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QUALITY OF WATER SUPPLIED BY WATER VENDORS

ROBERT YVONNE F16/29574/2009

UNIVERSITY

OF

NAIROBI

Department of Civil and Construction Engineering

QUALITY OF WATER SUPPLIED BY WATER VENDORS IN ONGATA RONGAI

ROBERT YVONNE

F16/29574/2009

Supervisor: Mr. Joseph Gitonga

This project is submitted as a requirement for the award BSc in civil engineering; University of Nairobi.

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DEDICATION This project is dedicated to my beloved parents and my brother Carlos Kamitu for their moral and financial support. Thank you for struggling to educate me and constantly advising me on life matters, I would not have come this far. May the Almighty bless you.





ACKNOWLEDGEMENT I would like to start by thanking the Almighty God for giving me the wisdom, knowledge and favour while writing this project.

I also wish to express my sincere gratitude to my project supervisor and lecturer in the Department of Civil Engineering, Mr. Joseph Gitonga for his earnest, industrious supervision, counsel, encouragement and productive criticism which was of great essence in the completion of this project report.

I would like to unconditionally thank my parents as well as my entire family and all well-wishers for the words of encouragement they constantly offered to me through the entire project.

Special thanks go to my brother Carlos Kamitu for his invaluable help both financially and morally. Thank you Carlos for reading through my project bit by bit andpositively criticizing it and pushing me to be more creative and helping me think outside the box.

I am grateful to the Public Health Laboratory Staff (Kaunda, Joy and Wambui) for their devoted help and cooperation while undertaking the laboratory experiments by availing all the apparatus I needed and for the limitless advice offered by the technologists.

Lastly, I wish to thank my fellow students for being resourceful and for their constant encouragement.

THANK YOU.





ABSTRACT

The objective of this project was to assess the quality of drinking water supplied to consumers by

the different types of water vendors and to determine its suitability in terms of the degree of

wholesome of the water. The area of study and survey is known as Ongata Rongai which began

in the late 1950s and its main supply of water is from boreholes. The quality of water is

established on a defined basis, usually in terms of quality requirements for potable water. Water

supplied by water vendors were tested for typical parameters such as; chemical substances,

physical properties, toxic compounds and bacterial quality. The values obtained were compared

with the World Health Organization (WHO) drinking water standards.

Nine sampling stations were identified within the area and sampling was carried out in each of

the water vendors identified. Rigorous laboratory testing was carried out and of the different

parameters and found to lie within the following ranges; Total hardness 117- 169 mgCaCO3/l;

Turbidity 1.8- 2.0 FTU; Total alkalinity 193-225 mgCaC03/l; Iron 0.4 mg/l; Conductivity 323-

675 µs; Total dissolved solids 36-96 mg; Total suspended solids 0 mg/l; chlorides 80.5- 142.5

mg/l, pH 7.72- 8.28; colour 15 Hazens; Faucal coliform, count was zero and Dissolved Oxygen

7.0- 8.5 mg/l. in the above experiments conducted, only Iron was found to be in excess of

recommended Drinking Water Quality Standards for Kenya (1996)

In conclusion water supplied by water vendors in Rongai contained high amounts of iron and

therefore there is an urgent need for a concerted effort to deionize the water before it is sold to

consumers. It is recommended that routine testing should be done to constantly and regularly

monitor the quality of water that is supplied. In additional, in order to avoid contamination of

ground water, there should be safe and effective handling of both industrial and domestic liquid

and solid wastes.





Table of Contents DEDICATION ............................................................................................................................................ 2

ACKNOWLEDGEMENT ............................................................................................................................. 3

ABSTRACT ............................................................................................................................................... 4

1. CHAPTER ONE.................................................................................................................................. 7

1.0 INTRODUCTION ........................................................................................................................... 7

1.1 GENERAL .................................................................................................................................. 7

1.2 WATER QUANTITY REQUIREMENTS................................................................................................ 8

1.3 PROBLEM STATEMENT ................................................................................................................... 9

1.4 THE PURPOSE AND SCOPE OF STUDY ............................................................................................. 9

2. CHAPTER TWO ................................................................................................................................... 10

2.0 LITERATURE REVIEW ...................................................................................................................... 10

2.1 WATER VENDORS ................................................................................................................... 11

2.1.1 DEFINITION ................................................................................................................. 12

2.2 BACTERIA CONTAMINATION OF WATER SUPPLIED BY VENDORS. ........................................... 17

2.3 BIOLOGICAL CHARACTERISTICS OF WATER. .......................................................... 19

2.4 PHYSICAL CHARACTERISTICS OF WATER ................................................................................. 20

2.4.1 Colour ............................................................................................................................ 20

2.4.2 Taste and Odour ............................................................................................................. 21

2.4.3 Turbidity ......................................................................................................................... 24

2.4.4 Temperature .................................................................................................................. 25

2.5 CHEMICAL CHARACTERISTIC OF WATER ................................................................................. 26

2.5.1 pH .................................................................................................................................. 26

2.5.2 Alkalinity ........................................................................................................................ 27

2.5.3 Hardness of water. ......................................................................................................... 28

2.5.4 Nitrates in drinking water ............................................................................................... 30

2.5.5 Dissolved oxygen ............................................................................................................ 32

2.5.6 Ammonia in water .......................................................................................................... 33

3. CHAPTER THREE ................................................................................................................................ 36





3.0 METHODOLOGY ......................................................................................................................... 36

3.1 SAMPLING PROTOCOL ............................................................................................................ 36

3.2 The rationale behind the choice of the station was; ............................................................... 36

3.3 SAMPLING .............................................................................................................................. 36

3.4 OBJECTIVES OF LABORATORY TESTING. .................................................................................. 37

3.4 LABORATORY EXPERIMENTS .................................................................................................. 37

3.4.1 DISSOLVED OXYGEN ....................................................................................................... 37

3.4.2 IRON ............................................................................................................................... 38

3.4.3 HYDROGEN CONCENTRATION OR pH .............................................................................. 38

3.4.4 CHLORIDE (Cl-) ............................................................................................................... 39

3.4.5 COLOUR ......................................................................................................................... 39

3.4.6 ALKALINITY ..................................................................................................................... 40

3.4.7 TOTAL HARDNESS ........................................................................................................... 40

3.4.8 SOLIDS ............................................................................................................................ 41

3.4.9 COLIFORM COUNT .......................................................................................................... 42

3.5 CHLORINE RESIDUAL .......................................................................................................... 42

4. CHAPTER FOUR .............................................................................................................................. 43

4.0 RESULTS ................................................................................................................................. 43

4.0 DISCUSSION ....................................................................................................................... 43

5. CHAPTER FIVE ............................................................................................................................... 56

5.0 INFERENCE AND RECOMMENDATIONS ................................................................................... 56

5.1 INFERENCE ..................................................................................................................... 56

5.2.1 RECOMMENDATIONS ......................................................................................................... 57

5.3 REFERENCES ........................................................................................................................... 58





1. CHAPTER ONE

1.0 INTRODUCTION

“WATER IS LIFE.” This is a common phrase used by people all over the World, but what

most ignores is the fact that the same water can turn out to be deadly if it does not conform to the

set standards and regulations by the registered bodies in the water department. On average we

use 126 liters of water per capita a day to drink, prepare food, for personal hygiene and for house

chores.

The government guarantees that everyone in Kenya has access to sufficient and safe drinking

water at an affordable price. Hence the government sets quality requirements for the production

and supply of water.

1.1 GENERAL

Water is put to many and varied uses and the quality requirements for the different uses also vary

widely. The water standards and requirements in Kenya specify that; the quality of drinking

water remains good, there should be sufficient water in the future (supply certainty) and water

remains affordable. Before water can be put to use it is important to know its quality this is done

by checking for its physical, chemical and bacteriological properties. There are numerous

Kenyan Regulatory bodies that standardize the quality of water before it reaches the consumers

they include:

Water Services Regulatory Board (WASREB),

Water and Sanitation Program (WSP),

World Health 0rganization (WHO)

Other independent monitoring bodies are:

Ministry of Water and Irrigation (MW&I)

Kenya Bureau of Standards (KEBS)

Ministry of Health (MoH)

The National Environment Management Authority (NEMA) among others.





The Water Act 2002 under section 47 requires WASREB to determine the standards, for the

provision of water services to consumers and to monitor compliance with established standards

for the design, construction, operation and mainly facilities for water services. All these bodies

are entrusted with the role of ensuring that the water supplied is safe, adequate and most

importantly affordable to the consumers in general.

One of the primary goals of WHO and its member states is that “all people, whatever

their stage of development and their social and economic conditions, have the right to

access safe drinking water.”

