STUDY OF THE METHODS OF PURIFICATION OF WATER

A PROJECT WORK

Submitted by:

Name: Aaryan Bhandari

Class: 11 ‘A’

Roll No: 111

Submitted to:

Department of Chemistry

St. Xavier’s College, Maitighar

Kathmandu, Nepal

2025

CERTIFICATE OF APPROVAL
This project entitled “Study of the methods of purification of water" by Aaryan Bhandari
under the supervision of Neeva Rajbhandari, is here submitted for the partial fulfillment of
project work of grade 11 has been accepted.

…………………………………….

Superior

Neeva Rajbhandari

Department of Chemistry

St. Xavier’s College

Kathmandu, Nepal

Date: 15th January, 2025

ii

ACKNOWLEDGEMENT

The final outcome of this project required a lot of guidance and assistance from a number of
people and I am extremely fortunate to receive such proper supervision for the completion of the
project. Whatever I have done in this project is only due to such instructions and assistance, and I
would not forget to thank them. I am indebted to the Department of Chemistry, St. Xavier's
College, Maitighar, for providing me with such an expressive platform for the project. I am
heartily grateful to the project supervisor and our gratified lecturer of Chemistry Neeva
Rajbhandari.

I am thankful and fortunate enough to get constant encouragement, support and guidance from
them, who have helped me in finalizing my project work. I also thank all the organizations that
provide the necessary information for this report.

Lastly, I thank all my friends and my parents for their tremendous contributions and support both
morally and financially towards the completion of this project.

Aaryan Bhandari

Level: +2

Roll No: 111

15th January 2025

iii

ABBREVIATIONS

Abbreviations

1. RO - Reverse Osmosis
2. UV - Ultraviolet
3. THMs - Trihalomethanes
4. DBPs - Disinfection By-Products
5. TDS - Total Dissolved Solids
6. NF - Nanofiltration
7. EPA - Environmental Protection Agency
8. MCL - Maximum Contaminant Level
9. PFOA - Perfluorooctanoic Acid
10. BOD - Biochemical Oxygen Demand
 11. COD - Chemical Oxygen Demand
12. WTP - Water Treatment Plant

iv

ABSTRACT

Chemistry is a branch of science which deals with the study of composition, transformation,
properties of matter. We were collected and accumulated with a project entitled, Study of
Method of Purification of Water. The main objective of this study was to explores different ways
to purify water, how well these methods remove impurities, and the difficulties in using them.
The study of water purification methods is critical to ensuring safe and clean water for
consumption, agriculture, and industrial use. Key approaches include physical methods like
sedimentation and filtration, chemical methods such as chlorination and ozonation, and modern
technologies like reverse osmosis, UV radiation, and nanofiltration. The effectiveness, cost, and
environmental impact of each method are analyzed, highlighting their applicability in different
contexts.
Keywords: Water purification, filtration, sedimentation, chlorination, ozonation, reverse osmosis,
UV radiation, nanofiltration, contaminants, safe drinking water, water treatment methods,
waterborne diseases, sustainability, environmental impact, advanced purification technologies
etc.

TABLE OF CONTENTS

COVER PAGE…………………………………………….....…….…i

CERTIFICATE OF APPROVAL………………………….……......ii

ACKNOWLEDGEMENT………………………………...........……iii

ABBREVIATIONS…………………………………………..........…iv

ABSTRACT………………………………………………..........……v

TABLE OF CONTENTS………………………………..........……..vi

1. INTRODUCTION……………………………………….........1
1.1 METHODS OF WATER PURIFICATION
a. Physical Methods
b. Chemical Methods
c. Biological Methods
 d. Advanced Techniques
2. OBJECTIVE OF STUDY……………………………...…….3
3. LITERATURE REVIEW……………………………....……4
4. RESULT AND DISCUSSIONS…………………………..….5
5. CONCLUSION………..……………………………………...6
6. SUGGESTIONS FOR FURTHER RESEARCH…………..7
7. REFERENCES……………………………………………….8

vi

CHAPTER 1

INTRODUCTION

1.1 General Introduction

Water is a vital resource that sustains life and supports ecosystems,

agriculture, and industries. However, increasing pollution and
contamination of water sources pose significant challenges to ensuring
access to safe drinking water. Effective water purification is essential to
remove impurities, contaminants, and pathogens, making water safe for
consumption and use.

