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U N I V E R S I T Y O F N A I R O B I

S C H O O L O F E N G I N E E R I N G

DEPARTMENT OF ENVIRONMENTAL AND BIOSYTEMS ENGINEERING

FEB 540: ENGINEERING DESIGN PROJECTFEB 540: ENGINEERING DESIGN

PROJECT

FEB 540: ENGINEERING DESIGN PROJE

PROJECT TITLE

DESIGN OF A RAW WATER TREATMENT PLANT

CASE STUDY:MOSIABANO DAM NYANSIONGO WARD, BORABU CONSTITUENCY

NAME: NYAKUNDI BRENDA KWAMBOKA

REGISTRATION NUMBER: F21/1978/2013

SUPERVISOR: MR. J.O AGULLO

A design projectsubmitted in partial fulfilment of the requirement for the Award of the

Bachelor of Science Degree in Bio-systems Engineering at the University of Nairobi.

JUNE 2018

i

FEB 540: ENGINEERING DESIGN PROJECT

2017/2018 ACADEMIC YEAR

DECLARATION

I, Nyakundi Brenda Kwamboka, hereby declare that this projectis my original and with

sincerity and to the best of my knowledge, it has not been presented for any degree award at

any other higher institution of learning.

Signature …………………………………………

Date …………………………………………

Nyakundi Brenda Kwamboka

F21/1978/2013

This project report has been submitted for examination with my approval as the supervisor.

Signature………………………………………...

Date ………………………………………..

Mr. J. O Agullo

i

DEDICATION

This research proposal is dedicated to my family especially my father Thomas Nyakundi who

has been a great motivation in my academic journey.

ii

ACKNOWLEDGEMENT

This research study is a result of support from several sources; first I would like to give praise

and honor to the Almighty God for giving me sufficient grace and power to write this project.

I would also like to thank my supervisor Mr. Januarius Agullo whose comments and advice

were very useful to me, my family for the encouragement and moral support as well as to my

friends for their encouragement and support too. May God bless them in every way I say

thank you, they all gave me the motivation that was key to my achievements in writing

thisproposal. Lastly I would like to acknowledge the University of Nairobi for the good and

conducive learning environment during my study period, as well as the resources from the

library. Thanks a lot and God bless you.

iii

ABSTRACT

Water is a very intergral part in our daily life. It’s, dubiously a basic human need. Providing

safe and adequate quantities of the same for all remains an important undertaking throughout

the world as outlined in the Sustainable Development Goal No 6. This is equally echoed in

the Kenya Vision 2030 plan that drives the country towards political, economic and social

positive steering of the economy. This project involves the design of a gravity water supply

system.

The overall objective of this project was to design a raw water treatment system for

Mosiabano dam, at Nyansiongo Ward in Nyamira County. The specific objectives of the

study were to: Determine the water utilization/demand in the area, to evaluate the raw water

quality tests from Mosiabano Dam and to design the specifications for Mosiabano dam raw

water treatment works and related components.

The water quality tests were performed at the University of Nairobi’s civil Engineering

laboratory so as to achieve the World Health Organisation requirements. The design of the

major components of the treatment plant, mainly flocculation, sedimentation, filtration and

water storage tanks were based on design criteria (and parameters) that are recommended for

design of water treatment plants to ensure that the plants would function effectively. The

design considerations wereon dimensioning of the tanks ratios as per certain ranges to allow

for effective water treatment. Other considerations that were considered are: retention time

within the tanks and surface loading rates.

It was important to design a plant capacity that will satisfy the water demand of the

population therefore population studies were important in the design. This includes the

households, their animals as well as infrastructural facilities such as schools and hospitals.

The presence of a safe and reliable source of water is thus an essential prerequisite for the

establishment of a stable community. The presence of safe and reliable source of water is

necessary for the people of Nyansiongo and everyone.

The outcome of the projectwas determined as successful at the end of the project. They

include the design a raw water treatment system that will supply safe and clean water that

meets the demand of people in Nyansiongo Town in Nyansiongo Ward, Borabu Constituency

as well as determine the amount of water demand in the region, perform water quality tests

on the water and also determine the specifications for the raw water treatment works and

related components. There was need for an AutoCAD design for the water treatment works.

iv

TABLES OF CONTENTS

DECLARATION..............................................................................................................................i

DEDICATION.................................................................................................................................ii

ACKNOWLEDGEMENT..............................................................................................................iii

ABSTRACT...................................................................................................................................iv

TABLES OF CONTENTS..............................................................................................................v

LIST OF TABLES AND FIGURES............................................................................................viii

LIST OF ABBREVIATIONS.........................................................................................................ix

CHAPTER 1....................................................................................................................................1

INTRODUCTION...........................................................................................................................1

1.1 Introduction..........................................................................................................................1

1.2 Problem Statement...............................................................................................................2

1.2.1The Concept.............................................................................................................................2

1.2.2 Situational Analysis................................................................................................................3

1.2.3 Site Analysis...........................................................................................................................4

1.3 Justification................................................................................................................................5

1.4 Objectives..................................................................................................................................5

1.4.1 General Objectives..................................................................................................................5

1.4.2 Specific Objectives.................................................................................................................5

1.5 Project Scope.............................................................................................................................6

CHAPTER 2....................................................................................................................................7

LITERATURE REVIEW................................................................................................................7

2.1 Water sources.............................................................................................................................7

2.1.1 Ground water sources.............................................................................................................7

2.1.2 Surface water sources.............................................................................................................8

2.2 Raw Water Treatment................................................................................................................8

2.2.1 Screening................................................................................................................................9

2.2.2 Aeration..................................................................................................................................9

2.2.3 Coagulation...........................................................................................................................10

2.2.4 Flocculation..........................................................................................................................10

2.2.6 Filtration................................................................................................................................15

2.2.7 Disinfection...........................................................................................................................16

2.2.9 Corrosion control..................................................................................................................19

2.2.10 Storage................................................................................................................................19

2.3 Factors Influencing the Water Supply Capacity......................................................................20

v

2.3.1 Design period........................................................................................................................20

2.3.2 Population Projection............................................................................................................20

2.3.3 Water Demand......................................................................................................................21

2.4 Generation of Concept Design.................................................................................................24

CHAPTER 3..................................................................................................................................25

THEORETICAL CONSIDERATIONS........................................................................................25

3.1 Population Data........................................................................................................................25

3.2.1 Human Population................................................................................................................25

3.2 Water Quality Samples............................................................................................................25

3.3 Design of Water Supply Facilities...........................................................................................26

3.3.1 Water Supply Intake Structure..............................................................................................26

CHAPTER 4..................................................................................................................................29

MATERIALS AND METHODS...................................................................................................29

4.1 Introduction..............................................................................................................................29

4.2 Data collection methods...........................................................................................................29

4.2.1 Questionnaires......................................................................................................................30

4.2.2 Interviews..............................................................................................................................30

4.2.3 Government Agencies...........................................................................................................30

4.2.4 Direct Observation................................................................................................................30

4.2.5 Sample..................................................................................................................................31

4.3 Data Analysis Methods............................................................................................................31

CHAPTER FIVE...........................................................................................................................32

RESULTS AND ANALYSIS........................................................................................................32

5.1 Population Data........................................................................................................................32

5.2 Field Investigation and Data Collection..................................................................................33

5:2:1 Raw Water Quality Sampling...............................................................................................33

5.2.2 Samples Testing....................................................................................................................33

5.3 Design of water Supply Features.............................................................................................37

5.3.1 Main pipe:.............................................................................................................................37

5.3.2 Flocculation..........................................................................................................................39

5.3.3 Sedimentation Tank..............................................................................................................40

5.3.3 Filtration Tank......................................................................................................................41

5.3.4 Chlorination Tank.................................................................................................................44

5.3.5 Storage Tank Capacity..........................................................................................................44

CHAPTER 6..................................................................................................................................46

DISCUSSION................................................................................................................................46

CHAPTER 7..................................................................................................................................47

vi

CONCLUSIONS AND RECOMMENDATIONS........................................................................47

7.1 Achievement of Objectives......................................................................................................47

7.2 Conclusions..............................................................................................................................47

7.3 Recommendations....................................................................................................................47

7.4 Challenges of Study.................................................................................................................48

REFERENCES..............................................................................................................................49

APPENDIX 1....................................................................................................................................i

Operational Definition of Terms......................................................................................................i

APPENDIX 2.................................................................................................................................. ii

A Map of the Nyansiongo Area.......................................................................................................ii

APPENDIX 3................................................................................................................................. iii

APPENDIX 4..................................................................................................................................iv

Sample I Raw water Test Results (Physiochemical analysis)........................................................iv

APPENDIX 5...................................................................................................................................v

Sample I Raw water Test Results (Bacteriology analysis)..............................................................v

APPENDIX 6..................................................................................................................................vi

Sample I Raw water Test Results (Physiochemical analysis)........................................................vi

APPENDIX 7................................................................................................................................vii

Sample I Raw water Test Results (Bacteriology analysis)............................................................vii

APPENDIX 8...............................................................................................................................viii

Sample III Raw Water Test Sample Results (physiochemical analysis)......................................viii

APPENDIX 9..................................................................................................................................ix

Sample III Raw Water Test Sample Results (Bacteriology analysis)............................................ix

APPENDIX 10................................................................................................................................xi

Budget and Workplan.....................................................................................................................xi

vii

LIST OF TABLES AND FIGURES

Figure 1: the amount of time it takes to fetch water (Nyamira-County, 2015)..........................4

Figure 2: Sketches of Raw Water Treatment Plant Process (Vasna, 2015)..............................9

Figure 3: Types of Flocculation and merits (Muya, 2005)......................................................12

Figure 4: Sedimentation tanks: Types, design criteria, Merits and Demerits.........................15

Figure 5: Backwash rates in relation to effective grain size...................................................16

Figure 6: population in the Nyansiongo Area.........................................................................31

Figure 7: physiochemical analysis of Sample 1.......................................................................32

Figure 8: Bacteriology analysis of sample 1...........................................................................32

Figure 9: Physiochemical analysis of sample II......................................................................33

Figure 10: Bacteriology analysis of sample II.........................................................................34

Figure 11: Physiochemical analysis of Sample III..................................................................35

Figure 12: Bacteriology analysis of Sample III.......................................................................35

viii

LIST OF ABBREVIATIONS

SDGs Sustainable Development Goals

UN United Nations

WHO

LVSWSB

World Health Organization

Lake Victoria South Water Services Board

ix

CHAPTER 1

INTRODUCTION

1.1 Introduction

Water is a basic need for humans and nature. The water sources can be classified as improved

or unimproved based on its quality. Improved water sources refer to those that are less prone

to contamination including boreholes, piped water, protected wells as well as harvested rain

water. Unimproved water sources are those that are prone to contamination, they include:

dams, lakes, djabia (traditional rainwater storage), unprotected wells, unprotected springs,

ponds water from rivers or streams, water vendors and other sources.

