Co-digestion of fat, oil, grease (FOG) with municipal wastewater sludge for enhanced biogas production in Okanagan Valley

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In recent years, fat, oil and grease (FOG) discharged from restaurants, commercial kitchens and food serviceproviders has become a major organic waste stream in the Okanagan. Historically, the primary method fordisposal of FOG collected from grease traps installed at the point of generation was to discharge directly intothe municipal wastewater treatment plants (WWTPs) or at landfills, however many waste treatment utilities aremoving forward with restricting FOG disposal due to negative impacts on operations (e.g. pipe/manholeblockages causing overflows). In some municipalities in the Okanagan, disposal options will soon be limited tohiring a certified waste hauler from the Metro Vancouver area to collect waste for transport to Vancouver foranaerobic co-digestion at Annacis Island WWTP. This will increase GHG emissions and impacts on roadinfrastructure for transport (around 800 km round trip). Anaerobic digester is a heated/mixed bioreactor whereorganic waste (substrate) is converted to renewable energy in the form of biogas.The main objective of this experimental research is to investigate the effect of FOG as a co-substrate invarious configurations of bench-scale anaerobic digesters utilizing wastewater sludge from WWTPs in theregion. The local wastewater utilities have been considering anaerobic digestion (as an alternative to currentcomposting process) for biogas generation and improved quality of biosolids for land application as fertilizer. Itis expected that addition of FOG to wastewater treatment sludge would boost biogas production and increasecost efficiency. If laboratory scale results indicate a significant advantage over the current sludgetreatment/disposal scenario, the utilities will have the option to incorporate the use of FOG as a co-substrate inanaerobic digestion and will benefit from an increased biogas production allowing the use of a co-generationengine to significantly offset the WWTP's energy use. The project will also provide an environmentallysustainable method for FOG disposal and will train highly qualified personal in an important/desired field.