Tuesday, January 23, 2018

Edmonton’s Anaerobic Digestion Facility by MCR Tim M.

It Will Take Your Breath Away

A collaboration between the City of Edmonton and the University of Alberta, the Anaerobic Digestion Facility (ADF) will process up to 48,000 tonnes of organic waste when in operation, producing electricity, heat and compost. In anaerobic digestion, material is broken down in the absence of oxygen. This results in the production of biogas (largely methane), which can be used to power electrical generators. Although more common in Europe, this type of facility is only the second if its kind in Canada (the other one is in Richmond, B.C.).

When operating, organic material is placed into one of eight long, 5m x 35m cells and inoculated with water that contains the necessary microbes for the digestion process. Over 28 days, the material breaks down and produces biogas, which is then sent to two 800 kW generators.

A view from inside one of the cells. It takes about eight hours to fill a single cell with organic waste.

The generators produce heat and electricity. The heat, about 90⁰C, will be used to dry the garbage fluff in the Integrated Processing and Transfer Facility(IPTF), which is then used as feedstock for Enerkem’s Waste-to-BiofuelsFacility. After losing some of its heat to the drying process, the air returns to the ADF at around 60⁰C -- the temperature ideal for anaerobic digestion -- and helps to heat the digestor cells.

Once the anaerobic digestion process is complete, the remaining material is moved into an aeration bay and mixed with carbon-rich green wood and further composted in an oxygen-rich environment over a period of 10 to 12 days.

Set to open in 2018, the Anaerobic Digester was built primarily to compost unmixed, organic material such as household food and yard waste. The electricity will be used to power the Edmonton Composting Facility (ECF). Waste Services will consider how to use this electricity when the ECF is not operating, depending on need.

Learn about the Edmonton Waste Management Centre.
Visit edmonton.ca/ewmc
Visit EWMC Interactive Site Map

Tim is an employee with Waste Services who completed the MCR Training in 2017. As a member of the Education Team, he leads tours of the Edmonton Waste Management Cenre and involves Grade Four students in managing their own waste.

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