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621.
    
Solid waste management practices in the Eastern Province of Saudi Arabia are reviewed. The officials of various municipalities and agencies responsible for collecting and disposing of municipal waste were interviewed. The refuse generation rate found is in the range of 1.61–2.72 kg per capita per day. The refuse composition data indicate a high percentage of glass, metals, and wood. For storage purposes, 0.2-m3 barrels are used in residential areas and 0.75 to 1.50 m3-capacity containers are used in commerical areas. The present solid-waste collection system is labor-intensive, and a significant part of the budget is spent on collection and haul operations. The unit collection and haul cost is much higher than the unit disposal cost of refuse. The direct haul of refuse is the common practice, and the use of transfer stations has not yet been considered. It is also observed that the disposal methods used at these sites are not in line with modern techniques for refuse disposal. Landfilling and combined burning and landfilling are the common disposal methods at all the sites.  相似文献   
622.
  总被引:1,自引:0,他引:1  
REALM (REsource ALlocation Model) is a generalised computer simulation package that models harvesting and bulk distribution of water resources within a water supply system. It is a modeling tool, which can be applied to develop specific water allocation models. Like other water resource simulation software tools, REALM uses mass-balance accounting at nodes, while the movement of water within carriers is subject to capacity constraints. It uses a fast network linear programming algorithm to optimise the water allocation within the network during each simulation time step, in accordance with user-defined operating rules. This paper describes the main features of REALM and provides potential users with an appreciation of its capabilities. In particular, it describes two case studies covering major urban and rural water supply systems. These case studies illustrate REALM's capabilities in the use of stochastically generated data in water supply planning and management, modelling of environmental flows, and assessing security of supply issues.  相似文献   
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With increasing concerns about rising energy demand and cost, diminishing oil reserves, and climate change, Central American and Caribbean (CAC) nations have the opportunity to become producers of low-carbon sustainable biofuels for domestic consumption and foreign exchange earnings. While the region has a number of comparative advantages for developing a vibrant biofuels sector, including favorable climate and significant agricultural experience, the experience under the favorable Caribbean Basin Initiative (CBI) has exposed significant technical and non-technical barriers that must be overcome. Using information compiled through interviews with industry executives, government policy makers and civil society stakeholders, we provide a critical analysis of this experience focusing on non-technical barriers to investment. Survey results suggest that political uncertainty, poor regulatory frameworks, and lack of institutional commitment and business incentives are the main non-technical barriers. Having laid out the challenges, we propose potential policy positions to stimulate growth of the regional biofuels sector. Results point to the need to prioritize enhancing national legislation, developing risk prevention plans, creating supply and demand side incentives and increasing multilateral collaboration. While these findings are derived from the Caribbean Basin experience, they may also be applicable to small economies in other regions that are considering policies for biofuels industry development.  相似文献   
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