Systems For Water Desalination Water Treatment Process Dams Conserving Global Water Supply Community Fresh Water Supply

1. INFRASTRUCTURE PLANNING AND
MANAGEMT
ASSIGNMENT 05
SUBMITTED TO: SUBMITTED BY:
Prof. Dr. Subharjit Banerjee Aman Kudesia
Ar. Ashwani Rawat # 1900511300001
MURP (2019-20)
F.O.A.P., A.K.T.U.,
Lucknow
o Evaporation Systems For Water Desalination.
o Drinking Water Treatment Process.
o Dams – Benefits, Costs, River Driven Projects Of India.
o Conserving Global Water Supply.
o How To Increase Community Freshwater Reservoir.

2. 01. Evaporation Systems For Water Desalination
Of the desalination methods available, the two main ones are: distillation
followed by condensation and reverse osmosis. A simple, low-
cost method to desalinate sea water by distillation is used in some countries
where fuel is available.
Sections:
o Desalination Technologies
o Thermal Vapour Recompression
o Multiple Effect Distillation (MED)
o Mechanical Vapour Compression (MVC)
o Other Alternatives

3. Desalination Technologies
There are small desalination plants evaporating seawater or brackish well water. These plants
consume small amounts of electrical energy, which can be obtained by windmills, solar panels or
other renewable electrical energy sources.
The technologies used today in water desalination processes can be classified according to the
following main criteria:
o Phase change (in the water to be treated).
o Type of energy involved.
o Process employed.

4. Thermal Vapour Compression (TCV)
o This is one of the two technologies used This
consists of obtaining distilled water by the same
process as multiple effect distillation, but by using a
different source of thermal energy.
o These are thermal compressors (or thermo-
compressors), which consume medium pressure
steam from electricity generation plants (if it is a
dual plant, it is process vapor obtained expressly for
this purpose).
o They take part of the vapor produced in the last
stage at very low pressure, compress it and obtain
an intermediate vapor pressure comparable with
the previous ones suitable to contribute to the 1st
stage, which is the only one consuming energy in
the process.
o The yield from this type of plant is similar to those
from multiple effect distillation (MED) plants;
however, their desalination capacity can be much
greater by allowing greater adaptability for the
input from steam production plants.
o They are often considered to be the same process,
but here they will be treated individually as the
energy from the plant is consumed by different
equipment.

5. Multiple Effect Distillation (MED)
o The water to be treated passes through a set of evaporators in series.
o The steam from one cell is used to evaporate the water in the following, while the primary
energy input is to the first stage.
o These are intermediate size plants and are especially indicated when they can be combined
using residual heat from turbine or cogeneration installations
Multi-stage Flash Distillation (MSF)
The Water To Be Desalinated Is Heated At
Low Pressure, Which Causes Sudden,
Irreversible Evaporation. This Process Is
Repeated In Successive Stages Where The
Pressure Decreases According To Different
Conditions.
It Is Suitable For Waters Of A High Salinity
Or Those Of A Higher Temperature And
Greater Pollution. The Major Disadvantage
Of MSF Plants Is The High-energy
Consumption.
Currently, There Are Facilities Where
Electrical Energy Generation From Solar
Parks Is Combined With Drinking Water
Production From Flash Type Evaporation
Plants.

6. Mechanical Vapour Compression (MVC)
o Vacuum evaporators using mechanical
vapor compression (MVC) evaporate the
liquid, in this case salt water, on one side of
the exchange surface, and this is
compressed sufficiently to condense on the
other side and thus maintain the water
distillation cycle; saving losses from the
process and the elevation of the boiling
temperature of the salt water with respect
to pure.
o These small devices are much more reliable
and simple to operate than reverse osmosis
equipment and are virtually maintenance-
free, which makes them ideal for supplying
fresh water to small population centers,
remote areas or islands
o The specific consumption of these facilities
is lower than for other distillation
processes, with the equivalent electrical
consumption normally about 10 kWh/m3.
o The biggest limitation of this type of
technology is the maximum size of the
volumetric compressors used. Its maximum
capacity does not allow for high production
of desalinated water.

