Removal Efficiency And Mechanismof Typical Ppcps In Microbial Fuel Cell Coupled With Constructed Wetlands

Pharmaceuticals and personal care products（PPCPs）,as a massly-used and potentially physiological effective,new chemicals,produced by human-living activities,industry,medicine and PPCPs manufacturing,has received a common attention by scientific field as well as society.PPCPs enter the water environment directly or indirectly through various mediums such as water,atmosphere and soil,posting lasting threat to human,flora and fauna and the environment.As water is the largest storage space,multiple researches have been done on PPCPs in water internationally.Ibuprofen（IBP）and bisphenol A（BPA）,two of the most widely used PPCPs,were selected as the typical medicine for study.Constructed wetland（CW）,possessing the favorable structure condition for constructing microbial fuel cell（MFC）and the potential decontamination ability for removing refractory organics,was equipped with MFC for the degradation of PPCPs.CW and MFC-CW systems were successfully formatted,and maintained stable for over half a year.By evaluating the efficiency of power generating,COD,NH₄⁺-N and PPCPs removal,this paper investigated the promotion of CW coupling with MFC.The influence of PPCPs and HRT on MFC-CW was also estimated.The degrading path of PPCPs was speculated,using LC-MS to detect the intermediate products of PPCPs.Several ecological methods such as high throughout sequencing were taken to explore the microbial structure in CW and MFC-CW.Main research achievements are as followings:Under the same water conditions,the COD,NH₄⁺-N and PPCPs removal efficiency and microbial richness of MFC-CW were better than CW.The link of circuit had remarkable improvement on both substrate and PPCPs removing and microbial richness,as is to say,the introduction of MFC enhanced the treatment effect of CW.The introducion of MFC could also influence the microbial structure,as Proteobacteria and Firmicutes,two commen electricity production bacteria,were more enriched in MFC-CW.At the beginning of system setup,all the systems could achieve 95%of PPCPs removal efficiency.After the stabilization of system,the the removal efficiency of IBP was still higher than that of BPA for the possible reason that IBP only have one benzene ring which was more easily micro-biologically degradable.The inoculation of IBP did not have evident impact on the removal efficiency of COD and NH₄⁺-N while the inoculation of BPA hindered the systems.The result of high throughout sequencing showed that the inoculation of IBP and BPA both affected the microbial structure.HRT had significant influence on the performance of MFC-CW.With the extension of HRT,the internal resistance and coulombic efficiency of MFC showed a gradually increasing trend while the power density showed a decreasing trend.At the same time,the COD,NH₄⁺-N and PPCPs removal efficiency and microbial richness of MFC-CW were promoted with the extension of HRT.The microbial structure showed great difference under different HRT,as the electrochemically active microorganisms were more easily to grow under longer HRT.During the degradation of IBP,intermediate products,C₈H₈O₂、C₇H₆O₄ and C₁₃H₁₈O_3,were detected,among which 1-Hydroxyibuprofen and 2-Hydroxyibuprofen have similar toxicity posting potential threat to the environment.During the degradation of BPA two intermediate products of C₇H₆O₄ and C₁₅H₁₃O_4,were detected.