MICROBIALLY-ASSISTED WATER ELECTROLYSIS FOR IMPROVING BIOMETHANE PRODUCTION

摘要

A method of producing in a bioreactor a biogas rich in methane involves electrolyzing water in an aqueous medium at a voltage in a range of from 1.8 V to 12 V in the presence of electrochemically active anaerobic microorganisms that biocatalyze production of hydrogen gas, and, contacting a species of hydrogenotrophic methanogenic microorganisms with the hydrogen gas and carbon dioxide to produce methane. Volumetric power consumption is in a range of from 0.03 Wh/LR to 0.3 Wh/LR. Current density is 0.01 A/cmE2 or lower. The voltage is sufficient to electrolyze water without destroying microbial growth. Such a method results in improved electrolysis efficiency while avoiding the use of noble metal catalysts. Further, a combination of water electrolysis with anaerobic degradation of organic matter results in increased biogas quality and in increased biogas quantity and yield. Oxidation of hydrogen sulfide contributes to the increased quality, while an increase in the rate of organic matter hydrolysis and an increase in the production of methane from hydrogen contributes to the increased quantity and yield.