WEF Discussions — Now on LinkedIn!

WEF is pleased to announce the creation of free LinkedIn groups associated with its technical discussion forum topics. Through these LinkedIn groups, members will be able to view and participate in discussions, as well as communicate with one another via direct messages. Share your experiences and knowledge, ask questions and respond to other discussions as frequently as you like!

You must have a LinkedIn profile to join a LinkedIn group; you can create your profile here. If you already have a LinkedIn profile, all you need to do is submit a request to join one or all of the following groups:

Water Environment Federation (Main) | Biosolids | Collection Systems | Nutrients | Stormwater 
Utility Management | Water Reuse | Water for Jobs | Watershed Management | Laboratory Practices 

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Request for info regarding Trojan UV systems
Posted: Thursday, December 9, 2010 11:04 AM
Joined: 12/9/2010
Posts: 2

Anybody have any feedback on experiences with TROJAN UV? Likes / Dislikes! Any plants in KS, MO have TROJAN UV system in place?

Posted: Tuesday, December 21, 2010 9:36 AM

yes we have the second biggest one it is a 300 plus and it sucks and not joking very expensive to run and not real good at dealing with and extra soilds loading if you have any operatioal problems or even winter. op's it would work great with filters a head but if not the best look to europe they are taking it out>>> and going with ozone.

Posted: Tuesday, December 28, 2010 7:53 AM

Transmittance testing is very Important when making the leap to U.V. sterilization. Effluent transmittance #s should be no less than 60 when doing the testing. The lower the #s the more Hydro and more expensive the unit is going to be and more Maintenance cleaning the bulbs and fouling of the bulbs requiring changing more often, otherwise there should not be any problem. The only thing I don't like is the fact that you cannot do a residual like Chlorine, you are at the mercy of waiting for the test results from the Lab which takes a few days. Takes a little getting used to but seems to be relatively trouble free. Trojan is the only unit I'm familiar with.

James Royer
Posted: Wednesday, December 29, 2010 12:01 PM
Joined: 9/21/2009
Posts: 98

The thing about UV is that to maintain the proper dosage you must maintain a constant amount of TSS as they block the energy penitration. If you have a backup chlorine system you could feed a small amount of chlorine during the higher TSS episodes. There is a good synergy effect.


Chlorine residual may give you a false sense of security as different forms of combined chlorine have varied disinfecction properties. I just operate the plant maintain a constant chlorine dosage that I know will give me good results at the current contact time. As flow increases you adjust the chlorine dosage higher as the contact time is reduced.


Monitoring the UV transmittance is important, as lower transmittance effectively reduces the energy dosage, and adjustments must be made. Normal variation in %T should be known prior to committing to UV disinfection.

B Lewis
Posted: Tuesday, October 25, 2011 7:01 PM
Joined: 10/25/2011
Posts: 1

We are starting up a new UV system and are having difficulty with consistent UVT readings.  The results are stable for several hours then rapidly - over a few minutes swing from 70 to 50 or lower several times for a few hours - then stable again.  Water quality does not appear to change.  The rapid swings results in all the banks turning on at 100% since it is below the validation range of 55, or dosage higher than what would be expected.  We do not yet have a portable UVT to confirm the values.  What has been your experience with consistency of UVT results and do you have a favorite UVT meter manufacturer? 


Thank you for your help. 

Posted: Friday, August 10, 2012 2:22 PM
Joined: 12/15/2009
Posts: 5

complicated and costly. If you have a good I.T. guy to keep all the bell and whistles going it has the potential of working well.