A 2019 law in Washington state established a goal to reduce food waste by 50% by 2030. New report assesses existing capacity for food recovery, animal feed, composting and AD.
The report categorizes anaerobic digestion as an industrial use (per the U.S. EPA food recovery hierarchy). The three main types of anaerobic digesters in Washington state are on-farm, water resource recovery facility (WRRF), and smaller, on-site digesters. (Ecology’s draft plan recommends utilization of two WRRFs in western Washington to receive food waste.) While there are five active on-farm anaerobic digesters in Washington state that process preconsumer food waste (out of nine total dairy digesters), only two were operating as of the writing of this report; the other three are undergoing facility repairs. There are also four small-scale, on-site anaerobic digesters operated by Impact Bioenergy at a brewery, cidery and farm, commercial kitchen, and tofu producer. These are permit-exempt digesters — below a threshold of 5,000 gallons or 25 cubic yards of material on-site at any one time — built to process materials generated at each site. In total, anaerobic digesters processed approximately 5,765 tons of preconsumer food waste in 2017.
On-farm anaerobic digesters generally process 50% or more animal manure and up to 30% preconsumer food waste not collected via a solid waste collection program. These digesters must submit reports to Ecology that include type and quantity of feedstocks and a digestate analysis but do not require solid waste permits. As of the writing of this report (Spring 2020), one on-farm digester was applying for a solid waste permit in order to process a higher percentage and greater diversity of food waste feedstocks.