Multiple Substrates Anaerobic Co-Digestion: A Farm-Scale Biogas Project and the GHG Emission Reduction Assessment

UGlobal warming has become an increasingly inconvenient situation, indicating the importance of reducing greenhouse gas (GHG) emissions. Anaerobic co-digestion of multiple substrates is an effective way to utilize wastes and reduce GHG emissions. In this study, batch anaerobic co-digestion of pig manure, corn straw, and fruit and vegetable wastes (FVW) was performed in a laboratory and extended to a farm-scale biogas project. Laboratory test results showed a specific biogas yield of 420.18 mL/g VS when the ratio of pig manure, corn straw, and FVW was 100:20:1 (TS). A farm-scale biogas project was improved on the basis of laboratory studies, and an average specific volumetric biogas production rate of 1.22 m 3 /m 3 d was obtained. For GHG emission reduction assessment, the open anaerobic pond of pig manure, solid waste disposal site of FVW, and uncontrolled burning of corn straw were used as baselines, obtaining a total GHG emission reduction of 303.08 t CO 2 annually. The farm-scale biogas project could treat corn straw, pig manure, and fruits and vegetable wastes, achieving considerable environmental benefits. Graphic Abstract