The den Dulk dairy farm is building a new "biodigester" that will convert cow manure into methane that will be used to power electrical turbines on the farm and be sold back to the power company.
The Ravenna farm is investing $1.2 million in the project to go along with a $1 million Michigan Public Service Commission investment. Grand Valley State University and its
Michigan Alternative and Renewable Energy Center is a partner in the project won the grant and is coordinating the project.
"You are tapping into an ever renewing energy stream and because it is waste, we have to deal with it anyway" said Sarah Lineberry, the GVSU project coordinator for the biodigester.
There are fewer than 500 similar biodigesters in the United States and only a handful in Michigan. The state lacks incentives to build the devices that other states, like California and Wisconsin, have.
A giant mixer in the tank helps breaks down the waste with the aid of microbes. The manure from the cows will be will be kept in the digester tank for an average of 21 days at about 98.6 degrees. The result is biogas, which is comprised of 60 percent methane. Hydrogen sulfide will be removed to eliminate its smell before transferred to a holding tank. Then it will be available to be used in microturbines on the farm or boilers to create electricity and heat.
The other product of the process is a material called "digestate," which is nutrient-rich and can be used as a fertilizer. That product has a 95 percent reduction of odor and a 99 percent reduction of pathogens compared to unprocessed manure.
"Removing the odor is a big issue for these farmers," said Lineberry, who pointed out that livestock farmers have to monitor odor plumes eminating from their farms.
Construction should start in early spring.
Source: Sarah Lineberry, Grand Valley State University
Photo of a biodigester in Kogel, Germany - courtesy of Sarah Lineberry/GVSU
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