An Evaluation of the USEPA Calculations of Greenhouse Gas Emissions from Anaerobic Lagoons
- John A. Lory *a,
- R. E. Masseyb and
- J. M. Zulovichc
- a Division of Plant Science, 108 Waters Hall, Univ. of Missouri, Columbia, MO 65211
b Division of Applied Social Sciences, 223 Mumford Hall, Univ. of Missouri, Columbia, MO 65211
c Division of Food Sciences and Bioengineering, 231 Ag Engineering Building, Univ. of Missouri, Columbia, MO 65211. Assigned to Associate Editor Andrew Sharpley
On 10 Apr. 2009, USEPA proposed and on 30 Oct. 2009 USEPA finalized reporting thresholds for a wide range of human-derived sources of greenhouse gas (GHG) as a first step in establishing emission limits in the United States. The only on-farm source category that required monitoring under the proposed and final rule was methane (CH4) and nitrous oxide (NO2) emissions from manure storage facilities. Our objective was to assess, through a literature review, the methodology used by USEPA to estimate current CH4 emissions from uncovered anaerobic lagoons and the proposed methodology for reporting those emissions under the proposed rule. A review of the performance of uncovered anaerobic lagoons indicates that they are more effective at degrading volatile solids (VS) than predicted using parameters provided by USEPA that had been developed for anaerobic digesters. We also documented errors in the USEPA- and International Panel on Climate Change–estimated methane conversion factors for uncovered anaerobic lagoons. We suggest estimating CH4 emissions from anaerobic lagoons based on VS degraded in the lagoon and B′ (m3 CH4 generated kg−1 VS destroyed). Our estimate of CH4 released from uncovered anaerobic lagoons indicated the regulatory operation size threshold could be at least 65% smaller than predicted by USEPA in the proposed rule. Our calculated estimate of CH4 emissions was substantially greater than the few estimates of CH4 loss based on direct measurements on uncovered anaerobic lagoons. More research is needed before it will be possible to provide definitive estimates of CH4 loss from uncovered anaerobic lagoons.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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