Manure testing begins

MARIA STEIN - Ag officials hope results from manure settling tank tests prove it's economically feasible to transport liquid hog waste out of the Grand Lake Watershed.

Three, 250-gallon tanks containing liquid hog manure were set up a few weeks ago at the Ted Heitkamp farm north of Maria Stein. Terry Mescher, an agricultural engineer with the state, is conducting the experiment and hopes to repeat it at two other farms, after the bugs are worked out.

"What we're trying to establish is can we develop a sludge on the bottom that will be more economical to export out of the watershed," Mescher said.

The Canadian designed process allows nutrient-rich solids in manure to sink to the bottom, with the liquid staying on top. A $4,500 state grant is being used to run the tests.

Hog manure, which is 95 percent water, is messy and costly to transport due to weight. If officials can reduce the water and increase the nutrient concentration of the solids, then it becomes economically feasible, Mescher said.

"Ultimately ... it would be about trying to provide a cheaper alternative to commercial fertilizer," Mescher said. "As the price of commercial fertilizer goes up, the economics of hauling and exporting manure becomes more and more inviting."

Phosphorous, a main nutrient in manure, is useful as fertilizer but damages water quality when it gets in waterways. Grand Lake has been suffering from toxic, blue-green algae blooms, which are fed by phosphorous, for several years. Most of the phosphorous runs off farmland, the main land use in the 58,000-acre watershed.

Watershed farmers are being compelled by new state rules to reduce runoff by following nutrient management plans that in some cases restrict manure application and require conservation practices and added manure storage. The rules resulted after the state designating the Grand Lake Watershed distressed after humans and animals became ill from the lake toxins in 2010.

If the settling tank process works, farmers could use the technology to comply with the news rules, Mescher said.

"This can help them," Mescher said. "Once we verify we can do the settling, we still have to develop the procedures and how it's going to get done."

Mescher said he hopes to be able to use the settling process on a farm in the watershed in the next year to 18 months.

The three tanks at the Heitkamp farm were filled with liquid hog manure from the farm on Aug. 31. Manure samples taken seven days later showed 50 to 60 percent of the phosphorous had dropped out of the top liquid into the bottom sludge. The second sample taken seven days later showed a slight increase in settling but nothing significant.

The final samples will be taken Friday and then the tanks will be drained. The bottom sludge will be sampled to determine the phosphorous concentrations.

Mescher said he's aiming for at least a 75 percent reduction in phosphorous from the top liquid.

"If we can get that consistently, I'm thinking it will be something viable," Mescher said. "If it is less than that, or we can't do it consistently, the economics will be tougher to make it work."

The top liquid possibly could be used to irrigate crops if its phosphorous level is low enough, he said.

Heitkamp said he would consider using the system on his farm if it's viable. He now is in the process of signing agreements to have some of his swine manure taken off his farm and outside the watershed.

He said it's important for lake watershed farmers to try new technologies that address phosphorous runoff.

"With the new regulations, we've got to watch what we are able to do," he said.