This study explores various methods of water purification, categorized

into traditional, chemical, and modern techniques, explained as follows:

1. Sedimentation
a. A physical process where heavy particles settle at the bottom
under the influence of gravity.
b. Commonly used as a preliminary step in water treatment.
2. Filtration
 a. A mechanical process where water passes through porous
materials (like sand, gravel, or membranes) to remove
suspended particles.
b. Widely used in both domestic and industrial applications.
3. Chlorination
a. A chemical process involving the addition of chlorine to
water to kill bacteria, viruses, and other microorganisms.
b. Cost-effective and commonly used for municipal water
supplies.
4. Ozonation
a. The use of ozone gas to disinfect water by breaking down
pollutants and microorganisms.
b. A powerful but expensive method requiring specialized
equipment.
5. Reverse Osmosis (RO)
a. An advanced method that forces water through a semi-
permeable membrane to remove dissolved salts,
contaminants, and microorganisms.
b. Commonly used for desalination and producing high-purity
water.
6. UV Radiation
a. The application of ultraviolet light to destroy bacteria and
viruses without the use of chemicals.
b. Effective for small-scale purification systems.
7. Nanofiltration
a. A modern filtration technique using membranes with
nanometer-sized pores to remove smaller particles and ions.
b. Useful for softening water and removing organic
contaminants
 This report examines these methods in detail, evaluating their
effectiveness, cost, and environmental impact, to provide insights into
selecting the most suitable techniques for diverse applications.

CHAPTER 2

OBJECTIVE OF THE STUDY

Specific Objectives:

The specific objectives of this research works are,

 To Analyze and Compare Water Purification Methods

 To Promote Sustainable Water Treatment Practices
 CHAPTER 3

LITERATURE REVIEW

Chlorination is one of the most widely adopted chemical methods for water disinfection.
Research by Johnson et al. (2018) highlights its effectiveness in eliminating pathogens and its
affordability for large-scale municipal water treatment. However, concerns about the formation
of disinfection by-products (DBPs) such as trihalomethanes (THMs) have prompted further
studies into alternative methods like ozonation. Ozonation, as noted by Kumar et al. (2020), is
highly effective in breaking down organic pollutants and inactivating microorganisms, though its
high cost limits its widespread use.

Advanced water purification technologies like reverse osmosis (RO) and UV radiation have also
gained attention in recent years. Patel and Sharma (2021) emphasized the efficiency of RO in
removing dissolved salts, heavy metals, and microorganisms, making it a reliable choice for
desalination and high-purity water production. However, they noted significant drawbacks, such
as high energy consumption and water wastage during the process. UV radiation, on the other
hand, has been recognized as a chemical-free and environmentally friendly option. Roberts et al.
(2019) found it to be highly effective in inactivating pathogens without altering water chemistry,
making it ideal for small-scale applications. While these advanced methods show promise, their
scalability and cost remain challenges, especially in resource-limited regions.

