Design of Microbial Methane Oxidation Systems for Landfills

Abstract

Landfill methane currently represents the largest global source of greenhouse gas emissions from the solid waste sector. Emissions are expected to increase due to increasing waste generation, particularly in countries still landfilling biodegradable wastes. As a complementary measure to gas extraction with subsequent flaring or energy conversion, or for emissions reduction from old landfills or from landfills containing wastes with a low gas potential, microbial methane oxidation systems (MMOS) are considered a promising technology. Numerous studies relating to controlling factors and enhancement of microbial methane oxidation in biocovers, biowindows or biofilters, both in laboratory and in large scale field settings, have been published. The design of optimized MMOS requires thorough understanding of the involved processes, specifically the biological ones and of those related to the transport of gas and water in porous media, and of the impact of material properties and external environmental factors on these processes. Consequently, the selection of materials that are suitable from a biogeochemical and from a geotechnical point of view, meeting the required water and gas transport properties, are key aspects in the design process. This paper reviews the scientific background of the relevant concepts and processes dictating MMOS performance, and provides guidance on layout and design steps, including choice of materials and quality control. Further, a decision tree to support the choice of MMOS is proposed. This paper provides the scientific foundation for upcoming technical guidance documents.

An In-Depth Analysis of Physical, Chemical, and Microplastic Parameters of Landfill Fine Fraction for Biocover Construction

“…In our study, the BD in only two layers was lower than the recommended value, highlighting the importance of an in-depth analysis of fine fraction parameters. Bulk density is a critical parameter for efficient biocover functionalization, as it influences porosity and the movement of air and gases, particularly oxygen and methane [35]. Adequate aeration supports the activity of aerobic microorganisms involved in methane oxidation and impacts the efficiency of the reduction in methane emissions.…”

Role of Microbes in Mediating Methane Emissions

“…In addition, biocovers can be constructed solely of either compost or a mineral soil alone . Of these options, organic material provides water-holding capacity and gas permeability, but mineral soils may be more resilient over time because they do not decompose and do not demand as much oxygen through aerobic decomposition of the compost (Gebert and Gröngröft 2006;Gebert et al . 2022) .…”

Effects of Fir-Wood Biochar on Ch4 Oxidation Rates and Methanotrophs in Landfill Cover Soils Packed at Three Different Proctor Compaction Levels

“…The global warming potential (GWP) of CH 4 is 28 over 100 years and as high as 84 over 20 years (IPCC, 2021), making landfills a priority sector that necessitates a reduction of climate forcing emissions. One option is to optimize microbial oxidation of CH 4 in landfill biocovers, complimenting active gas extraction systems to fully reduce the long-term low-calorific methane fluxes after active gas extraction terminates (Gebert et al, 2022;Huber-Humer et al, 2008;Scheutz et al, 2009). Landfill biocover technology promotes the activity of methane-oxidizing bacteria (MOB) by enhancing soil properties favorable to methanotrophic activity.…”