Comparative Study On The Performance Of Two Kinds Of Wastewater Treated By MFC Under Different Hydraulic Retention Time

Microbial fuel cell(MFC)is a new application direction of using microorganisms to treat sewage.Can handle organic wastewater and heavy metal wastewater and generate electricity at the same time.Because of its advantages such as cleanness and environmental protection,simple structure and stable system capacity,it has broad application prospects.In this study,a new continuous flow microbial fuel cell was constructed by upgrading the conventional intermittent microbial fuel cell and connecting the CSTR reactor in series.In anaerobic conditions,the power generation and decontamination effects of molasses wastewater and beer wastewater as anode substrates and silver nitrate solution as cathode filling solution were investigated under different HRT.In this experiment,the water flow rate is controlled by adjusting the speed of the inlet pump,and then the hydraulic retention time(HRT)is changed to 24 h,20 h,16 h,12 h,and 8 h,respectively.At the same time,the output voltage of the MFC is measured.The measured voltage value can reflect the power generation performance of the MFC system,and the measured COD value can reflect the decontamination performance.In addition,it can also compare the power generation and decontamination of the system when molasses wastewater and beer wastewater are anode substrates.Through experimental research,it was found that with the extension of HRT,the voltage of molasses wastewater and beer wastewater increased first and then decreased.When the HRT is 16 h,the stable voltage of the system is the largest.Among them,molasses wastewater was 195.7 mV,and beer wastewater was 165.7 mV.The COD removal rate increased with the extension of HRT.When the HRT was 24 h,the maximum COD removal rates were 58.36%and 53.95%,respectively.And when HRT is 16h,comparing the stable voltage and maximum COD removal rate of molasses wastewater and beer wastewater,it is found that when HRT is 16h,the stable voltage of molasses wastewater is 195.7mV,and the highest COD removal rate is 47.62%;The voltage was 165.7mV,and the COD removal rate was 43.05%at the highest.The electric performance and decontamination effect of molasses wastewater as anode substrate were higher than that of beer wastewater.Therefore,reasonable selection of HRT is necessary for the performance of microbial fuel cells.