Q361. I am required to provide the values of Equations HH-5 to HH-8. How are the waste depth data used?
A361. The rule requires determination of both surface area and waste depth for each area type specified in Table HH-3. e-GGRT requires reporting of waste depth for each area type specified. The waste depths by area type data, although not used directly in the emissions calculations, are being collected for policy analysis purposes. Methane generation is expected to be proportional to waste quantities, so the surface area weighting used to determine the collection efficiency (CE) of the landfill gas collection system may overestimate or underestimate the actual collection efficiency if the different areas have significantly different waste depths. The reporting of waste depths for these areas allows EPA to assess the uncertainties in the collection efficiencies and subsequently in the methane generation and emissions reported using Equations HH-7 and HH-8.