Dairy cows' manure being turned into energy, money

Sunnyside's Noon Rotary Club guest speaker, Dan DeRuyter, spoke Monday about the progress being made on his dairy's manure digester.

The DeRuyter Dairy near Outlook has been in operation since 1972 and after DeRuyter graduated from Gonzaga University, he joined his father George in the family operated business.

"Manure digesters have been around for more than 20 years. But, it was about 10 years ago that my dad expressed an interest in them. About three years ago we found out they might be a viable venture," DeRuyter said. "We traveled to Wisconsin to learn more and decided to try it."

The manure digester is a concrete tank, which is built in an "S" configuration. "The inside looks like a radiator," he explained.

The coils inside the digester are heated to 101 degrees, where the enzymes are most active and will eat the manure to release methane gases. The methane gases are captured and pumped to two 900 horsepower engines. The engines have the capacity of generating 1,200 kilowatts of electricity per hour and are currently operating at approximately 900 kilowatts per hour. "It has been an up and down experience due to weather conditions. The most difficult part of the process has been in getting the digester to 100 degrees to begin with. The cold weather hampered that, and now we are able to sustain the temperatures needed," DeRuyter said.

The digester also produces a fiber product. "This product is much like peat moss. We are calling it 'Enviro Moss.' It is a bagged product and it's 20 percent more absorbent than peat moss," he stated.

"Another good thing about the product is that it's renewable. There are more nutrients in it and it is a U.S. product, whereas peat moss is a product from Canada," he said.

Another byproduct of manure that results from the digester is manure water. "Usually it takes four years for the water to break down and become a viable product. With the digester, it can be used immediately on crops and fields," DeRuyter explained. "It is a concentrated product."

The waste heat from the digester is being pumped in to heat the barns on the DeRuyter Dairy and the dairy now receives "Carbon Credits" for being ecologically-minded. DeRuyter explained the carbon credit program pays entities that conserve and reduce methane or carbon dioxide gases released into the atmosphere. "It is a part of the Kyoto global warming treaty," he stated.

The benefits aren't only to the dairy, but to its neighbors. "We have better neighbor relations. There has been a significant reduction in the smell from the dairy."

Currently, the fiber product is in the process of being readied for sale. "The rain has hampered us. The extreme moisture absorbency has had the moss too wet when it needs to be at 30 percent moisture. But, we are figuring out a way to overcome that," said DeRuyter.

The digester has allowed the dairy to use close to 100 percent of its dairy manure. "It has been a good way to be paid to remove manure, rather than pay out," he stated.


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