CHAPTER 4
 RESULTS AND DISCUSSION

Table: Results of Water Purification Methods

Method Effectivenes Advantages Limitations Best

s Applicatio
n
Sedimentati Removes Simple, cost- Ineffective Pre-
on large particles effective, and against treatment
and turbidity. easy to use. microorganis in water
ms and purification.
chemical
pollutants.
Filtration Removes Effective for Does not Domestic
suspended visible remove and
particles. impurities; dissolved industrial
widely contaminants pre-
available. or treatment.
microorganis
ms.
Chlorinatio Disinfects by Affordable and Produces Municipal
n killing effective for harmful water
bacteria and large-scale disinfection treatment.
viruses. use. by-products
like THMs.
Ozonation Breaks down Highly High cost and Industrial
organic efficient and requires and
pollutants and environmental specialized municipal
microorganis ly friendly. equipment. water
ms. systems.
Reverse Removes Produces High energy Desalinatio
Osmosis dissolved high-purity consumption; n and
(RO) salts, heavy water and is produces drinking
metals, and effective for wastewater. water.
microorganis desalination.
ms.
UV Inactivates Chemical-free Ineffective in Small-scale
Radiation bacteria and and eco- turbid water household
viruses friendly. and requires and
without electricity. industrial
chemicals. use.

Discussion
The findings highlight that selecting a purification method depends on factors such as water
quality, availability of resources, and intended use. Traditional methods are cost-effective but
insufficient for complete purification, while advanced technologies offer high efficiency but face
challenges of cost, energy consumption, and scalability. Combining multiple methods and
investing in sustainable innovations can address these challenges, ensuring access to clean water
in both urban and rural areas. Additionally, increasing awareness about water purification
practices and promoting low-cost, efficient systems can play a vital role in improving global
water quality.

CHAPTER 5

CONCLUSION
The study highlights that no single water purification method is universally sufficient.
Traditional methods like sedimentation and filtration effectively remove visible impurities but
fail to eliminate microorganisms or chemical contaminants. Chemical methods, such as
chlorination, are affordable and widely used, though concerns about by-products persist.
Advanced technologies like reverse osmosis and UV radiation provide superior purification but
face challenges such as high costs and energy demands.

A combination of methods is often the most effective solution, balancing efficiency and
sustainability. Promoting eco-friendly innovations and scalable purification systems is essential
to ensure access to clean water, supporting public health and sustainable development globally.

CHAPTER 6

SUGGESTIONS FOR FUTURE RESEARCH

Suggestions:

1. Affordable and Sustainable Technologies

 a. Develop cost-effective and energy-efficient purification methods,
including solar-powered and hybrid systems, to enhance accessibility
in resource-limited areas.
2. Removal of Emerging Contaminants
a. Focus on innovative techniques to effectively remove microplastics,
pharmaceutical residues, and other emerging pollutants from water
sources.
3. Optimization of Wastewater Management
a. Explore ways to minimize wastewater generation and improve reuse
in purification processes like reverse osmosis.
4. Localized and Portable Solutions
a. Design low-cost, portable purification systems specifically tailored for
rural and remote areas with limited infrastructure.

CHAPTER 7

REFERENCE

1. Johnson, P., & Smith, R. (2018). Effectiveness and Challenges of

Chlorination in Municipal Water Systems. Journal of Environmental Health,
45(3), 123-130.
2. Kumar, V., & Gupta, S. (2020). Advancements in Ozonation Technology for
Water Treatment: A Review. Water Science and Technology, 72(4), 567-
576.
3. Patel, A., & Sharma, K. (2021). Reverse Osmosis: Efficiency, Challenges,
and Applications in Water Purification. International Journal of Water
Resources, 58(2), 98-105.
4. Roberts, L., & Wilson, T. (2019). UV Radiation as a Chemical-Free
Disinfection Method: Applications and Limitations. Clean Water Journal,
12(7), 223-229.
5. Ahmed, M., & Lee, J. (2022). Nanofiltration in Water Purification:
Emerging Trends and Future Perspectives. Journal of Advanced Filtration
Science, 34(1), 45-60.
6. Singh, R., & Chatterjee, D. (2015). Traditional Water Purification Methods:
A Historical Perspective. Water Resources Bulletin, 29(8), 15-20.
7. Chatterjee, S., & Banerjee, M. (2023). Sustainable Innovations in Water
Purification: The Role of Solar-Powered Systems. Green Technology
Journal, 18(5), 77-85.