ampiire derrick intern report 2015 with alliance consultants ltd

KYAMBOGO UNIVERSITY

FACULTY OF ENGINEERING BACHELOR OF ENGINEERING IN CIVIL AND BUILDING ENGINEERING

INDUSTRIAL TRAINING REPORT

YEAR THREE 2014/2015

PROJECT: ALWI DRY CORRIDOR WATER SUPPLY SYSTEM

COMPANY: ALLIANCE CONSULTANTS LTD

TRAINEE: AMPIIRE DERRICK

12/U/158/ECD/GV

……………………………

COMPANY SUPERVISOR: Eng LUNGUBA GODFREY

……………………………………………

ALLIANCE CONSULTANTS LTD

UNIVERSITY SUPERVISOR: Dr. KYAKULA MICHAEL

……………………………………….

An Industrial Training Report submitted in partial fulfillment of the reward of Bachelor’s Degree in Engineering in Civil And Building Engineering at Kyambogo University.

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DECLARATION

I, AMPIIRE DERRICK declare that the content contained in this industrial training report is

entirely my original work and has never been submitted by someone else for the award of

Bachelors of Engineering in Civil and Building engineering of Kyambogo University. It

contains my findings during my industrial training.

Signature……………………… Date …………………………

AMPIIRE DERRICK

12/U/158/ECD/GV

Department of Civil and Building Engineering

Faculty of Engineering

Kyambogo University

+256 794 62 07 66 / +256 703 57 99 88

[email protected]

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PREFACE This report is an outcome of Industrial Training carried out in Nebbi district, Uganda with

Alliance Consultants Ltd. The report has been compilation of the practical work done over

the period in relation to the theoretical knowledge acquired in class about water supply and

water treatment systems.

The objectives of the industrial training include the following;

To enable the trainees get experience and be able to face the challenges of their field.

To equip students with the required knowledge of spear heading the construction

process.

Providing an understanding of the basis of valuation of properties and material costs

during construction.

Equipping students with knowledge and skills relating to property management,

valuation and other relevant fields.

To provide trainees with knowledge and skills to identify building defects and design

remedial measures and maintenance policies of buildings

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ACKNOWLEDGEMENT

First of all, I thank the Almighty God who gave me full life so I was able to work all the

industrial training period without any serious illnesses.

I also appreciate my family especially my mom for the time and support she has given to

bring me up to this academic level

I so much thank the lecturers, the university supervisor for the continued support towards

my academic life to be a success.

I also thank my mentor Arch Ssebunya Bashir for his continual guidance and instruction

throughout my academic life.

And finally I thank the Alliance Consultants Ltd team; the Managing Director Eng Joseph

Kabanga, Eng Kaddu Sebuyira Amos, Eng Lunguba Godfrey, Eng Kabali Ssenteza William,

Mr. Ssemujju Ivan who was in charge of my welfare, to mention but a few. They were

willing to train me and the attention they gave me was amazing. This encouraged me to set

my focus on this training and I surely learnt a lot as shown in this report.

Thank you so much.

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ABSTRACT I carried out my Industrial Training with Alliance Consultants Ltd in Nebbi district This report gives the details of the activities I was involved in due 15th June 2015 to 03rd

August 2015 with Alliance Consultants Ltd who were the Project’s Consultants.

The following are some of the activities that were accomplished during my training:

plumbing works like laying and joinery off different pipes, steel tank assembly, concrete

works like casting of rapid sand filter and clear water tank, tanking, carpentry works

specifically formwork assembly, surveying, ground water technologies and visits to other

sites..

I was wholly involved in the above works. However since the project was already

underway, about 60% of the project work had been done and by the time I left it was about

80%. So, some of the preliminary works and other major field works were not observed

such as site clearance and surveying works for setting out, tapping water from the intake

etc.

More is being detailed in this report as u read below

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TABLE OF CONTENTS DECLARATION ............................................................................................................................................... ii

PREFACE ....................................................................................................................................................... iii

ACKNOWLEDGEMENT .................................................................................................................................. iv

ABSTRACT ...................................................................................................................................................... v

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

LIST OF ACRONYMS AND ABBREVIATIONS ................................................................................................... x

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

ORGANISATION STRUCTURE OF ALLIANCE CONSULTANTS LTD ................................................................... 1

1.1 Description and Background ............................................................................................................... 1

1.2 The Organization Structure ................................................................................................................. 2

CHAPTER TWO: BACKGROUND AND PROJECT INFORMATION ..................................................................... 3

2.1 Introduction ........................................................................................................................................ 3

2.1.1 General ......................................................................................................................................... 3

2.1.2 Background .................................................................................................................................. 3

2.2 Major Components of the Works ....................................................................................................... 4

2.3 Districts and Community Liaison......................................................................................................... 6

2.4 Supervision Work ................................................................................................................................ 6

2.5 Site Handover and Commencement Date .......................................................................................... 6

CHAPTER THREE: CONTRACT DATA .............................................................................................................. 7

3.1 General ................................................................................................................................................ 7

3.2 The client ............................................................................................................................................. 8

3.2.1 Background .................................................................................................................................. 8

3.2.2 Vision ............................................................................................................................................ 8

3.2.3 Mission ......................................................................................................................................... 8

3.3 Contractors ......................................................................................................................................... 8

3.3.1 Vision Statement .......................................................................................................................... 9

3.3.2 Mission Statement ....................................................................................................................... 9

3.3.3 Quality Policy Statement .............................................................................................................. 9

3.4 Site layout and organization ............................................................................................................... 9

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3.4.1 Site general rules and time schedule ........................................................................................... 9

3.4.2 Health and Safety ....................................................................................................................... 10

3.4.3 Machinery and Equipment ......................................................................................................... 10

3.4.4 Materials’ supply and storage .................................................................................................... 12

3.4.5 Quality Control ........................................................................................................................... 12

3.5 Work progress, evaluation and communication ............................................................................... 13

3.5.1 How to Demand for water connection ...................................................................................... 13

CHAPTER FOUR: WATER INTAKE AND WATER STORAGE ........................................................................... 14

4.1 WATER INTAKE WORKS ..................................................................................................................... 14

4.1.1 Gabion boxes and mattresses .................................................................................................... 14

4.1.2 Fencing at the water Intake ....................................................................................................... 15

4.1.3 Concrete pedestals .................................................................................................................... 17

4.1.4 The intake chamber: .................................................................................................................. 18

4.2 WATER STORAGE .............................................................................................................................. 19

4.2.1 Assembly of a water reservoir tank ........................................................................................... 19

CHAPTER FIVE: PIPE WORK ......................................................................................................................... 21

5.1 Introduction ...................................................................................................................................... 21

5.2 Surveying for pipes ............................................................................................................................ 21

5.2.1 Levelling process of a Dumpy Level ........................................................................................... 21

5.2.2 Using and Levelling of the total station ..................................................................................... 23

Types of pipes ......................................................................................................................................... 26

5.3 High Density Polyethylene (HDPE) pipes .......................................................................................... 26

5.3.1 Advantages of HDPE pipes ......................................................................................................... 26

5.3.2 Joining of HDPE pipes ................................................................................................................. 27

5.4 STEEL PIPES ....................................................................................................................................... 29

5.4.1 Joinery by welding...................................................................................................................... 30

5.4.2 Joinery by Flange connections. .................................................................................................. 31

5.5 DUCTILE IRON PIPES .......................................................................................................................... 32

5.6 uPVC (Un-plasticised Polyvinyl Chloride) .......................................................................................... 33

5.6.1 Joinery of uPVC pipes ................................................................................................................. 33

5.6.2 Joinery of uPVC to steel pipes .................................................................................................... 35

5.7 Thrust blocks ..................................................................................................................................... 36

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5.7.1 Casting of Thrust Blocks ............................................................................................................. 36

CHAPTER SIX: FORMWORK AND CONCRETE ............................................................................................... 37

6.1 FORMWORK ASSEMBLY .................................................................................................................... 37

6.1.1 Formwork assembly of the clear water tank. ............................................................................ 38

6.1.2 Formwork assembly for rapid sand filter ................................................................................... 38

6.1.3 Formwork for dwarf walls .......................................................................................................... 38

6.2 CONCRETE PREPARATION AND CASTING.......................................................................................... 40

6.2.1 Concrete production .................................................................................................................. 40

6.2.2 Making spacer blocks ................................................................................................................. 41

6.2.3 Concrete production by Hand Mixing ........................................................................................ 41

6.2.4 OPERATING THE MIXER .............................................................................................................. 42

6.2.5 Casting process .......................................................................................................................... 43

6.3 Tests on concrete .............................................................................................................................. 44

6.3.1 SLUMP CONE TEST ..................................................................................................................... 44

6.3.2 COMPRESSIVE STRENGTH TEST OF CONCRETE .......................................................................... 46

6.3.3 Using the Compressive Strength test Machine .......................................................................... 47

CHAPTER SEVEN: WATER TREATMENT PLANT............................................................................................ 49

7.1 Raw water screening ......................................................................................................................... 49

7.2 Coagulation ....................................................................................................................................... 49

7.3 Flocculation ....................................................................................................................................... 50

7.4 Sedimentation/Clarification .............................................................................................................. 51

7.5 Filtration ............................................................................................................................................ 52

7.6 Final Chlorination .............................................................................................................................. 52

CHAPTER EIGHT: OTHER WORKS ................................................................................................................ 53

GROUND WATER TECHNOLOGIES (BOREHOLES) ........................................................................................ 53

8.1 Implementation ................................................................................................................................ 53

8.2 Ground water investigation .............................................................................................................. 54

8.2.1 Resistivity method...................................................................................................................... 54

8.3 Drilling. .............................................................................................................................................. 55

8.3.1 Rotary drilling ............................................................................................................................. 55

8.4 Development of the well. ................................................................................................................. 55

8.5 Determining the yield: ...................................................................................................................... 55

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8.6 Test pumping. ................................................................................................................................... 56

8.7 Installation. ....................................................................................................................................... 57

8.7.1 Procedure of installation ............................................................................................................ 57

8.8 Types of borehole wells .................................................................................................................... 58

8.9 Post construction/O&M phase. ........................................................................................................ 58

CHAPTER NINE: PROBLEMS, SOLUTIONS AND CONCLUSION ..................................................................... 59

9.1 PROBLEMS:........................................................................................................................................ 59

9.2 SOLUTIONS ........................................................................................................................................ 60

9.3 CONCLUSION ..................................................................................................................................... 60

APPENDIX 1 DRAWINGS .............................................................................................................................. 61

APPENDIX 2: PHOTOS ................................................................................................................................. 64

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LIST OF ACRONYMS AND ABBREVIATIONS

BPT Break Pressure Tank

DN Nominal Diameter

DWD Directorate of Water Development

ESIA Environmental and Social Impact Assessment

GI Galvanised Iron

GoU Government of Uganda

hr Hour

HC House connection

HDPE High Density Polyethylene

IPC Interim Payment Certificate

km Kilometre

kWh Kilowatt hour

l Litre

LC Local council

lcd Litres per capita per day

m Metre

m3 Cubic metre

m/s Metres per second

MWE Ministry of Water and Environment

No. Number

OD Outside diameter

PAP Project Affected Persons

PSP Public stand post

RGC Rural Growth Centre

uPVC un Plasticised Polyvinyl Chloride

UGx/UShs. Uganda Shilling

YT Yard Tap

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CHAPTER ONE

ORGANISATION STRUCTURE OF ALLIANCE

CONSULTANTS LTD

1.1 Description and Background Alliance Consultants Ltd is a limited liability engineering consultancy firm but

predominantly in Hydraulic Engineering.

