Water pollution

1. WATER POLLUTION

2. INTRODUCTION
• Water is the essential element that makes life on earth possible. Without water there
would be no life.
• Although 71% of the earth’s surface is covered by water only a tiny fraction of this
water is available to us as fresh water. About 97% of the total water available on earth
is found in oceans and is too salty for drinking or irrigation. The remaining 3% is fresh
water. Of this 2% is locked in ice caps or glaciers. Thus only 1% of the earth’s total
volume of water is easily available to us as soil moisture, groundwater, water vapour
and water in lakes, streams, rivers and wetlands.
• In some years, the commencement of the rains may be delayed considerably over
the entire country or a part of it. The rains may also terminate earlier than usual. They
may be heavier than usual over one part than over another. All these may cause local
floods or drought. However in India even areas that receive adequate rainfall during
the monsoon suffer from water shortages in the post monsoon period due to lack of
storage facilities.
• As freshwater becomes scarcer access to water resources will be a major factor in
determining the economic growth of several countries around the world.

4. SOURCES OF WATER POLLUTION
When the quality or composition of water changes
directly or indirectly as a result of natural processes or
man’s activities such that it becomes unfit for any
purpose it is said to be polluted.
• When a source of pollution can be readily identified
because it has a definite source and place where it
enters the water it is said to come from a point
source. Ex. Municipal and Industrial Discharge Pipes.
• When a source of pollution cannot be readily
identified, such as agricultural runoff, acid rain, etc.,
they are said to be non-point sources of pollution.

5. CAUSES OF WATER POLLUTION
• Mining activities: due to the exploitation of minerals when rain falls it sweeps the soil to
the source of water resulting in pollution.
• Disposal of untreated sewage (effluent) into the water bodies from various sources e.g.
industrial wastes or domestic wastes.
• Dumping of municipal solid waste from households into the nearby water bodies
• Oil spills from the leaking oil containers of pipes during the transportation of such raw
materials
• Washing out of fertilizers, insecticides, pesticides and agro-waste from the
agricultural fields can get into the water bodies through the surface run-off.
Sewage consists of wastewater discharged from residences and from commercial, institutional
and public facilities that exist in the locality. Sub-types of sewage are greywater (from sinks,
bathtubs, showers, dishwashers, and clothes washers) and blackwater (the water used to toilet
flushes, combined with the human waste that it flushes away).

6. • Volcanic eruption: flow of magma on the surface could lead to
water pollution because it can flow to the source of water.
• Acid rain on the water bodies can make the water acidic
• Leakage of radioactive waste stored under the water
• Surface runoffs from streets, improper discharge of lubricating oil
from machines or automobile crankcases and intentional oil
discharges that occur during the loading and unloading of tankers.
• Power plants heat water to convert it into steam, to drive the
turbines that generate electricity. For efficient functioning of the
steam turbines, the steam is condensed into water after it leaves the
turbines. This condensation is done by taking water from a water
body to absorb the heat. This heated water, which is at least 15oC
higher than the normal is discharged back into the water body. The
warm water not only decreases the solubility of oxygen but changes
the breeding cycles of various aquatic organisms.
CAUSES OF WATER POLLUTION

7. We can categorise water pollutants into four categories:
• Organic contaminants: Manure or sewage
• Inorganic contaminants: Mining, industrial or agricultural
chemicals
• Sediment of suspended matter: insoluble particles of soil and
other solids that become suspended in water
• Pathogens: caused by microorganisms
• Thermal Pollutants: change in temperature by human activities
• Radioactive pollutants

8. EFFECTS OF WATER POLLUTION
• Water Pollution causes various Diseases in live stocks, humans, and other
aquatic species. It causes typhoid, cholera, hepatitis and various other
diseases are caused by water pollution.
• Water pollution can destroy the entire ecosystem and its living organisms.
• Eutrophication is another harmful effect of Water pollution. Eutrophication
is due to Chemicals in a water body, encourage the growth of algae. In
eutrophication, algae form a layer on top of the water bodies pond or lake.
Eutrophication occurs in water bodies which are stable.
• Water Pollution disturbs the entire food chain . The food chain disturbance
starts when toxins and pollutants are consumed by species in the base of
the food chain and at each link in the food chain these chemicals which do
not pass out of the body are accumulated and increasingly concentrated
resulting in biomagnification of these harmful substances in the species on
the top of the food chain

