Environmental Engineering Reference
In-Depth Information
Table 6.4
How Melbourne households use their 220 KL/year
Area of water use
% of household use
Garden
35 %
Bathroom
26 %
Toilet
19 %
Laundry
15 %
Kitchen
5 %
Source: Water Resources Strategy Committee for the Melbourne Area,
(2002),
21st century Melbourne: a WaterSmart City. Final report.
Demand management has already led to a significant reduction from
some 340 KL a year to the present 220 KL/yr for household water use. This
has been achieved by an increase in people living in apartment buildings,
dual flush toilets, user-pay pricing, by other water savings and by public edu-
cation. Further reductions may be more difficult to achieve and will involve
changing the way people use water in their gardens.
Table 6.4 shows typical patterns of water use in Melbourne households.
It is apparent that over half of the water used in these households is for flush-
ing toilets and watering gardens. This opens up the question as to why
potable water is used for such purposes. Urban communities must be
encouraged to examine recycling options to replace this potable water with
recycled water. There is also scope for water saving, through garden mulch-
ing and the use of low-flow showerheads.
Water recycling in Australia has been gaining some momentum over the
last decade, with the aim of reducing the environmental impacts of wastewa-
ter discharge to streams and coastal areas. There is political pressure to ban
ocean outfalls and to make more use of recycled water. This has mainly led to
the development of irrigation schemes to use recycled waters for agricultural
purposes.
The emerging recycling agenda is, however, to use recycled water to take
pressure off the scarce potable water resources by substituting recycled water
for potable water. Table 6.5 lists a number of recycling options that are being
explored.
We need to develop improved tools to aid decision making in this area.
How do we trade-off the impacts on coastal seagrass beds from ocean disposal
with the greenhouse gas production from sophisticated wastewater treatment?
How do we escape from the sort of economic lunacy where recycled water
