铁炭微电解+UASB+MBR组合工艺处理DHA废水

Treatment of DHA wastewater by combined process of ferric-carbon microelectrolysis+UASB+MBR

以铁炭微电解作为预处理,采用升流式厌氧污泥床(UASB)和膜生物反应器(MBR)串联的方式降解二十二碳六烯酸(DHA)合成所产生的高浓度有机废水。通过单因素试验和正交试验获得了铁炭微电解反应的最佳工况:pH为3,反应时间为4 h,铁炭比为3∶1,搅拌强度为250 r/min。在最佳工况下,铁炭微电解可降低DHA原水中45%的化学需氧量(COD),且BOD_(5)/COD值由0.10提升至0.31,改善了废水的可生化性。UASB反应器的最大容积负荷可达8 kgCOD/(m^(3)·d),出水COD浓度稳定在1 500 mg/L,COD去除率高于80%。UASB反应器出水直接通入MBR,MBR容积负荷为1.5 kgCOD/(m^(3)·d),出水COD浓度为80 mg/L左右,氨氮浓度低于5 mg/L,满足《污水排入城镇下水道水质标准》(CJ 343-2010)标准。

In this paper, the ferric-carbon micro-electrolysis was used as pretreatment, coupled with up-flow anaerobic sludge bed(UASB) and membrane bioreactor(MBR) to process the high concentration organic wastewater from the synthesis of docosahexaenoic acid(DHA). According to the single factor test and orthogonal test, the paper obtained the optimal conditions of iron carbon micro electrolysis reaction: pH=3, 4 h of reaction time, 3∶1 of iron carbon ratio, 250 r/min of stirring intensity. Under the optimal conditions, the chemical oxygen demand(COD) of DHA wastewater could be reduced about 45%, and the value of BOD_(5)/COD was increased from 0.10 to 0.31, which improved the biodegradability of wastewater. In this study, the maximum volume loading of UASB reactor was 8 kg COD/(m^(3)·d), the COD concentration in effluent was stable at 1 500 mg/L, and the COD removal rate was higher than 80%. The volume loading of MBR was 1.5 kg COD/(m^(3)·d), the concentration of COD in effluent was about 80 mg/L, and the concentration of ammonia was less than 5 mg/L, which meets the requirement of Water Quality Standards for Waste Water Discharge into MunicipalSewers(CJ 343-2010).