7. Other Alternatives
Another way to obtain potable water from the sea or brackish sources is via vacuum water
evaporators, which take advantage of the residual heat sources from cogeneration engine cooling
circuits. This increases the percentage energy recovery and reaches the minimum objectives to be
able to charge energy premiums sold to the network.
o Evaporation vs. filtration (osmosis) technologies
• Currently there are small evaporation plants to desalinate brine or brackish water sources, which
require small amounts of electrical energy that can be obtained from windmills, photovoltaic panels or
other forms of renewable energy.
• In evaporation processes for obtaining potable water from salt water, the energy consumption does not
depend on the salinity of the water treated; thus, the more saline the input water is the more
advantageous they are, from this point of view, with respect to reverse osmosis processes.
• The membrane technique associated with reverse osmosis, and comparable from the energetic point
of view with evaporation, is forced osmosis.
• This process produces desalinated water using a semipermeable membrane and a solution of an easily
separable compound; this significantly increases the osmotic pressure, which forces the flow through
the membrane.
• It is carried out at very low pressures and at room temperature, leading to very low energy
consumption.
• To conclude, evaporation technologies are very effective, regarding low energy consumption, in
providing drinking water from salt water, irrespective of the input water salinity, and are comparable
only with forced osmosis (a filtration technology), whose energy consumption is also very low.

8. 02. Drinking Water Treatment Process
Community Water Treatment
Drinking water sources are subject to contamination and require
appropriate treatment to remove disease-causing agents. Public
drinking water systems use various methods of water treatment
to provide safe drinking water for their communities. Today, the
most common steps in water treatment used by community
water systems (mainly surface water treatment) include:
o Coagulation and Flocculation: Coagulation and flocculation are often
the first steps in water treatment. Chemicals with a positive charge are
added to the water. The positive charge of these chemicals neutralizes
the negative charge of dirt and other dissolved particles in the water.
When this occurs, the particles bind with the chemicals and form
larger particles, called floc.
o Sedimentation: During sedimentation, floc settles to the bottom of the
water supply, due to its weight. This settling process is called
sedimentation.
o Filtration: Once the floc has settled to the bottom of the water supply,
the clear water on top will pass through filters of varying compositions
(sand, gravel, and charcoal) and pore sizes, in order to remove
dissolved particles, such as dust, parasites, bacteria, viruses, and
chemicals.
o Disinfection: After the water has been filtered, a disinfectant (for
example, chlorine, chloramine) may be added in order to kill any
remaining parasites, bacteria, and viruses, and to protect the water
from germs when it is piped to homes and businesses.

9. Household Water Treatment
Even though EPA regulates and sets standards for public drinking water, many Americans use a home
water treatment unit to:
o Remove specific contaminants
o Take extra precautions because a household member has a compromised immune system
o Improve the taste of drinking water
Household water treatment systems are composed of two categories: point-of-use and point-of-entry
(NSF). Point-of-entry systems are typically installed after the water meter and treat most of the water
entering a residence. Point-of-use systems are systems that treat water in batches and deliver water to
a tap, such as a kitchen or bathroom sink or an auxiliary faucet mounted next to a tap.
The most common types of household water treatment systems consist of:
o Filtration Systems: A water filter is a device which removes impurities from water by means of a physical barrier,
chemical, and/or biological process.
o Water Softeners: A water softener is a device that reduces the hardness of the water. A water softener typically
uses sodium or potassium ions to replace calcium and magnesium ions, the ions that create “hardness.”
o Distillation Systems: Distillation is a process in which impure water is boiled and the steam is collected and
condensed in a separate container, leaving many of the solid contaminants behind.
o Disinfection: Disinfection is a physical or chemical process in which pathogenic microorganisms are deactivated or
killed. Examples of chemical disinfectants are chlorine, chlorine dioxide, and ozone. Examples of physical
disinfectants include ultraviolet light, electronic radiation, and heat.

