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NATIONAL INSTITUTE OF TECHNOLOGY, CALICUT
CHU 492 MAJOR PROJECT
Project Report
On
DESIGN AND FABRICATION OF MICROBIAL FUEL CELL TO TREAT
WASTE WATER AND GENERATE ELECTRICITY
NAME ROLL NO.
GARIMA VISHAL B090714CH
HARSHIT KRISHNAKUMAR B090921CH
S. SWARAJ REDDY B090934CH
TANIA DEY B090918CH
YUVAPANDIAN RAMASAMY B080414CH
DEPARTMENT OF CHEMICAL ENGINEERING
NATIONAL INSTITUE OF TECHNOLOGY-CALICUT
CALICUT- 673601
2
CERTIFICATE
This is to certify that
NAME ROLL NO.
GARIMA VISHAL B090714CH
HARSHIT KRISHNAKUMAR B090921CH
S. SWARAJ REDDY B090934CH
TANIA DEY B090918CH
YUVAPANDIAN RAMASAMY B080414CH
Students of National Institute of Technology, Calicut have worked on the project
work titled Design and Fabrication of Microbial Fuel Cell to Treat Waste
Water and Generate Electricity under my supervision. This project work is
carried out at Department of Chemical Engineering, National Institute of
Technology, Calicut.
FACULTY COORDINATOR PROJECT GUIDE
(Dr. SHINY JOSEPH) (Dr.LITY ALEN VARGHESE)
3
ACKNOWLEDGEMENT
We take extreme pleasure in expressing our deep sense of gratitude to our project guide
Dr. Lity Alen Varghese, Associate Professor, NITC. We are greatly indebted for her guidance
and all the required facilities he provided.
We would be grateful forever to Mr.Karthik, Research Scholar, Department of Chemical
Engineering, National Institute of Technology, Calicut for providing us a strong insight into the
preparation of synthetic wastewater, without which this project would have never been possible.
We would like to thank Dr.Madhavan K., Department of Chemistry, CWRDM,
Kozhikode, for providing us opportunity to test the waste water in their labs.
We would like to express our sincere thanks to Mr.Hariharan, Research Scholar,
Department of Chemical Engineering, National Institute of Technology, Calicut for having
provided us with such a wonderful guidance.
We would like to extend our humble gratitude towards Mr.Jayaprakash, Research
Scholar, School of Biotechnology, National Institute of Technology, Calicut, without which the
project would have not been possible.
Special thanks to our colleagues, friends and seniors who have been extremely supportive
throughout the project.
4
Contents
Table of Contents 4
Table of Figures 5
List of Tables 5
Abstract 6
1. Introduction 7
2. Background 8
2.1 History 8
2.2 Microbial Fuel Cell 8
2.3 Types of MFC 9
2.4 Sediment type MFC 11
2.5 Mechanism of Electrogenic activity 12
3. Methodology 13
3.1 Design and description of MFC 13
3.2 Procurement of Materials 14
3.3 Fuel Cell Assembly 15
3.4 Running of the MFC 19
4. Results And Discussion 21
5. Conclusion 25
6. Future work 26
7. References 28
5
Table of Figures
Figure1: Schematic diagram of MFC used for bioelectricity generation 10
Figure2: Model diagram of sediment type MFC used for bioelectricity
generation 11
Figure 3: Schematic diagram of our MFC 13
Figure 4: Graphite Electrode from Rangun Mills, Hyderabad 14
Figure 5: Cutting of electrode into disc by power saw in mechanical
workshop NIT Calicut 15
Figure 6: Mesh surface to hold electrodes 16
Figure 7: Laboratory Chemicals used to prepare synthetic wastewater 17
Figure 8: Sterilisation of Synthetic waste water 18
Figure 9: Final MFC Setup 19
Figure 10: Circuit diagram to measure Current and Open circuit voltage
(OCV) 20
Figure11: After 48 hours 22
Figure12: After 72 hours 22
Figure 13: Open circuit Voltage after 96 hours 23
Figure14: Closed circuit Voltage after 96 hours 23
Figure15: Current across 100 resistance after 96 hours 24
List of tables
Table 1: Components of MFC 10
Table 2: Composition of synthetic brewery waste water 17
Table 3: Operation condition 21
Table 4: Consolidated performance of Bioelectricity generation 21
Table 5: Constituents of synthetic Textile wastewater 26
6
ABSTRACT
Microbial fuel cells (MFCs) are emerging as promising technology for the treatment of
wastewaters. Our objective is to propose, set-up and simulate a novel Waste water treatment
method using the Microbial Fuel Cell (proper design and fabrication) generating electricity in
addition to purifying water. The sediment type MFC was designed for this experiment. The
designed system was evaluated for 5 days. Overall, the MFC technology still faces major
challenges, particularly in terms of chemical oxygen demand (COD) removal efficiency. To
improve the efficiency of the fuel cell, running of the experiment becomes time consuming, thus
using the results obtained in the experiment, simulation will be done to predict the results.
