CASS工艺园区污水处理厂提标改造为AAO+三级处理工艺后的运行效果对比分析

Contrastive analysis of operation effect of the park sewage treatment plant with the upgraded and reconstructed AAO-tertiary treatment process from CASS process

为深入落实长江大保护政策,对南京经济技术开发区污水处理厂实施了提标改造。提标工艺为粗细格栅+曝气沉砂池+AAO+高效沉淀池+滤布滤池+消毒。结果表明:在该工艺运行过程中,进水可部分选择性地或全部越过厌氧池进入缺氧池,从而强化反硝化脱氮;在好氧池池末端前置投加除磷药剂,不仅可去除一定的COD和TP,还有强化二沉池污泥压缩、泥水分离的效果;借助碳源投加可提高来水可生化性;增加一套占地面积小、处理效果稳定的高效沉淀池+滤布滤池+消毒三级处理工艺,可控制出水水质,使其持续稳定达标;提标后出水COD、TP、TN、NH3-N、SS的平均质量浓度分别由37.9、0.323、11.18、1.94、19 mg·L-1降低至22.3、0.029、4.55、0.08、3 mg·L-1,污水直接处理成本由0.47元·t-1增加到0.78元·t-1;提标后出水水质稳定达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准,部分指标满足《地表水环境质量标准》(GB 3838-2002)Ⅳ类水标准要求。该提标改造项目的实施经济效益可行、社会效益显著,可为同类型污水处理厂提标改造工作提供参考。

In order to implement the Yangtze River protection policy deeply, the upgrading and reconstruction of sewage treatment plant in Nanjing Economic and Technological development zone were carried out. The upgraded process was coarse and fine grid+aerated grit chambers+AAO+high efficient sedimentation tank+cloth filter+disinfection. The results showed that a partial or total influent could selectively cross the anaerobic tank and enter the anoxic tank to enhance denitrification during process running;The dephosphorization agent predosed at the end of aerobic tank could not only remove COD and TP, but also strengthen sludge compression and water-sludge separation in secondary sedimentation tank. Carbon source addition could improve the biodegradability of influent. The tertiary treatment process of high efficient sedimentation tank+filter cloth filter+disinfection with small footprint and stable treatment effect could control the effluent quality which could continuously meet the discharge standard. After upgrading, the average mass concentrations of COD, TP, TN,NH3-N, SS in effluent decreased from 37.9, 0.323, 11.18, 1.94, 19 mg·L-1 to 22.3, 0.029, 4.55, 0.08, 3 mg·L-1,respectively. The direct sewage treatment cost increased from 0.47 to 0.78 yuan t-1. The effluent quality met the first level A standard of pollutant discharge standard for municipal sewage treatment plants(GB 18918-2002),some water quality indexes met the requirements of the grade Ⅳ of surface water environmental quality standard(GB 3838-2002). This project had feasible economic and remarkable social benefits, which could provide reference for the upgrading and reconstruction of the same-type sewage treatment plants.