State health department reviews manure sprayers
Center-pivot manure sprayers are safe for the public as long as the equipment is used at least 500 feet from a home, the manure is treated and handled properly, and the application is designed to have minimum impacts, according to a memo from the Wisconsin Department of Health Services Division of Public Health.
The Feb. 17 memo obtained by the Gazette was written to address questions raised by the Wisconsin Department of Natural Resources during that department's environmental assessment of a 5,200-cow dairy farm proposed at the intersection of Highway 14 and Scharine Road in Bradford Township.
The farm would be the largest in Rock County and the fourth-largest dairy in the state.
Nebraska dairy farmer Todd Tuls plans to break ground on the Rock Prairie Dairy next month.
Tuls plans to apply some of the waste produced by the cows through center-pivot irrigators onto growing crops. The practice is not common in Wisconsin, although it is in western states.
The proposal includes 500-foot setbacks from the applicators to inhabited homes, the memo states.
The public health risk from this method of waste application would come from bacterial or viral organisms in the waste, the emission of dangerous pollutants such as ammonia and the concentration of the waste and frequency of application, among other things, the memo states.
According to the memo, a 500-foot setback would be adequate to prevent infection if:
-- The manure storage system is treated to reduce microbes in the waste.
-- The droplets of waste are large enough to reduce drift.
-- The spraying schedule is managed with consideration of the weather and time of day.
According to the memo, if the center-pivot sprayers are approved for Rock Prairie Dairy, the state Department of Health Services recommends that the permit include the means to regulate application to assure that conditions are met to control drifting spray or odor.