Microorganisms Associated With Biogas Produced From Cassava Peels And Cow Rumen Fluid

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