核黄素强化IFAS工艺脱氮同步降解布洛芬研究

Study of enhanced nitrogen removal and simultaneous degradation of ibuprofen in IFAS process by riboflavin

城市污水厂中传统脱氮工艺脱氮效果差以及对药物及个人护理品(pharmaceutical and personal care products,PPCPs)降解效率低,导致出水氮超标的同时频繁检出PPCPs.以布洛芬(ibuprofen,IBP)作为典型PPCPs,以泡沫炭作为微生物及核黄素载体,以核黄素作为氧化还原介体强化生物膜-活性污泥组合(integrated fixed-film activated sludge,IFAS)工艺脱氮同步降解IBP,并探究其作用机理.结果表明,微氧条件下,脱氮与IBP降解能够同步进行,碳氮比(COD/NO_(3)^(-)-N)为4∶1、水力停留时间为6 h时核黄素强化反应器(R2)中硝氮平均去除率及IBP平均降解率相较于空白对照反应器(R1)分别提高了36%和25%.机理研究表明,R2中核黄素促进了脱氢酶与反硝化酶的活性,生物膜的脱氢酶、硝酸盐还原酶和亚硝酸盐还原酶活性平均值分别较R1提高了35%、14%、35%,从而实现了核黄素强化IFAS工艺脱氮同步降解布洛芬.

Conventional nitrogen removal processes in municipal wastewater plants have low removal efficiency of nitrogen and low degradation efficiency of pharmaceutical and personal care products(PPCPs),resulting in frequent detection of PPCPs and nitrogen excess in effluent.Ibuprofen(IBP)is exemplified as a typical PPCP,and foam carbon and riboflavin are applied as microbial and riboflavin carrier and redox mediator,respectively.The above procedure is done to achieve simultaneous nitrogen removal and IBP degradation in the enhanced IFAS(integrated fixed-film activated sludge)process and investigate the mechanism of action.The results show that the removal of nitrogen and the degradation of IBP can proceed simultaneously under microaerobic conditions.Under the conditions of 4∶1 of carbon to nitrogen ratio(COD/NO_(3)^(-)-N)and 6 h of hydraulic retention time,the average nitrate nitrogen removal rate and the average IBP degradation rate in reactor R2(enhanced by riboflavin)are 36%and 25%higher than those in reactor R1(blank control),respectively.The mechanism study shows that riboflavin in R2 promotes dehydrogenase and denitrifying enzyme activities.Compared to R1,the average activities of biofilm dehydrogenase,nitrate reductase and nitrite reductase in R2 increase by 35%,14%and 35%,respectively.Thereby,enhanced nitrogen removal and simultaneous degradation of IBP in IFAS process by riboflavin is achieved.