The often-criticized methane gas produced by livestock operations is being harnessed in a new process that could light homes in towns and cities.
A pilot plant in north-central Alberta is expected to draw considerable attention this summer as it begins processing solid feedlot manure into electricity.
The Integrated Manure Utilization System, or IMUS, will process manure from Highland Feeders’ 36,000 head feedlot near Vegreville, Alta., to produce power and other value-added byproducts.
Initially, the plant will extract methane from raw manure to fuel electrical generators that will produce one megawatt. That’s enough power to supply electricity to a town of more than 5,000 people.
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The dry solid byproducts of the process are useful as an environmentally friendly fertilizer, while the liquid component will be recycled as irrigation-quality water.
The project is believed to be the first co-generation plant of its kind in North America that uses solid feedlot manure to produce energy. A similar project at the Iron Creek Hutterite Colony in Viking, Alta., has been using liquid hog manure to generate power since 2002.
The IMUS technology, which has been licensed to Highmark Renewables, a subsidiary of Highland Feeders Ltd., was developed by the Alberta Research Council in a $7.9 million project funded by the federal and provincial governments as well as industry investors.
It has also been established as a demonstration project under the federal greenhouse gas mitigation program for Canadian agriculture.
“The idea is to demonstrate the technology in this feedlot scale pilot project and eventually market the technology nationally and internationally,” said Mike Kotelko, president of Highmark Renewables.
The concept is aimed at solving or reducing a number of the environmental challenges associated with handling large volumes of feedlot manure.
At the same time, products resulting from the process provide revenue to cover the capital cost of the IMUS system and for the operation.
Raw feedlot manure is a valuable nutrient source, but it produces odour, releases greenhouse gases when improperly handled, is expensive to haul and can harm ground and surface water quality. Sustainable and ecologically acceptable management of waste is therefore becoming a priority.
The IMUS project uses two 1,500 cubic metre capacity concrete tanks that serve as anaerobic digesters. The tanks, 15 m in diameter and 11.2 m high, are capped with a heavy rubberized material.
In the process, raw manure is placed in a hopper and fed into the digester tanks. Water is added to create a manure slurry.
“It is a continuous feed system,” said Xiaomei Li of the Alberta Research Council, the lead research scientist on the IMUS project. “Fresh manure can be added on a daily basis or as it is collected.”
It takes about 14 days for manure to work its way through the system.
Methane and carbon dioxide produced in the digester are drawn off and fed into a co-generation plant. The methane is used to power a reciprocal engine generating electricity for the feedlot. Surplus power will go to the Alberta power grid. Surplus gases will be eliminated through a flare stack.
Once the gas has been removed, the slurry is fed into a solid and liquid separator. The dry solids produce a nutrient-rich fertilizer. Nutrients can also be recovered from the liquid, leaving irrigation-quality water that can be reused in the IMUS process.
“The whole process provides several significant benefits for operations and the agricultural community,” said Li. “The manure is dealt with in an efficient and odourless manner, and the technology provides several value-added products.”
The pilot project is expected to be fully operational this month.
IMUS is designed as a modular system that can be expanded to meet increased manure capacity simply by adding more components. Highmark’s pilot project is geared for a 7,500 head feedlot, while a commercial IMUS system is targeted for a minimum 20,000 head-capacity feedlot. At that scale, it is estimated the system can produce 13,200 tonnes of bio-fertilizer annually with a value of $660,000 and 14,480 megawatts of electricity worth $1.01 million.
For more information on this and other environmental projects, go to the Western Producer’s website at www.producer.com and type greenhouse gases into the go box.
