ABSTRACT

Biodegradation of used engine oil contaminated soil using bacteria from such soils was undertaken. Three principal bacteria species, Staphylococcus, Bacillus and Pseudomonas were selected from among the soil isolates and tested for their potency as biodegraders of engine oil in the contaminated soil over a period of 28 days. Results of the preliminary soil analysis showed sand fractions in the range of 64.53% to 68.83% silt 9.50% to 18.33% and clay 16.67% to 22.93%. the soil was also rich in organic matter 3.57% to 4.04% and average moisture content in the range of 21.70% to 23.96% during bioremediation with Bacillus  innocula, the bacteria load varied between 1.3x107 cfu/g to 2.5x107 cfu/g in the control soil of site A while the remediated soil for the same site were in the ranges of 1.3x107 cfu/g to 1.09x108 cfu/g at the end of the remediation with a reduction of soil content from 4.67% to 2.39% representing 48.8% remediation. Similarly, remediation of 38.21% (2.80% to 1.73%) and 48.47% (4.27% to 2.20%) were recorded in site B and C respectively. The levels of remediation with Pseudomonas species were 53.30% (4.67% to 2.19%), 40% (2.80% to 1.68%) and 50.40% (4.27% to 2.12%) in the soils of site A, B and C respectively. The bacteria load varied from 1.7x107 cfu/g to 3.4x107 cfu/g in the control soil of site A while the remediated soil for the same site was in the range of 1.7x107 cfu/g to1.55x108 cfu/g. the bacteria load of the test soil of site B varied from 1.3x107 cfu/g to 3.0x107 cfu/g while the remediated soil ranges from 1.3x107 cfu/g to 1.64x108 cfu/g of soil in the same site, while that of site C varied from 1.9x107 cfu/g to 3.1x107 cfu/g for control soil and 1.9x107 cfu/g to 1.71x108 cfu/g for the remediated soil. During bioremediation with Staphylococcus innocula, the bacteria load varied between 1.3x107 cfu/g to 2.4x107 cfu/g in the control soil of site A while the remediated soil for the same site was in the range of 1.3x107 cfu/g to 1.04x108 cfu/g while bacteria load varied between 1.2x107 cfu/g to 1.02x108 cfu/g in the control soil of site B while the remediated soil for the same site was in the range of 1.2x107 cfu/g to 1.32x108 cfu/g and the bacteria load of site C varied from 1.5x107 cfu/g to 3.5x107 cfu/g for the control soil while that of the remediated soil varied from 1.5x107 cfu/g to 1.23x108 cfu/g at the end of the remediation with a reduction of soil content from 4.67% to 3.46% representing 25% remediation for test soil from site A, similarly remediation of 31% (2.8% to 1.91%) and remediation of 33% (4.27% to 2.86%) were recorded for site B and C respectively. Slight but significant variations were recorded in the extent of bacteria biodegradation of the used engine oil contaminated soil with Pseudomonas species being more potent than the Bacillus species and Staphylococcus species as bioremediaters of the soil.

TABLE OF CONTENTS 

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of tables v

List  of tables viii

List of figures ix

Abstract x 

CHAPTER ONE

1.0 Introduction 1

1.1 Aim and Objectives 3

CHAPTER TWO

2.0 Literature Review 4

2.1 Engine Oil 4

2.2 Used Engine Oil 4

2.3 Effects of Used Engine Oil on Soil Physical Properties 5

2.4 Effects of Used Engine Oil on Soil Chemical Properties 6

2.5 Effects of Used Engine Oil on Soil Health 8

2.6 Biodegradation 10

2.6 Hydrocarbon Degrading Bacteria  12

2.6.1 Bacterial Isolates 12

CHAPTER THREE

3.0 Materials and Methods 15

3.1 Source of Materials 15

3.2 Sample Preparation 15

3.2.1 Sterility of glasswares 15

3.2.2 Preparation of media 16

3.3 Methods of Analysis 16

3.3.1 Isolation of bacteria 16

3.3.2 Characterization of bacteria isolates 16

3.3.2.1 Colony features 16

3.3.2.2 Microscopic features 17

3.4 Biochemical features 17

3.4.1 Catalase production test 17

3.4.2 Coagulase production test 18

3.4.3 Urease test 18

3.4.4 Citrate utilization test 18

3.4.5 Oxidase test 18

3.4.6 Carbohydrate Utilization test 19

3.4.7 Indole Test 19

3.5 Identification of Isolates 19

3.6 Determination of Soil Physiochemical Parameters 19

3.6.1 Determination of total organic carbon 20

3.6.2 Determination of particle size distribution 20

3.6.3 Determination of total exchangeable bases 20

3.6.4 Determination of Ca2+ and Mg2+ by EDTA 21

3.6.5 Determination of pH 21

3.7 Isolation of Oil Utilizing Bacteria 21

3.8 Degradation of Used Engine Oil 22

3.8.1 Determination of residual oil in soil 22

3.8.2 Determination of Bacteria Growth 23

CHAPTER FOUR

4.0       Results 24

CHAPTER FIVE

5.0 Discussion, Conclusion and Recommendations 38

5.1 Discussion 38

5.2 Conclusion 39

5.3 Recommendations 40

References 41

Appendix 43