Financial Viability of Implementing a Greywater Reuse System in the Life Sciences Centre on Dalhousie University’s Studley Campus

Abstract

The majority of Earth’s water supply is unsuitable for consumption, with only 2.5% classified as freshwater and 1.7% of that is trapped in glaciers, snowcaps and icecaps (Parece et al., 2013). Although Canada is a water-rich country, regional temperatures are warming due to climate change and our northern environment is experiencing milder winters and hotter summers (Government of Canada, 2024b-c). These changes will affect the annual natural runoffs and will have long-term impacts on Canada's access to renewable sources of freshwater (Government of Canada, 2024a). Abdelalim et al. (2015) found that resources used within an institutional setting have the cumulative environmental impact of a small town. Our study explores the physical and financial viability of implementing a greywater reuse system to flush toilets in the Life Sciences Centre (LSC) on Dalhousie University’s Studley Campus. Light greywater from bathroom sinks is a source of greywater that requires minimal treatment to be reused for toilet flushing, a process that unnecessarily uses high-quality drinking water (Olanrewaju & Ilemobade, 2015). To assess the feasibility, both quantitative calculations and qualitative interviews were conducted. During bathroom analysis, usage was monitored, assumptions were made to estimate greywater generation, and freshwater consumption for toilet flushing was measured. In addition, six Dalhousie experts with extensive knowledge of wastewater systems were interviewed. Their responses provided valuable insight and were coded to determine key takeaways. One set of male and female bathrooms in the common area of the LSC was used as the site for this case study, which revealed bathroom sinks generate approximately 39.9 L/hour of greywater, while toilets and urinals consumed around 275.53 L/hour of freshwater. This significant gap indicated the volume of greywater produced would be insufficient to meet flushing demands, rendering the system physically unfeasible. A cost-benefit analysis of economic feasibility supported these results, with annual water savings amounting to roughly $316.23, and over time, this would not be enough to profit or break even within the expected lifespan of a greywater reuse system. Qualitative analysis also reflected these complications, with only three subcodes for potential benefits emerging, while fourteen subcodes related to challenges and concerns. Although greywater reuse offers environmental benefits and supports sustainable resource management, our findings have indicated this proposed reuse method lacks the physical and financial feasibility required to be implemented in the Life Sciences Centre. As such, alternative water-saving strategies may present a more practical and viable option for Dalhousie University. Keywords: campus sustainability, cost-benefit analysis, feasibility, wastewater, water conservation, water management