电化学工艺处理滇池流域农业面源污水

Electrochemical Process for Treatment of Agricultural Non-point Source Sewage in Dianchi Basin

设计了一套电化学脱氮除磷系统,在滇池流域某水质净化厂进行中试,探讨了该系统对农业面源污水中COD、TP、NH_(3)-N、TN的去除效果,并考察水力停留时间(HRT)及电解质对强化脱氮的影响。结果表明,在电流强度为5 A、极板间距为7 cm、极板数量为6对、HRT为6 h的条件下,电化学工艺对COD、TP、NH_(3)-N及TN的去除率分别为65.9%、79.9%、8.1%和6.8%,其中出水COD、TP满足《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准,且出水TP浓度可满足滇池流域磷的提标要求(<0.3 mg/L),但脱氮效果不理想。当HRT为20 h、NaCl投加量为3000 mg/L时,对NH_(3)-N、TN的去除率分别提升至48.5%、45.2%,但仍未达到排放标准。该电化学工艺对去除有机物和磷具有优异性,而脱氮方面仍有待进一步优化。

A set of electrochemical nitrogen and phosphorus removal system was designed,and a pilot-scale device was built in a wastewater purification plant in Dianchi basin.The removal of COD,TP,NH_(3)-N and TN from agricultural non-point source sewage was discussed,and the effects of hydraulic retention time(HRT)and electrolyte on enhanced nitrogen removal were investigated.Under the following conditions:current intensity of 5 A,plate spacing of 7 cm,plate number of 6 pairs and HRT of 6 h,the removal efficiencies of COD,TP,NH_(3)-N and TN were 65.9%,79.9%,8.1%and 6.8%,respectively.Among them,the COD and TP in effluent met the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918-2002),and the TP in effluent even met the requirements of phosphorus discharge in Dianchi basin(less than 0.3 mg/L).However,the denitrification performance was poor.When HRT and NaCl dosage were 20 h and 3000 mg/L,the removal efficiencies of NH_(3)-N and TN were increased to 48.5%and 45.2%,respectively,but they still failed to meet the discharge standard.The electrochemical process had an excellent performance in the removal of organic matter and phosphorus.However,the nitrogen removal needs to be further optimized.