It started 30th June 2003 as per registration date. It’s composed of a team of well trained

personnel able to take the standards of Uganda’s and in general Africa’s engineering to

extreme aptness.

Below are the details of its location and contact information;

Physical Address:

- Plot No: 398

- Floor no.: 2nd floor, The Ark House

- Street: Gayaza Road, Mulago

- Town: Kalerwe

- District: Kampala

- Country: Uganda

Telephone: +256 414 530160

P.O Box: 33975, Kampala

Email: [email protected]

On the next page is the organization structure of this company.

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1.2 The Organization Structure

Board of Directors

Technical Director

F.Ddumba

Head finance, Logistics &

Administration

Amos Sebuyira

Secretary

Annette M. Ndawula

Office Attendant

Sarah Nakabiri

Managing Director

Joseph K. Kabanga

Engineers / Technicians

P. Ssekadde

H,Mayombwe

K,Gyavira

A

Out Source Contract Staff

Administrative Staffs

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CHAPTER TWO: BACKGROUND AND PROJECT

INFORMATION

2.1 Introduction

2.1.1 General

The Government of Uganda is committed to a policy for the increased provision of

safe water supply and adequate sanitation to the whole population. The Rural Water

and Sanitation Investment Plan and Strategy aims at provision of safe and adequate

water and sanitation facilities for all by the year 2015.

Gravity flow scheme (GFS) development is among the technologies that have been

used for improved water supply in rural areas. The Ministry of Water and

Environment (MWE) through the Directorate of Water Development (DWD) is

supporting Districts in planning and development of large gravity flow schemes to

serve a larger number of beneficiaries across Local Government boundaries.

As part of this strategy, the Nyarwodho Gravity Flow Scheme is being developed to

supply population centres in the District of Nebbi.

2.1.2 Background

Nyarwodho Gravity Flow Scheme Project was conceived by Nebbi District in 2011 as

a contribution to the goal of increasing safe drinking water coverage in the water

stressed areas of Jonam County and Padyere County.

In 2012 MWE assumed responsibility for the development of the scheme

commencing with a Feasibility / Design Review, preparation of Tender Documents

and subsequent construction.

The Project covers 9 sub-counties in Nebbi District i.e Alwi, Pakwach & Panyango of

Jonam County and Kucwiny, Nebbi, Ndhew, Atego, Nyaravur and Parombo of

Padyere County. The population to be served is presented in the table below. Owing

to the size of the scheme, the Project will be implemented in phases.

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Nyarwodho GFS Projected Population to be served

County Sub County

Projected Populations in

Supply Area

2013 2033

Jonam Alwi 7,645 13,540

Pakwach 5,123 9,080

Panyango 6,861 12,150

County Total 19,628 34,770

Padyere Kucwiny 8,932 15,822

Nebbi, Ndeu & Atego 4,504 7,970

Nyaravur 6,400 8,520

Parombo 10,445 18,500

County Total 28,689 50,812

GFS Project Total 48,340 85,750

2.2 Major Components of the Works

The major components of the works are;

- Intake Works: Water abstraction from the River Nyarwodho, Erussi sub -

county, Nebbi District.

- Raw Water Main: 4.8km of OD250 uPVC pipeline with DN250 steel for

sections which run above ground.

- Water Treatment Plant: A 4,000m3/d water treatment plant located in Kei

village, Erussi sub - county, Nebbi District. The system components are as

follows:-

Coagulation and flocculation in baffled horizontal flow chamber

Sedimentation tank in rectangular flow chambers

Three rapid gravity filters

Treated water tank

Chemical house, office & laboratory with equipment

90m3 Backwash tank

Backwash pump house with solar powered system

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- Transmission Mains: 32.3km of OD280 – OD110 uPVC treated water mains

with 2No. 10m3 break pressure tanks.

- Storage Tanks: Pressed steel sectional ground level tanks of 31, 158 and

222m3 in Oweko, Nyaravur and Goti-Madi respectively.

- Distribution Mains: 40.2km of primary distribution pipelines in OD40 - OD90

HDPE and 15.2 Km of OD110 – OD 250 uPVC and 55.7km of secondary

distribution.

Transmission, Storage and Distribution Systems

Transmission

length (m)

Tanks supplied (m3) Independent Distribution

system (m)

Oweko 31 1,650

1,451 Nyaruvur 158 27,570

6,720 Goti-Madi 222 28,930

Totals 58,150

- Customer Connections: Water points will be installed on a demand-driven

approach where services will be installed at household level to serve

individuals or groups of individuals that have duly applied, confirmed as

meeting the sanitation guidelines, and paid a nominal fee. This will be

preceded by consumer awareness and sanitation campaign to be conducted

by a DWD Sociologists team.

- Office Block: 80m2 office blocks in Nyaravur and Alwi were equipped and

furnished under the Contract.

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2.3 Districts and Community Liaison

Crop compensation for PAP in the Sub – Counties of Ndhew, Atego and Nyaravur

was still under scrutiny by the Directorate of Water Development. Crop

compensation had been made to the Sub-Counties of Erussi, Nebbi Town Council

and Nebbi Sub – County.

The Mobilization team had been very vigilant in the field whenever they are called

upon to attend to community issues.

Reservoir sites of Oweko, Nyaravur and Goti-Madi were acquired (Agreements were

signed between the land owners and payments effected)

The Community Mobilization team at the District and Sub County continued to

sensitize and mobilize the Communities within the project area but most especially

those along the pipeline. The mobilisers move ahead of the Contractors route survey

team i.e. mobilisation precedes the excavation and eventual pipe laying.

The land for the Water Offices at Nyaravur and Alwi, was offered free of charge by

the sub counties.

2.4 Supervision Work Due to the afore mentioned events, Overall project (Singila & Wadelai RGCs and

Nyarwodho GFS) implementation period increased from the original twelve (12) months to

thirty three (33) months. Original Consultancy Contract was to expire on 28th July 2014.

The Consultant requested for the Contract to be extended to 31st January 2015 within the

original costs and thereafter the Client was advised to initiate the process of procuring

Construction Supervision Services to cover the period: February 2015 to end of

Construction: February 2016 and the twelve (12) months to cover the defects liability

period ending February 2017 in case it was not possible to extend the contract beyond 31st

January 2015.

2.5 Site Handover and Commencement Date The Commencement Date for construction Works was 3rd February 2014.

The construction site was handed over to the Contractor on 11th February 2014

The Ground Breaking ceremony was held on 20th May 2014 and it was presided over by the

Minister for Water & Environment, Hon. Prof. Ephraim Kamuntu and it was attended by

various dignitaries from the MWE, DWD, Nebbi District Local Government, and Lower Local

Governments to be traversed by benefit from the project and community member.

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CHAPTER THREE: CONTRACT DATA

3.1 General Project Title: Alwi Dry Corridor Water Supply Project (Construction of

Nyarwodho Gravity Flow Scheme Water Supply and Sanitation System Lot 1- Oweko,

Naravur & Alwi in Nebbi District)

Client: Ministry of Water and Environment.

Contract No: MWE/WRKS/12-13/01707

Project Funding: Government of Uganda (100%)

Supervising Engineer: ALLIANCE CONSULTANTS LTD in association with Infra-Consult Ltd.

Contractor: Vambeco Enterprises Ltd

Date of Site Hand-Over to Contractor: 11th February 2014

Commencement Date: 3rd February 2014

Contract Period: 24 Calendar months

Completion Date: 3rd February 2016

Contract Sum: UGX 25,717,827,680 (VAT exempt)

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3.2 The client The client was Ministry Of Water and Environment (MWE)

3.2.1 Background

Ministry of Water and Environment (MWE) is the ministry that has the responsibility for

Water & Environment management in terms of Policy Formulation, Water resources

Management, Resource Mobilization/Allocation and Regulation and Sanitation.

Sanitation is a shared responsibility between MWE, Ministry of Health, Ministry of

Education and Sports and the Respective Local Governments. MWE is fully responsible for

Sewerage

3.2.2 Vision

“Sound management and sustainable utilization of water and environment resources for

the betterment of the population of Uganda”

3.2.3 Mission

“To promote and ensure the rational and sustainable utilization, development and effective

management of water and environment resources for socio-economic development of the

country”

3.3 Contractors The contractors were Vambeco Enterprises Ltd which is mainly a construction

management company. It has quite a wonderful construction experience and outstanding

project history. They provided all the equipment and laborers required for the project.

They pride ourselves on being one of the few independently owned and managed firms

that performs all facets of construction and water projects, from installing the meter for

your home to distribution systems that feed villages. Their expertise includes all types of

construction.

With over 10 years of experience in the industry, they have a well-diversified and well

trained workforce that has the necessary knowledge and expertise to exceed industry

standards for construction while striving to provide customers with the best possible

service they can experience. The Vambeco philosophy is “Quality is Number One.”

Their eye is on the future and they are a growth oriented company looking for the right

individuals to help them continue to be successful.

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Their Affiliates

3.3.1 Vision Statement

To be the leading construction company especially in water-works in East Africa with an

expanded presence throughout Africa.

3.3.2 Mission Statement

To provide the highest quality construction services through constant upgrading of our

staff skills, creating equal opportunity, protecting the environment and discharging our

corporate social responsibility.

3.3.3 Quality Policy Statement

Vambeco Enterprises Limited is committed to employing quality employees, and shall

strive to satisfy our customer’s needs by executing the works to consistently high quality

standards at competitive prices and within the time-frame agreed to.

