Environmental Engineering Reference
In-Depth Information
Atmospheric Water
Clouds
Clouds
Evapotranspiration
(from plants and
inland waters)
Precipitation
Transpiration
Foliage
Hills
Hills
River
Evaporation
Hills
Lake
Estuary
Ocean
Figure 2.2
Water cycle.
to a treatment plant for processing prior to disposal. Current process-
ing technologies provide only partial recovery of the original water qual-
ity. The upstream community (the first water user, shown in
Figure 2.3
) is
able to achieve additional quality improvement by dilution into a surface
water body and natural purification; however, as shown in the figure, the
next community downstream is likely to withdraw the water for a drinking
water supply before complete restoration. This practice is intensified and fur-
ther complicated as existing communities continue to grow and new com-
munities spring up along the same watercourse. Obviously, increases in the
number of users bring additional need for increased quantities of water. This
withdrawal and return process by successive communities in a river basin
results in
indirect water reuse
.
