The Georgia poultry industry has experienced steady growth over the past decade, growth that has helped create new wealth and employment opportunities for the state. At the same time, this growth has also created new challenges for the industry relative to resource utilization and waste management.

One challenge that has drawn national attention in recent years throughout the poultry industry has been the management and use of poultry litter and manure on poultry farms. While poultry farmers have always valued this material for its nutrient-rich, soil-enhancing qualities, there have been growing concerns that some farmers may be overapplying the material to their fields with a resulting negative impact on the surrounding environment.

A biomass gasifier system similar to this unit in Stuttgart, Ark., is capable of processing 150 tons of litter a day and producing 4 megawatts of electricity.

In response to this concern, the Georgia poultry industry implemented a voluntary nutrient management program to help ensure that poultry farmers effectively match the nutrient content of their litter and manure to the nutrient needs of their fields. Effective broiler litter application improves soil fertility because it contains many beneficial plant nutrients, e.g., nitrogen (N), phosphorus (P), and potassium (K).

Broiler litter helps increase the organic matter content of soils, thereby increasing soil water-holding ability and improving soil aeration, structure, and microorganisms. Broiler litter also contains both organic and inorganic constituents that may provide useful energy or other derived benefits.

In instances where farmers have more litter than they can responsibly apply, the Georgia Poultry Federation has set up a manure-matching service to help the farmers find suitable outlets for excess litter.

Granulation systems used in conjunction with gasification systems can turn the ash from poultry litter into packageable, exportable, granulated fertilizer. Photograph provided by Primenergy, L.L.C., Tulsa, Okla. All rights reserved.

This service thus far has identified more demand for than supply of excess litter.

Despite these measures, however, the industry is also committed to exploring future ways of using poultry litter and manure for potentially new, value-added products. In other regions of the country where this challenge has been more acute, alternatives such as burning litter to generate electric power for use by the industry or for sale on the power grid, and extrusion of poultry litter into pellets for transport to other parts of the country in need of its soil-enhancing abilities are currently being evaluated. While Georgia continues to be fortunate with regard to its waste management situation, it has also initiated a strategic look into alternative waste management schemes.

This study, headed by researchers at Georgia Tech, is investigating the economic feasibility of power-generating schemes and fertilizer-production options. In addition, the researchers are exploring novel options such as using litter as an ingredient for man-made building materials.

In investigating the power-generating schemes, the team is exploring both large-scale (40 megawatts) and medium-scale (4 megawatts) power-generating systems. Building on technology already developed for this purpose (see photo on page 1), researchers are considering cost issues such as the overall cost of construction, the value of electricity produced either in displacing purchased power or selling to the grid, the cost of acquiring and transporting litter from farms, and the value of ash and steam byproducts.

As for fertilizer-production and novel use options, the study team is considering conversion costs versus the value of recovered byproducts, cost of acquiring and transporting litter from farms, and shipping costs to transport the converted products to distributors for fertilizer production. Researchers are also considering densification and long distance transport schemes versus local retail and commercial markets.

“One of the key challenges facing this industry is striking a balance between the needs of the growout farms to continue using the litter on their fields as a soil enhancer and the needs of an alternative usage scheme to have access to a specific volume of materials to make the economics of the scheme work,” notes Craig Wyvill, project director for the study.

The overall goal of this study is the generation of a road map of options for the industry to consider in future years. Key among the economic considerations is finding the highest end-use value for the products produced. Preliminary estimates, for instance, show the nutrient value of litter for soil enhancement is approximately $28 per ton. As a waste fuel source, this value is less than half that amount. Additionally, the amounts and locations of litter that could be diverted to these alternatives must be assessed. The study team hopes to have a preliminary report available in the fall.