3.4 Site layout and organization This section includes the contractor information and site work

3.4.1 Site general rules and time schedule

Most of the workers were residents in Nebbi and the workers weren’t had a home set up

for them. They would leave their homes early enough so that by 7:00am they are at the

contractor’s office where they load materials on to the available trucks and by 8:00am they

set off. Usually there could be 3 sites running at the same time and in extreme cases 5-6

sites running co-currently on the same day. So sometimes there would be delays when cars

were mechanically down

Breakfast would be served immediately and materials to be used would be offloaded so

that by 9:00am, work kicks off.

Lunch was served from 1:00pm to 2:00pm

Standard time for work to close was 6:00pm.

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3.4.2 Health and Safety

Health and safety gear was available and supplied to the workers upon delivery of

every consignment. Standard equipment for each worker includes;

Helmet

Overall

Gum boots.

But since we came in the latter stages of the project, some of this safety gear wasn’t given

out as it was earlier. The contractors required the workers to come with their personal

safety items before they could be employed.

First Aid was given especially for minor cuts, nausea and headaches by medication being

provided by two nurses who moved with their first aid kits on site. In case of serious

injuries which couldn’t be treated on site, the casualty would be transported in the

company vehicle to hospital.

The water available at the sites was usually river water, borehole water was too saline

and the packed mineral water in shops was too expensive for the workers to buy. So clean

and fresh water was provided for drinking and cooking. It would be loaded on the vehicles

before leaving the contractor’s office.

Trusted cooks who were under the contractors did the cooking. One or two cooks,

depending on the number of workers, were taken to each active site. I happened to share

with the workers several meals and it was indeed nice food and at least I didn’t hear of any

ailments that arose due to eating the food. Bravo!

3.4.3 Machinery and Equipment

The heavier machinery include;

Concrete Mixers.

Pedestrian Roller

Pick-Up and Tippers

Wheel loaders with back actor

Block making machine

Generators

Welding equipment

I’ll talk about a few of the above equipment

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Generator

Generators were generally used as a power source for welding process. For the one shown

below, it was a single phase diesel generator of rated power 2.8kVA, rated frequency

50/60Hz and rated current 12.2A weighing 191kg. A welding torch/angle grinder was

connected to the cathode and another cable with an open end was connected to the anode

then to a metal piece so as to complete a circuit. It would then be switched on by pressing

the power button.

Angle Grinder

It was used to mainly cut pipes to required sizes especially steel pipes, for pipework at

treatment plant and transmission mains. Care should be taken while using it as it was

considered the most dangerous equipment on site. The angle grinders were manufactured

by Makita with voltage 220V and rated frequency 50/60Hz.

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3.4.4 Materials’ supply and storage

Materials were delivered on site by tippers.

Cement was stored at the contractor’s office. Types of cement used were Power Plus

cement, and multipurpose cement of the classes 42.5N and 22.5N respectively. And

deliveries made to site depending on the work to be done

Sand was from Akaba in Nyaravur sub county Nebbi

The 20mm aggregate was also obtained from a quarry plant in Nebbi.

All materials were safely kept in a store with a trusted store keeper to monitor the use or

else the site had to be hoarded for materials that are stored outdoor like aggregate, sand,

machines etc.

Pipes were supplied by GENTEX and Simba Multiple Industries Ltd both located in

Kampala, Uganda

Delivery of HDPE pipes on a truck Stacked uPVC pipes under a shade

3.4.5 Quality Control

Tests especially on concrete were done in Arua district at the Uganda National Roads’

Authority (UNRA) concrete laboratory. I was able to take part in some of the tests as

explained in chapter six section 6.3

Otherwise most of the other materials had to be accepted before they could be transported

to site.

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3.5 Work progress, evaluation and communication The work done was evaluated on a weekly basis. Meetings were usually between the client

representatives, the consultants, the contractors and local leaders especially on Thursdays

or Fridays.

An agenda of a typical site meeting is as follows

Opening prayer

Introduction and expectation

Briefing

Questions and Answers( Q & A)

Developing action plan

Conclusion

For example; a meeting was held on 24th July 2015 at Leosim Hotel, Nebbi district between

by the client, consultants, Nebbi district local government and sub county representatives

of Kucwiny and Ndhew.

The project was explained in detail to them and these are some issues which were brought

up

3.5.1 How to Demand for water connection

Express interest by visiting the sub county water office

Fill application form

Fulfill all hygiene requirements and other conditions

Pay for connection

Payment is according to;

Water Act Cap 152(1997)

National Water Policy (1999)

Tariff Policy (2008)

An action plan was developed as follows

Formation and submission of the names of the planning committee members

Community members picking and submitting forms to sub county

Display and assessment of applicants’ households

Displaying the final list of payments

Connections by consultants and contractor

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CHAPTER FOUR: WATER INTAKE AND WATER STORAGE This chapter is mainly about the water source and works involved at the water source and

also describes the assembly of the water reservoir tanks located in the various selected

areas.

4.1 WATER INTAKE WORKS Water abstraction from the River Nyarwodho, Erussi sub - county, Nebbi District.

Identification of Intake point

Gabion boxes and mattresses

Pipework

Concrete pedestals

Anchor blocks

Intake chamber

Chain link fence and Gate

4.1.1 Gabion boxes and mattresses

River Nyarwodho originates from the Democratic Republic of Congo highlands and the

point selected where the intake was located in the upstream of the river.

The base of the river at the specific point was also irregular because of the rocky formation

of the ground causing the turbulent flow in the movement of water and this couldn’t be

dealt with by crushing because of the high costs.

Therefore the speed of the water had to be reduced to make it possible to draw water from

the river by creating a small reservoir to keep the flow of water at a constant speed and to

acquire a constant amount during the dry and wet seasons of the year.

The laying of the gabion boxes and mattresses was done in the dry season of the year when

the water level of the river is low

The base of the river at the intake point was made regular by laying gabion

mattresses 2m x 1m x 0.3m, in galvanised steel wire fabric 50 x 50mm filled with

rock of size 50 – 150mm. This was also to stop water from penetrating through to

the other side of the gabion.

Gauge 1000 polythene sheet was placed between two layers of the gabion

mattresses to stop water from penetrating through.

Gabion boxes 2m x 1m x 0.5m, in galvanised steel fabric 50m x 50mm filled with

rock 150 – 300mm were lay to create the vertical barrier.

Gauge 1000 polythene sheet was placed between two layers of the gabion boxes to

stop water from penetrating through. The weight of the gabion mattresses and

boxes is strong enough to resist all the water pressure imposed by the water

approaching.

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Placing of Gabions at Intake Site

4.1.2 Fencing at the water Intake

Chain link fences were used at all the constructed sites at the water intake, water treatment

plant, water reservoir tank sites and site offices

Procedure of fencing

We first identified the area to be covered and then cleared away all obstructions to

ensure a reasonable level before pegging out the line of the chain link fence with

string.

We marked the position of the end straining concrete poles and dug holes for their

foundations. Holes were about 750mm deep and 500mm square

We then planted the end straining post and hand mixed concrete poured in the hole

so the bottom end of the post is embedded

We then fixed a line taut between the straining posts and set the intermediate

standards along this line at 2.5m intervals.

The concrete poles were plumbed with timber props until and the concrete sets and

hardens.

The intermediate standards were then also placed using the same procedure as the

end straining posts.

Then we unrolled the chain link fencing along the line of the fence pulling the mesh

as tight as possible as an assistant moves along. Then hold the fence to the line wire

using temporary tying wire or strings at intervals.

We then fastened the mesh to each straining post in turn and then continued to

complete the fence by connecting it by the tying wires.

Barbed wire was then attached at the top of the poles to limit access of intruders

jumping over the fence

16


NOTE:

At Oweko water reservoir tank, the ground was rocky so excavating up to 750mm was not

possible. The solution was a 500mm square pad un-reinforced concrete base was cast

around the pole and 250-300mm deep depending on the how deep the excavated hole

depth. This was by instruction of the foreman

Concrete ratio used was 1:2:4 (cement:sand:coarse aggregate) and was prepared by hand

mixing. Hand mixing is described in detail Chapter six (section 6.2.3).

Cutting tying wire with a pincher. Casting concrete for a plumbed concrete pole

17


4.1.3 Concrete pedestals

The ground was prepared for concrete and the pipes were supported by wooden

supports before the installation of the concrete pedestals.

Excavation was done at a stated depth according to directions from the consulting

engineer at positions with weak base were concrete pedestals were to be placed.

Formwork was then made using wood with fair finish in the interior for the bases of

the 1 x 1 x 0.5m and 0.8 x 0.8 x 0.4m and were supported and plumbed.

Formwork for the rest of the pedestal was then put up 0.5 x 0.3m with different

heights following the gradient the pipe is to follow to the intake chamber.

Steel reinforcement was made and fixed for the different pedestals High yield steel

square twisted bars Y12 at 150 c/c and Y16 at 150 c/c

The bases were made wet by pouring water to favour the joinery of concrete to the

bases of the existing ground.

Cement grout was then poured that is a mixer of water and cement to the base of the

existing ground.

Concrete blinding class C15 was cast 50mm thickness using multipurpose cement of

strength 32.5N mix ratio 1:2:3

Concrete for the base and the pedestal wall was then cast too of class C30 using

powerplus max cement of strength 42.5N mix ratio 1:2:3

Concrete pedestals supporting ductile iron pipe. Striking formwork off a concrete pedestal.

18


4.1.4 The intake chamber:

This structure is designed in a way that helps to remove silt that escapes through the

transmission line before reaching the treatment plant. It also blocks entry of bigger

undesirable particles from entering the pipes e.g. frogs, fish etc. This process is known as

screening.

The Screen at the intake.

19


4.2 WATER STORAGE Water was stored in three water reservoir tanks they were pressed steel sectional ground

level tanks of 31, 158 and 222m3 in Oweko, Nyaravur and Goti-Madi respectively.

4.2.1 Assembly of a water reservoir tank

I took part in assembly of the tank at Oweko. Below are the steps we took

The tank is assembled on reinforced concrete dwarf walls which are cast 1m above

finished ground level. The process of constructing these walls is explained in

Chapter Six.

1.22m square tank bottom plates were bolted to each other with rubber plugs

placed at lining between plates. Rubber plugs provide blockage to leaking along the

plate lining.

Plates should be clearly and accurately labelled and care should be taken as exact

plates should be laid as indicated on the plan. A placement of a plate at a wrong

position may cost you disassembling the whole steel tank. It also ensures the inlet

flange, washout, outlet flange and overflow are placed rightly.

The side plates are then also bolted with rubber plug in between and fixed to the

bottom assembly. They should be fixed firmly enough so that they cannot fall off.

The bolts should not be fixed very tightly as yet since there’s need to adjust plates

when assembling the tank.

Angle linings are also fixed to the side plates on which a ladder is tightened with

ropes as scaffold to assemble the top plates and roof of the tank.

