Anaerobic co-digestion of agricultural products and industrial wastes

The directives from the European Union require member states to increase a renewable energy consumption and to reduce uncontrolled methane emissions. The main objective of the present investigations was to optimize the substrate combinations and the process conditions for maximum productivity of methane-rich biogas. The paper presents the result of co-fermentation of corn silage and whey together with glycerin fraction, the waste product of transestrification of oils (biodiesel production), in 25-dm3 bioreactor operating mesophically in semi-continuous mode. This allowed us to obtain a high productivity of methane-rich biogas, reaching 1.82 dm3/dm 3/day with methane content being 60-62%, the biogas yield of 2.04 dm3/g TS removed and 32% COD reduction.