One of Wisconsin's biggest industries is cheese-making, and now the byproducts of that production will be used to make electricity, heat and fertilizer.
The venture, aptly called GreenWhey Energy, will turn the slurry from five cheesemakers and a soyfood ingredient plant into energy and clean water.
An anaerobic digester will process 500,000 gallons a day of milky whey - the wastewater that results from the cheesemaking process.
When the whey goes through the digester, microorganisms break it down and digest it, leaving methane gas (biogas), carbon dioxide, clean water, and a nutrient-rich solid that can be used as fertilizer.
The biogas squeezed out of the whey will generate 3.2 megawatts of electricity, piles of nutrient-rich fertilizer, heat for two area cheese factories, and water that is clean enough to drink, says GreenWhey.
The power, enough to supply about 3,000 homes, will be sold to the utility, Xcel Energy, in nearby Eau Claire.
GreenWhey's digester is about 55% complete and scheduled to be online by this summer.
The idea was born three years ago when two local dairy waste haulers became concerned about how to dispose of the growing amount of wastewater from cheese factories and other dairy producers. Rising disposal costs were a burden on the industry and tests showed traces of phosphorous runoff in streams when it was spread on fields as fertilizer. Because of that, the state stepped up regulatory efforts and it became clear another option was needed.
Faced with the option of investing in expensive water treatment facilities, more cheesemakers were cutting back.
Then they got together with a local cheesemaker and came up with the idea for GreenWhey, which could turn that liability into an asset.
"This is so much more than green electricity production," Clay Norrbo, a partner in Geo Investors Fund, told the Milwaukee Journal Sentinel. "You help Wisconsin food processors become more competitive and you use their waste to create electricity. And then the waste heat off those engines, you're able to return to a local plant that they can use for their process heat."
The biogas plant will be one of the largest privately owned wastewater treatment facility of its kind in the US - funded with senior loan financing from Caterpillar Financial Services, new markets tax credit financing from CAP Services, and additional backing from Geo Investors Fund.
The Wisconsin Economic Development Corp. is providing a $3.4 million loan from the State Energy Program - a $55 million revolving loan fund originally funded by the federal stimulus. GreenWhey will also apply for a federal grant.
In 2009 Agriculture Secretary Tom Vilsack announced an agreement with US dairy producers to cut greenhouse gas emissions 25% by 2020, by converting manure into energy through the use of anaerobic digesters.
Here is GreenWhey's website: