Description

Grey water or silage is all the wastewater generated in households or office
buildings from streams without fecal contamination, all streams except for the
wastewater from toilets. Sources of grey water include sinks, showers, baths,
washing machines, or dishwashers. As greywater contains fewer paths. Opens than
domestic wastewater, it is generally safer to handle and easier to treat and reuse
onsite for toilet flushing, landscape or crop irrigation, and other non-potable uses.
The application of greywater reuse in urban water systems provides substantial
benefits for both the water supply sub-system by reducing the demand for fresh
clean water and for the wastewater subsystems by reducing the amount of
wastewater required to be conveyed and treated. Treated grey water has many
uses, for example, toilet flushing or irrigation.
Grey water usually contains some traces of excreta and is therefore not free of
pathogens. The excreta comes from washing the anal area in the bath and shower
or from the laundry (washing underwear and nappies). The quality of grey water
can deteriorate rapidly during storage because it is often warm and contains some
nutrients and organic matter as well as pathogens. Stored grey water also leads to
odor nuisances for the same reason.
In households with conventional flush toilets, grey water makes up about 65% of
the total wastewater produced by that household. It may be a good source of
water for reuse because there is a close relationship between the production of
grey water and the potential demand for toilet flushing water.