Study On Nitrogen And Phosphorus Removal Efficiency With Electricity Generation Of Domestic Sewage In Dual-Cathode Microbial Fuel Cells

Nitrogen and phosphorus pollution in wastewater is a global environmental problem.They are widely found in aquaculture wastewater and domestic sewage,which leads to the problem of eutrophication.Conventional wastewater treatment requires additional carbon and power inputs to maintain high removal efficiency,which increases the cost of processing.Microbial fuel cell(MFC)is a device that uses microorganisms as catalysts to convert organic chemical energy into electrical energy in wastewater directly.In this study,a double cathode MFC system was constructed to realize the degradation of wastewater organic matter,the simultaneous production of nitrogen and phosphorus,and the theoretical basis for wastewater treatment and reuse.The double cathode MFC system has been successfully started by manual simulation of wastewater.After 33 d operation,the maximum instantaneous voltage of the system has exceeded 812 mV,the internal resistance value is 113.7 ?,and the maximum power density reaches 3.24 W/m3.The experimental results show that the removal efficiency of organic pollutants and nitrogen and phosphorus pollutants in the double cathode MFC system is better than that of the non production system.This shows that the introduction of bioelectricity can enhance the degradation of pollutants in the system.In two kinds of anaerobic anoxic aerobic and anaerobic aerobic anoxic operation mode,using artificial water and wastewater influent,the changes of the double cathode MFC system the indoor pollutants over time,and compared with the non electricity generation system.Studies have shown that ammonia is mainly removed in the anaerobic and aerobic chambers.The anaerobic aerobic anoxic model is slightly better than the anaerobic anoxic aerobic model in total nitrogen removal.Under the two operating modes,the removal efficiency of total phosphorus in each polar chamber of the system was more consistent,and the total phosphorus was mainly removed in the aerobic chamber.It is found that the anaerobic aerobic anoxic operation mode has better effect on nitrogen removal,so the operation parameters of the system are optimized.It was found that the appropriate hydraulic retention time can improve the removal rate of organic matter,ammonia nitrogen and total nitrogen in sewage,and the reasonable hydraulic retention time is 20 h in this experiment.The removal rate of ammonia nitrogen and total nitrogen of the system increased first and then decreased with the increase of influent load,and the optimal influent load was 250 mg/L.The production efficiency of the system is greatly affected by influent pH,while under acidic conditions,the performance of electricity generation is obviously suppressed,and the influent is neutralor weak alkaline.The microbial community structure in the polar compartments of the double cathode MFC system was analyzed by Illumina high throughput sequencing.Through the analysis of microbial community composition,it is found that there are a large number of bacteria related to electricity production in the polar chamber,and the existence of these bacteria producing bacteria is the biological basis for the system to produce good electricity production effects.At the same time,there are some bacteria related to nitrogen and phosphorus removal in the reactor.These strains can promote the removal of nitrogen and phosphorus in the double cathode MFC system.