When mining activities in some parts of the Witwatersrand were discontinued in 2000, the defunct workings started to flood. In September 2002 the mine water started to decant from the West Rand Mine Basin (WRB) next to the Tweelopie East Stream. Treated water is currently used in the mine's metallurgical plants and 15Ml per day of treated water is disposed firstly into the Cooke Attenuation Dam and then discharged into the Wonderfonteinspruit. The aim of this study was to find and provide remediation measures as a result of acid mine drainage and other impacting factors on the water quality and volume in the Wonderfonteinspruit. Conductivity and total dissolved solids (TDS) were highest at the point where the tailings dam leached into the Wonderfonteinspruit. Sulphate was very high as was expected due to acid mine drainage. The best way to treat the high sulphate levels is with sulphate-reducing bacteria. To avoid the fatal flaw of many other constructed wetlands, a continuous carbon source is provided to the bacteria in the form of activated sewage from the Flip Human sewage treatment plant. Iron and other heavy metals are being precipitated through oxidation reactions to form oxides and hydroxides from the aerobic cell in the wetland. The wetlands are also known for their ability to reduce nitrate and microbial values with great success. In the remediation, four elements that currently do not comply with the SABS criteria for class 0 water, were chosen for improvement: conductivity, dissolved solids, sulphate and iron. Conductivity falls within class 1 and has a maximum of 178 mS/m @25ºC that should be reduced to under 70 mS/m. Total dissolved solids have a value of 1585 mg/l, which is much higher than the prescribed 450 ml/l, making it class 2 water. The last two problematic elements are both considered as class 2 water: sulphate peaks at 592 mg/l where the preferred value is 200 mg/l, and iron should be 0.01 mg/l, not the staggering 0.3mg/l. iv Alternative mitigation methods were identified and analysed for the impacts of the five major contaminators and ultimately the solution comes down to constructed wetlands. This is not a straightforward solution, however, and a specific design to accommodate all the different pollutants and water quality ranges was proposed. The other mitigation methods include a cut-off trench and pump-back system for the tailings dam, as well as the implementation of a monitoring programme. The sewage works should be optimised and better managed. Both the settlement and agricultural sector need to be educated on their representative impacts on the environment and government assistance should be available. / ENVIRONMENTAL SCIENCES / MSC (ENVIRON MANAGEMENT)

This dissertation evaluates the role and effectiveness of law in the transboundary environmental governance of the Baltic Sea with regard to eutrophication. To this end, it reviews the applicable international agreements with their related instruments, as well as the EU legal frameworks, for the protection of the Baltic Sea environment on the basis of theories on resilience in social-ecological systems. The scientific discourse on resilience in social-ecological systems provides theories on effective governance of complex environmental problems with nonlinear causal connections. The governance features identified in resilience governance also show significant similarities with characteristic features of the concept of ecosystem approach. The resilience features can thus provide guidance to the operationalization of this concept, which lacks a distinct meaning in the legal context. Eutrophication is one of the main environmental problems in the Baltic Sea. Despite the fact that this problem has been acknowledged since the 1970s, only little progress has been visible in the attempts to limit the problem. Environmental governance in the form of cooperation and common action has, however, been established by the coastal states of the Baltic Sea to reduce the discharges to their common resource. This was originally coordinated through the Helsinki Convention and its administrative organization HELCOM in the 1970s. Since the year 2000 a new set of legal instruments and approaches have developed, emphasizing also the ecosystem approach. These instruments have a basis both in HELCOM and in EU environmental law, most significantly represented by the Water Framework Directive and the Marine Strategy Framework Directive. They establish a unique regulatory structure, with new approaches to regulation, which also give rise to questions regarding interpretation and effectiveness that have not previously been analyzed. It is concluded that applicable law in the Baltic Sea area reflects resilience features such as adaptability, flexibility and redundancy within the legal structure. The legal structure for the Baltic Sea is dynamic and stretches over many levels of governance. The applicable legal instruments are constructed so as to be adaptable and flexible. The legal instruments moreover include significant elements that provide for participation at different levels and in different forms, which contribute to enabling the mentioned resilience features. However, the Baltic Sea legal structure – as law in general – has different core functions than just providing for effective environmental governance. Law is based in a number of general principles connected to the rule of law and the function of law as a foundation for stability in the society and in human interactions. These principles are also important since they are directly linked to enforcement, monitoring and control. While the legal structure in the Baltic Sea may provide for effective governance and social-ecological resilience, the resilience features reflected in law do not always appear as far-reaching as suggested by resilience theories, much due to the legal principles. It is however because of these principles and the base for binding requirements they enable, that law can push for governance measures and features that might not have been accomplished otherwise. This, in the larger perspective, includes creating requirements that steer human activities away from critical thresholds. / Baltic Ecosystem Adaptive Management, BEAM

