Residents in the Waunakee area can provide public comment on an air pollution permit requested by Clear Horizons, operators of the Town of Vienna manure digester.
The Department of Natural Resources has scheduled a public hearing on the permit application for 3 p.m. July 9 at the Waunakee High School Commons.
Clear Horizons Dane LLC operates the digester system that processes manure from three surrounding farms to generate biogas which is then burned to generate electricity. The company is requesting to increase the hydrogen sulfide content in the biogas fired in the engines.
Clear Horizons has faced permit violations for air pollution emission and waste discharge.
The county digester was built to reduce phosphorus runoff from the farms into the Lake Mendota watershed.
The DNR has made a preliminary determination that the facility “normally does not have the potential to cause significant adverse environmental or secondary effect,” according to a public notice.
Dane County Supervisor Tim Kiefer, who represents the Waunakee area, wrote to the DNR last week to request the hearing.
Last week, the Tribune reprinted his letter. It points out that that the company “racked up almost 90 air pollution violations, specifically for burning hydrogen sulfide.”
Kiefer notes that burning hydrogen sulfide creates sulfur dioxide, which can cause acid rain.
“Clear Horizons has now applied for a new permit allowing it to burn gas containing five times as much hydrogen sulfide as is currently allowed,” Kiefer said.
Kiefer has urged the county to seek a different contractor to operate the manure digester plant.
Comments from the July 9 public hearing will be considered in making the final determination about Clear Horizon’s permit.