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281.
A Delphi survey, the Dade Toxics Community Assessment, was used to develop a consensus between citizen and professional members of the Dade TOXICS Task Force, as a part of a public participation project in Dade County, Florida. The results showed an agreement between the two groups on the ranking of the five major problems to be studied by the task force. 相似文献
282.
ABSTRACT: The water-based activity involvement of participants at state and federal and local and private facilities identified by using participation rate groups is examined. No differences between participant groups within activities based on socio-economic characteristics were found. However, groups of highly active individuals were identified at both types of properties. It is suggested that social action system variables be added to traditional social aggregate variables to assist the understanding of leisure involvement. 相似文献
283.
284.
Elwyn S. Krous Joseph P. Wagner Harold L. Parkinson Milton S. Sachs 《Journal of the American Water Resources Association》1971,7(4):810-822
ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied. 相似文献
285.
286.
Processes for managing pathogens 总被引:1,自引:0,他引:1
Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles. 相似文献
287.
The potential effectiveness of a new composite-aggregate capping technology, AquaBlokTM—in physically isolating contaminated, fine-grained sediments derived from an Ohio, Lake Erie tributary—was evaluated in the laboratory. In particular, large-scale settling-column studies were conducted to determine the degree to which composite-aggregate material penetrates into and/or mixes with the sediment, perhaps affecting the degree to which sediment could be physically isolated through capping. Additionally, large-scale flume studies were conducted to determine resistance of the composite-aggregate material to significant and long-term, fluvial-like erosive forces; the resistance of other potential capping materials was also evaluated for comparison. Experimental results indicate that the composite-aggregate material effectively isolates sediment through the formation of a continuous and relatively erosion-resistant, hydrated capping layer atop the sediments. 相似文献
288.
Peter N. Lodal Jonathan L. Mahanes John M. Calvert Joseph M. Keel 《Journal of Loss Prevention in the Process Industries》1995,8(6):331-341
Conventional vacuum relief methodologies are usually protective responses; that is, they accomplish their purpose by substitution of an inert gas (usually nitrogen) for the process gases removed by an external vacuum source, or for condensable vapour collapsed by an internal process mechanism (e.g. condensation). While this approach is theoretically possible for all potential vacuum scenarios, it becomes practically impossible to implement for installations where a rapid phase change can impart near-instantaneous system pressure reductions. The procedure outlined in this paper takes a preventive approach: eliminate the source of vacuum generation before the safe lower system pressure limit is reached. For distillation and other refluxing systems, this vacuum source is usually the main overhead condenser, which is designed to collapse large volumes of condensable vapour. To eliminate the vacuum source requires elimination of the system's ability to rapidly condense vapour. This goal is accomplished by introduction of inert gas directly into the condensing system to ‘blanket’ the heat transfer surface and stop condensation. The procedure determines the rate, amount and location for introduction of inert gas. The required design data include: (i) system starting pressure, (ii) maximum allowable system vacuum, (iii) volume of the condensing system, and (iv) normal system condensing rate. By determining the rate at which the condenser removes vapour volume from the system, and designing an inert gas delivery system to meet or exceed this rate, the vacuum generation potential of the system is effectively eliminated using a much smaller quantity of inert gas than with the more traditional volume substitution methods. 相似文献
289.
Joseph A. Miakisz 《环境质量管理》1995,4(4):53-63
Niagara Mohawk Power Corporation (NMPC), an investor-owned electric and gas utility operating in upstate New York, has incorporated environmental factors into several facets of its operations, including generation and transmission system planning and operations, system electric operations, and system gas operations. This article describes how NMPC has incorporated environmental considerations in its valuation of new and existing generation resources. What makes this effort unique is that not only are existing environmental regulatory requirements reflected in the planning process, but also prospective environmental requirements are incorporated. This article provides an overview of NMPC's generation valuation process and discusses how both existing and future environmental requirements are addressed. 相似文献
290.
Dr. Joseph N. Lekakis 《The Environmentalist》1995,15(1):16-26
Summary Environmental management is linked to decisions concerning sustainable development which peripheral countries would find quite challenging, given their development priorities and their demands for a restricted share in the burden of global environmental protection. This paper examines the Greek experience with the growing awareness of environmental problems in that country and in the light of current efforts to attain economic convergence with its northern European partners. The focus is on the analysis of the role of the political institutional system in sustainable development, embracing the government, the parliament and the political parties, the courts, and the local authorities. In addition, the role of Non-Governmental Organizations (NGOs) is also summarized. The quest for sustainable development holds both positive and negative effects for Greece, and despite development priorities, there are some workable options available to follow a pathway of transition.graduate diplomas from the Institute of Business Management of the Graduate School of Economics and Commercial Sciences, Athens (Greece) and the School of Social Studies, University of East Anglia (UK), an MA in Economics from the University of Kent, Canterbury (UK), and a PhD in natural resources from the University of Michigan, Ann Arbor (USA). Dr. Lekakis served at the Centre of Planning and Economic Research (KEPE) in Athens for over 15 years, where he was in charge of the technical processing of Greece's five-year development plans in the area of environmental protection. He is currently on the faculty of the School of Social Sciences, University of Crete, Rethimno (Greece) where he teaches environmental and resource economics. His most recent research activity includes a just completed international water resource allocation project financed by the European Science Foundation (ESF), and an ongoing project on the institutional adjustment for sustainable development strategies in the European Union. 相似文献