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利益團體影響政府政策的制定，在各國均時有所聞。本文主要探討當政府面對利益團體的政治獻金操作時，在謀求社會福利水準極大下，將如何影響污染管制政策的制定。藉由 Grossman and Helpman (1994) 所建立之政治獻金模型為架構，分析利益團體如何藉由政治獻金的捐獻來達成影響政府制定最適污染管制政策的目的；並藉由此一模型分析政府如何在考量政治獻金的收入下，訂定最適污染管制政策。我們發現廠商及一般民眾所提供政治獻金的多寡及最適污染標準的高低，受到政府對全國福利水準重視的程度，及一般民眾組成利益團體的人數所影響。當一般民眾組成利益團體的人數愈多時，政府制定之最適污染標準將愈趨於嚴格，尤其全體民眾組成一共同利益團體時，最適污染標準值將與未收受政治獻金時之數值相等。然而一般而言，政府所制定最適污染標準值卻是較有利於廠商。 / This paper analyzes how the interest groups use political contributions to influence the government optimal control policy of pollution. We find that both the optimal control of the pollution and the amount of political contributions are affected by the weight that the domestic government puts on the social welfare and the population. When the weight is larger, the political contributions of interest groups will become smaller. Secondly, the more people pay attention to pollution, the more strict the optimal control of the pollution will be. Moreover, in general, the optimal control of the pollution tends to favor the manufacturer.

Ph.d.-afhandling. Danmarks Tekniske Universitet, 2006. / Haves også i trykt udg. Thesis (Ph.D.). 11 ill., 6 tables; approx. 260 ref. Summaries (Da, En).

M. Tech. Chemical Engineering. / Discusses the HybridICE filter as a new but economical device for separating the ice from the slurry in freeze desalination processes. There is no direct information in the literature on the filter so there is a need to describe the principles behind the operation. There is also a need to investigate the filtering process in order to increase yield and purity of the ice produced. No design method exists for the filter. A design method has to be established so that when the required flow-rate is determined, the dimensions of the filter can be calculated.