The first WHO document dealing specifically with public drinking-water quality was

published in 1958 as International Standards for Drinking-Water. It was subsequently

revised in 1963 and in 1971 under the same title. In 1984–1985, the first edition of the

WHO Guidelines for Drinking-Water Quality (GDWQ) was published in three

volumes: Volume 1, Recommendations; Volume 2, Health criteria and other

supporting information; and Volume 3, Surveillance and control of community

supplies. Second editions of these volumes were published in 1993, 1996 and 1997,

respectively. Addenda to Volumes 1 and 2 of the second edition were published in 1998,

addressing selected chemicals. An addendum on microbiological aspects

reviewing selected microorganisms was published in 2002.

1.2 WATER QUANTITY REQUIREMENTS

The objectives for a water distribution system are to provide safe, potable water for domestic

use, adequate quantity of water at sufficient pressure for fire protection, and industrial water for

manufacturing. Control of water quality for any purpose usually involves treatment. The goal of

water treatment is therefore that of altering or upgrading quality to a level appropriate for the

intended use. Water treatment is accomplished by engineered systems and if the quality is to be

changed, ways have to be found to decide when the change has been carried out far enough in

interests of both economy and suitability of treated water. This involves several concepts;

standard or requirements, criteria and guidelines. Criteria are usually a quantification of

characteristics of water quality which can be tolerated, and standards are legally enforceable





while guidelines are not. The World Health Organization (WHO) has provided guidelines on the

quality of drinking water. These guidelines are constrained by the prevailing environmental,

socio- economic and cultural conditions.

1.3 PROBLEM STATEMENT

Due to the climate changes in Kenya and at times long periods of drought in the country, water

supply becomes inadequate thus leading to consumers becoming desperate for water. In such

instances middlemen take advantage of the situation and pose as water vendors. This is quiet

risky as this middlemen are only interested in making money out of the situation, hence

endangering the lives of innocent consumers.

In Rongai, many commercial enterprises have sunk boreholes to supplement the water

requirements. However, with the lack of proper disposal of waste, the reliability of the water for

consumption is at doubt because there is the possibility of sewage seeping into the borehole

water. Water scarcity in Rongai is a major challenge, the main suppliers of water is Oloolaiser

water and Sanitation Company, this company has become ineffective as it can’t provide for all of

the high growing population of Rongai. There is a municipal water system that provides water2

days a week and private borehole system that provide water a few hours a day. If residents don’t

have enough water storage, they must buy water from vendors.

The vendors get the water mostly from boreholes. The water from the boreholes is sold to them

directly without any prior treatment thus leading to water borne diseases and hence the need for

water quality survey.

1.4 THE PURPOSE AND SCOPE OF STUDY

The aim of this project is to assess the quality of drinking water supplied by water vendors to

Rongai residents and hence determine its suitability.

This objective is achieved through the study of the followings;

Improved hygiene practices and education to prevent cross contamination





Assessment of water quality in Rongai vendors

The methods used to achieve the required drinking water quality

To establish the causes of ground water pollution

To develop recommendations for improvement of water quality from the vendors.

Sampling of water in Rongai and analyzing it for quality parameters and comparing the

results to the set WHO standards.

2. CHAPTER TWO

2. LITERATURE REVIEW Water is essential for life. Most animals and plants contain more than 60 % water by volume.

More than 70 % of the Earth's surface is covered with about 1.36 billion cubic kilometers of

water / ice.





Undoubtedly, water quality has tended to take a back seat compared to water quantity in the

provision of water in our country in an environment of limited potable water resources. But

proper water quality management will obviate the need to spend huge resources to address

waterborne diseases which contribute the largest percentage of bed occupancy in our hospitals.

The NWQMS (National Water Quality Management Strategy) will be the bench mark not only

for the protection of our water resources from pollution but also for ensuring the water provided

to the consumer is safe thus not harmful to health.

2.1 WATERVENDORS

A water vendor in Kenya basically refers to private firms or persons who bring water closer to

the consumers. They are of great importance because they bridge the gap by ensuring high

coverage levels albeit at a lower quality. They also extend water access to areas where there is no

infrastructure and no system of delivery. Lastly they also act as middlemen by buying from water

provider and reselling to consumers. On the other side of the coin, their disadvantages are; they

provide poor quality of water and their prices are exaggerated compared to those of the water

providers.

Examples of water vendors in Rongai include:

Tap water vendors.

Water kiosks

Carts filled with jerry cans driven by domestic animals such as donkeys or cows.

Water tankers mostly painted in blue with writings such as “CLEAN WATER”.

People who carry jerry cans on their back and supply it to consumers.

Borehole water vendors.





2.1.1 DEFINITION Tap water vendors are private entrepreneurs relying on a single piped connection; they sell water

that comes from the tap which is mostly supplied by the authorized organizations such as

Oloolaiser water and Sanitation Company in Rongai, usually selling water from their dwellings

or from a separate legal connection in a strategic location within the community. These vendors

are unregulated and consist mainly of landlords supplying tenants, sometimes through a small

piped network.

Pipe connections of tap water in Rongai

Water kiosks are water vendors who are formally licensed providers and are distinguished by

their better infrastructure. Most of the water kiosks belong to a group of people (chama) who

come together and ask for financial help to up it up. The financial help can come from the

government’s Community Development Fund (CDF) or by non-governmental organizations

(NGO s).They rely on a formal connection to the utility’s (NCWSC) piped network





Water kiosk in Rongai

Push cart vendors are people who operate pushcarts that are driven by domestic animals; the

most common in Rongai being the donkey-pulled carts. These operators obtain water mostly

from boreholes, water kiosks or through an illegal connection to the piped network. They resell

water to end users in 20-litre jerry cans. It was determined that less than half of the providers

surveyed said that they were subject to regulation but when asked for verification they claimed

the licenses were left at home which was questionable.





Water tankers can be public or private and they supply water in bulk to end users who can afford

storage. These tankers obtain water from either from private boreholes or directly from the utility

company. They supply water to mobile vendors for resale, but also sell water directly to end

users. However before commencement of operation all tanker truck operators require a business

permit, issued by NCC for a fee.





Borehole water vendors refer to people who sell borehole water to the community; this is very

common in Rongai since utility company doesn’t supply water all through. Borehole

construction is expensive and involves sunk costs associated with digging and construction, as

well as the purchase of pumps and storage tanks. Some vendors are able to finance construction

through revolving fund schemes. Before construction can begin, an official authorization is

required. Concerns over water quality and quantity are decisive factors in the regulator’s

decisions to authorize borehole construction. But quality testing is carried out only at the time of

licensing, with no subsequent monitoring. This is very dangerous since with time a lot of

contamination can occur as will discuss later.

Water vendors have been on the limelight of Kenyan news all for the wrong reasons; a good example is an article in the standard Newspaper;

http://www.standardmedia.co.ke/id=1144027062&cid=159&articleID=1144027062


http://www.standardmedia.co.ke/id=1144027062&cid=159&articleID=1144027062




“Beware of the water tankers that supply clean drinking water in

your neighborhoods. Word is out some of the vendors are using the

same vehicles to offer sewage services. The Government, through its

Internal Security PS Francis Kimemia, gave the warning on Sunday

following the death of 11 people from suspected cholera outbreak in

Makadara and Mukuru kwa Njenga slum. Two people died in

Makadara from what health officials confirmed to be cholera. In

Mukuru slum, at least nine people died last week with 700 being

taken ill. Health officials said the patients experienced stomach

pains, diarrhea and vomiting. However, the officials hinted that tests

carried out in the expansive slum showed that the disease was a

combination of cholera and another unknown disease. Mr. Kimemia,

who led officials from the Office of the President in a tour of the

affected area, issued a directive for all suppliers in Nairobi to have

their water tested to ascertain whether they were fit for human use.

Face the law "There are so many licensed and unlicensed water

tankers operating in the city. Wananchi have no way of knowing

whether the water they carry is fit for domestic use. The Government

will randomly stop them and carry out tests and if the water is

contaminated they will face the law," said the PS. For slum dwellers,

Kimemia announced that the Government would provide them with

clean water until the cholera outbreak is over.”

This article not only represents the poor sanitation of water but also shows how unethical and

greedy water vendors are. Therefore, guidelines in handling of water by vendors should be

followed to the tiny bit and all vendors should be licensed so as to operate in Rongai.





2.2 BACTERIA CONTAMINATION OF WATER SUPPLIED BY VENDORS.

Rongai region has grown rapidly over the years and unfortunately, up to date Rongai doesn’t

have a centralized sewer system. This is quite alarming because most building owners have

opted to evade the sewerage exhauster tanks because they are expensive. According to a careful

research and questioning of the residents, one trip of discharge of the exhauster is approximately

ksh. 10000. Apparently, due to the high cost of the exhauster, the owners of the buildings opt to

construct a septic tank in the buildings compound and when it fills up, they use a pump to pump

it out into the underground in the middle of the night so as to evade the law authorities.

