Sterilization of water can be accomplished with UV light. Products like Steripen and Hydrophoton use this principle with lights costing about $110+
But, UV lights have proliferated due to their commercial use in detecting fake bills, casino chips, etc.. Would a $3 UV light from ebay work just as well?
Microbiology is not my field, so I can not give an authoritative answer; can anyone else?

Brett:

I asked a similar question earlier and got some good answers. If you haven't seen them before, click here. Read the responses from Miles Maiden, etc.

Edited by ben2world on 08/30/2007 23:07:54 MDT.

Thanks Ben, I am definitely one of the cheap bastards.. and that answered my question with a 'no', because I was looking at UV lights around 300 to 400 nm.. Ill look for one at about 250..

Hey, if you find anything, let me know! :)

In the meantime, REI is having a sale on Steripen. Still kind of steep IMO, but it comes with a hard-sided water bottle -- which you can use to house your hard to pack caldera cone! (heh heh)

Edited by ben2world on 08/31/2007 11:07:37 MDT.

steripen $79 with this url
http://www.rei.com/product/745185

According to the most recent Army research, UV light is not any good at killing viruses and pathogens. Who should I believe?

David:

Source, please? Enquiring minds want to know...

Ben, about half way down the page:

http://chppm-www.apgea.army.mil/WPD/Updates.aspx

The rest of the site is interesting as well.

David:

Thanks for the link. Reading "Table 5", this is what I got:

1. Viruses are more resistant to UV than other baddies (bateria, protozoa including cysts, giardia and crypto)

2. Thus, any dosage high enough to treat viruses will also be effective for treating the other baddies.

3. UV effectiveness is NOT affected by water temp.

4. UV effectiveness is NOT affected by water pH.

5. UV effectiveness IS affected by water turbidity


My understanding is that Steripen dosage is more than strong enough to handle viruses (and thus everything else as well). Just about the only caution is the treatment of turbid water -- which may require an additional effort of screening out particulates -- or waiting time for particulates to settle.

Edited by ben2world on 08/31/2007 13:16:12 MDT.

Jaiden,

The Steripen on sale at REI is not the Adventurer.

Rich

Ben,

"this device did not meet the required log reductions in relatively clear type 1 water. Based on this testing, it is not likely that this device will consistently meet the log reduction requirements under any water conditions."

Hence, it failed. Am I missing something? I do question why the product does not come with information on independent tests completed - i.e. nothing in the manual.

David:

I navigated to Table 5 and didn't see the sentences you quoted above. I found it now, and I quote the entire paragraph:

***********************************************************************************************

"Hydro-Photon SteriPEN™ Device Evaluation Update – February 2006

Independent laboratory results were received that tested the Hydro-Photon, Inc., SteriPEN against the USEPA Guide Standard. Testing was conducted using the UV portion of the protocol with a production volume of 4 L/day for 10.5 days. Testing was conducted in 16-32 oz. batches. Testing followed the dosimetry method described in NSF Standard 55 that measures UV dose and correlates it with MS-2 kill. Based on the MS-2 stock used, a kill of 2-log or greater was determined to be adequate to be considered a water purifier, and therefore, effective at reducing pathogens. Collimated beam testing indicated that this reduction equated to a dose of 40 mJ/cm2. Results indicated that this device did not meet the minimum log reduction requirements based on MS-2 kill. Initially, this device did meet the 2-log required reduction, but this reduction decreased by Day 6. On the following days, under higher turbidity water, the device performed poorly, with less than 1-log kill. This performance is expected in turbid waters where UV transmittance is limited. The turbidity levels during this testing were 100-470 NTU, well above the ≥30 NTU requirement, however, this device did not meet the required log reductions in relatively clear type 1 water. Based on this testing, it is not likely that this device will consistently meet the log reduction requirements under any water conditions. There is no change to the pathogen reduction ratings previously stated (bacteria, virus, Giardia, Cryptosporidium)."
****************************************************************************************************

I think someone just did a poor job condensing what were likely pages of results into one paragraph -- and an incoherent one at that! Reading the above, it seems like they found the Steri-pen effective initially (i.e. initially achieving log 2 kill rate... until Day 6..., when turbid water was used instead, and performance fell, which one would expect. So far so good, until finally, and very confusingly, the report ends with a pretty damning sentence of clear ineffectiveness!

My only conclusion now: This report reflects the usual ARMY SNAFU. I assume ye Canucks understand the acronym? :)

In any case, I am waiting for Brett to find those $3 UV LED equivalents. He's probably pimping the streets of Tokyo right now!

Edited by ben2world on 09/01/2007 21:40:41 MDT.

Yes, confusing I agree. Frustrating a little, actually.

It seems that to get total coverage, at least in as short a time frame as possible: Filter plus chemicals or Filter plus Steripen.

Kind of moot for me anyway as most of the water I come across is quite clear to begin with - I could probably feel comfortable with the Steripen....except that it really only purifies 1L at a time, which is a bit of a problem with a 2L hydration bag ;).

Perfect gear...where art thou; my wallet is getting thin 'trying' things out.

David:

I think "clear but cold" water is where UV outshines chlorine dioxide! Doesn't solve the 2L bottle problem though -- unless you are willing to bring a 1L bottle along for pouring treated water into your bigger containers...

> I think "clear but cold" water is where UV outshines chlorine dioxide!
Well, 90 seconds sure beats 4 hours...
Yes, turbid water is a problem, but let's be realistic: only the Army would expect users to drink it. In the mountains we very rarely need to even worry about turbidity. Yes, I have met opaque water - about twice in 10 years. I am prepared to boil that.

> Doesn't solve the 2L bottle problem though -- unless you are willing to bring a 1L bottle along for pouring treated water into your bigger containers...
I use my cooking pot, and treat 1 L at a time. Gives me a 2 minute rest for each litre. Can't see any problem with that.

"this device did not meet the required log reductions in relatively clear type 1 water. Based on this testing, it is not likely that this device will consistently meet the log reduction requirements under any water conditions."

If you read the whole paragraph again, it met requirements for the first 6 days of a 10.5-day test of producing 4L per day. Only after that point when the batteries were getting low did it fail to meet requirements. The take home message is to replace the batteries at about 20L if you want to maintain full performance.

When these test results were brought to my attention some time ago, I wrote to Steripen and they provided me with a bunch of material which I sent along to others on another forum. I don't believe I still have it. Some of the material was from independent testing done in Canada as I recall.
Anyway, I was satisfied with the results and am comfortable with my Steripen in the backcountry and out of the country.
Viruses, I beleive, are not much of an issue in North America anyway but I have used the Steripen in pretty suspicious water in Mexico and central America without any ill effects.

Ben,
Quick note, I found the $3 UV LEDs on ebay! But I'm doubting their possible effectiveness based on the frequency.

http://cgi.ebay.com/Super-BRIGHT-3-UV-LED-Flashlight-Keychain-Black-Light_W0QQitemZ230166870184QQihZ013QQcategoryZ16037QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Brett:

I'd say that you are right -- those LED's are unlikely to have the "short UV" that is needed for neutralizing baddies...

Edited by ben2world on 09/02/2007 11:36:53 MDT.

According to an independent test on turbid water -- noting that results were pulled from Steripen's own website -- doubling the treatment time can increase the "kill rate" to meet EPA standards for viral and bacterial purification.

But how turbid is turbid? Below is a photo from the test above. If one can indeed treat water as turbid as the glass below by simply doubling the UV dosage, that should give hikers a reasonable "comfort level".

Edited by ben2world on 09/02/2007 10:38:10 MDT.