Reducing automobile-based gasoline consumption has been a major U.S. public policy issue recently. A key driving force behind policymakers' desire is the concern of environmental externalities and national security. Currently, there are three public policies towards reducing automobile gasoline consumption: raising federal gasoline tax, raising the Corporate Average Fuel Economy (CAFE) Standards and vehicle scrappage subsidies of government to retirement of old vehicles. My research studies the effectiveness of these policies in the United States. Among all polices, economists often argue that higher gasoline tax would be more effective in improving fuel economy efficiency. In my first chapter, I ask how gasoline prices influence households' automobile replacement decisions and thus market fuel economy efficiency, which is measured by average mileage per gallon in a city. I specify and estimate a structural dynamic model of consumer preference for new and used vehicles following the methodology proposed by Gowrisankaran and Rysman (2009). Since gasoline costs accounts for 65% of total operating costs, the current and future gasoline price must need to be taken into consideration for rational forward-looking consumers when they are making vehicle choices. Besides, the replacement decision for vehicles is dynamic as well: facing depreciation as the automobile ages and the improving features for new products, consumers need to decide whether to replace the vehicle in the current period or later. Therefore, a dynamic model of consumer choice would be crucial to correct policy evaluation of fuel economy efficiency, while previous literature fails to consider the dynamics. By taking dynamics into consideration, I am able to capture the inherent dynamic nature of a forward-looking consumer's decision, with rational expectation on the evolution of vehicle attributes and retail gasoline prices. I estimate the model using a rich dataset combing vehicle registration data on different cities, vehicle characteristic data, average gasoline price, etc. Although a high gasoline tax is never put in practice in the U.S. and may not be political feasible, I further conduct an experiment of raising gasoline tax to test how fuel economy efficiency is affected based on my model estimates. Experiments suggest that keeping a $4 gasoline price would result in a steady trend for a city's fleet fuel efficiency increase, while doubling current rate will only increase fuel efficiency in the first several years, but experience drops over time. The Corporate Average Fuel Economy (CAFE) are regulations in the United States that intended to improve the average fuel economy of cars and light trucks sold in the US. However, it is long been realized that with a more fuel efficiency car, consumers may be induced to drive more which partially offsets the original energy saving by the policy. Therefore, to assess the effectiveness of CAFE standards, it is crucial to ask: how fuel economy efficiency, which is measured by mileage per gallon (MPG), affects households' vehicle mileage traveled and its distribution. In my second chapter, I answer the question by estimating a structural model for joint determination of vehicle fuel efficiency choice and vehicle mileage traveled each year with a detailed micro-level data of National Household Travel Survey 2001. I further study the distributional effects on vehicle miles of fuel efficiency using instrumental quantile regression. Comparison on results and tests of weak instruments between my method and literature suggest that my model and choice of instruments provide consistent estimates, while using choice probabilities as instruments is not valid. My results support some earlier findings of rebound effects with a more precise quantitative estimation. In addition, I find new evidence that costs associated with raising CAFE standards vary across different quantiles of annual mileage driven and are especially high for those with below-average vehicle mileage driven. These findings also provide rationale in support of a tax on mileage, which is more effective in reducing gasoline consumptions, comparing to the costs of CAFE standards. My third chapter focus on 2009 CARS Program (Cash-for-Clunker). The 2009 CARS program attempted to boost the sale of new fuel efficient vehicles to replace old gas guzzlers. The program established a two-tier incentive system depending on whether buyers purchased a passenger vehicle or an SUV. The result is that many of the new purchased vehicles are indeed SUVs. The CARS program collected information about the old scrapped vehicles and linked it to the actual purchase of the new vehicles. It is thus possible to analyze the effect of preference inertia in choices by comparing the characteristics of old and new vehicles. The fact that effective prices that consumers face are determined by the mileage class of the old car also allows us to evaluate the distribution of valuation trade-offs between mileage and other characteristics such as size, performance, and vehicle class. My findings suggest that the 2009 Cash-for-Clunker is not very effective in terms of affecting consumers' choice of SUVs and big cars. For transactions under the program, consumers still prefer SUVs and large cars. The extra $1000 rebates actually increase consumers' tastes towards SUVs. / text

This thesis presents an analysis of air quality control initiatives in the GVRD. Starting with an examination of deteriorating regional air quality, oxides of nitrogen emissions (NOx), are the focus (as a precursor to ground level ozone.) The research demonstrates that if the status quo is maintained, episodes of ground level ozone will get worse and the effects will be far reaching and expensive. The Greater Vancouver Regional District's Air Quality Management Plan is reviewed, with emphasis on analysis and evaluation of emission reduction strategies. Emission Reduction Measures (ERMs) are various methods of reducing air pollution (including scrubbers on smoke stacks, transportation demand management, alternative fuels and motor vehicle inspection/maintenance programs.) Emission Reduction Measures are viewed as the tools that must be implemented to solve air quality problems. Environmentally, the most desirable solution would be to implement all ERMs. However, factors such as cost effectiveness and social, financial, political and customer service impacts must be considered and the best measures should be implemented first. The best solutions are those that meet as many objectives as possible while causing the least amount of negative impacts on the economy, society, government and the environment. Finding optimal solutions is a task that requires formalization of common sense. Analytical frameworks such as the cost/benefit analysis, decision analysis and the multiple account/objective analysis are considered as potential tools to help "make sense" of the complexity of air quality policy decisions. The intent is to provide useful and readily understandable information to decision makers. The Multiple Account Analysis (as used by The Crown Corporations Secretariat) is applied to an assortment of Emission Reduction Measures to help identify the "best" order for implementation. This method provides results that compare accounts of importance (such as cost effectiveness and emission reduction potential) and presents decision makers with quality information highlighting tradeoffs and preferences. In the scope of this paper, four ERMs are analyzed across accounts and the results presented in a matrix. The AirCare Program appears as the best choice for effective reduction of oxides of nitrogen when compared to alternative fuels, vanpooling and the Burrard thermal generating plant rebuild.

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Made available in DSpace on 2014-10-09T12:27:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:35Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP