1,720,977 research outputs found
Gas simulation models for solid waste landfills
No full textSanitary landfills remain an attractive disposal route for municipal solid waste, because, in most cases, it is more economical than other alternatives such as incineration and composting. Although the composition of solid waste may very substantially with location and time, organic materials constitute the vast majority of this waste. Organic materials are susceptible to microbial decomposition that result in gas and heat generation within the landfill. The migration of gas away from the landfill boundaries and their release into the surrounding environment, present serious environmental concerns at both existing and new facilities. Mathematical models have been used widely to evaluate gas and heat generation and transport processes in landfills. This article presents a critical review of models designed to simulate biological, chemical, and physical processes responsible for the generation and transport of gas and heat in landfills
Environmental impacts of solid waste landfilling
No full textInevitable consequences of the practice of solid waste disposal in landfills are gas and leachate generation due primarily to microbial decomposition, climatic conditions, refuse characteristics and landfilling operations. The migration of gas and leachate away from the landfill boundaries and their release into the surrounding environment present serious environmental concerns at both existing and new facilities. Besides potential health hazards, these concerns include, and are not limited to, fires and explosions, vegetation damage, unpleasant odors, landfill settlement, ground water pollution, air pollution and global warming. This paper presents an overview of gas and leachate formation mechanisms in landfills and their adverse environmental impacts, and describes control methods to eliminate or minimize these impacts.<br/
Migration and atmospheric emission of landfill gas
No full textGas generation due primarily to microbial decomposition is an inevitable consequence of the practice of solid waste disposal in landfills. Subsequent gas migration within the landfill and its potential emission to the atmosphere are dependent on the pressure and concentration gradients of the gas inside the landfill as well as many factors related to transport properties of the gas itself (viscosity, diffusivity) and the physical characteristics of the waste (permeability, moisture content, porosity). Temperature plays an important role in defining the gas movement because it strongly influences the gas transport properties as well as biochemical processes controlling gas production within the landfill. This paper presents a one-dimensional numerical gas flow model which predicts the time development of the pressure and gas concentration profiles, and the time variation of the total gas emission from landfills. The model accounts for effects of temperature variations with time on gas transport properties and biochemical processes. It was used to simulate gas emission data from the Mountain View Controlled Landfill Project, California.<br/
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Roles and benefits of community involvement in implementing Natural Flood Management in Maziba catchment, Uganda
No full textAs floods increase in frequency and severity, governments are continuously adopting more of the integrated measures of Flood Risk Management (FRM) such as Natural Flood Management (NFM). In Uganda, the government has recently concluded a community flood resilience building project within the Maziba catchment. This article offers insights on this project’s NFM initiatives and highlights the different roles and benefits of the community’s involvement
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