A North Carolina study group has developed a list of value-added products that may be made from hog manure. Such activities could help offset the cost of a manure-management system and provide alternatives to direct application on land.
The researchers' report is the outgrowth of discussions by a 23-member team headed by Ellis Cowling, a distinguished professor at North Carolina State University. Over the course of 18 months, the diverse group looked at aspects of alternative technologies that might replace the lagoon-sprayfield system used presently by most of North Carolina's pork producers.
The group believes that hog manure solids, liquids and/or gases can be utilized in ways that enhance its value. They considered a wide range of end products and compiled this list of 11 categories that they believe have feasible application:
1 Energy in the form of methane, bio-gas or electricity for direct, on-farm uses.
2 Electricity for sale through a co-generation contract with a power supplier.
3 Synthetic growth media for high-value, ornamental plants or soil amendments for residential or commercial landscaping uses.
4 Nitrogen and phosphorus-rich fertilizer materials for direct application to crops such as corn, sorghum grain, cotton and more. This also is a possibility for fast-growing pine- and/or hardwood-forest plantations.
5 Fertilizer materials for greenhouse production of flowers and other ornamental plants.
6 Feed materials and nutritional supplements to enhance feed-conversion efficiency in products for fish, poultry and livestock, such as dehydrated, high-protein fish meal, amino acid and vitamin supplements.
7 Protein products for veterinary applications in aquaculture, poultry and livestock operations, including nutritional enzymes, edible vaccines and antiviral proteins such as interferon.
8 Protein products for industrial applications, including recycling, antibodies and enzymes used in detergents, plus various other uses, such as in processing pulp, paper, textiles and chemical products.
9 Products for high-value, protein-based biomaterials, including adhesives, fibers such as silk, optically active films and other biopolymers.
10 Food materials for companion animals – cats, dogs and horses.
11 High-value foods for people, including wholesome fish, vegetable, fruit and dairy products.
Of course, any animal waste used in a product for human consumption would need to be processed in a way that destroys pathogens and is fully compatible with food-safety regulations.