Co-digestion at Annacis Island WWTP: Metro Vancouver's Path to Renewable Energy and Greenhouse Gas Emissions Reductions

Annacis Island Wastewater Treatment Plant which is operated by Metro Vancouver, is leading the way in working within a carbon based regulatory environment. British Columbia has instituted carbon reduction legislation province wide, a leader in North America. As a result public entities, such as Metro Vancouver, must be carbon neutral by 2012. In response the utility is holistically investigating different approaches to achieve the required GHG reductions. One approach now being actively pursued is the implementation of co-digestion at Annacis Island. Having developed a the scope for a full co-digestion program at the plant, a pilot facility was constructed to provide further process controls as well as a start at reducing emissions by codigesting material at the plant. This project also provided Metro Vancouver a basis of handling its own sludges from other wastewater treatment plants on an emergency or planned basis by dual tasking the receiving facility to receive both sludges and co-digestion substrates.