My Undergraduate Research Project on: Design, fabrication & Test run of Bench scale Bioreactor for the production of Biogas, using cow dung.

1. i
DECLARATION
I AKAU GENESIS KABOSHIO solemnly declare that this research work is not a
reproduction of another person’s work, it was completely done by me and the
sources of information are duly acknowledged.
AKAU GENEIS KABOSHIO DATE

2. ii
CERTIFICATION
This is to certify that this final year project was carried out under the supervision
of Dr. A.O.AMEH and meets the requirement governing the award of the degree
of Bachelor of Engineering (Chemical Engineering) of Ahmadu Bello University
Zaria and is approved for the contribution to knowledge and literature.
Dr. A.O .AMEH DATE
(Supervisor)
Dr. I.A.MUHAMMED DABO DATE
(Head of Department)

3. iii
DEDICATION
I dedicate this Final year Research Project, first to God Almighty and also to my
late father Mr. Joseph Akau.

4. iv
ACKNOWLEDGEMENT
My profound gratitude goes to the ALMIGHTY GOD, for the gift of life, His
Love, protection and provision.
I also wish to express my sincere gratitude to my mother Mrs Martha Akau, for
her care, moral and financial support.
Also my special appreciation goes to Dr. A.O Ameh, for his intellectual guide
serving as pillars for this research project, also for his patience and
encouragement throughout this research project. I also specially appreciate Jesse
Gambo Wabba, a student of Biological sciences, who has been of incredible help
to me in guiding me and sourcing of valuable materials, from the beginning of the
research work till date.
Finally, my appreciation goes to the entire members of staff of this department for
one way or another, they contributed to my training. And to all those whose
names are not mentioned here most especially my roommates, who have
contributed to the success of this work, or in one way or another supported and
encouraged me, thank you. God bless you all abundantly. Amen

5. v
ABSTRACT
This research work was aimed at designing, fabricating and testing bio-digester
for the production of biogas using cow dung as the feed. Amongst other bio-
digesters, the floating drum bio-digester was selected, designed and fabricated
using the design specifications with Aluminium sheet as the material for
construction. A test run was carried out using dried and pounded cow dung of
which it was mixed with water in the ratio of 1:10 respectively. The slurry was
prepared using cow dung, rumen content and tap water in different proportions
and was digested for 35days of which rumen content (inoculums) was added, pH
of the mixture was recorded to be 7.2, which is within the required pH range from
literature and also within the mesophilic range. The production of biogas began
on the 38th Day with an initial volume of 4011cm3. The cumulative gas as at the
95th Day was 106,432cm3 (106,432,000mm3= 106.432L). Also, the rate of gas
production was calculated and observed to have changed (decreased) from
2863.8cm3/day (between day 38 and 55) to1273.1 cm3/day (between day 56 and
95), and was combustible, which was tested using a burner.

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TABLE OF CONTENTS
DECLARATION…………………………………………………………………i
CERTIFICATION……………………………………………………………….ii
DEDICATION…………………………………………………………………..iii
ACKNOWLEDGEMENT………………………………………………………iv
ABSTRACT……………………………………………………………………...v
TABLE OF CONTENTS…………………………………………….…….……vi
LIST OF FIGURES……………………………………………………………...x
LIST OF TABLES………………………………………………………………xii
CHAPTER ONE…………………………………………………………………..1
1.0 INTRODUCTION…………………………………………………………….1
1.1 PROBLEM STATEMENT…………………………………………………...2
1.2 AIM AND OBJECTIVES…………………………………………………….3
1.3 JUSTIFICATION…………………………………………………………….3
1.4 SCOPE………………………………………………………………………..4
CHAPTER TWO………………………………………………………………….5
2.0 LITERATURE REVIEW…………………………………………………….5
2.1 ORGANIC WASTE…………………………………………………………..7
2.1.1 Types of Waste……………………………………………………………...7
2.1.2 Impact of Organic Waste……………………………………………………7
2.1.3 Benefits of Compositing…………………………………………………….9
2.1.4 Composition of Cow dung………………………………………………….9
2.2 BIOMAS……………………………………………………………………...9
2.2.1 Types of Biomass………………………………………………………….10

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2.2.2 Using Biomass Energy…………………………………………………….14
2.2.3 Biomass and the Environment……………………………………………..15
2.3 RENEWABLE RESOURCES………………………………………………15
2.3.1 Mainstream forms of Renewable Energy …………………………………18
2.4 NON-RENEWABLE RESOURCES……………………………..…………19
2.5 BIOGAS………………………………………………………………..……20
2.6 ANAEROBIC DIGESTION PROCESS…………………………………….21
2.6.1 Hydrolysis/Liquefaction…………………………………………………..22
2.6.2 Acetogenesis………………………………………………………………22
2.6.3 Methanogenesis…………………………………………………………...23
2.6.4 General process description………………………………………………24
2.6.5 Benefit of Bio-Gas Technology…………………………………………..26
2.7 REVIEW OF BIOGAS REACTOR………………………………………..26
2.8 VARIOUS ANAEROBIC DIGESTION SYSTEMS………………………28
2.9 IMPORTANT OPERATING FACTORS IN ANAEROBIC DIGESTION
PROCESS………………………………………………………………………29
2.10 GAS REQUIREMENT AND STORAGE……………………………….34
2.11 TYPES OF ANAEROBIC DIGESTION SYSTEMS…………………….35
2.11.1 Single Stage Process…………………………………………………….36
2.11.2 Single Stage Low Solids (SSLS) Process……………………………….36
2.11.3 Single- Stage High Solids (SSHS) Process……………………………..38
2.11.4 Multi-Stage Process……………………………………………………..40
2.11.5 Multi-Stage Low Solids Process………………………………………..41
2.11.6 Multi -Stage High-Solids Process………………………………………43
2.12 BATCH REACTOR...…………...………………………………………...44

