A real-life application in optimal route planning for the transportation of liquefied petroleum gas (LPG) in Hong Kong was performed to implement the proposed framework. A set of criteria fitting the context of Hong Kong were defined, and various optimal routing solutions with diverse compromise in different objectives were generated. The implementation of the proposed methodologies enables the avoidance of the pitfalls of preference-based techniques and the burden of generating a complete set of possible solutions, and provides decision-makers with an overview of the solution space and the possible trade-offs among the conflicting objectives. The application study demonstrated the effectiveness of the proposed methodologies. In light of the study results and limitations, some recommendations are provided for future research. / Effective and rational routing of DGs is one of the powerful means to mitigate the DG transportation risk. DG transportation involves multiple stakeholders playing different roles and having different objectives that are generally conflicting. The solution of such problem is to search for one or a set of "compromise" solutions rendering the best possible trade-offs for conflict resolution among different objectives. Given the multi-objective nature of the DG routing problem, multi-objective optimization (MOP) becomes a sound framework for analysis and decision-making. / The transportation of dangerous goods (DGs) can significantly affect human life and the environment if accidents occur during the transportation process. Such accidents can result in traffic disruption, fatalities, property and environmental damages. Therefore, safe DG transportation is of paramount importance, especially in high-density-living environments where population and socioeconomic activities are densely distributed over the transportation network. / This research establishes a general framework for optimal route planning for DG transportation in a high-density-living environment. Within the framework, multi-criteria risk assessment and multi-objective route planning can be efficiently solved by novel compromise programming models and high performance algorithms. Non-linearity and non-convexity often exist in the optimal DG routing problem which cannot be solved appropriately by conventional models such as the weighed sum approach. This research has proposed three novel methods to facilitate the generation of a set of optimal solutions on the Pareto front representing various trade-offs among the conflicting objectives. The proposed methodologies give full consideration to decision-makers' inclination and capability in determining the weights for different criteria. The compromise programming procedure allows decision-makers to exercise their preference structures in pursuing desired solutions rendering good compromises among different objectives. The adaptive weighting method approximates the Pareto front with a few suitable solutions to help decision-makers select the most satisfactory route without generating all of them. The genetic-algorithm-based approach uses a set of specifically designed genetic operators to efficiently capture a wide range of Pareto-optimal and near-optimal solutions, from which a decision-maker can choose the most preferred or best compromise one to implement. The diversity of methodologies provides decision-makers with more flexibility in choosing appropriate MOP methods to route DG shipments. / Li, Rongrong. / Adviser: Yee Leung. / Source: Dissertation Abstracts International, Volume: 73-01, Section: A, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 189-203). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

This diploma thesis deals with the methods of population protection from hazardous chemicals in the event of an emergency situation. The theoretical part of the thesis focuses on the analysis of legislation that governs hazardous chemicals and it pays special attention to the risks related to the transportation of hazardous chemicals and their subsequent leakage. The thesis describes selected hazardous chemicals and informs of accidents that have happened recently. It is also pays attention to warnings, evacuation, providing shelter and the means of improvised protection, which is the most important factor for common public. People meet tanker cars transporting chemicals everywhere and every day; therefore, the protection of population should be aimed in this direction. People often do not know how to behave in situations like this. A questionnaire was compiled for research in the practical part; the questionnaire was intended to find out about the level of knowledge among people. Through the evaluation of population informedness and based on the questionnaire results, a suitable form of education was proposed to fill a gap in the knowledge (a pocket guide). At the same time, the questionnaires were distributed among the staff of the Fire and Rescue System with the aim of confirming their preparedness as well. The preparedness of the Fire and Rescue System is also documented by the analysis of photographs from a tactical drill aimed at a leakage of a hazardous chemical during transport.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

8 pp. / The land application (non-hazardous sewage sludge) biosolids has been in practice in Arizona since the 60s.

The objective of this study is to identify and examine potential mechanisms of radionuclide transport as vapor at a high-level radioactive waste repository located in unsaturated fractured rock. Transport mechanisms and processes have been investigated near the repository and at larger distances. Transport mechanisms potentially important at larger distances include ordinary diffusion, viscous flow and free convection. Ordinary diffusion includes self and binary diffusion, Knudsen flow and surface diffusion. Pressure flow and slip flow comprise viscous flow. Free convective flow results from a gas density contrast. Transport mechanisms or processes dominant near the repository include ordinary diffusion, viscous flow plus several mechanisms whose driving forces arise from the non-isothermal, radioactive nature of high-level waste. The additional mechanisms include forced diffusion, aerosol transport, thermal diffusion and thermophoresis. Near a repository vapor transport mechanisms and processes can provide a significant means of transport from a failed canister to the geologic medium from which other processes can transport radionuclides to the accessible environment. These issues are believed to be important factors that must be addressed in the assessment of specfic engineering designs and site selection of any proposed HLW repository.