After assembling all the side plates, enter the tank and fix the joint and corner

covers at the bottom assembly and also the tank stays and tank cleats on the side

plate assembly. The tank stays are to ensure the tank is square while the cleats and

covers to limit leakage at points of placement.

The roof cover gables, stiffeners, apex and rafters are fixed and the roof cover plates

bolted onto them.

The internal and external ladders are fixed and then all the bolts are finally

tightened very firmly to finish the tank.

20


Tightening bolts. Fixing tank cleats.

Placement of the tank roof.

21


CHAPTER FIVE: PIPE WORK

5.1 Introduction A pipe is a closed conduit generally of circular section used to carry water or any other

fluid, but in this case it was water. When a pipe is running full, the flow is under pressure

but when it isn’t running like in sewers or culverts, the flow is not under pressure but

rather atmospheric pressure exists in the pipe.

Flow in pipes is therefore due to a pressure gradient. It’s due to this gradient that pipes of

different pressure ratings (PN 6, PN 10, and PN 16) were used across the profiles- the

transmission and distribution mains.

PN stands for Pressure Nominal the pipe can support with water at 20oC and only 3

pressure grades of the pipes were used in this project

PN 6- maximum pressure 6 bar where

PN 10 – maximum pressure 10 bar 1 bar = 105 Pascals

PN 16 – maximum pressure 16 bar

Pipes were supplied by GENTEX and Simba Multiple Industries Ltd both located in

Kampala, Uganda

5.2 Surveying for pipes Before pipes were laid, surveying would be done to provide profile details for the water

mains. Pegs would then be set up along the water mains to guide the plumbers while laying

pipes.

The main instruments used were a dumpy level and a total station. A dumpy level was used

over small areas mainly to get the elevation/height differences over an area while the total

station was the key instrument used for setting out.

Below are steps taken in the levelling process and use of both instruments.

5.2.1 Levelling process of a Dumpy Level

This is a simple procedure on how to set up the dumpy level;

- The tripod has its legs firmly fixed into the ground trying to ensure that the tripod

table is relatively flat and the instrument is then mounted on to it.

- After mounting the instrument onto the tripod, using the three foot screws, u may

now level the instrument by rotating the telescope to be by parallel a given set of

two foot screws and after which these screws are turned gently and simultaneously

in opposite directions until the bubble is brought to the center of its runs. If this is

attained, the telescope is then made perpendicular to the third foot screw and this

screw is again rotated until the bubble returns to the center of its run again.

22


- If this is attained, the telescope is then rotated to face any other direction and if the

bubble settles back to the center of its run, the leveling procedure is done. If it does

not return to the center of its run, the procedure is then repeated.

- The final step is to focus the onto the target using the eyepiece lens to view the

target clearly and then using the objective lens to attain fine cross hairs and those

that are not blurred. This is done to eliminate parallax.

After following all the above steps, the instrument is now ready to use and the only thing

left to do is to take the readings by focusing on the staff.

23


5.2.2 Using and Levelling of the total station

A total station consists of a theodolite with a built-in distance meter (distancer), and so it

can measure angles and distances at the same time. In order to describe the position of a

point, two coordinates are required.

Preparation for use

Levelling

- Place the tripod approximately over the ground point.

- Inspect the tripod from various sides and correct its position so that the tripod plate

is roughly horizontal and above the ground point.

- Push the tripod legs firmly into the ground and use the central fixing screw to secure

the instrument on the tripod.

- Switch on the laser plummet and turn the footscrews so that the laser dot or the

optical plummet is centred on the ground point; it was usually the centre of a nail of

a temporary bench mark

- Centre the bull’s-eye bubble by adjusting the lengths of the tripod legs.

24


- After accurately levelling up the instrument, release the central fixing screw so that

you can displace it on the tripod plate until the laser dot is centred precisely over

the ground point.

- Tighten the central fixing screw again.

Setting up: Orientation Method

- Set Job: Select “Set Job” and enter in respectively

- SetStation: The screen then goes to SURVEYING and select “SetStation” and enter in

respectively (see below).

You can also enter the height of the Total Station above the survey point by measuring

this with a tape measure and entering it. This will make all height measurements

relative to the survey point, rather than the Total Station. Height was either 1.300m or

2.150m depending on how the prism was used.

Set Orientation:

Since some temporary bench marks (TBMs) had already been set, this process was to

be a confirmation of the accuracy of the levelling of the instruments. Focus at the prism

at the second point should give a reading which is within the acceptable error of the

previous reading. Swing the Total Station so that the cross-wires are aligned with the

mark on the cross-wires at the second point. If the error is acceptable. Continue.

25


Select Start: after the above process, select “start” and begin taking your reading while

neatly noting them in a book.

After taking the readings, switch it off, carefully unscrew it from the tripod and pack it

in its box including the prism.

An example of information developed from the surveying process is recorded as shown

below;

PROFILES - PRIMARY DISTRIBUTION MAINS

Nyaravur to Pakwach

Chainage (m)

Ground level

Pipe Details

Fittings

0+000 1040.1

20

33

m x

O

D1

10

P

N1

0

Tee at Nebbi - Packwach Rd Junction

1+157 1019.2

2+033 1016.1 Tee to Parombo before BPT to Pakwach

2+033 1016.1

16

00

m x

O

D6

3

PN

6

3+633 955.88

3+633 955.88

16

07

m x

O

D5

0

PN

10

5+240 928.21

5+240 928.21

30

40

m x

O

D5

0

PN

16

end of survey; WO + end cap

8+280 884.3

8+280 884.3

13

91

m x

O

D5

0

PN

16

9+671 883.99

9+671 883.99

87

0m

x

OD

40

P

N1

6 end of design pipeline; alternative

WO + end cap 10+541 877.21

26


Types of pipes

5.3 High Density Polyethylene (HDPE) pipes They are very popular for water pipes and were used on the distribution mains. HDPE

pipes were black in colour and sunlight is not a concern if black pipe is used.

Carbon black, utilized in most all HDPE pipe is the most effective ultraviolet stabilizer and

therefore, black is the recommended pipe color for exposed long term service or storage.

5.3.1 Advantages of HDPE pipes

Leak free: HDPE pipe is normally joined by heat fusion. Butt, socket, sidewall

fusion and electrofusion but we were using butt welding which creates a joint

that is as strong as the pipe itself, and is virtually leak free.

Corrosion, abrasion and chemical resistant: HDPE has excellent corrosion

resistance and is virtually inert. It does not need expensive maintenance or

cathodic protection. It offers better overall resistance to corrosive acids, bases

and salts than most piping materials. In addition, polyethylene is unaffected by

bacteria, fungi and the most “aggressive” naturally occurring soils.

Excellent Flow Characteristics: Because polyethylene is smoother than steel,

cast iron, ductile iron, or concrete, a smaller PE pipe can carry an equivalent

volumetric flow rate at the same pressure. It has less drag and a lower tendency

for turbulence at high flow

Lightweight and flexible: HDPE pipe is produced in straight lengths or in coils.

Made from materials about 1/8 the density of steel, it is lightweight and does not

require the use of heavy lifting equipment for installation. It reduces the need for

fittings and performs well in earthquake-prone areas. Since HDPE is not a brittle

material, it can be installed with bends over uneven terrain easily in continuous

lengths

Ductility and toughness: HDPE pipe and fittings are inherently tough, resilient

and resistant to damage caused by external loads, vibrations, and from pressure

surges such as water hammer. Even in cold weather polyethylene pipe is

tolerant to handling and bending.

27


5.3.2 Joining of HDPE pipes

I was able to take part in one process of connection known as butt welding and it’s

described below;

Equipment;

Butt welding machine (heating plate, pipevice/alignment jig, shaver), stool, diesel

generator, metallic saw

Welding procedure

Preparation: The HDPE pipes were first pulled out from the pits if they were

already lengthened out. So they appear out above the ground level and make sure

you have sufficient working space.

Assembling the pipe vice; here, a stool would be placed on a fairly flat ground. It’s

the working platform where the butt welding equipment is assembled. The pipe vice

would then be tightened by the bottom clamps so that it flashes with one side of the

stool edges.

The alignment of the pipe: The pipes were aligned when they are clamped into the

mirror welder in such a way that the surfaces are in the same plane (parallel) to

each other. The HDPE pipes were positioned directly into the welding machine.

Since sometimes pipes of different diameters were used, we would install the

correct adapter insert for the size of pipe diameter to be used and tighten them to

the machine. Then position the pipe in a way that approx. 50mm is protruding

behind the last clamp. By doing this, you will have approx. 10 to 15mm to shave

from, and the remaining 25 to 30 mm should be sufficient for welding. Once the

pipes were placed in position, the top clamps were closed. It is important to tighten

the top clamp nuts evenly in order to get a totally circular pipe, an even clamping

pressure must be achieved. Then, make the first dry matching (press the two pipes

to each other) and check the amount of shaving that will be required.

The shaving of the surfaces of the pipe ends: After the dry matching was

completed, we opened up the pipes and introduced the shaver. Then pressed the

two pipes together, and shove until a continuous strip of HDPE was peeling off on

both sides of the shaver. Once constant peeling off was observed, release the

pressure on the pipes and separate the pipes. Do not stop shaving until the pipes are

apart. Remove the shaver, match the pipes again, and check the pipe for proper

alignment. Sometimes, even when continuous peeling off is achieved on each side of

the shaver, the pipes do not match properly. This is normally due to the clamps,

which are pressing on to the pipe with different pressures. Re-tightening the nuts

slightly on either side would be one solution. The assistants would then hold the

pipes in this position and the shaver slowly removed.

28


Heating of surfaces: after the shaving process, a heating plate was then introduced

between the pipes and the pipes tightened on both sides of the plate. The generator

as the power source would then be started and the pipes heated up to melt.

Depending on the pipe wall thickness, the heating process was taking 10-

15minutes.but care would be taken so it doesn’t melt beyond what’s required.

Fusion of surfaces: with the assistants still holding the pipes, the generator would

be stopped and the heating plate quickly removed and placed somewhere safe so it

doesn’t burn up anyone. This is where you would temporarily shut your ‘heat feeling

senses’ in the hands and quickly join the melted bit. It was usually done by two

people. They stand opposite each other and place the melted bit with two fingers as

you move along the pipe to form a straight raised line at this point. It’s permanent.

Cooling of weld joint: Cooling time is the time in which the pipe has to be left

undisturbed. Under no circumstances would the clamps be opened or the pressure

released until the cooling time has elapsed. You keep touching the pipe so you can

know if the pipe has cooled down.

