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

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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)

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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.

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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

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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

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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.

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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.

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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.

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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.

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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

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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

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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

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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

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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.

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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

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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

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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

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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.

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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.

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Figure 10: Circuit diagram to measure Current and Open circuit voltage (OCV)

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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.

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Figure11: After 48 hours

Figure12: After 72 hours

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Figure 13: Open circuit Voltage after 96 hours

Figure14: Closed circuit Voltage after 96 hours

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Figure15: Current across 100 resistance after 96 hours

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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.

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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

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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.

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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/

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