This uncouth behavior has very many disadvantages but the major one being that it can lead to

seepage into the borehole leading to borehole contamination. Water contamination in Ongata

Rongai is high due to:

Domestic liquid and solid waste into rivers,

High levels of fluoride in the water supplied by water vendors from boreholes,

Dumping of organic and inorganic matter from the market (soko mjinga) on the

drainages,

Women washing their clothes on the banks of mbagathi and Kandisi River.

Poor urban planning and congestion as most people prefer to live by the roadside (linear

settlement) among many others.

The contaminants present in Ongata Rongai are: bacteriological contaminants, Magnesium,

Fluorides, chlorides and calcium and others. Dissolved mineral constituents can be hazardous to

both animals and plants if present in large concentrations. Too much sodium in water may be

harmful to people who have heart problems. Boron is a mineral that is good to plants in small

amounts, but it is toxic to some plants in only slightly larger concentrations. Therefore, like any

water supply scheme, water supplied by water vendors must have been treated to meet the

drinking water standards before it gets to the consumers. Water contaminated with pathogenic

microorganisms is a major avenue for the spread of infectious diseases. Many diseases may be

transmitted via a faecal-oral route, occurring when human faecal matter is ingested through

drinking contaminated water. Water is an important medium for transmitting disease as





contamination with excreta can lead to ingestion of faecal matter. The likelihood of acquiring a

waterborne infection increases with the level of contamination by pathogenic microorganisms

However, the relationship is not necessarily a simple one and depends very much on factors such as infectious dose and host susceptibility. (WHO, 2004 b)

Bearing in mind that Rongai doesn’t have a centralized sewer system there is a high

possibility of water contamination through the seepage of sewer from the wastewater from

the houses. The process of contamination of water is as shown below;

Figure 8. Classical Waterborne Infection Cycle

(Tebbutt, T.H.Y., 1992)

The quality of water, though not the sole determinant does have a great influence on public

The quality basically describes the physical, chemical and biological characteristics of water. It

is a measure of the condition of water to determine where the water is safe for drinking or not.





2.3 BIOLOGICAL CHARACTERISTICS OF WATER. Biological characteristics of water are the measure of the amount of harmful organism /

pathogens in water. Pathogens are biological organisms in water and wastewater which are very

dangerous, as they transmit disease, are not native to aquatic systems and usually require an

animal host for growth and reproduction.

Pathogens are easily transported by water, becoming a temporary member of the aquatic

Community, many species of pathogens are able to survive in water and maintain their infectious

Capabilities for significant periods of time include species of bacteria, viruses, protozoa, and helminthes. Lists of contaminants include;

2.3.1 Microorganisms Bacteria, viruses, parasites and other microorganisms are common in untreated water and can be

quiet deadly since they cause serious diseases. Some of the common outbreaks which are

common include;

I. Coliform bacteria: they exist as a group that include many strains such as E. coli and are

ubiquitous in nature. However it’s important to note that not all of them are harmful

hence they may not cause sickness. Due to daily use of water containing these bacteria

it’s possible for the consumers to develop immunity but however when visitors use the

water, then they can suffer from gastrointestinal distress such as diarrhea. Coliform

bacteria are mostly found in soils or vegetation hence gets into water when it rains and is

washed away. The best way to get rid of them is through disinfection or filtration.

II. Giardia Lamblia: this is a waterborne disease; it’s a flagellated protozoa that are parasitic

in the intestines of humans and animals. Giardia causes giardiasis which is characterized

by diarrhea, abdominal cramps, and nausea and weight loss. It mostly enters the water

when fecal materials are swept by water into water bodies. Water containing giardia

should be treated using both filtration and chlorination.

III. Hepatitis A: it’s a virus that is released to the environment through fecal waste which is

then washed away into the river. The symptoms of a person having it is; anorexia,

inflamed liver, weakness, nausea and jaundice.





IV. Helminthes: These are parasitic worms that grow and multiply in sewerage and wet soil.

They enter the body by burrowing through the skin or by injection of the worm.

However helminthes are not water borne so their chances of infections are less.

2.4 PHYSICAL CHARACTERISTICS OF WATER

The physical characteristics refer to the things we see in water but at the same time it should be

noted that most of the physical properties of water are quite atypical. Water has several important

physical properties. They include;

2.4.1 Colour Several tests can be carried out to determine the colour of water by supplied by vendors such

as the Nessler cylinder. Scientists have proven that pure water has a light blue colour which

increases to a deeper blue as the thickness of the sample increases. This colour occurs due to

the colour spectrum that is, due to the selective absorption and scattering of light spectrum.

Impure water may however have different colours this is due to dissolved or suspended

impurities both organic compounds such as tannins and those of mineral origins such as iron

and chromium, (Haslam,1990). The level of discolouration is matched against a standard

Hazen disc and measured in degrees hazen.

It is important to note that the colour of water through naked eyes does not determine the

extent of its pollution or how unsafe it is for consumption. Colour in itself is not necessarily

harmful because some substances that discolour water such as tannins are harmless hence a

scientific test should be carried out to determine whether it’s safe for consumption by the

public.

Table 2.4.1.1 Colours.

COLOUR OF WATER INDICATION

Yellow Presence of iron and humid compounds





Green Possibility of copper leaching from

copper plumbing.

The likelihood of algae growth.

Black Presence of sulphur reducing bacteria

growth especially inside hot water

tanks.

Red Indicates presence of rust in iron

pipes.

Presence of airborne bacteria from

lakes.

Milky / creamish Presence of carbonates, CaCO3

Blue- green colour Caused by the green algae in water

2.4.1.2 Solution

If after a scientific test the water is found to be unsafe for consumption then the colour of the

water can be removed by coagulation with chemicals, by the use of carbon which is very

efficient but large amounts of it are required thus making it quite expensive and also through the

slow sand filters.

2.4.2 Taste and Odour

Taste and odour are related because it goes without saying that bad odour will definitely cause

bad taste. Taste is what you feel or the sensation that is produced when water gets into the

mouth; its perception begins straight when the water gets on the tongue thus producing electrical

impulses from which you can tell whether the taste is good or bad. Odour on the end refers to the

smell of the water that is, does it smell fresh or foul.

Taste and odour can make the water undesirable to drink which is referred to as a cosmetic

effect, it can also cause a cosmetic effect which does not damage the body but it’s still

undesirable or it can cause a technical effect that is, it can reduce the effectiveness of treatment

of other contaminants.





In Kenya it’s normal to have water with the test and smell of chlorine because this is the most

preferred way to disinfect water, that is, by the use of chlorine. However it has come to the

notice of most Kenyans that some of the water vendors have decided to take this, as an

opportunity to get untreated water and pour in any amount of chlorine not knowing that excess

chlorine can lead to huge implications on the consumers. Although chlorination is an important

step in destroying bacteria and other harmful organisms present in water, it’s important to note

that it should be used in the right quantities to save the lives of the consumers.

Water coming from the authorized suppliers of water is in most cases is assumed to be safe for

consumption even if there’s some of odour or weird test, however there is always a likelihood of

contamination due to the long distances that the water travels before getting to the consumers

hence it may pose a health concern or even make the consumers reluctant on using it.

Taste and odour are caused by;

decomposing organic matter,

contamination of the water by the pipes that are distributing it,

algae present in the water,

Chloride,

Manganese,

Foaming Agents, Iron,

Copper,

pH,

Sulphates,

zinc,

Totally Dissolved Solids among many others.

Table 2.4.2.1 Taste. Taste Maximum Contamination

Levels

The contaminants

1. salty test 250 mg/l Chloride





2. Metallic test

1.0 mg/l

Non corrosive

0.3 mg/l

Presence of copper.

Corroded

pipes/fixtures staining.

Inorganic chemicals

such as iron.

3. Bitter test 0.5 mg/l Foaming agents

4. Bitter metallic test 0.005 mg/l

6.5- 8.5

Manganese

pH

Table 2.4.2.2 Odour. Odour Contaminants

1. oily smell

presence of petroleum products such as

oil or gasoline

Nuisance bacteria

2. Smell of Rotten egg Presence of hydrogen sulphide or

sulphates.

Sulphate reducing bacterial in soft

water reactions in electrical water

heaters.

3. Phenolic smell Industrial contamination.

Gasoline contamination.

4. Chemical smell Organic chemicals.

industrial

5. Smell of methane gas Organic decomposition.

Presence of gas in aquifer.





2.4.2.3 Solution

Despite this problem, there is no universal test or treatment for bad taste and odour problems, but

you can often find targeted ways to determine the causes and find solutions. Some tastes and

odors, especially those due to organic substances, can be removed from water by passing it

through an activated carbon filter. Other tastes and odors may respond to oxidizing agents, such

as ozone, hydrogen peroxide, and potassium permanganate.

