Thesis Abstract

Abstract
Landfills are significant sources of methane emissions, a potent greenhouse gas contributing to global warming. Microbial methane oxidation processes play a crucial role in mitigating these emissions by converting methane into carbon dioxide. Understanding the microbial communities responsible for methane oxidation in landfills is essential for developing effective mitigation technologies. This research project aims to review the current knowledge on microbial methane oxidation processes in landfill environments and evaluate the existing technologies for enhancing methane oxidation rates. The key microbial species involved in methane oxidation in landfills include methanotrophic bacteria such as Methylococcus capsulatus and Methylosinus trichosporium. These bacteria utilize methane as their primary energy source, oxidizing it to carbon dioxide through a series of enzymatic reactions. The activity of methanotrophic bacteria is influenced by various factors, including methane concentration, oxygen availability, and nutrient levels. Understanding the interactions between these factors is crucial for optimizing methane oxidation rates in landfill sites. Several technologies have been developed to enhance microbial methane oxidation in landfills, including biofilters, bioaugmentation, and nutrient addition. Biofilters provide a supportive environment for methanotrophic bacteria to thrive, promoting efficient methane oxidation. Bioaugmentation involves introducing specific methane-oxidizing bacteria into landfill sites to enhance methane removal rates. Nutrient addition, such as nitrogen and phosphorus supplementation, can stimulate the growth of methanotrophic bacteria and improve methane oxidation efficiency. Despite the potential of microbial methane oxidation processes for mitigating landfill gas emissions, challenges remain in implementing these technologies at a large scale. Factors such as the heterogeneity of landfill environments, fluctuating methane concentrations, and competition among microbial species can impact the effectiveness of methane oxidation strategies. Addressing these challenges requires a comprehensive understanding of the microbial ecology in landfills and the development of innovative technologies to optimize methane oxidation rates. In conclusion, microbial methane oxidation processes offer a promising approach for mitigating landfill gas emissions and reducing the environmental impact of methane release. By investigating the microbial communities involved in methane oxidation and exploring innovative technologies to enhance methane removal efficiency, this research project aims to contribute to the development of sustainable solutions for managing landfill gas emissions and combating climate change.

Thesis Overview

Landfill gas containing methane is produced by anaerobic degradation of organic waste. Methane is a strong greenhouse gas and landfills are one of the major anthropogenic sources of atmospheric methane. Landfill methane may be oxidized by methanotrophic microorganisms in soils or waste materials utilizing oxygen that diffuses into the cover layer from the atmosphere. The methane oxidation process, which is governed by several environmental factors, can be exploited in engineered systems developed for methane emission mitigation. Mathematical models that account for methane oxidation can be used to predict methane emissions from landfills. Additional research and technology development is needed before methane mitigation technologies utilizing microbial methane oxidation processes can become commercially viable and widely deployed.