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 Heterogeneous Photocatalytic Treatment for Reuse of a Hotel's Greywater

Reuse of greywater for non-potable purpose such as irrigation, toilet flushing and groundwater recharge has been evaluated and applied widespread after advanced treatment processes. Specifically advanced oxidation processes present alternative option to integrate with biological treatment as prior or post-treatment to remove recalcitrant organic matters of emerging concern in greywater. This study focuses on the efficiency assessment of heterogeneous photocatalysis (PC) for oxidative degradation of real greywater samples collected at a hotel in Antalya, Turkey, by means of dissolved organic carbon (DOC) and UV254 absorbance removals that correspond the mineralization and degradation rates, respectively. Increasing TiO2 dose from 0.1 to 1 g/L enhanced DOC removal rates. Reduction of suspended solids from greywater using 0.45 microfilters increased DOC removal from 27 to 35% during PC treatment

Is Gray Water the Key to Unlocking Water for Resource-Poor Areas of the Middle East, North Africa, and Other Arid Regions of the World?

Support for the use of treated gray water as an alternative water resource in the Middle East and North Africa is high, especially given the lack of religious restrictions against its use, but several obstacles have kept application of treated gray water near 1 % in some areas. The largest of obstacles include the cost of treatment and the ambiguity surrounding the health safety of gray water and treated gray water. This paper aims to provide an overview of current gray water practices globally, with specific focus on household-level gray water practices in the Middle East and North Africa region, and highlight the need for cost reduction strategies and epidemiological evidence on the use of household-level gray water and treated gray water. Such actions are likely to increase the application of treated gray water in water-deprived areas of the Middle East and North Africa