Aug 30, 2007 at 9:27 pm #1224832
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?Aug 30, 2007 at 10:05 pm #1400594
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.Aug 31, 2007 at 8:53 am #1400610
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..Aug 31, 2007 at 10:04 am #1400622
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)Aug 31, 2007 at 10:45 am #1400626Aug 31, 2007 at 10:54 am #1400627Aug 31, 2007 at 11:37 am #1400635
Source, please? Enquiring minds want to know…Aug 31, 2007 at 11:51 am #1400637Aug 31, 2007 at 11:53 am #1400639
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.Sep 1, 2007 at 6:38 pm #1400759
@naturephoto1Locale: Eastern Pennsylvania
The Steripen on sale at REI is not the Adventurer.
RichSep 1, 2007 at 7:35 pm #1400761Sep 1, 2007 at 8:32 pm #1400763
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!Sep 1, 2007 at 9:05 pm #1400765Sep 1, 2007 at 9:26 pm #1400766
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…Sep 1, 2007 at 11:46 pm #1400771
> 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.Sep 2, 2007 at 2:25 am #1400772
"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.Sep 2, 2007 at 8:15 am #1400778
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.Sep 2, 2007 at 8:49 am #1400782
Quick note, I found the $3 UV LEDs on ebay! But I'm doubting their possible effectiveness based on the frequency.Sep 2, 2007 at 8:57 am #1400783
I'd say that you are right — those LED's are unlikely to have the "short UV" that is needed for neutralizing baddies…Sep 2, 2007 at 9:36 am #1400787
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".Sep 2, 2007 at 12:04 pm #1400796
@halfturboLocale: Northernish California
Having been interested in UV-C for awhile (originally for aquarium and pond use) I've found that the concept and technology have been in use for a looooong time. Here's an article clip discussing the Hotel Fort Des Moines (Iowa):
It cost $1.3 million to construct back in 1919, and according to general manager Paul Rottenberg, "It was built as a 'super' hotel. Every room had its own bath; there was circulating ice water to every room; and the water passed through ultraviolet light to be purified."Sep 2, 2007 at 12:23 pm #1400799
We used a UV unit to sterilize our home's water while living in the mountains of Montana from 1984 to 1994 because our water source was a spring which was prone to contamination. The water was pumped through a pressure tank, then the uv unit. It did the job efficiently and fairly inexpensively.Sep 2, 2007 at 3:17 pm #1400816
> Quick note, I found the $3 UV LEDs on ebay! But I'm doubting their possible effectiveness based on the frequency.
There's only one company in the world able to make UV-C LEDs right now, and the volume pricing on the relevant LEDs is about US$50 per unit at present.
So a $3 UV-LED from e-Bay is unlikely to work. Most likely it gives UV-A light – far too long a wavelength (too low in photon energy) to be effective.
However, given the speed of semiconductor progress, come back next year for the next exciting instalment in this saga!Sep 2, 2007 at 3:43 pm #1400818
@marti124Locale: Moderator-JohnMuirTrail Yahoo Group
I have used steripens on the trail twice, last year, I used a classic steripen which failed after 4 days of use — it got moisture in the chamber which causes it to fail. In discussions with Steripen, I was informed that their newer models are much more moisture proof than the classic. I went on a 15 day hike in SEKI this year with the steripen adventurer, and it worked just superbly. No problems. We got resupplied after day 7, and only then did I swap batteries. I averaged minimally 4 liters of water purification a day on the hike (some days 5 liters).
PS – my friend who hiked both trips with me had same gear, his steripen classic did not fail last year, thank goodness, as that was what we depended upon for the last 5 days of the trail last year. It rained 8 out of 9 days last year on the trail too (this year it did not rain even once).Sep 2, 2007 at 7:56 pm #1400836
> I used a classic steripen which failed after 4 days of use — it got moisture in the chamber which causes it to fail. In discussions with Steripen, I was informed that their newer models are much more moisture proof than the classic.
Uncommon, but I think it is now a known problem. I believe the circuit boards inside are now being coated with a moisture-proof film.
> I went on a 15 day hike in SEKI this year with the steripen adventurer, and it worked just superbly.
I used our Adventurer on and off for 3 months in France. Never gave a problem.
> We got resupplied after day 7, and only then did I swap batteries.
I took the blue 900 mA Tenrod rechargables and a solar panel I carried on the roof on my pack. Worked excellently. The rechargables have enough capacity to last for several days in case of rainy weather – which we got a lot of.
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