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Thursday, January 29, 2015 |  Madison, WI: 31.0° F  Overcast
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Dane County officials gushing over new manure digester
Going from brown to green
on (1) Comment
A rendering of the proposed facility.
A rendering of the proposed facility.

Moo-ve over, polluting energy sources of the past, there's a new powerhouse in town. Cow power.

Environmentalists and scientists have searched high (wind power) and low (hydropower) for alternative sources of energy, but in Wisconsin, the answer may be lying in the fields. That's right, in cow manure. Supporters of manure digesters have decided that going green will take a little brown, and they can't wait to get started.

Wisconsin already has 26 working manure digesters and is now poised to take a giant leap forward with a first-of-its-kind community digester in the Waunakee area that will primarily serve five farmers.

"Once this digester is up and running, we plan for it to be a model that can be replicated throughout the Midwest and hopefully the country," says Dane County executive Kathleen Falk. "The benefits of it will include sustainable energy, reduced pollution in the lakes and air, money for farms and many new jobs."

The Waunakee digester, which could be working by fall of 2010, is one of two that Dane County hopes to build; the second will likely be in located in Middleton. The digesters will convert animal waste and substrate into clean fuel and energy.

This is done by heating the manure enough to let bacteria break it down into two main byproducts - the non-digestible "leftovers," which can be used for everything from bedding for cattle to soil for potted plants; and the biogas, which can be burned to produce electricity or cleaned and used as natural gas.

In March, Gov. Jim Doyle announced that he would allocate $6.6 million in state money for the Waunakee area digester and a second digester in Middleton. This is besides the $1.2 million Falk already put into the 2009 county budget for construction. Additional federal money is being sought. The total estimated cost for the Waunakee digester: $18 million.

As of the May application deadline, the county received six digester proposals, which detail different ownership and operating models for the county to consider. County officials are now analyzing the proposals and costs before making a selection later this summer.

The electricity made from manure and food waste will help reduce dependence on coal while keeping energy dollars here in the state.

"Starting the digester market in Dane County," says Peter Taglia, staff scientist at Clean Wisconsin, "will open up even more opportunities for expanding the production of clean, local energy instead of importing dirty, out-of-state coal."

Back in 2005, after a large number of trout were killed in area lakes and streams, a Dane County task force began seeking ways to prevent animal waste from running off fields into nearby bodies of water. It landed on the idea of constructing manure digesters to process the waste.

This would allow farmers to transport their waste to digesters instead of letting it build up in fields and run into streams. These manure digesters would remove the methane, which could then be used to generate electricity. Area farmers, environmentalists, county officials and lake users saw it as a win-win-win-win scenario.

The new digester, says Falk, has four main goals: to improve water quality; help dairy farmers continue to increase their herd sizes; reduce reliance on coal and instead produce new, clean energy; and create well-paying jobs for many in the area.

"This project is exciting because it is unique," Falk says. "It is the first of its kind in that it will be used by a community of farmers, and it is the only one we know of that's taking phosphorus out of the soil, which is especially important in this area because phosphorus is a major source of pollution in our lakes."

According to Falk, constructing the digester will create up to 25 jobs for about 18 months, and more employment opportunities will come with its operation. (The costs of running the digester once built are still being negotiated between the county and participating farmers.)

Last December, Falk wrote to President Barack Obama asking him to consider including funding for "cow power" initiatives in his economic stimulus package. And in April she used her phone time with Vice President Joe Biden to invite him to see Dane's digester.

If anyone can use a good digester, it's Dane County. Altogether, dairy farms here produce a heaping total of two billion pounds of manure annually. That's a whole lot of crap that can - and does - cause a whole lot of pollution in local rivers and lakes.

Nutrients in manure, like phosphorus, can lead to the growth of toxic algae, which in recent years has been a huge problem in Lake Mendota. The county's new community manure digester is expected to take out an estimated 8,000 to 20,000 pounds of phosphorus per year from Lake Mendota. It will also save 12,000 tons of greenhouse gases each year and generate nearly $1 million dollars of electricity - enough to power 1,000 homes.

"We have a lot of animals with limited acres, meaning our farms are getting close to town [Waunakee]," says Tom Endres of the Endres Family Farm in Waunakee. "One of the biggest problems with that is keeping the phosphorus out of the lakes. This digester will remove 85% of the phosphorus from our manure."

In a typical year the farm, with its herd of 220 milking cows, produces three to four million gallons of manure. (In all, the five farms that have signed on to be involved in the community digester annually produce approximately 15 to 20 million gallons.)

There's been some concern that the digester is mainly useful to "big guy" farmers, but Endres believes smaller farmers may not need a digester because they have fewer animals per acre.

Moreover, any farm will be allowed to haul smaller loads of manure to the facility, if there is sufficient capacity at the time. The facility will be able to hold the manure of 800 to 1,000 cows, which will be especially important in late winter and early spring, when winter manure spreading and runoff present the highest risk of polluting streams and lakes.

Currently, the Endres farm has to haul manure eight to nine miles away for it to be cleaned, an expensive and time-consuming process. But once the digester is up and running, the five participating farms will be able to pump manure directly to it.

"This project will save us a little money and a lot of time," Endres says. "[It lets us] find a place and solution for the manure while cleaning the lakes."

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