View Full Version : Yet another water purifier?
Anyone had any experience of these things: www.lifesaversystems.co.uk ? Could this be a really good way of getting the nasties out of water without boiling, chemicals or UV light? They look pretty good but pricey.
They've been mentioned before on here. Do a search for water purification.
I think the conclusion was a good bit of kit, though big/heavy and the cost is pretty cheap when considering nothing needs to be replaced for 4000l/6000l. Something like 5p/l I seem to remember.
These are on issue to my brothers' unit. He says they are awesome.
Can I ask why UV isn't an easy way of cleaning the water? Is it just that it only kills bugs but doesn't remove chemical impurities?
cheers,
Toddy
and the cost is pretty cheap when considering nothing needs to be replaced for 4000l/6000l
ummm.... thats not quite right .... The cartridge that removes bacteria, viruses, cysts, parasites, fungi and all other microbiological water-borne pathogens only needs to be replaced every 4000/6000l, but the activated charcoal filter that is used to reduce a broad spectrum of chemical residues including pesticides, endocrine disrupting compounds, medical residues and heavy metals such as lead and copper is only designed to last 250 litres.
So... although the cartridge has 'FAILSAFE technology' (ie its harder to pump as it comes to the end of its life) you still need to keep a track on how many litres you have filtered through it (and remember they only hold 750ml of water) so you know when to replace the activated charcoal block.
Ed
Gailainne
11-12-2007, 01:03
Can I ask why UV isn't an easy way of cleaning the water? Is it just that it only kills bugs but doesn't remove chemical impurities?
cheers,
Toddy
Exactly right, UV only kills biologicals, you need a filter of some kind to remove suspended particles, as well as any chemicals, heavy metals. (BTW anything clouding the water reduces the UV effectiveness) and activated charcoal is one of the ways to help remove chemicals and heavy metals, theres resins and reverse osmosis filters too, as always it depends on circumstances, location as to what level (if any) filtration is required to make your water safe. As an aside the Lake at Arjung where we did the Vildmark/WEISS courses we drank straight out of the lake, no filtration required.
Heres a link (http://www.bushcraftuk.com/forum/showthread.php?t=25042&highlight=water+filters) to a recent discussion.
Stephen
I did wonder, thanks for the links.
So, if I'm fairly sure the water isn't polluted 'chemically', a millbank bag or the like and boiling will be fine.
Tbh I've drunk water straight from an awful lot of places here too and never had a problem. I sometimes wonder just how bad our systems actually are?
cheers,
Toddy
last 250 litres.
Ed
Hmm was just remembering what I read on another thread.
Reading the manual, it does indeed state the charcoal filter is only for 250l.
And the UF filter is for 4000l/6000l, which I guess has the failsafe.
nicodiemus
11-12-2007, 08:51
That unit looks like its fantastic for warm climates. Good to know at least some units are getting good kit to play with, eh? With a bit of insulation for arctic climates, the only limitation would be the slightly smaller capacity... most soldiers being used to a litre at least..
Edit: I just noticed something, actually. It's got a membrane filter, which implies its soft. The fact they've put a polymer sheath around it with "gills" to allow water flow says to me that it's delicate. If you're using particularly grimy water, or you're sponging condensate from a rock in the desert or something... will sand / debris damage the membrane?
I guess that's something ceramic filters have up on this one.
As a point of interest the RAF looked at these and rejected them when compared to the Pre Mac MWP as issued in survival packs.
BorderReiver
11-12-2007, 11:46
I did wonder, thanks for the links.
So, if I'm fairly sure the water isn't polluted 'chemically', a millbank bag or the like and boiling will be fine.
Tbh I've drunk water straight from an awful lot of places here too and never had a problem. I sometimes wonder just how bad our systems actually are?
cheers,
Toddy
Aye Toddy,I've drunk water from natural features in my younger days.
I would not want to do it now though,pollutants seem to have got into most water courses even the fairly remote ones.Not just the odd dead deer to worry about these days.:rolleyes:
chem_doc
11-12-2007, 15:19
Exactly right, UV only kills biologicals,...<SNIP>
Stephen
Not quite right. UV light isn't just one wavelength. It's a spectrum, just like visible light.
