Using UV to remove chloroamine

[dkeller_nc]

0.2ppm chloramine.

If that's your tap water, that does sound a bit low. Typical chloramine levels in municipal systems is in the 2-4 ppm range. However, one would expect the chloramine to degrade the farther one is from the treatment plant, the longer the water stays in the piping, and the TOC levels of the water.

 

[Raul-7]

I left the sample overnight; it's now 0.6 ppm.

 

[zachfishman]

I wouldn't rely on any analog kit to objectively test chlorine/chloramine in these circumstances (unless I am looking for zero or not-zero). We use these at work: Hanna Total Chlorine Checker

I investigated using UV to dechlorinate (if it's chloramine, is it "dechloraminate"?) at work. The scale at which it is more economical than carbon was simply too great, and we ended up just upgrading our carbon prefiltration.

 

[Raul-7]

I ordered it. I'm tired of this color matching.

 

[Raul-7]

I investigated using UV to dechlorinate (if it's chloramine, is it "dechloraminate"?) at work. The scale at which it is more economical than carbon was simply too great, and we ended up just upgrading our carbon prefiltration.

Why not? How much mJ/cm2 of UV does it require to photolyze 1 ppm of chloramine?

 

[zachfishman]

Why not? How much mJ/cm2 of UV does it require to photolyze 1 ppm of chloramine?

I couldn't even get quoted by our usual RODI suppliers (AquaFX, Buckeye Hydro). The only references to UV dechlorination I could find were industrial, and nowhere could I find listed any product specs offering reduction of X ppm chlorine/chloramine per X gpm...

For the heck of it I tried running our tap through a 57w UV sterilizer to see what gpm resulted in what reduction of chlorine. I never got consistent results, but I think the best reduction I got was removing maybe ~1ppm chlorine at <0.25gpm. For my needs (4gpm, ~4ppm chlorine) I'd need 64 times the UV exposure!

 

[Raul-7]

I guess I'll return the UV unit then; seems like a lost battle.

 

[zachfishman]

I guess I'll return the UV unit then; seems like a lost battle.

You can always try it and let us know how it goes. There are numerous under-the-sink tap water sterilizers, but they don't dechlorinate as far as I can tell. They may advertise this, but I doubt the effect is significant - let alone complete dechlorination us reefers require. At least that's what I surmise from my test with the 57 watter.