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Home > Archive > Alternative Power sources > July 2005 > UV LEDs for water sterilization?
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UV LEDs for water sterilization?
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| Danno 2005-07-08, 11:25 pm |
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Not specifically power generation, but thought perhaps some rainwater
collectors might know the answer?
Do the emmisions from UV LEDs correspond with the proper wavelength(s) to
sterilize water in the same way that current UV lights work?
For instace, could this:
http://cgi.ebay.ca/ws/eBayISAPI.dll...item=5217375103
Be used in the same manner as this:
http://www.hydro-photon.com/
--
Solar-powered Linux: Slackware 10.0, 2.6.12, Averatec 3250H1 w/accel S3Uni
RLU#272755
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| Danno wrote:
quote:
> Not specifically power generation, but thought perhaps some rainwater
> collectors might know the answer?
> Do the emmisions from UV LEDs correspond with the proper wavelength(s) to
> sterilize water in the same way that current UV lights work?
>
> For instace, could this:
> http://cgi.ebay.ca/ws/eBayISAPI.dll...item=5217375103
>
> Be used in the same manner as this:
> http://www.hydro-photon.com/
>
good question ? . tube is probably better . the way I understand uv
serilization is that it is performed on the delivery side (after pump)
so could prop be sw with the pump controle ?
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| samc wrote:
quote:
> Danno wrote:
>
> good question ? . tube is probably better . the way I understand uv
> serilization is that it is performed on the delivery side (after pump)
> so could prop be sw with the pump controle
p.s do wait for other replys as the above is just a guess
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| SQLit 2005-07-08, 11:25 pm |
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"Danno" <TOOmuchSPAM@hotmail.com> wrote in message
news:slrndctppa.2dd.TOOmuchSPAM@3250H1.danux.net...
quote:
>
> Not specifically power generation, but thought perhaps some rainwater
> collectors might know the answer?
> Do the emmisions from UV LEDs correspond with the proper wavelength(s)
to
quote:
> sterilize water in the same way that current UV lights work?
>
> For instace, could this:
>
http://cgi.ebay.ca/ws/eBayISAPI.dll...item=5217375103
quote:
>
> Be used in the same manner as this:
> http://www.hydro-photon.com/
All of the UV I have worked about were tubes. Pleasanton Ca has over a
megawatt of UV in one of their freshwater plants. I would think you would
not care for the load and number of lamps it would take to clean the water.
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| Danno 2005-07-08, 11:25 pm |
| On 2005-07-08, SQLit <sqlit@qwest.net> wrote:
quote:
>
> All of the UV I have worked about were tubes. Pleasanton Ca has over a
> megawatt of UV in one of their freshwater plants. I would think you would
> not care for the load and number of lamps it would take to clean the water.
>
<nod>, I suspect that it would take quite a few LED modules to do the job,
maybe covering the entire inside of a tank's cap. My personal interest is of
a much smaller capacity, something along the lines of a litre or 1/2 litre
at a time, when I am hiking for instance. I would prefer to use LEDs because
they seem, in my experience, more robust. I am speculating that they would be
more energy efficient than tubes as well, but that it pure conjecture on my
part.
--
Solar-powered Linux: Slackware 10.0, 2.6.12, Averatec 3250H1 w/accel S3Uni
RLU#272755
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| Steve Spence 2005-07-09, 4:25 am |
| Fluorescents are much more efficient than LED's on a lumen per watt basis.
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html
Danno wrote:
quote:
> On 2005-07-08, SQLit <sqlit@qwest.net> wrote:
>
>
>
> <nod>, I suspect that it would take quite a few LED modules to do the job,
> maybe covering the entire inside of a tank's cap. My personal interest is of
> a much smaller capacity, something along the lines of a litre or 1/2 litre
> at a time, when I am hiking for instance. I would prefer to use LEDs because
> they seem, in my experience, more robust. I am speculating that they would be
> more energy efficient than tubes as well, but that it pure conjecture on my
> part.
