Biotic systems to mitigate landfill methane emissions

Abstract

Landfill gases produced during biological degradation of buried organic wastes include methane, which when released to the atmosphere, can contribute to global climate change. Increasing use of gas collection systems has reduced the risk of escaping methane emissions entering the atmosphere, but gas capture is not 100% efficient, and further, there are still many instances when gas collection systems are not used. Biotic methane mitigation systems exploit the propensity of some naturally occurring bacteria to oxidize methane. By providing optimum conditions for microbial habitation and efficiently routing landfill gases to where they are cultivated, a number of bio-based systems, such as interim or long-term biocovers, passively or actively vented biofilters, biowindows and daily-used biotarps, have been developed that can alone, or with gas collection, mitigate landfill methane emissions. This paper reviews the science that guides bio-based designs; summarizes experiences with the diverse natural or engineered substrates used in such systems; describes some of the studies and field trials being used to evaluate them; and discusses how they can be used for better landfill operation, capping, and aftercare.

Methane Oxidation in Landfill Cover Soils: A Review

“…High-affinity methanotrophic bacteria exist in soils temporarily exposed to CH 4 concentration. Low-affinity methanotrophic bacteria exhibit a high oxidation capacity, with CH 4 levels in the range of 0.8-66 μmol L -1 (Huber- Humer et al, 2008). Low-affinity methanotrophic bacteria are more prevalent in landfill cover soils than are the high-affinity variant (Kightley et al, 1995).…”

“…For simplicity, previous studies have reported that the CH 4 oxidation process in landfill cover soils is accomplished by methanotrophic bacteria (Abushammala et al, 2012;Huber-Humer et al, 2008;Albanna et al, 2007;Stern et al, 2007;Kettunen et al, 2006). Methanotrophic bacteria (Fig.…”

“…However, methanotrophic bacteria have broad differences with respect to their responses to different CH 4 concentrations (Reay and Nedwell, 2004), and they can be classified accordingly as high-affinity or low-affinity methanotrophic bacteria. High-affinity methanotrophic bacteria are characterized by low CH 4 oxidation capacity, which enables them to begin oxidation at low CH 4 concentrations (0.8-280 nmol L -1 ) (Huber- Humer et al, 2008). High-affinity methanotrophic bacteria exist in soils temporarily exposed to CH 4 concentration.…”

“…Several studies have shown that the CH 4 oxidation process in landfill cover is an efficient method of CH 4 emission mitigation (Abushammala et al, 2013a;Huber-Humer et al, 2008;Stern et al, 2007;Huber-Humer, 2004;Hilger and Humer, 2003;Humer and Lechner, 1999). This process takes place in many natural systems and soils without human interference, due to the abundance of several groups of bacteria requiring oxygen (O 2 ) for the oxidation process.…”

A Novel Application in Green Chemical Processing Using Reject Brines and Carbon Dioxide as Raw Materials

“…When we speak today of going green, we generally refer to something broader than global warming. The term today includes efforts to conserve our natural resources, reduce our contributions to landfills, and reduce pollution generally [7][8][9].…”