1,721,103 research outputs found
Wastewater management along the Mediterranean Coast: A treatment application decision case study central Platte Valley
No full textThe Council for Development and Reconstruction, which needed to make decisions regarding the development of a wastewater management plan for the City of Beirut, was in the process of selecting a final site location and a treatment alternative for a facility along the Mediterranean coast. Environmental, technical, and socio-economic considerations constituted the basic issues to be addressed in the decision-making process. In this respect, proponents of the new wastewater treatment plant stated that it would provide many environmental and economic benefits to the area, particularly in terms of job creation and elimination of health hazards. Opponents of the plant, however, stressed that there was no need for the plant and argued that the wastewater should continue to be directly discharged into the Mediterranean Sea. They claimed that the dilution and treatment potential of seawater is adequate as a wastewater management approach and questioned the economic priority of constructing new treatment facilities in the country because of more urgent needs in other sectors, particularly since treatment facilities were being financed through international loans. Despite some public opposition, environmental concerns and international pressure led the Council to adopt a management plan that required wastewater treatment prior to final discharge. The council however, needed to decide on criteria for locating treatment facilities, determine the level of treatment, and select the final discharge media.<br/
Environmental impacts of waste disposal in rivers and estuaries along the coast of Lebanon
No full textPredicted performance of clay-barrier landfill covers in arid and semi-arid environments
No full textConventional landfill cover systems for municipal solid waste include low-permeability compacted clay barriers to minimize infiltration into the landfilled waste. Such layers are vulnerable in climates where arid to semi-arid conditions prevail, whereby the clay cover tends to desiccate and crack, resulting in drastically higher infiltration, i.e., lower cover efficiency. To date, this phenomenon, which has been reported in field observations, has not been adequately assessed. In this paper, the performance of a cover system solely relying on a clay barrier was simulated using a numerical finite element formulation to capture changes in the clay layer and the corresponding modified hydraulic characteristics. The cover system was guided by USEPA Subtitle-D minimum requirements and consisted of a clay layer underlying a protective vegetated soil. The intrinsic characteristics of the clay barrier and vegetative soil cover, including their saturated hydraulic conductivities and their soil-water characteristic curves, were varied as warranted to simulate intact or “cracked” conditions as determined through the numerical analyses within the proposed methodology. The results indicate that the levels of percolation through the compromised or cracked cover were up to two times greater than those obtained for intact covers, starting with an intact clay hydraulic conductivity of 10?5 cm/
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