CHEMISTRY PROJECT
REPORT
STUDY OF METHODS OF
PURIFICATION OF WATER
Shreya Sanjay
12TH GRADE
SRI CHAITANYA TECHNO COLLEGE
INDEX
Sr No Particulars Pg No
1 INTRODUCTION 2
2 WHAT IS WATER PURIFICATION? 3
3 WHY IS WATER PURIFICATION IMPORTANT? 4
4 TYPES OF IMPURITIES IN WATER 4
5 METHODS OF WATER PURIFICATION 5-10
6 CONCLUSION 11
7 BIBLIOGRAPHY 12
1
INTRODUCTION
Water often called the elixir of life, is fundamental to all living
organisms and critical for human survival. Despite covering
approximately 71% of the Earth’s surface, only a small fraction of
water is accessible and fit for consumption.
This scarcity of clean and safe water poses a significant global
challenge, particularly in underdeveloped and developing regions
where contamination is prevalent. Water pollution stems from
various sources, including industrial discharge, agricultural runoff,
and inadequate sanitation systems. These contribute to a host of
physical, chemical, and biological impurities that render water unfit
for drinking, cooking, and other essential uses.
Contaminated water not only jeopardizes public health by spreading
diseases but also disrupts ecosystems, leading to long-term
environmental damage. Addressing these challenges necessitates an
in-depth understanding of water purification techniques to ensure
the availability of safe water for domestic, industrial, and agricultural
applications.
This project explores various purification methods, shedding light on
their mechanisms, advantages, and limitations. It underscores their
vital role in mitigating water contamination issues and ensuring
access to clean water across diverse scenarios.
2
THEORY
WHAT IS WATER PURIFICATION?
Water purification is the process of removing contaminants from water to
make it suitable for specific purposes, such as drinking, industrial
processes, or irrigation. This involves the elimination of undesired
chemical compounds, physical impurities, and biological pathogens to meet
health and safety standards. Techniques range from basic filtration to
advanced chemical and physical treatments, each targeting specific
impurities and providing tailored solutions for various scenarios.
3
WHY IS WATER PURIFICATION IMPORTANT?
The significance of water purification lies in its ability to protect human
health, support sustainable development, and preserve the environment.
Contaminated water can cause severe health issues, including waterborne
diseases like cholera, typhoid, and dysentery. Prolonged exposure to
pollutants, such as heavy metals and industrial chemicals, may result in
chronic illnesses and developmental issues.
Beyond individual health, purified water is critical for agricultural
productivity, industrial operations, and energy generation, emphasizing its
pivotal role in economic and social progress. Ensuring access to clean
water is thus fundamental to building resilient communities and
safeguarding the environment.
TYPES OF IMPURITIES IN WATER
Water contains a range of impurities broadly classified as follows:
● Physical Impurities: Suspended particles like sand, silt, and other
visible debris that make water appear turbid. These impurities affect
taste and can clog filtration systems.
● Chemical Impurities: Dissolved substances such as salts, toxic
metals (e.g., lead and arsenic), and industrial pollutants. These can
cause health risks, including organ damage and carcinogenic effects.
● Biological Impurities: Microorganisms like bacteria, viruses, fungi,
algae, and protozoa that thrive in untreated water. These pathogens
are responsible for infectious diseases, particularly in warm and
stagnant conditions.
4
METHODS OF WATER PURIFICATION
BOILING
Boiling is a simple and effective method of making water potable by killing
harmful microbes and viruses. Although the sensitivity of microorganisms
to heat varies, most can be inactivated by holding water at its boiling point
of 100°C (212°F) for just one minute. Boiling is often recommended as an
emergency water purification method, particularly in areas without access
to proper purification systems, such as in rural settings or during
wilderness expeditions. However, while boiling effectively eliminates
biological contaminants, it does not remove chemical toxins or other
impurities, making it a temporary solution rather than a comprehensive
purification method.
5
REVERSE OSMOSIS
Reverse osmosis is a highly effective water purification process that utilizes
a semi-permeable membrane to remove unwanted molecules, large
particles, and contaminants such as chlorine, salt, and dirt from drinking
water. The process works by applying pressure to the water, forcing it to
flow in the reverse direction of its natural osmotic movement—from a high
concentration of contaminants to a lower concentration. As the water
passes through the membrane, impurities are trapped, allowing only
purified water to pass through. This results in exceptionally clean and safe
drinking water, making reverse osmosis a preferred method for removing
even the smallest impurities.
