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Water Pollution
1. Submitted To: Dr. Shrabanti Dev
Assistant Professor
Pharmacy Discipline
Khulna University, Khulna.
Submitted By: 151115
151116
151117
151118
151119
2.
3. Water
The importance of water for sustenance of life cannot be
overemphasized. Whether it is in use of running water in our homes,
rearing cattle and growing crops in our farms, or the increased uses in
industry, remain immeasurable. It is important therefore, to not that
depletion of this commodity either through contamination, or careless
use results in serious consequences.
71% from earth surface.
97% salt water (sea)
3% fresh water
87% ice and glaciers, underground, air.
13% surface water (0.4% total water).
4. 70% total human body wt.
30 – 40% bone mass.
Body functions:
Absorption of oxygen at alveoli.
Control of body temperature.
Blood component.
Digestion in kidneys and intestine.
Alteration of 10% body content – health problem.
Alteration of 20% body content – death.
5.
6. Water Pollution!
Water is considered polluted if some substances or condition is present to such a
degree that the water cannot be used for a specific purpose. Water pollution is
intended as water quality degradation caused by the introduction of substances
that alter its physicochemical characteristics and impede its normal use. These
substances having either a solid, liquid or gaseous origin have different effects
according to their amount and potential danger and fragility of the environments
where they are released. The three main types of pollution are: Land Pollution, Air
Pollution and Water Pollution.
Both for the purpose of this assignment, emphasis are on water pollution and
control.
7. Water Pollution Parameters
Water may be called polluted when the following parameters stated
below reach beyond a specified concentration in water.
i) Physical parameters: Color, odor, turbidity, taste, temperature and
electrical conductivity constitute the physical parameters and are good
indicators of contamination. For instance, color and turbidity are visible
evidences of polluted water while an offensive odor or a bitter and
difference than normal taste also makes water unfit for drinking.
8. ii) Chemical parameters: These include the amount of carbonates,
sulphates, chlorides, fluorides, nitrates, and metal ions. These
chemicals form the total dissolved solids, present in water.
iii) Biological parameters: The biological parameters include matter like
algae, fungi, viruses, protozoa and bacteria. The life forms present in
water are affected to a good extent by the presence of pollutants. The
pollutants in water may cause a reduction in the population of both
lower and higher plant and animal lives. Thus, the biological
parameters give an indirect indication of the amount of pollution in
water.
11. Water pollution in Nigeria according to Gbamanija (1998) arises from
various activities,
among which are:
(i) Sewage leakages
(ii) High population density
(iii) oil spillage
(іv) Industrial waste dumped into our waters
(v) Pollution of ground water through drilling activities
(vi) Radioisotopes
SOURCES OF WATER POLLUTION
12. (vii)Heavy metal
(viii) Combustion
(ix) Toxic waste disposal at sea
(x) Mineral processing plant (e.g. coal production)
(xi) Eroded sediments
(xii) Deforestation
(xiii) Mining
(xiv) Littering
(xv) Pesticides
13. Causes of water Pollution
Marine dumping
Industrial wastage
sewage
Mainly from households
Nuclear waste
Oil pollution
Underground storage leakage
Agricultural
14.
15.
16. Acid Rain is one the causes of Water Pollution:
Acid rain has many ecological effects, but none is greater than its impact on lakes,
streams, wetlands, and other aquatic environments. Acid rain makes waters acidic,
and causes them to absorb the aluminum that makes its way from soil into lakes
and streams.
Pollutants that cause acid rain:
H₂O + SO₂ = H₂SO₄
H₂SO₄ ↔H⁺ + HSO₄⁻ ↔ 2H⁺ + SO₄⁻⁻
Sulfur dioxide reacts with water to form sulfuric acid in the atmosphere which
dissociates into sulfates and hydrogens ions. And hydrogen ion makes a solution
acidic.
17. Another reaction;
NOₓ + H₂O → HNO₃
HNO₃ ↔ H⁺ + NO₃⁻
Nitrogen oxides reacts with water to form Nitric acid, which also
dissociates into hydrogen and nitrate ions.
