CHAPTER 1

INTRODUCTION

1.1 An Overview

This chapter provides a brief review on a research study where the aim of research is to

produce electricity from Palm Oil Mill Effluent (POME) wastewater treatment by using

Microbial Fuel Cells (MFCs). Due to the increasing demand for environmentally clean energy,

alternative energy resources have been created. One of the promising technologies used

nowadays is Microbial Fuel Cells (MFCs). This technology represents a new form of renewable

energy by generating electricity from what would otherwise be considered waste. Electricity is

generated through microbial catalysis at the anode under anaerobic conditions and the reduction

of terminal electron acceptor most likely oxygen at the cathode. Finally, introduction, objective

of project and problem statement is addressed in this chapter.

1.2 Introduction

In future, renewable energy will be a large portion of global energy production and usage.

Strong motivation for these alternative energy resources has been created due to the increasing

demand for environmentally clean energy. New approaches for wastewater treatment which not

only reduce cost but also produce useful side-products have recently received increasing

attention. One of the promising technologies used nowadays is Microbial Fuel Cells (MFCs).

The microbial fuel cell (MFC) technology offers a valuable alternative to energy generation as

well as wastewater treatment. MFCs are devices that convert the chemical energy in the organic

compounds to electrical energy. The microbial fuel cell is a bio-electrochemical system in which

bacteria are used to convert organic material into electricity. The fuel cell is made of four parts:

the anode, the cathode, the proton-exchange membrane (PEM), and the external circuit.

According to Bond et al., (2003), MFC is a device that directly converts chemical energy

to electricity through catalytic activities of microorganism. Electricity has been generated in

MFCs from various organic compounds including carbohydrate, proteins and fatty acids. It has

been known for almost one hundred years that bacteria could generate electricity. Only in the

past few years has this capability become more than a laboratory novelty. Microbial fuel cells

(MFCs) are electrochemical conversion devices, excepting that the power generated is derived

from bacterial metabolism. Microbial fuel cells (MFCs) combine the generation of electricity

with the treatment of wastewater through the metabolic oxidation of organic and inorganic

substrates by bacterial species living within a bio film (Davis, S´eamus and Higson, 2007).

MFCs are especially valuable in that there are many applications of their use help to

reduce pollution and cut water treatment costs in a sustainable and environmentally-friendly

way. With future development, MFCs have the potential to produce hydrogen for fuel cells,

desalinate sea water, and provide sustainable energy sources for remote areas. The Microbial

Fuel Cell, which has historically been used only as a novelty in science fairs, is now a

developing reality with great potential for improvements in cleaning techniques and power-

generating processes (Yue and Lowther, 1986).

This technology can use bacterium already present in wastewater as catalysts to

generating electricity while simultaneously treating wastewater. Although MFCs generate a

lower amount of power than hydrogen fuel cells, a combination of both electricity production

and wastewater treatment could reduce the cost of treating primary effluent wastewater.

However, there are little research has been done on determining the effects of voltage output in

comparison to varying fuel cell components. (Pranab and Deka, 2010).

Although there are many types of MFC reactors and many research teams throughout the

world, all reactors have the same operating principles. Several types of MFCs are developed till

date, the common design single chambered or double chambered. In this study, the treatment

efficiency and electricity generation using double chambered MFC was undertaken and were

operated at identical ambient environmental conditions. All MFCs have a pair of battery-like

terminals: anode and cathode electrodes. The electrodes are connected by an external circuit, and

an electrolyte solution helps conduct the electricity. The difference in voltage between the anode

and cathode, along with the electron flow in the circuit, generates electrical power. In a microbial

fuel cell, the substrate (organic matter or biomass) is oxidized at the anode, producing carbon

dioxide and protons and electrons, which are transferred to the electrode. Compounds such as

glucose, acetate or wastewater are catabolized by microorganisms in this fuel cells and converts

chemical energy to electrical energy by this catalytic reaction. (Pranab and Deka, 2010). The

electrons and the protons produced in the anode end up in the cathode via the external electrical

circuit for electrons and the exchange membrane for protons.

