Thames water purification on the run
By Julien on Tuesday, April 13 2010, 20:35 - ThamesSourceQuest - Permalink
As previously mentioned, one of the only source of water during the Thames Source Quest (TSQ) might be to drink from the Thames itself.
Ebullition would be the most radical method, but is not practical whilst running. Most commercially available portable water purification systems are based on microfiltration, which performs well against "big bugs" (protozoa and bacteria), but fails against viruses. I would need to use ultraviolet or chemical treatment to get rid of these nasty guys, most likely iodine. Remains the chemical pollution that might be solved partly with an activated carbon filter. I've contacted Thames Water to get more information on the exact nature and distribution of the pollution, but they tend to be very vague, only providing qualitative appreciations such as "bad", "good", "very good". If you have access to more accurate data, please let me know.
Here is my current plan for filtering:
As for the microfilter, I'm considering either the Katadyn Mini (18x8cm, 210g) or the Katadyn MyBottle (26x8cm, 260g). The latter is more practical and includes an activated carbon filter and iodine resin. But this all-in-one design is not suitable for turbid water, which might be the case of the Thames.
I've discovered much more recently the Lifesaver Bottle (30x9cm, 635g), which is claimed to filter at 15 nanometres (0.015 microns)! It would therefore remove all the viruses as well as the bacteria. Plus it's meant to work with muddy water. During one of his talks, the inventor actually filters Thames water (or so he says), with a few much more disgusting add-ons and drinks it. Convincing enough! The main drawback: it's three times as heavy as the Katadyn products.
One funny thing with most websites advertising portable filtering, is that all the "action" pictures seem to involve crystal-clear mountain lakes or springs from which I would drink straight away anyway...
Any comments?
Ultra purification.
(1) Strictly speaking a simple water filter is sufficient.
Ebullition would be the most radical method, but is not practical whilst running. Most commercially available portable water purification systems are based on microfiltration, which performs well against "big bugs" (protozoa and bacteria), but fails against viruses. I would need to use ultraviolet or chemical treatment to get rid of these nasty guys, most likely iodine. Remains the chemical pollution that might be solved partly with an activated carbon filter. I've contacted Thames Water to get more information on the exact nature and distribution of the pollution, but they tend to be very vague, only providing qualitative appreciations such as "bad", "good", "very good". If you have access to more accurate data, please let me know.
Here is my current plan for filtering:
| Pollutant | Example | Size (microns) | Solution |
| protozoa | Giardia | >5 | microfiltering(1) |
| bacteria | E. Coli, Salmonella | 0.2-0.5 | microfiltering |
| viruses | Hepatitis A | 0.01 to 0.3 | iodine (or UV) |
| chemical | DDT, heavy metals | - | activated carbon |
| bad taste | silt iodine | - | activated carbon vitamin C |
As for the microfilter, I'm considering either the Katadyn Mini (18x8cm, 210g) or the Katadyn MyBottle (26x8cm, 260g). The latter is more practical and includes an activated carbon filter and iodine resin. But this all-in-one design is not suitable for turbid water, which might be the case of the Thames.
I've discovered much more recently the Lifesaver Bottle (30x9cm, 635g), which is claimed to filter at 15 nanometres (0.015 microns)! It would therefore remove all the viruses as well as the bacteria. Plus it's meant to work with muddy water. During one of his talks, the inventor actually filters Thames water (or so he says), with a few much more disgusting add-ons and drinks it. Convincing enough! The main drawback: it's three times as heavy as the Katadyn products.
One funny thing with most websites advertising portable filtering, is that all the "action" pictures seem to involve crystal-clear mountain lakes or springs from which I would drink straight away anyway...
Any comments?
Ultra purification.
(1) Strictly speaking a simple water filter is sufficient.
Comments
I don't even want to think about having diarrhoea while running... Have you tried to map the shops opened 24h on the way, see if you can get away with it? Or is being fully self-sufficient part of the challenge?
Filtration at 15 nm... doesn't it take too long with turbid water (even with pressure)? I don't think that you can filtrate litres of water with the same filter, it should get clogged.
@Fred: There won't be many shops at all towards the end, let alone open 24/7. And yes, it's part of the challenge :)
@Yannick: As with most microfiltering systems, there is a cleanable pre-filter ahead of the smallest 15nm pores.
Where will you find water to clean the pre-filter? ;)
Well, from the other end of the filter obviously :D . Sounds a bit like a chicken-and-egg problem, but it should actually be OK if I clean it early enough, before it's completely clogged.
There are fresh water taps at some of the locks, which we used when we ran it, Environment Agency might be forthcoming.