7
1 INTRODUCTION
During the last decade, escalating use of fossil fuels associated with CO2 emissions, and
related environmental issues initiated the search for alternative technologies which generate
energy from renewable resources. With increasing concern about sustainable energy supplies and
waste minimization, biomass gained much attention to tap enormous resource for powering
future generations. Ecological technologies are particularly sought after in the field of
environmental protection and restoration due to their sustainable nature. Compared to
conventional wastewater treatment systems, ecological treatment technologies are having
inherent advantages such as limited or no use of chemicals, no foul odours, easy to operate and
are inexpensive, etc., moreover they are ecologically complex, mechanically simple,
environmental friendly.
Microbial fuel cell (MFC) has gained a great deal of attention in recent years for its
capacity to convert organics to bioelectricity through dark-fermentation. Sediment type microbial
fuel cell is a hybrid ecological electrochemical system used to recover power from the sediment
beds of marine, river and lake or from any organic sediment. These systems utilize the natural
potential gradient between the soboxic sediment and upper oxic water, and the electrons released
by the microbial oxidation of organic matter flow from the anode (in sediment) to the cathode (in
water) through an external circuit. Sediment fuel cells enhance the oxidation of reduced
compounds at the anode, thus bringing about the removal of excessive or unwanted reducing
equivalents from submerged soils/sediments. Keeping the advantages of ecological engineering
system, an attempt was made to harness power by employing sediment type fuel cell assemblies
with simultaneous wastewater treatment. The performance of the MFC was evaluated with dual
electrode assemblies. The studied miniature ecological system facilitates both energy generation
and wastewater treatment with a sustainable perspective.
8
2. BACKGROUND
2.1 History
The idea of using microbial cells in an attempt to produce electricity was first conceived
in the early twentieth century. M. Potter was the first to perform work on the subject in 1911.
Current design concept of an MFC was drawn from the works of Suzuki et al, 1976. In India
research work is carried in institutes like IIT Kharagpur, IICT Hyderabad (BEEC div), CSIR-
CECRI Bangalore. Moreover, researchers are working to optimize electrode materials, types and
combinations of bacteria, and electron transfer in microbial fuel cells.
2.2 Microbial Fuel Cell
Microbial fuel cells (MFCs) are an emerging technology which directly converts
chemical energy stored in organic matter to electricity. The interest in Microbial fuel cells is that
they operate under mild reaction conditions, namely ambient temperature and pressure, and use
inexpensive catalysts, i.e. microorganisms or enzyme. A typical microbial fuel cell consists of
anode and cathode compartments separated by a cation (positively charged ion) specific
membrane. In the anode compartment, fuel is oxidized by microorganisms, generating electrons
and protons. Electrons are transferred to the cathode compartment through an external electric
circuit, while protons are transferred to the cathode compartment through the membrane.
Electrons and protons are consumed in the cathode compartment, combining with oxygen to
form water.
Energy and water supply are two of the biggest challenges facing humanity in the coming
decades. The present efforts to develop strategies for the recovery or efficient usage of resources
are, therefore, highly justified. Groundbreaking technology is needed to allow novel means of
converting and conserving resources. Bio electro chemical Systems (BESs) fit within this strive;
the research at the Advanced Water Management Centre encompasses BESs using whole
microbial cells. The fuel cell which uses microbes to generate electricity is said to be a Microbial
Fuel Cell. In MFCs the catalytic action of the microbes helps in conversion of chemical energy
into electricity. In other words they can also be called as Bio-electrochemical systems (BESs).
Unlike conventional fuels that rely on hydrogen gas as a fuel, MFC can do well with the waste-
based organic fuels.
9
2.3 Types of MFC
There are two types of microbial fuel cell:
a) Mediator microbial fuel cell
b) Mediator-less microbial fuel cells.
A mediator is a chemical that facilitates the electron transfer from microbial cells to the
electrode. Some examples of mediators are thionine, methyl viologen, methyl blue, humic acid,
neutral red and so on.