Methodologies for estimating hydraulic and solute transport properties of unsaturated, fractured rock are developed. The methodologies are applied to networks of discrete fractures for the purpose of estimating steady fluid flow rates and breakthrough curves of entrained solutes. The formulations employ the boundary integral method to discretize the outer rim of each fracture and to solve a two dimensional flow equation within fracture planes. A three dimensional variant of the two dimensional boundary integral method is used to calculate flow through a permeable matrix with embedded permeable fractures. Exterior and interior surfaces are discretized using boundary elements to account for flow between fractures and the matrix, and between the matrix and fractures and the exterior boundaries. Synthetic fracture networks are created using planar fractures of finite areal extent embedded within a three dimensional rock matrix for the purpose of performing sensitivity studies of network hydraulic conductivity with respect to geometric parameters, such as fracture orientation and density. Results of the sensitivity studies show that: (1) The global hydraulic conductivity is linearly dependent on the product of fracture transmissivity and density for fractures of which fully penetrate the rock volume; (2) The effect of correlation between fracture length and transmissivity is to increase the global hydraulic conductivity; and (3) Results using a three dimensional coupled fracture— matrix flow regime compare favorably with analytic results. Flow through variably saturated fracture networks is modeled by assuming a constant capillary head within individual fractures. A free surface is found using an iterative procedure which locates nodal points at the intersection of constant total head and pressure head contours. The simulated free surface compares favorably with an approximate analytic solution and with laboratory results. Simulations indicate the presence of zones of water under both positive and negative pressure, as well as regions of air—filled voids. Travel times and breakthrough curves are determined by integrating the inverse velocity over a streamline, and then summing over all streamlines. For the fracture network examined, travel times decrease with decreasing fracture saturation. The effects of retardation and matrix diffusion are also examined.

No description available.

An analysis was performed of a Texas gulf coast hazardous waste injection well disposal system. The system was complicated by the presence of a fault which transected the injection interval. The existence of the fault presented the potential for enhanced vertical migration of the injected solutes via a tortuous path of interconnected, highly permeable sand units. Evaluation of this potential necessitated a fully three dimensional model which incorporated the arrangement of the alternating shales and sands and their associated discontinuities. Computer run time and memory limitations compelled a dissection of the problem into components, as well as the utilization of a specific mixture of conservative and realistic assumptions. The analysis indicated that within 10,000 years, the waste would advance vertically no further than one hundred feet into the overlying stratigraphy, and laterally no further than 24,000 feet from the point of injection.

Present day society generates large volumes of waste that present an environmental hazard when disposed of in landfills. As our population grows, so does the volume of waste generated and hence the threat to our environment. One method of reducing harmful emissions in landfills is the mechanical-biological pretreatment of waste prior to landfilling. The purpose of this dissertation is to investigate the degree of stabilization of waste in shallow landfills (simulated by test cells) with particular focus on biogas production and quality. Municipal waste was composted in aerobic, open windrows for periods of eight and sixteen weeks. Five test cells, designed and operated according to the PAF model (Pretreatment, Aeration and Flushing) were constructed at the Bisasar Road landfill site. These cells were used to simulate large scale municipal landfill sites. They were filled with fresh and pretreated waste and were used to monitor the dynamics of prolonged aeration and degradation of waste over a period of six months. The cells were monitored on a weekly basis while being aerated. Two flushing events were conducted at the beginning of the passive aeration. Gas emissions were also monitored by recording the methane, carbon dioxide and oxygen volumes per volume of air in probes strategically placed in each cell. These results were then analysed to assess the effect of mechanical-biological pretreatment of municipal solid waste on the emission quality of sanitary landfills and the appropriateness of prolonging the aeration in shallow landfills, as often used in sub-tropical countries. It was found that the design of the test cells was appropriate for the landfilling and stabilization of waste that was aerobically treated. After six months in the test cells, analysis of the waste from each cell showed that the waste was completely degraded. The PAF model, when applied to shallow landfills, is very effective in stabilising waste and would be appropriate for a sub-tropical climate. Waste that is pretreated, placed in shallow landfills, initially flushed and then aerated over a six month period was fully stabilized. The requirement for such treatment would be relatively small amounts of waste, a wet climate and the availability of open space for shallow landfills. This method, therefore, would be very appropriate in a South African context. The major problem with this method may be the generation of large quantities of leachate which will have to be treated and disposed of in an environmentally safe manner. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2006.