Other treatments used to treat odour and taste include; softening, chlorination, coagulation and

distillation. However it should be noted that the type of pretreatment would depend on the

concentration and type of contamination and associated water quality, (Tebbutt, 1983)

2.4.3 Turbidity

Turbidity in water refers to how clear is the water or the degree of cloudiness or opaqueness of

the water. Turbidity is mainly caused by colloidal solids or finely divided suspended materials in

the water such as clay, silt, finely divided inorganic and organic matter, algae, plankton and other

microscopic organisms.

The degree of turbidity is measured by collecting samples of the water in question then shining

light through the sample. This measure is reported in nephelometric` turbidity units (NTU).

Colloidal particles generally have a vast surface area which is electrically charged with negative

charges hence it requires positive charges in order to neutralize it. Water from vendors who don’t

buy their water from authorized agents tends to have high turbidity levels because the water most

likely has been gotten from the rivers or streams.

In Kenya during periods of low base flow many rivers have a clear green colour which is an

indication of low turbidity level which is usually less than 10 NTU. On the other hand, during

rainy seasons the turbidity levels raise due to particles from the surroundings that are washed

into the river making the water muddy and brown in colour. Due to the heavy downpour and

high velocities of water cause turbulent flows which stir up the river beds thus increasing the

turbidity levels.





However it should be noted that clear water supplied by water vendors might not mean that it’s

safe for human consumption as it may possess acids, toxic metals and high levels of pH among

others.

2.4.3.1 Solution Turbidity can primarily be removed through filtration which refers to the removal of particles

and some contaminants through a porous medium. This filtration is basically divided into simple

and advance. They include:

Fiber, cloth or membrane filters

Slow sand and Bio sand filter

Granular media filters

Settling or plain sedimentation

2.4.4 Temperature Temperature refers to the warmness or the coldness of water. Water temperature affects most of

the physical properties of water such as;

The thermal capacity,

Density of water

Viscosity of water

Surface tension of water

Specific conductivity among others.

The above chemical and biological properties increase with increase in temperature.

Scientists have proven that reaction rates double up for an increase in temperature of 100C.

The temperature of water in streams and rivers varies from 0 t0 350C worldwide.





2.5 CHEMICAL CHARACTERISTIC OF WATER

2.5.1 pH pH is a measure of the alkalinity or acidity of water. pH value is measured through a pH chart

that ranges from 0 – 14.pH measures the concentration of hydrogen ions present in water. pH of

less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base and pH 7 represents a

neutral solution. pH is actually a measure of the relative amount of free hydrogen and hydroxyl

ions in the water. Water that has more free hydrogen ions is acidic, whereas water that has more

free hydroxyl ions is basic. Since pH can be affected by chemicals in the water, pH is an

important indicator of water that is changing chemically.

Water is ionized weakly as shown below;

H2O = H+ + OH-

For equilibrium approximately 10-7 molecular concentration of [H+] and [OH-] are present. [H2O]

may be taken as a unit;

[H+][OH-] = K= 1.0 X 10-14 mole/l at 250 C

[H2O]

pH can also be represented in a logarithmic equation which is;

pH = -log 10 [H+] = log 10 1/[H+]

pH is of great importance in water treatment as it determines the amount that can be dissolved in

water and the biological availability of chemical constituents in terms of nutrients (phosphorus,

nitrogen and carbon) and the harmful dissolved heavy metals (lead, copper and cadmium)which

make water unsafe for consumption.





2.5.1.1 pH chart.

2.5.2 Alkalinity

Alkalinity is a measure of the amount of natural water required to neutralize acid added to it.

Total alkalinity includes Hydroxides alkalinity [OH-], Bicarbonate alkalinity [HCO32-] and

carbonate alkalinity [CO32-]. Total alkalinity is the amount of acid required to reach a pH of

between 4.3- 4.8.

Total alkalinity = [HCO3-] + 2[C03

2-] + [OH-] – [H+]

As noticed above alkalinity is caused by bicarbonates carbonates and hydroxides ions in water,

which are in association with calcium, magnesium, sodium and potassium. In large quantities,





alkalinity imparts a bitter taste in water. The principle objection to alkaline water however is the

reactions that can occur between alkalinity and certain cations in water. The precipitation that

forms from this reaction leads to foul pipes and other water system appurtenances as seen in

Kumar, 2000.

Alkalinity in rivers comes from rocks, soils, salts, some agricultural activities and wastewater

from industries. However total alkalinity is measured by determining the amount of acid needed

to bring the water sample to a pH of 4.2. At this pH alkalinity has been neutralized by the acid

and the result is given as milligrams per liter of calcium (mg/l CaCO3).

2.5.2.1 Solution.

Total alkalinity can be determined by a double endpoint titration using a pH meter and a digital

titrator or burette whichever one prefers. This experiment can be carried out both in the field or

laboratory. If one prefers to carry out the experiment in the field then one is advised to use a

digital titrator because the burette is fragile and cumbersome to set up in the field. Titration

involves the process of adding small precise quantities of sulphuric acid also known as the

reagent to the sample until it reaches a certain pH which is called the end point. Sulphuric acid is

added in measured amount until the three main forms of alkalinity which are bicarbonates,

carbonates and hydroxides which are converted to carbonic acid. At pH 10, the hydroxide

present reacts to form water, while at pH 8.3 carbonates are converted to bicarbonates and finally

at pH 4.5 it is certain that all carbonates and bicarbonates are converted to carbonic acid. The

amount of acid used is measured and it corresponds to the total alkalinity of the water sample

tested.

2.5.3 Hardness of water.

Pure water is tasteless, colorless and odorless and is referred to as a universal solvent. Hardness

is the property that makes water to form scum when in contact with soap and has high quality of

minerals. Water that has hardness requires more soap for it to produce foam or lather. Water is a

good solvent and thus it easily picks up impurities hence the hardness in water. When water is





combined with carbon dioxide it forms very weak carbonic acid, as water flows through soil and

rocks it dissolves very small amounts of minerals and holds them in solution.

Hardness in water is not harmful for human consumption but can be precipitated by heating

although it can produce damaging effects in boilers through depositing the material and reducing

the water storage and carriage capacity.

Calcium Ca2+ and magnesium Mg2+ are the common minerals that cause hardness in water. The

degree of hardness becomes greater as the calcium and magnesium content increases and is

related to the concentration of multivalent cations dissolved in the water.

2.5.3.1 Hardness table Concentration of CaCO3 Degree of hardness

0 – 75 mg / l Soft

75 – 150 mg / l Moderately hard

150 – 300 mg / l Hard

300 mg / l and more Very hard

2.5.3.2 Effects of water hardness

Hardness in water used for domestic purposes causes a huge problem. The amount of hardness

minerals in water affects the amount of soap and detergent necessary for cleaning. Soap used in

hard water combines with minerals to form scum.

2 C17 H35 C00- + Ca2+ (C17 H35 COO)2 Ca

Some synthetic detergents are less effective in hard water because the active ingredient is

partially inactivated by hardness, even though it stays dissolved. Bathing with soap using hard

water leaves a film of sticky soap curd on the skin, this film prevents germs and dirt from being

washed out. Soap curd interferes with the return of skin to its normalcy and causes a slightly acid

condition that may lead to irritation. Washing clothes with hard water leads to stiff and rough

clothes and also reduces the efficiency of complete dirt removal on the clothes.





Hard water leads to inefficient and costly operation of water- using appliance. This is because

hard water forms a scale of calcium and magnesium minerals that can contribute to the

inefficient operation or failure of water-using appliances. Due to this deposition pipes become

clogged with scale that reduces water flow and ultimately requires repair or replacement,

(Kumar, 2000)

2.5.3.3 Solution

Low level of hardness can be easily removed by boiling or evaporation. High degree of hardness

is removed by the addition of lime. This method has also the benefit that iron and manganese

contents are removed and suspended particles including micro- organism are also reduced.

CaCO3 + CO2 + H2O → Ca2+ + 2HCO3-

2.5.3.4 Effects of water hardness

Hardness in water used for domestic purposes causes a huge problem. The amount of hardness

minerals in water affects the amount of soap and detergent necessary for cleaning. Soap used in

hard water combines with minerals to form scum.

2 C17 H35 C00- + Ca2+ (C17 H35 COO)2 Ca

Some synthetic detergents are less effective in hard water because the active ingredient is

partially inactivated by hardness, even though it stays dissolved.

2.5.4 Nitrates in drinking water

Nitrate (NO3) is a naturally occurring form of nitrogen found in soil. Nitrogen is an essential

compound to the human body and also to the crops in order to sustain high yield. Almost all

inorganic nitrate salts are soluble in water thus making drinking water unsafe for consumption.

Nitrates form in the nitrogen cycle and may leach into groundwater. Nitrates are safe when taken

in low quantities but extremely dangerous when taken in high quantities. When consumers take





water containing high quantities of nitrates it causes a disease called methemoglobinemia which

is common in infants.

