Effects Of Key Control Parameters On Electrochemical Anaerobic Digestion

The non-renewable fossil fuels and the increasing global energy demand have made the main crisis that society urgently needs to overcome in the current energy crisis.The development and utilization of biomass energy has also become a top priority for development.As a renewable and clean energy,biomass energy is inexhaustible,but the existing development and utilization methods have disadvantages.Electrochemical anaerobic digestion(EAD),as a new technical method of using biomass to produce clean energy methane,provides a new solution for the utilization of biomass and the resource utilization of domestic waste and domestic waste.The most important structural unit in the EAD reactor is a microbial electrolysis cell unit.In the microbial electrolysis cell unit,electro active microorganisms grow and accumulate on the surface of the anode,and at the same time decompose oxidized organic matter to form an electron flow,which in turn generates hydrogen and releases it into the reaction system.Hydrogen tropic methane bacteria reduce carbon dioxide to produce methane,so the electrochemical anaerobic digestion technology can effectively increase the methane content of biomass gas while reducing the carbon dioxide content.The experimental results show that compared with the traditional anaerobic digestion technology,the average daily gas production of electrochemical anaerobic digestion has increased by 20%,the average methane content has increased by 50%,the average carbon dioxide content has been reduced by 60%,and the substrate digestibility has also increased from 50% to 75%,it can effectively improve the substrate utilization rate and then increase the methane yield to produce bio-natural gas.The applied voltage and external load have a significant effect on the performance of electrochemical anaerobic digestion.The increase of the external voltage is conducive to the growth of electro active microorganisms in the EAD system to promote the generation of current.At 4.0 V,the EAD produces the highest current,the electro active microorganisms have the strongest activity and the best methane yield.At 6.0 V,the current generated by EAD began to decrease,the electro active microbial activity of the reaction system and the digestibility of the substrate began to decrease,and the methane yield also decreased.The EAD that reduces the external load operation produces a stable current and a higher methane yield.To a certain extent,reducing the external load can promote the electrical activity of the bioelectrochemical unit in the system,and the methane yield of the reaction system changes under a fixed anode volume.The retention time of water conservancy and the concentration of substrate = the main fermentation parameters affecting electrochemical anaerobic digestion.Prolonging the water retention time can reduce the organic load per unit time of the reactor,and then promote the full oxidative decomposition of the substrate in the reaction system.At the same time,it can increase the activity of electro active microorganisms,help the electrochemical unit to generate current,and thus increase the methane yield.The increase in substrate concentration is not conducive to the formation of the current of the electrochemical cell.When the current increases from 15 gL to 25 g / L,the current generated in the system decreases from 20 mA to 17.2mA,and the methane yield and methane content decrease simultaneously.