Raw water is water in its natural state or untreated water; it consists water from the

ground, infiltration wells water, and water from lakes and rivers, generally, water from

unimproved sources. Without treatment, raw water can be used for farming, construction or

cleaning purposes but not for domestic purposes such as drinking and cooking. In designing

the raw water treatment plant, factors such as the plant downtime, maintenance costs and if

the product (water) is fit for use have to be taken into account.

Sustainable Development Goal (SDGs) 6 is to ensure access to water and clean sanitation to

the entire population by 2030, the proportion of people in the world without access to

sustainable safe drinking water and basic sanitation is halved as agreed during 25 to 27

September 2015 New York Summit. In order to do this, it is necessary to provide access to

safe drinking water. This can be done through design and construction of various water

supply/distribution systems in the urban and rural areas, which deliver water safely free from

contamination e.g. piped water (AMCW, 2015).

In Kenya Vision 2030 under the social pillar, improved access to safe water and sanitation is

one of the priority targets. The 2030 vision for water and sanitation is to ensure that improved

water and sanitation are available and accessible to all. The goal for 2012 is to increase both

access to safe water and sanitation in both rural and urban areas beyond present levels. The

United Nations Human Settlement Programme (UN-Habitat) defines adequate water supply

as ‘a supply of water that is safe, sufficient, regular, convenient and available at an affordable

price. This design proposal targets to achieve the Kenya Vision 2030 goal which includes

improving water supply to citizens (WHO, 2016).

According to Kenya National Bureau of Statistics, 53% of the water sources in Kenya are

improved while 47 % is unimproved sources. The figures however indicate that in rural areas,

1

only 44% of the water sources are improved, 56% are unimproved, meaning, more people in

rural areas use water from unprotected sources. Nyansiongo Town, situated in Nyansiongo

Ward, Borabu Sub-County and Nyamira County is an upcoming market center. This has led

to mushrooming of people into the region as it has administrative roles as it is the

headquarters of the Borabu Sub-county. There is a thirsty demand for clean water services

since there is no piped water in the region as people depend on harvested rain water as well as

untreated sprigs for domestic use. This poses a health hazard as the people get prone to water-

borne diseases such as Typhoid(AMCW, 2015).

A raw water treatment system is a made up of several individual technologies that address

your specific raw water treatment needs. Treating raw water is rarely a static process, and a

raw water treatment system that is engineered to accommodate fluctuations in treatment

needs will go a long way in avoiding costly replacements/upgrades down the line.

A raw water treatment system should be efficient and well-designed to handle the seasonal

variations in turbidity and flow such as during the long rains and short rains, variations in

water chemistry needs and required chemical volumes adjustments. The system depends on

the quality of water being drawn from in relation to the quality of water needed, but in

general, a basic raw water treatment system typically includes some type of chemical feed to

help facilitate the flocculation or coagulation of any unsuspended solids, clarifier to settle out

the larger solids, filtration to remove the smaller particles and a control panel (depending on

the level of automated operation needed). Depending on the needs of your plant and process,

these standard components are usually adequate, however, if your plant requires a system that

provides a bit more customization, there might be some features or technologies you will

need to add on

1.2 Problem Statement

1.2.1The Concept

Monitoring Programme’s 2012 report, access to safe water supplies throughout Kenya is 59%

and access to improved sanitation is 32%. There is still an unmet need in rural and urban

areas for both water and sanitation. In a bid to counter problems like rural to urban migration,

social amenities including access to clean, and safe tap drinking water should provide to rural

areas too. However over the past years, Nyansiongo Town has grown immensely in

population. This has brought up the need for better infrastructure and social amenities like

schools, hospitals and market centres to cater for the large population (WHO, 2016).

2

The water supply in the area needs to be upgraded to meet the ever increasing demand from

both the domestic and industrial use. The area is currently supplied with water from streams

and also through rain harvesting. This presents a challenge because the underground water is

not adequately treated to meet the required WHO drinking water standards. The water from

the streams is majorly from un-improved sources which makes it more prone to pollution

from the rainwater and so it does not meet the recommended Drinking Water Quality

Standards for Kenya. This poses as a health risk to the users. There was therefore need to

source out another water source that would be reliable and provide safe water for

consumption (WHO, 2016).

1.2.2 Situational Analysis

Nyamira County is generally not a water scarce country, as it is located on the Kisii

Highlands with a fair Distribution of rainfall throughout the year. The county has 7

permanent rivers, 1,945 shallow wells, over 3,301 unprotected springs, 2,521 protected

springs and 694 dams. In 2009, 4403 households which reflects just 3.4% had access to

portable water as per the Population and House Census. Approximately, the nearest water

points are located within 0-4km from the households. Mostly it’s the women and girls who

fetch water from streams and water points denying them an opportunity to engage in more

constructive economic activities such as studying. Only 3.4% of the people have access to

piped water, on average, 7.8 % of households take approximately 1min-4min to fetch water,

5-14 minutes is taken by 2.4%, almost half the population(49.2%) take between 15-29 min,

30.5% of the population take 30-59 minutes while 13.4% take more than an hour to fetch

water. This majorly happens during the drier months moreso to the people who stay up the

hilly considering the terrain in Kisii land (Nyamira-County, 2015).

In-order to enhance progress in other sectors, it’s critical to improve and protect the county

water sources. It’s important to equally improve the agricultural subsector to stop over

relying on rain-fed agriculture by harnessing water hence increasing land under irrigation.

Primarily, the region depends on its natural base. Increasing access to sustainable water is a

priority of the government within the existing policy framework. Some of the main

challenges facing improvement of access to water resources include: inadequate funds, the

planting of blue gum trees at riverbanks and springs and lack of local ownership for the

projects.

3

There has been concerns about water in Nyamira County, a move that has facilitated the

building of Itibo dam at 5Billion Kenyan shillings so as to supply water for the people at

Nyamira Town though this cuts out other developing towns such as Nyansiongo (Ongwae,

2017). This happened at the awaken of the longer droughts experienced with fewer rains due

to climate change across the country. The Lake Victoria South Water Services Board

(LVSWSB) has noted out several wetlands for improvement that shall lead to proper

increased water generations and therefore NB: only 3.4% of the population have access to

piped water.

Time taken to fetch water (minutes) 1-4 5-14 15-29 30-59 Over 60

Population percentage 7.8 2.2 49.3 30.5 13.4

NB: only 3.4% of the population have access to piped water.

Figure 1: the amount of time it takes to fetch water(Nyamira-County, 2015)

1.2.3 Site Analysis

Location

Nyamira County one of the forty seven counties in Kenya located in the western side of

Kenya. It has three major towns which include, Nyansiongo, Nyamira and

Keroka.Nyansiongo town is located along the Kisii-Nairobi Highway and it serves many

purposes amongst, administrative unit as it is theheadquarters of the Borabu Subcounty and

Borabu District, as well as hosting Nyansiongo Tea Factory. It stands at an altitude of 1500

meters ASL and has a warm moderate climate. Its coordinates are 35 0.9’ East and 0 0.45’

South (226201.9 Easting, 3877156.7 Northings).The region equally has one permanent river,

Kijauri River-that is all seasoned and some other streams. The water from Mosiabano dam is

used by the Nyansiongo Tea Factory for cleaning purposes now that tea processing is majorly

a dry process.

Soil conditions

The soil in the area is mainly red acidic volcanic soils (Nitosols)which are deep, fertile and

well drained; that are good for agriculture but expensive when it comes to road construction

and maintenance.From reconnaissance survey, it’s swampy in the area along Mosiabano dam

and so the soils around the dam are clay soils, (Nyamira County Annual Development Plan

2014/2015, 2015)

4

Climate

Nyansiongo receives on average 1200mm - 2100mm of rainfall per annum. The region has no

distinct dry spell separating the long and short rains that start in December to June and July to

November respectively. The average normal temperature is 19.40, which is an average of

maxima and minima of 28.70C during the day and 10.10C at night, which isfavorable for both

agricultural and animal farming.The temperature averages 16.1 °C, (Nyamira County Annual

Development Plan 2014/2015, 2015).

Site Conditions

From the assessment of the area during the reconnaissance survey, it was found out that the

road leading to the dam is a murram road. Roads are of importance in ensuring smooth flow

of farm inputs, farm produce of the farmers and the management of the Mosiabano Dam.