After cooling disassemble the equipment and place the pipe into the pit so that this

single unit of pipes is buried. When HDPE pipe is buried, the temperature of the

system becomes much more stable than an above ground pipeline and therefore will

exhibit far less dimensional change. In most systems, buried HDPE pipe does not

move after it is buried. All pipes expand and contract with change in temperature.

The key is management of the resultant thermal strain. Also buried pipelines

usually do not move due to soil friction. However, thermal effects must be

considered for above grade applications.

29


Melting the pipes using a heating plate Shaving the pipe surfaces with a shaver

5.4 STEEL PIPES They were used above ground level and not like uPVC pipes which were buried

underground after laying. Since they were heavy about 750kg (OD 280mm pipes), 8

energetic workers would carry one pipe to the desired place. In a day, they could probably

transport 2 pipes on their shoulders to site. They were frequently used where pressures

are high, large diameter pipe is required and above ground. Steel pipe has high strength

and stiffness (modulus of elasticity).

It is comparatively inexpensive, easy to install, and more easily transported than ductile

iron pipe; however, steel pipe cannot withstand the external loads that DIP can. Because it

is metallic, steel pipe is subject to corrosion and the corrosion is oftentimes more severe in

steel pipe than DIP. Though cement-mortar lining and coating is often used to protect both

the interior of the steel pipe

Steel pipe can be joined together using different methods but we were only exposed to

welding, use mechanical couplings or fittings and flange connections.

Mechanical coupling will be described below in connection of uPVC pipes in section 5.6.2

but below is the welding process.

30


5.4.1 Joinery by welding

It’s a very simple procedure and quick especially if experienced personnel are used. I was

involved in pipe laying in the bushes at walkable distance of about 3km from the treatment

plant at Kei in a place called Abindu.

Welding is used for pipe laying above the ground where there are bends that’s; both

horizontal (right or left turns) and vertical (change in gradient e.g. when rising and going

down a rock or bridge crossing).

Equipment; angle grinder, tape measure, welding torch, generator, welding electrode,

sledge hammer

Procedure

The pipes would be delivered to the point where the pipes are required.

The welder would then measure out the length required and mark on two sides of

the pipes so then using a small rope or edge of the tape measure thread to make a

round mark around the pipe so he could make a regular cut while using the angle

grinder.

After this process, his assistants would then twist the pipe under his instruction and

hold it so he would start welding the two stub ends of the pipes using a welding

torch until he’s done. For welding, a welding electrode is placed in the mouth piece

of the welding torch and the torch left to close it up. The generator is started and so

the torch gains voltage to melt the electrodes onto the pipes.

After cooling, the welded part is painted to minimize corrosion of that part

NOTE:

The above procedure is for pipes on straight level e.g near washout valves or break

pressure tanks, but for the cases where there’s change in slope like when there’s need to

move over a hill, the procedure is slightly different as described below;

The welder was very experienced so he could just look at the slope and visually

determine the angle between the about-to-be welded pipes and then measure out

the length of the pipe to cut. In sloppy cases, the stub ends of the pipes would be cut

so they slant. Then the welding would proceed as above described and painting

done later.

Since the use of steel pipes can’t be accurately determined on profiles, after the

day’s work, the foreman would move a few meters ahead to find out if there’s need

of any steel pipes so that they can be delivered the following day.

31


Using an angle grinder. Welding using a welding torch.

5.4.2 Joinery by Flange connections.

Flange connections were used to join pipes mainly in the distribution mains where steel

pipes met at full length and for pipe work at the treatment plant.

Procedure

A mark is made around the steel pipe using the end if a tape measure to enable

regular cutting using the angle grinder.

A flange is placed at the stud end of the pipe, and using a square, it’s welded onto

this end so that it’s at 90o to the pipe.

Do the same to the second pipe.

Leave the pipes to cool down and then using spanners you can bolt the pipes.

32


Bolting pipes. Checking connection with a square.

5.5 DUCTILE IRON PIPES Ductile Iron Pipe (DIP) has a high degree of dependability due to its high strength,

durability, and impact and corrosion resistance.

DIP can also be installed in a wide variety of soils and trench conditions and can be easily

cut to length in the field.

Disadvantages to DIP are; it is heavy and therefore more difficult to install than other

types of pipe and it is also more expensive that other pipe types.

DIP is usually furnished with cement-mortar lining for corrosion resistance. It’s also

commonly painted or wrapped with polythene on the exterior of the pipe for external

corrosion protection depending on soil corrosivity.

These pipes were used to tap water from the gabion barrages at the water intake and by

the time I arrived for internship they had already laid the pipes so the knowledge I

acquired of connection was by consultation and interaction with the plumbers. The pipes

were simply fixed by spigot and socket joints and concrete pedestals were cast at the

centre of the pipes to counter balance the pressure built up by the water from the gabion

barrages.

The base rocks of the concrete pedestals were predominantly chalks and since they are

porous and couldn’t sufficiently bear the weight on them, they had to be removed and

replaced with relatively stronger rocks which had features of basalts just by visual

inspection. Basalts has greater bearing strength than chalk.

33


Spigot and socket joint at a ductile iron pipe

5.6 uPVC (Un-plasticised Polyvinyl Chloride) Unlike metallic pipes, uPVC pipes do not rust or corrode over time. It is also lightweight and

therefore easier to handle and install than other types of pipe. The primary method of wear

is by exposure to sunlight and heat, which begin to warp the pipe and cause damage. This is

why uPVC pipe is normally used underground or in basements where there is no sunlight

to damage the pipes.

Another disadvantage is that careful attention must be paid during construction to avoid

rocks or sharp objects coming into contact with the pipe.

5.6.1 Joinery of uPVC pipes

The procedure of laying uPVC pipes to each other is as described below;

For joinery to be quicker, all the pipes would first be offloaded and placed on the

ground just over the dug pits. This was done with reference to the profiles so that

space is left where due, especially if there was a break pressure tank along laying

line.

The form of joinery was the spigot and socket joint, of which the socket is the

female end and spigot the male end which is chamfered.

34


On delivery, the socket had a plastic ring and rubber gasket the plastic ring is a

protective to the rubber ring and would be removed as disposed while the rubber

ring was to keep this joint watertight after inserting in the spigot. The offset from

the ends is 250mm length and indicated with a black marker around the spigot.

A log stick with a rope tied on it would then be wound on top of the pipe with the

spigot end so that when lowering the pipe the log rests across the ends of the pit so

then we could control the movement of the pipe using just the rope.

Let’s call the pipe with the spigot end, pipe A, and the other pipe with socket end

(where pipe A is inserted) as pipe B.

Dust particles were then cleaned out of the socket to reduce costs on future

clogging, and using liquid soap, the socket of pipe B would be lubricated by

spreading the soap inside.

Pipe A was then slowly lowered in the pit and pipe B was placed over the pit but log

sticks placed below it so it doesn’t fall in just yet so the pipes would be in a straight

line and easy to push in since uPVC isn’t flexible.

Pipe B would then be just inserted into pipe A and with about two assistants on the

spigot end of pipe B, a quick push force would be applied here so that the spigot

would enter into the socket and the black mark just covered. If not, then pipe B was

pulled out and the push force applied again.

Lubricating the socket with liquid soap. Lowering pipe with rope.

NOTE:

After joining uPVC pipes, they were placed into 1.2m pits backfilling done.

35


5.6.2 Joinery of uPVC to steel pipes

Here mechanical couplings (Viking Johnson couplings) referred on site as M fittings were

used. The coupling consists of two metal rings, two rubber rings and a neck.

Procedure

Both pipes would be assembled so that they flash by dry matching them.

The coupling was then disassembled and the components fitted in the pipes so that

there’s a metal and rubber ring on each pipe, and a neck in one of the pipes.

The pipes were then raised or lowered so that the open ends flash.

The neck would then be dragged so that its centre is at the joint where these pipes

meet and then the rubber piece would be dragged into the neck and the metal ring

with hole for bolting would also be added.

For firmness of the coupling to avoid future bursts, consecutive bolts were fixed

interchangeably i.e. the head and points of a bolt would face oppositely on

consecutive bolts.

Parts of a coupling. Tightening bolts of the coupling

36


5.7 Thrust blocks Thrust blocks in water mains are created for the following ways

Where the pipe changes direction horizontally or vertically

Where the pipe changes size

At dead end

At restrictions; and

When valves or hydrants are closed quickly

Thrust blocks are used at these locations to prevent damage to the pipe caused by

unsupported pipe movement.

Tees, bends, plugs, hydrants, and other appurtenances and fittings require thrust blocks to

restrain the pipe. If thrust blocks are not provided, the pipe would be free to move causing

joint separation, leakage and damage to other connected structures or pipes.

5.7.1 Casting of Thrust Blocks

The following was done to create thrust blocks.

Formwork was assembled at any of the above mentioned location and firmly

propped.

Formwork bore against undisturbed soil since disturbed soil is subject to

compression upon loading and therefore could not be used as a bearing surface.

Plain unreinforced concrete was used to construct blocks. It only comprised of sand,

cement and water.

This concrete was prepared by hand mixing. The hand mixing process is explained

in detail in chapter six section 6.2.3

A cast thrust block.

37


CHAPTER SIX: FORMWORK AND CONCRETE This section includes both formwork and concreting done at the treatment for the rapid

sand filter and clear water tank.

6.1 FORMWORK ASSEMBLY Formwork is a structure usually temporary used to contain poured concrete and to mould

it to the required dimensions and support until it’s able to support itself

Good formwork should satisfy the following requirements:

It should be strong enough to withstand all the types of dead and live loads

It should be rigidly constructed, efficiently propped and braced both horizontally

and vertically so as to retain its shape

The joints in the formwork should be tight against leakage of cement grout

Construction of formwork should permit removal of various parts in desired

sequences without damage to the concrete

The material of the formwork should be cheap, easily available and should be

suitable for reuse.

Formwork should be set accurately to the desired line and levels should have

plane surface

It should as light as possible

The material of the formwork should not warp or get distorted when exposed to

the elements

It should rest on firm base.

Timber boards in metal frames was the formwork used all through and propped by timber

poles.

The timber used was well seasoned, light in weight, free from loose knots and easily

workable with nails without splitting.

38


6.1.1 Formwork assembly of the clear water tank.

Two sets of formwork were used for casting of the clear water tank. Timbers frame

formwork was used for two 1.5m lifts of the clear water tank which was 3100mm high. The

remaining 100mm would be catered for in the second lift.

Concrete spacer blocks (spacers) were fitted onto the reinforcement at approximate

intervals of 1000mm vertically and horizontally at the ends of each board. The boards were

cleaned and brushed to smoothen the surface so as to ease flow of concrete during casting

and vibration. The steel work is then finally aligned for verticality.

