1. Andrew Huizenga Lindsay Arnold Diane Esquivel Jeff Christians

2. Need http://scienceblogs.com/ http://kahdalea.com/

3. Project Objectives  Develop a commercially viable Microbial Fuel Cell (MFC) Sustainable Portable Simple operation Inexpensive

4. Design Norms  Transparency Intuitive Easy maintenance  Stewardship Cost effective Eco-friendly  Cultural Appropriateness Common ingredients

5. Experiments Research Prototypes  Simplified components Agar salt bridge vs. proton exchange membrane (PEM) No pump or filter  Ease of reproducing and testing Easy to dump and refill Multiple experiments Optimization

6. Experiments  Media simplification (substitution/elimination)  Bacterial growth kinetics  Extreme environment resistance  Electrode surface area to chamber volume

7. Experimental Results  Final media Baking soda, vinegar, table salt, phosphate, ammonium chloride in water  Similar results temperatures 18-30 °C  Withstands extreme variation in media  Surface area : volume ≈ 1cm 2 : 1cm 3

8. Design Decisions  MFC Architecture Proton exchange MFC Air cathode Waste water  Bacteria Geobacter metallireducens Geobacter sulfurreducens Rhodoferax ferrifeducens

9. Design Decisions  Electrode Stainless steel Graphite Platinum loaded graphite  Membrane Proton Exchange Membrane (PEM) Salt bridge  Feeding Process Continuous Batch  Semi-Batch

10. Final Prototype

12. Design Decisions

13. Preliminary Results  Voltage 666 mV with 975 kΩ  Power 0.5 μW  MFC in operation since April 15 th

14. Conclusions  Successful prototype Sustainable Portable Simple operation Inexpensive  Technology has potential 22 μW / m 2 of electrode Literature cells produced ≈ 10-20 mW / m 2

15. Project Assessment  Subpar performance due to lack of platinum loaded electrodes  Effectively combined biology and engineering  Developed teamwork skills

16. Acknowledgments  Professor Sykes – Team mentor  Professor Wertz – Biology consultant  Mr. Spoelhof – Industrial consultant  Professor VanAntwerp – Project idea  Ben Johnson – Biology consultant  Membranes International – Donated proton exchange membrane