Hog Farm Comes Out Smelling Like A Rose

Last July, the EnviroPork hog farrowing facility west of Larimore, N.D., faced possible penalties for violating state odor regulations and a potential shutdown because of a lawsuit filed by two local residents. Today, using EERC expertise in odor control technology, the area around the operation is nearly odor free. Potential impacts on groundwater are being carefully monitored by EERC researchers.

The EnviroPork facility, leased by the North Dakota Pigs Cooperative (NDPC), holds 5,000 sows and produces more than 100,000 piglets a year. It began operating in December 1997. Early this year, the facility was criticized by North Dakota Department of Health and later by some area residents. Odor readings recorded on several occasions were out of compliance with state regulations. Another concern was that EnviroPork's manure lagoon could contaminate an important regional groundwater source.

Last spring, the Health Department requested improvements at the hog farm to address odor and other problems. EnviroPork took steps to remedy the odor issue through feed additives and enzymes placed in the manure lagoon. However, this did not completely resolve the odor issues. The Health Department then recommended that EnviroPork contact the EERC for assistance.

"We interviewed several different organizations for this project," says Amon Baer, NDPC president. "Once we saw the level of expertise that the EERC had to offer, we realized that it was in the best position to assist us."

The cooperative joined the Red River Water Management Consortium, an organization formed by the EERC two years ago to develop technical solutions for industry, municipalities and other organizations concerned with water management issues in the Red River Valley.

Before the end of July, the Health Department approved a plan drafted by the EERC to address EnviroPork's odor problem and the groundwater issue. By early August, EERC scientists and engineers were on site at EnviroPork, supervising odor control efforts and the drilling of additional wells to monitor groundwater quality and provide additional information on local geology.

The solution to EnviroPork's manure lagoon odor problem was low-cost, low-tech barley straw. Using a straw cannon that pulls apart bales and shoots the straw up to 150 feet, barley straw was spread over the two-acre manure lagoon to form an eight- to 12-inch-thick matt covering.

Dan Stepan, an EERC research manager, says that the straw acts as a biofilter by providing a favorable environment for the growth of microorganisms. These microorganisms use the odor-causing compounds as a food source, breaking them down to odorless carbon dioxide and water.

"Barley straw works best because it floats well," says Tom Moe, an EERC research engineer. "The straw has a waxy coating that prevents it from becoming quickly saturated with water."

Last year, results from a barley straw demonstration at the American Crystal Sugar Co. (ACS) beet-processing plant in East Grand Forks, Minn., were so encouraging that the company is now using the technique at its plants in East Grand Forks, Crookston, Minn., and Moorhead, Minn. The idea originated at the Prairie Agriculture Machinery Institute (PAMI) in Portage La Prairie, Manitoba, Canada.

Another source of odor was EnviroPork's hog barns. During warm weather, large fans are used to ventilate the barns for temperature control. The air coming out of the barns contains small particles of pig dander, feed dust, manure and other compounds that contribute to odor problems. The EERC designed a unique filter system consisting of vertical walls of barley straw. Air coming out of the barns is blown into the straw walls, capturing particles and removing a significant source of odor.

Since the barley straw was applied on EnviroPork's manure lagoon and filter walls were constructed near the hog barns, the results of odor inspections at the facility have dramatically improved.

"I've been extremely impressed with the low odor level around the facility," Baer says. "I'm absolutely amazed that a design this simple is having such a dramatic effect. It's the best money our cooperative has spent."

Francis Schwindt, chief of the state Health Department's Environmental Health Section, says, "We're pleased that the co-op brought in knowledgeable consultants who were able to bring the facility into compliance. The technology employed at EnviroPork indicates that hog facilities can be constructed, operated and maintained to meet state odor standards."

EERC research at EnviroPork has also helped alleviate groundwater concerns. David Rush, a hydrogeologist and EERC research associate, says that based on the results of wells drilled at the site, "We are currently unaware of any underground formation or path for groundwater to follow that would enable seepage from the lagoon to contaminate the nearby Elk Valley Aquifer." The aquifer is a major source of water in the region for domestic and agricultural use.

There are now seven wells at the EnviroPork site to monitor groundwater quality. Rush says this is an unusually large, but necessary, number of wells for such a facility. The State Health Department's recommendation for additional wells was based on the site's characteristics, rather than a general design specification.

EERC Director Gerald Groenewold calls the EnviroPork experience a success story, one that could be repeated wherever agricultural facilities exist or are being considered. "The Red River Water Management Consortium was created to deal with situations like this," he says. "We've demonstrated the value of having a basinwide water management organization made up of government and industrial entities that can call on the scientific and technical expertise of a research center such as the EERC. It's a unique model that could be applied anywhere in the world."

During 1998, the Red River Water Management Consortium received $280,000 in funding from the United States Department of Agriculture for a variety of projects addressing technical issues related to the development of a water management strategy for the Red River Basin. Stakeholders in the consortium are providing an additional $90,000 in funding.