University of Macau / Faculty of Science and Technology / Department of Civil and Environmental Engineering

No description available.

In order to achieve stable and sustainable systems for recycling post-consumer goods, it is frequently necessary to concentrate the flows from many collection points to meet the volume requirements for the recycler. This motivates the importance of growing the collection network over time to both meet volume targets and keep costs to a minimum. This research addresses a complex and interconnected set of strategic and tactical decisions that guide the growth of reverse supply chain networks over time. This dissertation has two major components: a tactical recruitment model and a strategic investment model. These capture the two major decision levels for the system, the former for the regional collector who is responsible for recruiting material sources to the network, the latter for the processor who needs to allocate his scarce resources over time and to regions to enable the recruitment to be effective. The recruitment model is posed as a stochastic dynamic programming problem. An exact method and two heuristics are developed to solve this problem. A numerical study of the solution approaches is also performed. The second component involves a key set of decisions on how to allocate resources effectively to grow the network to meet long term collection targets and collection cost constraints. The recruitment problem appears as a sub-problem for the strategic model and this leads to a multi-time scale Markov decision problem. A heuristic approach which decomposes the strategic problem is proposed to solve realistically sized problems. The numerical valuations of the heuristic approach for small and realistically sized problems are then investigated.

published_or_final_version / Housing Management / Master / Master of Housing Management

published_or_final_version / Architecture / Master / Master of Landscape Architecture

published_or_final_version / Public Administration / Master / Master of Public Administration

published_or_final_version / Geography and Geology / Master / Master of Philosophy

No description available.

Cost-Benefit Analysis (CBA) was applied to evaluate the "Blue Bag" recycling program in Muncie, IN. Data was collected from the Muncie Sanitary District, a waste recovery facility and from a sample of Muncie residents. Results were analyzed descriptively and statistically and compared in terms of environmental performance to a landfilling option. Recycling resulted in greater greenhouse gas (GHG) emissions reduction and also in larger savings in energy consumption compared to landfilling (an equivalent of savings of $25,800.52 per year). A willingness to pay (WTP) parameter ranged from $0-175 in WTP in taxes/rent per year and a $0-52 range for WTP per trash container collected. The mean value of the welfare improvement corresponded with values obtained by other researchers (Hanley and Spash, 1993), totaling $960,797.65 for the WTP in taxes/rent scenario and $412,819.95 for the WTP per trash container collected scenario. The project's Net Present Values (NPV) were negative under the 3, 5 and 7`%, discount rates (-5209,961.75, -8242,477.73 and -S269,187.38 in the case of an optimistic scenario and -S675,244.83, -657.262.23 and -640,288.54 for the pessimistic scenario, respectfully) if environmental impacts were not taken into consideration. Environmental benefits associated with the Blue Bag program impacted results of the analysis - the project's NPVs were positive under the range of 3, 5 and 7% interest rates (510,569.501.26, 9,704,811.17 and 8,951,068.00 for the optimistic scenario and S 10, l 04,218.17, 9,290,026.68 and 8.579,966.84 in the case of pessimistic scenario, respectfully). It is concluded, that if the Blue Bag program is justified on CBA grounds, it can be considered as a profitable initiative from the social point of view; otherwise, the recycling program's costs outweigh its incomes and the existence and continuation of the Blue Bag program may he questioned. Further studies should be conducted in order to comprehensively test the overall social impacts of the program that could affect results presented in this study. / Department of Natural Resources and Environmental Management

The environmental impact of consumer goods is becoming a growing concern in the modern world. With the increasing awareness of our daily impact and our effects on such crises as global warming, there has been a recent push to develop better environmental strategies and new industries focused on sustainability and the recycling of a variety of post-consumer goods. In other words, there is a shift towards turning waste into money in the name of the environment. Urban regions provide the perfect setting for such development. The concentration of post-consumer waste makes the mining of recyclable materials economical and the availability of labor needed to support the emerging sustainable industries sets the stage for social, economic and environmental benefits. There are currently several end-of-life (EOL) options for post-consumer products. EOL scenarios include secondary material reclamation, material reclamation, repurpose material reclamation, and waste disposal. Within each of these EOL scenarios exists a myriad of process permutations ranging from various collection schemes and modes of transportation to material processing standards and new recycled product industries. Due to the variety of EOL options for post-consumer products, there is no straight-forward answer to the question Which EOL option is preferred? Thus, under the guidelines of Life Cycle Assessment (LCA) as standardized by the International Standards Organization (ISO) in ISO14040, with the inclusion of social and economic requirements as well, the various EOL scenarios are compared in several impact categories including energy use, greenhouse emissions, waste generation, social implications and economic viability. The results of this comparative analysis provide insight into the potential of a more sustainable urban environment, which is part of a much larger goal of reducing our daily impact on the world around us. One industry sector that contributes to a rather large amount of post-consumer trash each year, nearly 4.7 billion tons, is the carpet industry. Carpet thus occupies a great percentage of overall dedicated waste space according to product density. Within an urban environment, the burden of such a bulky waste product is more evident; thus carpet is used here as a case study for the social, economic and environmental impacts of material mining in urban regions for the improvement of overall industrial sustainability. A comparative EOL study is conducted comparing the social, economic and environmental effects of secondary material reclamation, material reclamation, repurpose material reclamation, and waste disposal of post-consumer carpet (PCC) within the thirteen county urban region of Atlanta, GA.