Study On The Influencing Factors And The Resource Of Energy Recovery Of The Urine Treated By BES

At present,the world is faced with pollution and shortage of energy and resources.Urine,as a liquid closely related to human life,only accounts for 1%of the total domestic sewage,which not only contains a lot of organic matter,but also contains 75%and 50%of nitrogen and phosphorus.But urine is neglected and discarded in everyday life.On the contrary,the discharge into urban sewers under the action of a large amount of flushing water not only causes waste of resources,but also increases the pollution load of water environment.Bioelectrochemical technology not only can remove pollutants but also can recover energy.Therefore,in this paper,two forms of the bioelectrochemical system?BES?microbial electrolysis cell?MEC?and microbial fuel cell?MFC?were used to study the resource utilization of BES in the treatment of urine pollution,productivity and energy recovery.The main research contents are as follows:1)BES was initiated by using simulated urine in a two-compartment MFC at different concentrations of inoculating sludge.The results showed that the BES system could be started and stabilized by increasing the sludge concentration.When the total amount of microorganisms was small,the MFC took a long time to reach the highest voltage with stable output,and the sludge concentration was equal to or higher than 5183mg·L^-1,the microbial base was large and the growth and reproduction was rapid,which only took about 160h.When the sludge concentration was too high,the internal resistance of the system would be increased,thus affecting the output power of the battery.When the sludge concentration was 5183mg·L^-1,the electrical performance of MFC was the best,and the output voltage was up to 0.78V.2)Based on the successful start-up of the system,the research on the capacity of pH and concentration in two-compartment urine MFC decontamination was explored.The results showed that the output voltage and pollutant removal rate were positively correlated with pH,and pH=9 was a more appropriate pH.When the dilution ratio of urine water was changed from 10 times to 3 times,the ability of microbial degradation of organic matter and the efficiency of electron transfer were increased,resulting in 1.5 times of output voltage,98%removal rate of pollutants,and 400%increase in energy recovery.3)The effects of different factors on the urine treatment performance of two-compartment MEC were also investigated.The results showed that increasing the applied voltage of MEC was helpful to improve the treatment effect of MEC,but too high voltage will reduce the activity of microorganism,and 0.8v was the appropriate applied voltage of MEC.When the concentration of influent urine was too high,the concentration of ammonia nitrogen was too high,which would reduce the activity of anode microorganisms and thus affected the reaction effect.The suitable concentration of cathode PBS was 100mM.In the optimized operation,both COD and ammonia nitrogen had better removal effects,and the hydrogen production rate reached 0.23±0.02m³H₂MEC·m^-3d^-1,and the total energy recovery efficiency was 25.8%.4)Finally,on the basis of the above studies,the communities of MEC and MFC and the resource effect of productivity were analyzed.The dominant fungi of the MEC anode system were Aminivibrio and Pseudomonas;The dominant bacteria of the MFC anode system were synergistes,Aminivibrio,Mesotoga and Pseudomonas.Aminivibrio and synergistes were the main fermented bacteria,which provided a good electro-production matrix for the production of electricity in electrochemical systems.Pseudomonas and Mesotoga were the main producing microorganisms in the electrochemical systems of MEC and MFC,respectively.The treatment of urine by BES under the action of microorganism can obtain certain resource efficiency.Further improvements are needed.