A timber piece was nailed onto the shores which were of the same height as the first cast

lift. The shuttering was then lifted and carefully laid onto the shores and smoothened end

facing the spacers. It was adjusted horizontally by pushing and pulling then vertically by

wedging till it was at exact marked position and height.

The board was then tied to the reinforcement using binding wire. Timber pole supports

were laid horizontally at the bottom. These poles were cut with a mitered end with length

slightly longer than required distance of support. L- Shaped cuts were made in the

supporting earth and small timber pieces were laid here in the L-shape to receive the bases

of the timber poles and props.

The timber poles are rested in these pieces and the other side laid on the formwork frame

then knocked by the sledge hammer into position thereby giving very rigid support to the

frame. . The formwork is plumbed using vertical bubble in the spirit level. Small timber

pieces known as gauges with length equal to thickness of wall are fitted at top of the

formwork to maintain the thickness of wall during casting. The spaces between the

formwork are fitted with cement paper to reduce on bleeding of concrete leading to honey

combs.

6.1.2 Formwork assembly for rapid sand filter

The procedure of assembling the formwork was similar to that of the clear water tank

mentioned above. What only changes is just the dimensions and detalis of the two

structures.

6.1.3 Formwork for dwarf walls

Reinforced concrete dwarf walls of thickness 230mm and 1m above the existing ground

level were used as the base support for the water reservoir tanks in Oweko, Nyaravur and

Goti-Madi.

At Oweko, there was revision of the size of water reservoir tank so there was need to

increase length since the dwarf walls for the previous tank size had already been cast.

39


The procedure is simple and similar to that of the clear water tank explained above only

that this is just to a small scale.

Sawing poles. A u-bar to hold the formwork

Formwork assembly for tank dwarf walls. A gauge placed at top of formwork

40


6.2 CONCRETE PREPARATION AND CASTING This section comprises of all the stages that were taken to prepare concrete, cast, finish and

cure columns, foundation pads and retaining walls.

Concrete is a composite material composed of proportioned amounts of cement, sand (fine

aggregate) and (coarse) aggregate bonded together by water.

6.2.1 Concrete production

The treatment plant site had 2 operating mixers; both run by using diesel fuel. On each

mixer there were at least 10 workers. 4 to load aggregate, 2 to load sand, 1 on cement, 1 to

deliver water, the mixer operator and the others had to cast the concrete at the required

positions.

Casting concrete for both the clear water tank and rapid sand filter took one day each. It

was at this stage that I mastered how to hold the spade for easy loading. I also leant how to

operate the mixers as I was able to differentiate between the gear levers used and the

whole process of operating the mixers.

For the rapid sand filter, casting was done by a loader and placed on a platform from

whence it would be loaded on wheel barrows or directed by spade to the desired place. For

the clear water tank, a wheel loader wasn’t needed as the mixers were just near the point of

casting.

Specification of the concrete ratios for the clear water tank and rapid sand filter was 1:1.5:2

(2:3:4) being cement:sand:aggregates and usually 2 gallons of water though the amount of

water would be varied on observation by the site engineer as sometimes it wouldn’t be

accurately proportioned.

Sand used- lake sand, aggregates used – ¾ inch and ½ inch, cement used - tororo

multipurpose, power max, and superset brands. For blending purposes for the aggregates 3

parts were of ¾ inch aggregate and 1 part of ½ inch to increase the density of the concrete.

Depending on particular output, this mix is at times slightly varied to produce desired end

product say if result has too much aggregate, 1 box of ¾ inch is replaced by ½ inch.

Ratios are achieved by use of batch boxes of equal volume to 1 bag of cement with

dimensions of 0.33m * 0.33m * 0.33m that is length, width and height. These have long

handles attached which facilitate their carrying. But this method later proved to be slow,

hence adopting use of wheel barrows to approximate the mix ratios

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6.2.2 Making spacer blocks

The ratio used was 1:1 that is cement:sand. Formwork for the spacer blocks was composed

of a marine board and joined with timber pieces so that the spacers will have a thickness of

50mm. Cement and sand is placed at the spacer formwork and mixed thoroughly until it

has a uniform color and water added, mixed thoroughly. The mixture is then poured onto

the formwork and spread all over the formwork. A flat level board is then passed over the

formwork and in case there are any gaps, the excess gaps is then filled with the swept away

mortar. A hollow cylindrical metal form of diameter about 200mm was then pressed into

this mortar in rows. When u press the form, you would ensure that a knock sound is heard

as a confirmatory that this form has touched the bottom part of the board. Then circles are

then cut out using the tip of a trowel. Finally, binding wires are folded and placed into each

block. They are then cured after drying usually after a day

Spacer blocks

6.2.3 Concrete production by Hand Mixing

This section describes the steps for mixing concrete by hand. This was mainly done for

concrete required on a small scale for example concrete required for fencing.

Steps

A fairly impenetrable ground is chosen. This can be a place where concrete was

formerly cast and has already hardened

Sweep the area so as to remove materials that may contaminate the concrete like

polythene bags.

Wet this area by pouring some water on this ground.

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Then place the coarse aggregate to form a circular bottom layer, sand is the next

layer and finally spread cement over them so that it’s the top most layer.

Dry mix the materials with a spade so that components are evenly distributed and

making sure a uniform colour is achieved.

Mixing water is first done to half the volume of this mixture. This is to avoid the

concrete from setting/hardening before it can be used.

The left amount can then mixed with water and used accordingly.

NOTE: The procedure is the same for cement mortar only that for mortar, we don’t mix coarse

aggregate. Mortar was used for casting spacer blocks and finishing honey combed concrete

surfaces of walls.

6.2.4 OPERATING THE MIXER

The following explains how the mixers were used/operated;

Before you start it, Ensure that the unit is mechanically sound, fuel is sufficient and

engine oil level okay. You can also check tyres for appropriate inflation

Select a firm and level working area and protect surrounding surfaces. Ensure that

the area does not contain any hazards may impact on mixer operation. Turn on fuel,

close choke, and pull rope using smooth action. Once started, open choke and allow

to warm up.

The mixer is loaded with all the dry materials and blended for about 5 minutes until

homogeneous as you pour in some water evenly over the mix.

Tip the mixer horizontally so it doesn’t spill out concrete and you check the

consistency. This can take 5-10 minutes. Continue mixing and add in the remaining

water so the concrete is neither stiff nor clumpy.

The drum is the tilted so it can pour concrete in the wheel loader’s bucket or on a

platform from which concrete can be loaded on a wheel barrow for casting.

After the day’s work, empty mixer drum of contents. While still wet, add water. Then

allow to revolve or wash interior and exterior clean.

Clean up work area and place mixer in a secure area

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6.2.5 Casting process

Before the rapid sand filter walls would be cast, the site engineer would first come and

check the firmness of the formwork and the props. In case there are small timber pieces

and or other stray particles in the formwork, measures would be taken to remove them.

The workers would get onto the top of the sheathing with fueled vibrators, spades, wheel

barrows and other material needed. Cement was then mixed in a water can and then

poured into the formwork. Using the spades, concrete would then be directed into the

formwork or onto the wheel barrows to required locations. The poker would then be

inserted into the formwork and vibration was done. The vibrator operator made sure

vibration isn’t over done at one place as this led to expansion of the formwork at that point

and incase he observed failure of the formwork, the case would immediately be reported to

the site engineer or the carpenters. Otherwise vibration continues until the level required

was reached. As you approach the top of the formwork, the gauge would be removed so it

isn’t embedded in the formwork. The top surface would then be finished with a trowel.

Casting and vibration of concrete

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6.3 Tests on concrete Test results may be used for quality control, acceptance of concrete, or for determining the

concrete strength in a structure for purposes of scheduling construction operations like

form removal, evaluating adequacy of curing and protection afforded to the structure.

A test result is an average of at least two standard cured strength specimen from the same

concrete sample and tested at the same age usually 7 or 28 days for a compressive strength

test.

6.3.1 SLUMP CONE TEST

This is an empirical test for measuring the workability of concrete. This helps also in

identifying the consistency of concrete as it’s related to workability.

Apparatus

A sample of freshly mixed concrete (about half a wheelbarrow full)

A wheelbarrow and shovel

A flat steel plate about 600 x 600 mm by 3 mm thick

A metric rule or tape measure

A scoop

A steel tamping rod, 16 mm in diameter by 600 mm long

A standard slump mould

Procedure

These are the steps I was taking to carry out this test;

To obtain a representative sample, take samples from two or more regular intervals

throughout the discharge of the mixer but I chose to take at intervals of five. But

don’t take samples at the beginning or the end of the discharge.

Load the concrete in the wheelbarrow and mix it thoroughly with a trowel. Wipe all

the tools including the mould and base plate with a damp cloth.

Put the steel plate down on a level place so that it is firm, and then put the slump

mould on it with the narrow end at the top. Stand on the footpieces.

Dampen inside of cone and place it on a smooth, moist, non-absorbent, level surface

large enough to accommodate both the slumped concrete and the slump cone. Stand

or, foot pieces throughout the test procedure to hold the cone firmly in place.

Fill the slump mould in three layers of about equal depth. Tamp through each layer

25 times with the rounded end of the tamping rod.

The last layer should more than fill the mould. After tamping the last layer, strike off

the excess concrete, using a sawing and rolling motion of the tamping rod, so that

the mould is completely filled and level

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Immediately lift cone vertically with slow, even motion. Do not jar the concrete or

tilt the cone during this process.

Invert the withdrawn cone, and place next to, but not touching the slumped

concrete. (Perform in 5-10 seconds with no lateral or torsional motion.)

Lay a straight edge across the top of the slump cone. Measure the amount of slump

in inches from the bottom of the straight edge to the top of the slumped concrete at

a point over the original center of the base.

The slump operation can be completed in less than 5 minutes. Discard concrete and

don’t use in any other tests.

The slump would then be recorded.

The specified slump on site was 75mm for the clear water tank and rapid sand filter.

Tamping concrete with steel rod. Measuring slump with tape measure.

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6.3.2 COMPRESSIVE STRENGTH TEST OF CONCRETE

This is one of the most key strength tests carried out on concrete. It depends on the

proportions of materials in the concrete. In this experiment, strength tests are carried out

on concrete cubes to represent the average compressive strength of cast concrete

How to make the 150-mm concrete cubes

Three cubes were needed for each test. And they were to be tested at 7 days and at 28 days.

So we would cast eight cubes instead of six (3+3) just in case some are poorly handled

Apparatus

• A sample of the concrete (about half a wheelbarrow full)

• A wheelbarrow and a shovel

• A scoop

• Eight standard moulds for each test

• A steel tamping rod, 600 mm long with a diameter of 16 mm with one rounded end.

