Environmental Engineering Reference
In-Depth Information
22.4.3 Power Availability
Power shortage is one of the biggest challenges to overcome in developing countries.
Nonurban areas in almost all parts of India have regular power outages that can last for
several hours. During dry seasons, particularly at the peak summer times, power out-
ages can last for >12 h. Because of rolling brownouts, the time of a power outage and its
duration can be unpredictable. WHCs generally have peak demand periods in the morn-
ing when people collect water before they rush off to work and then again in late after-
noon/early evening time when children return from school or workers return from work.
Typically, these are the periods when power outages occur and compromise the ability to
purify water. The puriication process has to be carried out around the power outages, and
enough storage capacity needs to be provided to meet the demands during peak periods.
This adds a layer of complexity in the plant operation and increases the cost of operation
when operators have to be called in at odd hours. WaterHealth designs its systems with
provision of adequate overhead storage capacity so that clean water is available during
power outages and can be easily dispensed using gravity feed during these times.
It will be beneicial to have water treatment technologies that either do not require
power for operation or require very little power so that it can be operated using alternate
sources of energy. The puriication process has to be continuous and automated so that
water can be processed whenever power is available and does not require the presence of
an operator.
22.5 Application of Nanotechnology
In its efforts to provide clean water at an affordable cost, WaterHealth is constantly look-
ing for new technologies that can be incorporated into its design that help to reduce the
cost of installation and operation while improving their effectiveness in treating water for
a wide range of contaminants. Advances in nanotechnology in the water treatment sector
are showing considerable promise. While the technologies developed need to address the
challenges faced in these regions, they also need to address the three primary areas of
interest:
1. Water treatment
2. Disinfection
3. Real-time remote monitoring
Generally, the regions in Asia, Africa, and Central and South America where the major-
ity of the people not having access to clean water reside, these are the very same regions
where there is a shortage of freshwater availability. Treatment methods using reverse
osmosis for brackish water, for instance, particularly in small systems, waste a large frac-
tion of water and consume a high level of energy. Developments in nanotechnology have
the potential of improving these treatment methods or coming up with a new treatment
method that can signiicantly cut down water wastage and energy consumption. Ideally,
the new methods need to be such that they consume no power, other than the pumping
energy, as in the case of high surface area adsorbents. If the methods do need to utilize
power, they need to be low-energy-consuming technologies such as enhanced surface
