Progress 02/01/00 to 02/01/04
Outputs
Over the last year whole house tests were conducted in a commercial layer house using in-house composting in which an entire manure pit was littered with a carbon source and composting of the manure within an entire house was studied. At the end of the 331 day test period the volume of manure within the test house was about 60 % that of an adjacent house in which composting had not been performed. Carbon sources of both sawdust and yard trash were used during these experiments with very little difference. Ammonia concentrations were measured over the length of the house both in the manure pit and upstairs within the cage areas. During turning a significant amount of ammonia is generated from the compost. However, this ammonia flux does not last long. In three hours the ammonia concentration had decreased back down to almost that of normal background concentrations. In between turning operations the ammonia concentration within both the manure pit and rows of cages
upstairs were lower than those measured in an adjacent house in which in-house composting was not being performed.
Impacts
The nutrient value of poultry manure produced annually in Georgia has a value of over $60,000,000. However, producers do not receive this value for this valuable product. While intensive animal production systems provide the farmer with an easier way of collecting and storing manure the problem of "disposal" is amplified. In-house composting has the potential to provide farmers with a technique for reducing the total volume of material while also producing a better end product. If markets were further developed, the end products of in-house composting would provide an additional revenue source for poultry growers.
Publications
- Thompson, S. A., A. B. Webster, N. C. Hinkle and W. C. Merka. 2003 Whole In-House Composting of Layer Manure. Georgia Poultry Conference, Athens, GA, September 25, 2003.
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Progress 01/01/02 to 12/31/02
Outputs
In-house composting of layer manure is a manure management system in which pine shavings are placed beneath the cage rows of layer hens so that the birds can directly deposit their manure onto the shavings. On a regular basis the manure shavings mixture is turned. This turning allows composting action to occur in the layer house. The compost product has less odor, better handling characteristics and more potential market value than normal manure. Whole-house in-house composting tests are being conducted in a commercial tunnel-ventilated high rise layer house utilizing a commercial turning machine to turn the manure shavings mixture. A sawdust woodchip mixture 0.25 m in depth and 2.1 m wide was placed beneath each cage row. This depth of material was chosen to provide an ideal carbon to nitrogen ratio after a 6 month period of composting. The sawdust manure mixture is turned regularly two to three times a week to see if in-house composting can also be used as a
potential fly control method within the house. Ammonia concentration within the house of 25 ppm and 15 ppm are being measured at the manure level and at the bird level, respectively. These concentrations are much less than those measured in other houses within the complex in which ammonia concentration of 50 ppm were regularly measured. Fly speck counts of 17 or less are measured within the house which were much less than those measured in any other house within the complex. Compost temperatures of over 60 degrees C are regularly measured within the compost piles one day after turning of the compost. In one line of the in-house composting house dead birds from the entire complex are being composted. It was estimated that this manure management technique provides a positive economic return to the complex based on a depreciation life of five years on the commercial compost turner and the reduced amount of commercial fly control used in the house and feed as well as the savings
associated with composting of the mortality in the house. This positive economic return takes into account the labor associated with turning of the compost and was calculated before any monetary return associated with the production of the compost was assumed. In an adjacent house efforts were made to turn the manure using the compost turner without a carbon source. This was shown to provide no fly control and was quickly abandoned as a potential method for manure management. In an assessment of Georgia's composting infrastructure it was found that 38 facilities were composting 554,000 tons of organic waste material each year. The primary feedstocks included foodwaste (5.1%), agricultural waste (6.5%), yardwaste (9.0%), animal manures (15.3%), municipal biosolids (28.7%) and industrial wastes (35.5%). Factors limiting additional composting include, public opposition, lack of knowledge, and compost markets. Present operational capacity at these 38 facilities could easily be doubled,
allowing for 500,000 tons more waste to be recycled through composting rather than through landfilling. This would help Georgia achieve its goal of 25% waste reduction.
Impacts
Grower response to in-house composting has gained tremendous interest over the last few years and a Georgia manufacturing company has built a modified compost turner which has been brought to the marketplace. This method is showing great promise in whole-house tests in a commercial high-rise layer house.
Publications
- Thompson, S. A., W. C. Merka, A. B. Webster and P.M. Ndegwa. 2001. Reduction in manure weight and volume using an in-house layer manure composting system under field conditions. Journal of Applied Poultry Research. 10, No. 3, pp 255-261. (Available January, 2002)
- Das, K. C., J. D. Governo and S. A. Thompson. 2002. Computer tool for composting process design and cost estimation. Applied Engineering in Agriculture. 17(5):711-718.
- Governo, J. D., K. C. Das and S. A. Thompson. 2002. Compost Wizard, Modeling a Compost Facility. Proceedings of the World Congress of Computers in Agriculture and Natural Resources. March 13-15, Iguacu Falls, Brazil, pp 318-324.
