Methane emissions from 20 landfills across the United States using vertical radial plume mapping

Abstract

Landfill fugitive methane emissions were quantified as a function of climate type and cover type at 20 landfills using U.S. Environmental Protection Agency (EPA) Other Test Method (OTM)-10 vertical radial plume mapping (VRPM) with tunable diode lasers (TDLs). The VRPM data were initially collected as g CH 4 /sec emission rates and subsequently converted to g CH 4 /m 2 / day rates using two recently published approaches. The first was based upon field tracer releases of methane or acetylene and multiple linear regression analysis (MLRM) A closed, synthetically capped landfill covered with soil and vegetation with a gas collection system in a humid continental warm summer climate gave mostly background methane readings and average emission rates of only 0.09 g CH 4 /m 2 /day flux when measurable.Implications: The OTM-10 method is being proposed by EPA to quantify surface methane emissions from landfill covers. This study of 20 landfills across the United States was done to determine the efficacy of using OTM-10 for this purpose. Two recently published models were used to evaluate the methane flux results found with VRPM optical remote sensing. The results should provide a sense of the practicality of the method, its limitations at landfills, and the impact of climate upon the cover's methane flux. Measured field data may assist landfill owners in refining previously modeled methane emission factor default values.

Field measurements and modeling to resolve m2 to km2 CH4 emissions for a complex urban source: An Indiana landfill study

“…Vertical radial plume mapping. The vertical radial plume mapping (VRPM) method makes use of an optical remote sensing instrument (ORSI) to quantify the path integrated CH 4 concentrations in a perpendicular plane downwind of the source at five radial distances (Abichou et al, 2010(Abichou et al, , 2012Goldsmith et al, 2012;Hashmonay et al, 2001 Goldsmith et al (2012). The sources of uncertainties in the VRPM method were initially examined by Abichou et al (2010).…”

“…However, significant variability was observed for the VRPM data. We note that Goldsmith et al (2012) reported the standard error and the number of measurements conducted downwind of the intermediate and final cover areas of IN-1. To be consistent with the reporting of the uncertainties for all measurement approaches, we calculated the standard deviation of the VRPM measurements.…”

“…) and the aircraft mass balance approaches (7 and 17 mol s Foster-Wittig et al, 2015;Goldsmith et al, 2012;Hashmonay et al, 2001;Mays et al, 2009;Mønster et al, 2014), we have tools to more quantitatively address diurnal, seasonal, and annual CH 4 emissions from specific sources. Realistically, considering the strengths, limitations, and uncertainties of each method, unraveling the temporal and spatial variability of emissions over a typical annual cycle from complex area sources can benefit from multiple techniques deployed simultaneously.…”

“…Despite more than three decades of literature addressing CH 4 emissions, our understanding of the regional magnitude and variability of emissions from multiple area and point sources remains relatively poor due to complex urban patchworks of industrial, energy, and waste management sources. Currently, with improved instrumentation choices and field measurement techniques during the last decade (Abichou et al, 2010(Abichou et al, , 2012Babilotte et al, 2010; …”

“…Despite more than three decades of literature addressing CH 4 emissions, our understanding of the regional magnitude and variability of emissions from multiple area and point sources remains relatively poor due to complex urban patchworks of industrial, energy, and waste management sources. Currently, with improved instrumentation choices and field measurement techniques during the last decade (Abichou et al, 2010(Abichou et al, , 2012Babilotte et al, 2010; ) and the aircraft mass balance approaches (7 and 17 mol s ) derived from the small daily operational area. Characterized by a thin overnight soil cover directly overlying a thick sequence of older methanogenic waste without biogas recovery, this area constitutes only 2% of the 0.7 km 2 total waste footprint area.…”