The land where the dam is located is owned by the Kenyan Government. Most of the land use

in the area is farming. There are residential places around as well as the Tea Factory that

majorly uses the water for the dam for cleaning purposes.The main economic activities of the

neighboring community is farming. There is equally a tea Factory, and administrative units a

few meters from the dam, a region that has grown from just being a market centre, to the

headquarters of Borabu Distric and Borabu Sub County. Despite these eminent positive

reflections of the town and rise in status to a District, this town has no comprehensive raw

water treatment, distribution, and sewerage connection or sewer treatment plant so far.

1.3 Justification

The main water sources of Nyansiongo town are springs rainwater harvesting which are not

sustainable throughout the year. Mosiabano dam, located at the outskirts of Nyansiongo

Town, is a probable source of water to its neighborhood but it’s not safe for consumption due

to its untreated nature and lack of a treatment plant. If the raw water treatment system is

done, then water distribution system design is done, there will be improved health, improved

quality water for domestic use, improved time spent in studies and other economic benefiting

activities in the region and beyond among the residents of Nyansiongo Town. The treatment

works will be sited in a place such that it will be at a higher region therefore supplying water

by gravity to the area of demand. This will eliminate the need for the extra cost of pumping

of water to the region. It shall also help the country in realization of a part of Vision 2030 as

well as the Sustainable Development Goals.

5

1.4 Objectives

1.4.1 General Objectives

The overall objective of this project will be to design a raw water treatment system at

Mosiabano dam, at Nyansiongo Ward in Nyamira County.

1.4.2 Specific Objectives

The specific objectives of the study are to:

1. Determine the water utilization/demand in Nyansiongo area.

2. Evaluate raw water quality from Mosiabano Dam.

3. Determine the specifications for Mosiabano dam raw water treatment works and

related components

1.5 Project Scope

This project will mainly deal with design of the raw water intake pipes and treatment process,

which includes planning, designing and construction, but the ‘project is limited to the design

of the raw water treatment plant at Mosiabano dam in Nyansiongo Ward, Borabu

Constituency, Nyamira County. The project will determine the actual water demand of the

Nyansiongo Town, size of the raw pipes from the reservoir to intake treatment works, test on

the quality of water from Mosiabano Dam, design of a raw water treatment works as well as

drawing of the treatment works with AUTOCAD.

6

CHAPTER 2

LITERATURE REVIEW

2.1 Water sources

All sources of freshwater always originate from rainfall. Rainfall is slightly acidic due to

dissolution of carbon dioxide in the atmosphere. As surface run off, it gathers considerable

amounts of soil particles mineral matters and organic matter, microorganisms, etc. When

surface runoff infiltrates into subsoil level it forms ground water. As the ground level water

increases due to varying land formations, it oozes out as springs. Perennial springs are the

fountain heads of surface water bodies such as streams, rivers and lakes. Therefore, water can

broadly be classified into two, ground water and surface water

2.1.1 Ground water sources

These are the sources that tap their water from ground aquifers in the underground rocks or

strata. The aquifers are water yielding rocks normally in between two impervious rocks or an

impervious and pervious rock. The aquifers are actually water reservoirs which retain water

that has trickled through the pervious or impervious rocks formation commonly termed as

water table.

Water tables that are formed in between impervious rocks are in most cases deep and are

permanent water sources while those that form between pervious and impervious rocks are

shallow and are seasonal water suppliers. The ground water sources include:

Springs

Springs are naturally occurring water source that emerge from the ground. They mainly occur

in hilly, mountainous areas and river valleys. The two types of springs include:

a.) Gravity springs: Occur where ground water emerges at the surface because an impervious

layer prevents it from seeping downwards. This happened when an unconfined aquifer

emerges into the open. It occurs on sloping ground. The flow depends on the water table.

b.) Artesian springs: Occurs where ground water emerges at the surface after confinement.

The flow is very nearly constant.

Wells

Water well is an excavation created in the ground to access water in the aquifers. They

greatly vary in depth depending on the water table. The diameter of such excavations

determines whether it is a borehole or a well; wells have larger diameters than boreholes. It

7

can be excavated by digging, driving, boring or drilling to the water table. The wells can

either be:

a.) Shallow wells: Manual digging can be used to excavate wells to reach the aquifer. Their

diameters are large enough to accommodate well diggers with their tools. They can be dug up

to a depth of 20-30m usually in loose soils by hand.

b.) Deep wells: These are normally excavated by drilling or by driving methods. The depth

normally ranges from 6 -180m deep depending on the level of the water table.

2.1.2 Surface water sources

Surface water refers to from the lakes, reservoirs, rivers and streams. These water bodies are

formed of water from direct rain, runoffs, and springs. A runoff is the part of rain water that

does not infiltrate the ground or evaporate. It flows by gravity into the water body from the

surrounding land. The total land area that contributes surface runoff to a river or lake is called

a watershed, drainage basin, or catchment area.

The volume of water available for municipal supply depends mostly on the amount of

rainfall. It also depends on the size of the watershed, the slope of the ground, the type of soil

and vegetation, and the type of land use.

The surface water sources are easily susceptible to contamination due to careless human’s

behavior of littering, contamination by animals as well as environmental effects such as

winds that blow up dirt onto the surfaces and flash floods. That’s why it’s very important to

treat the water from surface sources so that they can be deem fit for use by the human beings.

2.2 Raw Water Treatment.

Natural surface waters contain inorganic and organic particles. Inorganic particles such as

clay, silt, and mineral oxides, typically enter surface water by natural erosion processes.

Organic particles may include viruses, bacteria, algae, protozoan cysts and oocyst, as well as

detritus litter that have fallen into the water source. Conventional water treatment is a multi-

phased process. The phases consist of raw water intake, optional pretreatment, flash mixing,

coagulation, flocculation, sedimentation, filtration, disinfection, corrosion control, and

laboratory analysis. These phases are common to all conventional treatment facilities.

8

Figure 2: Sketches of Raw Water Treatment Plant Process(Vasna, 2015)

2.2.1 Screening

Floating debris such as woods, leaves, aquatic plants and others are screened at the intake.

After screening, the denser suspended matters are removed by allowing water to pass through

chamber where it settles down to the bottom. The basin screens out large debris and settles

out sand and silt. Surface water will initially pass through screens to ensure that large debris

does not damage pumps and other equipment. The water may be dosed with chlorine or other

chemicals to remove potential odours, to kill algae, or to control zebra mussels [Punmia et al,

2009].

2.2.2 Aeration

Raw water pumped from the intake is mixed with air at the aerator. The aeration process

provides oxygen from atmosphere for the oxidation of dissolved iron and manganese to their

9

insoluble form thus enables their removal. The process also helps in the removal of taste and

odour.

2.2.3 Coagulation

Involves the addition of a chemical coagulant or coagulants for the purpose of conditioning

the suspended, colloidal, and dissolved substance for subsequent processing by flocculation

or to create conditions that will allow for the subsequent removal of particulate and dissolved

matter. It involves the addition of compounds such as aluminium sulphate (alum) and iron

salts, organic polymers and sometimes lime and carbon dioxide. Raw water will contain

small particles, known as colloids. These colloids produce a cloudy appearance known as

turbidity. Turbidity can shield micro-organisms from disinfection. This process causes small

particles to stick to one another, forming larger particles. The water is mixed at high speed

while alum is added to chemically combine with contaminants and neutralize the electrical

charges. This allows the impurities to begin coagulating, or forming small particles that can

more easily be removed [Twort et al, 2004].

2.2.4 Flocculation

Refers to the aggregation of destabilized particles (particles from which the electrical surface

charge has been reduced) and precipitation products formed by the addition of coagulants

into larger particles known as flocculants particles or, more commonly, ‘‘floc.’’ The

aggregated floc can then be removed by gravity sedimentation and/or filtration. The purpose

of flocculation is to produce particles, by means of aggregation, that can be removed by

subsequent particle separation procedures such as gravity sedimentation and/or filtration. The

two general types of flocculation can be identified: (1) Micro-flocculation (also known as

perikinetic flocculation) in which particle aggregation is brought about by the random

thermal motion of fluid molecules (known as Brownian motion and (2) Macro-flocculation

(also known as orthokinetic flocculation) in which particle aggregation is brought about by

inducing velocity gradients and gentle mixing in the fluid containing the particles. Mixing for

flocculation generally lasts for 20 to 40 min [Crittenden et al, 2012].

10

Table 1: Types of Flocculation and merits

Comparison to basic approaches to flocculation

Process issue Horizontal shaft with

paddles

Vertical shaft

turbines

Hydraulic

flocculation

Type of floc

produced

Head loss

Operational

flexibility

Capital cost

Construction

difficulty

Maintainance effort

Compartmentalizatio

n

Large and fluffy

None

Good, limited to low

G

Moderate to high

Moderate

Moderate

Moderate

compartmentalization

Small to medium,

dense

None

Excellent

Moderate

Easy to moderate

Low to moderate

Excellent

compartmentalizatio

n

Very large and fluffy

0.05-0.15m

Moderate to poor

Low to moderate

Easy to moderate

Low to moderate

Excellent

compartmentalizatio

n

Advantages Produces large floc.

Reliable.

No head loss.

One shaft for several

mixers.

No head loss.

Very flexible and

reliable

Highest energy input

potential

Flocculators can be

maintained without

shutdown.

Simple and effective.

Easy, low cost

maintainace.

No moving parts.

Can produce very

large flocs.

Little flexibility.

Disadvantages Compartmentalizatio

n more difficult.

Replacement and

maintainance require

Difficult to specify

proper impellers and

reliable gear drives

Little flexibility

11

shutdown.

Shaft breakage on

start up because of

high initial torque.

