污水处理厂CANON工艺小试

在污水处理厂进行CANON工艺小试.试验以污水处理厂A/O除磷工艺出水为基质,启动并运行CANON生物滤柱.第48 d时,反应器氨氮去除率连续10 d大于90%,总氮去除率在70%以上,CANON生物滤柱启动成功.第49~129 d,反应器内部DO控制在较低水平(0.2~0.5 mg·L~(-1)),出水几乎不含氨氮.最大出水总氮浓度为15.6 mg·L~(-1),超过一级A排放标准,硝化细菌(NOB)出现了过量增殖的现象.第129、169和213 d对滤柱进行反冲洗,使得反应器长期总氮去除率大于70%,出水总氮浓度小于12 mg·L~(-1).出水氨氮和总氮浓度达到了一级A标准,硝化细菌得到了有效抑制.结果表明,反冲洗几乎不会影响滤层结构,对滤料生物膜厚度和功能微生物活性影响较小,对硝化细菌抑制作用较大.在实际工程应用中可以通过定期反冲洗维持CANON工艺稳定运行.

Laboratory-scale CANON Processes Applied to Wastewater Treatment Plants

A laboratory-scale completely autotrophic nitrogen removal over nitrite (CANON) process was operated in a municipal wastewater treatment plant (WWTP). Sewage effluent treated by the anaerobic/oxic (A/O) process and was used to operate a WWTP to obtain the initial substance for the start-up of a CANON filter reactor. On the 48th day, the ammonia removal rate was measured at greater than 90% in successive 10 d samples and the nitrogen removal rate was greater than 70%. The CANON filter was successful at start up. From the 49^th to the 129^th day, the dissolved oxygen in the reactor was maintained at fairly low concentration of 0.2-0.5 mg·L^-1. The effluent contained nearly no ammonia and the maximum total nitrogen (TN) concentration was 15.6 mg·L^-1, which exceeded the national Class 1A Discharge Standards for pollutants from municipal wastewater treatment plants. Nitrite oxidizing bacteria (NOB) proliferated excessively in the reactor. Backwash was implemented on 129th, 169th and 213th days. The nitrogen removal rate was more than 70% for a long time and TN concentration in effluent was below 12 mg·L^-1. The nitrogen concentration in effluent fitted the national Class 1A Discharge Standards and the NOB were effectively inhibited. These results show that backwash has negligible on the structure of filter and its impact on the thickness of the bio-membrane and its functional bacteria was small, however, it is capable of effectively inhibiting the activity of the NOB. Periodically backwashing can be utilized as an engineering application to maintain stable operation of the CANON process.