10. Benefits Of Dams
Dams provide a range of economic, environmental, and social
benefits, including recreation, flood control, water supply,
hydroelectric power, waste management, river navigation, and
wildlife habitat.
o Recreation
Dams provide prime recreational facilities throughout the United
States. Boating, skiing, camping, picnic areas, and boat launch
facilities are all supported by dams.
o Flood Control
In addition to helping farmers, dams help prevent the loss of life and
property caused by flooding. Flood control dams impound
floodwaters and then either release them under control to the river
below the dam or store or divert the water for other uses. For
centuries, people have built dams to help control devastating floods.
o Water Storage (Fire & Farm Ponds)
Dams create reservoirs throughout the United States that supply
water for many uses, including industrial, municipal, and agricultural.
o Irrigation
Ten percent of American cropland is irrigated using water stored
behind dams. Thousands of jobs are tied to producing crops grown
with irrigated water.
03. DAMS

11. Costs Of Dams
o A large dam is defined by the dam
industry as one higher than 15
meters (taller than a four-story
building). There are more than
57,000 large dams worldwide. There
are more than 300 major dams -
giants which meet one of a number
of criteria on height (at least 150
meters), dam volume and reservoir
volume.
o China has over 23,000 large dams.
The US is the second most dammed
country with some 9,200 large dams,
followed by India, Japan, and Brazil.
o Between 40 and 80 million, the
majority of them in China and India.
o Six things to consider:
• Cost And Time Overruns
• Involuntary Displacement
• Decision-making Processes
• Growing Opposition Against
NHPC Projects
• Environmental Impacts
• The Impacts Of Climate Change
The author Arundhati Roy, winner of
the Booker Prize, commented in the
summer of 2004:
“The Madhya Pradesh government and
its partner, the NHPC, have rampaged
through the region with a callousness
that would shock even a seasoned
cynic.… A crime of this proportion is not
going to be forgotten so easily. If it goes
unpunished, it cannot but damage
India's image as a benign destination for
International Finance: thousands of
people, evicted from their homes with
nowhere to go.”

12. o This River-Linking project is a large-scale civil engineering
project.
o The project aims to link rivers via a network of canals and
reservoirs all across India.
o Living in a democratic setup, we must not only talk about
equality on the basis of caste, colour, rights, creed and sex,
but peace in our nation will reside when all its citizens have an
equal access to its diverse resources.
o The National Perspective Plan (NPP) is responsible for focusing
on this project of 150 million acre feet (MAF), along with 185
billion cubic metres of shortage of water. This will involve
building of inter-links.
o The system that will be created for storage purposes will lead
to the addition of approximately 170 million acre feet capacity
of water. This stored water will then be used for beneficial
purposes in various states.
o Construction of large reservoirs will lead to the generation of
34 gigawatt of hydroelectric power.
o Around 30 canals are proposed to be built, between 50 to 100
metres in width, and stretching up to 15,000 km.
Water Diversion Projects In India
Water is scarce in nature, it must be used judiciously. Nothing could go right without water on this Earth.
It is a vital resource responsible for the existence of all the living beings. We call ourselves humans, and
happily believe in the fact that we are ‘rational creatures’ who are continuously busy, depleting the very
existence of water, which if once drained will take millions of years to renew.

13. Who Will Manage This Project And How Will It Progress Strategically:
This inter-linking project is completely managed and controlled by India’s National Water
Development Agency (NWDA), which operates under the Union Ministry of Water Resources.
The project is bifurcated into 3 parts:
o A northern Himalayan Rivers inter-link component.
o A southern Peninsular component.
o An intrastate rivers linking component.
So far, NWDA has gone through the project details and reports have been prepared on 14 inter-link
projects of the Himalayan component, whereas 16 inter-link projects for the southern Peninsular
component and 37 of intrastate river linking project reports have been completed.
Some major River-Linking projects include:
o Damanganga
o Par-Tapi
o Manas-Sankosh-Teesta-Ganga Link
o Mahanadi-Godavari Link Project
o Ken – Betwa Link Project
o Intra-State Links
List Of Benefits Involved:
o This will lead to addition of 35 million hectares for irrigation.
o It will increase the irrigation potential from 140 million hectares to around 175 million hectares.
o These projects will lead to the generation of 34,000 megawatt power.
o Other than the ones stated above, major benefits will also include navigation, water supply, salinity, flood
control and pollution control.