Figure 3: Types of Flocculation and merits(Muya, 2005)

2.2.5 Sedimentation

If turbid waters are placed into a large quiescent basin and left over time, the suspended

material can settle to the bottom of the basin. Particles settle out of solution because they are

large enough to settle out by gravitational forces. This process is called sedimentation. Most

raw surface waters contain mineral and organic particles. Mineral particles usually have

densities ranging from 2000 to 3000 kg/m3 and will settle out readily by gravity, whereas

organic particles with densities of 1010 to 1100 kg/m3 may require a long time to settle by

gravity. Depending on their density, suspended particles larger than 1μm can be removed by

sedimentation [Howe et al, 2012].

The simplest form of sedimentation basin is a large, open structure where the water can flow

through quiescently. As water flows through the basin, particles settle to the bottom, where

they form a sludge layer that is pushed by mechanical scrapers to a collection trough and

removed.

The larger suspended particles (floc) formed in the flocculation basin settle to the bottom of

the basin. Inclined plates are used to speed the settling. Clear water is skimmed off the top of

the basin. A well-designed inlet permits water from the flocculation basin to enter directly

into the sedimentation basin without channels or pipelines.

A diffuser wall is one of the most effective and practical flow distribution methods used at

the basin inlet when the flocculation basin is directly attached to the sedimentation basin. A

diffuser wall is simply a wall with many small holes strategically placed to uniformly

redistribute the flow of water.

For uniform distribution of raw water the openings should be spaced close to each other less

than 0.5m apart, and their diameter not less than 50mm. The draw-off should be made over at

least 25% of the length of a horizontal tank. The effluent water should leave the tanks over a

weir whose level is adjustable about 30mm or through a submerged perforated pipe. The total

12

length of the weir in meters should be at least 0.1 x A where A is the surface area of the

sedimentation tank in square meters. When filtration succeeds flocculation the outlet velocity

from the sedimentation tank should not exceed 0.4 m/s in order not to destroy residual flocs

[Water Design Manual Kenya, 2005].

The ratio length/width should be between 3:1 and 6:1 and the effective water depth should be

at least 2m. There should be an additional volume of 25% to allow for sludge accumulation.

The tank floor should slope gently (2-3%) towards a pocket placed at 1/4 to 1/3 of the length

of the tank from the inlet side [Water Design Manual Kenya, 2005].

The basic design criteria to be considered for the horizontal-flow settling zone are (1) surface

loading rate, (2) effective water depth, (3) detention time, (4) horizontal-flow velocity, and

(5) minimum length-to-width ratio.

13

Table 2: Sedimentation tanks: Types, design criteria, Merits and Demerits

TYPICAL

APPLICATION

DESIGN CRITERIA MERITS DEMERITS

Rectangular Basin(horizontal flows)

Municipal and

industrial works.

Suited to large capacity

plants.

Surface loading: 1.25-

2.5m/h

Water depth:3-5m

Detention time 1.5-4h

Minimum length to

width ratio 4:1 to 5:1

Weir loading <9-

13m2/h

More tolerance to

shock loads.

Predictable

performance under

most conditions.

Easy operations and

low maintainace costs.

Easily adapted for high

rate settler modules.

Subject to density flow

creation in basin.

Requires careful design

of inlet and outlet

structures.

Requires separate

flocculation facilities.

Upflow ( Radial Flow)

Small to midsize

municipal and

industrial water T

works.

Suited where rate and

raw water quality flow

is constant.


1.88m/h

Water depth:3-5m

Settling time 1-3h

Weir loading 170

m3/m.d

Economic Compact

Geometry.

Easy sludge removal.

High clarification

Efficiency.

Problems of flow short

circuiting.

Less tolerance to shock

loads.

Need for more careful

operations.

Limitation of more

practical size.

May require separate

flocculation facilities.

Solid Contact Clarifiers

Water Softening.

Flocculation-

Flocculation time

20min.


Good softening and

turbidity removal.

Sensitive to shock

loads and changes in

flow rate.

14

sedimentation

treatment of raw water

that has constant

quality and rate of

flow.

Plants treating raw

water with low solid

concentration.

3.1 m/h

Detention time 1.5-4h

.

Weir loading 175-350

m3/ m.d

Up flow velocity

<10mm/min

Flocculation and

clarification in one unit.

Compact and economic

design.

Sensitive to

temperature changes.

Plant operation

dependent on single

mixing motor.

Higher maintainace

cost and greater

operational skill

required.

Figure 4: Sedimentation tanks: Types, design criteria, Merits and Demerits

2.2.6 Filtration

The water is then filtered through layers of fine, granulated materials — either sand, or sand

and coal, depending on the treatment plant. As smaller, suspended particles are removed,

turbidity diminishes and clear water emerges. Removing as much suspended particles as

possible is very important for the operation of a treatment facility. Not only will the water

appear clean to the consumer, but removing suspended particles eliminates the possibility of

dangerous bacteria being protected from the disinfection process.

The most common type of filtration process is known as the rapid sand filtration. Although

there are various types of various sand filters, most operate using the same general principles.

These filters normally contain layers of anthracite, sand, and/or gravel. The tiny pore spaces

in the filter "media" trap the suspended particles. Most matter which has not settled in the

flocculation tank is entrapped by the filter media. Activated carbon may also be used to

remove taste and odour problems. The quality of the water, as it leaves the filtration process

can be determined by its turbidity. High turbidity may indicate that the filters require

cleaning.

Filters are cleaned on a regular basis (usually 1-4 days depending on the facility) by a process

known as backwashing. During this process the normal water flow is shut off and fully

treated water is pumped up, backwards, through the filter media to remove the entrapped

matter. The backwash water will be further treated to remove the solids or routed to the

sanitary sewer [Punmia et al, 2009].

15

Design details for final filters succeeding sedimentation (Muya, 2005)

Each filter unit should have individual inlet that can be closed for servicing and

backwashing. It should be such that flushing and velocities 0.4 m/s does not occur.

Backwashing: The backwash rates depend on grain size of filter media and should be

in with table below.

Table 3: Backwash rates in relation to effective grain size

Effective grain size of filter, mm Backwash rates m3/m2h

0.5 25

0.6 30

0.7 40

0.8 50

0.9 60

1.0 70

Figure 5: Backwash rates in relation to effective grain size

Backwash outlet system should be designed to a minimum backwash rate of

50m3/m2h despite calculation rate being lower.

For calculation, the amount of water for backwashing is assumed to be for a period of

8minutes.

2.2.7 Disinfection

This is an essential element of the overall strategy for providing water that is safe to drink.

Providing water free from pathogenic organisms is accomplished using several

complementary strategies:

(1) Selecting a water source that is free from microbiological contamination.

(2) Protecting surface water sources to minimize microbiological contamination.

(3) Treating water to remove microorganisms or eliminate their pathogenicity.

(4) Preventing recontamination of water as it is delivered to customers through the

distribution system

16

Surface waters, however, virtually always contain pathogenic organisms and must be

disinfected. Many different types of microorganisms can be present in surface water, but for

purposes of disinfection they can be grouped in broad classes that include viruses, bacteria,

and protozoa.

Five disinfection agents are commonly used in drinking water treatment today: (1) free

chlorine, (2) combined chlorine (chlorine combined with ammonia, also known as

chloramines), (3) chlorine dioxide, (4) ozone, and (5) ultraviolet (U.V) light. The first four

are chemical oxidants, whereas UV light involves the use of electromagnetic radiation [Dr

B.C Punmia et al, 2009].

Designing a disinfection system includes three primary activities:

(1) Selecting a suitable disinfectant and dose.

(2) Designing a system to inject or introduce the disinfectant into the water.

(3) Designing contactors that provide a sufficient amount of time for the disinfectant

reactions to take place.

Currently, there is no single disinfectant which satisfies all the above mentioned criteria.

Even chlorine once considered to be free of any adverse health effect has shown its

limitation. Disinfectant doses depend on whether the disinfectant is being used for

inactivation, residual maintenance, or both. When chemical disinfectants are added to water,

some of the chemical will be consumed during rapid oxidation of reduced compounds in the

water; this consumption is known as the initial demand. Once the initial demand has been

satisfied, additional chemical addition leads to a residual concentration in the water.

To protect against any bacteria, viruses and other microbes that might remain, disinfectant is

added before the water flows into underground reservoirs throughout the distribution system

and into your home or business. Denver Water carefully monitors the amount of disinfectant

added to maintain quality of the water at the farthest reaches of the system. Fluoride occurs

naturally in our water but also is added to treated water. [Howe et al, 2012]

1. Chlorination

17

It’s the process of adding of chlorine and chlorine compounds in water is called chlorination.

Chlorine is commercially available in three forms: liquid, powder and liquefied compressed

gas. Chlorine in its various forms is widely used to disinfect drinking water. This is attributed

to its cost, ease in application and adaptability to different environment. The majoradvantage

of chlorination is the residual chlorine in the distribution network and storage, which provides

protection against recontamination and microbial after growth.

On addition of chlorine to pure water, it produces hypochlorous acid (HOCL) and

hypochlorite ion (OCL-), which are the actual disinfecting agents. The reaction depends on

pH and temperature of the water. The disinfecting capacity is retained in HOCL, and it is

regarded to be greater than OCL-. It has been shown that HOCL kills 80 – 100 times more

E.coli than OCL-.