If you use wavelengths of high enough energy, you can start chewing up all kinds of things, even organic molecules. In fact, that's how it kills bugs in the water. The light messes up proteins in the bug and it dies.
But the efficiency of the UV light on chewing up organics depends upon how well it abosrbs the UV light. Think of it like this: Food coloring abosrbs a whole lot of visible light, that's why it's so birghtly colored. Methanol/meths/stove fuel doesn't absorb much visible light at all, so it looks like water. The same thing goes for other wavelengths of light. Building on the dye example, dyes/construction paper is pretty easily bleached or faded (which is destroying the dyes in it) just from the UV light from the sun.
Off the top of my head, I'm not certain that anything considered to be UV light has enough energy to destroy something like meths.
And in any event, the UV light probably won't take organics all the way down to carbon dioxide and water...
But it does help decompose organics.
However, the energy needed to rapidly/effectively do that is probably a whole lot more than a simple "UV Pen" could contain using standard batteries.
So it becomes more of a "effort/energy/time" thing than UV light not doing anything to organics....
Doc
As a point of interest the RAF looked at these and rejected them when compared to the Pre Mac MWP as issued in survival packs.
Would be interesting to know the reason why.
Not quite right. UV light isn't just one wavelength. It's a spectrum, just like visible light.
If you use wavelengths of high enough energy, you can start chewing up all kinds of things, even organic molecules. In fact, that's how it kills bugs in the water. The light messes up proteins in the bug and it dies.
But the efficiency of the UV light on chewing up organics depends upon how well it abosrbs the UV light. Think of it like this: Food coloring abosrbs a whole lot of visible light, that's why it's so birghtly colored. Methanol/meths/stove fuel doesn't absorb much visible light at all, so it looks like water. The same thing goes for other wavelengths of light. Building on the dye example, dyes/construction paper is pretty easily bleached or faded (which is destroying the dyes in it) just from the UV light from the sun.
Off the top of my head, I'm not certain that anything considered to be UV light has enough energy to destroy something like meths.
And in any event, the UV light probably won't take organics all the way down to carbon dioxide and water...
But it does help decompose organics.
However, the energy needed to rapidly/effectively do that is probably a whole lot more than a simple "UV Pen" could contain using standard batteries.
So it becomes more of a "effort/energy/time" thing than UV light not doing anything to organics....
Doc
Now that makes sense :You_Rock_ I couldn't work out why it seemed so limited when I was sure UV light 'could' affect a wide range of things.
Back to the energy needed then.
cheers,
Toddy
Would be interesting to know the reason why.
Size, cost, results.
Not quite right. UV light isn't just one wavelength. It's a spectrum, just like visible light.
If you use wavelengths of high enough energy, you can start chewing up all kinds of things, even organic molecules. In fact, that's how it kills bugs in the water. The light messes up proteins in the bug and it dies.
But the efficiency of the UV light on chewing up organics depends upon how well it abosrbs the UV light. Think of it like this: Food coloring abosrbs a whole lot of visible light, that's why it's so birghtly colored. Methanol/meths/stove fuel doesn't absorb much visible light at all, so it looks like water. The same thing goes for other wavelengths of light. Building on the dye example, dyes/construction paper is pretty easily bleached or faded (which is destroying the dyes in it) just from the UV light from the sun.
Off the top of my head, I'm not certain that anything considered to be UV light has enough energy to destroy something like meths.
And in any event, the UV light probably won't take organics all the way down to carbon dioxide and water...
But it does help decompose organics.
However, the energy needed to rapidly/effectively do that is probably a whole lot more than a simple "UV Pen" could contain using standard batteries.
So it becomes more of a "effort/energy/time" thing than UV light not doing anything to organics....
Doc
That was a wonderfully clear explanation thanks Doc ;)
I picked this one up yesterday for a fiver
http://www.bushcraftuk.com/forum/showthread.php?p=353914#post35 3914
Gailainne
11-12-2007, 21:04
Not quite right. UV light isn't just one wavelength. It's a spectrum, just like visible light.
