Manure: dirty, smelly, polluting nuisance. Right? Wrong! Manure, in fact, has played a significant role in sustaining life for centuries. First Nations peoples and, later, settlers utilized dried buffalo dung (a.k.a. meadow muffins) as a source of fuel for cooking and heating due to the scarcity of trees on the Canadian prairies.
Today, manure is widely employed as a fertilizer by farmers and gardeners worldwide. Unfortunately, due to increased herd sizes resulting from modern intensive livestock production methods, the supply of manure is rapidly outpacing demand. An excess of animal waste poses a significant threat to the long-term environmental sustainability of animal agriculture in Alberta, primarily in the form of surface and groundwater contamination .
This threat can be addressed through a synthesis of traditional practices and modern technology; a biodigester is a perfect example of such a synthesis. In a biodigester, manure is broken down by anaerobic digestion which causes a combination of gases, known as biogas, to be produced. This biogas can then be used as a source of fuel, to produce both heat and electricity. In addition, the material that remains following digestion can be used as fertilizer. Just as meadow muffins were a source of renewable energy for settlers and First Nations peoples, animal waste produced in intensive operations like
The opportunities for manure as energy feedlots can provide the fuel for a modern method of sustainable energy production, and on a much larger scale. However, this technology has been slow to catch on. Investors have been reluctant to get onboard, despite a 2006 9-Point Bioenergy funding plan passed by the Alberta government to encourage sustainable energy development . According to Mike Kotelko (VP Highland Feeders), sophisticated technology and expertise is required in the construction of biodigesters and, therefore, initial capital and subsequent operating costs can be prohibitively high.
Kotelko maintains that in order for biodigesters to be economically viable they must be of a sufficiently large scale to offset operating costs and, in addition, they should be integrated on-site with complementary processes (such as ethanol production) that allow the byproducts of one process to be used in the other. Highland Feeders successfully operates an integrated biodigester, providing proof that this technology is economically feasible.
Biodigesters, then, represent a sustainable solution to two problems: finding a source of environmentally friendly, renewable energy, and what to do with all that poo!
– Christa Hostettler, Mark Smith, Jenn Stellbrink, Jacob Boychuck, Jordan BUrke, Rachel Myers and Erika Strande