Estimating Methane Emission and Oxidation from Earthen Landfill Covers: Fid-Bau Portal

Estimating Methane Emission and Oxidation from Earthen Landfill Covers

Abichou, T. / Yuan, L. / Chanton, J.

Measuring methane emission and oxidation through landfill covers has been well studied. However, numerical methods to estimate methane emission and oxidation are very limited. A simulation model was developed that combined water and heat flow model and a gas transport and oxidation model. The gas transport and oxidation model is able to use dynamic parameters associated with water content and temperature and incorporate into dynamic methanotrophic activity. Four sites were selected to showcase how emissions and oxidation can be estimated knowing cover design, management practices, and climatic conditions. Simulations were performed for scenarios with and without an active gas collection system. Different simulations were performed with and without organic amendments to the soil cover. Thirty-two simulations were conducted under different locations, climate conditions, bottom pressure boundaries, and soil oxidation capacities. Simulations showed that soil covers in subhumid areas can prevent high methane emission with blockage and decent oxidation capacity. In semiarid sites, higher emission was obtained due to the higher air filled void space of the soil. Oxidation capacities in semiarid sites are higher than those in subhumid sites since influxes of methane are higher in semiarid sites. High pressure underneath the cover caused higher emission in all sites. Even with active gas collection system (vacuum pressure), emissions were significant in semiarid climates. Soil oxidation is not only dependent on the potential methane oxidation capacity (Vmaxmax), but also depends on methane availability.