More than a decade ago, a colleague tells me
that there are microbes that produce electricity.
Being a chemist who became a biotechnologist,
it intrigued me and I wondered how it worked.
Bio-electricity is not something [we hear about] daily,
but we know that there are electric fish.
These electric fish, they hunt other fish by electroshock
to swallow them, to feed themselves.
The objectives and the tools are very clear,
but if we now talk about microbes that produce electricity,
it’s a lot less clear.
And besides, we can not observe them with the naked eye,
we need a microscope.
To better understand why they produce electricity,
we must go back to the beginning of this planet.
This planet was covered by volcanoes
and in the atmosphere, there was no oxygen.
There was only nitrogen, methane, CO2, hydrogen,
and it is thought that these first microbes had an uneasy life.
(Laughter)
So, probably, they [grafted] on the surface of the volcanic stones
which contained oxidized metals,
and they sent electrons on these rocks
to install a kind of breathing.
The electrons that go by,
these are the smallest units in the universe
that carry electricity.
For example, the connected,
there is plenty, really full of electrons, but it does not matter.
You do not have electroshock like that.
But in your body,
there are plenty of electrons, millions
which ensures that you can breathe like these microbes.
These electric microbes were discovered about 40 years ago.
The first was the Shewanella of Oneida Lake near New York.
There’s a second one called Geobacter that does the same thing.
Both are relatively well described,
but there are others, many others in fact,
we discovered them in our laboratories
and they are not described, we do not have time to describe them.
There is so much to do in this area,
we work with what we have
and we are trying to produce electricity.
So, electricity generation, now, with microbes,
I will explain it to you with these microbes:
a red, a blue,
red is negative, blue is positive.
Here on this side, we have these microbes,
those microbes that eat the food that’s in the liquid around.
They digest and there are electrons that are released,
they go through my body,
they arrive here [on] the cathode and there, there is the oxygen of the air.
So, I’m energized, I do not know if we can see it.
(Laughter)
It’s a soft electricity,
therefore, I will not die before the end of this presentation.
Now, a little more scientific, there is an animation.
On the left, we have yellow electrons that are negative,
and in red, [we have] protons that are positive.
These electrons are thrown away from microbes on this electrode.
And an electron that is thrown out, which is suddenly all alone,
it is sad.
(Laughter)
It’s looking for a partner right away,
and probably, it’ll find it in the cathode.
There, there is probably a second electron also negative.
And [even] as a couple, both remain negative.
We can not do anything.
(Laughter)
But do not despair, there are protons that are always positive.
They are positive,
they can be alone, in pairs, or with others, it does not matter.
(Laughter)
So, [they] also move to the right.
And once the electron and the proton are gone,
there is an electric effect.
There, the little wheel turns, like a mill that produces flour.
And at the end of this process [we have] the production of water.
The water you can drink, if you want.
So this pile is highly durable.
This is the only waste that is produced.
Now we go to the laboratory.
And in the laboratory, we examine if everything I tell you is true
and we use these small reactors, future engines of electricity,
and we see that it does not produce a lot of electricity.
We can change the parameters, and we get more, of course,
that’s what we do at home, but there is not a lot of electricity.
It’s 0.5 volt.
And we did some research in electronics a few years ago,
to transform this electricity
in an electricity that would allow you to watch TV at home.
The TV consumes 220 volts, not 0.5.
So, we would need 440 of these reactors online
to have this power.
We can facilitate this task with electronics,
but there are several research groups that are trying to actually do that,
but I am a teacher of a high specialized school.
My mandate is applied research.
Applied, that means, it must be useful.
Soon.
(Laughter)
And we were at one point
where we reflected [to know if we were] on the right project.
Also, our microbe was not too happy with the situation
because we could not value his effort.
And we thought about it and we found a great idea:
we do not transform,
we use what we have to solve the biggest problem in the world
we do not talk about it is the phosphate crisis.
And actually, with this microbe,
we arrive with our microbial fuel cell
to produce a cleaner fertilizer than the law requires.
A nice result, for a scientist, it’s not the everyday,
but for once, that’s good.
(Laughter)
(Applause)
I will now explain what is this problem
and how we solved it.
The problem is that agriculture needs fertilizer.
Without fertilizer, there is no growth of plants,
or growth that is unsatisfactory.
Behind, these plants received a phosphate fertilizer
and those in front, [none].
The difference in growth is huge,
and we see that agriculture really needs fertilizer,
otherwise, it does not work, we do not have enough food.
But where does this phosphate come from?
This phosphate comes from mines in Morocco, the United States and China.
It is transformed into a fertilizer,
we put that in agriculture to produce food,
it goes on at home, we feed,
and on this journey, everywhere, we lose the phosphate in the environment.
Finally, it’s lost in the environment,
completely diluted, we can not get it back like that.
And you have to know that in 50 to 80 years,
we no longer have phosphate in these mines.
And after that, you have to replace it.
But that’s not all, it’s even more serious:
in 2030, it is predicted that there will be a phosphate peak.
The phosphate peak, [it’s like] the peak of oil.
From then on, there will not be enough phosphate on the market,
and if there is not enough phosphate on the market,
we can no longer produce food,
and if there is not enough food,
there is a good chance that the world population will decrease.
To fight this, we think that the treatment plants
can help.
Wastewater treatment plants receive wastewater
kitchens, toilets, businesses,
they are treated with microbes and we obtain sewage sludge.
These sewage sludges also contain phosphate.
But this sludge is polluted with toxic metals.
Huge quantities of sludge are produced.
These little hills, in fact, are huge amounts of sludge,
cities do not know how to get rid of this,
they are burned and then thrown away.
We can not use them because they are polluted.
In fact, it is the richest source of phosphate that will stay one day.
So, we must try to find a solution,
and our solution is to put electrodes
in the treatment plants of sewage treatment plants
to produce this bio-electricity
to immobilize the phosphate that is in sewage sludge.
Our reactor here in the middle is one of the reactors we built,
this small reactor has in the middle a white part.
In this white part,
we put the sludge that is left in the reactor
and on the transparent sides, there is the wastewater,
and there, we produce the electricity we put in the center of this reactor –
[occur] in electrochemical reactions,
there are several, I will not bore you with the details-there –
and a supernatant is obtained which contains the phosphate which has been released.
This supernatant is like an old wine.
And in this liquid, we add a little magnesium, ammonium
and a fertilizer precipitates.
And if we remove this precipitate,
it is found that this fertilizer is purer than what the legislation requires.
It is thought that this concept is useful:
because we have energy in the water that we can use,
we have phosphate in water that we can use,
with our microbes, we transfer this energy into electricity,
at the same time, a fertilizer is produced,
at the same time, pure water is produced.
We are expanding this reactor,
we’re going to the 500 liters for now and then to a demonstrator
and we hope we can apply it everywhere.
Thank you.
(Applause)
”
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