的去除率分别高达97.6%、94.4%、95.9%、98.0%和93.3%,出水水质符合GB18918-2002中一级排放标准的要求.认为该工艺对氨氮和总磷的冲击负荷抗受能力强,并提出了该工艺需进一步研究.

The phase Ⅳ project of Qintan Municipal Sewage Plant in Changzhou city has been designed as the conventional A^2/O process, and operated as the reversed A^2/O process which cancels the reflux of mixed liquid and increases the reflux ratio of sludge. It was demonstrated by the operation for over two years that the removal efficiencies of COD_(Cr), BOD_5, SS, NH_3-N and TP are respectively 94.8%,97.9%,94.8%,97.8% and 91.7% under the condition of MLSS;3.5～4.5 g/L, SVI:80～140 mL/g, sludge loading:0.08～0.15 kg BOD_5/(kgMLSS·d),organic loading:0.20～0.35 kgCOD/(kgMLSS·d),sludge age:11～20 d. Effluent reaches the first class discharge standard in GB18918-2002. The reversed A^2/O process can dramatically remove ammonia nitrogen and total phosphorus, and some problems deserved to be discussed forwardly.