The Study On Bio-cathode MFC Treatment Of High And Medium Density Wastewater

Due to the shortage of energy and serious environmental pollution in the world,biomass power generation technology as the core of the MFC is getting more and morepeople’s attention. The properties of electricity production and decontamination makethe MFC attract many researchers’ attention.The test gives full consideration to the structure of MFC and compares theadvantages and disadvantages, then we design the two-chamber MFC which use thedomestic sewage as the electrolyte. The test is on the basis of intermittent andcontinuous flow of water, investigates the effect of substrate concentration、hydraulicretention time changes and the proton diffusion transfer between ion exchangemembrane on the MFC, analysis properties of MFC on disposing of sewage、electrogenesis combining with electrochemical and kinetics. The results show that:Organic substance concentration of the inlet has a significant saturated effect onvoltage output and power density, which can be described by the classic Monodequation, the higher concentration of the substance, the slower raise of the cell voltage.The empirical Monod equation referring to cell voltage and COD concentration of inletin the condition of continuous flow is obtained by this experiment, namelyV=132.1S/94.34+S. Compared with the batch flow, MFC operated in the condition ofcontinuous flow has a better hydraulic turbulence condition, voltage output, powerdensity and removal efficiency of COD when both of continuous flow and batch flowhave the same substance concentration. The maximum voltage output, power densityand removal efficiency of COD in the experiment are118.6mV,81.2mW/m³,80%, respectively. With the increasement of substance concentration, the efficiency of thecoulombic efficiency decreases, the maximum coulombic efficiency is1.95%and theelectron recovery efficiency is low in the experiment.With the decreasement of hydraulic retention time in the MFC, cell voltage andpower density increase slowly in the condition of continuous flow. Increasement of thehydraulic retention time is contributed to the removal efficiency of COD. The optimalhydraulic retention time in the experiment is25h, the average voltage output andpower density are112.4mV and56.2mW/m³in the optimal hydraulic retention time,respectively.Without buffer agent the MFC anode and cathode pH as continuous flow of wateris better than the intermittent, anodic electrolyte pH is close to neutral; compared withother researchers’ conclusion, MFC anode pH is not significant decline, the reason isthat Gore-Tex’s mass transfer ability of OH^－is stronger than H⁺, a large number ofOH^－expanding from the cathode to the anode, acidic environment of anode isneutralized. Mass transfer coefficient of OH^－is KT=1.402×10^-6cm·s^-1.