2010 March 16: WI: Treatment of manure (manure digester which produces methane for electricity and takes some pollutants out of area water) garnering farming industry’s attention
RON SEELY | firstname.lastname@example.org | 608-252-6131 | Posted: Tuesday, March 16, 2010 4:30 am | 1 Comment
On some farms, that’s already the case. The Dairy Business Association, which represents dairy farms and businesses, estimates that as many as 25 of the 154 industrial-scale farms in the state have installed systems to reduce manure-handling costs as well as to reduce threats to water quality.
And businesses that design such systems are betting large sums of money that some form of manure processing is going to be required as farms in the state continue to grow.
"We predicted what would happen with the consolidation of Wisconsin’s dairy industry," said Jeffrey Arnold, president of Integrated Separation Solutions, which designs manure treatment systems. "We recognized in advance that the tremendous volumes of manure were going to require special treatment."
Dane County has pioneered creation of a communal digester that will serve three farms initially. A digester – basically a large, domed steel tank – uses bacteria to turn manure into methane gas, fiber and a liquid fertilizer. The methane is used to generate electricity while the fiber can be used as bedding or sold for gardening.
The Dane County project is garnering considerable attention as a model and a possible alternative for small farms and for local governments fighting to improve water quality.
Opponents want more treatment
As the number of large farms grows, opponents are calling for more treatment of the oceans of manure they produce, which in some cases can rival the volume of waste produced by a small city. Owners of the big farms – known as Concentrated Animal Feeding Operations – are also looking for ways to cut the cost of transporting and spreading manure, reduce pollution threats and address neighbors’ concerns about odor and traffic.
Regulatory agencies have discussed requiring farms above a certain size to have treatment systems but immediate changes to the rules are not on the horizon, said Gordon Stevenson, who heads the runoff management section of the state Department of Natural Resources.
Most farmers in the state, including the very large farms, still spread their manure on fields as fertilizer. Though the manure does provide crucial nutrients and can reduce reliance on chemical fertilizers, problems such as odor, truck traffic and water pollution can arise.
A recent Wisconsin State Journal investigation found that, despite numerous instances of polluted wells and surface waters from manure running off fields, oversight of the large farms has not kept pace with their growth, with many inspected only once very five years. Smaller farms, which receive even less scrutiny from the state, can also cause pollution problems.
Still, digesters and treatment systems aren’t a cure-all, manure management experts say. Digesters, for example, can remove pathogens but not nutrients, which are the ingredients in manure that can contaminate drinking water, such as nitrates. And no farms are currently treating waste until it is pure enough to discharge back into surface waters.
The systems are also expensive, running between $4 million and $8 million, and are mostly out of reach for the small farmer unless a cooperative system such as that being built in Dane County is available.
Farmers required to follow plan
Even after partial treatment, farmers are required to spread treated manure according to a management plan. The plan is based on the levels of phosphorus, nitrogen and other nutrients in the waste and matches spreading rates to the levels of nutrients needed by crops and soil, said Andrew Craig, a nutrient management specialist for the DNR.
"You still have to carefully track what is in the manure," said Craig. "It’s like balancing a checkbook. You have to know what nutrients are going out on the field."
While digesters don’t remove nutrients, other treatment systems can begin to do that. Mike Larson, owner of Larson Acres, a large industrial-sized dairy in Rock County, is using a system marketed by Integrated Separation Solutions of Sharon, Wis., to treat manure. The system runs liquid manure through a four-step process that separates solids and liquids and reduces levels of nitrogen and phosphorus with filters.
Larson is left with a peat-like material that can be used for bedding and a liquid called tea water that he can spread on fields using an irrigation system, rather than a manure spreader and miles of pipe.
The biggest advantage, he said, is that he can better control nutrient levels so crops aren’t over-fertilized. Lower levels of nutrients also mean less threat to surface and groundwater, he added, and the treatment system also greatly reduces odor as well as the need to haul manure. Because he is better able to take advantage of nutrients in the treated manure he can also avoid using chemical fertilizers, Larson said.
A proposed expansion of Larson Acres has met with opposition because of potential water pollution threats. Dave Olsen, a supervisor with the town of Magnolia, which has challenged the expansion, said he welcomes Larson’s efforts to treat his manure and reduce levels of nutrients. But he warned that, even with the treatment, a form of the manure will still be spread on fields and testing of local waters remains crucial.
But Craig had high praise for Dane County’s community digester, which is being built for about $11 million using state and private dollars. Such an approach may be the answer for communities and small farms, he added.
For more information on Larson Acres Dairy in Rock County, go to: http://www.larsonacres.com
To learn more about manure treatment systems designed by Integrated Separation Solutions, go to: www.isepsol.com
For more background on Dane County’s community digester, go to: http://www.countyofdane.com/exec/iniatives.aspx
Posted in Environment on Tuesday, March 16, 2010 4:30 am Updated: 7:01 am. | Tags: Integrated Separation Solutions, Manure, Manure Digester, Concentrated Animal Feeding Operations, Gordon Stevenson, Andrew Craig, Mike Larson, Larson Acres, Dairy Business Association, Jeffrey Arnold