An offshoot of a system used to treat sewage from 12 Mexican villages is now being tested on Midwest hog confinement operations to reduce odor and eliminate the need for lagoons.
The system is called a Single Basin Extended Aeration Cyclic Reactor, known as SBEACR (pronounced su-bee-ker). AquaCare, a division of West Central Environmental Consulting of Morris, MN, bought the rights to the design in 1996 and adapted it to work for swine manure.
"We're trying to prove that large hog facilities don't have to smell," says company manager Bruce Droegemueller. He says the system virtually eliminates odor by combining a low-cost method for separating out solids with a biological process for cleaning wastewater. He claims, "One-half mile away, you are not going to know a hog farm is there, other than seeing the buildings."Turning waste into water. Waste flushed from confinement barns is separated into solids and water. After trying seven separators, AquaCare settled on a screw auger press model called Fan made in Germany.
Solids collect and compost in a bin and are later spread on cropland or processed into commercial fertilizer. Liquids are pumped into a reactor tank, where a series of biological processes turn the waste into water. Nothing is added. Instead, timed cycles of aeration and settling break down the contaminants that cause odor.
Total cycle time in the tank is four hours. For the first two hours, a 15-hp blower aerates the effluent. For the next hour effluent is left to settle. During the final hour, clean water is drawn off the top and returned to the barn for flushing or given to the animals for drinking. Effluent feeds into the reactor tank at all times to provide a steady supply of food for the microorganisms, which eat contaminants in the waste before they biodegrade into methane and other smelly gases.
"The concept is to do what we can to eliminate odor," Droegemueller says. "By separating out the solids, we've eliminated the source for generation of odor, and by treating the liquid we've put it in a state that can be returned to the barn for flushing. So it eliminates odor in the barn, too."
A secondary benefit of the technology is that it reduces the potential for pollution. "With this system, if a line breaks, you would just have clean water running into the field," Droegemueller says. And because the water is recycled instead of stored, land that would otherwise be occupied by a lagoon can be put into crop production.
Farmer-tested. With help from the Agricultural Utilization Research Institute based in Crookston, MN, the company installed a model SBEACR system on a 700-sow operation near Raymond, MN, owned by Jerome and Marcia Taatjes. Since June, it has handled all the manure from the operation, which averages 40,000 gal./ day. "It does smell better," says Jerome Taatjes, who was using a two-stage lagoon to handle waste. "And it is getting the solids, so that's impressive." But because the system has more moving parts and takes more electricity than the lagoons, the Taatjeses are waiting to see how costs compare. "I think a year from now, we'll know more," Jerome Taatjes says. "I'm optimistic."
University of Minnesota manure management specialist Jeffrey Lopez, who helped coordinate the test, says the technology shows much promise for animal agriculture in reducing noxious odor compounds.
Cost. Droegemueller says the system is ideal for farmers looking to build a new hog confinement facility or for those who want to expand.
The cost is about the same as the cost of new construction of a deep pit or lagoon. It can range from $100,000 up to $500,000, depending on the size of the hog operation and contour of the land. The one installed on Taatjes' farm cost between $150,000 and $200,000.
AquaCare is currently quoting jobs in Illinois, Iowa and Nebraska and is on the verge of signing a contract to put in a 110,000-gal./day system on a 5,200-head operation in Iowa. The company also is looking at expanding the system to dairy operations.
"You will be seeing this system on many farms in the future," Droe-gemueller says.
For more information, contact AquaCare International Inc., Dept. FIN, 14 Green River Rd., Morris, MN 56267-0593, 320/589-0090.