Local area greywater symbiosis approach to a more sustainable urban water management

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.