Environmental Engineering Reference
In-Depth Information
17.2.1.1 Dual Water Sources
If there are different sources available with both high and low luoride levels in the same
region or community, stress on safe water sources in such cases can be reduced by dilut-
ing the high-luoride water with low-luoride water so as to bring the concentration within
permissible limits. Another approach to conserve the safe water is by providing high- and
low-luoride water separately, and restricting the use of low-luoride water only for drink-
ing and cooking purposes. This is important considering the fact that the adverse health
impact of luoride is only through water ingestion and also that a small fraction of total
water use per capita is usually used for drinking and cooking. Besides almost double cost
implications, the success of both dilution and dual water supply schemes depends largely
on active community awareness and participation. The use of different water sources for
different purposes may also be aggravated by socioeconomic factors such as longer dis-
tances and reservations in sharing water sources with users from other neighborhoods.
Awareness alone is sometimes not enough to change practices, especially because the
health impacts of luoride becomes visible only after prolonged consumption of high-
luoride water.
17.2.1.2 Rainwater Harvesting
This approach is more relevant to tropical countries like India that receive reasonable
rainfall in most of the affected areas. Rainwater harvesting could be useful for luoride
control in two ways. This could be an alternate source of water, while the water collected
through rainwater can be used for dilution of high-luoride water. Harvested surface water
runoff can also be effectively used to recharge high-luoride groundwater sources. There
are cost issues involved as well as implementation of such options in several habitations.
Increasing water scarcity, however, makes rainwater harvesting a potential option, while
advantages of water quality add to the beneit of this option if water collection and storage
is done properly.
17.2.2 Artificial Recharge for Groundwater Fluoride Dilution
Artiicial recharge is an
in situ
method that dilutes the concentration of groundwater luo-
ride in a particular aquifer. Construction of check dams in some parts of India has been
demonstrated to reduce luoride concentration in groundwater. Rainwater recharge can
also be adopted using percolation tanks and recharge pits with appropriate site selections.
Detailed hydrogeological investigations are required to make the artiicial recharge more
effective and cost-effective. Recharge using rainwater after iltration through the existing
wells in the vicinity can also be cost-effective and used to improve the groundwater qual-
ity. As the users are not involved in luoride remediation technology through artiicial
recharge, this presents a potential option and is being explored. An additional advantage
with artiicial recharge is an improved water source, which is often required in most of
the areas.
17.2.3 Integrated Fluorosis Mitigation
Owing to the lowering of groundwater in many parts of India, there are signiicant risks of
increased bacteriological and chemical contamination mainly due to arsenic, luoride, and
nitrate. Therefore, to mitigate these contaminants, there is a need for a “holistic” health
