The Pollutant Removal And Electricity Generation Performance Of Microbial Fuel Cell And Its Control Strategies

The microbial fuel cell(MFC)technology offers sustainable solutions for distributed power systems and energy positive wastewater treatment,which attracted more and more attention in recent years.However,the power density of MFCs is too low and unstable,which is still in the level of laboratory research.Because of the bioelectrochemical reaction in MFC system is a highly complex,serious nonlinear and time-delay dynamic process,the experimental research for the electrochemical parameters is still a considerable challenge.In this paper,the dynamic performance,energy harvesting technology and denitrification of microbial fuel cell are studied by combining theory with experiment.First of all,a continuous flow MFC model is developed to study the influence of several controllable parameters on the output performance of the MFC.Results show that the anode reaction is the main impact factor of MFC performance and cathodic reaction is a key factor affecting system stability.The power production performance of MFC can be improved by regulating the feed flowrate periodically and increasing the concentration of acetate and bacteria.A increase in Air-saturated water flowrate leads to a higher reliability and stability.This study offers a theoretical foundation for the optimization of experimental design and process control.On the basis of the mathematical model research,an intelligent optimal nonlinear control strategy has been developed by combining an algorithm that regulates on-line the proportional,integral and differential coefficients by fuzzy control theory(Fuzzy-PID)and cerebella model articulation controller(CMAC)neural network for MFC,which provides an alternative to the MFC control problem for biochemical reaction process with serious nonlinearity and hysteresis in the MFC.The simulation results demonstrate that the proposed control scheme has rapider response,better control effect and stronger anti-interference ability than Fuzzy-PID controller by taking constant voltage output of MFC under the different load disturbances as example.Secondly,it is necessary to consider the design of an energy harvesting system including electrochemical capacitor,charge pump,boost converter and maximum power point tracking(MPPT)technology are the key to the development and practical application of MFC.The maximum power point tracking can maintain the maximum power output of MFC,and it is the most effective energy harvesting technology.Basedon the research of energy harvesting technology,a laboratory sediment microbial fuel cell(SMFC)is selected as the basis for the selection of mathematical model parameters.According to the characteristics of the voltage and power output of SMFC,an adaptive variable-step incremental conductance(AINC)MPPT algorithm was proposed to track the maximum power point of SMFC.The effectiveness of the algorithm in the SMFC system is verified by simulation,so it can be embedded in the MPPT energy acquisition system and other low power energy acquisition circuits.Finally,in order to simulate the natural water body structure,the sediment microbial fuel cell was used as the research object,and different concentrations of nitrate solution was used as the electron acceptor of the cathode.The effect of the external resistance and solution initial concentration on the treatment of domestic sewage by SMFC was investigated.The experimental results show that the SMFC connected with small resistance has a good decontamination effect for a higher concentration of pollution sources,which provides a theoretical basis for on-line monitoring and real-time control of the decontamination process.