Co-Digestion Canadian Style: A Full-Scale Pilot Facility at British Columbia's Largest WWTP

Metro Vancouver (Metro) is a regional government agency responsible for water, sewer, and solid waste management in the Vancouver, B.C. area. The Annacis Island Wastewater Treatment Plant (AIWWTP) processes approximately 580,000 m3/d (131 MGD) of sewage using primary sedimentation, the trickling filter/solids contact process, and anaerobic digestion and dewatering of biosolids.A co-digestion process adds digestible substrates directly into the anaerobic digesters in addition to the municipal solids processed from the liquid stream. Metro performed a market study of local industrial wastes potentially compatible with anaerobic digestion of municipal sludge in existing digesters, and identified several opportunities.A full-scale pilot facility was designed for the AIWWTP, capable of accepting, storing, and feeding substrates into existing thermophilic anaerobic digesters. Rock traps, screening, heated and mixed storage, and dual-flushing systems were provided. The facility is currently under construction, and scheduled to be completed sometime in 2011.