Nitrates are common in;

Animal feedlots,

N-fixation from atmosphere by legumes, bacteria and lightning,

Septic systems,

Waste water and sludge

Fertilizers and manure

When water containing high levels of nitrates is consumed, nitrite is absorbed in the blood and

haemoglobin converted to mathemoglobin which doesn’t carry blood efficiently thus resulting in

reduced oxygen quantity in vital tissues such as the brain. Intense mathemoglobinemia results to

brain damage or death. Animals should not drink water with more than 100 mg/l NO3 –N

(nitrate-nitrogen) as it’s harmful. The excessive use of manure in agriculture is a significant

source of nitrogen and phosphate in the environment. Discharges from factories and sewers, as

well as nitrogen from exhaust gases, also play a role. Dutch fertilization policy is aimed at

preventing excessive fertilization as much as possible. Since the introduction of the fertilization

policy, excessive fertilization is less common. Use of crop protection agents for agriculture

causes local and temporal effects in quality of water, because some frequently exceed the

maximum allowed limits.

2.5.4.1 Solution

It’s important to protect the water supply points to avoid contamination; high nitrate levels are

often associated with poorly constructed or improperly located wells. Wells should be located

uphill and at least 100 feet away from feedlots, septic system, barnyards and chemical storage

facilities and they should be sealed or cap abandoned to prevent contaminations.





Sources of water pollution should be managed to limit the loss of excess water and plant

nutrients and fertilizer and irrigation should be matched to precise crop uptake needs in order to

minimize groundwater contamination.

2.5.5 Dissolved oxygen

Dissolved oxygen in water is vital for underwater life as it’s what aquatic creatures use to

breathe. Its presence is essential to maintain the higher forms of biological life and the effect of a

waste discharge on a river is largely determined by the oxygen balance of the system. Dissolved

oxygen is measured in milligram per liter or as percent air saturation. 100% air saturation refers

to the amount of dissolved oxygen that would be in water if it were completely saturated with air.

Dissolved oxygen levels fluctuate seasonally and over a 24- hour period. It varies with water

temperature and altitude. Cold water holds more oxygen than warm water; water holds less

oxygen at higher altitudes. Clean waters are normally saturated with Dissolved Oxygen, but such

D.O can be rapidly removed by the oxygen demand of organic wastes. Water with oxygen tends

to have a pleasant taste.

2.5.5.1 Factors that affect dissolved oxygen

The nutrient pollution in water; the amount of nutrients in water also referred to as

eutrophication fuels the growth of algae. Due to the nitrogen cycle; oysters and other

filter feeders eat a portion of the excess algae. The leftover algae normally die and sink at

the bottom of rivers. In this process, bacteria consume oxygen until there is little or none

left in the bed of rivers hence reducing the amount of oxygen present.

High levels of temperature; Temperature reduces the amount of oxygen that can dissolve

in water. Most rivers contain high oxygen content in cold seasons than in dry / hot

seasons.

Flow of water; the flow of water greatly influences the amount of oxygen in water, if the

flow is turbulent then the amount of oxygen is high because this flow allows for complete

mixing of oxygen with water unlike if it’s a still flow. Water from fresh rivers weighs

less than that from salty oceans due to this reason water from rivers floats on the ocean

waters. The boundary where the fresh water layer meets the saltier water layer is called





the pycnocline. The pycnocline acts as a physical barrier that prevents the two layers

from mixing together. On hot seasons when bacteria are active consuming algae, the

pynocline cuts off oxygen-deprived bottom waters from oxygen-rich surface waters. Thus

creating a large area of low or no oxygen at the bottom of the bay.

2.5.5.2 Solution

The amount of dissolved water can be increased or maintained by;

o Encouraging the growth of bay grasses and algae because they release oxygen during

photosynthesis.

o Allowing water to flow into the bay from streams, rivers and ocean. Since ocean water

contains more oxygen and river waters are fast –moving which helps oxygen from the air

to mix.

o Water fall aerators; it consists of steps of trays arranged in a structure 1.2 – 3m high

consisting of 4-6 steps or trays. The trays are at times perforated with small holes to

facilitate the oxygen absorption into the water. The water should flow at 0.015- 0.045

m2/m3/hr. for complete aeration.

2.5.6 Ammonia in water

Ammonia has a molecular formula which is NH3 and the ammonium cation NH4. Some of the

physical and chemical properties of water include;

Melting point -77.76 °C

Boiling point -33.43 °C

Water solubility 421 g/litre at 20 °C; 706 g/litre at 0 °C

Ammonia is used in fertilizer and animal feed production and in the manufacture of fibres,

plastics, explosives, paper, and rubber. It is used as a coolant, in metal processing, and as a

starting product for many nitrogen-containing compounds. Ammonia and ammonium salts

are used in cleansing agents and as food additives and ammonium chloride is used as a diuretic.

On dissolution in water, ammonia forms the ammonium cation; hydroxyl ions are formed at

the same time. The equilibrium constant of this reaction, is 1.78 × 10-5. The degree of





ionization depends on the temperature, the pH, and the concentration of dissolved salts.

Natural levels in groundwaters are usually below 0.2 mg of ammonia per litre. Higher natural

contents (up to 3 mg/litre) are found in strata rich in humic substances or iron or in forests.

Surface waters may contain up to 12 mg/litre. Ammonia may be present in drinking-water

as a result of disinfection with chloramines.

The presence of ammonia at higher than geogenic levels is an important indicator of faecal

pollution . Taste and odour problems as well as decreased disinfection efficiency are to be

expected if drinking-water containing more than 0.2 mg of ammonia per litre is chlorinated

as up to 68% of the chlorine may react with the ammonia and become unavailable for

disinfection . Cement mortar used for coating the insides of water pipes may release

considerable amounts of ammonia into drinking-water and compromise disinfection with

chlorine.

The presence of elevated ammonia levels in raw water may interfere with the operation of

manganese-removal filters because too much oxygen is consumed by nitrification, resulting in

mouldy, earthy-tasting water. The presence of the ammonium cation in raw water may

result in drinking-water containing nitrite as the result of catalytic action or the

accidental colonization of filters by ammonium-oxidizing bacteria.

2.5.2 Organic matter in water. Organic matter refers to substances that occur naturally, decay and decompose. Natural organic

material in water includes humic and non- humic fractions. Natural organic matter is classified

by solubility which is a measure of particle size. Particles under 0.45 micron are classified as

dissolved, while particles over 0.45 are classified as colloidal or particulate

Colloidal matter can be removed by filtering while the dissolved matter is monitored using UV

light absorbance as described in Standard Method 5910 B.

2.5.3 Pollution of ground water. Ground water as the name suggests is water found underneath the ground level. It mostly comes

from;

infiltration of rain water and

melting of snow





This water socks into soil and rock thus making an aquifer. Almost half of Kenyans water comes

from ground water and this water is collected and disinfected before being supplied to

consumers.

Ground water can have almost pure water hence it’s important for several tests to be carried out

before distributing the water. However it has been proven that the height of ground water or well

can determine the extent of the pollution. The deeper the well, the better the quality of water.

Ground water mostly has contaminants that are not involved with human activities or pollution

since it’s far below the ground surface.

As ground water moves throw the ground it comes into contact with rocks and soils that have

different minerals and salt that are depending on the quantity may be harmful for human

consumption such as;

Magnesium

Chlorides and

Calcium among others.

Other elements that are dissolved in some ground waters include;

Arsenic

Boron

Selenium and

Radon which is a gas formed by the natural breakdown of radioactive uranium in soil.

Human activities also lead to pollution of ground water such as;

Improper use of both artificial and natural fertilizers such as animal manure, herbicides,

pesticides and insecticides.

Poor urban planning especially the allocation of sewer lines and septic tanks. This is because

if poorly planned some of the sewer water may seep into the groundwater leading to

pollution.

Industrial activities; some industries discharge waste water which in most cases contains

chemical waste hence making the water acid and not safe for consumption.

Improper disposal or storage of wastes from households which at times finds its way to water

bodies hence polluting the water.





2.5.4 Disinfectants in water. Disinfectants are products that are used in water treatment in order to get rid of disease- causing

organisms such as pathogens. Disinfectants can be complicated to use because certain microbial

pathogens such as cryptosporidium are highly resistant to tradition disinfection.

To protect drinking water harmful organisms water suppliers add disinfectants to disinfect the

water. Water suppliers normally get a challenge when trying to determine how to control and

limit the risks from pathogens and disinfection byproducts.

3. CHAPTER THREE

3.0 METHODOLOGY

3.1 SAMPLING PROTOCOL

Sampling was carried out three times in Ongata Rongai. The stations involved were mainly the

water vendors. On the first two days, sampling began at 2:00 pm and continued throughout the

day until 4.00pm. On the third day sampling began at 8:00 am and continued up to 11:00pm.

