Anaerobic Digestion of Vegetable Waste With an Anaerobic Phased Solids Digester System

Anaerobic Phased Solids(APS) Digester system (US Patent 6342378B1) is a new anaerobic digestion technology for converting organic solid wastes into biogas for bioenergy generation. It has been studied for digesting a variety of solid wastes, including crop residues, animal wastes, food wastes and municipal solid wastes. The APS Digester system has been proven to a technical feasible and relatively simple to operate anaerobic digestion system. In this paper, research data on digestion of garlic wastes are reported. After digestion, 51% total solids and 62% volatile solids in the garlic waste were converted into biogas with a yield of 0.58 L/gVS. Based on the findings of this study and previous research, the pH value in the hydrolysis reactor should be controlled at 5.5 or above in order to ensure successful hydrolysis and acidogenesis and the pH value in the biogasification reactor is controlled at 6.8～7.8 for succesful methanogensis. Large scale APS Digester systems are being developed in the United States for waste to energy conversion.