Caption title. At head of title: Project summary. Distributed to depository libraries in microfiche. "May 1983." "EPA-600/S2-83-024."

This study critically evaluated potential resource conservation and utilization opportunities that could be part of manure management systems and thereby reduce the pollution potential of animal manures. This work was accomplished by a detailed evaluation of literature and by laboratory studies. The following areas were investigated: (a) manures as a component of animal feeds, (b) conservation of plant nutrients in manures, (c) enhancement of manure nutritive value, and (d) energy production. When manures are considered as foodstuffs, they are best compared to corn silage and forages rather than to energy or protein feeds. Such utilization of manures is feasible only when they constitute a small fraction, less than 20%, of an animal ration. Broiler litter can be feasible at higherfractions. The amino acid content of animal manures is enhanced by short-term (less than 7-day retention time) aerobic stabilization. The essential amino acid concentration increased as much as 36% and constituted a greater percent of the total amino acids, as a result of the aerobic treatment Chemical stabilization and conservation of the ammonia in manure occurs primarily as a function of decreased pH rather than the type of chemical used. Air stripping of ammonia followed by capture in an acid solution appears to be an effective way of conserving manurial ammonia. Some form of moisture loss is a prerequisite for any thermochemical energy production process using manures. With thermochemical processes, the monetary value of plant nutrients that are lost is an opportunity cost that must be considered when energy conversion processes are evaluated. The economic feasibility of biogas production depends upon the energy source that is replaced, and the quantity of biogas that is utilized. The digester effluent does not have value as an animal feedstuff.