Cl2 + H2O -> HOCl + H+ + Cl-

Depending on the pH value; underchloric acid partly expires to hypochlorite ions:

Cl2 + 2H2O -> HOCl + H3O + Cl-

HOCl + H2O -> H3O+ + OCl-

2. Ozonation

Ozonation is the method of diffusing ozone, an allotropic form of oxygen into the water for

the purpose of disinfection. The inherent instability of ozone to decompose back to oxygen

necessitates its production on site for immediate use. It is produced by passing an electric

discharge of high voltage alternating current through the dry air. In the generation process, a

power voltage of 4-20 kilovolts is applied to dielectric plates about 6mm apart or to

concentric tubes through which clean, dry oxygen rich gas is blown. The amount produced

may be up to 30 mg/m3 of the blown air. The generation process, the need of skilled

manpower for operation and maintenance leads to higher cost. These disadvantages hinder its

adoption in developing countries.

Ozone is also used for taste and odour control, colour removal and oxidation of iron and

manganese and organic removal. When using ozone as a disinfectant the recommended

dosage is 0.2 – 1.5 mg/L.

Ozonation as a disinfectant has the following benefits: -

• Highly effective disinfectant in destroying pathogenic bacteria and viruses.

18

• More effective in disinfecting water containing ammonia than chlorine.

Ozone’s ability to decompose organic matter may cause problems in the network due to

increasing volume of bio-assimilable compounds, unless the degradation products are

removed or an additional disinfectant with a long term effect is used [Practice Manual for

Water Supply Services in Kenya, 2005].

3. Ultra-violet Radiation

The UV rays are part of the electromagnetic spectrum between x-rays and visible light. The

most common source of UV radiation is the coated mercury low pressure lamp. This type of

lamp is mostly used in existing UV plants for disinfection purposes. To achieve the

maximum efficiency the lamps must be kept clean so that the organisms are exposed to the

full intensity of the UV light.

Disinfection is accomplished when the water is exposed to the UV light source. For effective

disinfection, the water must be without turbidity or colour and free from organic colloids that

might form deposits on the tubes or obstruct the passage of light. Also the depth of water

must be shallow.

Because the UV radiation leaves no residual, the disinfection has to be complimented either

with chlorine or chlorine dioxide. The shortcomings coupled with the hardware problems

make UV unfeasible in developing countries [Practice Manual for Water Supply Services in

Kenya, 2005].

2.2.9 Corrosion control

pH is maintained by adding high pH substances to decrease corrosion in the distribution

system and the plumbing in your home or business. Corrosion inhibitors such as calcium are

added to increase the service life of the piping throughout the distribution system [Practice

Manual for Water Supply Services in Kenya, 2005].

2.2.10 Storage

Treated water from the retention tank will be collected and kept in a clean dark tank to

prevent the growth of algae the tank si small in size and makes sure that the water is safe for

domestic use. Residual chlorine is used or more chlorine is added. This is to act as a

disinfectant according to safety regulations. Fluoride may be added to enhance dental health.

In addition, Lime and carbon dioxide may be added to make the water less corrosive to home

plumbing systems [Punmia et al, 2009].

19

2.3 Factors Influencing the Water Supply Capacity

The major objective of water supply system is to supply adequate water for a town which is

adequate water for domestic, commercial, industrial and livestock use. Therefore a selected

for a suitable should be selected and the other alternative should be studied and compared

technically and also from economic point of view. The design population, period, topography

of the area and construction cost of transmission lines should be considered in details.

2.3.1 Design period

Design period is also called the design life. It is the number of years in future for which the

given facility is available to meet the demand. Design period is provided because it is very

difficult or impossible to provide frequent extension. It is also cheaper to provide a single

large unit rather to construct a number of small units. The design period is the length of time

it is estimated that the facility will be able to meet the demand that is the design capacity.

Buildings, other structures, and pipelines are assumed to have a useful life of 50 years or

more. See appendix VI for design period table.

2.3.2 Population Projection.

Population projections are estimates of the population for future dates. For the water supply

system population should be estimated based on latest census in this case will be 2009.

Design of water supply and sanitation scheme is based on the projected population of a

particular city, estimated for the design period. Any underestimated value will make system

inadequate for the purpose intended; similarly overestimated value will make it costly.

Changes in the population of the city over the years occur, and the system should be designed

taking into account the population at the end of the design period.

Factors affecting changes in population are: -

• Increase due to births.

• Decrease due to deaths.

• Increase/decrease due to migration.

• Increase due to annexation.

The present and past population record for the city can be obtained from the census

population records. After collecting these population figures, the population at the end of

20

design period is predicted using various methods as suitable for that city considering the

growth pattern followed by the city.

a) Linear Increase

It implies that there is a constant amount of increase per unit of time. A straight line is used to

project population growth. This method is suitable for large and old cities with considerable

development. If it is used for small, average or comparatively new cities, it will give lower

population estimate than actual value. It is expressed as:

Pt=P0+bt…………………...Eq 1

Where: P0 – initial population at present.

Pt – population after t years

b – Annual amount of population change

b) Geometric Increase

According to this method, it is assumed that the rate of increase of population growth in

communityis proportional to the present population. In this method the percentage increase in

population fromdecade to decade is assumed to remain constant. Geometric mean increase is

used to find out thefuture increment in population. Since this method gives higher values, it

should be applied for anew industrial town at the beginning of development for only few

years.

Pn=P0 (1+r )n………………..Eq 2

Where: Pn- population after n years.

Po- Population at the present.

R- Annual population growth rate.

c) Exponential Increase Method

The method is based on the assumption that percentage growth rate is constant i.e.

dPdt

=kP ; lnP=ln P0+kt………………Eq 3

The method however must be used with caution, as it may produce results that are too large

for rapidly growing cities in comparatively short time. This would apply to cities with an

unlimited scope of expansion [Source].

2.3.3 Water Demand

Water demand varies for the different uses. These can be classified as follows:

i. Domestic or Residential demand

21

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB0QFjAAahUKEwitioHax_HIAhXEPRQKHcDaC-w&url=http%3A%2F%2Fnptel.ac.in%2Fcourses%2F105105048%2FM5L5.pdf&usg=AFQjCNHYc9dZ1-PEdX3hJm_S4TwHlK8u8g&sig2=odwMl5Gnt7vphejsOe8omQ

This includes water used required in private building for drinking, bathing, gardening,

sanitary purpose etc. it is influenced by population density and service type (depends on

whether an individual is connected or not).

ii. Industrial demand

It represents the water demand of industries which earlier exist or are likely to be started in

future. Water used for industrial purposes may be incorporated into products or used for

processing, washing, cooling, sanitation, or maintenance. Industries are categorized into bar,

shops, restaurants, large enterprises, military camps etc.

iii. Commercial demand

This is the water requirement for institutions, hotels, schools, health facilities, colleges and

offices. It should be anticipated that the future increase in commercial activity would be

directly related to the growth of population.

iv. Fire demand

In populated or industrial areas, fires generally breakout and may lead to damage. For control

that situation requires sufficient quantity of water which is the fire demand.

v. Livestock demand

Includes water associated with the production of meat, milk, poultry, eggs, and wool. The

kind of stock includes dairy cows and heifers, beef cattle and calves, sheep and lambs, goats,

hogs and pigs, and poultry. Poultry includes chickens, turkeys, ducks, geese, pheasants, and

pigeons. (Hutson et al, 2004). Usually estimating water livestock demand the following

conversion factor is used: 1 grade cow; 3 indigenous cows; 15 sheep or goat and 100

chickens are equivalent to one livestock unit (LU).

2.3.4 Losses

Every water supply has a portion of ‘” unaccounted for” water which includes:

Consumer wastages, leakages and wastage from consumer premises.

Distribution losses, leakages from mains, service pipes and service connections,

valves, hydrants and wash outs.

Metering and other losses, unauthorized and unrecorded connections.

Treatment works usage and overflow at reservoirs.

22

Water demand projections should normally be made for the “initial”, the “future” and the

“ultimate” year. The “initial” year is the year when the supply is expected to be taken into

operation that may be assumed to be 0-5 years from the date of the commencement of the

preliminary design. The “future” is 10 years and the “ultimate” year 20 years from the initial

year. Once the initial, future and ultimate years have been determined for a project they

should not normally be changed during the design period. However phasing of the

implementation will often become a financial necessity and the possibilities of phasing

should therefore be examined using the initial and future demand projections. (Water Design

Manual, 2005 Kenya).

23

2.4 Generation of Concept Design

24

Problem Identification

Lack of supply of clean, safe and reliable water

Change in Weather and climatic part

Problem analysis

Desk study carried out to understand the problem fully and identify possible causes

Solution Development

Several water supply methods were studied in great depth to identify the best method to be used. The selected method was chosen based on

Economical Viability Social acceptability Technical feasibility

CHAPTER 3

THEORETICAL CONSIDERATIONS

3.1 Population Data

3.2.1 Human Population

After collecting these population figures, the population at the end of design period is

predicted using various methods as suitable for that city considering the growth pattern

followed by the city.

a) Geometric Increase

Based on the hypothesis that rate of change of population is proportional to the population.

According to this method, it is assumed that the rate of increase of population growth in

community is proportional to the present population. In this method the percentage increase

in population from decade to decade is assumed to remain constant. Geometric mean increase

is used to find out the future increment in population. Since this method gives higher values,

it should be applied for a new industrial town at the beginning of development for only few

years.

Pn=P0 (1+r )n………………..Eq 2

Where: Pn- population after n years.

Po- Population at the present.

R- Annual population growth rate.

The values of demand will be used together with the projected population to generate the

quantity of water demand as shown below. The quantity of water demanded is obtained from

the formula:

Wa ter Demand=per capitademand x population

3.2 Water Quality Samples

The criteria used for determining the frequency of sampling in the guidelines (Water Services

Regulatory Board) include:

1. Source of the water - whether ground or surface water;

2. Volume produced and Population served;

3. Number of tests to be conducted – both bacteriological and physiochemical

25

Identification of strategic sampling points within the distribution system is important in

ensuring that these are representative of the entire system and at the same time ensuring that

particular problem areas are identified.

