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Author Topic: How do UV lights clean public pool water?  (Read 7601 times)

Offline Karen W.

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How do UV lights clean public pool water?
« on: 07/04/2009 22:28:37 »
I have been going to a big hot Jacuzzi and a swimming pool for water aerobics twice a week They say they have cut all but 20 % of the chlorine by using UV light filtration.. Am I saying that properly? Anyways The pool smells great and is clean and not stingy and burning the eyes...

Could someone explain to me how this works to sanitize or clean the water?


 

Offline RD

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How do UV lights clean public pool water?
« Reply #1 on: 07/04/2009 23:11:06 »
The UV light damages the DNA sequence of the microorganisms ...

Quote
Ultraviolet (UV) disinfection involves the application of germicidal UV wavelengths to water, which damages microbial cell components and thereby prevents cell replication and renders pathogens harmless. UV disinfection has been proven to inactivate certain chlorine-resistant pathogens such as Cryptosporidium as well as a range of other waterborne pathogens. Applied at conventional UV doses, there is little to no known formation of regulated disinfection by-products associated with UV disinfection, which is an advantage over chemical disinfectants (e.g. chlorine, ozone).
http://www.ciwem.org/policy/policies/UV_disinfection.asp
 

Offline wolfekeeper

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How do UV lights clean public pool water?
« Reply #2 on: 08/04/2009 00:19:03 »
I imagine they're just pumping the water past a very bright UV lamp. UV has very high energy and chops up the DNA in the bacteria.

The only gotchas I know of are that it only kills the bacteria that's floating in the water, so they still have to keep the pool walls clean, and if there's dirt in the water that the light doesn't penetrate, then the bacteria can hid inside, so they have to filter the dirt out as well before going past the UV lamp.

Similar stuff is used for drinking water.
 

Offline Karen W.

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How do UV lights clean public pool water?
« Reply #3 on: 08/04/2009 04:58:47 »

The UV light damages the DNA sequence of the microorganisms ...

Quote
Ultraviolet (UV) disinfection involves the application of germicidal UV wavelengths to water, which damages microbial cell components and thereby prevents cell replication and renders pathogens harmless. UV disinfection has been proven to inactivate certain chlorine-resistant pathogens such as Cryptosporidium as well as a range of other waterborne pathogens. Applied at conventional UV doses, there is little to no known formation of regulated disinfection by-products associated with UV disinfection, which is an advantage over chemical disinfectants (e.g. chlorine, ozone).
http://www.ciwem.org/policy/policies/UV_disinfection.asp


That is great RD Thanks so much... so overall it actually is more effective then just straight chlorine. Seems the other benefits really add to the whole positive aspect.. like no burning eyes and less harsh to the skin etc.. not too mention the ozone!

I imagine they're just pumping the water past a very bright UV lamp. UV has very high energy and chops up the DNA in the bacteria.

The only gotchas I know of are that it only kills the bacteria that's floating in the water, so they still have to keep the pool walls clean, and if there's dirt in the water that the light doesn't penetrate, then the bacteria can hid inside, so they have to filter the dirt out as well before going past the UV lamp.

Similar stuff is used for drinking water.


Thanks wolfekeeper.. I think that is a given but I will check.. I did notice some wall dirt, like ring around the collar... around the top very light so I assume they have someone come in a clean that regularly! And I believe The filter is also in place..

Thanks The information you both provided is greatly appreciated!
 

Offline lightarrow

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How do UV lights clean public pool water?
« Reply #4 on: 08/04/2009 16:09:39 »
I imagine they're just pumping the water past a very bright UV lamp. UV has very high energy and chops up the DNA in the bacteria.

The only gotchas I know of are that it only kills the bacteria that's floating in the water, so they still have to keep the pool walls clean, and if there's dirt in the water that the light doesn't penetrate, then the bacteria can hid inside, so they have to filter the dirt out as well before going past the UV lamp.
Yes, but they  filter the water in any case, UV or non UV. First water is filtered (sand filters, diatom filters or else) then disinfected and reintroduced in the pool.
« Last Edit: 08/04/2009 16:15:01 by lightarrow »
 

Offline Karen W.

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How do UV lights clean public pool water?
« Reply #5 on: 08/04/2009 16:24:31 »
Thanks Alberto.... Very glad to see you Posting........ Where are you in relative ...area of the earthquake?
 

Offline lightarrow

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How do UV lights clean public pool water?
« Reply #6 on: 08/04/2009 20:28:07 »
Thanks Alberto.... Very glad to see you Posting........ Where are you in relative ...area of the earthquake?
My town is about 180 km from the area of Earthquake. We felt it, but nothing more than that.
 

Offline Bored chemist

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How do UV lights clean public pool water?
« Reply #7 on: 09/04/2009 16:30:53 »
Chlorins seems to me to havea couple of advantages. First, if you can't smell it you know something has gone wrong. Secondly it reaches all the places where the water gets to. With a UV system you can get a build up of bacteria etc on the walls of the pipes and so on where the UV can't reach- Chlorine reaches everywhere.
Having said that, chlorine stinks and some of the by products of its reactions are environmentally unfriendly. Ozone based systems look like a good idea to me.
 

Offline lightarrow

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How do UV lights clean public pool water?
« Reply #8 on: 09/04/2009 21:33:34 »
Chlorins seems to me to havea couple of advantages. First, if you can't smell it you know something has gone wrong. Secondly it reaches all the places where the water gets to. With a UV system you can get a build up of bacteria etc on the walls of the pipes and so on where the UV can't reach- Chlorine reaches everywhere.
Having said that, chlorine stinks and some of the by products of its reactions are environmentally unfriendly. Ozone based systems look like a good idea to me.
Also, there is another advantage in using oxidant chemicals: you exploit the same mean for two purposes; infact they react destroying the organic compounds (total organic compounds is a controlled parametre in pool's water, from sanitary officials, at least here in Italy) and you can't do it with UV.
 

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How do UV lights clean public pool water?
« Reply #8 on: 09/04/2009 21:33:34 »

 

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