Bio-electricity Production from Waste using Bacteria in Microbial Fuel Cell

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Posted By : ScienceIndia Administrator

Electricity has now become an essential requirement to sustain our daily life, and we cannot think of a world without electricity. This universal energy resource is commonly obtained through solar power, thermal, hydropower, wind, natural gas, fossil coal, etc. However, have you heard about electricity generation from waste using bacteria? Yes. There is an innovative idea of producing electricity from waste using a device called “microbial fuel cell”.

Waste/wastewater generated through various processes in our day-to-day activities contains organic carbon which acts as a great source of food and energy for bacteria. Waste/wastewater also has an enormous value, which can turn the carbon in it as useful electricity by the action of bacteria. The concept of obtaining electrical energy from bacteria using organic compounds was reported in 1911 by M.C. Potter using a simple electrode setup. Using this idea, experiments were carried out in a microbial fuel cell by combining waste as a source of organic carbon in the presence of bacteria.

A microbial fuel cell (MFC) is a device which transforms the chemical energy stored in waste (organic compounds) into electrical energy in the presence of electrodes and bacteria. MFC can be single chambered or double chambered cell which consists of an anode and cathode. A membrane called “proton exchange membrane (PEM)” will be placed in between anode and cathode to allow the exchange of protons. A simple and well defined mechanism of electron transfer from bacteria to electrodes and bioelectricity production can be illustrated through a double chambered MFC. 

At anode chamber, bacteria utilize waste as carbon and release electrons (e-) and protons (H+) along with some organic products during its metabolism. These electrons will be transferred from bacteria to anode electrode and the protons will be transferred to cathode through proton exchange membrane. At cathode, reduction reactions occur by accepting the electrons and protons from anode. During the transfer of electrons between anode and cathode, a difference in potential is created, which is called the “voltage” or capacity of a cell, and the flow of electrons from one electrode to other is called “current”.

Apart from bioelectricity production, waste or wastewater is also being treated in MFC at anode. As the bacteria utilize carbon, the complex waste is broken down or simplified which will become no more hazardous to environment and the treated water from MFC can be used for non-potable purposes. The energy obtained from MFC is considered eco-friendly due to its clean, green, efficient, and renewable nature. The amount of voltage and current obtained from single MFC can be increased by combining multiple MFCs as stacks which has good scope of increasing bioelectricity production. It can be used for running small electrical devices such as digital clock, small fan, radio battery, LED bulbs, etc.

This can be directly implemented in remote areas which face severe electricity problems. Advances in MFC need to be made which will have a great future in the energy sector and waste treatment in the near future.

Author: J. Annie Modestra, CSIR-Senior Research Fellow, Bioengineering and Environmental Sciences Lab, EEFF Department, CSIR-Indian Institute of Chemical Technology.

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