Methane Oxidation: Field-Scale Test Sections Experiment
Investigators: Florida State University
The newly published EPA rules provide an option for site-specific methane oxidation values other the default value of ten (10) percent and can range from 0% to 35% depending on the methane flux and the cover type. Such a flux reflects the conditions at the landfill and the thickness of soil cover over majority of the landfill. However, there are 3 key challenges in these new rules that might make it difficult to actually use the higher methane oxidation values in the range that EPA has provided:
- The new rule requires that a ZERO oxidation value is to be used for landfills that have a geomembrane (synthetic) cover with less than 12 inches of cover soil for the majority of the landfill area containing waste.
- A 10% oxidation value is assigned for landfills that do not have a geomembrane with a 12 inches of cover soils, and do not have a soil cover of at least 24 inches for a majority of the landfill area containing waste.
- Higher oxidation values of 35% can only be used for landfills that have a soil cover of at least 24 inches for a majority of the landfill area containing waste and for which the methane flux rate is less than 10 and grams per square meter per day (g/m2/d), and the higher value of 25% can only be used for landfills that have a soil cover of at least 24 inches for a majority of the landfill area containing waste and for which the methane flux rate is between 10 and 70 grams per square meter per day (g/m2/d).
However, the actual effect of the conditions noted in the EPA rules have not been fully explored. The primary objective of this study to measure methane oxidation under different cover conditions and calibrate a methane oxidation model already developed by the research team. The collected data will also provide additional information on methane oxidation in 6” to 18” soil covers under different or varying methane loading. It will also provide data to quantify the additional methane oxidation by a 12” thick compost biocover placed on a 6” daily cover.
The proposed field study will evaluate methane oxidation capacities on three previously constructed test sections. The three test sections represent a unique opportunity where LFG is being introduced into soil profiles at a controlled rate. The methane loading to the test sections will be controlled to match the recently published EPA rule on methane oxidation as follows:
- Below 10 g/m2/day
- 10 to 70 g/m2/day
- Above 70 g/m2/day
The results from this research will allow for a comparative analysis of the new EPA requirements with actual field data.