DO对膜曝气生物反应器同步除碳脱氮的影响

Effect of DO on simultaneous removal of carbon and nitrogen by a membrane aerated bioreactor

为获得膜曝气生物反应器(membrane aerated bioreactor,MABR)处理污水同步除碳脱氮的最佳DO质量浓度,构建以亲水性聚丙烯中空纤维膜为曝气膜组件的MABR,在80 d连续运行的时间内,考察DO质量浓度对MABR处理模拟生活污水同步除碳脱氮效果的影响.结果表明:在水力停留时间8 h、膜表面COD及TN负荷分别为3.7 g.m2.h-1(COD计)和0.36 g.m2.h-1(TN计)相对稳定的条件下,当混合液DO质量浓度为0.5 mg/L左右时,MABR能实现较好地同步除碳脱氮,此时对COD、NH4+-N和TN去除率分别为80%、86.4%和66.5%;当DO质量浓度分别为4 mg/L和2 mg/L左右时,对COD和NH4+-N的去除率均提高到88%以上,但反硝化受到限制,TN去除效果不佳,去除率分别为10%和24%;当DO质量浓度降至0.1 mg/L左右时,MABR对COD和NH4+-N的去除均受到限制,去除率分别为60%和57.4%,TN去除率为46.8%.

In order to achieve an optimum DO for simultaneous carbon and nitrogen removal by the Membrane Aerated Bioreactor（MABR）treating wastewater,a MABR in which the hydrophilic polypropylene hollow-fiber membrane module was used was constructed,and the effect of DO on simultaneous removal of carbon and nitrogen by MABR treating synthetic wastewater was investigated during the 80 days＇ continuous operation.The results show that under the relative stable condition that hydraulic retention time（HRT）was 8 h,and the membrane surface loading rate was 3.7 g·m-2·h-1（COD）or 0.36 g·m-2·h-1（TN）,MABR realized preferable simultaneous removal of carbon and nitrogen when DO was 0.5 mg/L around.The removal rate of COD,NH4＋-N and TN was 80%,86.4% and 66.5%,respectively.When DO was 4 mg/L or 2 mg/L around,both COD and NH4＋-N removal rate rose to more than 88%,but denitrification was limited,which resulted in a poor TN removal,with the former TN removal rate being 10% and the latter 24%.When DO dropped to 0.1 mg/L around,COD and NH4＋-N removal rate decreased to 60% and 57.4%,respectively,and TN removal rate also decreased to 46.8%.It was suggested that DO in the mixed liquor of MABR should be controlled at 0.5 mg/L around for an effective simultaneous carbon and nitrogen removal.