Impacts of Municipal and Industrial Organic Waste Components on the Kinetics and Potentials of Biomethane Production via Anaerobic Digestion

Extensive biomass characterization, biomethane potential reactions, and kinetic modeling was performed on a variety of municipal and industrial organic wastes, including household, grocery and commercial wastes, as well as ethanol plant residues, to elucidate the effects of individual biomass components on the kinetics and total production of biomethane via mesophilic anaerobic digestion. Municipal solid waste with high cellulose (25%), lipid (10%), and starch contents (5%) achieved the highest cumulative methane production of 526 mL/g-VS, but had the longest lag phase due to the high lignin content. Vinasse residue from industrial ethanol production exhibited the lowest cumulative methane production of 302 mL/g-VS, likely due to the low cellulose (16%) and lipid contents (5%) as well as the high percentage of impurities including potassium (12%). Despite having the 3rd highest volatile solids, Vinasse had the lowest total methane production. The two feedstocks with the lowest ash contents had the highest cumulative methane productions, highlighting the potential impact of ash on methane productivity. Additionally, five kinetic models were selected and evaluated in this study based on their prior successful applications in anaerobic digestion studies. Among them, the Modified Logistic model best fit methane production from municipal solid waste with longer lag phases, while the First-order and Modified Gompertz models were more suited to industrial waste with minimal lag phases, with the Modified Gompertz model proving to be the most versatile across the five municipal and industrial organic waste feedstocks.

Graphical Abstract