An Assessment of Ammonia Emissions from Water-holding Structures for Hog Farms: Lagoon and Spray Technology and Potential Environmentally Superior Technologies

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Title: An Assessment of Ammonia Emissions from Water-holding Structures for Hog Farms: Lagoon and Spray Technology and Potential Environmentally Superior Technologies
Author: Rumsey, Ian Cooper
Advisors: Dr Viney P. Aneja, Committee Co-Chair
Dr S.Pal Arya, Committee Co-Chair
Abstract: Globally, the largest source of atmospheric NH3 is domestic animal waste contributing 20-35 Tg of nitrogen per year. In North Carolina, hog waste accounts for 47% of all ammonia emissions in North Carolina. This is the result of a huge increase in hog population since the 1980's from 3 million to 10 million. Currently swine waste is managed using Lagoon and Spray Technology (LST) also known as 'conventional' technology. A LST uses anaerobic lagoons to store the hog waste, and effluent from lagoons is sprayed on surrounding crops as a source of nutrients. This technology lead to a number sources of ammonia emissions, thus there are a number of environmental problems associated with swine facilities. The need for developing sustainable solutions for managing the hog waste problem is critical for shaping the future of hog farms in North Carolina. As a result of this, an agreement between the North Carolina Attorney General and several farming companies was reached to develop environmentally superior technologies (EST's) for swine facilities. The objective of this study was to quantitatively compare the emissions from the water-holding structures at the two LST farms (Moore farm and Stokes farm) and the three EST farms, and to evaluate the effectiveness of each technology. The three potential EST's were (1) EKOKAN: Up-flow Bio-filtration system, located at Brown's of Carolina # 93, (2) BEST: Solids separation/gasification for energy and ash recovery centralized system, located at Corbett # 1,3,4 farms, and (3) Super Soils: Solids separation/nitrification-denitrification/soluble phosphorus removal/solids processing system, located at Goshen Ridge farm. Measurements of NH3 flux were limited to two, two-week long periods, representing warm and cold seasons. These were obtained by using a dynamic flow-through chamber system interfaced to a mobile laboratory containing the ammonia analyzer and the data acquisition system. During the sampling period, environmental parameters such as lagoon temperature, lagoon pH, and TAN were measured, as well as meteorological parameters such as wind speed, wind direction, air temperature, relative humidity, and solar radiation. In order to make a comparison of LST and EST's, an adjustment for differing environmental conditions was needed. This was achieved by the development of a conventional observational statistical model, which was developed by multiple linear regression analysis based on continuous flux measurements from two conventional farms during a warm and cold season. Ammonia emissions from both conventional and EST farms were normalized to the nitrogen excretion (E) at the hog farms to express the emissions as % E. Potential reductions in ammonia were evaluated by comparing % EEST at EST farms with %ECONV at conventional farms. Overall, all three EST's were found to be significant in reducing ammonia emissions. Super Soils was found to be the most effective, with NH3 emission reductions of 94.7% in the warm season, and 99% in the cold season. EKOKAN was found to be the next most effective, with reductions of 71.7 % and 42.7 % for the summer and spring sampling periods, respectively. The two BEST technologies were the least effective. There were large reductions for both Corbett # 1 and Corbett # 3,4 in the fall sampling period, 71.1% and 39.6% respectively. There were through extremely low reductions in the winter sampling period, with reductions of 13.6% for Corbett # 1 and 7.5% for Corbett # 3,4, respectively.
Date: 2004-08-12
Degree: MS
Discipline: Marine, Earth and Atmospheric Sciences

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