>
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| William P. N. Smith 2005-07-09, 4:25 am |
| Danno <TOOmuchSPAM@hotmail.com> wrote:
quote:
> Do the emmisions from UV LEDs correspond with the proper wavelength(s) to
>sterilize water in the same way that current UV lights work?
WCP magazine talked about this recently:
http://www.wcponline.com/PDF/0505%20UV%20treatment.pdf
That says UVC, 200-280nm, quartz tubes, etc.
quote:
>http://cgi.ebay.ca/ws/eBayISAPI.dll...item=5217375103
Doesn't say anything about the wavelength, but even if it was UVC I'd
doubt that the power levels are high enough.
quote:
>http://www.hydro-photon.com/
I'd be surprised if that had high enough power levels too, but they
seem to be selling it... 8*)
I thought that eyes were damaged by UVC, and you had to have a shield,
but maybe I'm thinking of 'vacuum UV' which is used to make ozone for
water purification...
Lots of good stuff at the WPConline site, search on ultraviolet
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| On 2005-07-09, Steve Spence <sspence@green-trust.org> wrote:
quote:
> Fluorescents are much more efficient than LED's on a lumen per watt basis.
>
>
Does that fact still hold at the wavelengths we are referring to? I realize
that at the visible wavelengths this is true, but when we move into higher(?)
wavelengths, do the efficiencies still exist?
--
Solar-powered Linux: Slackware 10.0, 2.6.12, Averatec 3250H1 w/accel S3Uni
RLU#272755
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| Winston 2005-07-09, 4:25 am |
| Danno wrote:
quote:
> On 2005-07-09, Steve Spence <sspence@green-trust.org> wrote:
>
>
> Does that fact still hold at the wavelengths we are referring to? I realize
> that at the visible wavelengths this is true, but when we move into higher(?)
> wavelengths, do the efficiencies still exist?
Even more so, relatively speaking.
All fluorescent lights are mostly ultraviolet. The phosphor coating converts
a portion of the UV to visible light.
http://home.howstuffworks.com/fluorescent-lamp2.htm
--Winston
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| Duane C. Johnson 2005-07-09, 6:25 pm |
| Hi Steve;
Steve Spence <sspence@green-trust.org> wrote:
quote:
> Fluorescents are much more efficient than
> LED's on a lumen per watt basis.
Yes, the efficiency of mercury vapor tubes are
much more efficient than UV LEDs on a light
power basis. However, I can't find a definitive
reference on either efficiency.
Nit pick on!
On the other hand, there is no lumen output
from UV lamps of any amount. Technically a lumen
is a measure of the ability of the human eye
to perceive the light. Since the eye can't see
UV, or infra red for that mater, there are no
lumens.
quote:
> Steve Spence
> Dir., Green Trust, http://www.green-trust.org
> Contributing Editor, http://www.off-grid.net
Duane
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| |
| Don Bruder 2005-07-09, 11:25 pm |
| In article <slrndcuaco.2te.TOOmuchSPAM@3250H1.danux.net>,
Danno <TOOmuchSPAM@hotmail.com> wrote:
quote:
> On 2005-07-08, SQLit <sqlit@qwest.net> wrote:
>
> <nod>, I suspect that it would take quite a few LED modules to do the job,
> maybe covering the entire inside of a tank's cap. My personal interest is of
> a much smaller capacity, something along the lines of a litre or 1/2 litre
> at a time, when I am hiking for instance. I would prefer to use LEDs because
> they seem, in my experience, more robust.
As in "less subject to damage from physical shock/vibration, yes."
quote:
> I am speculating that they would be
> more energy efficient than tubes as well, but that it pure conjecture on my
> part.
Perhaps...
Trouble is, UV LEDs are notoriously short-lived compared to their
visible and infrared outputting cousins. Typical advice I keep hearing
anytime I go looking at UV LEDs for whatever reason is to expect them to
be functional for less than a tenth of the usual lifespan of a visible
or IR LED.
