Dry anaerobic co-digestion of organic fraction of municipal waste with paperboard mill sludge and gelatin solid waste for enhancement of hydrogen production

The aim of this study is to investigate the bio-H₂ production via dry anaerobic co-fermentation of organic fraction of municipal solid waste (OFMSW) with protein and calcium-rich substrates such as gelatin solid waste (GSW) and paperboard mill sludge (PMS). Co-fermentation of OFMSW/GSW/PMS significantly enhanced the H₂ production (HP) and H₂ yield (HY). The maximum HP of 1082.5±91.4mL and HY of 144.9±9.8mL/gVS_removed were achieved at a volumetric ratio of 70% OFMSW:20% GSW:10% PMS. COD, carbohydrate, protein and lipids conversion efficiencies were 60.9±4.4%, 71.4±3.5%, 22.6±2.3% and 20.5±1.8% respectively. Co-fermentation process reduced the particle size distribution which is favorably utilized by hydrogen producing bacteria. The mean particle size diameters for feedstock and the digestate were 939.3 and 115.2μm, respectively with reduction value of 8.15-fold in the mixtures. The volumetric H₂ production increased from 4.5±0.3 to 7.2±0.6LH2/Lsubstrate at increasing Ca⁺² concentrations from 1.8±0.1 to 6.3±0.5g/L respectively.