The world population is estimated to reach 9.5 billion by 2050.
This process can be fuelled using substances called substrates, which include organic materials found in wastewater.
But if the technology is scaled up, it holds great promise.
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MFCs use a system of anodes and cathodes electrodes that pass a current either in or out.
Common MFC systems consist of an anode chamber and a cathode chamber separated by a membrane.
The bacteria grow on the anode and convert the substrates into carbon dioxide, protons, and electrons.
In the cathode chamber, a reaction between the protons and the electrons uses up oxygen and forms water.
And as long as substrates are continually converted, electrons will flow which is what electricity is.
Pee power
Biodegradable matter in waste materials such as feces and urine can be converted into electricity.
Schematic of an MFC latrine.Cynthia Castro et al.
Journal of Water, Sanitation, and Hygiene for Development, 2014.
When plants grow they produce carbohydrates such as glucose, some of which are exuded into the root system.
The microorganisms near the roots convert the carbohydrates into protons, electrons, and carbon dioxide.
By connecting a load into the circuitry, the electricity being generated can be harnessed.
Plant MFCs could revolutionize electricity production in isolated communities that have no access to the grid.
In towns, streets could be lit using trees.
Microbial desalination cells
Another variation of microbial fuel cells aremicrobial desalination cells.
These devices use bacteria to generate electricity, for example from wastewater, while simultaneously desalinating water.
When the bacteria in the anode chamber consume the wastewater, protons are released.
Ions released in the anode and cathode chambers help to improve the efficiency of electricity generation.
Conventional water desalination is currently very energy-intensive and hence costly.
A process that achieves desalination on a large scale while producing (not consuming) electricity would be revolutionary.
Desalination plant in Hamburg.
Current desalination technology is very energy intensive.Andrea Izzotti/Shutterstock
4.
But this process is usually inefficient.
A few start-up companies such asRobialandPlant-eare beginning to commercialize microbial fuel cells.
Its early days, but the technology holds much promise.
