Progress 10/01/08 to 10/01/11
Outputs
OUTPUTS: The covered lagoon monitoring data indicated that nitrogen concentrations will increase enough to require modifications for nitrogen management. This result has been consistent throughout the project, and has been disseminated to the public at intervals during the project period. Results were presented at an EPA-sponsored workshop and field tour on September 18, 2008 held in Clinton, NC. The workshop was entitled: Environmental and Economic Benefits of Capturing Swine Manure Methane, and was well attended by researchers, policy makers, regulators, and farmers. (See agenda and presentations at http://www.epa.gov/agstar/workshop08.html ) An update of monitoring data was provided to an interagency meeting of NRCS and North Carolina Division of Soil and Water Conservation staff on April 29, 2009 in Raleigh, NC. A report containing nitrogen monitoring data was submitted to the North Carolina Pork Council. The extent of increase in nitrogen concentration in the one year following cover installation was explained. This report was made available to pork producers in North Carolina through the NC Pork Council. A final project report containing nitrogen monitoring data was submitted to the North Carolina Pork Council. The extent of increase in nitrogen concentration during the 2.3 years following cover installation was explained. This report will be made available to pork producers in North Carolina through the NC Pork Council. PARTICIPANTS: Mark Rice, Extension Specialist, Biological & Agricultural Engineering Dept., North Carolina State University C. Mike Williams, Director, Animal Waste Management Center, North Carolina State University TARGET AUDIENCES: Pork producers Environmental regulators Policy makers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Environmental Credit Corp. (ECC) received funding from the USDA NRCS Conservation Innovation Grant (CIG) program for the purpose of demonstrating covered lagoons in an innovative carbon credit incentive program. Four swine lagoons on two separate farms in North Carolina were covered. Covers were installed on all four in April, 2008, and monitoring was initiated in May, 2008. Nitrogen concentration data prior to lagoon cover installation are not available. Nitrogen concentrations increased substantially in all four lagoons since cover installation. The amount of increase was determined using the difference in estimated concentrations at the beginning and end of the study. Initial concentrations were estimated using a linear trendline through the first six months of data points. The final concentrations were estimated as the average over the last four months, when concentrations appeared to have stabilized. By this method, the nitrogen concentrations at the Farm 1 increased by 72% and 115% in Lagoons 1 and 2, respectively. At Farm 2, nitrogen concentrations increased by 107% and 102% in Lagoons 3 and 4, respectively. We were not able to collect data to calculate a complete water balance for the system, so we do not know how much of the nitrogen concentration increase is due to exclusion of rainwater from the lagoons and how much is due to prevention of volatilization of ammonia gas. Much of the rainwater was excluded, but evaporation losses were also greatly reduced. We can compare concentrations of other elements to get an indication of the effect of rainwater exclusion. Total phosphorus (TP) is a relatively conservative element in wastewater lagoons and does not have a volatile form. Phosphorus concentrations in the lagoon liquid did not increase during this study, and actually decreased. It does not appear that rainwater exclusion is the main reason for the nitrogen concentration increases. The rapid increase in nitrogen concentrations in covered lagoons that was observed during the monitoring phase of this project has allowed us to alert producers to the likelihood that additional nitrogen management will be required if covers are installed on existing lagoons. These results have also stimulated interest in nitrogen management techniques and, especially, in potential nitrogen recovery technologies. Three approaches to nitrogen recovery were investigated: 1) ammonia stripping, 2) membrane separation, and 3) algal biofuel production. All have problems in terms of immediate application to swine farms in North Carolina. These technologies may be expensive and management intensive, and have not yet been tested enough for swine waste treatment. The technology of lagoon covers can have a beneficial effect on reducing carbon footprint of swine farms in North Carolina, primarily by methane collection and by subsequent energy production from the methane. Nitrogen recovery from the lagoon would have a lesser effect.
Publications
- No publications reported this period
|
Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Current trends in the covered lagoon monitoring data indicate that nitrogen concentrations will increase enough to require modifications for nitrogen management. This likely outcome was presented at an EPA-sponsored workshop and field tour on September 18, 2008 held in Clinton, NC. The workshop was entitled "Environmental and Economic Benefits of Capturing Swine Manure Methane", and was well attended by researchers, policy makers, regulators, and farmers. (See agenda and presentations at http://www.epa.gov/agstar/workshop08.html ) An update of monitoring data was provided to an interagency meeting of NRCS and North Carolina Division of Soil and Water Conservation staff on April 29, 2009 in Raleigh, NC. A report containing nitrogen monitoring data was submitted to the North Carolina Pork Council. The extent of increase in nitrogen concentration in the one year following cover installation was explained. This report was made available to pork producers in North Carolina through the NC Pork Council. PARTICIPANTS: Mark Rice, Extension Specialist, Biological & Agricultural Engineering Dept., North Carolina State University Joseph Stuckey, undergraduate student technician, Biological & Agricultural Engineering Dept., North Carolina State University TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Environmental Credit Corp. (ECC) received funding from the USDA NRCS Conservation Innovation Grant (CIG) program for the purpose of demonstrating covered lagoons in an innovative carbon credit incentive program. Four swine lagoons on two separate farms in North Carolina have been covered to date. Covers were installed on all four in April, 2008, and monitoring was initiated in May, 2008. Nitrogen concentration data prior to lagoon cover installation are not available. Nitrogen concentrations have increased substantially in all four lagoons since cover installation. The increase in nitrogen to date can be estimated using the best fit linear trendline for each lagoon, using the difference in predicted concentrations at the beginning and end of the first year of the study. By this method, the nitrogen concentrations at the Farm 1 increased by 80% and 155% in Lagoons 1 and 2, respectively. At Farm 2, nitrogen concentrations increased by 115% and 133% in Lagoons 1 and 2, respectively. We were not able to collect data to calculate a complete water balance for the system, so we do not know how much of the nitrogen concentration increase is due to exclusion of rainwater from the lagoons and how much is due to prevention of volatilization of ammonia gas. We can compare concentrations of other elements to get an indication of the effect of rainwater exclusion. Total phosphorus (TP) is a relatively conservative element in wastewater lagoons and does not have a volatile form. The slopes of the trendlines for phosphorus concentration were much smaller, indicating a much lesser effect of the covers on total phosphorus concentrations. The phosphorus concentrations at the Farm 1 increased by 13% and 10% in Lagoons 1 and 2, respectively. At Farm 2, phosphorus concentrations decreased by 8% and increased by 15% in Lagoons 1 and 2, respectively. Since the nitrogen concentrations increased much more than did the phosphorus concentrations, it is likely that the increases in nitrogen concentrations are due mostly to increased nitrogen content of the lagoons, and not to a concentration effect from rainwater exclusion. The rapid increase in nitrogen concentrations in covered lagoons that has been observed to date during the monitoring phase of this project has allowed us to alert producers to the likelihood that additional nitrogen management will be required if covers are installed on existing lagoons. These results have also stimulated interest in nitrogen management techniques and, especially, in potential nitrogen recovery technologies.
Publications
- No publications reported this period
|
|