USDA patents method to reduce ammonia emissions

Seed Daily via SPX: Capturing and recycling ammonia from livestock waste is possible using a process developed by U.S. Department of Agriculture (USDA) researchers. This invention could help streamline on-farm nitrogen management by allowing farmers to reduce potentially harmful ammonia emissions and concentrate nitrogen in a liquid product to sell as fertilizer.

The work was conducted by Agricultural Research Service (ARS) scientists Matias Vanotti and Ariel Szogi at the agency's Coastal Plains Soil, Water and Plant Research Center in Florence, S.C. ARS is USDA's chief intramural scientific research agency, and this research supports the USDA priorities of responding to climate change and promoting international food security.

The system uses gas-permeable membranes that are similar to materials already used in waterproof outdoor gear and biomedical devices. Using these materials, the scientists recorded an average removal rate from 45 to 153 milligrams of ammonia per liter per day when manure ammonia concentrations ranged from 138 to 302 milligrams of ammonia per liter.

When manure acidity decreased, ammonia recovery increased. For instance, the scientists were able to recover around 1.2 percent of the total ammonia emissions per hour from manure at pH 8.3. But the recovery rate increased 10-fold to 13 percent per hour for manure at pH 10.0...