Ever stood near a body of wastewater?
I cannot imagine the stink and the filth that accompanies it.
Wastewater stinks partly due to the activity of microscopic organisms – bacteria.
These miniature creatures are anything but docile.
They’re energetic and work time beyond regulation.
Their energetic drive comes courtesy of a process called metabolism.
Metabolism means breakdown of food stuff to provide energy.
It happens each second in our bodies so long as we breathe.
Nevertheless it happens on overdrive mode in some microbes because they don’t utilize oxygen like we do.
That is the realm of anaerobic metabolism.
When oxygen is used, the byproducts are water and carbon dioxide (which is what we breathe out).
But when oxygen is briefly supply, these special bacteria (also called anaerobes) produce a combination of acetic acid and electrons.
Now the flow of electrons equals current which equals energy.
Which is why microorganisms and wastewater are a formidable match.
MICROBIAL FUEL CELLS (MFCs)
So what happens after we seal a container with wastewater and insert a conductor like copper, aluminum or carbon?
These anaerobes attach themselves to those conductors and release electrons from metabolism
But since these are conductors, these electrons are easily carried by them in an external circuit.
If we connect this conductor to a different conductor and expose it to air, current will flow.
That is the microbial fuel cell – a tool that derives power from the motion of bacteria.
See photo below.
But microbial fuel cells don’t just derive power from bacteria, they concurrently ‘clean’ wastewater in the method.
You see the dirt in wastewater we see as a pollutant is food for bacteria.
So if bacteria breakdown this dirt and release energy, over time, the dirt will reduce as more energy is produced.
In fact that is the perfect situation which has not yet turn into reality.
It’s because of a couple of reasons.
First, for reasonable current to be generated, it have to be facilitated by low resistance.
Resistance is blockage of current flow.
By nature, MFCs have a high internal resistance because a really small amount of electrons from metabolic activity are captured.
Secondly, for reasonable current flow, there have to be a mechanism to permit exchange of ions between the 2 chambers.
That is facilitated by a special style of salt bridge.
Nevertheless, still with these challenges, some MFCs have been tested and known to generate barely lower than a volt – which is just not yet economically useful.
Nevertheless, if production of energy might be coupled with removal of pollutants, then commercialization of this technology is possible.
MFCs have been used to remove several pollutants from wastewater reminiscent of toxic heavy metals, agricultural nutrients, antibiotics, pesticides etc.
In other words, what if we view these pollutants as a possible energy source through MFCs?
R&D FOR OPTIMIZATION
But in addition, there may be must optimize a few of its features reminiscent of the conductors (or electrodes) and the salt bridge which might be done through research.
These are areas open for engineers, biologists, chemist’s, physicists to enterprise into.
Tools reminiscent of nanotechnology and material science are key on this regard.
It’s one practical way of solving multiple problems at the identical time:
Managing waste, generating energy and cleansing wastewater.
MFCs is likely to be a technology still under the radar.
Nevertheless, it’s potential lies in its ability to tackle multiple problems at the identical time.
My hunch is it has a vibrant future only provided that a couple of visionaries are willing to take a position their money and time to make it fit for commercialization.
Cover photo credit: CDC via Pexels