Urine could be the answer to cheaper electricity

Nov 01, 2011

(PhysOrg.com) -- Urine can be an abundant fuel for electricity generation, according to British scientists in the first study of its kind.

Researchers from the University of the West of England, Bristol, have described a way of directly producing electricity from using (MFCs).

Their research is published in the latest journal, Physical Chemistry Chemical Physics.

The aims of the team included investigating whether untreated urine can produce electricity through MFCs and to calculate the energy yield from urine when utilised in MFCs. An estimated 6.4 trillion litres of urine is produced every year leaving the researchers to call urine a potential that has so far been neglected.

Three MFCs made from acrylic with 25ml anode and cathode chambers were used in the experiments. Anode and cathode were connected via small pumps to 1l reservoir bottles. Neat (unprocessed) urine was added either as large volumes, ranging between 25ml to 300ml, into the re-circulation reservoir bottle, or by small volumes, 0.1ml to 10ml, as injections directly into the anode inlets. Urine was used fresh or within one week from donation and the samples, between 400-500ml per donation, were taken from a single healthy volunteer on a normal diet with no history of urinary tract or renal disease.

Prior to an injection of 25ml of urine, the MFC was producing 0.9 milliampere per metre squared (mA/m²), which increased to 2.9 mA/m² after one hour from the point of injection.

This amount of urine was sufficient for continuous energy generation over three days, at which point the performance began to plateau and returned to the power output level that the MFC was producing prior to the injection.

The scientists showed that an addition of 25ml of fresh urine took three days to be utilised in a single 25ml volume MFC. For a stack of 10 MFCs, the same sample would require eight hours to be utilised. Based on a daily urine production of 2.5l per person, it would require approximately 300 MFCs to utilise the daily production of an average human being.

The team at Bristol has been running these experiments over two years and say the response to the addition of fresh urine has been consistent throughout. For the single MFCs used in this study, the efficiency of conversion was shown to have an inverse relationship to the amount of urine added as fuel. For volumes up to 25ml of added urine, the efficiency of direct conversion to electricity was between 60 to 70 per cent, whereas for volumes of more than 700ml, efficiency ranged between 22 to 30 per cent.

Lead researcher Ioannis Ieropoulos said: "With an annual global production rate of trillions of litres, this is a technology that could help change the world. The impact from this could be enormous, not only for the wastewater treatment industry, but also for people as a paradigm shift in the way of thinking about waste."

Explore further: Researchers break nano barrier to engineer the first protein microfiber

More information: Urine utilisation by Microbial Fuel Cells; energy fuel for the future, Ioannis Ieropoulos, John Greenman and Chris Melhuish
Phys. Chem. Chem. Phys., 2011. DOI:10.1039/C1CP23213D

Quick facts:

-- 6.4 trillion litres of annual urine production is based on a world population of 6.97 billion and average daily urine production of 2.5l per adult human

-- mA/m² is the international unit of electric current density

Provided by Royal Society of Chemistry

4.3 /5 (16 votes)

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User comments : 23

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ShotmanMaslo
2.3 / 5 (3) Nov 01, 2011
average daily urine production of 2.5l per adult human


But average daily urine is around 1.5l per adult human..
Isaacsname
5 / 5 (3) Nov 01, 2011
Bars will be in luck..

..OT: Something about the new Physorg pagelayout is freezing my PC. Iow, it sucks.
Cynical1
4.8 / 5 (4) Nov 01, 2011
Actually, beer producers will be the best rewarded...
kaasinees
1 / 5 (2) Nov 01, 2011
Article forgot to mention what waste this process produces. It must be transformed into something.
Vendicar_Decarian
1.2 / 5 (45) Nov 01, 2011
Urine. Is there anything it can't do?
Objectivist
5 / 5 (1) Nov 01, 2011
Getting paid to use the public restroom? What a weird turn of events.
Eikka
4 / 5 (4) Nov 01, 2011
The system works on urea, so the question is really how much urea you get, and how much energy it carries.

A single person isn't going to produce very much. 10-20 grams a day. With that amount, and some back of the envelope math I would estimate a single person's pissings would give you something on the order of tens of watt-hours a day. Approximately enough to recharge a laptop if the system isn't too inefficient.