3.2 The rationale behind the choice of the station was;

Its proximity and availability to the people living in the area

Easy accessibility of the sampling station

The distance between sampling stations should vary significantly so as to ensure the

water supplied by the vendors is not from the same supplier or borehole.

3.3 SAMPLING

Sampling was carried out in two different days and the samples were immediately taken to the

University of Nairobi Public Health Engineering Laboratories and the testing began immediately.

The samples were taken in three different sampling bottles in which two one- liter sampling





bottles provided in the laboratory was used for the chemical analysis and physical test while the

other carefully sterilized one was used for bacteriological examination in order to avoid any form

of contamination. The samples were refrigerated at a temperature of 40C while waiting testing.

Tests such as Dissolved oxygen and pH were taken immediately in the laboratory to avoid any

more sources of error taking account of variations due to transportation. It would have been more

appropriate to measure the Dissolved oxygen and pH on site but it wasn’t possible due to lack of

equipment and inadequate resources.

3.4 OBJECTIVES OF LABORATORY TESTING.

To check if the water is free from disease-causing organism

Free from toxic and physiologically harmful substances

To ensure the water is palatable

3.4 LABORATORY EXPERIMENTS

3.4.1 DISSOLVED OXYGEN APPARATUS

Dissolved oxygen bottles

Pipettes

Burette

Stands

REAGENTS

Manganoussulphate solution

Concentrated sulphuric acid

Starch indicator solution

Alkali-azide-iodide reagent

Standard sodium thiosulphate solution, 0.025N

PROCEDURE

The sample was collected in the dissolved oxygen bottles for at least a minute. The stopper was

then carefully replaced so that no air bubble was trapped in the bottle. The stopper was removed

and 2ml of Manganoussulphate solution and Alkali-azide-iodide reagent were added in quick





succession with the tip of the pipette well below the water level in the bottle and the stopper was

carefully replaced. The contents were then mixed several times and the precipitate left to settle

half way down the bottle and the process was repeated for the second time. 2 ml of concentrated

sulphuric acid was also added to the contents in the bottle and the contents were mixed until the

precipitate was dissolved. 203 ml was measured from the bottle and transferred to an arlenmeyer

flask. It was titrated against standard sodium thiosulphate solution till the colour changed to pale

yellow.1 ml of starch indicator was then added into the solution and titration continued until the

blue colour disappeared. The volume of the titrant used was recorded for analysis.

3.4.2 IRON APPARATUS

Separating funnels

Lovibond comparator

REAGENTS

Dilute hydrochloric acid

Potassium permanganate

Ammonium thonate solution

Amyl acetate alcoholic solution

Distilled water

PROCEDURE

5ml of the sample, 1ml of dilute hydrochloric acid and 2 drops of potassium permanganate

solution were added to a separating funnel and mixed. 5ml of ammonium thonate solution was

added followed with 10ml of amyl acetate alcoholic solution and the mixture shaken vigorously.

The solution was allowed to separate and the lower layer was discarded. The upper layer was

transferred to a comparator cell. The above procedure was repeated using distilled water instead

of the sample. The cells were placed in the comparator and then the colour produced matched

against the standard disc.

CALCULATION

mgFe/l = Disc reading x 200

3.4.3 HYDROGEN CONCENTRATION OR pH APPARATUS





100ml beaker

pH meter

SOLUTION

distilled water

PROCEDURE

75 ml of sample was placed in a 100ml beaker. The electrodes were raised carefully out of water

and rinsed with distilled water. Drops of water were wiped from the electrodes and then

immersed in the beaker containing the sample. The selector switch was turned again to

‘CHECK’ and the electrodes were carefully raised, rinsed with distilled water and replaced in a

beaker of distilled water.

3.4.4 CHLORIDE (Cl-) APPARATUS

Pipette

Burette

A stand

Conical flasks

REAGENTS

Silver nitrate

PROCEDURE

1ml of potassium chromate was added to 100ml of sample in a conical flask. The solution was

titrated with standard silver nitrate solution with constant stirring until a slight red precipitate

appeared. The volume of the titrant used was recorded.

MgCl/l= ml silver nitrate x 10

3.4.5 COLOUR APPARATUS

Nessler cylinder

PROCEDURE





The nessler cylinder was filled with the water sample and transferred to the light hand

compartment of lovibond. The colour of the sample was matched against distilled water. The

colour was read directly in degree hazens.

3.4.6 ALKALINITY APPARATUS

Conical flask

Pipette

Burette

Stand

PROCEDURE

100ml of the water sample was pipetted into a conical flask. A few drops of phenolphthalein

indicator were then added into the flask thus leading to a pink colour solution. Titration was done

against the solution until it became colourless. The volume was then recorded. A few drops of

methyl orange indicator was added to the same solution in the conical flask. The solution was

then titrated with N/50 sulphuric acid until the colour changed from yellow to orange. Titration

was done until the solution turned from yellow to orange-red. The volume of the acid used was

recorded.

3.4.7 TOTAL HARDNESS APPARATUS

Conical flask

Burette

Pipette

Stirring rod

REAGENTS

Ammonia buffer solution

Indicator tablet

N/50 EDTA solution

Stand

PROCEDURE





50 ml of the water sample was put in a conical flask. 1 ml of ammonia buffer solution was added

and one total hardness indicator tablet was crushed in the solution. The solution was then titrated

with standard EDTA solution till colour changed from wine red to blue.

For calcium hardness

50 ml of the sample of water was put into a conical flask. 1 ml of NaOH solution was added

which acted as a buffer solution. The burette was filled with EDTA solution. It was then titrated

with EDTA till the colour changed from pink to purple. The volume of EDTA used for titration

was then recorded.

Calculation

Total hardness as mg CaCO3 = ml EDTA X 20

Magnesium Hardness (as mg/l of CaCO3) = Total hardness (as mg/l of CaCO3) – Calcium

hardness (as mg/l of CaCO3)

3.4.8 SOLIDS APPARATUS

Filter paper

Forceps

Oven

Desiccator

Analytical balance

Vacuum pump

Funnel

3.4.8.1 PROCEDURE FOR TOTAL SUSPENDED SOLIDS A filter paper was dried in the oven at 1030 to 1050C for 1 hour. The filter paper was stored in the

desiccator. The filter paper was weighed immediately before use on an analytical balance. It was

mounted on to a suction pump. After shaking vigorously, a sample of 100ml was transferred to

the funnel by means of a 100ml volumetric cylinder. The filter paper was removed and dried in

the oven at 1030 to 1050C overnight to a constant weight. The filter paper and the contents were

weighed.

Calculation

TSS in mg/l = (weight before – weight after) x 1000





Ml of sample filtered

3.4.8.2 PROCEDURE FOR SETTLE ABLE SOLIDS The sample was shaken vigorously and fill rapidly one imhoff cone (1 litre). Allow one hour

settling time. Read the result in ml/l on the graduated marked on the imhoff cone.

PROCEDURE FOR TOTAL DISSOLVED SOLIDS

The petri dishes were labeled and their weights determined (W1). 100 ml of each sample was

measured and transferred into the petri dishes and the contents evaporated on a water bath. After

evaporation the dish and its content was oven dried at 1030C and weighed (W2)

CALCULATION

TDS= (W2—W1) X 1000

100

3.4.9 COLIFORM COUNT REAGENTS

Molten nutrient agar

APPARATUS

Petri dishes

Pipettes

Incubator

PROCEDURE

The petri dishes were labelled to correspond to the sampling stations. 1 ml of each sample was

pipetted and transferred to the petri dishes. Into each dish, molten nutrient agar held at 450 in a

water bath was poured to a depth of 3 mm. the sample was mixed gently with the agar and left to

set. After the agar had set, the dishes were inverted and transferred to the incubator. After 48

hours the colonies which had developed at 370were counted.

CALCULATION

Coliform count/ml = number of counts in 1 ml of sample

3.5 CHLORINE RESIDUAL APPARATUS

Lovibond comparator

Disc





Pipette

REAGENTS

Orthotolidine solution

Water sample

PROCEDURE

Two cells were filled with 10 ml of the water sample. 0.1 ml of acid orthotolidine was then

added to one cell and the contents were mixed. This cell was placed on the right hand

compartment of the lovibond comparator. The other blank cell was placed in the left hand

compartment. The residual chlorine concentration was then read matching the colour standards

of the disc with the colour in the cell.

