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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #307202
Title: Accuracy of vertical radial plume mapping technique in measuring lagoon gas emission

Author
item VIGURIA, MIALEN - University Of Basque Country
item Ro, Kyoung
item Stone, Kenneth
item Johnson, Melvin - Mel

Submitted to: Journal of Air and Waste Management Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2014
Publication Date: 3/23/2015
Citation: Viguria, M., Ro, K.S., Stone, K.C., Johnson, M.H. 2015. Accuracy of vertical radial plume mapping technique in measuring lagoon gas emission. Journal of Air and Waste Management Association. 65(4):395-403.

Interpretive Summary: Recently, the U.S. Environmental Protection Agency (USEPA) posted a ground-based optical remote sensing method on its website called other testing method (OTM) 10 for measuring fugitive gas emission rate from closed landfills. This study evaluates the accuracy of the OTM 10 in measuring gas emission from animal waste treatment lagoons. A field trial was designed to evaluate the accuracy of the OTM 10 technique. Control releases of methane gas were made from a 45 meter (m) x 45 meter(m) floating perforated pipe network located on an irrigation pond that resembled typical treatment lagoon environments. The accuracy of the OTM 10 technique was expressed by dividing calculated emission rates to actual emission rates. Under an ideal condition of having mean wind directions mostly normal to a downwind vertical plane, the average OTM 10 accuracy was 0.75 ± 0.28. However, when mean wind direction was mostly not normal to the downwind vertical plane, the emission plume was not adequately captured resulting in lower accuracies. The accuracies of these non-ideal wind conditions could be significantly improved if we relaxed the OTM 10 wind direction criteria and combined the emission rates determined from two side-by-side downwind vertical planes surrounding the lagoon. With this modification, the OTM 10 technique accuracy improved to 0.90 ± 0.35 while the number of valid datasets also increased from 113 to 186.

Technical Abstract: Recently, the U.S. Environmental Protection Agency (USEPA) posted a ground-based optical remote sensing method on its website called OTM 10 for measuring fugitive gas emission flux from area sources such as closed landfills. The OTM 10 utilizes the vertical radial plume mapping (VRPM) technique to calculate fugitive gas emission mass rates based on measured wind speed profiles and path-integrated gas concentrations (PICs). This study evaluates the accuracy of the VRPM technique in measuring gas emission from animal waste treatment lagoons. A field trial was designed to evaluate the accuracy of the VRPM technique. Control releases of methane gas (CH4) were made from a 45 m x 45 m floating perforated pipe network located on an irrigation pond that resembled typical treatment lagoon environments. The accuracy of the VRPM technique was expressed by dividing calculated emission rates (QVRPM) to actual emission rates (Q). Under an ideal condition of having mean wind directions mostly normal to a downwind vertical plane, the average VRPM accuracy was 0.75 ± 0.28. However, when mean wind direction was mostly not normal to the downwind vertical plane, the emission plume was not adequately captured resulting in lower accuracies. The accuracies of these non-ideal wind conditions could be significantly improved if we relaxed the VRPM wind direction criteria and combined the emission rates determined from two side-by-side downwind vertical planes surrounding the lagoon. With this modification, the VRPM accuracy improved to 0.90 ± 0.35 while the number of valid datasets also increased from 113 to 186.