Chemical and Bacteriological Assessment of Piped and Borehole Water in Dar Es Salaam City, Tanzania

ABSTRACT 

This study was undertaken to determine the quality of water by determining the e physicochemical parameters, chemical parameters and bacteriological properties of piped water, and boreholes water in Dar es Salaam city, as well as determination of the seasonal variation of raw water quality. Piped water samples were purposively collected at the point of treatment to the point of use. However all the operational boreholes water samples were sampled. Chlorine, conductivity, temperature, pH and Total dissolved solids were analyzed direct from the sites while Colour, Turbidity, Alkalinity, Total hardness, Alminium, Iron, Manganese, Ammonia, Nitrates, Chlorides, Calcium, Total coliforms and Faecal coliforms were analyzed in the laboratory following the standard procedures for water analysis. The results showed that, piped water was of better quality compared to that of the borehole as most of the values analyzed were within the maximum permissible limit according to WHO (2008) and current Tanzanian standards. The major contaminants in underground water were calcium derived geochemically, faecal coliforms and total coliform attributed to anthropogenic activities. Values for conductivity were much high for the borehole samples, with the highest mean value of (1241.5±1086.98) ps/cm recorded at Mzimuni Primary School while for the piped was (I52.35±48.65)ps/cm recorded at Upper Ruvu plant. The low values from the piped water were due to efficient water treatment process done by DAWASCO. The chemical elements analyzed in piped water, were all below the permissible limit except aluminium which had the highest mean value of (I.43±1.17)mg/l at House hold 1 which was above 1.0mg/I of that of Tanzanian standard maximum permissible limit of drinking water whereas those obtained from the borehole, were within the permissible limit. The highest mean value for total coliform was 3.66±0.58/lOQml from the piped water at City Botanical Garden and 3.33±2.08/100m for House hold 3, and 3±1/lOOmI, from the boreholes at Shauri Moyo. The highest value for faecal xiv coliform was (2.33±1.15)/100ml, from the piped water at House hold 3 and (0.68±0.58)/i 00ml from the borehole at Shauri Moyo and Kigogo Pr School. Conductivity was correlated with TDS (rs =0.556 at p = 0.05), Ammonia (rs= 0.74, at p= 0.05) and Calcium (rs= 0.603 at p= 0.05). Colour was also correlated with Manganese (rs= 0.574 at p= 0.05) Calcium was correlated with TDS (rs= 0.603). Turbidity (rs= 0.50), Ammonia (rs= 0.550) and Total hardness (rs=0.777) Most of the values obtained during dry season were within the maximum allowable limits. High values were observed during wet season than in dry season and were attributed to the surface runoff from the farming areas that contained fertilizers. The study concluded that, most of the potable water sources in Dar es Salaam city especially that under the control of DAWASCO was of good quality and can be used for normal human consumption especially for domestic purposes (portable).