4. CHAPTER FOUR

4.0 RESULTS

The results obtained from the three days of sampling from the public health laboratory were

repeated three times for each experiment so as to eliminate errors and ensure high degrees of

accuracy. The average of the three results was obtained from the following formulae;

AA = A1 + A2 +A3

3

Where

AA = Average value

A1 = value obtained from the first test

A2 = value obtained from second test

A3 = value obtained from third test

4.0 DISCUSSION The results of the different experiments done are discussed below.





4.1 TOTAL HARDNESS Total hardness is made up of carbonate which is the temporary hardness and permanent hardness

which consists of non-carbonate. Temporary hardness is easy to eliminate by boiling which leads

to formation of scales inside kettles or cooking pans. Permanent hardness is caused by the

presence of calcium and magnesium sulphates and cannot be removed by boiling.

The table that compares different levels of hardness is shown below;

4.1.1 Hardness comparison Range (mgCaCO3/l) Hardness level

0-50 Soft

50 - 100 Moderately soft

100 - 150 Slightly hard

150 - 200 Moderately hard

Over 200 Hard

Over 300 Very hard

4.1.2 Total hardness results table Samples (mm) S1 S2 S3 S4 S5 S6 S7 S8 S9

1ST Test Initial 0 0 8.4 0 0 0 0 0 0

Final 6.7 5.1 17.7 6.2 6.6 7.1 7.0 6.7 7.5

Reading 6.7 5.1 9.3 6.2 6.6 7.1 7.0 6.7 7.5

2nd Test Initial 6.7 5.1 17.7 6.2 6.6 7.1 7.0 6.7 7.5

Final 13.7 11.1 25.9 12.7 13.1 14.6 14.5 13.2 15.5

Reading 7.0 6.0 8.2 6.5 6.5 7.5 7.5 6.5 8.0

3rd Test Initial 13.7 11.1 0.0 12.7 13.1 14.6 14.5 13.2 15.5

Final 20.9 17.6 7.8 19.3 19.9 22.2 21.7 20.2 23.7

Reading 7.2 6.5 7.8 6.6 6.8 7.6 7.2 7.0 8.2

Avearage 6.97 5.9 8.4 6.4 6.6 7.4 7.2 6.7 7.9

Calculation=

(Average x 20)

mgCaCO3/l

139 117 169 129 133 148 145 135 158





The above results can be represented graphically as shown below;

4.1.3 Results graphical representation.

The values of hardness for the samples range from 117 mgCaCO3/l to 169 mgCaCO3/l. The

water is therefore safe for consumption because the Kenya Drinking Water Quality Standards

(KS 150-1996) which conform to WHO guidelines limits recommends a maximum value of 500

mgCaCO3/l. From table 4.1.1 it can be seen that the water is slightly hard.

4.2 TURBIDITY The turbidity results are as shown below;

Table 4.1 Results of turbidity samples 1 2 3 4 5 6 7 8 9

Results

(FTU)

2.0 1.9 2.0 2.0 2.0 2.0 1.9 2.0 1.8

The above results range from 1.8 FTU to 2.0 FTU. The turbidity is ok because it’s within the

stipulated standards which show that turbidity should be a maximum of5FTU. Turbidity more

0

20

40

60

80

100

120

140

160

180

1 2 3 4 5 6 7 8 9

TOTAL HARDNESS

S1 S2 S3 S4 S5 S6 S7 S9 mgCaCO3/l





than 5 FTU leads to high levels of disease-causing microorganisms such as viruses, parasites and

some bacteria which can later lead to nausea, diarrhea and headaches.

4.2.1 Graphical results.

4.3 TOTAL ALKALINITY Total alkalinity occurs due to the presence of bicarbonates, carbonates and hydroxide ions in the

water and may also occur due to the presence of calcium, magnesium, sodium and potassium.

When the value of temporary hardness is less than the total hardness then that’s alkalinity.

However in some waters, the total hardness is less than the alkalinity meaning it contains

sodium, bicarbonate alkalinity which does not affect the total hardness.

Table 4.3.1 Results of Total Alkalinity Samples (mm) S1 S2 S3 S4 S5 S6 S7 S8 S9

1ST Test Initial 0 0 0 0 0 0 0 0 0

Final 21.1 19.2 20.6 19.5 20.2 20.7 21.0 22.3 21.9

Reading 21.1 19.2 20.6 19.5 20.2 20.7 21.0 22.3 21.9

2nd Test Initial 21.1 19.2 20.6 19.5 20.2 20.7 21.0 22.3 21.9

Final 38.4 39.2 40.2 39.4 41.2 42.0 41.6 44.3 43.9

1.7

1.75

1.8

1.85

1.9

1.95

2

2.05

1 2 3 4 5 6 7 8 9

TURBIDITY

samples 1 2 3 4 5 6 7 8 9 Results (FTU)





Reading 17.3 20.0 19.6 19.9 21.0 21.3 20.6 22.0 22.0

3rd Test Initial 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Final 20.9 18.8 21.2 20.2 19.9 22.2 22.3 20.2 23.7

Reading 20.9 18.8 21.2 20.2 19.9 22.2 22.3 20.2 23.7

Average 19.8 19.3 20.5 19.9 20.4 21.4 21.3 21.5 22.5

Calculation=

(Average x 10)

mgCaCO3/l

198 193 205 199 204 214 213 215 225

The values obtained range from 193 mgCaCO3/l to 225 mgCaCO3/l. The Kenya Drinking Water

Quality Standards does not stipulate a specific figure for alkalinity hence the above results are

ok. High levels of sodium bicarbonate can lead to taste problems.

4.3.2 Graphical representation of the results.

4.4 IRON The results obtained are shown below:

4.4.1 Table of Iron results samples 1 2 3 4 5 6 7 8 9

170

180

190

200

210

220

230

1 2 3 4 5 6 7 8 9

TOTAL ALKALINITY

(Average x 10) mgCaCO3/l





reading 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002

Results

(mg/l)=reading

x200

0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

The iron content from all nine stations was found to be 0.4 as seen in the comparator. The Kenya

Drinking Water Standards is a maximum of 0.3 mg/l. the value obtained is higher than the

stipulated value thus it causes brown stain in pipes and laundry. Metal Remover System can be

used to remove the excess iron.

4.1.1 Graphical representation of Iron

It should be noted that iron is not harmful for consumption but it’s aesthetically undesirable.

Conversely, if present in large amounts it can convey a bitter test making the water foul-tasting.

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

1 2 3 4 5 6 7 8 9

IRON

Results (mg/l)=reading x200





Occurrence of iron in large amounts takes up oxygen when exposed to air consequently

precipitating causing brown stains on the pipes and even clothes washed with such water. This

further can cause odour in the water.

4.5 CONDUCTIVITY The results are as shown below;

4.5.1 Table of results of conductivity

samples 1 2 3 4 5 6 7 8 9

Results

(µS)

675 396 567 415 553 323 663 545 338

The results attained from the nine stations are represented above ranging from 323 µS to 675 µS.

This disparity is owing to the manifestation of dissolved salts of diverse concentrations which

conduct electricity.

4.5.2 Graphical representation of conductivity results

Conductivity is high during dry seasons and low during rainy seasons because of dilution effects

of water on the concentration of ions that are responsible for conductivity.

0

100

200

300

400

500

600

700

800

1 2 3 4 5 6 7 8 9

CONDUCTIVITY

Results (µS)





4.6 TOTAL DISSOLVED SOLIDS Total dissolved solids refer to those compounds that have liquefied in water and they are in ionic

form in the water. They can be either anions or cations. The results are as shown below;

4.6.1 Table of total dissolved solids.

sample 1 2 3 4 5 6 7 8 9

Weight of

crucible +

sample (g)

45.85 43.773 45.85 49.769 55.69 44.67 47.69 45.89 46.79

Weight of

crucible +

content

after (g)

45.946 43.811 45.905

49.814

55.749 44.706 47.776 45.968 46.839

Amount

(grams)

0.096 0.038 0.055 0.045 0.059 0.036 0.086 0.078 0.049

mg/l 96 38 55 45 59 36 86 78 49

The above results range from a maximum of 96 mg to a minimum of 36 mg. the variation is due

to the sources of water majority of which come from boreholes thus it depends on the rock

characteristics that are underground. According to the Drinking Water Standards the maximum

allowed is 1500 mg/l thus the results above are up to standards.





4.5.2 Graphical representation of total dissolved solids results

4.7 SUSPENDED SOLIDS In this experiment there were no suspended solids obtained in the nine stations. This is correct

according to the Kenya Drinking Water Standards which recommends that water used for

drinking should have zero suspended solids

4.8 CHLORIDES The results obtained were;

4.8.1 Table of results of chlorides Samples (mm) S1 S2 S3 S4 S5 S6 S7 S8 S9

1ST Test Initial 0 0 0 0 0 0 0 0 0

Final 13.5 9.1 8.7 9.5 7.9 11.0 10.7 8.2 9.8

Reading 13.5 9.1 8.7 9.5 7.9 11.0 10.7 8.2 9.8

2nd Test Initial 13.5 9.1 8.7 9.5 7.9 11.0 10.7 8.2 9.8

Final 28.5 19.1 16.6 18.1 16.1 20.7 21.2 17.9 19.8

Reading 15.0 10.0 7.9 8.6 8.2 9.7 10.5 9.7 10.0

Average 14.25 9.1 8.3 9.05 8.05 10.35 10.6 8.95 9.9

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9

TOTAL DISSOLVED SOLIDS

mg/l





Calculation=

(Average x 10)

mg/l

142.5 91 83 90.5 80.5 103.5 106 89.5 99

The values obtained ranged from 80.5 mg/l to 142.5 mg/l. according to the Kenya standards the

maximum value should be 250 mg/l, hence from the above results the water is safe for

consumption because the limit was not exceed. Effects of high levels chlorides are salty taste

which may lead to corrosion of metallic water pipes. High concentration can be identified by

blackish/ saline water.

