
6.4 trillion liters of urine may become viable biofuel - ukdm
http://www.geek.com/articles/geek-cetera/researchers-attempt-to-turn-6-4-trillion-liters-of-urine-into-viable-biofuel-20111110/
======
ars
I can't read the actual paper, so I don't know what the bacteria is eating -
pretty much the only thing in any quantity in urine is urea (and urea is more
valuable as fertilizer).

But I will point out that if you have sugar in your urine that is a severe
health problem called Diabetes mellitus. Mellitus means sweet, specifically
sweet urine which was how Diabetes was originally diagnosed.

~~~
hugh3
Reading the actual paper now. Important bits:

 _The composition of excreted normal human urine, is:4 urea 6–18 g day−1, uric
acid 1.8 g day−1, creatinine 0.5–0.8 g day−1, amino acids 0.12 g day−1 and
peptides 0.5 g day−1. Variable amounts of lactic acid, citric acid, bilirubin
and porphyrins, ketone bodies (aceto-acetic acid; β-hydroxybutyrate; acetone),
and small amounts of hexose (glucose) and pentose (arabinose) sugars may also
be present in normal urine. When considering the bio-available organic content
of excreted urine, compounds such as urea and uric acid are not included,
since they cannot be utilised as carbon-energy (C/E) sources by the microbial
community inside an MFC. In total, the dry weight content of metabolisable
organic substrates, within excreted urine, was estimated to be 0.78
g/human/day.4 Due to the insignificant amount of lipid in urine, this has also
been ignored. Therefore, the mean calorific value of 1 g of carbohydrates,
peptides, proteins or amino-acids (as metabolisable substrates within urine)
has been estimated to be 2.08 kcal_

Which, if I'm reading it correctly, means you can extract 1.62 kCal of energy
per day from your urine (assuming 100% efficiency).

This is not a lot. Even if you collected all the urine from a city of one
million people, it would be roughly 80 kilowatts.

~~~
ars
Thanks for reading it! It would take a lot more than 80 kilowatts to even
collect that much urine, much less actually do anything with it.

This is such a non starter I wonder why they even thought about it for longer
than it took to lookup the composition of urine.

------
tryitnow
It just seems like there wasn't much critical thinking in this article. It
doesn't give us an idea of the real magnitude of the potential energy that
could be produced this way. For example, "6.4 trillion liters" is just a
headline grabber (and an effective one), but if it only produces a trivial
amount of energy, who cares?

It also doesn't mention that there are useful alternatives that may be more
economically worthwhile for waste (see the other comments here).

------
Tloewald
The url craps out on my iPad so... Meh. And what the other poster said ...
It's hard to imagine urine being a better fuel than it is fertilizer.

