ABSTRACT

This study was aimed at determining the microorganisms associated with biogas produced from cassava peels and cow rumen fluid. The study adopted the use of two (2) substrates combination namely Cassava Peels (CP) and Cow Rumen Fluid (CRF).  1kg of cassava peels were collected from a grating centre in Umuahia North while about 2 litres of cow rumen fluid was collected from Ubakala Abbatoir Market which were taken to Microbiology Laboratory for analysis within 24 hours of sample collection. These samples were anaerobically digested and used in 1:1 ratio. Standard microbiological methods were used to screen the isolates and the wastes substrate for biogas production. The study isolated eight (8) bacteria species from the biodigested cassava peel and cow rumen fluid blend. The mean anaerobic count ranged from 1.13 x 106cfu/ml to 7.10 x 106cfu/ml. There was a considerable difference in the concentrations of different parameters in the daily slurry sample, observed mean chemical oxygen demand (COD) and biological oxygen demand (BOD)  values at the 28th day of digestion was 1016 mg/L and 207mg/L, pH range 7.1-8.8, mean gas volume produced from cassava peel/cow rumen fluid blend was 2.09Ld-1. The findings of the study concluded that anaerobic co-digestion process has synergistic effects to increases biogas yield from the substrate. The study recommended need for more studies in organic blends in biogas production and cautions approach to handling biodigesters as pathogenic organisms proliferate there.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables vii

List of figures viii

Abstract ix

CHAPTER ONE

1.0 INTRODUCTION 1

1.1.1 Aim of the Study 5

1.1.2 Objectives of the Study 5

CHAPTER TWO

LITERATURE REVIEW

2.1 Renewable Energy 6

2.1.1 Solar Energy 6

2.1.2 Wind Energy 7

2.1.3 Biomass Energy 8

2.1.4 Tidal Power 9

2.1.5 Geothermal Energy 9

2.2 Biogas 10

2.2.1 Overview of biogas production 12

2.2.2 Biogas Development in Africa 15

2.2.3 Biogas Development in Nigeria 15

2.3 Anaerobic Digestion (AD) 16

2.3.1 Classification of Anaerobic Digestion (AD) System 17

2.3.2 Accelerants/Additives for AD 17

2.3.2.1 Green Biomass 18

2.3.2.2 Biological Additives 18

2.3.2.3 Chemical Additives 19

2.3.3 Stages of anaerobic degradation of organic wastes 22

2.3.3.1 Hydrolysis 22

2.3.3.2 Acidogenesis (Acidification Phase) 23

2.3.3.3 Acetogenesis 24

2.3.3.4 Methanogenesis 24

2.4 Anaerobic co-digestion 25

2.5 Anaerobic digesters 25

2.5.1 Capacity of Anaerobic Digesters 26

2.5.2 Basic considerations for digester construction 26

2.5.3 Types of Digesters 27

2.5.3.1 Continuous and Batch Digesters 27

2.5.4 Siting of Biogas Digester 32

2.6 Cassava Peels 32

2.6.1 Biogas Production from Cassava Peel 32

2.7 Cow Rumen Fluid 34

CHAPTER THREE

MATERIALS AND METHODS

3.1 Study area 36

3.2 Sample collection 36

3.3 Sample preparation 37

3.4 Media preparation 37

3.5 Analysis of samples 37

3.5.1 Determination of Physicochemical Characteristics 37

3.5.1.1 Determination of Temperature 37

3.5.1.2 Determination of pH 37

3.5.1.3 Determination of Dissolved Oxygen (D.O) 38

3.5.1.4 Determination of Biological Oxygen Demand (BOD) 39

3.5.1.5 Determination of Chemical Oxygen Demand 39

3.5.2 Microbial Composition and Mean Count 40

3.5.2.1 Fungi Identifications 40

3.5.2.2 Bacteria Identification 40

CHAPTER 4

RESULTS AND DISCUSSION

4.1 Results 42

4.2 Discussion 46

CHAPTER 5

CONCLUSION AND RECOMMENDATION

5.1 Conclusion 49

5.2 Recommendations 49

REFERENCES

APPENDIX