An Internship Report on Chittagong Water Supply and Sewerage Authority (CWASA) Submitted by- Quock San MS Environmental Science ID: 08208067 Session: 2011-12 Institute of Forestry and Environmental Sciences, University of Chittagong (IFESCU) Date: 10 th March 2014
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An Internship Report on
Chittagong Water Supply and Sewerage
Authority (CWASA)
Submitted by-
Quock San
MS Environmental Science
ID: 08208067
Session: 2011-12
Institute of Forestry and Environmental Sciences,
University of Chittagong (IFESCU)
Date: 10th March 2014
I
ACKNOWLEDGEMENT
At first, I express my profound gratitude to the God, the gracious and most munificent, who gives me
the energy and sound health to endure the rigor of this job.
We would like to express our profound sense of gratitude to Dr. Tapan Kumar Nath, Professor and
Acting Director, Institute of Forestry and Environmental Sciences, University of Chittagong
(IFESCU), provided us an opportunity to do our internship at Chittagong Water Supply and
Sewerage Authority (CWASA).
Utmost gratitude to The Chief Engineer Md. Abdul Karim Chowdhury of CWASA who accepted us as
an internee at their company and provided us an opportunity to enrich our technical competence as
well as increasing our managerial skillfulness regarding environmental aspects.
Then we would like express our sincerest gratitude to Secretary Md. Samsudduha, and Deputy-
Secretary Jahangir Alam Chowdhury, CWASA for their pleasant and benevolent cooperation.
We owe an immense debt of gratitude to Mr. Milan Kumar Chakraborty, Senior Chemist, Mohara
Water Treatment Plant (WTP), CWASA who helped us all the time by providing necessary
information whenever we need.
We want to express our sincere thanks to Executive Engineers of CWASA Md. Sarfaraj Akhter
(Mohara WTP), Md. Ariful Islam (MOD-2), Md. Mahbubul Alam (MOD-1), and Noor Mohammad
Abul Basher (Design Section) provided us a lot of information, suggestions and accompany us during
work under his supervision in their divisions.
We are thankful to Assistant Engineers of CWASA Mr. Sajib Barua (Mohara WTP), Mr. Soumit
Paul (Booster), Mr. S. M. Rabiul Hossain (MOD-2), Md. Abdur Rouf (MOD-1) for their kind
cooperation, assistance and providing important information in their divisions.
Then we would like to thank Sub-Assistant Engineer of CWASA Mr. Rafiqul Islam for his kind
support, assistance and accompany during our work in his divisions.
We are also indebted to all officials and staffs of CWASA for their cordial help and collaboration
during our work making life easier for us, which will be useful in our future career. We apologize if we
forgot to mention names of other personnel, but however, we are extremely grateful to every one
whatever he/she has offered us during our internship.
Author
10th March 2014
II
TABLE OF CONTENTS
ACKNOWLEDGEMENT I
TABLE OF CONTENTS II
LIST OF TABLES IV
LIST OF FIGURES IV
LIST OF ABBREVIATIONS V
CHAPTER ONE: INTRODUCTION
1.1 General overview 1
1.2 Summary of Existing Facilities of CWASA 2
CHAPTER TWO: MOHARA WATER TREATMENT PLANT
2.1 General information 3
2.2 Halda River 3
2.3 Main Components of Mohara Water Treatment Plant 4
2.4 Treatment process description 4
2.5 Treatment plant design data 7
2.6 Description of Process Unit 8
2.6.1 Intake and Raw Water Pump Station 9
2.6.2 Desilting Basin 9
2.6.3 Rapid Mixture 10
2.6.4 Clarifiers 10
2.6.5 Filters 10
2.6.6 Clear Well and High Lift Pump Station 10
2.6.7 Chemical Facilities 10
2.6.8 Sludge and Backwash Facilities 11
2.6.9 Power Supply and Generator 11
III
2.6.10 Laboratory 11
2.6.11 Plant Monitoring Arrangement 13
CHAPTER THREE: KALURGHAT IRP AND BOOSTER STATION
3.1 General information 15
3.2 Source and Treatment of Water in Kalurghat IRP 15
3.3 Treatment Procedure 16
3.4 Quality of Water 17
CHAPTER FOUR: MAINTENANCE, OPERATIONS AND DISTRIBUTION
(MOD)
4.1 General information 18
4.2 Coverage area: 18
4.3 Main activities: 18
CHAPTER FIVE: DESIGN DIVISION
5.1 Activities 19
CHAPTER SIX: CONCLUSION
6.1 Conclusion 21
IV
LIST OF TABLES
Table 2.1: Daily Water Analysis of Mohara WTP 12
Table 2.2: Weekly Water Analysis of Mohara WTP 12
Table 2.3: Monthly Water Analysis of Mohara WTP 12
Table 2.4: Water Quality of Mohara Water Treatment Plant 13
Table 3.1: Quality of water before and after treatment in Kalurghat Iron Removal
Plant (IRP).
