Transcript 원용 - Konkuk
Green Energy & Biosensors Laboratory ELECTRICITY GENERATION FROM ANIMAL WASTEWATER TREATMENT IN MICROBIAL FUEL CELLS Jeon Yong Won Department of Bioscience and Biotechnology Konkuk University Humanity’s top ten problems for next 50 years 1.Energy 2.Water 3.Food 6.Terrorism and war 7. Disease 8. Education 4.Environment 5. Poverty 9. Democracy 10. Population Source Richard Smalley Energy & Nanotechnology Conference Rice University, Houston May 3, 2003 MAIN RENEWABLE BIO-ENERGY Source IAE 2003 MICROBIAL FUEL CELL CO2 e- H2O H2 O CO2 + H+ Effluent (COD-poor) e- Wastewater (COD-rich) O 2 + H+ COD Cathode Anode H+ Air = Electrochemically Active MO Biological anodes Electron production Glucose: Acetic Acid: C6H12O6 + 6 H2O 6 CO2 + 24 H+ + 24 e- CH3COOH + 2 H2O 2 CO2 + 8 H+ + 8 e- Sulfur: S0 + 4 H2O SO42- + + 8 H+ + 6 e- Etc. These electrons are released at a high energy level! Two Types of Microbial Fuel Cells -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. Bio-electrochemistry Electrochemically Active Micro-organisms Source: http://www.geobacter.org NANO WIRES 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. ANODE MATERIAL RVC (Reticulated Vitreous Carbon ) Carbon cloth Development of mediator-less micorbial fuel cell using shewanella putrefaciens Voltage Power density 0.25 8 0.15 6 0.10 4 2 Power density (mW/m ) Voltage (V) 0.20 0.05 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 2 0.20 Current (mA) 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/m2 was obtained at a current of 0.1 mA at 1000 Ω resistance. Effect of NB agar media coated RVC electrode on energy output Voltage Power density Voltage Power density 100 0.25 0.28 20 0.26 18 Voltage (V) 12 0.10 10 After 1 week 0.22 60 0.20 0.18 0.16 40 0.14 2 0.12 2 8 0.05 Power density (mW/m ) 14 0.15 Power density (mW/m ) 16 80 0.24 Voltage (V) 0.20 20 0.10 6 0.08 0.00 0.05 0.10 0.15 0.20 0.25 Current (mA) 0.30 0.35 0.40 0 0.45 0.0 0.2 0.4 0.6 0.8 1.0 Current (mA) By varying the circuit resistance, it was determined from a polarization curve that the maximum power density of 20 mW/m2 at 265 Ω. And after 1 week, increased maximum power density of 90 mW/m2 at 96 Ω. The reason is many bacteria were attached on electrodes surface successfully. ANONYMOUS ANIMAL WASTE DISPOSAL No wastewater to be disposed after 2012 London Dumping Convention ANIMAL WASTEWATER TREATMENT SYSTEM Bacillus subtilis immobilized electrode as carbon cloth anode in microbial fuel cell Voltage Power density 700 60 600 50 Voltage (mV) 40 400 30 300 2 Power density (mW/m ) 500 20 200 10 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 Current (mA) 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 /m2 at a current of 0.15 mA at 2 kΩ. Discharge curve at 2kΩ Voltage Power density 0.636 266 Voltage (V) 264 0.632 262 0.630 2 260 Power density (mW/m ) 0.634 0.628 0.626 -2000 258 0 2000 4000 6000 8000 10000 12000 14000 16000 Time (sec) 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/m2, which was much higher than MFC was stabilized under close circuit condition with constant 2kΩ. Comparative results of MFCs power density microbials Electrode type Maximum power density Research group Pseudomonas Glucose aeruginosa Plain graphite 88 mW/m2 Rabaey Escherichia coli Lactate Plain graphite 91 mW/m2 Zeicus Activated sludge Lactate Plain graphite 788 mW/m2 Zeicus Activated sludge Glucose Woven graphite 494 mW/m2 Liu, H Mixed consortium Acetate Carbon paper 506 mW/m2 Liu, H Carbon cloth 266 mW/m2 Present work Bacillus subtilis Substrate Animal wastewater Variation of COD Close circuit Open circuit 6000 5500 5000 COD (mg/l) 4500 4000 3500 3000 2500 2000 -2 0 2 4 6 8 10 12 14 Time (day) 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. CONCLUSION 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/m2 was observed at 2kΩ. Potential applications of microbial fuel cells 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 FURTHER EXPERIMENT Is to maximize power density along with easiest way of wastewater treatment make the microbial fuel cell using anaerobic reactor ACKNOWLEDGMENTS 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.