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8/7/2019 Bio Electricity Production by Mediator Less MFC (Microbial Fuel
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Research By: S. Venkata Mohan, S. Veer Raghavulu, S. Srikanth and P. N.Sarma*Bioengineering and Environmental Engineering Centre, Indian Institute of Chemical
Technology, Hyderabad 500 007, India
Presented By: Arunjyoti BanikM.Tech (BT) 1st Yr 2nd Sem
8/7/2019 Bio Electricity Production by Mediator Less MFC (Microbial Fuel
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Present statistics
8/7/2019 Bio Electricity Production by Mediator Less MFC (Microbial Fuel
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........ Contd
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Materials Usedy Anaerobic Wastewater further enriched with glucose, 3 g/l; NH4Cl, 0.5
g/l; H2PO4, 0.20 g/l; K2HPO4, 0.20 g/l; MgCl2, 0.25 g/l; CoCl2, 20 mg/l;ZnCl2, 10 mg/l; CuCl2, 10 mg/l; CaCl2, 4 mg/l; MnCl2, 10 mg/l.
y Dual Chambered MFC .
Nafion 117
5cm X 5cm X 1cm
8/7/2019 Bio Electricity Production by Mediator Less MFC (Microbial Fuel
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Schematic diagram of the MFC
Glucose
CO2
AeratedPo4 Buffer
Mechanism of CurrentGeneration
50�
8/7/2019 Bio Electricity Production by Mediator Less MFC (Microbial Fuel
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Operationy
Air was continuously sparged maintaining dissolved oxygen (DO) concentration between4 and 5 mg/l.
y The anaerobic mixed microflora was adapted to aseptic anaerobic microenvironmentafter sampling the inoculum.
y Anolyte (synthetic feed and mixed microflora) was recirculated continuously at a rate 100ml/min using a peristaltic pump in order to provide effective contact between the
substrate and mixed consortia.
y Constant removal of chemical oxygen demand (COD) and voltage output wereconsidered as indicators for satisfactory formation of the biofilm and stable operatingconditions.
y Before changing the feed, the inoculum was allowed to settle down (30 min) andexhausted feed(650 ml) was pumped out under anaerobic conditions.
y The settled mixed inoculum (50 ml by volume) was used for subsequent experiments tosustain microflora.
y Fresh synthetic feed (650 ml) was loaded once the voltage started decreasing. After every feeding event, the anode chamber was sparged with N2 for 2 min to maintain anaerobicmicroenvironment.
8/7/2019 Bio Electricity Production by Mediator Less MFC (Microbial Fuel
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Results:
A steady increase in potential difference
was observed with every additional feed
and this might be attributed to adaptation,
phenomenon and development of biofilm
on the graphite surface of the anode.
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For all methanogenic bacteria (MB) specific pH optimum for growth is near pH 7.0,
while acetogenic bacteria (AB) had lower pH optimum around 6.0.
AB are notably less sensitive to pH variations. This made us choose AB as inoculum.
The designed synthetic feed prior to feeding was adjusted to pH 5.5, which facilitated
growth of AB and at the same time inhibit the functioning of MB.
This susceptible environment created, facilitates the generation of molecular H2.
VF A formation and persistent acidogenic metabolism encountered in the anode
chamber presumably indicated a micro-environment congenial to the proliferation of H2-
producing AB rather than H2
-consuming species.
Contd.....
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OLR: Organic Loading Rate;
SDR: Substrate Degradation Rate; VF A: Volatile Fatty Acid;
+ indicates VF A generation;
- indicates VF A consumption;
OLR = {[COD0 X feed rate]/reactor volume}.
SDR = {[(COD0 ± CODT ) X feed rate]/reactor volume}
8/7/2019 Bio Electricity Production by Mediator Less MFC (Microbial Fuel
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Conclusion This study documented the feasibility of bioelectricity generation showing that the
method is environmentally sound and sustainable as substrate was wastewater .
Experimental data revealed the effectiveness of acidophilic conditions maintained
forpower generation within a short period of adaptation time.
The OLR (1/Voltage);OLR (1/Current);OLR CODR % andOLR SDR; However
the last proportionality is valid in all 4 cycles.
The mixed consortia employed do not require soluble mediators, but can donate
electrons directly to the electrode surface by attachment.
They not only produced power in association with COD reduction, but also
facilitated transfer of electrons to the anode without an exogenous mediator.
COD removal efficiency observed enumerated the functioning of
MFCas alternativewastewater treatment unit in addition to renewable energy generation.
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The Ultimate Conclusions
The dual activity could significantly reduce the cost
associated with the current wastewater treatmentmethods.
This process could be effectively integrated to
wastewater treatment plant,wherein renewable energy could be generated alongwith wastewater treatment.
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References:http://www.microbialfuelcell.org
http://www.scienceinschool.org/Issue14
http://www.ias.ac.in/crrsci/jun252007/1720.pdf
http://www.nature.com/nbt/journal/v21/n10/full/nbt8
67.htmlhttp://pubs.rsc.org/en/Content/ArticleLanding/2006/
CC/b600876c
http://www.rshanthini.com/tmp/CP307/MFCWWTre
atment.pdf http://web.mit.edu/pweigele/www/Towards%20a%20
Personal%20Bioreactor/Readings_files/MFC%20revie w-%20Lovely.pdf
en.wikipedia.org/wiki/Microbial_fuel_cell