West River open house to showcase digester
It's hard to mistake Riverview's primary business function considering that thousands of cows are milked daily at its dairies.
But Riverview takes pride in having diversified its operations. So much so that the phrase "Producing More Than Milk" is part of one of its company logos.
To celebrate Dairy Month in June, Riverview is preparing for an open house at its West River Dairy from 3 p.m. to 7 p.m. on June 24, on County Road 8 south of Morris.
In addition to a free meal of cheeseburgers, beans, chips and malts, West River will conduct tours of its dairy and its digestion facility, which turns the dairy's abundant supply of manure into electricity.
West River currently operates digesters in two of its dairies and a third will be installed and operational this fall, said West River's Kevin Wulf.
"We're not only gaining the green electrical piece," said Kevin Wulf, of Riverview, "but we're taking something that has value and using it efficiently."
"We're going to have manure anyway," said Jim Nieland, who handles Riverview's digester operations. "We might as well benefit from it."
Riverview installed its first digesters at the end of 2008 at its Riverview and West River dairies. The District 45 dairy digestion system will be completed this fall.
The manure from the dairies' "day pits" is moved into the digester, which is a 150-foot by 300-foot concrete tank that is about 16 feet deep. The tank can hold about 3-1/2 million gallons, Nieland said.
About 14 feet of the tank is manure and it is "digested" at 100 degrees for 21 days. Methane gas rises to the top two feet of the tank during the process and is drawn into the digester building. It's chilled to remove moisture and then the gas is burned to run turbines that produce the electricity.
The digestion process produces electricity equivalent to that needed for 1,200 homes. The power is fed to a substation and to a power company grid.
And, in keeping with "Producing More Than Milk," the manure is eventually emptied and separated into fiber and liquids. The digestion process makes the solids, which are reused as cow bedding, cleaner. Somatic cell counts are lower when post-digestion bedding is used, Nieland said.
The liquid are pumped to ponds and eventually used as fertilizer.
The technology is changing quickly. The digester system being installed at the District 45 dairy is a little more advanced than the other two, despite being only two years newer, Nieland said.
"The last few years have brought about growth in the industry," he said. "Just five years ago, there was a lot less known about it. Vendors keep coming up with better ways of doing this."
The diversity digestion offers helps the business, too, Wulf said.
In 2009, when milk prices fell significantly, the electricity and fertilizer production served as a buffer, he said.
"This extra income helped pull that bottom line up," Wulf said.