17
LIST OF FIGURES
Figure 2.1: Process Flow Schematic of Mohara WTP 6
Figure 3.1: A Flow Chart of Kalurghat Iron Removal Plant and Booster Station 16
Figure 5.1: The activities of design division of CWASA 20
V
LIST OF ABBREVIATIONS
WASA Water Supply and Sewerage Authority
CWASA Chittagong Water Supply and Sewerage Authority
WTP Water Treatment Plant
Ctg Chittagong
KV Kilovolt
KVA Kilovolt Ampere
Km Kilometer
MGD Million gallons per day
NTU Nephelometric Turbidity Unit
MLD Million Liters Per day
imp gal Imperial gallon
sft Square feet
ft Foot
m Meter
mm Millimeter
gm Gram
I or L Liter
Mg/l Milligram/liter
kw Kilowatt
lbs Pounds
ml Million liters
d Day
gpd Gallons per day
gpm Gallons per minute
fph Feet per hour
mg Million gallons
mil Million
gal Gallon
kg Kilogram
hr Hour
hp Horse Power
IRP Iron Removal Plant
PC Personal Computer
LCD Lower Circuit Panel
MOD Maintenance, Operation and Distribution
WHO World Health Organization
DO Dissolve Oxygen
BOD Biological Oxygen Demand
COD Chemical Oxygen Demand
TDS Total Dissolve Solids
Coli. Coli form
BWDS Bangladesh Water Standards
VI
PDB Power Development Board
MIS Management Information System
Internship Report
Institute of Forestry and Environmental Sciences, University of Chittagong 1
CHAPTER ONE
INTRODUCTION
1.1 General overview
Chittagong is the second largest city of Bangladesh. A part from being the main centre of trade,
commerce and industrial activities is the life line of the economy for its sea port. Country's first
Export Processing Zone was established in this city. Over the last 3 decades, Chittagong has
grown at a great pace. This decade's remarkable phenomenon in the economy of the country is
unprecedented growth of garment industry in Chittagong. Development of industries has brought
rapid increase of population. Chittagong has witnessed major growth in population over the last
3 decades; mainly due to migration from the country-side. Since 1971, the population of the city
has grown from about 0.5 million to more than 3.0 million in 2007. The city area has also
expanded. The total area of Chittagong and sub-urban areas (including proposed Hathazari and
Sitakunda) is around 270 sq. km. This kind of growth presents tremendous challenges to the
utility authorities in providing utility services. Chittagong WASA, responsible for the water
supply of port city has taken up its all necessary steps to digitalize its overall operations. For easy
access of the respected consumers to the information and data regarding CWASA, an website
has been launched. Through this website a new dimension has been added in its communication
with the respected consumers. For better customer service, CWASA facilitated the consumers
with online billing system. For improved operations of CWASA, heartiest co-operation from the
respected consumers is highly expected. CWASA is striving hard to keep pace with the city
development.
Internship Report
Institute of Forestry and Environmental Sciences, University of Chittagong 2
1.2 Summary of Existing Facilities of CWASA
Facility Quantity Capacity
Surface WTP 1 no. 90 MLD
Ground WTP 1 no. 68 MLD
Deep Wells 91 nos. 115 MLD
Pipeline 610km -
Reservoirs 14 46,142 ML
HL & Booster 4 & 3 -
Service Conn. 57,043 nos. -
Internship Report
Institute of Forestry and Environmental Sciences, University of Chittagong 3
CHAPTER TWO
MOHARA WATER TREATMENT PLANT (WTP)
2.1 General information
The Mohara Water Treatment Plant is the part of the city of Chittagong Water Supply
and Sewerage Authority’s (CWASA).
Commissioning: Commissioned in December 1987.
Capacity: Its Capacity is 20 million gallon per day (MGD).
Source: River Halda at a point nearly half a mile upstream from its confluence with
the river Karnaphuli.
2.2 Halda River
Originates at the Badnatali Hill ranges in Ramgarh Upazila in the Ctg. Hill Tracts.
Flows through Fatickchari Upazila, Hathazari Upazila, Raozan Upazila and Kotwali
Thana, and falls into the Karnaphuli River.
81km long river has a very turbulent tributary.
The Dhurung River, which joins Purba Dahlai about 48.25 km downstream.
Navigable by big boats 25km into it (up to Nazirhat) and by small boats 16-24km
further (up to Narayanhat).
Halda is famous for breeding Pure Indian carp.
This is the only pure Indian carp breeding field of Bangladesh, perhaps in South Asia.
2.3 Main Components of Mohara Water Treatment Plant
Intake and Raw Water Pump Station
Desilting Basin
Rapid Mixer
Clarifier
Filter
Chlorine Contact Chamber and Clear Well
High Lift Pump Station
Chemical Facility
Internship Report
Institute of Forestry and Environmental Sciences, University of Chittagong 4
Sludge and Backwash Facility
Power and Standby Generator
Laboratory
Plant Monitoring Arrangement
2.4 Treatment process description
The objectives of the Mohara water treatment plant are not only to provide safe water for
human consumption and appealing to consumers, but to bring the water quality within the
limit of the maximum allowable standards set by the World Health Organization (WHO).
The raw water for the Mohara Water Treatment Plant is taken from the Halda River. The
Halda River Water contains varying level of alkalinity (10-75 mg/l) and turbidity (15-350
NTU). These variations are a result of seasonal changes with the monsoon season causing the
higher turbidities, low alkalinities and high level of suspended solids. The overall treatment
process units include an intake structure with bar racks, pump station, raw water rising main,