Mediator-free microbial fuel cells do not require a mediator but uses electrochemically
active bacteria to transfer electrons to the electrode (electrons are carried directly from the
bacterial respiratory enzyme to the electrode). Among the electrochemically active bacteria are
Shewanella putrefaciens, Aeromonas hydrophila and others. Some bacteria, which have pili on
their external membrane, are able to transfer their electron production via these pili. We are
developing the mediator-free MFC.
The performance of MFCs can be affected by a number of factors such as Rate of fuel
oxidation, Electron transfer to the electrode by the microbes, Resistance of the circuit, Proton
transport to the cathode through membrane, Oxygen supply and Reduction in the cathode, Type
of microbe and the ion membrane used, and Temperature maintained.
10
Figure1: Schematic diagram of MFC used for bioelectricity generation
Component of MFC Materials
Anode Graphite, graphite felt, carbon paper,
carbon-cloth, Pt, Pt black, reticulated
vitreous carbon (RVC)
Cathode Graphite, graphite felt, carbon paper,
carbon-cloth, Pt, Pt black, RVC
Proton exchange
Membrane (PEM)(if any)
Proton exchange membrane: Nafion, Ultrex,
polyethylene. poly (styrene-co-
divinylbenzene); salt bridge, porcelain
septum, or solely electrolyte
Electrode catalyst Pt, Pt black, MnO2, Fe3+
, polyaniline,
electron mediator immobilized on anode
Table 1: Components of MFC
11
2.4 Sediment Type MFC
Sediment type microbial fuel cell otherwise called as benthic fuel cell is a hybrid
ecological electrochemical setup/system used to recover power from the sediment beds of
marine, river and lake or from any organic sediment. These systems utilize the natural potential
gradient between the sediment and upper oxic water, and the electrons released by the microbial
oxidation of organic matter flow from the anode (in sediment) to the cathode (in water) through
an external circuit. Sediment fuel cells enhance the oxidation of reduced compounds at the
anode, thus bringing about the removal of excessive or unwanted reducing equivalents from
submerged soils/sediments.
Figure2: Model diagram of sediment type MFC used for bioelectricity generation
12
2.5 Mechanism of Electrogenic Activity
The electrogenic activity of the bacteria takes place by the following steps. At each
electrode, the steps are given below.
At anode (anaerobic):
a) Bacteria converts substrate (organic waste water) to release CO2 protons and electrons
b) Electrons accepted by anode
c) No oxygen condition
At cathode (aerobic):
a) Electron reaches the cathode through the external circuit, thus generating power
b) Hydrogen reaches cathode through the electrolyte
c) Oxygen present at cathode is reduced to water combining with hydrogen and electron.
The equations of the fuel cell at anode and cathode are
Anode:
CH3COO + 4H2O (Biocatalyst) 2HCO3
+ 9H
+ + 8e
Cathode:
2O2 + 8H+ + 8e
4H2 O
13
3 METHODOLOGY
3.1 Design and description of MFC
The MFC used in our project is a single chambered mediator less and membrane less set
up. Performance of MFC was studied in a tank with circular base of 30 cm as diameter and
height 25cm made of plastic with a working volume of 15000cc. Prior to start up tank was filled
with sediment. A combination of synthetic waste water and Milma dairy waste water was used as
wastewater for the experiment. Non catalyzed graphite disc shaped electrodes (diameter 10cm
thickness 1cm, surface area 188.5 cm2) were used as anode and cathode. The anodes (5
electrodes) were placed in the sediment at a depth of 1.0 cm from the sediment at the bottom. All
the cathodes (6 electrodes) were placed on the top sub-surface of the water. Top portion of the
cathodes was exposed to air while the bottom portion was in contact with the wastewater. Copper
wires sealed with epoxy sealant were used for contact with electrodes.
Figure 3: Schematic diagram of our MFC
14
3.2 Procurement of Materials
a) Tank system: A plastic tub of diameter 30cm and height 25cm with an approximate
volume of 15000cc was purchased from local general store shop in Kattangal, NIT
Calicut campus.
b) Electrode: A graphite electrode of cylindrical shape with radius 5cm and height 15cm,
used in the study were furnished by Rangun Mills, Hyderabad.
Figure 4: Graphite Electrode from Rangun Mills, Hyderabad
c) Mesh, Connecting wire, Epoxy sealant, Resistor: All these were purchased in required
amounts from the local hardware shop T.M Store Kattangal, NIT Calicut campus.
d) Waste water: The wastewater sample used was a combination of synthetic wastewater
and Milma Dairy effluent water. Synthetic waste water was prepared in the departmental
laboratory; whereas Milma Dairy effluent water was fetched from the MILMA,
Kozhikode Regional dairy Plant in Peringolam, Kunnamangalam.
