chemicals by setting allowable
concentration limits in the
effluent. “If we consider that
100% of the effluent can be
recycled, if done properly, there
is no doubt that through this
we are providing large banks
of water, which previously may
not have been considered as
‘safe’ for the environment or
the community.”
Haycock points out that
humans consume two to four
litres of water a day, with the
rest of water usage going
to wastewater. Much of this
is treatable.
Water treatment does,
however, come with a price tag,
albeit cheaper than desalinated
water. Haycock says it requires
approximately USD760 000 for
a small industrial plant and in
excess of USD38-million in the
municipal space.
But ultimately, can there be
a price tag on human life, one
must ask? u
Contributors: DWA, Veolia,
Talbot & Talbot, and SewTreat
Table 1: Water reuse terminology
Term Definition
Water reuse Utilisation of treated or untreated wastewater for a process other than the one that
generated it, i.e. it involves a change of user. For instance, the reuse of municipal
wastewater for agricultural irrigation.
Water recycling Utilisation of treated or untreated wastewater for the same process that generated it, i.e. it
does not involve a change of user. For instance, recycling the effluents in a pulp and paper
mill.
Direct reuse Reuse of treated or untreated wastewater by directly transferring it from the site where it
is produced to a different/separate facility for the next use.
First water use Water coming from a freshwater source receiving no identifiable upstream
wastewater discharges.
Indirect reuse Reuse of treated or untreated wastewater after it has been discharged into a natural
surface water or groundwater body, from which water is taken for further use.
Intentional or
planned reuse Use of treated or untreated wastewater as part of a planned project. It is always
performed intentionally, consciously, and using reclaimed water for a specific user.
Unplanned or
incidental reuse Subsequent use of treated or untreated wastewater after it has been discharged into a
surface water or groundwater body from which water is taken for drinking purposes or
another use. Initially, it always occurs as a subconscious activity; with time, it might occur
consciously but not as part of a planned project in which wastewater is properly treated
and water quality monitored for the specific water use purpose.
Reclaimed water Wastewater that has been treated to a level that is suitable for sustainable and safe reuse.
Return flows Treated and/or untreated wastewater that is discharged to a natural surface water or
groundwater body after use.
Wastewater Water derived from any of a number of uses of water and typically containing residual
pollutants associated with the use of the water.
Grey water Wastewater derived from the domestic and household use of water for washing, laundry,
cleaning, food preparation etc. Grey water does not contain faecal matter.
Black water Wastewater containing faecal matter and urine associated with water use in toilets
and urinals.
Source: National Water Resource Strategy, Annexure D (2011)