Assessment of Greenhouse Gas and Air Quality Benefits of Dairy Digester Installation In California
Quantifying the impact of dairy biogas digesters on air quality and greenhouse gas emissions.
The dairy digester was installed at the project site in 2021 and is in operation. Seasonal field surveys at the dairy site began early in 2022 and will be completed early in 2023. These surveys include not only measurements at different components of the study site, but also road surveys of other dairies in the region. The researchers have met with dairy industry leaders to update them on the status of research and plans.
The researchers are taking advantage of a comprehensive set of seasonal measurements of methane, nitrous oxide, and ammonia emissions and their drivers at a dairy prior to an anaerobic digester being installed. By repeating these seasonal measurements following the installation and operation of the digester, the researchers will be able to quantify the impact of dairy digesters installation on dairy farm emissions at a well-characterized site. In addition, the researchers will measure the stable carbon isotope of methane emissions from dairy farms in the region from public roads will be made.
Verifying the expected greenhouse gas emissions reductions has environmental benefits if leaks or shortcomings in the management system can be identified and mitigated. Further, the project will evaluate emissions of ammonia, an important precursor to the criteria air pollutant PM 2.5, and hence may benefit public health if ways to reduce ammonia emission are identified.
Key Project Members
The Regents of the University of California, Davis Campus
USDA Salinity Lab