Location: Northwest Irrigation and Soils Research2012 Annual Report
1a. Objectives (from AD-416):
The purpose of this project is to address atmospheric emissions of trace gases from concentrated dairy operations and manure management systems. The goal is to develop emissions factors which will allow decision makers to evaluate the contribution of these constituents from dairy production with other agricultural and industrial sectors and assist in long-term planning efforts aimed at improving air quality and reducing emissions. Additionally, this project examines emissions of bioaerosols from dairy production facilities as well as airborne transport of pathogens during the reuse of dairy wastewater for crop irrigation. This information will be used to determine the potential for off site transport of bioaerosols and pathogens from dairy production, which is a community concern. The specific objectives and goals of the project are listed below (investigator involved and their time commitment). Objective 1. Determine emission rates of gases and bioaerosols from dairy operations. (Leytem 0.3, Dungan 0.2, Bjorneberg 0.2) • Research Goal 1.1. Estimate on-farm emissions of ammonia, methane, nitrous oxide, and carbon dioxide from dairy production facilities to determine emission factors that account for diurnal and seasonal fluctuations in emissions. • Research Goal 1.2. Compare gas monitoring equipment effects on estimates of ammonia and methane emissions. • Research Goal 1.3. Develop on-farm emissions factors for ammonia, methane, and nitrous oxide from dairy wastewater storage ponds based on wastewater characteristics, management practices, and climatic conditions. • Research Goal 1.4. Measure airborne concentrations of culturable bacteria, virus, and filamentous fungi and endotoxins downwind from a concentrated dairy operation to assess diurnal and seasonal variations. Objective 2. Utilize fecal contamination indicators to assess the downwind transport of pathogens in dairy wastewaters delivered via sprinkler irrigation systems. (Dungan 0.3, Leytem 0.2, Bjorneberg 0.1) • Research Goal 2.1. Assess the transport of aerosolized bacterial and viral pathogens generated during the land application of dairy wastewaters using sprinkler irrigation systems.
1b. Approach (from AD-416):
A year long study will determine the emissions of ammonia, methane, nitrous oxide, and carbon dioxide from the barns and wastewater storage pond of a large freestall dairy. Additionally, bioaerosol transport from the barns to downwind locations will be assessed. The emissions of ammonia, methane, and nitrous oxide from dairy liquid storage ponds will also be assessed in order to determine the factors affecting these emissions and develop better methods for predicting emissions from these systems. An assessment of the transport of pathogens from sprinkler irrigation of dairy wastewater will also be undertaken to determine the risk of pathogen drift to human receptors and potential health risks. A better understanding of the type and amount of constituents released into the air from animal production and manure storage areas are expected results. This information will allow us to develop emissions factors and assess the risk of pathogen drift from these systems.
3. Progress Report:
Significant progress have been made on 4 out of 5 objectives of this project. Under Objectives 1a and 1b all trace gas data from a 10,000 cow freestall dairy has been compiled and emission estimates for greenhouse gases (methane and nitrous oxide) and ammonia were calculated. Under Objective 1c, ammonia and greenhouse gas measurements are currently being taken from wastewater ponds at two daries. Under Objective 1d, monitoring of airborne concentrations of bacteria, fungi, and endotoxin was completed at a freestall dairy operation and the results were published in a peer-reviewed journal. Progress is being made under Objective 2, however, current aerosol studies are being conducted using a bromide ion tracer to allow for the optimization of future wastewater experiments.
1. Culturable bacteria concentrations are not affected by sprinkler irrigation. ARS researchers in Kimberly, Idaho, conducted spray irrigation events of dairy wastewater to assess the impact on culturable bacteria concentrations. This research is important since many dairies, particularly those in the arid west, land apply their manure wastewaters using pressurized irrigation devices. During spray irrigation events, pathogens associated with the wastewater can become aerosolized and transported downwind, possibly causing infection in exposed individuals. In this study, the pre- and post-sprinkler bacteria concentrations were determined to be statistically similar in most cases, indicating that culturable viability was not affected when wastewater flowed through the sprinklers. The data suggests that the number of viable bacterial pathogens available for aerosolization will also not be affected by sprinkler type and pressure setting. The results from this study will be particularly useful to regulatory agencies who are performing microbial risk assessments.
2. Trace gas emissions at an open-freestall dairy. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates for trace gases. In this study, ARS researchers in Kimberly, Idaho, determined emission rates for greenhouse gases (methane and nitrous oxide) and ammonia from the animal housing and manure management sectors at an open-freestall commercial dairy. This study is the third completed study aimed at determining emissions from dairy production facilities representative of western dairy production. The results from this research program have been submitted to the U.S. EPA for use to determine emission factors from dairy production facilities. An indirect result of this work has been that a scientist from our facility has been invited to serve on the U.S. EPA Scientific Advisory Board to review EPA’s methodologies for estimating air emission from animal feeding operations and selected by the USDA Climate Change Program Office to assist in the development of technical guidelines and scientific methods for the estimation of entity-scale greenhouse gas emissions. These activities will help our stakeholders obtain the maximum benefit from this research and assist both producers and regulators in determining realistic on farm emissions of ammonia and greenhouse gasses.Dungan, R.S., Leytem, A.B., Bjorneberg, D.L. 2011. Concentrations of airborne endotoxin and microorganisms at a 10,000 cow open-freestall dairy. Journal of Animal Science. 89:3300-3309.