The Wisconsin Department of Natural Resources plans to increase the amount of air pollution allowed at the troubled Clear Horizons biodigester near Waunakee to help the facility deal with nearly 90 air emission violations the state alleged in November.
Meanwhile, the CEO of the Milwaukee-based company that owns Clear Horizons confirmed that the facility is for sale, and that a conference with state Department of Justice officials is scheduled soon to discuss a slate of alleged water pollution violations.
A public comment period ends June 15 for a new air pollution permit that would allow the manure-to-energy plant’s generators to burn gas containing five times as much hydrogen sulfide as is allowed now. Burning hydrogen sulfide releases sulfur dioxide that can impact human health and induce acid rain.
Emissions aren’t expected to reach the proposed limit, but computer analysis indicates that even if the maximum is released constantly, federal air quality standards won’t be violated, said Tom Roushar, a Fitchburg-based DNR regional supervisor for air pollution control programs.
“It slightly increased the air emissions, but it was still in compliance with the limits,” Roushar said Tuesday.
The limit set in the facility’s original 2010 permit was too low because the company didn’t fully understand the way its generators worked, Roushar said.
The plant exceeded limits for hydrogen sulfide in 43 out of 50 tests in 2013; in 17 tests, the concentration approached 38,000 parts per million, far greater than the 300 ppm concentration allowed by the permit, the DNR said.
Clear Horizons has filed reports and retrained employees to satisfy concerns that the plant was emitting excessive amounts of toxic formaldehyde and failing to meet other permit requirements including notifying the state about emissions, testing exhaust, obtaining air permits for certain equipment and supplying annual reports in 2011, 2012 and 2013, Roushar said.
The air pollution problems came on the heels of three spills of more than 400,000 gallons of dairy manure and findings that the biodigester wasn’t removing enough nutrients from manure that is spread on farm fields.
The facility was built in 2010 for $12 million, including tax subsidies, to collect gas from manure delivered by nearby dairy farms and burn it to generate electricity. The manure is supposed to be returned to the farms with a 60 percent reduction in phosphorus content. Farmers spread it on fields as fertilizer, but if it is too rich in nutrients and it runs off the fields into streams and lakes, it can result in water fouled by smelly growths of weeds and algae and pathogens that force beach closings.
Clear Horizons averaged a 63 percent reduction in phosphorus in 2011, 56 percent in 2012 and 44 percent in 2013, company reports indicate.
The DNR last year asked the state Department of Justice to take court action against Clear Horizons on the alleged water pollution violations. The state can levy fines of up to $1,000 a day for violations or close the plant.
Dane County officials have expressed frustration over problems at the digester. The county leases the land and some of the equipment to Clear Horizons and wants a new owner-operator to take over after the state violations are cleared up, said Josh Wescott, chief of staff to County Executive Joe Parisi.
Jim Ditter, CEO of Clear Horizons owner PPC Partners, said company managers who were interested in biodigesters have moved on, and he is ready to return his focus to PPC’s core business, which is electrical and mechanical contracting and service.
“If someone came along and made us an offer that was acceptable, we would certainly consider an offer,” Ditter said.
Ditter said he expects to meet in the next few weeks with state officials to discuss a possible settlement of the water pollution allegations.
The facility has three 1.25-million gallon manure tanks. On Aug. 6, an explosion and fire destroyed the roof of one of them, knocking it out of commission until about two months ago, Ditter said.
One of the other two is currently down for four to six weeks while workers clean out sand and phosphorus that has accumulated in it, creating the potential for damage to equipment, Ditter said. One of the farms that supplies manure to Clear Horizons is working on a new process designed to reduce sand in the manure, he said.