19.1 Introduction

305

Table 19.1

Various designs of MFC and its power densities.

Type of MFC

Fuel

Power density (mW/m²)

Single chamber

Glucose

766

Single chamber

Domestic wastewater

464

Two chamber

Glucose

860

Two chamber

Acetate

480

Up flow

Sucrose

560

Single chamber

Complex substrate

600

Single chamber

Glucose

355.5

Two chamber H type

Acetate

13

Two chamber H type

Glucose

33.4

Two chamber

Glucose

40.3

Single chamber

Sewage sludge

6000

2-Chamber air cathode

MFC

Glucose

283

Two chamber

Marine sediment (acetate)

14

Two chamber

Lactate

52

Two chamber

Ethanol

36

Two chamber H type

Lactose

17.2

required for the treatment process. In conventional wastewater treatment, sludge

activation process is largely utilized. Large quantity of sludge produced during

the MFC process, increases the plant operation cost, maintenance, and initial

establishment process. So, it becomes difficult to operate the wastewater treatment

plant in an effective manner. In addition, the waste sludge contains large amount

of organic matter and energy. Energy can be converted into electricity by using

microorganisms which is a known technique for years. Table 19.1 shows the various

MFC designs and their power densities. The cost-effectiveness and sustainable

environment can be taken from squandering water. Moreover, the energy generated

and converted into electrical power might be used for effluent treatment plant along

with water treatment. MFC is a low power consumption process and can reduce the

expense of water treatment. Finally, MFC is a good and reasonable technology for

reaping energy from organic waste matter compared to other energy harvesters [8].

19.1.1.2

Theory of Microbial Fuel Cell

Basic principle behind the MFC is conversion of organic matters into bio-energy

with the help of microbes present in substrate. It incorporates anode and cath-

ode coupled by an external electrical circuit, divided by a membrane shown in

Figure 19.1. At anode compartment, the substrate is oxidized by microorganism and

produce H⁺ and e⁻ions [9]. The anode compartment is an anaerobic section (i.e.

absence of oxygen) because oxygen should be far from the anode region, and it acts

as electron acceptor. The cathode chamber is an aerobic section (i.e. presence of