We've become a nation of coffee drinkers. Every high street across the country is now
littered with familiar brands selling our favourite hot drink. And whether we drink takeaways
or make our own, what we might not realise is that our Latte or Mocha is generating huge
amounts of coffee waste.
Now researchers at the University of Surrey have turned polluting coffee waste into electricity.
Dr Claudia Avignone-Rossa and his team have discovered that the community of microbes
found in a wastewater treatment plant could hold the key to degrading coffee waste which
is highly damaging to the environment. The microbes eat the waste, producing energy which
can be captured as a small electric current, enough to light a bulb. This type of device,
called a microbial fuel cell, has not been used to treat coffee waste before and marks
an exciting development.
We are really excited because what we found is that in nine months we were able to set
up a system, a working system, with coffee waste and we also were able to set up very
low-cost device using domestic material, household materials. And that was very exciting because
we didn't expect that to be successful so quickly.
Waste from coffee production is a huge global problem and is a particular issue in developing
countries where the infrastructure doesn't always exist to process the waste and so it
ends up in water courses which become contaminated.
In coffee there are two types of waste. One is called the white coming from the primary
processing of the coffee which is done in the farms and that is a solid material with
a lot of flesh from the fruits that contain a very large amount of organic matter which
is highly pollutant and the system normally is not prepared to dispose of the waste in
a proper manner. The other type of waste is that producing in the coffee industry, production
of instant coffee, and instant coffee generates large amount of ground coffee, the same coffee
within the coffee shops, but is in industrial amounts, so that also contains a very large
content of organic matter.
Simple microbial fuel cells can be built for only a few pounds or even pennies using household
materials meaning they're low cost and easy to construct. It could also help to relieve
a huge strain on water supplies as coffee production requires vast quantities of water.
The device that Dr Avignone-Rossa and his team have developed proves it's possible.
The next step is to scale the device up.
I think the next step is to set up a system, a working system in a farm just to prove that
we can scale this from this lab to a real place in the field. That will create a system
that can be deported to other places, not only in one particular farm in one particular
country, but there are a very large number of country producing coffee that would be
a benefit with this type of devices or systems. So yeah we expect that this can expand to
other places. I didn't expect it to be so attractive to people possibly because of coffee,
the coffee effect is important, something that most people drink every day so is something
that you never think what's behind the production of coffee. We take it for granted but at the
moment people are possibly realising that well there is an extreme environmental effect
of coffee and coffee production.
There's already been a great deal of interest in the concept and the researchers hope that
if their device is used successfully in places like Columbia, they may be able to interest
large coffee companies in Europe where roughly one third of the world's coffee is currently
consumed.