Fuel gases from organic wastes using membrane bioreactors Original Research Article

One way to produce fuel gases is using bioreactors producing CH4/CO2, H2/CO2 and CH4/H2/CO2 gas mixtures. This method has many advantages; for example, low energy consumption, high ecological efficiency, utilization of organic wastes, accessibility and simplicity of hardware implementation. The results of organic waste bioconversion into methane and hydrogen by using an active membrane system integrated with aerobic and anaerobic bioreactors are presented. The suggested biomembrane system includes three types of fermenters: an aerobic phototrophic biomass producing reactor for CO2 consumption and O2 production from Anabaena variabilis, an anaerobic methane bioreactor for biomass transformation into biogas by using the methanogenic community, and Rhodobacter capsulatus immobilized in a polymeric matrix. The latter system was used for lactate or other low organics decomposition. The combination of the biosystem with membrane contactors and a selective membrane valve achieves a continuous process for energy production and total removal of CO2 from microbial gas mixtures, which can be fed back into the first aerobic productive reactor. In total, the developed system obtains energy from sunlight in the form of combustive gases (CH4 and H2) with a net CO2 consumption.