hmm..pretty rare that chlorine/chloramines are not used.
Ozone is an effective method of disinfection for several reasons:
1. it is very good at oxidizing compounds that cause taste and odour issues.
2. it is very effective against crypotosporodian oocysts which can 'hide' in particulate matter and be protected from chlorine. chlorine works as a surface disinfectant. if the pathogen is sheilded, it cannot get to it.
However, the reason that chlorine/chloramines are used is that they provide protection from the point the water leaves the treatment plant to the point it comes out of your tap.
in other words, there is what is known as a 'free chlorine residual' that remains able to disinfect as the water moves through the piping system.
so you are safe when the water comes out your tap.
with ozone, there is no such residual. it is effective at the point of treatment only.
check with your water company about their methods of disinfection.
in my area, chlorine/chloramines (chlorine + ammonia) is used along with ozone. so there are several barriers to protect the public.
the reason that chloramines are used is that they are very stable. they remain in the water for some time to protect you.
free chlorine is highly reactive and loves to be 'used up' by just about anything it comes in contact with.
chlormamines are more stable but are actually not as good of a disinfectant as free chlorine.
okay, thats about all I know. I am a wastwater treatment operator, so I know a little because the processes are similar. but for more detailed info, you need to speak to an actual drinking water operator (ie contact your local plant)
hope this helps.