15
e) Sediment: The sediment was collected from a river bed from a depth of nearly 2 ft.
present near the NIT Calicut Campus.
3.3 Fuel Cell Assembly
Step 1 (Cutting of electrode and preparation of mesh)
Graphite electrode purchased was sliced in 11 equal discs of thickness 1cm from the
college mechanical workshop. A plastic coated metal mesh was bent to hold the electrodes in
such a way that one surface should be in contact with the surrounding air and the other inside
the water.
Figure 5: Cutting of electrode into disc by power saw in mechanical workshop NIT Calicut
16
Figure 6: Mesh surface to hold electrodes
Step 2 (Preparation of synthetic waste water)
A simulated effluent proposed by Tam et al. (2005), whose composition is shown in
Table 1 was prepared. The synthetic effluent was buffered for the batch experiments to
maintain the pH at approximately 6.5 and during experiments the pH remained within 5% of
the initial value. The buffering agents consisted of salts of sodium phosphate (NaH2PO4) and
sodium phosphate (Na2HPO4). As an inorganic nitrogen source ammonium sulfate
[(NH4)2SO4] was used. As recommended by Tam (2002), some of the culture medium
components were autoclaved separately in order to prevent the precipitation of complexes
formed due to the high temperatures attained during autoclaving. The ammonium sulfate,
peptone and yeast extract were weighed to a screw cap Pyrex bottle, with 1000 mL of
capacity, and filled with 500 mL of distilled water. Dextrose, malt extract, and buffer salts
were weighed to another screw cap Pyrex bottle, with 1000 mL of capacity, and fil1ed with
500 mL of distilled water. Both bottles were then autoclaved at 121oC for 20 min and after
autoclaving the junction of the two components parts was performed under aseptic
17
conditions. The required volume of ethanol was then measured and added to this mixture.
After preparing the synthetic waste water the volume was made up to 10L by adding water to
the mixture.
Compounds Concentration
Malt Extract (g/l) 1.00
Yeast Extract (g/l) 0.5
Peptone (g/l) 0.15
Dextrose (g/l) 0.86
Ethanol (ml/l) 2.00
(NH4)2SO4 (g/l) 2.20
Na2HPO4(g/l) 0.14
Table 2: Composition of synthetic brewery waste water
Figure 7: Laboratory Chemicals used to prepare synthetic wastewater
18
Figure 8: Sterilisation of Synthetic waste water
Step 3 (setting up of tank)
Out of the 11 electrodes, 5 Graphite electrodes (acting as anode) were embedded in the
sediment, and other 6 electrodes were provided as cathode. First, a small amount of sediment
was spread evenly at the bottom of the tank. Then, the anode electrodes were placed in it.
Later, rest of the sediment was poured uniformly into the tank so that it completely covers the
anode (to provide anaerobic conditions). After the anode tank was filled with sediment, 10L
of waste water was added to the tank system. In MFC the sediment layer was considered as
anodic chamber and the anodes were placed in the sediment at a depth of 1.0 cm in the
sediment approximately. All the cathodes were placed on the top sub-surface of the water
using the mesh. Top portion of the cathodes (open-air) was exposed to air while the bottom
portion was in contact with the wastewater. The electrode assemblies represent sediment type
configuration. Copper wires sealed with epoxy sealant (M-seal) were used for contact with
electrodes.
19
Figure 9: Final MFC Setup
3.4 Running of the MFC
The experiment was run for 5 continuous days without any disturbance. After 72 hours of
operation, power generation was tested using multimeter at intervals of 24hours. Readings
for open circuit voltage, current through 100 Resistance and the closed circuit voltage (for
100 resistor) were noted down using multimeter for next two days.
Measurement of Power generation
Open circuit voltage was measured by connecting the cathode of the system to the red
wires of the multimeter, designated as a voltmeter, set at 2000mV. Anode of the system was
then connected to black wire of the voltmeter. Hence obtained display value on the
multimeter was the Open Circuit Voltage. Current reading was taken by connecting the black
wire of ammeter to the one end of the 100 resistor and the other end of the resistor is
connected to the system anode. The second readings were preferred than first readings as
there might be a sudden overflow of electrons in the first readings hence leading to error in
measurement.
20
Figure 10: Circuit diagram to measure Current and Open circuit voltage (OCV)
21
4 RESULTS AND DISCUSSION
The following result was obtained from the experiment when carried for continuous 5 days.