• A steel float

• Pieces of writing paper (absorbent paper) for labels

• Mould release oil

• Grease

This is the PROCEDURE we were taking;

Check that; moulds are clean and do not have dust or dirt on them, the joint faces

have been greased, they are assembled in the right way, and the bolts are tight.

Smear release oil very thinly on the inside faces of the moulds.

Place the moulds on a firm, level surface.

Pick up fresh concrete from the concrete mixer by the wheel barrow at various

intervals say after every 5 mixes.

Mix the concrete well in the wheelbarrow so it has a uniform texture.

Fill the moulds with concrete in 50 mm layers.

Tamp each layer at least 45 times with the rounded end of the tamping rod to get

the air bubbles out.

The last layer should more than fill the mould. After tamping the last layer, use the

steel float to strike off the surface of the concrete so that it is level with the top of the

mould.

Write the following on a label for each cube; the structure that’s been cast (usually

in short form i.e. R.S.F for rapid sand filter or C.W.T for clear water tank), the date

when the cube is made, company name or your name initials.

Gently press the label onto the top of the cube.

Cover the cube with damp sacking followed by a sheet of plastic and store it in the

shade, away from wind and where it will not be disturbed.

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After 12 hours

Loosen all the bolts on the mould and the sides of the mould and remove them.

Put the cubes into water. The temperature of the water should be 25°C–29°C.

Leave the cubes covered with water until they are taken to the testing laboratory.

Clean the moulds and assemble them again.

6.3.3 Using the Compressive Strength test Machine

Three concrete cubes are removed from the curing tank and wiped with a cloth so

that they are in surface dry condition.

After transportation to the laboratory, the weight of a cube is taken and read from a

weighing scale and recorded in table 2 shown below.

Using a tape measure the dimensions of the concrete cubes are taken just for

confirmation.

We used a hand operated compressive strength test machine which works on

hydraulic system in which the pressure is supplied through a hand operated pump

like handle. The lowered platen is on the hydraulic ram and the upper having a

sphere-shaped seating is adjustable.

In this the machine, the load is applied through the hydraulic assembly by moving

the handle down to impose a compressive force.

The bearing surface of the compression platens of the machine is first wiped clean of

any loose material that could have stayed due to the previous test.

A concrete cube is placed onto the lowered platen and locked firmly with the top

one.

A gentle force is then applied by hand using the handle onto the specimen until its

resistance to the applied load breaks down and can no longer sustain a greater load.

This value is recorded in table shown below.

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Where:

U.C.S was used to represent Ultimate Compressive Strength

DATE

MADE

DATE

TESTED

DIMENSION

(mm)

WEIGHT

(kg)

DENSITY

(kg/m2)

CRUSHING

LOAD (kg)

U.C.S

(N/m2)

30/06/2015

SAND

FILTER

WALLS

8/7/2015 150x150x150 8.9 2637 285 12.7

8.9 2637 435 19.3

8.8 2607 385 17.1

Table 2 above shows the results of the rapid sand filter wall concrete that was cast.

Calculations for the above table

Density= weight (kg/m3)

Volume of concrete cube

Ultimate Compressive Strength (U.C.S) = maximum crushing load x 10 (N/m2)

Cross sectional area of specimen

Observations and conclusion

For the above table the first value is far more different and less than the others. This could

be because of the following reasons;

Poor casting of the cubes.

Poor sample could have been taken i.e. one with high water content.

Weighing a concrete cube Crashing a concrete cube

49


CHAPTER SEVEN: WATER TREATMENT PLANT

The water treatment plant was located in Kei and which according to the surveying made

was at an altitude of 34m lower than the water intake.

Water treatment is provided to remove constituents from raw water which may pose a risk

to public health or are undesirable in finished water. The water treatment process is

intended to remove suspended and dissolved solids included:

Raw water screening;

Coagulation;

Flocculation;

Sedimentation; and

Filtration.

Final chlorination.

This chapter provides a general description of each of these processes and information on

the level of turbidity reduction that is commonly achieved through each.

7.1 Raw water screening The screen was at the water intake and is meant to prevent large rocks, sticks, and other

debris from entering the treatment system.

It’s well explained in chapter four.

7.2 Coagulation Coagulation was to be done in the dosing room. Coagulation is the process of conditioning

suspended solids particles to promote their agglomeration and produce larger particles

that can be more readily removed in subsequent treatment processes. In many cases,

dissolved organic substances are adsorbed on the surface of suspended solids particles and

effective coagulation can be an effective step in their removal as well. The particles

suspended in raw water typically vary widely in size.

Colloidal size particles typically carry an electrical charge. When the suspended particles

are similarly charged, the resulting repulsive forces between particles tend to “stabilize”

the suspension and prevent particle agglomeration. The process of coagulation is complex

and may involve several different mechanisms to achieve “destabilization”, which allows

particle agglomeration and enhances subsequent removal.

Coagulation is typically accomplished through chemical addition and mixing. Following

coagulation, the processes of flocculation, sedimentation, and filtration are used to remove

the “destabilized” particles from suspension.

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The chemicals used for coagulation (coagulants) include; aluminum or iron salts and

organic polymers. But on this site, the chosen coagulant was alum.

Rapid mixing is utilized at the constriction from the chlorination room and is part of the

coagulation process to distribute the coagulant chemicals throughout the water stream. It

is extremely important that the coagulant chemical be distributed quickly and efficiently

because it is the intermediate products of the coagulant reaction that are the destabilizing

agents. This constriction is shown below:

7.3 Flocculation Flocculation is the physical process of agglomerating small particles into larger ones that

can be more easily removed from suspension. Flocculation is almost always used in

conjunction with, and preceded by coagulation. During the coagulation process the

repulsive forces between solids particles are reduced or eliminated. Flocculation is the

process of bringing the destabilized particles into contact with one another to form larger

“floc” particles. These larger particles are more readily removed from the water in

subsequent processes.

Flocculation is generally accomplished by mixing the destabilized suspension to provide

the opportunity for the particles to come into contact with one another and stick together.

The amount of time the water spends in the flocculation process is a key performance

parameter.

Adequate time must be provided to allow generation of particles sufficiently large to allow

their efficient removal in subsequent treatment processes. The optimum particle size may

vary significantly depending on the downstream treatment processes utilized. For

example, on our site where sedimentation is to be used, large floc particles are typically

desirable because they tend to settle out of suspension readily.

So the flocculator was divided into a continuous series of channels called baffles which

cause the water to which the chemical has been added to flow around the ends of the

baffles through numerous channels. The channels are made so narrow so that the flow

velocity is sufficient to prevent the formation of deposits.

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7.4 Sedimentation/Clarification Sedimentation is the process by which solids are removed from the water by means of

gravity separation. In the sedimentation process, the water passes through a basin in

which relatively quiescent conditions prevail. Under these conditions, the floc particles

formed during flocculation settle to the bottom of the clarifier while the “clear” water

passes out of the basin. The solids collect on the slanting basin bottom and are removed by

opening the sludge drain.

The clarifier is divided into three sections (concreted tanks) in which velocity currents are

reduced to the point where gravity is the predominant force acting on the water/solids

suspension. Under this condition, the difference in specific gravity between the water and

the solids particles causes the solids particles to settle to the bottom of the basin.

A flocculator with baffles.

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7.5 Filtration Like clarification, filtration is a process in which solids are removed from water and

substantial turbidity removal is achieved. Optimization used prior to the filtration process

will control loading rates while allowing the system to achieve maximum filtration rates. In

fact, filtration is the final step to achieve turbidity reduction in most water treatment

operations. The water leaving the filtration process should be well within turbidity limits.

Rapid Sand Filtration was to be used. Here, water enters the filter unit above the media

and flows by gravity downward through the filter media to the underdrain or collection

system, where it is removed from the filter. When the filter media becomes clogged with

solids it is cleaned through a “backwash” process.

In the backwash process water, and in some instances, air is introduced to the filter at a

relatively high rate through the underdrain system. The water and air flow upward

through the media, expanding the media bed and creating a scrubbing or scouring action

which removes solids accumulated on the media surface and in inter-particle sites within

the media bed. After passing through the media bed, the backwash water and the solids it

contains are removed from the filter with a series of collection troughs.

7.6 Final Chlorination This is done after the filtration process in the Clear Water Tank. The clear water tank has

baffles to create large surface area for chemicals (chlorine, e.t.c.) to dissolve. In this case,

the baffles are more widely spaced as the turbidity is expected to be far less than in the first

flocculation process.

After this process, water can then be transmitted to the water reservoir tanks and we

started by connecting the pipes from the treatment to Oweko first and later, Nyaravur plus

Goti:Madi.

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CHAPTER EIGHT: OTHER WORKS This chapter includes works that were done outside this main project and includes

activities I got involved in by visits to other sites.

They include;

GROUND WATER TECHNOLOGIES (BOREHOLES) A borehole is any hole drilled or dug into the sub-surface for the purpose of extracting or

investigating the material at that particular point. In our case the material is water.

Borehole water is from an aquifer defined as a formation that contains sufficient saturated

permeable material to yield significant quantities of water to wells.

Boreholes have been the main option for rural water supply for a long time though MWE is

currently better and cheaper water supply systems like gravity water flow supply schemes.

8.1 Implementation

Steps that are followed in the implementation of water and sanitation project. (MWE-

DWD, July 2012)

Planning phase.

This includes the following basic considerations

i) Hold advocacy meetings at both the district and sub-county level at the outset

creating awareness and demand for water and sanitation services.

ii) Identify and appraise community priorities at various levels and integrate them into

the Local Government development plans.

iii) Feed back to the communities on the approved plans/choices.

Pre-Construction mobilisation and training phase

As part of the community needs assessment to guide in decision making on technology

choice, allocation of facilities and input planning for sustainability.

Verification of water site access, during mobilisation and sensitization of communities

apply deliberate strategies to target participation of men and women with successful

committees stipulating their roles and commitments towards O & M to be fulfilled.

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Implementation-Construction Phase

Continued mobilisation and sensitization of communities on; ownership, and

maintenance of facility.

Training of WSCs geared towards preparation of communities to fulfil their roles

during the mobilization and the O&M follow-up phase.

During construction monitor the quality of materials and work being done.

Commissioning of the facility should be carried out to emphasize the ownership and

CBMS aspects.

8.2 Ground water investigation Methods used in investigation of ground water include

Maps- here topographical and geological maps aid in the investigation of ground

water survey though this is to a lesser extent.

Vegetation survey; here particular vegetation which is identified with round water

on being seen in an area then there will be ground water underneath it.

Local knowledge: for example people who live in area always have some of this

knowledge and if asked they are able to tell where in the area one can locate

ground water.