If you use wavelengths of high enough energy, you can start chewing up all kinds of things, even organic molecules. In fact, that's how it kills bugs in the water. The light messes up proteins in the bug and it dies.
But the efficiency of the UV light on chewing up organics depends upon how well it abosrbs the UV light. Think of it like this: Food coloring abosrbs a whole lot of visible light, that's why it's so birghtly colored. Methanol/meths/stove fuel doesn't absorb much visible light at all, so it looks like water. The same thing goes for other wavelengths of light. Building on the dye example, dyes/construction paper is pretty easily bleached or faded (which is destroying the dyes in it) just from the UV light from the sun.
Off the top of my head, I'm not certain that anything considered to be UV light has enough energy to destroy something like meths.
And in any event, the UV light probably won't take organics all the way down to carbon dioxide and water...
But it does help decompose organics.
However, the energy needed to rapidly/effectively do that is probably a whole lot more than a simple "UV Pen" could contain using standard batteries.
So it becomes more of a "effort/energy/time" thing than UV light not doing anything to organics....
Doc
So to this end as we are dealing with water purification, we are dealing with UV-C, you are in fact agreeing with me ?
The only camping UV device I'm aware of (I'm sure there are more) is the steripen (http://www.catch22products.co.uk/SteripenMicrobiological-Test.html), battery powered, I wouldnt trust one, to be frank, as I said before they are only effective if the suspended particulates are removed first (mills bag) or any kind of pre filter, there are cheaper more effective filtration systems out there, and ones that dont depend on batteries.
The other thing about UV treated water is it must be used almost immediately, as I believe spores are not effected, and will continue to reproduce even after UV filtration. (Not 100% on that one, my sister (HSE) told me that, havent found any confirmation yet.
Stephen
chem_doc
11-12-2007, 21:09
Now that makes sense :You_Rock_ I couldn't work out why it seemed so limited when I was sure UV light 'could' affect a wide range of things.
Back to the energy needed then.
cheers,
Toddy
I sometimes worry about posting drivel like my previous post. I don't want to come across as a "know it all," just trying to clarify/demistify things....
Doc
chem_doc
11-12-2007, 21:21
So to this end as we are dealing with water purification, we are dealing with UV-C, you are in fact agreeing with me ?
The only camping UV device I'm aware of (I'm sure there are more) is the steripen (http://www.catch22products.co.uk/SteripenMicrobiological-Test.html), battery powered, I wouldnt trust one, to be frank, as I said before they are only effective if the suspended particulates are removed first (mills bag) or any kind of pre filter, there are cheaper more effective filtration systems out there, and ones that dont depend on batteries.
The other thing about UV treated water is it must be used almost immediately, as I believe spores are not effected, and will continue to reproduce even after UV filtration. (Not 100% on that one, my sister (HSE) told me that, havent found any confirmation yet.
Stephen
Yep, any portable UV light source probably isn't going to have enough "oomph" (that's a technical term) to do much to organic material *rapidly* in the water. That's not saying that UV light has no effect on organic material. Subtle difference.
And, if you think about it, the UV light has to be able to "hit" the crud in the water to chew it up. And it has to be hit with enough light to chew it up... Using a sand blasting analogy, if one photon of light is a grain of sand, one grain fired out of a sandblasting nozzle isn't going to hurt your skin that much. A steady stream of thousands of grains will remove your skin rather quickly. If the water has a bunch of "crap" (another technical term) in it, it's diffusing/scattering the light, preventing it from penetrating all through the water, making it less effective or requiring more time for it to work its magic.
Spores are a different sort of beast. They're kind of like an M&M, only instead of a "creamy chocolate inside", there's a bug (which, I guess, is a different sort of creamy...). The crunchy outer shell is a tough layer of protein, which has to be destroyed prior to getting to the bug inside. The bug typically forms the shell when conditions aren't quite right for its survival, and will "pop out" from the shell when conditions are better.