9. Self purification of rivers
Stream Sanitization
Definition: The automatic purification of a
polluted water in due course is known as
self purification phenomenon.
Natural processes involved are:
1. Dilution and Dispersion
2. Sedimentation
3. Oxidation and Reduction

10. Physical forces
• Dilution and dispersion: When the putrescible organic matter
is discharged into a large volume of water contained in the
river or streams, it gets rapidly dispersed and diluted. This
diminishes the concentration of the organic matter and.
• Sedimentation: The settleable solids, if present in the effluent
will settle down into the bed of the river, near the outfall of the
effluent, thus helping in self purification.
• Sunlight: The sunlight has a bleaching and stabilizing effect of
bacteria. It also helps certain micro-organism to derive
energy from it, and convert themselves in food for other forms
of lives (protozoa and algae), thus absorbing carbon-dioxide
and releasing oxygen (photosynthesis). The evolution of
oxygen into the water in the presence of sunlight will help to
self-purify the water through oxidation.

11. Biochemical forces
• Oxidation: The oxidation of the organic matter present
in the effluent starts as soon as the effluent outfalls
into the river water containing dissolved oxygen. The
deficiency of oxygen so created will be filled up by the
atmospheric oxygen. The process of oxidation will
continue till the organic matter has been completely
oxidised.
• Reduction: The reduction occurs due to hydrolysis of
the organic matter settled at the bottom either
chemically or biologically. Anaerobic bacteria will help
in splitting the complex organic constituents of sewage
into liquids and gases, thus paving the way for their
ultimate stabilization by oxidation.

12. Factors affecting natural forces of purification
• Temperature
• Turbulence
• Hydrography i.e., velocity and surface
expanse of rivers
• Available dissolved oxygen
• Rate of reaeration
• Amount and type of organic matter present

13. • Temperature: At higher temperature the ability to hold
dissolved oxygen in water is less, while the rate of biological
and chemical activities of decomposing the organic matter is
high. This causes rapid depletion of DO, leading to anaerobic
conditions and the pollution when the pollution due
putrescible organic matter is heavy.
• Turbulence in the body of water helps to break the surface of
the stream and helps in rapid reaeration from the atmosphere.
Thus, it helps in maintaining the aerobic conditions in the
stream and keeps it clean. Too much of turbulence is however
not desirable as it scours the bottom sediments, thereby
increasing the turbidity and decreases the algal growth, which
is useful in reaeration of the stream.
• High velocity cause turbulence and rapid aeration of the
stream. Large surface expanse will also lead to better
aeration of the streams.
• The presence of algae contributes to the aeration of the
stream as a result of photosynthesis.
• The rate of reaeration is the rate at which DO deficiency is
replenished. The greater is the reaeration rate the quicker is
the self purification of the river as there will be very less
chances of development of anaerobic conditions in the stream

14. Physical Water Quality Parameters
• Colour
• pH
• Temperature
• Suspended solids

15. Chemical Water Quality Parameters
• Hardness
• COD
• BOD
• Dissolved solids
• Alkalinity
• Metals and heavy metals

16. Biological Properties
• Bacteria, virus and protozoa

17. GROUNDWATER POLLUTION
While groundwater is easy to deplete and pollute it gets renewed very slowly
and hence must be used judiciously. Groundwater flows are slow and not
turbulent hence the contaminants are not effectively diluted and dispersed as
compared to surface water. Moreover pumping groundwater and treating it is
very slow and costly. Hence it is extremely essential to prevent the pollution of
groundwater in the first place. Ground water is polluted due to:
• Urban run-off of untreated or poorly treated wastewater and garbage
• Industrial waste storage located above or near aquifers
• Agricultural practices such as the application of large amounts of fertilizers
and pesticides, animal feeding operations, etc. in the rural sector
• Leakage from underground storage tanks containing gasoline and other
hazardous substances
• Leachate from landfills
• Poorly designed and inadequately maintained septic tanks
• Mining wastes