In selecting sampling points, the following general selection criteria should be taken into

consideration:

a) Samples taken have to be representative of the different sources from which water is

obtained by the consumers or enters the system

b) Sampling points should include the most unfavorable sources or places in the supply

system, particularly points of possible contamination such as unprotected sources,

loops, reservoirs, low-pressure zones, ends of the system etc.

c) Sampling points should be uniformly distributed throughout a network.

3.3 Design of Water Supply Facilities

3.3.1 Water Supply Intake Structure

a. Trunk Main Pipe Size

Volume flow, Q = volume(m3)/Time(sec)

Elevation at the raw water intake, H1

Elevation at the treatment water works site, H2

Change in elevation, ∆H= H1-H2

Distance between the intake and the T works, (total length of the pipe), L

Pipe roughness coefficient=150 from the Hazel Wiliiams Chart

Using Hazen-Williams equation (majorly used in determination of friction losses) to obtain

pipe diameter, D

∆ H =10.7 L ×Q1.852

C1.852× D4.87

The head loss can be verified by using Darcy Weisbach equation:H f =fLV 2

D× 2g

Where:

Hf = head loss (m)

26

f = friction factor

L = length of pipe work (m)

d = inner diameter of pipe work (m)

v = velocity of fluid (m/s)

g = acceleration due to gravity (m/s²)

b. Flocculation Tank Calculations

The general design criteria for a basic rectangular flocculation tank are as follows:

Energy input: Gt=10,000 to 100,000,

t =5x104 s average,

G=30 s-1 average, 10-70 range

DT: 20-30 minutes at Qmax. (Design Time)

Depth: 10-15’

Stages: 3-4 common, 2-6 range

The energy level is the G value or velocity gradient as defined by Camp: G = [P /V]2

The number of particle contacts is: N = n1n2(G/6)(d1 + d2)3

N is the number of contacts between n1 and n2 particles.

c. Sedimentation tank

Detention period: for plain sedimentation: 3 to 4 h, and for coagulated sedimentation: 2 to 2.5

h.

Velocity of flow: Not greater than 30 cm/min (horizontal flow).

Tank dimensions: L:B = 3 to 5:1. Generally L= 30 m (common) maximum 100 m. Breadth=

6 m to 10 m. Circular: Diameter not greater than 60 m. generally 20 to 40 m.

Depth 2.5 to 5.0 m (3 m).

27

Surface Overflow Rate: For plain sedimentation 12000 to 18000 L/d/m2 tank area; for

thoroughly flocculated water 24000 to 30000 L/d/m2 tank area.

Slopes: Rectangular 1% towards inlet and circular 8%

d. Chlorination Tank

Using a chlorine dose of 2mg/l; (which conforms to the WHO water standards which requires

that 2-3mg/l of chlorine should be added in order to gain satisfactory disinfection and residual

concentration)

e. Storage Tank Capacity

The required total storage capacity of a reservoir capacity is the summation of: balancing,

breakdown and fire reserve. The balancing reserve can be estimated from data of hourly

consumption of water for the town. Due to the unavailability of this data, the storage capacity

is assumed to be 1/8 of the total daily water demand i.e. the storage water tank will be able to

store 1/8 of the quantity of water processed at the treatment plant per day.

28

CHAPTER 4

MATERIALS AND METHODS

4.1 Introduction

In establishing the water utilization/demand in the area various data like population data,

livestock data, use of water data, need for water data, water samples-industrial and

institutional data was required. This data was obtained from Kenya National Bureau of

Statistics. Household Questionnaires, Interviews, water samples will be used.

Raw water samples was taken to University of Nairobi-Civil Engineering Department water

laboratories for analysis. The results was compared against the required standards.

In order to obtain the other objectives like the specifications for the raw water treatment

works and related components, it was important to design the Coagulation, Flocculation,

Sedimentation tanks, Filtration, back wash and disinfection storage tanks based on the water

demand of the area in year’s projection plus the criteria set standards in Kenya. There was

equally need to use AutoCAD design drawings for the design capacity for the project. It

involved use of AutoCAD software, Google earth, Google Maps and Laptop computer.

Different data were needed for the design of a raw water treatment system in Nyansiongo

area. Methods of data collection had to be established beforehand to ensure the process will

efficient. Once the data was collected it was analyzed to produce an outcome that satisfies the

objective of the report. The data collected include:

a) Population of the area.

b) Land use.

c) Topographical data.

d) Existing water supply.

e) Information on water consumption per capita in the area.

f) Water samples.

In order to obtain this data various data collection methods were used as shown below.

4.2 Data collection methods

Various methods were employed to collect data needed for the design of the system. Both

primary and secondary data were needed.These include:

a) Questionnaires.

b) Interviews.

29

c) Literature review.

d) Government agencies.

e) Direct observation.

f) Samples.

4.2.1 Questionnaires

Questionnaires were prepared to aid with the collection of data. The questionnaires were

given to the relevant parties. In order to obtain an overview of water use in the area, the

questionnaire was handed to the community for a brief description on how they use the water.

With regards to the existing water supply, it was necessary to involve Gusii Water and

Sewerage Company with the use of questionnaires to obtain information on their existing

system.

4.2.2 Interviews

In addition to questionnaires, face to face interviews were also conducted. The interviews

were done to collect data on the challenges facing the existing supply of water and the

sources available for people in the area. These interviews were carried out with the members

living in the project area.

Information on the proposed source was also be required. The current population of the town

and the change of boundaries in the area over the past ten years information were obtained

from an interview conducted with the technical manager at Nyansiongo Tea Factory having

been the active users of the water from the dam as well as the local chief of the area.

Information on the change of boundaries was necessary in order to estimate the population

growth rate in the area.

4.2.3 Government Agencies

In order to collect topographical data, a map from the Google Earth was obtained for the area.

This map had information on the roads, contours, rivers, all the natural and man-made

features which were necessary for the design of the system.

4.2.4 Direct Observation

Direct observation for information on settlement and land use was necessary because of the

rate at which the town is growing. This was especially needed for the land site location for

the treatment plant.

30

Some problems associated with water problems could also be observed firsthand hand. These

included polluted water sources and broken down borehole pumps.

4.2.5 Sample

Water samples were taken from a water intake point identified. The three samples were taken

at very different river water depth, for example, sample one at 0.2m; Sample two at 0.8m and

Sample three at 1.4m below water surface.

4.3 Data Analysis Methods

This involves qualitative and quantitative analysis. The data collected by use of various

instruments was first be edited to get the relevant information. The edited data was coded for

easy classification in order to facilitate tabulation. The tabulated data was then be analyzed

by calculating the design capacities of the raw water treatment tank. Presentation of data was

to be in form of a report, calculations as well as AutoCAD drawings. Descriptive data was

provided in form of explanatory notes.

31

CHAPTER FIVE

RESULTS AND ANALYSIS

5.1 Population Data

The computation of the present and the future population is based on the geometric increase

methodPn=P0 (1+r )n . Growth rates for the area have been derived from the census conducted

in the country every 10 years. However the population to be served is primarily the

Nyansiongo Town and the outskirts.

Household: households includes all commercial and private residential areas within

Nyansiongo Town.

Livestock: they include all the domestic animals that are reared by the residents in

Nyansiongo Town majorly cows, goats, sheep and poultry.

Learninginstitutions: there are three major institutions in Nyansiongo Town, they include

primary schools such as Gesibei Primary School, Menyenya Primary School, high schools

including Menyenya high school as well as tertiary education institutions e.g. Borabu

Computer College.

Industries: The one major industry in Nyansiongo is the Nyansiongo Tea Factory. We also

have banking industry such as the Borabu Sacco and hotels e.g Borabu Inn

CommercialBuildings: they include the shops and supermarkets located within the town

center as well as the bars and cafés

NB: The growth rate of the Nyansiongo Town is assumed to be 1.83% (Nyamira-County,

2015) and the growth is projected linearly i.e. an increase in the household population leads

to an increase in the livestock at the same magnitude and that equally leads to an increase in

the number of students in schools by the same magnitude.

My area of projection is about 20% of the Nyansiongo Ward.

PARAMETER PER TOTAL +20%

32

POPULATION

CAPITA

DEMAND

WATER

DEMAND

ALLOWANCE

1999 2009 2019 2029

HOUSEHOLD 1700 3241 3886 4658 60 279480 335376

LIVESTOCK 400 900 1079 1293 50 64650 77580

COMMERCIAL

BUILDINGS

10 50 56 63 100 6300 7560

LEARNING

INSTITUTIONS

900 1500 1798 2155 25 53875 64650

INDUSTRIES 50 80 96 115 500 11500 13800

TOTAL 498966l/d

Figure 6: population in the Nyansiongo Area

498966l/d=0.01m3/s

5.2 Field Investigation and Data Collection

5:2:1Raw Water Quality Sampling

Raw water samples were collected from three different points at the Mosiabano Dam. The

samples were taken for testing to the University of Nairobi, department of civil engineering

and public health in Nairobi, Kenya. The samples ha to be carried in cool boxes to ensure that

they were uncontaminated and also had to be taken to the lab in not more than 6 hours so that

the biological components of the sample quality could not be affected i.e. die.

5.2.2 Samples Testing

1. Sample 1

The outstanding factor from physiochemicalwater quality test is the high level concentration

of iron ions (Fe+). In the bacteriology examination of water, the E.Coli (44oc) was determined

as nil making the water safe for domestic use. In the bacteriology, also the coliform

organisms and the plate/colony/total viable was determined (37oc). Results are attached on

appendix V and VI.

