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UBC Theses and Dissertations

Integrating sustainability in municipal wastewater infrastructure decision-analysis using the analytic hierarchy process Galal, Hana Sherin


New regulations from the Canadian Council of Ministers of Environment, released in 2009, require all wastewater treatment plants in Canada to produce effluent of secondary treatment levels. To comply with the new law, many Canadian municipalities using primary treatment plants must retrofit or renew their old systems. There is an increasing pressure from stakeholder groups and policy makers to select new infrastructure using triple-bottom-line (economic, environmental and social) analyses. The present study aims to illuminate how differing preferences among experts from different stakeholder groups influence what is considered to be the ‘most sustainable' wastewater treatment system. Through the use of policy documents, academic literature, and the use of AHP (a decision support tool: Analytic Hierarchy Process) an objectives hierarchy was constructed. The objectives hierarchy was made up of four criteria and 13 indicators. Five wastewater experts were asked to use pair-wise comparisons to score the indicators and criteria of the constructed objectives hierarchy and provide their opinions on the same. In addition, four low foot-print wastewater treatment alternatives were selected for review. One of the participants was asked to rank the four alternatives with regards to their performance on the selected indicators. This ranking, in combination with the rankings of the indicators and criteria, previously made by the five experts, were used to indicate the preferred alternatives for each of the separate participants. Then, the overall prioritization of the alternatives was used to carry out a sensitivity analysis. In terms of results, this study of sustainability indicators for wastewater treatment selection showed that the most contentious indicators among those studied were Initial Costs and Long Term Costs, Effluent Quality and Aesthetics. Additionally, the study showed that the Sequencing Batch Reactor was identified as the ‘most sustainable’ alternative by the average scores of all five participants and separately by four of the five participants.

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