Microbial Fuel Cell

1. Sedimentary
Based Microbial
Fuel Cells
Evaluated by
Power Density
Zachary Gilstrap
Alston Loper
Matthew Wieters

2. Problem Specifics
To design and implement a sediment based
microbial fuel.
 $20 budget
 Produce 1Watt/m3 of power

3. Definition of Problem
Specifics
(1) C6H12O6 + 6H20  6CO2+24H++24e-
 The oxidation or loss of electrons
(2) 24e- + 24H+  12H2O
 The reduction of gain of electrons
Overall Reaction
C6H12O6 + 6O2  6CO2 + 6H2O
 Aerobic Respiration

4. Definition of Problem
Specifics
V=IR
 Ohm’s Law
P=IV
 Power Equation
Power Density=P/V
 Power Density Equation

5. Goals
Process
 Compatibility with environment
 Aerobic environment for cathode
Structural
 General well being
 Wiring connectivity
 Stability
Mechanical
 Simplistic design

6. Constraints
Equipment
 75% of design from natural or recycled resources
Budget
 $20 limit for the total amount of materials used in design
Skills
 Not particularly efficient engineers
Time
 Two lab periods for fabrication and implementation

7. Considerations
Safety
 Weather
 Tools
Ethical
 Requisitioning resources
 Impact on location population
Environmental
 Cold weather, less prolific bacteria
Life cycle/Use/Sustainability
 Long-term functionality
 Not recommended for professional use
 Sustainable

8. MFC Overview

9. Relevant Designs
• Sediment MFC easily modified
to fit the design goal.
• Mirrored our structural design
off sediment MFC shown with
slight modifications
• Simplistic design required very
little mechanical aspect

10. Relevant Designs
• Larger surface area to
volume ratio was decided to
be beneficial
• Referenced design achieved
3300Watts/m3 using 100mL
anode volume
• Modifying this principle and
aforementioned structural
design, we fabricated our
own MFC

11. Analysis of Design
Simplistic design
 Easily implemented
 Modified for design goal
Larger SA:V principle
 Crushed graphite anode
 Smaller anode volume

12. Synthesis of Design
Crushed graphite had an experimentally observed
density of 0.365g/mL
Anode volume chosen to be 5g or 13.68mL

13. Synthesis of Design
Using this and a simplistic ratio with our second
source and a chosen anode volume of 13.68cm3,
the wattage produced would hypothetically be
.45watts/13.68cm3 for our MFC
 Article design more efficient*

14. Materials and Cost
Materials: Costs
2ft Bamboo N/A
5ft Copper Wire $3.29
10g Crushed Graphite (5g anode & cathode)
$5.38
Window Screen 2.5in x 2.5in (2) $1.76
Electric Tape $0.85
ZipLoc Bag $0.09
Total $11.37

15. Description of Design
 2ft bamboo structural
support
 Crushed graphite
anode and cathode
 Free floating cathode
 Anode buried 3in
within the sediment
 Copper wiring

16. Description of Alternatives
Bamboo could have been replaced with PVC
 Additional cost and environmental impact
Light blue thread could have been replaced with
purple thread
 Stylistic
Potentiometer chosen over bread board
 Potential convenience

17. y = -4138.2x + 0.4518
R² = 0.951
0
0.05
0.1
0.15
0.2
0.25
0.3
4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05 9.00E-05 1.00E-04
Voltage(V)[V]
Current (I) [A]
Polarization Curve
Initial Polarization Curve
Resistance (R)[Ω] Voltage (V) [V] Current (I) [A]
2.8 0.00 0.00E+00
300 0.00 0.00E+00
660 0.06 9.09E-05
2090 0.16 7.66E-05
3650 0.21 5.75E-05
4820 0.24 4.98E-05

18. Initial Power Curve
0.00E+00
2.00E-06
4.00E-06
6.00E-06
8.00E-06
1.00E-05
1.20E-05
1.40E-05
4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05 9.00E-05 1.00E-04
Power(P)[watts]
Current (I) [A]
Initial Power Curve
Resistance (R) [Ω] Voltage (V) [V] Current (I) [A] Power (P) [watts]
2.8 0 0.00E+00 0.00E+00
660 0.06 9.09E-05 5.45E-06
2090 0.16 7.66E-05 1.22E-05
3650 0.21 5.75E-05 1.21E-05
4820 0.24 4.98E-05 1.20E-05

19. Final Polarization Curve
y = -2148.7x + 0.3307
R² = 0.99165
0
0.05
0.1
0.15
0.2
0.25
2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 1.40E-04
Voltage(V)[V]
Current (I) [A]
Final Polarization Curve
Resistance (R) [Ω] Voltage (V) [V] Current (I) [A]
4.2 0 0
635 0.075 1.18E-04
1700 0.145 8.53E-05
2600 0.186 7.15E-05
3800 0.212 5.58E-05
4900 0.226 4.61E-05

20. Final Power Curve
Resistance (R) [Ω] Voltage (V) [V] Current (I) [A] Power (P) [watts]
4.2 0 0 0
635 0.075 1.18E-04 8.86E-06
1700 0.145 8.53E-05 1.24E-05
2600 0.186 7.15E-05 1.33E-05
3800 0.212 5.58E-05 1.18E-05
4900 0.226 4.61E-05 1.04E-05
0.00E+00
2.00E-06
4.00E-06
6.00E-06
8.00E-06
1.00E-05
1.20E-05
1.40E-05
0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 1.40E-04
Power(P)[watts]
Current (I) [A]
Final Power Curve

21. Power Density vs Time
Time [days] Voltage [mV] Power (watts) Voltage (V) [V] Current (I) [A] Power Density [watts/m3]
1 280 1.89E-05 0.28 6.76E-05 1.38
2 320 2.47E-05 0.32 7.73E-05 1.81
3 252 1.53E-05 0.252 6.09E-05 1.12
4 240 1.39E-05 0.24 5.80E-05 1.02
5 210 1.07E-05 0.21 5.07E-05 0.78
6 251 1.52E-05 0.251 6.06E-05 1.11
7 120 3.48E-06 0.12 2.90E-05 0.25
8 314 2.38E-05 0.314 7.58E-05 1.74
9 116 3.25E-06 0.116 2.80E-05 0.24
10 289 2.02E-05 0.289 6.98E-05 1.47
11 220 1.17E-05 0.22 5.31E-05 0.85
Volume [cm3] Volume [m3] Resistance (R) [Ω]
13.68 0.00001368 4140
Constants

22. Conclusions
0.00
0.50
1.00
1.50
2.00
1 2 3 4 5 6 7 8 9 10 11
PowerDensity[watts/m3]
Time [days]
Power Density vs Time
Sediment MFC design successfully achieved an
average power density of 1.07 watts/m3

23. Appendices

24. Appendices

25. Appendices

26. Literature Cited
http://www.nature.com/nrmicro/journal/v4/n7/fig
_tab/nrmicro1442_F3.html
http://www.ncbi.nlm.nih.gov/pubmed/24956566