Using recycled water for non-potable, urban uses: a review with particular reference to toilet flushing

Abstract

This paper summarises the current non-potable, urban use of reclaimed water with particular reference to toilet flushing. It compares water quality standards for reclaimed water, the volumes of water required for toilet flushing and the qualities of greywater and domestic sewage that have previously been used for reuse. Worldwide examples of reuse schemes are presented with particular detail to two key European sites where greywater has been used for toilet flushing, the Millennium Dome in the UK and a residential block of flats in Annecy, France. It was demonstrated that the interest in water reuse is growing steadily, not only in acknowledged water deficient areas, but also in countries which have not historically appeared to have a water supply problem. The latter include Northern European States such as Belgium, France, the UK and Germany, as well as in tourist coastal areas and islands. This situation affords great opportunities for the creation of urban water recycling schemes.

Rainwater Harvesting Typologies for UK Houses: A Multi Criteria Analysis of System Configurations

“…The UK has seen many developments and innovations in RWH design configurations, both within the RWH industry and within the academic research community [28][29][30][31][32]. The identification of details of these systems form the basis of Step 2.…”

Shared Urban Greywater Recycling Systems: Water Resource Savings and Economic Investment

“…Filters are included to remove the solid particles, such as hair and skin from the raw greywater, before it enters the treatment systems, either MBR or VFCW; MBR consists of a compact unit, which combines activated sludge treatment for the removal of biodegradable pollutants and a membrane for solid/liquid separation [49]. MBR is commonly used in large buildings, such as multi-storey buildings [50][51][52], student accommodation [6], stadiums [50] and communal residential buildings [27]. GW treatment facilities are fed by gravity and pumping is only required for redistribution of treated GW.…”

“…Not least because toilet flushing in a typical home accounts for approximately 30% of home water use and can reach over 60% in offices [26]. The high volume of GW generation in domestic properties, which accounts for approximately 50 to 70% of daily water outflow, is usually greater than the requirement for GW use (i.e., toilet flushing which requires 20 to 36% water inflow) [27] In other words, there would be a substantial excess of GW remaining (up to 50% of the GW produced) once toilet flushing demands are met through GW supplies. In contrast, the GW produced in commercial, retail and other non-residential buildings, which accounts for approximately 21% of water outflow (from hand basins alone), is substantially less than the requirement for GW use (i.e., toilet flushing, which requires 43 to 65% water inflow).…”

Assessment of Grey Water Disposal and Different Treatment Options for Domiz Camp in Duhok City

“…For example, SBR (Hernández Leal et al, 2010;Shin et al, 1998), MBR (Lesjean & Gnirss, 2006;Merz et al, 2007), RBC (Eriksson et al, 2007;Friedler et al, 2005;Nolde, 2000), and CWs (Gross et al, 2007;Li et al, 2004). The MBR technology can be considered as an attractive application for grey water reuse, specifically in urban domestic houses due to high organic loading rate, excellent removal efficiency, stable effluent quality, low sludge production and small footprint (Lazarova et al, 2003). On the other hand, MBR is not the suitable treatment option for the current study because it require high investment and operational cost as well as advanced technical support (Lesjean & Gnirss, 2006;Merz et al, 2007;Paris & Schlapp, 2010;Winward et al, 2008).…”