Jeon Yong Won Department of Bioscience and Biotechnology Konkuk University Green Energy & Biosensors Laboratory

1. Energy 6.Terrorism and war 2.Water 7. Disease 3.Food 8. Education 4. Environment 9. Democracy 5. Poverty 10. Population Source Richard Smalley Energy & Nanotechnology Conference Rice University, Houston May 3, 2003

Source IAE 2003

AnodeCathode e-e- e-e- COD CO 2 + H + O 2 + H + H2OH2O = Electrochemically Active MO H+H+ Air H2OH2O CO 2 Wastewater (COD-rich) Effluent (COD-poor)

 Glucose:  C 6 H 12 O H 2 O  6 CO H e -  Acetic Acid:  CH 3 COOH + 2 H 2 O  2 CO H e -  Sulfur:  S H 2 O  SO H e -  Etc.  These electrons are released at a high energy level! Electron production Biological anodes

-Most of the microorganisms are electrochemically inactive. -The electron transfer from microbial cells to the electrode is facilitated by mediators (thionine, methyl viologen, methyl blue, humic acid, neutral red) and so on. -Most of the available mediators are expensive and toxic. -A mediator-less microbial fuel cell does not require a mediator but uses electrochemically active bacteria to transfer electrons to the electrode. Some bacteria, which have nano wire on their external membrane, are able to transfer their electron production via these nano wire. For example, geobacter, shewanella species.

Electrochemically Active Micro-organisms Bio-electrochemistry Source:

Source Nature Reviews 2006 Some scientist found some bacteria can form nanowires after being attached to electrode surface. And electrons also can be transferred through these nanowires.

RVC (Reticulated Vitreous Carbon ) Carbon cloth

In order to measure maximum power output, loadings from 96 to 7600 Ω resistances were applied between the anode and cathode electrode. The voltage and power density were plotted as a function of current. A maximum power density of 8.2 mW/m 2 was obtained at a current of 0.1 mA at 1000 Ω resistance.

After 1 week By varying the circuit resistance, it was determined from a polarization curve that the maximum power density of 20 mW/m 2 at 265 Ω. And after 1 week, increased maximum power density of 90 mW/m 2 at 96 Ω. The reason is many bacteria were attached on electrodes surface successfully.

No wastewater to be disposed after 2012 No wastewater to be disposed after 2012 London Dumping Convention

Once stable voltage generation was observed, polarization tests were conducted by changing the external circuit load in the range of 1 to 35 kΩ. The maximum power density was 56 mW /m 2 at a current of 0.15 mA at 2 kΩ.

The performance of MFC was studied under Both close circuit and open circuit condition duri ng stabilization stage for compare. If MFC performance was test after operating under open c ircuit condition for 2 weeks, the maximum power density was 266 mW/m 2, which was much higher than MFC was stabilized under close circuit condition with constant 2kΩ.

microbialsSubstrateElectrode typeMaximum power density Research group Pseudomonas aeruginosa GlucosePlain graphite88 mW/m 2 Rabaey Escherichia coli LactatePlain graphite91 mW/m 2 Zeicus Activated sludge LactatePlain graphite788 mW/m 2 Zeicus Activated sludge GlucoseWoven graphite 494 mW/m 2 Liu, H Mixed consortium AcetateCarbon paper506 mW/m 2 Liu, H Bacillus subtilis Animal wastewater Carbon cloth266 mW/m 2 Present work

Initial COD of animal wastewater was 5500mg/l. both the systems ( open circuit and close cir cuit ) showed there potential COD removal. We can see in this picture COD level decreased a s function as time. But the relatively higher COD remove efficiency was documented with clos e circuit mode.

 Microbial fuel cells can generate electricity while simultaneously treating the animal wastewater.  A higher power density in close circuit reactor wa s achieved than in open circuit reactor.  COD removal efficiency was higher under close c ircuit than under open circuit.  The maximum power density of 266 mW/m 2 was observed at 2kΩ.

 Powering Monitoring Devices in Remote Locations  Powering Electronic Devices from Renewable Energy Sources  Decentralized domestic power source  Conversion of waste organic matter to electricity  Conversion of renewable biomass to electricity  Bioremediation of environmental contaminants

 Is to maximize power density along with easiest way of wastewater treatment  make the microbial fuel cell using anaerobic reactor

 Prof. Kim, Sunghyun.  Dr. Park, Wonchoul.  Yuan Yong, Jalal Ahmed.  Dr. Park, Chi Ho from National Institute of Animal Science.  BK 21 program.  Korea Research Foundation.