Abstract
This study was carried out on problems and solutions of methane emissions from landfills. Methane, one of the main greenhouse gases (GHGs), has been assessed to have 28 times the global warming potential (GWP) of carbon dioxide over a 100-year time horizon in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). In municipal solid waste (MSW) landfills, methane is generated as a product of the anaerobic degradation of organic waste. United States Environmental Protection Agency (U.S. EPA) estimated that, in 2016, landfill methane emissions in the U.S. were approximately 107.7 million tons carbon dioxide equivalent (Mt CO2 e). And globally, it was estimated that methane emissions from landfilling of solid waste were 794.0 million tons of CO2 e in 2005. At both the U.S. and the global levels, landfilling was the third largest source of methane emissions, after enteric fermentation and natural gas & oil systems. A broad range of topics about methane emissions from landfill are covered in this report, including the gas-generating processes in landfill, the theories about modeling landfill gas generation and emission, the developed models and the current estimates of landfill emissions, as well as the calculation and analysis on several aspects: 1) theoretical maximum methane generation per ton of MSW and actual methane emission per ton of MSW; 2) climate zone statistics about landfill gas generation model parameter, landfill methane generation, emission and recovery; 3) the time series of global landfill methane emissions with regional analysis and per capita analysis. The findings provide both theoretical information and empirical data on landfill methane emissions. Currently, the most widely used model could be the 2006 IPCC Guidelines First-Order Decay (FOD) Method, which has been used by many countries to develop their national greenhouse gas inventories. In recent years, new methods based on direct measurements have been developed, such as the BackCalculation Method used in the Greenhouse Gas Reporting Program (GHGRP).
Table of contents
Chapter one: Introduction
1.1 Background of the study
1.2 Statement of the problem
1.3 Objectives of the study
1.4 Significance of the study
Chapter two: Gas-Generating Processes in Landfill
2.1 Main Processes
2.1.1 Aerobic degradation
2.1.2 Anaerobic degradation
2.2 Landfill Gas Composition Change During the Processes
2.3 Composition of Landfill Gas
2.4 Factors Affecting Waste Generation, Composition & Landfill Gas Generation, Emission
Chapter three: Modeling Landfill Gas Generation and Emission
3.1 Classification of LFG Generation Models
3.2 Structure of LFG Generation Models
3.3 Estimation of Maximum LFG Yields
Chapter four: Developed Models and Current Estimations
4.1 General Models
4.2 Country- or Region-Specific Models
4.3 Current LFG Emission Estimates at the U.S. Level
4.4 Current LFG Emission Estimates at the Global Level
Chapter five: Calculation and Analysis
5.1 Methane Generation and Emission per ton of MSW in the U.S
5.2 Landfill Methane Generation, Recovery and Emission in Different Climate Zones
5.3 Global Methane Emissions from Landfill: 1970-2017 57
Chapter six: Conclusion and Recommendations
References
CHAPTER ONE
INTRODUCTION
1.1 Background of the study
Landfills create a clear and obvious threat to human health as well as a threat to our environment from the hazardous contaminated air emissions emitted from the landfill biodegradation. There are over ten toxic gases released from landfills, of the most serious of which is methane. Methane gas is naturally produced during the process of decay of organic matter. As methane gas is formed, it builds up pressure and then begins to move through the soil. In a recent study of 288 landfills, off-site migration of gases, including methane, has been detected at 83% of these landfill sites. Methane is a more potent greenhouse gas than carbon dioxide.
Studies have shown significantly reduced height among children who live near Love Canal, the chemical waste dump near Niagara Falls, NY. It has also been shown that people living close to landfills suffer from lung and heart diseases from the toxic gasses that are released from the landfill degradation.
The key environmental problem we face as a result of landfills is groundwater pollution from leachates (the liquid that drains or ‘leaches’ from a landfill). Although they intended to protect human beings from toxins, due to natural deterioration the protective barriers only delay the inevitable. When a new municipal landfill is proposed, advocates of the project always emphasize that “no hazardous wastes will enter the landfill”. However several studies have shown that even though municipal landfills may not legally receive “hazardous” wastes, the leachate they produce is as dangerous as leachate from hazardous waste landfills.
Methane, one of the main greenhouse gases (GHGs), has been assessed to have 28 times the global warming potential (GWP) of carbon dioxide over a 100-year time horizon in the IPCC Fifth Assessment Report; its GWP over a 20-year course is 84 times that of carbon dioxide.
In municipal solid waste (MSW) landfills, methane is generated as a product of the anaerobic degradation of organic waste. U.S. EPA estimated that, in 2016, landfill methane emissions in the U.S. were approximately 107.7 million tons carbon dioxide equivalent (Mt CO2 e), accounting for approximately 16.4 percent of total U.S. anthropogenic methane emissions in 2016, and were the third largest source of methane emission, after enteric fermentation (the largest) and natural gas systems. At the global level, it was estimated that methane emissions from landfilling of solid waste were 794.0 million tons of CO2 e in 2005, again, landfilling was the third largest source of methane emissions, after enteric fermentation and natural gas & oil systems.
A broad range of topics about methane emissions from landfills are covered in this report, including the gas-generating processes in landfill, the theories about modeling landfill gas generation and emission, the developed models and the current estimates of landfill emissions, as well as the calculation and analysis on several aspects. The findings provide both theoretical information and empirical data on landfill methane emissions.
As the number of landfills increase the likelihood of leaks increases five-fold. The increase in trash is due to population growth and consumerism. United States population growth is equivalent or marginally lower than most middle to low-middle income developing countries but the American rate of consumption is far greater than any other developed or developing country today. The amount of waste collected in an average American house hold is far greater than that of any developed or developing country in the world today.
1.2 Statement of the problem
The major issue caused with landfill leachates is the leakage of a large number of toxins into fresh water waterways, which ultimately end up in our homes as drinking water or water for everyday use. Since landfills are most often located in and around large bodies of fresh water or in swamps, the pollution often goes undetected. The compounds submerge to the ground, to the ground water, and inevitably to our dinner tables. The pollution is also severely harmful to animal and plant life.
Groundwater contamination may result from leakage of very small amounts of leachate. TCE is a carcinogen typically found in landfill leachate. It would take less than 4 drops of TCE mixed with the water in an average swimming pool (20,000 gallons) to render the water undrinkable. Some surveys conducted have shown that 82% of the landfills have leaks and up to 41% of the landfills had a leak area of more than one square foot. EPA sponsored research shows that burying household garbage in the ground poisoned the ground water. The EPA has stressed that, even with the double liner landfills, the probability of leaking is very high.
1.3 Objectives of the study
To examine the effects of methane emissions from landfills
To examine the problems of methane emissions from landfills
To proffer solutions to the challenges of methane emissions from landfills
1.4 Significance of the study
A broad range of topics about methane emissions from landfills are covered in this report, including the gas-generating processes in landfill, the theories about modeling landfill gas generation and emission, the developed models and the current estimates of landfill emissions, as well as the calculation and analysis on several aspects. The findings provide both theoretical information and empirical data on landfill methane emissions.
