Water supply and Sewerage services in urban areas have in the past commonly been provided by monopolized Municipal Councils under the previous Local Government Ministry. As part of a general move by the sector to shift to market-led systems by restructuring the sector, a new paradigm emerged to transform water utilities into more modern service delivery companies that emphasize on operational and financial sustainability. This report presents findings on attributes of a well-run Water Treatment Plant as of KIWASCO and attempts to identify important factors that influence its performance. The scope is also largely oriented to water utilities that serve urban communities, but with varying characteristics and service objectives.
TABLE OF CONTENTS
PRELUDE………………………………………………………………………………………………………….....................7
OBJECTIVES, AUDIENCE AND SCOPE OF THIS REPORT…………………..............................................................7
METHODOLOGY .....................................................................................................................................................7
OVERVIEW OF KIWASCO HISTORY AND OPERATIONS .....................................…………………….....................8
ORGANIZATIONAL STRUCTURE OF KIWASCO.......................................................................................................8
COMMERCIAL SERVICES DEPARTMENT.................................................................................................................9
FINANCE DEPARTMENT…………………………………………………………………………………...…........................9
HUMAN RESOURCES AND ADMINISTRATION DEPARTMENT...................................................................................9
INTERNAL RISK AND AUDIT DEPARTMENT.............................................................................................................10
TECHNICAL SERVICES DEPARTMENT...................................................................................................................10
SUPPLY CHAIN DEPARTMENT................................................................................................................................11
OVERVIEW OF WATER TREATMENT PROCESSES..............................................................................................12
( i) Intake…………………………………………………………..………………………….……...…........................12
(ii) Arrival at the Plant…………….………………………….….………………………………...….........................12
(iii) Sedimentation……………………………………………………………………………………............................12
(iv) Filtration ………………………………………….……………………………….................................................13
(v) Chlorination .........................................................................................................................................13
CHAPTER 1 INTRODUCTION…………….................................................................................................................14
CHAPTER 2 WATER TREATMENT………………………..........................................................................................14
2.1 SOURCES AND CHARACTERISTICS.....................................................................................................14
2.2 PRE-TREATMENT……………………………...........................................................................................15
2.2.1 pH ADJUSTMENT………......................................................................................................................15
2.2.2 WATER STABILIZATION………............................................................................................................16
2.2.3 COAGULATION & FLOCCULATION ....................................................................................................16
2.2.3.1 JAR TEST…………………………………............................................................................................16
2.2.3.2 COAGULATION…………………………………………………………….....................…………………...22
2.2.3.3 COAGULANTS ………………………………………………..................................................................25
2.2.3.4 FLASH MIXING/RAPID MIXING……...................................................................................................28
2.2.3.5 DETENTION
TIME….........................................................................................................................29
2.2.3.6 TEMPERATURE
EFFECTS………………………………….................................................................30
2.2.3.7 ALUMINIUM RESIDUALS
...................................................................................................................31
CHAPTER
3
SEDIMENTATION................................................................................................................................32
3.1
DEFINITION......................................................................................................................................32
3.1.1 FACTORS AFFECTING
SEDIMENTATION.....................................................................................32
3.2 SLUDGE
HANDLING.........................................................................................................................35
CHAPTER
4
FILTRATION.....................................................................................................................
..................37
4.1 PURPOSE OF
FILTRATION..............................................................................................................37
4.2 FILTRATION
PROCESS.....................................................................................................................37
4.2.1 MECHANICAL
STRAINING...............................................................................................................37
4.2.2
ELECTROLYTIC..............................................................................................................................38
4.2.3 CHEMICAL
REACTIONS..................................................................................................................38
4.3 TYPES OF
FILTERS...........................................................................................................................38
4.3.1 THE SLOW SAND
FILTER................................................................................................................38
4.3.2 THE RAPID SAND
FILTER...............................................................................................................38
4.3.3 DIRECT
FILTRATION.......................................................................................................................39
4.4
BACKWASHING...................................................................................................................................39
4.4.1 METHODS OF FILTER
BACKWASHING...........................................................................................41
CHAPTER
5
CHLORINATION.....................................................................................................................................42
5.1 PURPOSE OF
CHLORINATION..............................................................................................................42
5.1.1 SOURCES OF
CHLORINE...................................................................................................................43
5.1.2 CALCULATING THE CHLORINE
DOSE….............................................................................................44
5.2 REACTIONS OF
CHLORINE...................................................................................................................44
5.2.1 OTHER USES OF
CHLORINE..............................................................................................................46