Type of Soil and Size of a Microbial Fuel Cell on Voltage Production

Abenet AddisuRockdale Magnet School

3/7/12

Introduction

• Family in Ethiopia• Every chemical, pesticide, or

material used contributes to the pollution we have on Earth.

• Using bacteria naturally in soil to create electricity can benefit us in many ways

Rationale

• A successful outcome can help determine future distribution of resources around the world.

Research Purpose

• Determining if we can utilize another source of electricity humans can use in their daily lives.

• To establish a connection between the size of microbial fuel cells and the type of soil used.

Background

• Two Independent Variables – Size of the microbial fuel cell – Type of soil inside the fuel cell• All the soils have three important key

elements in them: phosphorous, nitrogen, and potassium

• Dependent Variable– Voltage produced

Research Hypothesis

• Research sub-hypotheses – Bigger microbial fuel cell will produce

more electricity – High-grade soil with more organic

matter will produce a higher output of electricity.

Experimental Design Diagram

• Independent Variable: Different types of soil and size of microbial fuel cell.

• Hypothesis: The 20 cup microbial fuel cell will produce more electricity and the manure will also produce a higher output of electricity.

• Constants: The anode, cathode, external circuit, the PEM, the copper wire, and the electrodes.

• Dependent Variable: Voltage produced.

20 cup 12 cup (C) 5 cup

Potting Soil 1 1 1

Topsoil (C) 1 1 1

Manure 1 1 1

Garden Soil 1 1 1

Procedure Description

1.Gather two containers2. Drill two holes in one container and one

hole in the other.3. Trace a circle with the compression fitting

in the middle of both containers and cut it out

4. Make the PEM and conductive epoxy according to the directions

5. Glue the PEM in between the two holes of the containers

Procedure Description

6. Glue the copper wire down to the carbon cloth with the conductive epoxy, these will be electrodes

7. Add the conductive saltwater and electrode to the container with two holes, this is the cathode

8. Put the soil and electrode in the other container and this will be the anode

9. Hook the alligator cables to the electrodes and multimeter

10. Record the data

Results

• A significant increase of voltage produced between the 5 cup, 12 cup, and 20 cup microbial fuel cells.

Potting Soil

Topsoil

Manure

Garden Soil

0 0.05 0.1 0.15 0.2 0.25 0.3

The Effect of Type of Soil and Size on Voltage

5 cup12 cup20 cup

Voltage (V)

Type

of S

oil

Conclusions

• The highest voltage came from the control soil, which was topsoil, and the biggest microbial fuel cell.

• Utilized when they are “stacked“ or connected.

Wrap-Up

• Future Research– Expanding independent variables– Different bacteria strains

• Sources of Errors– Inaccurate measurements– The protein exchanging membrane

leaking water

Bibliography

• Liu, H. (2004). Electricity Generation Using an Air-Cathode Single Chamber Microbial Fuel Cell in the Presence and Absence of a Proton Exchange Membrane. Environmental Science and Technology .

• Quick, D. (2010, April 20). Microbial Fuel Cell Generates Electricity From Mud. Retrieved November 8, 2011, from ONR’s: http://www.gizmag.com/onr-microbial-fuel-cell/14863/

• Logan, B. (2008). Microbial Fuel Cells. Hoboken: John Wiley & Sons.