Andrew Huizenga Lindsay Arnold Diane Esquivel Jeff Christians

Need

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

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

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

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

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

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

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

Final Prototype

Design Decisions

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

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

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

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