18. Types of Water Pollution
Fresh water pollution may be classified into two types: surface water
pollution and ground water pollution.
Surface Water Pollution
• When pollutants enter a stream, river or lake these gives rise to
surface water pollution. The surface water pollution has a number of
sources. These can categorized as:
Point and Non-point Sources
Natural and Anthropogenic Sources
19. (i) Point and Non-point Sources
• The well-defined sources that emits pollutants or effluents directly
into different water bodies of fresh water are called point sources.
(ii) Natural and Anthropogenic Sources
• An increase in the concentration of naturally occurring substances is
also termed pollution. The sources of such an increase are called
natural sources. Siltation (which includes soil, sand and mineral
particles) is one such natural source. The human activities that result
into the pollution of water are called anthropogenic.
20. Other Types of Water Pollution
• Sewage
• Disease-causing agents
• Sediment pollution
• Inorganic plant and algal nutrients
• Organic compounds
• Inorganic chemicals
• Thermal pollution
27. Effects of Water Pollution
The effects of water pollution are varied and depend on what
chemicals are dumped and in which locations.
Many water bodies near urban areas (cities and towns) are highly
polluted. This is the result of both garbage dumped by individuals and
dangerous chemicals legally or illegally dumped by manufacturing
industries, health centers, schools and market places.
Effects:
i. Death of aquatic animals
ii. Disruption of the food chain
iii. Diseases
iv. Destruction of ecosystem
28. Death of Aquatic Animals
The main problem caused by water pollution is that it kills life that
depends on these water bodies. Dead fish, crabs, birds and sea gulls,
dolphins, and many other animals often wind up on beaches, killed
by pollutants in their habitat (living environment).
29. Disruption of Food Chain
Pollution disrupts the natural food chain as well. Pollutants such as lead
and cadmium are eaten by tiny animals. Later, these animals are
consumed by fish and shellfish, and the food chain continues to be
disrupted at all higher levels.
30. Diseases
Eventually, humans are affected by this process as well. People can get
diseases such as hepatitis by eating seafood that has been poisoned. In
many poor nations, there is always outbreak of cholera and diseases as
a result of poor drinking water treatment from contaminated waters
31. Destruction of Ecosystem
Ecosystems (the interaction of living things in a place, depending on
each other for life) can be severely changed or destroyed by water
pollution. Many areas are now being affected by careless human
pollution, and this pollution is coming back to hurt humans in many
ways.
32.
33. Pollution management and Control
There are many approaches that could be adopted in water pollution
control and management. It could be through prevention, practice
efforts or join a project/program; Regulation and monitoring or
engaging in control measures by reducing or minimizing waste.
(i) Wash your car far away from any storm water drains.
(ii) Don’t throw trash, chemicals or solvents into sewer drains
(iii) inspects your septic system every 3 – 5 years
34. (iv) avoid using pesticides and fertilizers that can run off into water
systems
(v) sweep your driveway instead of hosing it down
(vi) always pump your waste-holding tanks on your boat
(vii) use non-toxic cleaning materials
(viii) clean up oil and other liquid spills with kitty litter and sweep them
up
(ix) don’t wash paints brushes in the sink.
Regulation and monitoring is an effective way of pollution
management.
35. Pollution control means to control the emissions and effluents into the air,
water and land or soil. Without pollution control, the waster products from
consumptions, heating, agriculture, mining, manufacturing, transportation
and other human activities, whether they accumulate or disperse, will
degrade the environment. Pollution prevention and waste minimization are
more desirable than pollution control. However, pollution could be
minimize by adopting these practices
(i) by recycling (ii) by reusing
(iii) waste minimization (iv) by mitigating
(v) by preventing (vi) by compost.
