Project at a Glance
Title: Dairy operations: an evaluation and comparison of baseline and potential mitigation practices for emissions reductions in the San Joaquin Valley.
Principal Investigator / Author(s): Dr. Charles Krauter
Contractor: CSU Fresno
Contract Number: 04-343
Research Program Area: Emissions Monitoring & Control
Topic Areas: Agriculture, Ecosystem Impacts, Impacts, Stationary Sources
Dairy operations in California were assumed in 2004 to be major sources of Reactive Organic Gas (ROG) and therefore, ozone formation in the Central Valley. In 2005 this project was proposed to determine the specific sources and components of ROG in emissions from dairies. An advisory group of public agency, industry and academic members was formed to develop the initial plan and supervise revisions in accordance with initial results. Six dairies were selected to be sampled three times each year to evaluate facility and seasonal differences. Ambient air samples were collected initially to identify specific ROG components and develop analytical methods for dairy air samples. The initial data indicated the predominance of alcohols in feed components of dairy ROG emissions and a sampling program was designed to focus on those while also monitoring other dairy ROG sources. The sampling program was conducted by Dr. Charles Krauter at CSU Fresno. The corresponding analytical program was administered by Dr. Donald Blake at UC Irvine. After review of the initial data, in 2006, the advisory group revised the sampling program to reflect the discovery that alcohols from the feeding operations, rather than manure management appeared to be the most significant ROG source. The six dairies were sampled three times from June, 2007 through July, 2008. The highest flux rates were for silage and feed with an average flux rate of 4,229 µg/m2/minute from the vertical silage pile face and 19,170 µg/m2/minute for loose, disturbed silage used for mixing feed. Fluxes from feed were 15,022 µg/m2/min when first placed in the feed bunker, though the rate decreased to 2,929 µg/m2/min as it was consumed. Flux rates for the flush lanes were considerably lower with a rate of 353 µg/m2min prior to the flushing operation that decreased further to 21 µg/m2/min after the flush. Open lots and exercise corrals were similar to the flush lanes. Areas of the corrals where the manure pack was relatively deep had flux rates of 243 µg/m2/min. while the shallow manure pack in the open lots averaged 102 µg/m2/min. The anticipated seasonal effects appear to be less significant than expected. Only emissions from the open lots correlate with surface temperatures, increasing in the summer and declining in winter. When the areas represented by each of these operations were applied to the flux values, it became apparent that feed was the dominant (60%) ROG source, followed by the open lots (25%), flush lanes (8%) and silage piles (7%). These proportions were calculated as an example of a fictitious dairy that was a composite of the six sampled facilities. These percentages would vary when calculated from actual fluxes and facility dimensions but feed would probably remain the dominant source of ROG.
After this California Air Resources Board (CARB) supported project began, several related projects were added to the sampling program at the six dairies. Additional sampling and analytical systems were added as well as the collection of data related to nitrogen compounds, lagoon emissions, land application emissions, silage, feed, manure, soil and compost materials. These related projects are still in progress. Only data related to the CARB contract is complete and reported here. A comprehensive report of all projects related to sampling at these six dairies and other sites will be prepared at the end of 2009.
For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893
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