| The high ammonia nitrogen wastewater has a wide range of sources and hazards.It has become a hot spot to study the dispersible treatment of high ammonia nitrogen wastewater in rural areas.Microbial electrochemical system(MES)is widely used in energy,environmental ecology and wastewater treatment because of its many advantages such as generating clean energy,degrading organic pollutants and being easy to maintain and manage.However,there is still a lack of systematic research in the process of treating high ammonia nitrogen wastewater by biocathode microbial electrochemical system.In this study,the biocathode microbial electrochemical system was constructed to analyze its performance under different ammonia nitrogen loading,so as to further explore the optimal operating parameters of the system and lay a foundation for large-scale system.In this paper,2 L dual-chamber biocathode microbial electrochemical system were constructed to study the performance of the system under the loading of low ammonia nitrogen(50 mg/L)and high ammonia nitrogen(450 mg/L).Compared with start-up of the system under low ammonia-nitrogen loading,start-up of the system under high ammonia nitrogen loading had lower output voltage,cathode potential and output power,indicating that the ammonia nitrogen concentration of450 mg/L inhibited the electricity production performance of the system.The COD removal rate of the system under high ammonia nitrogen loading was lower than that of the system under low ammonia nitrogen loading.The total nitrogen removal rate,ammonia nitrogen removal rate and nitrate nitrogen conversion rate of the system under high ammonia nitrogen loading during the adaptation period were higher than the start-up stage.In addition,the structure and abundance of microbial communities of the cathode and anode in the two systems were quite different,indicating that the microorganisms in the system were susceptible to high ammonia nitrogen loading.By increasing the ammonia nitrogen loading step by step to study the performance of the system under different ammonia nitrogen loading,it could find that the COD removal rate of the system had been maintained above 82% under various ammonia nitrogen concentrations,indicating that the ability of the system to remove organic matter had not been greatly attenuated.The output voltage,output current,cathode potential and maximum power density point of the system at 450mg/L ammonia nitrogen concentration were greatly reduced,indicating that the ammonia nitrogen concentration had a serious inhibitory effect on the biocathode electrochemical system,and mainly suppressed the cathode.The mainly limited step of treating high ammonia nitrogen wastewater in biocathode electrochemical system was cathode.When the ammonia nitrogen loading was increased,the abundance of the denitrification function bacteria and the electrogenic bacteria in the system were reduced,which explained the reason for the decline of the system’s electricity generation performance and nitrogen removal performance to some extent.In order to eliminate the influence of potential on electrode microbial community and electrochemical activity,constructing a biocathode three-electrode system and then setting a constant potential,it could study the effect of ammonia nitrogen on biocathode performance by gradually increasing the ammonia nitrogen concentration.The output current of the system began to decrease at 300 mg/L ammonia nitrogen concentration.The output current of the system was reduced by about half at 450 mg/L ammonia nitrogen concentration.And high ammonia nitrogen had a significant inhibitory effect.At the same time,the reduction current of the system also decreased significantly,and high ammonia nitrogen inhibited the electrochemical activity of the system. |
