Financial feasibility of end-user designed rainwater harvesting and greywater reuse systems for high water use households

© 2017, The Author(s). Water availability pressures, competing end-uses and sewers at capacity are all drivers for change in urban water management. Rainwater harvesting (RWH) and greywater reuse (GWR) systems constitute alternatives to reduce drinking water usage and in the case of RWH, reduce roof runoff entering sewers. Despite the increasing popularity of installations in commercial buildings, RWH and GWR technologies at a household scale have proved less popular, across a range of global contexts. For systems designed from the top-down, this is often due to the lack of a favourable cost-benefit (where subsidies are unavailable), though few studies have focused on performing full capital and operational financial assessments, particularly in high water consumption households. Using a bottom-up design approach, based on a questionnaire survey with 35 households in a residential complex in Bucaramanga, Colombia, this article considers the initial financial feasibility of three RWH and GWR system configurations proposed for high water using households (equivalent to >203L per capita per day). A full capital and operational financial assessment was performed at a more detailed level for the most viable design using historic rainfall data. For the selected configuration (‘Alt 2’), the estimated potable water saving was 44% (equivalent to 131m3/year) with a rate of return on investment of 6.5% and an estimated payback period of 23years. As an initial end-user-driven design exercise, these results are promising and constitute a starting point for facilitating such approaches to urban water management at the household scale

Evaluation of Energy Efficiency Measures in High-rise Buildings from a Life Cycle Greenhouse Gas Emissions Perspective

Due to its significant contribution to greenhouse gas (GHG) emissions, the building industry is taking action to fight climate change, developing measures for reducing the operational emissions of buildings. However, some of these well-intentioned measures can result in higher embodied emissions. Under certain conditions, this increase in embodied emissions can more than offset the reductions achieved during the building operational phase. This thesis evaluates the effectiveness of five passive energy efficiency measures to reduce GHG emissions from a life cycle perspective for high-rise residential buildings in Toronto, Canada. Decreasing the window-to-wall ratio was found to be the most effective measure to reduce total GHG emissions. Increasing the continuous insulation on walls and roofs with GHG intensive materials can increase total emissions. The thesis also compares the embodied GHG emissions of curtain walls and window walls finding no practical difference in embodied GHG emissions between the options studied.M.A.S