chlorination question

[angler_management]

I have the following water values and Iron bacteria. hardness 16 - Iron 1.1 -sulphur .2 -PH 7.2.
I am planning on installing a chlorinator --> retention tank --> backwashing carbon filter --> softner.
what is the minimum ppm of chlorine will I need? Can the sulphur precipitate out first and leave most of the iron for the softner or do I take care of them both at the chlorination stage?
I would like to use the minimum amount of chlorine possible.

TIA!

[Gary Slusser]

If you are thinking of using a solution feeder, you probably won't like it long. Most folks don't because they take a lot of baby sitting. They also take up a lot floor space if you sue the proper size retention tank.

If you're planning on a solution feeder, I'd suggest an inline erosion pellet chlorinator with a special mixing tank that is equivalent to a 120 gal retention tank.

If you have the chlorination set up properly all the iron, IRB and H2S etc. will be oxidized and then removed with the carbon filter IF it is sized and set up correctly. Otherwise you'll foul the carbon, it will fail and then the softener will see dirty water and soluble iron and it will fail.

IIRC it is said that you need 4 ppm chlorine per ppm of iron, but don't depend on that, I hate feeders and haven't set one up for many years. You also need a minimum of 20 minutes retention before the oxidation is complete. Meaning that the water is in contact with the chlorine for at least 20 minutes before the water exits the first fixture.

Gary
Quality Water Associates

[angler_management]

Thanks for the response.
I am planning on using the erosion type chlorinator and tank. Will 4ppm get rid of all iron and sulphur? How would the Carbon filter get mucked up if I say run a 2ppm and just oxidize some of the sulphur and iron and let the softner do the rest? Just trying to get as much info as possible before moving forward.

Thanks

[Gary Slusser]

Softeners don't remove or reduce H2S but... there's little sense in having a chlorination system and then not have it do the whole job; which says it isn't set up correctly or you don't have the proper retention (time). I can't tell you how much chlorine but you dose until there is no odor or iron remaining in the water and you have 2. to.5 ppm of free chlorine before the carbon.

Are you using a retention tank or special mixing tank? If the mixing tank, and the patented version of the erosion pellet chlorinator instead of the knock off type, then set your chlorine at the minimum dose (A1 IIRC) and it's done. Don't bother testing for the amount of chlorine as long as there is chlorine in the water before the carbon filter.

Gary
Quality Water Associates