6
DISTILLATION
Distillation is one of the oldest and most effective methods of water
purification, relying on the process of evaporation and condensation to
remove contaminants. In this process, contaminated water is heated to
form steam. As the water evaporates, it leaves behind inorganic
compounds, large non-volatile organic molecules, and other impurities that
do not vaporize. The steam is then cooled and condensed back into liquid
form, resulting in purified water that is free of most contaminants.
This method is particularly effective in removing bacteria, inorganic
substances, and many organic compounds. Home distillation units provide
a viable option for people facing water quality issues, offering a reliable
solution for obtaining safe drinking water. While distillation effectively
eliminates a wide range of impurities, it is often used alongside other
methods for comprehensive purification.
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UV WATER PURIFICATION
UV water purification is an advanced method of disinfecting water by
utilizing ultraviolet (UV) rays to eliminate harmful microorganisms. UV
rays effectively kill waterborne pathogens by disrupting their DNA,
preventing them from reproducing, and ensuring they are completely
neutralized. Unlike other purification methods, UV treatment does not
involve chemical additives, which means it preserves the natural taste of
water while ensuring it is free of harmful microbes.
Modern UV water purifiers use low-pressure mercury vapor lamps that
emit UV radiation at a specific wavelength to maximize disinfection
efficiency. These lamps are strategically installed to avoid direct contact
with water, ensuring safety and effectiveness.
One of the primary benefits of UV water purification is its speed—water is
purified almost instantly. Additionally, UV systems are cost-effective, as the
mercury vapor lamps consume power comparable to a standard light bulb
and are relatively affordable to replace. With proper maintenance, UV
water purifiers can offer long-lasting performance, making them a reliable
and environmentally friendly solution for safe drinking water.
8
CLAY POT FILTRATION
Clay pot filtration is one of the oldest methods of water purification,
utilizing simple and natural materials to filter contaminants. The filter
itself is shaped like a flowerpot and can hold approximately 8-10 liters of
water. It is placed inside a plastic or clay receptacle to collect the filtered
water. To use, water is poured into the top receptacle, where it gradually
flows through the porous clay filter into a storage container. The treated
water is accessed via a spigot attached to the storage receptacle.
The effectiveness of clay pot filters largely depends on the quality of their
production. High-quality filters can effectively remove bacteria and larger
protozoans but are generally less effective at removing smaller viruses.
Additionally, poor-quality filters or improper maintenance can lead to
significant bacterial contamination, particularly at the household level.
9
WATER CHLORINATION
Water chlorination is a widely used process for disinfecting water by
adding chlorine or chlorine compounds, such as sodium hypochlorite. This
method effectively kills bacteria, viruses, and other microbes, making it a
critical tool in preventing waterborne diseases like cholera, dysentery, and
typhoid. Chlorine, as a halogen, is a highly efficient disinfectant added to
public water supplies to eliminate disease-causing pathogens that can
thrive in reservoirs, water mains, and storage tanks.
As a strong oxidizing agent, chlorine works by oxidizing organic molecules
in pathogens. It penetrates the negatively charged surfaces of
microorganisms, disrupts their lipid membranes, and interacts with
intracellular enzymes and proteins, rendering them non-functional. This
process ensures that microorganisms are either killed or rendered
incapable of reproduction, making water safe for consumption.
10
CONCLUSION
Water purification is essential for providing safe drinking water and
protecting public health. Contaminated water poses significant health risks,
and purification methods address these challenges effectively. Advanced
techniques like reverse osmosis and UV purification offer superior
efficiency in removing contaminants and pathogens, making them ideal for
urban and industrial settings.
Traditional methods such as boiling and clay pot filtration remain valuable
in resource-limited areas, offering practical and cost-effective solutions.
However, these methods may need to be complemented by others to
ensure complete safety, especially against chemical pollutants.
In conclusion, the choice of water purification method depends on specific
needs and circumstances. Combining techniques where necessary can
provide a comprehensive approach to ensuring water safety, promoting
health, and supporting sustainable access to clean water.
11
BIBLIOGRAPHY
1. "Water Purification," Wikipedia, The Free Encyclopedia,
https://en.wikipedia.org/wiki/Water_purification.
2. ScienceDirect, Water Purification Methods and Applications,
https://www.sciencedirect.com/topics/agricultural-and-biological
-sciences/water-purification
3. Encyclopaedia Britannica. "Water Purification: Other
Purification Steps.".
https://www.britannica.com/topic/water-purification/Other-purif
ication-steps.
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