What Are the Main Options for Applying the Multiple-Use Water Services Paradigm? - Rethinking Infrastructure Design for Multi-Use Water Services - page 27

Fig. 1 The main options for multiple-use water services paradigm

can be treated on-site. The term ' reused ' water is often used similarly with ' recy-

cling water.

Residential wastewater, based on the source and level of contamination can be
further classi

' water or ' reclaimed '

ed as black (highly polluted) and grey. Black water, usually referred
to as wastewater, is highly contaminated water coming from toilets and urinals.
Grey water, on the other hand, is less polluted water discharged from sinks, showers
and bathtubs, washing machines and drinking fountains. When reusing grey water,
water discharged from kitchen sinks and dishwashers is generally excluded due to
higher levels of contamination coming from food residues and animal products.
MUS mainly focuses on the on-site use of reclaimed grey water used for multiple
non-potable purposes such as indoor and outdoor plant irrigation, including green
roofs and walls, and toilet flushing.

2.1 What Are the Main Components and Costs Related
to Grey Water Reuse?

Grey water reuse systems can vary signi cantly from simple, low-cost appliances

that harvest grey water and convey it for direct use, e.g. in toilets and gardens, to
composite systems integrating specialised treatment processes.
Cost and energy required can also vary, mainly increasing as more and better
treatment is involved. Grey water reuse systems are more suitable for new-built
developments, as retro tting existing systems can be more expensive, but they can

be incorporated while renovation and plumbing replacement activities occur
(CGBC 2011 ).