That's problem 1.
Problem 2:
UV, blue, and white LEDs are serius power-suckers as far as watts per
light-unit of output. To feed them, you need more power than IR or
visible LEDs - Dont expect your batteries to last long...
Problem 3:
The wavelength. I'm certain that it's *POSSIBLE* to get LEDs that put
out the right kind of UV, but I doubt that any "off the shelf" units can
be had for a decent price, or without being special-ordered.
Problem 4: (Which ties into problems 1 and 2)
When your batteries and/or UV LEDs go dead, how do you propose to find
this fact out? UV is, by definition, invisible, so flipping the switch
is going to be one of those "I wonder if it's working?" things unless
you've got some way to verify (perhaps a UV-sensitive camera you can
point at it?), which in turn makes your "sterilizer" pretty much
useless, at least in my eyes - "I can't be *CERTAIN* it's functioning as
intended, so there's no way to know whether what's coming out of the tap
is safe to drink"
I suspect you'd be *MUCH* better off sticking with a UV tube and a power
supply to feed it - At least then you can be sure that you've got the
right kind of UV happening, and you've got a visual indication (UV tubes
aren't anywhere near as monochromatic as LEDs are, so there's always at
least SOME visual indication that tey're operating)
Oh... Some advice: *DO NOT STARE INTO UV SOURCE WITH YOUR REMAINING
EYE!* 
Better yet... There's this spiffy new concept called "Iodine tablets"
that is intended specifically for purifying "survival"/hiking/etc water
water... I Keep hearing rave reviews about them being quite useful, and
requiring zero power input (unless you count the power you use in
scooping the water out of whatever source you find it in...)
If you ABSOLUTLEY MUST go the UV route, I'd suggest one of those
coleman/etc. lights that has the small flourescent tube in it - Just
replace the normal tube with a "barber's lamp" (remember when barbers
had a little toaster-oven looking thing filled with a queasy bluish
light that they'd park combs and scissors in between customers? The
bulbs for those...) to get raw UV instead of white light.
--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See <http://www.sonic.net/~dakidd/main/contact.html> for full details.
| |
| Bruce in Alaska 2005-07-09, 11:25 pm |
| In article <42cee9a2$1_3@mk-nntp-2.news.uk.tiscali.com>,
samc <remprefix.samuel.7scrubthis9@tiscali.co.uk> wrote:
quote:
> Danno wrote:
> good question ? . tube is probably better . the way I understand uv
> serilization is that it is performed on the delivery side (after pump)
> so could prop be sw with the pump controle ?
I have a GE Germacidal T10 tube in my water system and it runs off a
12Dvc Ballast/Powersupply that is on the Enabled side of the Pressure
Switch for my Dankoff Solar Domestic Water Pump. The tube is surrounded
with a Quartz Glass water chamber that can handle the 7GPM that my
system can supply for the cabin. Water is Prefiltered at 10 Microns,
and then run thru a 50 Micron Activate Charcoal Filter before the UV
Unit. I do filter changes twice a year. Total yearly cost are
about $35US and $25US for a new, tube biannually.
Bruce in alaska
--
add a <2> before @
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| JoeSixPack 2005-07-12, 11:25 pm |
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"Danno" <TOOmuchSPAM@hotmail.com> wrote in message
news:slrndctppa.2dd.TOOmuchSPAM@3250H1.danux.net...
quote:
>
> Not specifically power generation, but thought perhaps some rainwater
> collectors might know the answer?
> Do the emmisions from UV LEDs correspond with the proper wavelength(s) to
> sterilize water in the same way that current UV lights work?
>
> For instace, could this:
> http://cgi.ebay.ca/ws/eBayISAPI.dll...item=5217375103
>
> Be used in the same manner as this:
> http://www.hydro-photon.com/
I don't think the power draw of LED's would give you much of a cost
advantage over all. I'd wait until the work is done to certify them for
that use. Until then, I wouldn't risk my health on it.
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