And those shells are tough... It takes some time for bleach or iodine to do their thing. Again, UV light probably could chew up those shells, but it'd take a while (this is assuming that they're not transparent to UV light, but I don't think that they are...). So it's not that they reproduce, it's that they're more like "bug seeds" that pop open and start growing again when the conditions are right.
And one final comment: You mention "UV filtration" UV exposure and filtration are two seperate beasts. You can filter out spores. They're much larger than viruses (a virus is to a bacterium much like a golf ball is to an elephant). UV is a light-based treatment. Note that with fine enough filtration, the UV pen becomes unnecessary. But (and there's always a, "But..."), the finer the pore size in a filter, the more expensive it becomes.
It all comes down to what works for you.
Doc
Gailainne
11-12-2007, 21:37
Cheers for that Doc
I knew there were some tough bu**ers out there that had a type of shell, which were impervious to a lot of filtration/cleaning techniques, wasnt sure of the details, worth a read I think tho.
I've always wondered if there is a database somewhere, in some deep dark HMG office with contaminent levels across the Country, it would be nice if rather than guessing we had an idea at least of what to expect in the area we were camping in.
Regards
Stephen
chem_doc
11-12-2007, 21:44
I should see if I can find any sort of recent studies about what nasties were found where. I may be able to find something in the "egghead" literature about that, but I have much less access to those tomes than I had in previous lifetimes...
I'll spend some time digging this weekend to see what I can come up with. It's probably not going to be super-specific, if I'm able to come up with anything at all.... And it most certainly won't be complete. And. most likely, I'll fail to find anything specific. But, I'll give it a go.
If you assume that the worst bugs are in the water, and treat it appropriately, you should be OK. ;)
Would be interested in what ever you can as long as you pass it through the "chem_Doc" filter first ;)
chem_doc
12-12-2007, 19:45
Would be interested in what ever you can as long as you pass it through the "chem_Doc" filter first ;)
Just remember, a filter removes a lot of stuff, and some of what you're trying to get through the filter gets caught up and remains in the filter... ;)
crazyclimber
12-12-2007, 20:15
The only camping UV device I'm aware of (I'm sure there are more) is the steripen (http://www.catch22products.co.uk/SteripenMicrobiological-Test.html), battery powered, I wouldnt trust one, to be frank, as I said before they are only effective if the suspended particulates are removed first (mills bag) or any kind of pre filter, there are cheaper more effective filtration systems out there, and ones that dont depend on batteries.
I've heard a lot of arguements against the steripen, of which many may be valid, but in defense of it it's still a nice quick and easy way of getting water I'm happy to drink.
In the mountains, where I spend the majority of my time outdoors, getting clear water is easy - find a stream. There tend to be very very few particulates, heavy metals and chemicals aren't an issue, the only thing to worry about is losing the bugs.
90 seconds waving the thing in the water and I've got my drink.
I know it's hardly a scientific arguement, but I've not been ill yet.
When you've got other things to worry about, sediment, chemicals etc I'd definitely agree there are better options. I've got an APT on the way which was I believe recommended by Martyn when we had this discussion a while back; although I haven't used one yet it would seem to be a very effective purification / filtration system - foolproof, reliable, and not TOO slow.
As with most equipment I guess it's just a case of matching the kit you use to what you do and where you go
chem_doc
17-12-2007, 16:46
Unfortunately, I wasn't able to find much of anything on native/wild pathogenic microorganisms and their relative abundance and locations in the UK. I have *very* limited access to anything resembling a university library, though and wonder if there's something that may be unearthed there that's not digitized/online.
sheepdogbob
17-12-2007, 17:32
At the risk of de-railing the thread: I seem to remember that some charity or other issued to the native tribesmen (and women) of a high altitude African country; clear plastic bottles that were UV transparent to semi-treat the water that they were giving to their babies, so that there was less diarrhoea and sickness. the idea was that the water was put in the bottles and put out in the sun for a period of time, then used. As I recall, they looked just like 2lt pop bottles