Year

2009

Degree Name

Master of Engineering - Research

Department

School of Civil, Mining and Environmental Engineering

Abstract

This research examines the sustainability of small water and wastewater systems for remote settlements in Central Australia, and develops a multi-criteria assessment framework to compare the performance of technologies for use in such systems. The sustainability of water and wastewater systems has been the subject of considerable research, for both centralised and decentralised systems in developed and developing countries. The use of Multi Criteria Assessment (MCA) to solve sustainability-oriented water and wastewater problems has also been the subject of prior research in a variety of settings. Both these fields have emphasised the need for locally determined definitions of sustainability and MCA processes which reflect the reality of the stakeholders who will be influenced by project outcomes. Such research has only been carried out to a limited extent in relation to the small, self-managed water and wastewater systems which are typical of remote settlements in Central Australia. The work undertaken as part of this project aims to fill that gap. The research had two aims. The first was to develop a picture of water and wastewater systems sustainability that was relevant and applicable to remote Central Australian settings. The second was to use that vision of sustainable systems to design a multicriteria assessment framework which could be used to compare and evaluate water and wastewater treatment technologies for use in those settings. Both qualitative and quantitative methods were used to achieve these aims. Firstly, a qualitative pre-scoping study was carried out to gain an understanding of the conditions and settings at remote Central Australian sites. This involved site visits and discussions with the person responsible for the water system at each site. The outcomes informed the full scoping study into systems sustainability, in which interviews and focus groups with experts and different types of users in Central Australia were undertaken to discuss systems, technologies and the issues faced in water and wastewater provision. Analysis of these results led to the development of the overall sustainability framework for water and wastewater systems. Further analysis relating to what respondents were saying specifically about technologies contributed to the development of the sustainability oriented multi-criteria assessment process for assessment of technologies. A telephone survey of users was then carried out to determine the weightings for different criteria in the MCA process. Technology manufacturers were also surveyed to obtain data on technology performance against the criteria, which was then input to the analysis. Different weighting and scoring methods were used to examine the sensitivity of the model and the analysis itself was carried out in Microsoft Excel. It was found that systems sustainability is made up of five dimensions for remote settlements in Central Australia – economic, social, environmental, technical and institutional. Principles, criteria and indicators of sustainability were developed for each of these dimensions. The MCA framework consisted of 13 criteria relating to the economic, social, environmental, technical & institutional performance of technologies. The commercially available technologies considered for water purification were all small reverse osmosis units with a permeate production capacity of up to 2,000L/day. The reason these units were chosen is that the primary reliable source of water for most sites in remote locations is groundwater, and salinity of groundwater often represents a barrier to its use as a potable source. The technologies assessed for wastewater treatment are all commercially available units designed for sites not connected to a centralised sewerage system. They represent a range of treatment methods, namely aerobic treatment, membrane bioreactors and packed bed treatment. Chlorination and ultraviolet tertiary treatment options are considered in combination with these where they were available as part of the unit. The assessment of water technologies found two units which out-performed the others. The results varied depending on the weighting and scoring method used, and there were some differences between user groups. The assessment of wastewater technologies showed that one unit was the best performer across every combination of weighting and scoring bar one. Areas in which further technology development should be undertaken for improved performance have included modularity of technologies; robustness in harsh conditions; simplicity of operation and maintenance and regulatory compliance. The sustainability model developed for water and wastewater treatment in remote settings could be used to: • Assess the sustainability of existing water and wastewater systems, by examining their performance against the indicators • Assist in planning new systems to ensure that they will be sustainable, by making sure that steps are in place to fulfil each of the indicators • Examine policy or funding decisions related to service provision which may impact on any of the criteria or indicators either positively or negatively. The multi-criteria assessment framework can be used to compare technologies and assess relative sustainability performance. The adoption and use of these two tools should lead to more sustainable water and wastewater systems for remote Central Australian sites in the future.

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