In MFCs, substrate is regarded as one of the most important biological factors affecting

electricity generation. A great variety of substrate can be used in MFCs for electricity production

ranging from pure compounds to complex mixture of organic matter present in wastewater. So

far the only objective of the various treatment processes is to remove pollutants from waste

streams before their save discharge to the environment (Liu et.al, 2009).

According to Logan et al., 2005, 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.

MFCs do not store energy like battery. Instead, the energy is converted from one form to

another and the operation is continued as long as fuel is fed to it. However, MFCs cannot convert

the chemical energy into mechanical energy like internal combustion generators and only can

convert the energy directly to electricity. Besides, its potential to generate electricity, MFC also

can be used to measure the strength of wastewater. Application of MFC for wastewater treatment

could be an alternative to reduce the cost of treatment. This MFCs was performed well for

chemical oxygen demand (COD) and biochemical oxygen demand (BOD) removal that

demonstrating the effectiveness of this device for wastewater treatment with removal efficiency

about 90% (Kim, 2002). It is best used for wastewater treatment in wastewater industry which

increase the efficiency of treatment can thus provide clean energy for people. Some of the

benefits of MFCs include: clean, safe, quiet performance, reduce the sludge production low

emissions and ease to operating. (Pranab and Deka, 2010).

1.3 Problem Statement

Energy has always played an important role in human and economic development and in

society’s well-being. As world population continues to grow, so does the demand for energy.

Modern society uses more and more energy for industry, services, homes and transport. Our

most prevalent sources of energy include petroleum, natural gas, coal and nuclear materials.

However, long term use of these conventional fuels has led to public concerns over resource

depletion, pollution, national security and possible climate change implications.

In order to meet the increasing demand of energy in Malaysia, a major challenge facing

the power industry will be having an effective and sustainable energy policy. Since all the urban

areas and 93% of the rural area in Malaysia have access to electricity (World Employment

Report, 2001), the crucial challenge facing the power sector in Malaysia currently is the issues of

sustainability that is to ensure the security and reliability of energy supply and diversification of

the various energy resources.

This challenge must be met without having adverse effect on the environment to ensure

sustainability. Thus, under the 8th Malaysia Plan (2001-2005), the government of Malaysia had

changed the four-fuel policy to the five-fuel policy with the additional of renewable energy as

the fifth source of fuel in 1999. In a long run, the aim of the policy was to generate 5% of the

country’s electricity from renewable sources by 2005 (Leo-Moggie, 2002). Presently, renewable

energy in Malaysia is still generated in a small-scale basis. However, concerted efforts are

currently undertaken by the government to develop and promote the utilization of renewable

energy sources.

Shortage of energy source is not the only problem that happens in this country.

Contaminated water or water pollution are also one of the biggest problem that our country face.

Wastewater from industrial, agriculture and households always been neglected. Improper

management system will cause the wastewater go directly to the river or into the runoff system

of the area and become the point source of water pollution.

Increased awareness among the public and corporate bodies has envisioned the idea of

managing the environment in a friendlier manner. In line with the concept of sustainable

development proposed by United Nations Environment Programme (UNEP), more focus had

been directed at the possibility of converting waste into value-added products such as generating

renewable energy from domestic wastewater using Microbial Fuel Cell. Microbial fuel cells offer

an economical and advantageous way to reduce waste in our environment. Moreover, MFCs use

the energy produced by the microorganisms. It should be noted that microorganisms reproduce

very quickly. Using this alternative, a sustainable, clean, light, supply of energy could be formed.

1.4 Objective

The objectives of this research study are:

To study the effect of total no. of electrode and the effect of electrode size with

electricity generation.

To study the effect of several parameters such pH, BOD, COD and TSS using

POME wastewater treatment using MFC.

To study the capability of double chamber types of microbial fuel cell in

wastewater treatment.