Study On Constructed Wetland-MFC Technology In Organic Degradation And Electricity Generation Performance

A constructed wetland-microbial fuel cell hybrid system（CW-MFC）was constructed.CW-MFC and CW were used as carriers and nitrobenzene as target pollutants to establish experimental models.With the same hydraulic retention time（HRT）,the treatment effects of four different nitrobenzene concentrations and aniline degradation products in different structural layers were studied.The results showed that with the extension of HRT,the removal rate of nitrobenzene in CW-MFC system increased rapidly at first,then slowed down,and finally tended to balance.The overall removal rate of nitrobenzene in CW-MFC system was more than 85%.Nitrobenzene was continuously reduced at the cathode of CW-MFC system and aniline was oxidized at the anode of CW-MFC system.Anode system played a major role in the treatment of aniline and nitrobenzene,which was better than cathode and anode intermediate layer.CW-MFC had a good removal effect on aniline,which was the product of nitrobenzene production,and could realize the degradation of aniline.By changing HRT,the removal effects of CW-MFC and CW on different influent concentration of nitrobenzene and COD were compared.The results showed that the removal and degradation effect of CW-MFC on nitrobenzene and aniline was better than that of CW;with the increase of influent concentration of nitrobenzene,the degradation effect gradually decreased;higher concentration of nitrobenzene could inhibit microorganisms at the anode;CW-MFC had better COD treatment effect than that of CW.The optimum condition of degradation of nitrobenzene in CW-MFC and CW systems was that HRT was 120 h.By comparing the degradation of nitrobenzene,aniline and COD in CW-MFC and CW systems,it could be concluded that MFC could promote the treatment of simulated nitrobenzene wastewater in CW systems.The daily voltage and power density of CW-MFC system were recorded,and the power generation performance of four stages of CW-MFC system was studied.The average generation voltages of the four stages were 380V,430V,415V and 390V,respectively.The minimum internal resistance was 451.3Ω,the maximum internal resistance was 524.96Ω,the maximum power density was 87.47m W/m³,and the maximum coulomb efficiency was 0.72%.When the concentration of nitrobenzene was lower than 65 mg/L,the microbial activity at the anode was normal,which could keep the microbial fuel cell system running steadily.When the nitrobenzene concentration was88mg/L,the active part of the microorganism was inhibited.Using kinetic Haldane model,the kinetic parameters were calculated:?_max（28）0.118911（/h）,Ks（28）15.7mg/L,Ki（28）198.22mg/L,R²（28）0.97,REMC（28）.001012.When nitrobenzene concentration was less than 88mg/L,the biodegradation process of nitrobenzene accorded with first-order kinetic model.Figure 44;Table 8;Reference 80...