EVALUATION OF THE POTENTIAL OF RED SOIL TO ENHANCE SOLAR DISINFECTION OF DRINKING WATER

TABLE OF CONTENTS

DECLARATION ............................................................................................................................. 2

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

TABLE OF CONTENTS ....................................................................................................... ......... 4

List of Tables ........ .................................................. .................................. ............ ........................... 6

List of Figures .................................................................................................................................. 6

LIST OF ABBREVIATIONS: .................... .................................................................................... ?

Abstract ............................................................................................................................................ 8

CHAPTER ONE .. ............................................................................................................................ 9

1.0 INTRODUCTION ............................................................................................................... . 9

l.I BACKGROUND INFORMATION ..................................................................................... 9

I.2. PROBLEM STATEMENT ................................................................................................. IO

I.3. HYPOTHESIS ............................................................................... ..................................... tO

1.4. PURPOSE OF STUDY ............................ .......................................................................... IO

1.5. SPECIFIC OBJECTIVES ................................................................................................... I 0

I.6. STUDY QUESTIONS ..................................................................................... ................... II

1.7. STUDY JUSTIFICATION ................................................ ........................ ......................... ! I

1.8. SCOPE OF STUDY ..... , ... ............................... .............................. ...... .................... , .......... I I

CHAPTER TWO ........................................................................................................................... 12

2.0 LITERATURE REVIEW ............................................. ..................................................... I 2

2. 1 IRON-RICH SOILS TN UDANDA ................................................... ............................. 12

2.2. Water Hygiene and Pathogens in Uganda ....................................................................... I 2

2.3. THE CHEMISTRY OF SODIS: ......................................................................................... I 3

2.4. E. Coli Detection and Use as a Biomarker for Disinfection ............................................ I 4

CHAPTER THREE ....................................................................................................................... 15 . .

3.0 MATERIALS AND METHODS ....................................................................................... 15

3. 1. STUDY AREA: ...................... ............................................................................................ I5

3.2. STUDY DESIGN ............................................................................................................... 15

3.3. STUDY SAMPLE SIZE ..... ................................... ............................................................. I5

3.4. MATERIALS AND METHODS .............. ................................ ......................................... 15

3.4.2 Establishment of ph influence in water steri I ization using soi1. .................................. 16

3.4.2. 1 Materials .................................................................................................................. 16

3.4.2.2 METHODS .................................................................................................................... 16

3.4.3 APPROPRIATE CONDITIONS REPEATED UNDER UV RADIATTON .................... I6

3.4.3.1 MATERIALS ............................................................................................................ 16

3.4.3.2 METHOD ..... ............................................................................................................. 17

3.5 Data Analysis ............................................................................................................. .......... l7

CHAPTER FOUR ......................................................................................................................... 18

4.0 RESULTS ............................. ..... ......................... ................................................................ 18

4. 1 Potential of red soil to enhance water disinfection under LED Light.. ........................... l8

4.2 Influence of pH in the sterili zation potential of red soi1 ................................................. 20

4.3 Potential of red soil to enhance solar disinfection of water with optimum pH ............... 2 1

CHAPTER FIVE ................................................................. ........................... ............................... 22 . .

5.0 DISCUSS ION .......................... ................................. ............ .............................................. 22

5. 1 Water disinfection under LED light using soil. .............................................................. 22

5.2 PH influence in water sterili zation using soil. ............................................................... 23

5.3 Role of UV light. ............................................................................................................ 23

CHAPTER SIX ...................... ........................................................................................ ................ 24

6.0 Conclusion and Recommendations ................................................... .................................. 24

REFERENCES ......................................... ..................................................................................... 25 

Abstract 

Background: Clean drinking water in developing countries is a major challenge due to the high microbial load that makes it unsafe for human consumption, thus showing the need to develop novel technologies that would lead to increase accessibility of safe drinking water for the poor. Aim: This stud y to evaluate the potential of red soil in the enhancement of the solar disinfection of drinking water. 

Materials and Methods: Three experiments were set up, each containing 99ml of distilled water, 76 ~I of hydrogen peroxide, 50 ~I of orange 2dye. One without the photo catalyst, one with ferric oxide (400mg) and the third with red soil (800mg), the mixture was placed in a conical flask stirred with a magnetic stirrer and exposed to LED light, lemon juice and UV light. Samples were taken at different intervals i.e. 30, 60, 90 minutes, centrifuged and absorbance was taken at 483 nm using a spectrometer. Bacterial growth was conducted using mckonky agar and colony forming units were counted. 

Results and Discussion: The study showed that soil led to a greater decrease in absorbance in the water than in ferric oxide under LED light which would have been due to production hydroxyl radicals has been shown to have the ability to lead to disinfection of water through a reduction in bacterial growth. A reduction in pH by the actions of lemon juice led to increased degradation activity by Fe3 + showing the role of low pH in disinfection due to the reductions in bacterial growth in after exposure. On exposure to UV light, low degradation was seen due to increase in turbidity thus showing that optimum degradation is feasible in UV under less turbid conditions. 

Conclusion and Recommendations: Soil enhanced solar water disinfection under optimum conditions as it was able to minimize bacterial growth. However, changes in these parameters such as pl-1, and turbidity led to decreased activity. There is need to determine the mechanism of action through which this activity is done.