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Progress 01/01/01 to 12/31/01
Outputs
Tests were performed in a tunnel-ventilated layer house using in-house composting in which the birds deposited their manure into woodchip piles which were later turned. After 280 days the volume of the composted manure was almost exactly the same as that of the raw manure. However, for the woodchips treatments one-third to one-half of the final volume of the compost was that of the initial woodchips. During much of the experiments the ventilation fans in the pit area were running, which promoted drying and volume reduction of all the materials within the pit area. The composted material had a density much less than that or dry stacked manure. At the end of the 280 day test period the bulk density of all of the composted materials was much more similar to that of broiler litter rather than that of normal layer manure. Considerations were made to adding additional water back to the composted materials in the pit area to adjust the moisture content of the material to
promote proper composting. During these experiments the compost was turned on a two week basis using a compost turned. The fresh manure cap on the compost pile was incorporated into the compost which fueled the composting process. During parts of thee experiments temperatures in excess of 150 degrees were measured. These temperatures would stay at these extremes for two to three days and then slowly drop back down to slightly above the temperature of the stacked manure.
Impacts
In-house composting can provide commercial layer facilities with a new technique for utilizing their waste materials. This technique can also provide the farmer with a potential final product which has a nutrient value of approximately thirty-nine dollars per ton thus providing growers with additional income. This waste management technique might also have an added benefit in that fewer flies emerged from the compost piles compared to the raw uncomposted manure piles. The results would indicate that a significant amount of fly control could be obtained by simply altering the turning schedule of the compost during period of the year when heavy fly emergence occurs. By turning the piles more frequently the life-cycle of the fly could be broken.
Publications
- Ndegwa, P. M. and S. A. Thompson. 2001. Integrating composting and vermicomposting in the treatment and bioconversion of biosolids. Bioresource Technology. 76(107-112).
- Thompson, S. A., W. C. Merka, A. B. Webster and P.M. Ndegwa. 2002. Reduction in manure weight and volume using an in-house layer manure composting system under field conditions. Journal of Applied Poultry Research. (In Press)
- Das, K. C., J. D. Governo and S. A. Thompson. 2002. Computer tool for composting process design and cost estimation. Applied Engineering in Agriculture. (In Press)
- Governo, J. D., K. C. Das and S. A. Thompson. 2001. Compost Wizard: Modeling a Compost Facility. 2001 World Congress on Computers in Agriculture and Natural Resources Conference Proceedings. Iguazu Falls, Brazil.
- Governo, J. D., K. C. Das and S. A. Thompson. 2001. Modeling the design of windrow composting operations to maximize the bottom line. ASAE Paper No. 017006, St. Joseph, MI. 49085
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Progress 01/01/00 to 12/31/00
Outputs
In-house composting of layer manure is a manure management system in which pine shavings were placed beneath the cage rows of layer hens so that the birds could directly deposit their manure onto the shavings. On a regular basis the manure shavings mixture is turned. This turning allows composting action to occur in the layer house. Utilizing this manure management system the compost product has less odor, better handling characteristics and more potential market value than normal manure. In tests conducted in the naturally ventilated layer house a 39% reduction in manure weight and a 37% reduction in manure volume occurred over that of deep stacked raw manure. In the tunnel ventilated layer house less reduction in manure weight and volume was observed because the compost material was so dry that good composting action would not occur. In this type house the material was actually more like that of broiler litter. However, this material was very easy to handle and had
very little odor. For a tunnel ventilated layer house the material was taken out of the house, stacked and then rewetted to normal compost moisture contents to see if additional composting would occur in the material. The weight and volume of the stacked material is still being observed. The final compost product had a dry-weight nutrient density of 2% N, 8% P2O5 , 16% Ca. and 5% K2O. A 100,000 bird house is estimated to produce approximately 500 tons of dry weight compost per year, this represents an overall value of $40,000. Vermicomposting utlizes worms to digest waste materials. The products of vermicomposting are the worms themselves which are a good protein source and the worm castings. Using vermicomposting, successful bioconversion of biosolids was achieved. Tests performed with bio-solids from a local waste treatment plant was used to determine the manner and rate in which vermicomposting could be used to digest bio-solids. After vermicomposting, the biosolids had significant
reductions in both total solids and volatile solids. Large reductions in soluble N and a significant reduction in soluble P were observed in all products produced after vermicomposting. The digested products from vermicomposting had a substantial reduction in particle size over that of normal compost and had better quality attributes. The quantity of heavy metals found in the compost product were less than the original biosolids. Bioaccumulation of heavy metals was observed in the tissues of the worms. Interest in utilizing vermicomposting on a large-scale in the conversion of waste materials has been shown by some Georgia farmers. Vermicomposting was attempted to digest layer manure. However, the salt content and ammonia concentration of the manure prevented successful utilization of vermicomposting. Tests were conducted to develop a simple procedure which would reduce the salt content and ammonia concentration of the layer manure. These tests are still ongoing.
Impacts
Grower response to in-house composting has gained tremendous interest over the last few months and the Georgia manufacturing company which built the prototype turner has since constructed a modified compost turner which it plans to bring to the marketplace.
Publications
- Ndegwa, P.M., S. A. Thompson, and K. C. Das. 2000. Effects of stocking density and feeding rates on Vermicomposting of Biosolids. BioResource Technology. 71:5-12
- Ndegwa, P. M., S. A. Thompson and W. C. Merka. 2000. A dynamic simulation model in in-situ composting of caged layer manure. Compost Science & Utilization. Vol. 8, No. 3 pp 190-202.
- A. B. Webster, W. C. Merka and S. A. Thompson. 2000. Manure output from a tunnel ventilated high-rise layer house. March, Commercial Egg Tip, Department of Poultry Science, University of Georgia.
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