de-ozonation for treated potable water
de-ozonation for treated potable water
(OP)
We are taking potable water to a residence and laboratory for a fish hatchery from a supply which has been ozonated. I am trying to determine the acceptable ozone limits for potable water, and best methods (least costly and safe) to de-ozone the water prior to consumption. Some surfing has suggested that UV or activated carbon has been used but have not been able to get guidelines or details.
Any suggestions??
Any suggestions??





RE: de-ozonation for treated potable water
Simplest method may be to install a storage tank to give a residence time before use that drops the O3 level through natural losses.
If it's only potable sources that are being supplied, then a the tank may not need to be that large at all.
Michael
RE: de-ozonation for treated potable water
This is groundwater correct? Otherwise if you are supplying surface water to the resident, you have many other things to consider.
RE: de-ozonation for treated potable water
Regards
Seán
www.expertise-limited.co.uk
RE: de-ozonation for treated potable water
RE: de-ozonation for treated potable water
Re. removal of trace ozone, i've seen sodium bisulphite dosed at the outlet to an ozone contactor in an ozone/biologial activated carbon system.
A sample of the BAC output was going to a freshwater fish tank at the plant. unfortunately the fish didn't generally make it to old age - those who checked said that it was because of DO fluctuations in the feed to the tank. Some species allegedly are fairly intolerent to do fluctuation. Not being an aquarium kind of guy, i take their word for it. i don't think anyone checked out the detail as to residual ozone or excess bisulphate.
AnyLev
RE: de-ozonation for treated potable water
Keywords are "least costly and safe". Considering the surface water aspect, the thing to consider is water quality and source protection. What appears to be good one day may be a highly turbid water with embedded cryptosporidium or giardia the next day after a rain. Even ozonation of a particulate may not adequately inactivated an oocysts that is encapsulated within the particle. Therefore, most surface waters will require a multibarrier process to make it “safe”.
Ozone is just one barrier. The second barrier must be a physical removal process such as a filter or strainer. Considering only two connections, the least costly may be a point-of-entry device at each connection that is rated for turbidity removal (more specifically, giardia and cryptosporidium removal if labeled). If you have a lot of turbidity, the point-of-entry device may plug quite frequently making it intolerable to operate. In this case, a pre-filter or bag filter could be used to increase maintenance time. So the correct straining system depends on the water quality.
RE: de-ozonation for treated potable water
RE: de-ozonation for treated potable water
1. Dump all ozonated water at the back of a holding tank as far away from the delivery pump intake as possible. This gives the O3 maximum contact time and time to go through numerous half lives.
3. Dump water into the holding tank through multiple outlets to prevent stirring or tank circulation.
2. Water goes through a UV light sterilizer just before passing to the consumer. Use only UV lights that do not produce additional O3.
PUMPDESIGNER
RE: de-ozonation for treated potable water
RE: de-ozonation for treated potable water
Overseas application, power was intermittent, all water had to be made on site by RO from seawater, critical to not run out of water so large storage capacity was needed. Chlorine was not permitted.
PUMPDESIGNER
RE: de-ozonation for treated potable water
My suggested method was obviously not useable on a small system. However we always attempt simple (sometimes too expensive however) with no maintenance required.
How 'bout a smaller tank with a lot of tight baffling to create a torturous long path for the ozonated water. Dump water gently into one end of the tank, make that water travel long slow path through baffles to get to the pump intake? Add a little air bubbling if absolutely necessary Get a system like that to work and you have little or no maintenance.
PUMPDESIGNER
RE: de-ozonation for treated potable water
RE: de-ozonation for treated potable water
the contactor is a great choice, just remember for it to work it has to be vented to the atmosphere to allow for the offgassing of the ozone. It sounds like your design may not consider this. Ozone break through for ozone is extremely fast, so using this technology may not be appropriate since EBCT's will be huge to allow any type of realistic run time life for the carbon.
BobPE
RE: de-ozonation for treated potable water
Could you explain EBCT? I am not familiar with the acronym.
RE: de-ozonation for treated potable water
sure, sorry I speak technalise to save time lol...It means empty bed contact time. It is the measurement of how much carbon you will need to treat your targeted chemicals. It allows you to size the carbon contactor.
BobPE