Environmental Engineering Reference
In-Depth Information
Operation
and
Maintenance
Cost
Suitability
for
Community
Level
Suitability
for
Household
Level
Requirement
of
Chemicals
Requirement
of Skilled
Manpower
Energy
Require-
ments
Defluoridation
Technique
Ease of
Operation
Capital
Cost
Precipitation
Ion-exchange
Adsorption
Membrane
methods
Note:
Light gray, advantages; gray, limitations; dark gray, can be compromised.
FIGURE 17.1
General merits and demerits of various deluoridation techniques.
17.2 Fluorosis Control Options
The ultimate objective of any deluoridation technology is to control or mitigate the health
impacts of excessive luoride intake, i.e., luorosis. Although deluoridation of water has
been considered as the most effective option for luorosis mitigation, recent studies also
point out at the importance of other parameters, including luoride intake through food
as well as the remedial potential of nutritional supplements. There have been numerous
efforts to ind alternate water sources; however, for obvious reasons, these options are
region speciic. Brief description of various options for providing water with acceptable
luoride concentrations is discussed in the following sections.
17.2.1 Alternative Water Sources
An alternate water source option becomes attractive when deluoridation technology is not
effective or implemented ineffectively for some reason. A number of options are attempted
and practiced in different parts of the world. Depending on hydrogeological conditions
of a particular region, it could be possible to obtain a local safe water source by drawing
the water from different depths. Since leaching of luoride into groundwater is a localized
phenomenon, which depends on many and complex parameters, it is sometimes possible
to ind a sustainable new source of water. Regular monitoring of luoride concentration is,
however, needed because mixing of water from different aquifers with different luoride
concentrations cannot be ruled out. Transporting water from a distant source has also been
successfully practiced; however, the economic feasibility of this option is often dificult in
less developed countries. In such cases, initial high cost is compensated in long-lasting
beneits if other alternates are not effective. Mixing of high- and low-luoride-containing
waters to bring the luoride concentration within permissible levels can be an attractive
long-term solution, provided the low-luoride water source is available within reasonable
distance and that is of acceptable quality with respect to other water parameters. This has
been effectively implemented in some parts.