Remote sensing: this is not widely used because it is expensive and avails less

information as far as ground water investigation is concerned.

Geophysics which is widely used

Drilling

Geophysics has the following methods;

Resistivity

Conductivity

Seismic refraction

Magnetic resonance method

But I’ll talk about electrical resistivity because it’s what was used at the site we visited.

8.2.1 Resistivity method

This uses direct contact method of electrodes placed into the ground to measure the

resistance to electricity. It works on the principle that high resistance to current flow

implies no conductor and low resistance means presence of conductor in this case water.

Water is a better conductor of electricity than the rock; hence water bearing strata will

have a lower resistivity than similar strata that are dry.

Results of current and resistance are plotted on a VES (Vertical Electrical Sounding) paper

and depending on the points considered results are discussed and most suitable point

considered.

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8.3 Drilling. Some of the drilling methods include Hand auger drilling, jetting, sludging, percussion

drilling but of interest is rotary drilling which was done on site.

8.3.1 Rotary drilling

The equipment was provided by the contractors who are ICON Projects Ltd

There are two methods used in drilling and these are; Water/mud drilling and Air

drilling. The method of drilling depends on the type of soils. For the visited site the

adopted method was mud rotary drilling, this basically used water which was being

supplied by a water bouzer and at the closing stages air drilling was employed to remove

any hammer cuttings that would have remained and usually done by a compressor.

Types of pipes used

a) Screen pipes: These are usually fixed next to the gravel in the water struck zone

after it being filtered it finds its way through to the static water level. They are then

connected to the plane pipes.

b) Plane pipes: These are solid pipes through which water flows to the outlet.

Drilling environments:

1) Sedimentary formation/un consolidated rock formation: This formation consists of

minimal or no rocks at all and mainly consist of sediments and clay of different

colour among others.

2) Basement formation/consolidated rock formation: this is that area that mainly

consists of rocks. Method of drilling in such an area is the air rotary using a drilling

rig

It was observed that the area visited was of a sedimentary formation which was a

justification for mud drilling. This was done with the aid of a polymer which mainly helps

to reduce the viscosity of water during drilling.

8.4 Development of the well. This is basically aimed at removing the dirt/cleaning the well. This is done by allowing the

water to settle for at least 72 hrs.

8.5 Determining the yield: Yield simply means the amount of water flowing in a given period of time. This is done to

help the test pumping team to be able to determine the size of the pump they need while

carrying out test pumping and to also obtain the efficiency of the drilled borehole.

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8.6 Test pumping. This is usually done mainly for three hours for the purpose of determining the static water

level( this is the final level water reaches after settling in the pipes), water strike level(level

of water before the installation of the pipes) and the dynamic water level(Level of water

reached after three hours of pumping). The different levels help in the calculations of the

draw down.

Quality checks are done about the water and recommendations made on whether water is

safe for use, else the project is abandoned at this stage.

Drilling process.

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8.7 Installation. There are two major types of installation methods and these being: - hand pump and the

production well (usually pumped using a submersible pump connected to a generator).

8.7.1 Procedure of installation

This procedure is according to U3 HAND PUMP INSTALLATION AND MAINTENANCE

MANUAL (Feb 2000) by Directorate of Water Development for use in Uganda

Equipment

Connecting rod vice, wire brush, pipe wrench, spanners, ball pen hammer, non-toxic oil, self

locking clamp, hack saw, file

Procedure

Platform construction

The ground was leveled and square pit around the casing pipe is dug in preparation to cast

concrete. The casing pipe is kept covered at this stage to stop any contamination of the well

because of the ongoing work above the ground.

A concrete mix of 1:2:4 is prepared and the poured into the square pit around the casing

pipe at a depth of 50mm.

The well cover is removed and stand assembly placed over the casing pipe ensuring the

assembly is vertical using a spirit level. Concrete is then filled in the pit rammed so as to

construct the platform while concrete is still wet. Check the top flange so it’s levelled. Cover

this stand assembly to avoid entrance of particles like stones into the tube well.

Mild steel platform shuttering is laid over the levelled pump pedestral and prepare the

ground for constructing as per design. Cast the concrete, complete the platform and cure it

for atleast 7 days making sure there’s limited access around by using say thorny bushes.

Installation of riser pipes

The riser pipes here are of stainless steel and they are first laid out all the threads checked

and cleaned with a wire brush.

Apply putty then yarn following the trend of the threads on the pipe. Socket is then

screwed onto the pipe end and then a nipple into the socket end to prevent buckling when

tightening the socket onto the pipe with a pipe wrench. Test this cylinder in a bucket of

water if check valve leaks and screw down plunger making sure it’s kept in a safe dust free

place.

The first pipe is then screwed into cylinder using jointing compound, yarned and tightened

fully. This pipe is then lowered slowly and insert a self-locking clamp. The clamp and pipe

wrench is used only at the thickened ends of the pipe.

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Bring the next riser pipe and screw with the first one and tighten at the thickened end and

socket. It’s then lowered down gently and the thickened end locked by opening the clamp.

Tighten the pipes and lowered down riser pipes with the help of pipe lifting spanners.

Apply non-toxic grease to water tank coupler threads, screw water tank with last pipe

threads and tighten fully. Screw last pipe with water tank.

Lower down water tank with riser pipes gently and place on stand flange. Unscrew and

remove tank pipe lifter.

Installation of check valve, plunger, connecting rods and pump head.

Connection rods are prepared by applying Vaseline and ensuring that threads are good and

clean. 20mm hexagonal rod coupler are screwed onto one end of each rod and insert rod

centralisers. You again screw 50mm hexagonal rod couplers after the centralisers and

tighten these couplers.

The check valve assembly is then screwed by two threads with the plunger assembly and

tighten the first connecting rod with the plunger rod. The plunger assembly is then lowered

and screwed with check valve assembly into the riser pipes and tightened with water tank

riser coupler.

The connecting rods are lowered and the rod vice positioned on water tank so they are

tightened. The rod lifter is screwed on the threads so that he check valve is unscrewed and

left in the bottom cylinder cap.

The connecting rod is then pushed to bottom most position so we can mark it in level with

top of water tank and cut the rod at this mark File and thread top of the connecting rod as

you lubricate with oil and insert middle flange.

Screw chain coupler on to the top rod threads and insert chain into head. You can then

tighten pump head, middle flange and water tank. Grease is then applied to the chain.

Cover bolts are fully tightened and finally the inspection cover fixed.

The pump is now ready for use and it can thus be commissioned to the target population.

8.8 Types of borehole wells 1) Light weight/shallow wells: Less than 30m.

2) Extra deep wells: More than 30m of heavy handle.

3) Production wells. Used to supply water on a large scale,

Yield: Is defined as the amount of water pumped or supplied per hour.

8.9 Post construction/O&M phase. Provide for follow up programmes to encourage good O&M practices for example

refresher trainings, promotion of latrine construction et al.

Monitor aspects of water in terms of; functionality of facility, behaviour change,

quality and quantity of water, benefits realised from improved services.

Take any remedial action necessary according to findings. (MWLE, 2004)

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CHAPTER NINE: PROBLEMS, SOLUTIONS AND CONCLUSION

9.1 PROBLEMS: The following are outlines of the problems on site:

Language barrier

There were so many workers and they wouldn’t specialize in the works as they could

change sites according to the day’s work. This made it so hard to monitor them efficiently.

Young human labour was used on some sites.

Most of the sites were located deep in the bush and this usually delayed work.

Access of vehicles to some sites wasn’t possible so the workers had to walk an average

distance of 3km daily to get to these sites.

The steel pipes were too heavy and machinery like excavators couldn’t reach the sites

where they were to be laid. This called for human labour to carry these pipes and under

extreme pressure, they would carry a maximum of 2 steel pipes (OD 280mm) a day.

Rainwater which caused flooding in excavated pits sometimes would delay work.

Break down of machines; there was continual servicing of the concrete mixers, tippers and

the loaders.

Shortage in supply of materials

Formwork needed continual supervision while casting the concrete as sometimes it would

not be firm enough

Great variation at the concrete mixing area where varying quantities of sand and aggregate

volumes and types of cement are used at times intentionally and at other times due to

tiredness and laziness of labour under poor supervision.

The method of casting structures at the treatment plant in two lifts produced a defected

joint which creates a region of weakness.

Wildlife always put the workers’ lives at stake. Oftentimes we met snakes, scorpions,

salamanders, thorny bushes etc. but importantly is, I was able to overcome fear of some of

these reptiles/amphibians. Below is a snake we killed at one of the sites.

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9.2 SOLUTIONS A few basic words in the local language can be learnt so as to communicate with the

workers.

Foremen should allocate each worker to a specific site so that they are easier to

monitor. In case one misses then it’s easy to notice.

The laborers should be paraded before being employed to avoid incidences of

employing young workers.

The existing footpaths to the bush should be widened so that vehicles can also be

able to access them to transport both pipes and workers.

New machinery should be purchased and the old ones sold out or disposed off.

Formwork needed continual supervision while casting the concrete as sometimes it

would not be firm enough

Great variation at the concrete mixing area where varying quantities of sand and

aggregate volumes and types of cement are used at times intentionally and at other

times due to tiredness and laziness of labour under poor supervision.

The method of casting structures at the treatment plant in two lifts produced a

defected joint which creates a region of weakness.

Extreme care should be taken while working in the bush and all workers should be

very close to each other as they have a greater force to oppose any wild creature

that may come up. “Two heads are better than one.”

9.3 CONCLUSION The industrial training was so educative that I learnt a lot of things which I do think they

are helpful in my career and through these trainings I think I shall be able to learn more

things relevant to my profession and hope to achieve the best .

The condition at the site was generally good and we were able to achieve what we could

and the administration management was also good from the resident engineer, to head of

foreman and to the workers.

Machinery such as steel grinder, welding machine were used compared to the manual labor

which accelerated the progress in work and I think they will be able to achieve a lot from

the project if pace of work is maintained.

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APPENDIX 1 DRAWINGS

Treatment plant site layout

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Plan of the Flocculator.

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Clarifier plan.

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APPENDIX 2: PHOTOS

The resident Engineer supervising works.

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Formwork assembly for clear water tank.

Pipe work at the treatment plant

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Pipe work at the treatment plant. Finishing excavation of a pit.

Sawing for thrust block formwork. Laying steel pipe over bridge crossing.

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A painted welded point. Lifting steel pipe using a chain block.

Carrying a uPVC pipe. Stacked uPVC pipes.

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Operating a dumper.

Commissioning a borehole. A site meeting at Leosim Hotel

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THE END

THANK YOU FOR READING!!!!