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The English expression “taking the piss (or pee)” has taken on new meaning as far as UK-based scientists are concerned.

But while this colloquial term is an impolite way of indicating someone is making fun of you, researchers at the Bristol BioEnergy Centre of the Bristol Robotics Laboratory – a collaborative venture between the University of West England (UWE Bristol) and Bristol University – are taking urine seriously and have develop a novel way of charging mobile phones using the smelly substance.

Dr Ioannis Ieropoulos, a professor at UWE Bristol, is the principal investigator of what is known as the “urine-tricity” project, funded by the Bill & Melinda Gates Foundation and the UK Engineering and Physical Sciences Research Council (UK EPSRC).

When the discovery was announced last year Dr Ieropoulos said: “We are very excited as this is a world first. No one has harnessed power from urine to do this, so it’s an exciting discovery. Using the ultimate waste product as a source of power to produce electricity is about as eco as it gets.”

The Connected Business asked Dr Ieropoulos about his discovery and how it might be used in the future.

CB: How did the idea for recharging electrical devices using urine come about?

Dr Ieropoulos: As a research group, we have been working with this same fuel cell technology for 12 years, feeding it with different “fuels” and putting it to the test by powering electronic devices. The types of fuel we have been experimenting with are different kinds of organic waste such as domestic waste water, rotten fruits, prawn shells, dead insects and grass clippings.

Urine was just another candidate “fuel”. However, the level of power output improvement was so good that we were able to charge a commercial battery [of a mobile phone] directly, for the first time.

CB: Does the fuel cell have a special name and how does it work?

Dr Ieropoulos: The technology is known as the Microbial Fuel Cell (MFC) and works on bacterial metabolism. Effectively, live microbes, which we collect from the natural environment, inhabit the inside of these devices and break down the organic fuel for their growth and maintenance, which is exactly what they do in nature.

One byproduct of the bacterial respiration comes in the form of electrons, which are transferred on to the electrode surface inside the MFC. These electrons flow through a circuit, which produces the electrical current.

CB: As the Gates Foundation has supported the project, can we expect to see it mainly being applied to developing-world problems, where mains electricity is hard to find?

Dr Ieropoulos: This is the ultimate goal for the work carried out under the Bill & Melinda Gates Foundation grant, and not only as a means of electricity generation but also as a technology that can improve sanitation. But in addition, the work carried out under the UK EPSRC grant is primarily focused at developing this technology for the developed world.

CB: Do you know how Bill and Melinda Gates feel about your project?

Dr Ieropoulos: We do indeed, and this is through Dr Carl Hensman, our programme officer from the water, sanitation and hygiene programme. The co-chairs and trustees, Bill and Melinda Gates, are kept regularly informed and feel excited about our project, as they do for all the projects funded under the different programmes of the Gates Foundation.

CB: How might it be applied in the developed world?

Dr Ieropoulos: We consider the MFC to be a platform technology [something that enables products and processes to be developed from it], with numerous applications in different sectors of society.

The electricity is generated because the constituent microbes break down – and therefore treat – the organic waste, hence one area of focus is waste water treatment.

As the energy generated can be used for powering or recharging electronic devices, low-power electronics is another area of application. Biosensing is a third. This is exploiting the immediate response of the micro organisms to the presence of different compounds.

More recently, it has been demonstrated that MFCs can synthesise chemical compounds, while generating electricity. This means that elemental recovery [turning waste products into useful resources again] is an area that is beginning to grow. So, there are several avenues that can be explored in order to implement the technology in the developed world.

CB: Do you see this as a “disruptive” technology? Could it be an idea that will change the way people produce batteries for torches, say, or make domestic electrical appliances?

Dr Ieropoulos: At community level with waste water treatment, we do not necessarily see the MFCs as a disruptive technology at present, but rather as a complementary solution that can be part of a hybrid system. There is still some way to go before it can replace an existing technology such as batteries, but the EcoBot work we have been developing over the years has shown that small robots can be powered directly by MFCs, without any other form of power supply onboard. This is part of our self-sustainable systems work.

CB: Is it satisfying to see what from the outside seems a completely outlandish idea bear fruit?

Dr Ieropoulos: It is exciting, and this is the very essence of scientific research. To think about the difficult or even impossible and push the boundaries of current knowledge to see if it can work.

CB: How would you like to see this development being used in 10 years' time? Does it have applications for helping counter global warming, for instance?

Dr Ieropoulos: In this timeframe, we would definitely like to see the technology deployed at different scales, in both the developing and developed worlds. There are so many sectors that MFCs can contribute to, either by cutting down energy consumption, increasing the efficiency of waste utilisation or even assisting in the recovery of useful nutrients from organic matter.

This is a technology that turns waste into useful commodities and it would be extremely beneficial to integrate it in existing processes, as it can help cut global warming.

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