分段进水生物接触氧化工艺净化河道水质的旁路示范工程研究

Bypass Demonstration Work of the Step-Feeding Biological Contact Oxidation Process for River Water Purification

针对滇池流域污染最严重的大清河,采用分段进水生物接触氧化工艺(SBCOP)开展河道水体的旁路处理示范工程研究。SBCOP示范工程的设计规模为1000m3/d,水力停留时间(HRT)为4.75h。2007年11月至2008年3月冬旱季期间,根据气候和进水水质条件调节分段进水比和气水比,示范工程共计运行了3种工况。研究结果表明:SBCOP示范工程对COD和NH4+-N具有较好的去除效果,平均去除率为37.7%和32.9%,1∶1∶1的分段进水比利于去除COD和NH4+-N,NH4+-N去除率随进水NH4+-N浓度升高而降低;受到低温、低碳源、高进水DO浓度和生物膜生长不佳等因素影响,TN去除效果较差,平均去除率为10.5%;TP的平均去除率为13.7%,由于示范工程未设排泥设施,TP的去除主要依靠底泥吸附和水绵吸收来实现,及时清除底泥和死亡的水绵利于去除TP。进水为滇池湖水时,气水比为2∶1可以维持一定的去除效果。

The Daqing River is the most seriously polluted river in the Dianchi Lake watershed. A bypass demonstration work of step-feeding biological contact oxidation process （SBCOP）, with the treatment scale of 1000m^3/day and the hydraulic retention time （HRT） of 4.75 hours, was built around the river bank to purify the river water. During the winter dry season from Nov. 2007 to Mar. 2008, three sets of parameters of the demonstration work were operated by regulating step-feedlng ratio and air-water rate according to the influent qualities and climatic conditions. The results show that the SBCOP demonstration work kept good removal efficiencies for COD and NH^＋4 -N, and the average removal rates were 37.3% and 32.9% each. The step-feeding ratio of 1 ： 1 ： 1 was beneficial for removing COD and NH^＋4 -N. The removal rate of NH^＋4 -N decreased when the concentration of NH^＋4 -N increased. The average removal rate of TN was as low as 10.5 %, owing to the negative impacts of low temperature, carbon source shortage, high DO level of the influent, and loose and porous biofilm. The removal of TP depended on the deposition of sludge and adsorption of Spirogyra sp., and the average removal rate of TP was 13.7% . To avoid the minus removal rate of TP, sludge discharge and removing of dead Spirogyra sp. were needed. The air-water rate of 2 ： 1 was suitable when influent was Dianchi Lake water.