MADISON, WI, June, 2010 The approach the U.S. Environmental Protection Agency (EPA) uses to estimate greenhouse gas emissions from agricultural anaerobic lagoons that treat manure contains errors and may underestimate methane emissions by up to 65%, according to scientists from the University of Missouri.
Anaerobic lagoons treat manure on some animal feeding operations prior to application to crops as a fertilizer. Methane, one byproduct of the treatment process, has 21 times the warming potential of carbon dioxide.
A 2007 U.S. Supreme Court ruling mandated the EPA consider greenhouse gases a pollutant. This led the EPA in 2009 to approve greenhouse gas reporting requirements for any facility that annually releases 25,000 metric tons or more of carbon dioxide equivalents to the atmosphere. The objective of these reporting requirements is to quantify emissions as a first step towards developing strategies to reduce greenhouse gas losses.
Direct measurements of methane emissions from anaerobic lagoons are technically difficult and very expensive, so the EPA adopted a calculation method to estimate methane emissions from anaerobic digesters. They relied on the method used by the International Panel on Climate Change (IPCC) in their 2006 worldwide estimate of greenhouse inventories.
An interdisciplinary team of scientists from the University of Missouri evaluated the EPA and IPCC approach to estimate greenhouse emissions from anaerobic lagoons. They reported the results of their analysis in the May-June 2010 issue of Journal of Environmental Quality, published by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.
The team documented errors in the approach, which the EPA and IPCC adapted from a method used to estimate methane production from anaerobic digesters. A literature review of the performance of uncovered anaerobic lagoons indicated that there are import
|Contact: Sara Uttech|
American Society of Agronomy