Alternative non-potable water use: Design, complexities, and opportunities

Alternative water sources such as brackish water or wastewater have become increasingly investigated for non-potable applications. However, choosing the most appropriate reuse scheme is complex due to the diversity of potential sources, requirements of non-potable applications, quality dynamics, and range of treatment technology capabilities. Additionally, the resulting social, economic, and environmental considerations can further complicate the decision-making process. Therefore, the aim of this research is to evaluate the complexities and opportunities for alternative water use as well as the methods of treatment which can connect sources and end uses. Through a critical review of the existing literature, it was found that alternative water use is primarily focused on municipal source and domestic end uses, even though their high human-exposure potential can pose a large risk. While treatment methods can help remove these harmful contaminants, the impacts of these technologies to the environment are not always clear. Therefore, a unique hybrid-modelling framework was developed for the purpose of evaluating technologies on a systems-level bases. The performance of these configurations were then compared on the basis of technical, economic, and environmental indicators. Due to the large number of results and the variance in indicator performance, a decision support tool was generated to assess these treatment configurations and compare them to other alternative sourcing methods (e.g. offsite water exploitation and transport). Throughout this research, it was noted that the focus of alternative water sourcing is almost exclusively from the perspective of product water feasibility. However, this can limit options for brine disposal or reuse and can lead to environmental impacts. A small exercise was pursued which visualized that indeed approaching water reuse from a bine requirement perspective had the potential to reduce economic and environmental impacts while also improving the range of possibilities for product water use. Therefore, it is recommended that future research reframe alternative water use to meet brine requirements first and then match the product water with potential cross-sectoral applications