Operation period (Days) 5
COD loading (mg/l) 3635 (approx)
pH 6.85
Table 3: Operation condition
Day 3 Day 4 Day 5
Open circuit voltage 198 202 220
Closed circuit voltage 1.48 1.52 1.68
Maximum current 148 152 168
Table 4: Consolidated performance of Bioelectricity generation
As we can see from the measured voltage values, the voltage and hence the current is
increasing as the number of days increases. But, the MFC takes some time to show measurable
current, that is why we measured the current after 72 hours of setting up the apparatus. After that
initial setup time, voltage has been increasing with time. There was significant bacterial growth
in the tank, which could be observed by the color of the top surface of the tank. This also
reflected in the generation of current by the MFC. After 5 days, the current was slightly
increasing. This is a novel method for generation of current from waste water and will be useful
in any industry or house hold appliances.
22
Figure11: After 48 hours
Figure12: After 72 hours
23
Figure 13: Open circuit Voltage after 96 hours
Figure14: Closed circuit Voltage after 96 hours
24
Figure15: Current across 100 resistance after 96 hours
25
5 CONCLUSION
Any river bed or sediment has anaerobic bacteria at a shallow depth. These bacteria have
the potential to act as electrogenic bacteria. Thus river bed was used for sediment to generate
electrogenic bacteria. Initially, there was no current generated because, the number of
electrogenic bacteria were less. After an anaerobic environment is built up in the MFC, the
electrogenic bacteria started to flourish and thus power generation started to increase. We took
the sample after 3 days and the experiment is still in progress. After 5 days, the current was still
increasing. The sample testing is being done to study parameters like COD, pH, and the
oxidation reduction potential and the results are yet to come from CWRDM.
26
6 FUTURE WORK
Under present investigation, the membrane less MFC was used effectively for synthetic
wastewater treatment and power generation. If power generation in these systems can be
increased, MFC technology may provide a new method to offset wastewater treatment plant
operating cost, making wastewater treatment more affordable for developing and developed
nations.
To make this happen easily and to estimate the power generation without
conducting experiment by using initial properties of waste water, the same procedure of
investigation used for brewery waste water is adopted to produce current using textile waste
water and milk waste water. The composition to be used for preparation of different types of
waste water is
Chemical constituents used for the preparation of synthetic Textile wastewater
Materials used Concentration
(mg/L)
Starch 1000
Acetic acid 200
Sucrose 600
Dyes 200
NaOH 500
H2SO4 300
Na2CO3 500
NaCl 3000
Sodium lauryl sulphate 100
Table 5: Constituents of synthetic Textile wastewater
27
The Milk waste water is collected from MILMA diary, Kunnamangalam for testing and
running the experiment.
Then the parameters like C.O.D, pH, Oxidation/Reduction potential, current produced are
studied in these three experiments conducted.
Then using the studies and the results obtained, a code is written in MATLAB software
using multiple regression analysis to estimate the current production and reduction of C.O.D
using the initial properties of waste water. We will be doing some data preprocessing techniques
that should be applied to a data set to gain insight into the type and nature of data set being used.
Multiple regression is a flexible method of data analysis that may be appropriate whenever a
quantitative variable (the dependent or criterion variable) is to be examined in relationship to any
other factors (expressed as independent or predictor variables). Relationships may be nonlinear,
independent variables may be quantitative or qualitative, and one can examine the effects of a
single variable or multiple variables with or without the effects of other variables taken into
account.
28
7 REFERNCES
[1] Bruce E. Logan, exoelectrogenic BACTERIA THAT POWER MICROBIAL FUEL
CELLS 2009, macmillan publishers limited
[2] Logan B.E, Regan, J.M electricity producing bacterial communities in microbial fuell cell
2006
[3] S. Venkata Mohan *, G. Mohanakrishna, P. Chiranjeevi, Dinakar Peri, P.N. Sarma,
Ecologically engineered system (EES) designed to integrate floating, emergent and
submerged macrophytes for the treatment of domestic sewage and acid rich fermented-
distillery wastewater: Evaluation of long term performance, 2009
[4] http://www.microbialfuelcell.org/www/
[5] http://en.wikipedia.org/wiki/Microbial_fuel_cell
[6] http://www.microbialfuelcell.org/www/index.php/Principles/
[7] www.elsevier.com/locate/biortech
[8] https://illumin.usc.edu/printer/134/microbial-fuel-cells-generating-power-from-waste/
[9] http://www.microbialfuelcell.org/www/index.php/Scalable-reactors/
[10] https://docs.google.com/viewer?a=v&q=cache:DrAk9BkSzDoJ:www.microbialfuelcell.org/P
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4C_bs0pdy94Q&sig=AHIEtbT_5ETBsmhR3ZvEFNneuSmY6q2gaA