USDA converts manure to energy

By Ryan C. Christiansen
Web exclusive posted Oct. 3, 2008 at 10:10 a.m. CST

Researchers at the USDA Agricultural Research Service Coastal Plains Soil, Water and Plant Research Center in Florence, S.C., are studying various ways to convert livestock manure into energy. Using wet gasification and pyrolysis, the scientists are converting manure into synthesis gas, liquid fuels, and charcoal.

According to the USDA, there are more than 96.7 million cattle and 67.7 million hogs and pigs in the United States, the USDA said.

Wet gasification can be used to convert wet livestock manure slurry into syngas and pseudo-clean water. The U.S. DOE Pacific Northwest National Laboratory is developing a catalyst for the technology, the USDA said. Under processing conditions of 662 degrees Fahrenheit, wet gasification destroys pathogens, odor-generating organic compounds, and also hormones in as little as 15 minutes, which is exponentially quicker than the days and months required to process manure using anaerobic digestion, the USDA said. The scientists are also working with the Advanced Fuels Group at the DOE Brookhaven National Laboratory in New York to develop catalysts for converting syngas into liquid fuels.

According to the USDA, in addition to syngas and liquid fuels, ARS researchers are developing methods for using pyrolysis to convert manure into biochar, a type of charcoal dubbed green coal. Green coal can be burned to produce energy or transformed into activated charcoal that can be applied to soils to improve soil quality and to sequester carbon.