4.8.2 Graphical representation of chlorides results

4.9 pH OR HYDROGEN ION CONCENTRATION The results from the nine stations are;

4.9.1 Table of results of pH samples 1 2 3 4 5 6 7 8 9

0

20

40

60

80

100

120

140

160

1 2 3 4 5 6 7 8 9

CHLORIDES

(Average x 10) mg/l





Results 7.86 8.25 7.65 7.92 8.28 7.72 8.13 8.15 8.24

The results range from 7.72 to 8.28 this is above the neutral point which is 7.0 from the pH chart

as discussed in the literature review. The variations in pH are due to presence of acidic and

alkalinity compounds of varying strengths. The Kenya standards state that pH should vary from

6.5 to 8.5 hence the above results are within the range and the water is safe for consumption. pH

below 6.5 is acidic and not safe for consumption while above 8.5 makes the water alkaline and

unsafe for consumption.

4.9.2 Graphical representation of pH values

4.10 COLOUR Habitually the colour of water should be clear. Nonetheless, colour in water is caused by inorganic dyes or coloured materials that are present in the water such as minerals for example iron and chromium. The results obtained from the nine stations are;

4.10.1 Table of results of colour samples 1 2 3 4 5 6 7 8 9

Results in

degree

Hazen

15 15 15 15 15 15 15 15 15

As observed in the above results the colour of water from all the nine stations was 15 degrees

Hazen. According to the Kenya Drinking Water Quality standards; water for drinking should be

7.27.47.67.8

88.28.4

1 2 3 4 5 6 7 8 9

pH

S1 S2 S3 S4 S5 S6 S7 S8 S9 Results





a maximum of 15 TCU (True Colour Units). The above results are precise. However, it’s

important to note that errors were likely to occur because the experiment was purely visual.

4.10.2 Graphical representation of colour results

4.11 FAECAL COLIFORM Faecal coliform was tested using the plate count experiment. In this experiment, the bacteria that

may be present in the sample was provided with suitable environment for growth and it was

assumed that each colony grew out from a single bacterium. Faecal coliforms are usually found

in the faeces of warm-blooded animals hence difficult to control.

In the above experiment the water sample had no faecal coliform which means that it does not

cause a serious health risk to those that use it for drinking. The presence of coliform is an

indication of bacterial contamination which can lead to bacterial infections and disease such as;

diarrhea, nausea, headaches and fatigue.

4.12 DISSOLVED OXYGEN The results obtained are as shown below;

4.12.1 Table of results of dissolved oxygen Samples (mm) S1 S2 S3 S4 S5 S6 S7 S8 S9

1ST Test Initial 0 23.3 0 21.3 0 0 0 0 0

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9

Results in mg/l

Results in mg/l





Final 7.5 30.5 6.8 29.1 7.7 6.5 8.2 7.9 7.7

Reading 7.5 7.2 6.8 7.8 7.7 6.5 8.2 7.9 7.7

2nd Test Initial 7.5 30.5 6.8 29.1 7.7 6.5 8.2 7.9 7.7

Final 15.6 37.4 14.1 36.7 15.6 13.3 16.8 16.1 15.9

Reading 8.1 6.9 7.3 7.6 7.9 6.8 8.6 8.2 8.2

3rd Test Initial 15.6 37.4 14.1 36.7 15.6 13.3 16.8 16.1 15.9

Final 23.3 44.8 21.3 43.7 23.6 20.3 25.2 24.6 24.4

Reading 7.7 7.4 7.2 7.0 8.0 7.0 8.4 8.5 8.5

Average 7.8 7.2 7.1 7.5 7.9 7.0 8.4 8.2 8.5

Results in mg/l 7.8 7.2 7.1 7.5 7.9 7.0 8.4 8.2 8.5

The maximum value obtained was 8.5 mg/l and the minimum value was 7 mg/l as shown in the above results. According to the Drinking Water Standards, there are no set standards to the amount of dissolved oxygen in water therefore the above results are up to standards.

4.12.2 Graphical representation of dissolved oxygen results

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9

DISSOLVED OXYGEN

Results in mg/l





Dissolved oxygen present in water makes it desirable for consumption and gives drinking water a

pleasant taste.

5. CHAPTER FIVE

5.0 INFERENCE AND RECOMMENDATIONS

5.1 INFERENCE In conclusion, although the water supplied to the consumers in Rongai was found to be of good

quality based on the results obtained from the experiments and the analysis from the nine

stations, the following conclusions were drawn;

a) Water from all the nine stations is fairly clear and has low turbidity levels without smell.

b) The amount of suspended solids was nil which means that water is not greatly polluted by

human activities such as improper solid waste disposal.

c) The coliform count obtained was zero which means that water supplied by water vendors

is free from bacterial contamination. This is possible because of proper use of pit latrine

in the area and also the good standards set up to ensure the water supplied conforms to

the drinking water standards.

d) In Rongai water is scarce because it’s a dry zone and hardly receives rainfall of

substantial amount thus only seasonal rivers exists. This is a huge problem because it

leads to lack of water for domestic use hence the increase of water vendors who are not

registered and they get there water from untrusted suppliers which can lead to diseases.

e) The scarcity of water in the region is a major problem which has led to many people

digging up boreholes. However, this is quite a challenge because people are digging up

boreholes blindly without going to the relevant authorities so as to avoid more expenses.

Lack of this information can lead to water borne diseases especially when people dig





boreholes near latrines. In addition there are rules that stipulate how many boreholes

should be in a specific place and how deep they should be therefore, if one does not

consider this while digging up a borehole then they may end up not getting water or they

may have to dig deeper which eventually ends up being quite expensive.

f) In the experiments conducted above all the other parameters were within the set standards

of Drinking Water (1996) other than iron which was slightly higher. Therefore it can be

concluded that water supplied by water vendors in Rongai is safe for consumption if the

iron levels are adjusted to conform to the WHO standards. Conversely, high amounts of

iron are not harmful for human consumption its only not good to the human eye that is,

aesthetically, therefore water supplied by water vendors in Rongai Town is safe for

consumption.

5.2.1 RECOMMENDATIONS

a) Chemical analysis should be carried out on all the water supplied by water vendors at

intervals of maybe thrice a year to ensure that the water supplied is up to the set standards

of WHO.

b) There should be a comprehensive study of the effects of the iron that is present and a

mitigation process should be considered to eliminate the excess iron so that the water can

be aesthetically clean for consumption.

c) The city council of Rongai should make sure that there is proper planning so as to ensure

that sewer lines don’t ran parallel to the water lines to avoid any form of contamination.

d) A detailed study of the biological quality of water should be carried out in all boreholes

in Rongai since they are the primary suppliers to water vendors so as to ascertain if there

is any contamination in the water due to human activities.

e) The town should regulate the number of boreholes supplying water to vendors and also

ensure that they comply with the set standards so as to ensure clean water and continuous

supply all year round.

f) Sensitize and educate communities on the policies, regulations and laws that concern

public health, ensuring that gender and cultural concerns and practices are addressed.

g) Develop a sustainable national programme on water and sanitation, suitable for Rongai

residents.





5.3 REFERENCES

1. Haslam, S.M, The biology of polluted waters; Liverpool University Press, UK 1960.

2. Kenya Drinking water Quality Standards (1996).

3. Kumar, S.G; Hydrology and water Resources Engineering, Khanna publishers.

4. World Health Organisation (1996) ; Guidelines for Drinking Water Quality , vol. 2,

Health Criteria and other supporting Information, World Health Organisation, Geneva.

5. World Health Organisation (1996) ; Guidelines for Drinking Water Quality, vol. 1

Reccomendations, World Health Organisation, Geneva.

6. World Health Organisation, (1976) ; Surveillance of Drinking Water Quality. World

Health Organisation, Geneva.

7. Tebbut, T.N.Y. (1979) ; Principals of water Quality Control, Pegamon Press, oxford

8. Gray, N.F. (1994; Drinking Water Quality, Problems and solution, John Wiley and Sons

Limited, Chichester, England.

9. NEMA website

10. American Public Health Association (ALPHA)



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