Yet another water purifier?

[Tiley]

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.

 

[Jared]

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.

 

[spamel]

These are on issue to my brothers' unit. He says they are awesome.

 

[Toddy]

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

 

[Ed]

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]

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 to a recent discussion.

Stephen

 

[Toddy]

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

 

[Jared]

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]

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.

 

[SMARTY]

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]

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.

 

[chem_doc]

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

 

[Jared]

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.

 

[Toddy]

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

 

[SMARTY]

Would be interesting to know the reason why.

Size, cost, results.

 

[dwardo]

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

 

[CLEM]

I picked this one up yesterday for a fiver

http://www.bushcraftuk.com/forum/showthread.php?p=353914#post353914

 

[Gailainne]

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, 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]

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]

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, 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