MITIGATION OF METHANE EMISSIONS FROM SANITARY LANDFILLS AND SEWAGE TREATMENT PLANTS

CHAPTER ONE
INTRODUCTION
Global warming has become a matter of public concern since last few years. This could be mainly attributed to the trapping of enormous quantities of greenhouse gases (GHGs) in the earth’s atmosphere resulting in GHG effect thereby increasing the earth temperature. GHGs emissions are produced from natural as well as anthropogenic sources. Many sources have been recognized for GHG production within the various development sectors such as the energy, agricultural and the waste (Kumar et al. 2004). Municipal waste namely, wastewater and solid waste are the identified sources of GHG emissions mainly methane. A significant amount of the total methane produced and released into the atmosphere results from the anaerobic decomposition of degradable organic wastes. Global methane emissions from wastewater treatment under anaerobic conditions are estimated to range from 30 to 40 tetra grams per year (Tg/year), this represents 8–11% of the global anthropogenic methane emissions. Methane emissions from municipal solid waste (MSW) landfills account for an estimated 3–19% of the global anthropogenic methane emissions (IPCC 1996). The intergovernmental panel on climate change (IPCC) outlines a methodology to address the issues of methane emissions and climate change. This methodology can be summarized in three major steps: first, methane emissions from the identified sources in a certain sector are estimated in what is called GHG inventory, and this provides the baseline data that is needed in all the subsequent steps. Mitigation is the second step that requires the reduction and/or elimination of the causes of climate change through minimizing the net emissions of GHGs. The last step is the development of a set of actions/policies taken to identify, analyze and adapt to the impacts of climate change. Mitigation is the process of analyzing the costs and impacts of different options (practices or technologies) that could alleviate climate change through the reduction of GHG emissions from different sources, or increasing their absorption in sinks.