33

PARAMETER RESULT RECOMMENDED REMARK

pH 6.5 6-9 Complied

Apparent color 15.0 15 Complied

True color 10.0 15 Complied

Conductivityµ/S/CM mg/l 300.0 2000 Complied

Turbidity F.T.U mg/l 2.0 5 Complied

Calcium hardness CaCo3 mg/l 78.0 250 Complied

Total Hardness CaCo3 mg/l 210.0 500 Complied

Total Alkalinity CaCo3 mg/l 190.0 500 Complied

Carbonate Alkalinity mg/l 0.0 Complied

Iron mg/l 0.8 0.3 Failed

Fluorides mg/l 0.0 1.5 Complied

Sulphates mg/l 0.0 400 Complied

Dissolved oxygen p.p.m 4.8 2min Complied

Nitrates mg/l 0.8 10 Complied

Nitrites mg/l 0 10 Complied

Chlorides mg/l 80 250 Complied

Total coliform/100ml - Complied

Total Feacal Coliform/100ml - Complied

Dissolved solids mg/l 300 Complied

Suspended solids mg/l 50 Complied

Total solids mg/l 350 1500 Complied

Figure 7: physiochemical analysis of Sample 1

MICROBIOLOGICAL ACTIVITY REQUIREMENT

PARAMETER RESULTS RECOMMENDED REMARK

Plate/colony/Total Viable at 370c 35 100 Complied

MPN of coliform organism 15 Absent

MPN of Ecoli Nil Absent Complied

Figure 8: Bacteriology analysis of sample 1

34

2. Sample 2

In the physiochemical analysis, outstanding factor from water quality test is the high level of

iron ions Fe+. In the bacteriology examination of water, the E.coli (44oc) was determined as

nil making the water safe for domestic use. In the bacteriology, also the coliform organisms

and the plate/colony/total viable was determined (37oc). Results are attached on appendix VII

and VIII.


pH 6.63 6-9 Complied












Dissolved oxygen p.p.m 4.5 2 min Complied









Figure 9: Physiochemical analysis of sample II

35




MPN of coliform organism 18 Absent


Figure 10: Bacteriology analysis of sample II

3. Sample 3

In the physiochemical analysis, outstanding factor from water quality test is the high level of

iron ions Fe+. In the bacteriology examination of water, the E.coli (44oc) was determined as

nil making the water safe for domestic use. In the bacteriology, also the coliform organisms

and the plate/colony/total viable was determined (37oc). Results are attached on appendix IX

and X.


pH 6.64 6-9 Complied












Dissolved oxygen p.p.m 4.0 2 min Complied







36



Figure 11: Physiochemical analysis of Sample III




MPN of coliform organism 10 50


Figure 12: Bacteriology analysis of Sample III

5.3 Design of water Supply Features

The water intake from the dam is designed for the ultimate demand of supplying the residents

of Nyansiongo Ward water at the rate of 0.01m3/s as per 2029 in regard to the Kenyas Vision

2030.

5.3.1 Main pipe:

Volume flow, Q = 498.966m3/day =0.01m3/s

Elevation at the raw water intake, H1= 1575

Elevation at the treatment water works siteH2=1550

Change in elevation= ∆H= H1-H2 =1575-1550= 25

Distance between the intake and the works, (total length of the pipe), L=300

Pipe roughness coefficient=150 from the Hazel Williams Chart

Using Hazen-Williams equation (majorly used in determination of friction losses) to obtain

pipe diameter, D

∆ H=10.7 L ×Q1.852

C1.852× D 4.87 =

D=0.125m/125mm

Q=VA; A=π r2 = (3.142*1252)/4 = 0.01m2

Q=VA: V=1m/s

37

Determination of head loss due to friction in the pipes in the pipes:

Reynolds number:

Re=velocity∗diameter

viscocity

Re=0.01∗0.125

10−6

Re=1.25*105 therefore flow istabular

The value of coefficient of fluid friction was determined from the value of Relative

roughness, and the Reynolds number, Re from the moody diagram:

Re=1.25*105

¥=4.0*10-3

Coefficient of fluid friction=3.5*10-2

The head loss can be verified by using Darcy Weisbach equation:H f =fLV 2

D× 2g

Where:

Hf = head loss (m)

f = friction factor

L = length of pipe work (m) 700

d = inner diameter of pipe work (m)

v = velocity of fluid (m/s)

g = acceleration due to gravity (m/s²)

H f =3.5∗10−2∗700∗12

0.125× 2∗9.81= 10m

Since Hf2<∆H), Adopt the Head of 25m

5.3.2 Flocculation

Design flow = 498.966m3/day=0.01m3/s

38

Design retention time = 25 minutes

Using 3 compartments in series with values of G=50s-1, 30s-1 and 10s-1 in the first, second and

third compartments respectively:

Average G =50+30+10

3=30 s−1

GT value = 30s-1 × 45 × 60s = 81000 (since GT value is between 50,000- 100,000 the

detention time is considered satisfactory).

Basin volume, V = Flow, Q × detention time =468.966

24 ×3600×30 ×60=18 m3 taking width of

entire basin as 4m,

Top area = 18 ⁄ 4= 4.5m2

Assume compartments of square profile and let L represent the compartment width and

depth:

3L × L = 18m2

L = 2.1m

Width=2.1m

Total length of the basin = 3L = 3 × 2.1m = 6.3m

Total volume of the basin, V = ﴾6.3 × 2.1 × 15 ﴿ m3 = 198.45m3

Flocculation will be achieved by use of sinuous baffled channels which does not involve

mechanical moving parts. In this case the required mixing intensity is provided by the energy

dissipated due to the losses at the 180o bends of the baffles. The head loss over the total

channel will range from 0.3 – 1.0m. The loss of head is computed as 2-3.5 times the velocity

head for each 180o bend (half cycle turn) for round the end type.

The floor of the flocculator unit will have a 3.5% slope towards the outlet in order to maintain

a constant water depth.

5.3.3 Sedimentation Tank

Detention period: for plain sedimentation: 3 to 4 h, and for coagulated sedimentation: 2 to

2.5h.

39

Velocity of flow: Not greater than 30 cm/min (horizontal flow)/0.005m/s.

Tank dimensions: L: B = 3 to 5:1. Generally L= 30 m (common) maximum 100 m. Breadth=

6 m to 10 m. Circular: Diameter not greater than 60 m. generally 20 to 40 m.

Depth 2.5 to 5.0 m (3 m).

Surface Overflow Rate: For plain sedimentation 12000 to 18000 L/d/m2 tank area; for

thoroughly flocculated water 24000 to 30000 L/d/m2 tank area.

Slopes: Rectangular 1% towards inlet and circular 8%.

NB: One sedimentation tank is enough for use because of the general quantity of water

desired. Select the rectangular model because long rectangular basins are hydraulically more

stable, and flow control for large volumes is easier with this configuration. Taking a length to

width ratio of 4 (lying within acceptable limits), and using a length of 30m (such that width is

7.5m). The height is taken as 4m as it lies within the acceptable limits of 2.5m to 5m.

Surface Loading Rate = Q

Area=2.23 m3/m2 day

Weir Overflow Rate =Q

wier Length= 16.63m³/m day

Retention time=volume

flow /day=1.9 hours

The detention time for sedimentation tanks ranges between 1.2 – 4 hours, thus the value

calculated above of 1.9 hours is acceptable. It should have a slope of about 1% towards the

inlet as per the required engineering design to maximum and effective settling.

Dimensions of sedimentation tanks: 30m × 7.5m ×4

40

5.3.3 Filtration Tank

Rapid Sand filters

Net filtered water = (498.966m³/24hrs) = 21m³/hr.

Backwashing=2%

Backwashing time: 30 min

Total filtered water = Q/Day= 21.23m3/ h

Time

Let the rate of filtration be 1m3 / h / m2 of bed.

Area of filter =Total Filtered water x 1

rate of filtration = 21,23m2

Provide one unit. L/B = 1.3; 1.3B2 = 21.23

B = 4.04m; L = 4.04 x 1.3 = 5.25 m

Area of filter: 4.04*5.25

Estimated depth of sand:

Q × d³ ×hL= Bi × 29323

Where: Q = filtration rate in m³/m²/hr.;

d = sand size in mm;

H = total head loss in metres;

L = depth of sand bed metres;

Bi = breakthrough index (its value ranges between 0.0004 to 0.006 depending on the

response to coagulation and the degree of pre-treatment in the filter)

41

Layer Depth Size

Topmost 15 2-6

Intermediate 15 6-12

intermediate 15 12-20

Bottom 15 20-50

NB: Thickness of the gravel bed is 45-60m

The exact depth of the gravel can be estimated by:

L=2.54*K*log d (gravel size in mm)

Depth of sand = 32cm.

Underdrainage system:

Total area of holes = 0.2 to 0.5% of bed area.

Assume 0.2% of bed area = 5

100 x 21.23 = 1.06m2

Area of lateral = 2 (Area of holes of lateral)

Area of manifold = 2 (Area of laterals)

So, area of manifold = 4 x area of holes =4.24m2.

Diameter of manifold= (4∗manifold area

π¿^1/2 = 2.32m

Assume c/c of lateral = 30 cm. Total numbers = 7.5/ 0.3 = 25 on either side.

Length of lateral = length

2−diameter

2 = 0.86m.

42

C.S. area of lateral = 2 x area of perforations per lateral. Take dia of holes = 13 mm

Number of holes=bed area

area of the holes = 80

Number of holes per lateral = 80/50=2

Area of perforations per lateral = 13 x p (1.3)2 /4 = 17.24 cm2

Spacing of holes = length of lateral/number of holes per lateral =0.43m.

