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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Long term operation of engineered anaerobic bioreactors and wetland cells treating zinc, arsenic and cadmium in seepage : results, longevity, cost and design issues.

Duncan, William Fredrick Alexander 30 May 2011 (has links)
At the Trail Smelter, contaminated seepage water is collected and a portion is diverted for treatment to a large pilot-scale wetland system. The design, construction (in stages from 1997 to 2002) and long term sampling (1998-2007) of the wetland system treating high concentrations of zinc, arsenic and cadmium is presented. The final system configuration has been operating year-round since 2002 treating approximately 15,000 L/d. The system is comprised of two vertical upflow anaerobic (compost) bioreactors followed by three horizontal subsurface flow vegetated wetland cells, a slow sand filter and a final holding cell. Operational sampling was done for water quality (metals and various anions), bacterial communities (MPN, PFLA and DGGE) and vegetation (metals content). After several years of operation one of the anaerobic cells was taken apart and rebuilt in 2002. Extensive solid substrate sampling during deconstruction was analyzed for mineralization (SEM/EDS), metals and carbon content (Rock-Eval pyrolysis) to estimate the potential cell life. The system treats seepage with zinc up to 3800 mg/L (average ~ 260 mg/L), arsenic to 3600 mg/L (average ~ 150 mg/L) and Cd to 83 mg/L (average ~ 4.7 mg/L) which are reduced to <0.5 mg/L (<0.02 mg/L for Cd). Vegetation sampling showed variable uptake into exposed plants at much higher levels than control plants. Plant toxicity was experienced in the system. Evapotranspiration and rhizofiltration are the preferred use of plants as opposed to metal hyper-accumulating plants. Bacterial sampling indicated the presence of sulphate reducing bacteria and a diverse anaerobic microbial community throughout the system despite the high metals entering the system. The predicted life of the anaerobic cell by Rock Eval 6 was 18 years with a range from 17 to 21 years, while based on biomass calculations could range from 14 to 34 years. Where wetlands systems can be successfully used, their cost and environmental and social sustainability is very favourable when compared to chemical treatment systems (e.g. lime-dosing systems). Based on author‟s experience at the Trail and other sites, the design issues faced by full scale wetland systems are presented and recommendations made to ensure a successful system. / Graduate
2

Power of place : linking people, history, and nature visions for an interpretive trail on Mission Flats

Middleton, Colette 11 1900 (has links)
It has long been demonstrated that increased appreciation of place initiates stewardship and responsible management of the land. Interpretative design possesses the potential to generate this stewardship through recovering the connections between place and the people that inhabit it. It is essential that interpretation be integrated into the everyday landscape to deepen one's respect of the past and one's commitment to its future. This vision of an interpretive trail in Mission, British Columbia, explores techniques of illuminating place history to inspire and challenge cognitive participation with the landscape. The format of this project begins with a discussion of the values and limits of interpretative methods. Secondly, the study area is introduced through site reconnaissance with special emphasis on historical morphology and social history. Next, interpretive design strategies are explored in conjunction with significant landscape precedents, culminating in a design approach for an interpretive trail on Mission Flats. Six nodes along the trail serve as keystones for this approach, with individual nodes revealing historical processes, both natural and cultural, through design. Akin to Mission Flats, every place is intimately bound to the people and events that have shaped it. Illumination of this connection is the goal of interpretive design. The planning and design phases of development are incomplete without the inclusion of this holistic vision of place. It is therefore imperative that we further explore interpretive design, so that it may be integrated into the oft-impersonal contemporary landscape, for the generation of authentic place identity.
3

Power of place : linking people, history, and nature visions for an interpretive trail on Mission Flats

Middleton, Colette 11 1900 (has links)
It has long been demonstrated that increased appreciation of place initiates stewardship and responsible management of the land. Interpretative design possesses the potential to generate this stewardship through recovering the connections between place and the people that inhabit it. It is essential that interpretation be integrated into the everyday landscape to deepen one's respect of the past and one's commitment to its future. This vision of an interpretive trail in Mission, British Columbia, explores techniques of illuminating place history to inspire and challenge cognitive participation with the landscape. The format of this project begins with a discussion of the values and limits of interpretative methods. Secondly, the study area is introduced through site reconnaissance with special emphasis on historical morphology and social history. Next, interpretive design strategies are explored in conjunction with significant landscape precedents, culminating in a design approach for an interpretive trail on Mission Flats. Six nodes along the trail serve as keystones for this approach, with individual nodes revealing historical processes, both natural and cultural, through design. Akin to Mission Flats, every place is intimately bound to the people and events that have shaped it. Illumination of this connection is the goal of interpretive design. The planning and design phases of development are incomplete without the inclusion of this holistic vision of place. It is therefore imperative that we further explore interpretive design, so that it may be integrated into the oft-impersonal contemporary landscape, for the generation of authentic place identity. / Applied Science, Faculty of / Architecture and Landscape Architecture (SALA), School of / Graduate

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