Abstract:The water industry is becoming increasingly aware of the risks associated with urban supplies not meeting demands by 2050. Greywater (GW) recycling for non-potable uses (e.g., urinal and toilet flushing) provides an urban water management strategy to help alleviate this risk by reducing main water demands. This paper proposes an innovative cross connected system that collects GW from residential buildings and recycles it for toilet/urinal flushing in both residential and office buildings. The capital cost (CAPEX), operational cost (OPEX) and water saving potential are calculated for individual and shared residential and office buildings in an urban mixed-use regeneration area in the UK, assuming two different treatment processes; a membrane bioreactor (MBR) and a vertical flow constructed wetland (VFCW). The Net Present Value (NPV) method was used to compare the financial performance of each considered scenario, from where it was found that a shared GW recycling system (MBR) was the most economically viable option. The sensitivity of this financial model was assessed, considering four parameters (i.e., water supply and sewerage charges, discount rate(s), service life and improved technological efficiency, e.g., low flush toilets, low shower heads, etc.), from where it was found that shared GW systems performed best in the long-term. OPEN ACCESSSustainability 2013, 5 2888
Urbanisation in the twenty-first century is accompanied by higher water demands per unit area of available space.The ability of water providers to meet these demands long term will require sustainable innovations in terms of water supply. Previous research by the authors has shown that urban mixed-use systems that share greywater (GW) between high-rise domestic dwellings (where GW production exceeds non-potable demands) and high-rise offices (where non-potable demands exceed GW production) could overcome these difficulties. This paper explores the carbon costs (embodied and operational) of such an urban arrangement by investigating the influence of membrane bioreactors (MBRs), constructed wetlands (CWs), building heights, floor plate areas and cross-connection distances.Five water supply scenarios are considered: scenario 1 (conventional mains treated offsite); scenarios 2a and 2b (individual GW treatment via CW/MBR); scenarios 3a and 3b (shared GW treatment via CW/MBR). Over a 15-year period it is shown that shared CW treatment had the lowest carbon dioxide emissions, saving up to 11% compared with conventional mains, whereas a shared MBR increased carbon dioxide emissions by up to 27%. Furthermore, most carbon dioxide savings occur when the ratio (height or floor area) of office building to residential building is 2:3.
Stress on water resources in some areas is reaching critical levels due to population growth, rapid urbanization, economic development, climate change, and an ageing infrastructure. Greywater reuse has been explored as a more sustainable water resource management option to displace demand for fresh water, largely for residential use on a household or building level. However, the infrastructure needed and the disinfectant required for greywater systems make it difficult to see these systems as environmentally friendly and cost-effective, especially for individual households. The research reported herein tests the hypothesis that greywater reuse shared amongst users in neighbouring residential, office and commercial buildings may improve the feasibility of, and hence make more sustainable, greywater recycling as part of urban water management. The local area symbiosis scheme is designed in three stages: first, calculating a balance between greywater supply and demand in the area based on class of use (residential, office, or other); second, estimate sharing (local recycling) potentials based on the quantities available and requirements for use; and finally, estimating the sustainability of the proposed system by considering the technologies and infrastructure required for implementation.
Greywater (GW) recycling for non-potable uses such as toilet flushing is a management strategy to meet urban water demand with substantial water saving. This paper proposes a system that collects GW from residential buildings and recycles it for toilet flushing in both residential and office buildings. The total cost and water saving of standard sanitation technology were compared with 5 other options requiring less or no potable water use in toilets. Scenarios compare: no GW, individual GW, and shared GW systems with and without low-flush appliances. Typical residential and office buildings in urban mixed-use regeneration areas in the UK were used for these analyses. The results implied that constructed wetland treatment technology with standard appliances is more economically OPEN ACCESS and environmentally viable than other scenarios. By increasing the water and wastewater price, shared GW systems with and without low-flush appliances were viable options within highly water efficient domestic and office buildings.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.