Feedlot Wastes to Useful Energy—Fact or Fiction?

Abstract

The large quantities of wastes generated in commercial feedlots have been receiving attention as to their possible energy value. Research has indicated however that on the typical open lot much of the potential energy source is reduced by the natural degradation of the organic matter during the up to 150 days that the material may remain on the lot. Anaerobic digestion was studied as the system for energy recovery. Three case studies for a 35,000-head feedlot were looked at: a dirt lot, a concrete lot, and a total confinement system with fresh manure removal. Anaerobic digestion of dirt lot waste will produce no net gas. Anaerobic digestion of freshly collected wastes may produce excess gas at a cost nearly that of existing natural gas prices. Even at this price it must be approached with caution since other considerations such as cost and energy requirements of confined feeding and sludge disposal must still be considered for each installation.