For more than a year, North Carolina State University scientists have successfully collected hog manure and dried it to produce ethanol using an under-slat belt system in a laboratory. They have now graduated to a belt-collection system designed for an existing, partial-slat building, which is in its first trial with 120 pigs. Estimated cost of installing the system in this type of building is less than $8 per pig capacity.

Manure solids are collected on an under-slat polypropylene belt that extends the full width and length of the slatted area. The belt is operated for a few minutes every 48 to 72 hours, allowing the manure to dry to 60 percent dry matter. The dried manure is hauled to a centralized gasification facility. A ton of the dry hog feces is expected to produce 90 gallons of a product with an octane rating of 140. An 80 percent reduction in ammonia and odor is an additional bonus of the system.

The early results look promising, according to the researchers, and there appears to be future real-world application and benefits to this technology.