Studies on the Degradation of Used Engine Oil by Bacterial Isolates from Used Engine Oil Contaminated Soil

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