Kobus Cilliers | On 18, Aug 2019

Darrell Mann

Microbial fuel-cells (MFC) have been around for over a century now, but they’ve never quite made the grade in terms of practical, commercially viable applications. Which is perhaps odd given the fact that they offer the potential to deliver useful electrical energy from little more than waste. Perhaps the story is on the verge of a serious step-change thanks to our patent of the month this month. Not the first time we’ve given the award to inventors from India, but very definitely a first in terms of Indian inventors based in India. At the SRM University in Tamil Nadu state as it happens. Another sign of the times, maybe. The patent was granted as US10,230,122 on 12 March.

The disclosure is beautifully concise. Here’s what the inventors have to say about the problems associated with the prior-art MFCs:

It is an object of the present disclosure to provide an easy, user friendly and cost effective process for fabrication and scaling up of microbial fuel cells (MFCs) from wastes.

Another object of the present disclosure is to provide a real time power utility based on MFCs.

A further object of the present disclosure is to provide higher power density and current density through MFCs.

One more object of the present disclosure is to provide an efficient device and/or apparatus for recycling and reuse of sewage water.

And here’s what happens when we re-structure those conflicting requirements into a contradiction:

Not only is the disclosure write-up simple and elegant, but so is the solution proposed by the inventors. A classic illustration of elegant solutions possessing all the hallmarks of simplicity. To the point where we might begin to wonder why the world hadn’t thought of the solution before. Here it is:

A microbial fuel cell is described comprising an anode chamber having an anode, the anode chamber filled with a first mixture of a buffer solution, nutrients, and at least one microbial inoculum, a cathode chamber having a cathode, the cathode chamber filled with a second mixture of a catholyte mediator and an electron mediator, the cathode chamber connected to the anode chamber via a salt bridge and the cathode and the anode connected through an external electrical circuit, wherein the anode is sealed to maintain anaerobic condition inside the anode chamber while the cathode chamber is maintained in aerobic condition.

Say hello to Principle 3, Local Quality – two chambers, one anaerobic and one aerobic.

I’m predicting a bright future for this one.