C.S. area of lateral = 2 x area of perforations per lateral = 2 x 17.24 = 34.5 cm2.

\ Diameter of lateral = (4 x 34.5/p)1/2 = 6.63 cm

Check: Length of lateral < 60 d = 60 x 6.63 = 3.98 m. l = 2.545 m (Hence acceptable).

Rising washwater velocity in bed = 50 cm/min.

Washwater discharge per bed = (0.5/60) x 4.04 x 5.25 = 0.18 m3s-1.

Velocity of flow through lateral = 0.36 = 0.36 x 10 4 = 2.08 m/s (ok)

Total lateral area 50 x 34.5

Manifold velocity = 0.36 = 1.04 m/s < 2.25 m/s (ok)

0.345

Washwater gutter

Discharge of washwater per bed = 0.36 m3/s. Size of bed = 4.04*5.25m.

Assume 3 troughs lengthwise= 1.4m c/c.

Discharge of each trough = Q/3 = 0.18/3 = 0.06 m3/s.

Q =1.71 x b x h3/2

Assume b =0.3, h=24m≠25cm

43

= 25 + (free board) 5 cm = 30cm; slope 1 in 40

Clear water reservoir for backwashing

For 4 h filter capacity, Capacity of tank = 4 x 1000 x 4.04 x 5.25 x 2 = 170 m3

1000

Assume depth d = 5 m. Surface area = 170/5 = 34m2

L/B = 2; 2B2 = 345; B = 13 m & L = 26 m.

Dia of inlet pipe coming from two filter = 50 cm.

Velocity <0.6 m/s. Diameter of washwater pipe to overhead tank = 67.5 cm.

Air compressor unit = 1000 l of air/ min/ m2 bed area.

For 5 min, air required = 1000 x 5 x 7.5 x 5.77 x 2 = 4.32 m3 of air.

5.3.4 Retaining Tank

Using a chlorine dose of 2mg/l; (which conforms to the WHO water standards which requires

that 2-3mg/l of chlorine should be added in order to gain satisfactory disinfection and residual

concentration)

Approximate amount required in 1 day = ﴾498.966× 3× 10-3 ≈﴿ 1.5kg/day

Assuming amonth has 30.4 days, the amount of chlorine required per day is 45.6kg≠50kgs.

Balancing tank: Minimum retention time = 30min

Q=0.01m3/s

V=QT=18m3

5.3.5 Storage Tank Capacity

The required total storage capacity of a reservoir capacity is the summation of: balancing,

breakdown and fire reserve. The balancing reserve can be estimated from data of hourly

consumption of water for the town. Due to the unavailability of this data, the storage capacity

44

is assumed to be 1/8 of the total daily water demand i.e. the storage water tank will be able to

store 1/8 of the quantity of water processed at the treatment plant per day.

Volume of the tank = 498.966

8=62.37 m3

Assuming the tank is a circular tank with a total height of 5.4m {including a free board of

0.4m}

Total surface area of the tank = 62.37

5=12.5 m2

Area=π r2Then radius becomes 2m

45

CHAPTER 6

DISCUSSION

The objective of this project was to design a raw water treatment plant at Mosiabano Dam.

This was determined by finding the projective population of the area by 2029 (In line with

Kenya’s Vision 2030manifesto). The per capita demand of water for different livestock,

institutions, commercial shops, industries as well as household were determined using the

geometric increase.

The raw water tests were conducted at the University of Nairobi Civil Engineering

Department, the Laboratory for Public Health. Both the physiochemical properties and the

bacteriological properties were determined. The water was determined to be slightly acidic

probably due to the acidic loam soils in the region (though it was lying within the KEBS

recommended standards) as well as with high levels of iron ions also due to the iron in the

soils in the region. The bacteriological analysis was found to be lying within the

recommended standards. The ecoli was performed at 440c because that’s the temperature at

which the bacteria thrives and is responsible for diseases such as diarrhea. The Plate count

and the coliform experiments were performed at 370c. the excess iron can be removed from

the water through

The information extracted from the water demand was used to design the features for the dam

from the intake pipe, flocculation chamber, the sedimentation chamber, the filtration tank as

well as the chlorination and storage tanks.

46

CHAPTER 7

CONCLUSIONS AND RECOMMENDATIONS

7.1 Achievement of Objectives

Specific Objective 1: Obtained human population, livestock and number of institutions of the

area and other data which I used to obtain the water utilization demand of the area.

Specific Objective 2: The Water Quality Test performed at the University Public Health

Laboratory helped determine the raw water quality.

Specific Objective 3: With water utilization need of the area determined, the specifications

for the raw water treatment works and related components could easily be determined. By

sharing of walls between some tanks/basins and also allows for water conveyance by gravity

in turn contributes to reduced construction costs and minimizing the pumping costs

respectively thus reduced water cost to the contractor and end users.

7.2 Conclusions

This project design procedure for the raw water treatment plant gives a clear step by step

procedure on how to determine the components of the raw water plant using the demand in

the area. This was to ensure that the overall objective of the design was optimally realized.

Through the design project, the water demand of the area was established, the water quality

determined and the specifications of the raw water treatment plant determined.

7.3 Recommendations

1. An EIA be conducted before the projected is carried out to identify the Environmental

impact of the project.

2. Design of other civil works like: office/ laboratory building, grade 9 staff housing, guard

housing, motor control centres for power supply, sluice drying chambers be incorporated at

or near the proposed site in order to provide a wholesome water treatment plant and a

distribution system of the area.

3. A water distribution system should be designed for easy access for it is use by humans and

animals.

4. A sewerage system design for the area should be done. This would reduce the amount of

pollution that goes into the rivers in the area.

47

7.4 Challenges of Study

Lack of a coolbox to carry the water samples to the lab for testing that could end up affecting

the quality of the samples.

Lack of sufficient funds on time to do pre-visit and visits to various data and sample

collection thus times working behind schedule.

Impossibility of supplying the water totally via gravity due to the terrain in the region, the

area is hilly.

48

REFERENCES

AMCW, A. M. (2015). http://wsp.org/sites/wsp.org/files/publications/CSO-Kenya.pdf.

Brooks, V. A. (2015). Understanding Water Treatment Processes. Tech Directions.

https://www.google.com/search?

q=raw+water+treatment+plant&rlz=1C1CHBD_enKE770KE771&source=lnms&tb

m=isch&sa=X&ved=0ahUKEwiVsoOttavZAhXK1xQKHejlAkMQ_AUICigB&biw=1

366&bih=595#imgrc=KsXY5dEmJ2EFZM:. (n.d.).

Muya, F. S. (2005). Water Design Manual Kenya.

( 2015). Nyamira County Annual Development Plan 2014/2015. Nyamira County.

Nyamira-County. (2015). Nyamira County Annual Developmen plan 2015/2015. Nyamira:

County Government of Nyamira.

Ongwae, S. (2017, October 12). Nyamira Residents Give Nod to Sh5b Water Project.

Standard Media Group.

Vasna, A. G. (2015). https://www.google.com/search?

q=raw+water+treatment+plant&rlz=1C1CHBD_enKE770KE771&source=lnms&tb

m=isch&sa=X&ved=0ahUKEwiVsoOttavZAhXK1xQKHejlAkMQ_AUICigB&biw=1

366&bih=595#imgrc=KsXY5dEmJ2EFZM:.

WHO, W. H. (2016). Global Health Observatory Data. Use of Improved Sanitation Facilities.

49

APPENDIX 1

Operational Definition of Terms

Jabia: Unimproved traditional storage

Raw water: water in its natural state or untreated water; it consists water from the

ground, infiltration wells water, and water from lakes and rivers, generally, water from

unimproved sources.

SDGs: are a collection of 17 global goals set by the United Nations. The broad goals are

interrelated though each has its own targets to achieve. They cover a broad range of economic

and social concerns of its member states.

Kenya Vision 2030: is the national long-term development policy that aims to transform the

country into a newly industrializing, middle-income country providing a high quality of life

to all its citizens by 2030 in a clean and secure environment. The Vision comprises of three

key pillars: Economic; Social; and Political.

World Health Organization: a specialized agency of the United Nations that is concerned

with international public health and it’s a member of the United Nations Development Group.

i

APPENDIX 2

A Map of the Nyansiongo Area

ii

APPENDIX 3

Bill of Quantities

ITEM QUANTITY COST/UNIT TOTAL

PIPES (PVC) 1000 200 200,000

LABOUR 400 300 120,000

CEMENT 100 bags 800 80,000

BALLAST 5 Lorries 30,000 200,000

SAND 5 Lorries 30,000 200,000

WATER QUALITY

TESTS

20000 20,000

TOTAL 820,000

iii

APPENDIX 4

Sample I Raw water Test Results (Physiochemical analysis)

iv

APPENDIX 5

Sample I Raw water Test Results (Bacteriology analysis)

v

APPENDIX 6

Sample I Raw water Test Results (Physiochemical analysis)

vi

APPENDIX 7

Sample I Raw water Test Results (Bacteriology analysis)

vii

APPENDIX 8

Sample III Raw Water Test Sample Results (physiochemical analysis)

viii

APPENDIX 9

Sample III Raw Water Test Sample Results (Bacteriology analysis)

ix

APPENDIX 10

Budget and Workplan

Budget

ITEM COST( KSH)

Transport 3,000

Communication and Research 800

Printing and Binding 2,200

Data Collection 2,000

Miscellaneous 2,000

TOTAL 10,000

Work Plan

Project Concept Note

Project Proposal

Project Preparation

Data collection

Data Analysis and Design

Report Writing

Nov-17 Jan-18 Mar-18 Apr-18 Jun-18 Jul-18

Chart Title

xi

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