36. Water Treatment
The treatment of this waste water is carried out in the following three
stages:
(i) Primary treatment
(ii) Secondary treatment, and
(iii) Tertiary treatment
Primary Treatment: When the waste water is to be dumped off into a
river or flowing steam, the treatment is carried out by sedimentation,
coagulation and filtration. This is known as primary treatment. If the
water is required for drinking purposes, it has to undergo further
treatment called secondary and tertiary treatments. The following steps
are performed to do primary treatment of water:
37. Sedimentation: This step is carried out in large tanks specially built for
this purpose in sewage treatment plant. The polluted water is allowed
to settle so that silt, clay and other matter settle to be bottom and
water is slowly allowed to move out. Fine particles do not settle and
are thus required to be removed in the next step.
38. Coagulation: Fine particles and colloidal suspension are combined into
large particles by a process called coagulation. This step is carried out
by the addition of special chemicals called coagulants (flocculants) such
as potash alum. The large particles either settle to the bottom or are
moved in the next step.
39. Filtration: Suspended particles, flocculants, bacteria and other
organisms are filtered by passing the water through a bed of sand or
finely divided coal or through some fibrous materials. The total
impurities collected in these steps are called sludge. It is used as a
valuable fertilizer. On composting (i.e. the action of anaerobic bacteria),
it releases sludge gas. It consists mainly of methane gas which is used
for cooking purposes.
40.
41. Secondary or Biological Treatment: The water after primary treatment
is not fit for drinking purposes and has to undergo further treatment.
This is done through secondary or biological treatment. A commonly
used method is to allow polluted water to spread over a large bed of
stones and gravel so that the growth of different microorganisms
needing nutrients and oxygen is encouraged. Over a period of time a
fast moving food chain is set up. For example, bacteria consume
organic matter from the polluted water; protozoa live on bacteria.
Every form of life including algae and fungi help in the cleaning up
process. This is called secondary treatment of water. It involves the
following processes
42. Softening : By this treatment undesirable cations of calcium and
magnesium are removed from hard waters. Either water is treated with
lime and soda ash to precipitate Ca2+ ions as carbonates or it is passed
through cation exchangers. This makes water soft.
43. Aeration: In this process, soft water is exposed to air by forcing air
through it to add oxygen to water. This encourages bacterial
decomposition of organic matter into harmless products such as
carbon dioxide and water. The addition of oxygen reduces carbon
dioxide, sulphide etc.. The water is as yet not fit for drinking purposes.
The pathogenic and other microorganisms need to be killed. This is
done in the next treatment.
44. Tertiary Treatment : The tertiary treatment is actually disinfecting
water. Chlorine is the most commonly used disinfectant used for killing
bacteria. However, chlorine also reacts with traces of organic matter
present in water and forms undesirable chlorinated hydrocarbons (toxic
and potentially carcinogenic). It is therefore desirable to reduce the
organic matter in water before passing chlorine gas. Other methods of
disinfection such as ultraviolet radiation, ozone gas treatment or
reverse osmosis are preferred over chlorine treatment. But these
methods are more expensive.
45. Sewage is one of the major causes of water borne diseases and therefore
the treatment of sewage is one of the important tasks. For a long time
treatment of municipal waste in the form of sewage involved mainly of
the removal of suspended solids, oxygen demanding materials and
harmful bacteria. Now the disposal of the solid residue from sewage has
been improved by applying municipal treatment processes.
Septic tanks
Primary (physical) sewage treatment
Secondary (biological) sewage treatment
Urban sewage treatment (Clean Water Act)
50. The problems associated with water pollution have the capabilities to
disrupt life on our planet to a great extent. Congress has passed laws to try
to combat water pollution thus acknowledging the fact that water
pollution is, indeed, a serious issue. But the government alone cannot
solve the entire problem. It is ultimately up to us, to be informed,
responsible and involved when it comes to the problems we face with our
water. We must become familiar with our local water resources and learn
about ways for disposing harmful household wastes so they don't end up
in sewage treatment plants that can't handle them or landfills not
designed to receive hazardous materials. In our yards, we must determine
whether additional nutrients are needed before fertilizers are applied, and
look for alternatives where fertilizers might run off into surface waters. We
have to preserve existing trees and plant new trees and shrubs to help
prevent soil erosion and promote infiltration of water into the soil
Conclusion