18. THE STATE OF INDIA’S RIVERS
• India has always had a tradition of worshipping rivers. Most of the
rivers in India are named after gods, goddesses or saints.
• Urbanization, industrialization, excess withdrawal of water,
agricultural runoff, improper agricultural practices and various
religious and social practices all contribute to river pollution in India.
• Every single river in India be it the Ganga, Yamuna, Cauvery or the
Krishna have their own share of problems due to pollution. Waters
from the Ganga and the Yamuna are drawn for irrigation through the
network of canals as soon as these rivers reach the plains reducing
the amount of water that flows downstream. What flows in the river
is water from small nalas, and streams that carry with them sewage
and industrial effluents. The residual freshwater, is unable to dilute
the pollutants and the rivers turn into stinking sewers. Despite, data
from scientifically competent studies conducted by the Central
Pollution Control Board (CPCB), the Government has not been able
to tackle this issue.
Sewage and municipal effluents account for 75% of the pollution load in
rivers while the remaining 25% is from industrial effluents and non-point
pollution sources.

19. • In 1985, India launched the Ganga Action plan (GAP) the largest ever river
cleanup operation in the country. The plan has been criticized for,
overspending and slow progress. The GAP Phase II in 1991 included
cleaning operations for the tributaries of the Ganga, i.e.; the Yamuna, Gomti
and the Damodar. Thus the Yamuna Action Plan (YAP), Gomti Action Plan
and the Damodar Action plan were added.
• In 1995 the National River Conservation plan was launched. Under this all
the rivers in India were taken up for cleanup operations. In most of these
plans, attempts have been made to tap drains, divert sewage to sewage
treatment plants before letting out the sewage into the rivers.
• The biggest drawback of these river cleaning programs was that they failed
to pin responsibilities as to who would pay for running the treatment facilities
in the long run. With the power supply being erratic and these plants being
heavily dependent on power, most of these facilities lie underutilized.
• Moreover the problem of river pollution due to agricultural runoff has not
been addressed in these programs. NRCP is scheduled to be completed by
March 2005. The approved cost for the plan is Rs. 772.08 crores covering
18 rivers in 10 states including 46 towns. The cost is borne entirely by the
Central Government and the Ministry of Environment and Forests is the
nodal agency that co-ordinates and monitors the plan. Under this plan the
major activities include treating the pollution load from sewer systems of
towns and cities, setting up of sewage treatment plants, electric crematoria,
low cost sanitation facilities, riverfront development, afforestation and solid
waste management.

20. CONTROL MEASURES FOR PREVENTING
WATER POLLUTION
• While the foremost necessity is prevention, setting up effluent
treatment plants and treating waste through these can reduce the
pollution load in the recipient water. The treated effluent can be
reused for either gardening or cooling purposes wherever possible.
• A few years ago a new technology called the Root Zone Process
has been developed by Thermax. This system involves running
contaminated water through the root zones of specially designed
reed beds. The reeds, which are essentially wetland plants have the
capacity to absorb oxygen from the surrounding air through their
stomatal openings. The oxygen is pushed through the porous stem
of the reeds into the hollow roots where it enters the root zone and
creates conditions suitable for the growth of numerous bacteria and
fungi. These micro-organisms oxidize impurities in the wastewaters,
so that the water which finally comes out is clean.

21. • The first major solution in this context is conservation of soil. Soil
erosion can contribute to water pollution. So, if soil can be
conserved, we can prevent water pollution too. We can follow
measures such as planting more trees, managing erosion in a better
way, and use farming methods that are better for the soil.
• In the same vein it is also important to follow the right methods in
disposing toxic waste. For starters, we can use products that have
lesser amounts of volatile organic compounds in them. Even in
cases where toxic material like paints, cleaning supplies, and stain
removers are used, they need to be disposed off in the right way.
• It is also important to investigate oil leaks in one’s cars and
machines. It is said that leaked oil – even from cars and machines –
is one of the principal contributors to water pollution. Hence, it is
important to look at cars and machines, which run on oil, on a
regular basis, to check them for any possible oil leak. It is important
after work – especially in factories and production units where oil is
used, to clean up the wasted oil and either dispose it properly or
keep it for later use.

22. SOLUTION OF WATER POLLUTION IN INDIA
Following are some other ways in which this
problem can be addressed adequately:
• Cleaning up waterways and beaches
• Avoiding the usage of non-biodegradable
material like plastic
• Being more involved in various measures
pertaining to preventing water pollution.