Innovative Anaerobic Digestion and Co-Digestion at Inland Empire Utilities Agency

Inland Empire Utilities Agency (IEUA) has a unique advanced anaerobic digestion system at Regional Plant 1. Manure is digested at RP-1 and there are opportunities for co-digesting food wastes as well. Digester gas produces power and heat. Current plant capacity is 44 mgd ADWF, 60 mgd ADWF future. IEUA commissioned this study to compare existing Three Phase Thermophilic Digestion with other advanced digestion processes at 44 mgd and 60 mgd. IEUA also wanted to evaluate co-digesting food waste with biosolids or manure at RP-1and consider composting their biosolids at Los Angeles County Sanitation Districts'future composting plant.The study determined that the existing Three Phase Thermophilic Anaerobic Digestion provides the highest solids destruction and digester gas/energy/heat production, lowest costs, and produces Class A Biosolids. Co-digesting food waste with biosolids or manure is feasible. Composting RP-1 biosolids at the LA County Sanitation Districts' facility offers another outlet.