We have run many stories in the past about urine being used as a power source, but this week scientists appear to have made a breakthrough discovery. A research team from Bristol have published the world’s first research paper on work that tests the viability of urine as a potential fuel for Microbial Fuel Cells (MFCs) that directly produce electricity.
Dr. Ioannis Ieropoulos, Professor John Greenman and Professor Chris Melhuish from the Bristol Robotics Lab at the University of the West of England have described how urine could be used as a fuel by the MFCs, and how power could be generated.
These fuel cells are designed consisting of two half-cells – an anode and a cathode – which are separated by an ion selective membrane. Traditionally, bacteria is found on the anode side while chemicals and/or oxygen are in the cathode side. This allows for the reaction which in turn generates power.
Dr. Ioannis Ieropoulos explains: “Urine is chemically rich in substances favourable to the MFCs. Our research found that the output of electricity was consistent and measurable depending on the volume of urine and the timing of the doses. At the moment the output from one MFC is small. Through this study and the related work carried out by our group over the years, we were able to show that by miniaturisation and multiplication of the number of MFCs into a stack and regulating the flow of urine, it may be possible to look at scales of use that have the potential to produce useful levels of power, for example in a domestic or small village setting.”
“A stack consists of a number of MFCs, each just a few millilitres of volume, connected together so that the stream of urine runs through the MFCs and produces power as the microbes inside the MFCs get to work on this abundant fuel, which is rich in (amongst other things) carbohydrates, nitrogen, potassium, phosphorous and other organic compounds that collectively make it very good for the microbial fuel cells.”
What about the environmental impact? After all urine does contain several toxins. Well, that’s the advantage of MFCs. No matter the source of the urine, MFCs effectively ‘clean’ the urine so that it can safely be discharged into the environment, removing the need for conventional treatment by wastewater companies.
“Whilst we recognize the need for a great deal more research in this area, we are very excited by the potential of this work,” added Dr Ieropoulos. “This is the first paper to outline not just the use of urine as a potential fuel for MFCs, but also the fact that urine could be an abundant source for electricity generation.”
Considering that each human produces approximately 2.5 liters of urine a day (that’s around 6.4 trillion liters globally each year), the Bristol team’s research could lead to an inexhaustible power supply. In short, the potential to have urine-powered devices may not just be a wet dream.
Via Click Green
Image courtesy of University of the West of England