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2.13 ECONOMICS OF BIOGAS………………………………………………45
2.13.1 Economic. ……………………………………………………………….46
2.13.2 Simple design…………………………………………………………….46
2.13.3 Utilization of local materials. ………………………………………...…46
2.13.4 Durability…………………………………………………………………46
2.13.5 Suitable for the type of inputs…………………………………………...47
2.13.6 Frequency of Using Inputs and Outputs…………………………………47
2.14 SAFETY CONSIDERATION………………………………………...47
CHAPTER THREE……………………………………………………………...49
3.0 MATERIAL AND EQUIPMENT…………………………………………...49
3.1 MATERIALS…………………………………………………………..49
3.1.1 Waste and Water…………………………………………………………..49
3.1.2 Cattle Dung………………………………………….……………………..49
3.1.3 Single Super Phosphate…………………….……………………………...49
3.1.4 Ash………………………….…………………….………………………..49
3.2 EQUIPMENT………………………………………………………………49
3.2.1 Spring Weighing Balance………………………………………………….49
3.2.2 Aluminium Sheet…………………………………………………………..50
3.2.3 Thermometer………………………………………………………………50
3.2.4 Hose………………………………………………………………………..50
3.2.5 Mortar and Pestle…………………………………………………………..50
3.2.6 PH Meter JENWAY model 3150…………………………………………50
CHAPTER FOUR………………………………………………………………52
4.0 METHODOLODY………………………………………………………….52

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4.1 MATERIAL SELECTION………………………………………………….52
4.2 SELECTED BIO-DIGESTER………………………………………………52
4.2.1 Criterion for selecting Floating Drums Digester………………………….52
4.3 DESIGN, FABRICATION AND ASSEMBLY OF THE BIODIGESTER..53
4.4 PREPARATION OF SAMPLES………………………………………...…53
4.5 COST EVALUATION FOR THE DESIGN AND FABRICATION OF
THE BIO-DIGESTER………...…………………………………………………54
4.6 TEST RUN OF THE COW DUNG…………………………………………55
CHAPTER FIVE………………………………………………………………..56
5.0 RESULT AND DISCUSSION OF RESULT………………………………56
5.1 RESULTS FROM THE MATERIAL SELECTION ……………...………56
5.1.1 Cost Evaluation for the Design and Fabrication of the Bio-Digester……..56
5.2 RESULTS FOR THE DESIGN OF THE BIO-DIGESTER………………….57
5.3 RESULTS OF FABRICATION OF THE BIO-DIGESTER……….……….59
5.4 RESULTS FRO M THE TEST RUN OF CO W DUN G IN THE
DIGESTER………………………………………………………………….61
5.4.1 Burning Test…..……………………………………………….…………...64
CHAPTER SIX………………………………………………………………...66
6.0 CONCLUSION……………………………………………………………..66
CHAPTER SEVEN……………………………………………………………..67
7.0 RECOMMENDATIONS…………………………………………………...67
LIST OF REFERENCES……………………………………………………….68
APPENDIX……………………………………………………………………..72

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LIST OF FIGURES
Figure 2.1: The Biogas cycle……………………………………………….…….6
Figure 2.2: Types of Biomass……………………………………………………13
Figure 2.3: Global Renewable Power capacity excluding Hydro-electric power.17
Figure 2.7: Examples of Energy sources………………………………………...19
Figure 2.8: The digesters at Tilburg Plant in The Netherlands………………….21
Figure 2.9: Anaerobic Digestion Diagram…………………………………........24
Figure 2.10: The flow diagram of low solids Anaerobic digestion…………….25
Figure 2.12: The DRANCO reactor (A) and Kompogas Reactor (B)………….38
Figure 2.13The Valorga Digester……………………………………………….39
Figure 2.14: The flow diagram of BTA Process………………………………..42
Figure 2.15:Types of Batch Reactor………………………………..……………44
Figure 3.1 a bio-digester………………………………………………………..50
Figure 3.2 Burner……………………………………………………………….50
Figure 3.3 a pH meter…………………………………………………………..51
Figure 3.4 a Weighing balance………………………………………….……...51
Figure 5.1: AUTOCAD design of the Bio-digester with all layers coupled
together…………………………………………………………………………..58
Figure 5.2a: Layer 1 (Water seal)………………………………………………..60
Figure 5.2b: Layer 2 (Reactor)…………………………………………………..60
Figure 5.2c: Layer 3 (Gas collector)……………………………………………..60
Figure 5.2d: Bio-Digester(Layer 1, Layer 2 and Layer 3 all together)……….....60
Figure 5.3: a bar chart, representing the cumulative volumes of biogas
produced from day 1 to day 95………………………………………………...61

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Figure 5.4: Illustration of no biogas produced during the digestion
period/Retention time………………………………………..…………………..62
Figure 5.5: Rate of biogas production from the 38t h day to the 55t h
day………………………………………………………….…………………....63
Figure 5.6: Rate of biogas production from the 56th day to the 95th day.............64
Figure 5.7a: Blue flame from Biogas……………………………………………64
Figure 5.7 b: match, burner and flame…….…………………………………….64
Figure 5.7c: Flames illustrating burning Test, from the Biogas produced. …....65
Figure 5.7d: Research student in the Laboratory with the Bio-digester….……65

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LIST OF TABLES
Table 2.1: Table showing the composition of Cow dung……………………..9
Table 2.2: Amount of bio-gas generated from animal waste and agriculture
residue animal……………………………………………………………..…20
Table 5.1: shows the design specification and sketches that was used for
the calculation……………………………………………………………….59
Table 5.2: Cost Evaluation for the Design and Fabrication of Bio-Digester....…60