14. We all need water to survive — so when water suffers, people suffer too. Just consider these
facts:
o 780 million people don’t have access to clean water and almost 2.5 billion lack adequate
sanitation. These numbers may double over the next 30 years as human populations explode.
o About 6,000 children die each day from water-borne illnesses — a death toll equivalent to 10 jumbo jets
going down every single day.
o In the U.S., nearly 40% of all rivers and streams are too polluted for fishing and swimming due to sewage,
agricultural runoff and precipitation of industrial airborne pollutants. In China, seven out of 10 major
rivers are severely polluted.
o In countries like Colombia and Indonesia, flooding is increasing — a shift partially attributed to climate
change.
o In other places like California, East Africa and Australia, droughts are taking a horrible toll on agriculture —
which soaks up 70% of freshwater use — and everyday life.
o The collapse of freshwater-dependent species like Chinook salmon in the western U.S. has impacted the
livelihoods of numerous commercial and subsistence fishermen worldwide.
04. Conserving Global Water Supply
Ways To Overcome Global Water Supply Issues:
o Large-scale Reservoirs And Inter-basin Transfers.
o Cloud Seeding.
o Desalination.
o Agricultural Water Conservation.
o Urban Water Conservation.
o Off-stream Water Banking And Reserves.

15. Urban
In urban and rural-domestic sectors
elsewhere, notably the United States,
conservation measures are most effective
when they have broad public support.
Important voluntary domestic water
conservation measures include the
following:
o Limiting toilet flushing.
o Adopting water-saving plumbing fixtures,
such as toilets and shower heads.
o Adopting water-efficient appliances
(notably washing machines).
o Limiting outdoor uses of water, as by
watering lawns and gardens during the
evening and early morning, and washing
cars on lawns and without using a hose.
o Adopting water-saving practices in
commerce, such as providing water on
request only in restaurants and
encouraging multiday use of towels and
linens in hotels.
o Repairing household leaks.
o Limiting use of garbage disposal units.

16. 05. How To Increase Community
Freshwater Reservoir
The technologies or changes in behavior which show the most promise for addressing water
shortages over the next 10 years:
o Educate To Change Consumption And Lifestyles
o Invent New Water Conservation Technologies
o Recycle Wastewater
o Improve Irrigation And Agricultural Practices
o Appropriately Price Water
o Develop Energy Efficient Desalination Plants
o Improve Water Catchment And Harvesting
o Look To Community-based Governance And Partnerships
o Develop And Enact Better Policies And Regulations
o Holistically Manage Ecosystems
o Improve Distribution Infrastructure
o Shrink Corporate Water Footprints
o Build International Frameworks And Institutional Cooperation
o Address Pollution
o Public Common Resources/Equitable Access
o R&D/Innovation
o Water Projects In Developing Countries/Transfer Of Technology
o Climate Change Mitigation
o Population Growth Control

17. o Educate To Change Consumption And Lifestyles: Some regions led by India, Australia and the Southwest U.S., are
already facing the freshwater crisis. The most critical task is making sure the problem is much better understood
worldwide.
o Invent New Water Conservation Technologies: In areas where aquifers are drying up and rainwater is increasingly
unpredictable, innovation is needed. But as we attempt to cope with freshwater scarcity and develop
conservation technologies, energy consumption is an important consideration.
o Recycle Wastewater: In March, World Water Day panelists urged a new mindset for wastewater treatment. Some
countries, like Singapore, are trying to recycle to cut water imports and become more self-sufficient. The rich
East Asian republic is a leader in developing advanced technology that cleanses wastewater for other uses,
including drinking.
o Improve Irrigation And Agricultural Practices: Some 70 percent of the world’s freshwater is used for agriculture.
Improving irrigation can help close supply and demand gaps. In certain cases profligate irrigation practices meant
for an earlier era has weakened the ability of farmers to provide food and fiber to a growing world.
o Appropriately Price Water: Water pricing and rights go hand in hand, with consumers questioning the benefit of
higher prices.
o Develop Energy Efficient Desalination Plants: Desalination has been an energy-intensive solution to water scarcity.
Saudi Arabia could be fostering a new kind of desalination with its recent announcement to use solar-powered
plants. Britain has taken a different approach with small-scale facilities for agriculture.
o Improve Water Catchment And Harvesting: Water catchment systems are essential for areas with no other
reliable water sources. Pakistan and India—two countries that contend with some of the worst effects of climate
change—are overhauling rainwater harvesting systems. These efforts provide independent control of water
resources.
o Improve Distribution Infrastructure: Poor infrastructure is devastating to health and the economy. It wastes
resources, adds costs, diminishes the quality of life, and allows preventable water-borne diseases to spread
among vulnerable populations, especially children.