Hydrothermal Carbonization of Cow Manure

Traditional methods of cow manure use are problematic for many large dairies. Mismanagement can cause nutrient runoff and environmental pollution of water, air, and soil. At the same time, modern dairies utilize great amounts of heat and electricity for operation. While dried manure has significant value, the high moisture content of fresh manure (~85%) makes it impractical for direct burning.  We have been exploring application of hydrothermal carbonization (HTC) to manure for production of solid carbonaceous fuel we call “bio-carbon”, which is amenable to storage and gasification for distributed power generation. Results of batch experiments indicate that the fuel value of manure is readily concentrated in the bio-carbon, while the aqueous products include organic acids, sugar derivatives, and nutrients. Future efforts include upgrading HTC liquid products to fertilizer and platform chemicals, and gasification of the bio-carbon for power generation.