Meanwhile, each person consumes multiple kilowatt-hours per day in lighting, heating and transportation, and food production. For an energy source, it is quite bottom-of-the-barrel.
PPihkala
1 / 5 (1) Nov 01, 2011
So what is the efficiency in terms of $/Wh? I think the residue can be dumped into toilet, like urine is currently. But without knowing the price of Wh, there will be no adopters. Besides, Ni and H utilized in Rossi's E-CAT will be much cheaper energy source.
GenesisNemesis
not rated yet Nov 01, 2011
What about feces?
bredmond
not rated yet Nov 01, 2011
The system works on urea, so the question is really how much urea you get, and how much energy it carries.

A single person isn't going to produce very much. 10-20 grams a day. With that amount, and some back of the envelope math I would estimate a single person's pissings would give you something on the order of tens of watt-hours a day. Approximately enough to recharge a laptop if the system isn't too inefficient.

Meanwhile, each person consumes multiple kilowatt-hours per day in lighting, heating and transportation, and food production. For an energy source, it is quite bottom-of-the-barrel.


if other technologies were more efficient and if this were combined with other energy generating technologies such as processing feces, it might all add up to a viable unit for some households to live off-the-grid.
Vendicar_Decarian
0.8 / 5 (40) Nov 01, 2011
"What about feces?" - GenesisNemesis

Here is the latest poop on feces.

http://www.5min.c...7100818"

Deesky
5 / 5 (1) Nov 01, 2011
They must be taking the piss! :)
scidog
5 / 5 (1) Nov 02, 2011
save it for making gun powder for the water wars...
Fedot
5 / 5 (2) Nov 02, 2011
"British scientists" is now well established trademark.
FMA
1 / 5 (1) Nov 02, 2011
Is the microbe producing the power or the urea decompose naturally and producing the electric power?

If microbe do all the works then wastewater treatment plants can be modify to have one more function.
paulthebassguy
1 / 5 (5) Nov 02, 2011
Bear Grylls will be happy
antialias_physorg
not rated yet Nov 02, 2011
The mA value alone isn't much help. How much power can be drawn from 1 liter of urine?
rawa1
5 / 5 (1) Nov 02, 2011
We should judge the saving of materials and energy, not just energy when judging the contribution of materials hungry solutions of producing of energy from waste.
Isaacsname
not rated yet Nov 02, 2011
I wonder if you could engineer drinks or food to make the body produce urine that would offer a better return ? Or could it be that different genetics would determine this.

Or maybe something synergistic you could take with meals and drinks, etc.

In another area, this could be a great addition to any operation handling livestock or poultry of any sort in large volume. Imagine how much liquid gold you could get from something like a large dairy operation, or pig farm.
antialias_physorg
not rated yet Nov 02, 2011
I wonder if you could engineer drinks or food to make the body produce urine that would offer a better return ?

Anything that is high in nitrogen would do the trick. But you have to always remember that therer is no such thing as 'free energy'. The body has to manufacture that urea at an energy cost that is always (vastly) higher than what you could potentially get out of it if you were to use it in the way mentioned.

Imagine how much liquid gold you could get from something like a large dairy operation, or pig farm.

It really depends on how much energy you could get out of it. Currently nitrogen runoff from animal farming is a real problem - so even with low return it might be worth it just for the ecological side effect.
nkalanaga
not rated yet Nov 02, 2011
Feces can be used to produce methane, which can be burned for fuel. If nothing else, the combination of urine and feces may be able to power the wastewater treatment plants.
Isaacsname
not rated yet Nov 04, 2011

Good points AP, I guess we should drink more Guiness..

With farms, ...comfrey, by far, lots of nitrogen, very easy to grow, makes good erosion control, etc, etc. It was also used extensively for cattle feed for a long time, at least until the 50's or so, specifically because of it's nitrogen content.

I've spent enough time working on farms/studying horticulture/botany, etc, that I see a real need for an injection of new ideas in the ag sciences. It's an area that is wide open for innovations, especially in regards to retrofitting/modifications of currently used systems on farms, ie: things like open-pit digesters.
dav_i
not rated yet Nov 06, 2011
Just going to go waste some energy...