TABLE OF CONTENTS

DECLARATION

APROVAL

DEDICATION III

ACKNOWLEDGEMENT

LIST OF TABLES VIII

LIST OF FIGURES

ACRONYM

DEFINITION OF TERMS

ABSTRACT

CHAPTER ONE I

INTRODUCTION 1

1.1 BACKGROUND I

1.2 PROBLEM STATEMENT 3

1.3 GENERAL OBJECTIVE 3

1.3.1 Specific objectives 3

1.4 SCOPE OF THE STUDY: 3

1.5 SIGNIFICANCE OF THE STUDy: 4

CHAPTER TWO 5

REVIEW OF THE RELATED LITERATURE~ 5

2.0 INTRODUCTIoN 5

2.1 SoURCES AND STATE OF PORTABLE WATER 5

2.1.1 The state of water quality in Tanzania 7

2.1.2 Existing water system in Dar Es Salaam City 8

2.1.3 Water treatment process 9

2.2. PHYSICAL AND CHEMICAL CHARACTERISTICS OF PORTABLE WATER AND THEIR STANDARD 12

2.2.1 Physicochemica~ characteristic of water quality ofpotable water 12

2.2.2 Chemical Elements 16

2.2.3. Chemical pollution 20

2.2.4 Tanzanian and WHO Drinking water standards 20

2.3 MICROBIOLOGICAL ASPECT OF WATER QUALITY 21

2.3.1 Total coilforms 23

2.3.2 Faecal cailform 24

CHAPTER THREE 25

MATERIALS AND METHODS 25

3.0 INTRODUCTION 25

3.1 REsEARCH DESIGN 25

3.2 DESCRIpTION OF THE STUDY AREA 25

3.3 DESCRIPTION OF THE SAMPLING SITES 27

3.4 SAMPLE SELECTION 29

3.5 SAMPLING PROCEDURES, PREPARATION AND LABORATORY ANALYSIS 30

3.5.1 Sampling procedures 30

3.5.2 Determinations ofphysicochemical parameters 31

3.5.3 Determinations of chemical elements 32

3.5.4 Microbiological Examinations 33

3.6 STATIsTIcAL ANALYSIS 34

LANGELIER SATuI~TI0N INDEX (LI) - METHOD 8073 34

Correlation 34

MULTIVARIATE ANALYSIS; CLUSTER, AND PRINCIPLE COMPONENTANALySIS (PCA).... 35

CHAPTER FOUR 36

RESULT AND DISCUSSION 36

4.0 INTRODUCTION 36

4.1. ASSEsSMENT OF THE PHYSICOCHEMICAL CHARACTERISTIC OF PORTABLE WATER 36

4.1.1 Chlorine (Cl) 37

4.1.2 Electrical conductivity 38

4.1.3 Total dissolved solids 39

4.1.4 pH measurements 40

4.1.5 Water temperature 41

4.1.7 Alkalinity 42

4.1.8 Total hardness 43

4.2. DETERMINATION OF THE CHEMICAL PARAMETERS OF POTABLE WATER 44

4.2.1 Alminjum 44

4.2.2 Iron 46

4.2.3 Manganese 46

4.2.4 Ammonia 48

4.2.5 Nitrates 48

4.2.6 Chlorides 49

4.2.7 Calcium 49

4.3. ASSESsMENT OF BACTERIOLOGICAL PARAMETERS OF PORTABLE WATER 50

4.3.1: Total coliforms and faecal coliforms counts for piped water 50

4.3.2: Total coliforms and faecal coliforms counts from the boreholes 51

4.3.3 Effect of Chlorine on the Total coliform and Faecal coliform counts in piped water.

52 4.4: VARIATIoNS OF RAW WATER AND TREATED WATER QUALITY CHARACTERISTICS 53

4.4.1: Variation of raw water quality during rainy and dry season 53

4.4.2: Raw water percentage removal 57

LANGELIER SATURATION INDEX (LI) 59

Piped water sources 59

Borehole water sources 60

Distribution and Source Apportionment of Contaminants In Piped and Borehole Water

61 Piped water sources 61

Borehole water sources 66

CHAPTER FIVE 73

CONCLUSIONS AND RECOMMENDATIONS 73

5.0 INTRoDUCTION 73

5.1 CONCLUsIONS 73

5.2 RECOMMENDATIONS 74

5.3 AREA FOR FURTHER RESEARCH 75

REFERENCES~ 76

APPENDICES .86

APPENDIX 1: INTRODUCTORY LETTER 86

APPENDIX II: WATER TEMPERATURE, TOTAL DISSOLVED SOLIDS, HARDNESS OR ALKALINI-ry T..87

APPENDIX III UPPER Ruvu RAW WATER INTAKE 89

APPENDIX IV: UPPER Ruvu TREATMENT PLANT 90

APPENDIX V: PAPER 91

ABSTRACT 91

INTRODUCTION 92

MATERIALS AND METHODS 93

Study area 93

Water sampling 94

Determination ofphysical and chemical characteristic of water 95

Microbiological examination 95

STATISTICAL ANALYSIS 95

LANGELIER SATURATION INDEX (LI) - METHoD 8073 95

Correlation 96

MULTIVARIATE ANALYSIS; CLUSTER, AND PRINCIPLE COMPONENT ANALYSIS (PCA).... 96

RESULTS AND DISCUSSION 97

Borehole water sources 97

Piped water sources 105

CONCLUSION 110