Chlorine injection placement

[Wolf911]

I read that the chlorine or peroxide injection system should be before a backwashing iron filter but haven't found any info on how close to the iron filter it should be. My question is does it matter how far from the iron filter(pyrolox) the chlorine injection takes place?

Does it matter if the chlorine injection system was in the pumphouse a 100ft away and the iron filter was in the house utility room?

I really would like to keep the chlorine injector in the pumphouse but have some concerns that alot of iron sediment might accumulate in the 1" line from the pumphouse to the house over the years. This concern arose after I put some chlorine into a gallon of well water and let it set a few days and saw the Iron sediment on the bottom of the jug . I thought all that sludge could end up in the line instead of the iron filter. Maybe my concerns have no merit but I thought its better to ask than to end up with a reduced flow water line 10yrs from now because of buildup .
Also would that distance from the point of chlorine injection (100ft away) to the iron filter have any bearing on the iron filters ability to work as it should?

The flow thru the line from the pumphouse to the house will be low 1 .6gpm most of the time because its only feeding my RO unit. Iron is 2ppm.
I don't have a contact tank installed in the pumphouse because I thought the low flow rate would be sufficient contact time, but now I'm wondering if I need the tank to keep the iron particles from settling in the line.
I could possibly move the chlorine injection to the house close to the iron filter but definitely don't have room for a contact tank in the house. I do have room in the pumphouse for a contact tank. I'm in the installation stage now and trying to get things right so I don't have to redo them later.
Thanks for any advice.

 

[Reach4]

Does it matter if the chlorine injection system was in the pumphouse a 100ft away and the iron filter was in the house utility room?

After the injection, there will be precipitate. What happens to that? If there is nothing to deal with that, I expect it would settle out. Your fears are justified. If the injection is continuously uphill from the iron filter input, I expect the precipitate would make it to the iron filter, where it gets filtered out and backwashed away. I am not a pro. If you have a good contact tank, that will collect the sediment. The Pyrolox should not have much left to do. You could replace that with a GAC tank to remove the residual chlorine.

Pyrolox needs a high backwash rate, so your pump and piping have to be able to supply that.

 

[Sponsor]

 

[ditttohead]

Typically injecting as far as reasonable from the iron reduction system is preferred but the pipe must be easily replaceable. Otherwise, do it closer. Here is a great picture showing why.

 

[Wolf911]

Thats a scary picture dittohead. I certainly can't take a chance that my main water line could become plugged like that.
Is that picture a direct result of chlorine injection a long distance from the iron reduction system or do you know if there was also other issues?
The way I see it these are the options I have

1) don't install the chlorine system at all and just rely on the pyrolox filter and my GAC filter(I doubt the GAC will do anything for the iron without the chlorine) to remove the 2ppm iron and the .75ppm manganese. The orp is 249mv and the pH is 7.66

2)install the chlorine pump in the pumphouse and install a larger than normal contact tank and maybe some sort of inline filter to catch anything getting by the contact tank. Don't know how effective the filter would be or how often id have to change it? Keep the iron and GAC in the house with RO unit.

3)install the chlorine injection in the house without contact tank( no room for contact tank) in the short 3ft line before the iron filter. Could that work in such a short distance?

Which option do you think is best? I guess I could try option 1, if it didn't get the iron and manganese then try option 3 , and finally option 2.
Of course id rather get it right the first time and not have to redo things.

 

[Bannerman]

Possible alternative to option #2: Relocate the Iron Filter to the pumphouse and locate the GAC filter system inside the home.

Although you are only requiring 10 GPM for the 8" diameter Pyrolox filter, moving it closer to the well pump could help to supply the flow rate needed to backwash that media. A 100' run of 1" to feed the iron filter, maybe causing a flow restriction, particularly if the pipe run is partially obstructed with internal fittings and iron debris.

 

[Water Pro]

does your raw water have an odor?

 

[Wolf911]

Thanks for your advise guys
.
Bannerman I know that the best option would be to move the iron filter down to the pumphouse but I already have almost everything set up in the house. I don't want the iron and carbon backwashing filters in the pumphouse because I don't have a drain there and made a separate dry pit for them to backwash into close by the house. Also I want things like that close so I can check that they are working properly. I have checked the flow right before the pyrolox filter and with just the well pump going and nothing in the pressure tank I still have the 10gpm. Although I learned from you guys that because my water is cold, 47degrees I might not even need the full 10gpm.

Yes waterpro i have a slight rotten egg odor(sulpher) but it dissipates pretty quick when it sets for a few minutes.

I have never looked into contact tanks but just today while browsing i saw some 15 and 30 gallon ones that are tall and skinny (10",12"). None of them said anything about baffles though. So I don't know if there any good. I saw a clack tank with baffles but that was 21" wide. If I could use one of the 10" or possibly 12" tall skinny ones, I think I can find a way to fit it into the house utility room and put every thing including the chlorine injection there. It will be cramped.
Does anyone know of a quality tall and skinny retention tank? With 15 to 30 gallons I should have 9 to 18 minutes of contact time with the 1.6 gpm feed flow.
Which from what I've grasped should be enough for oxidation purposes but maybe not bacteria killing.

 

[ditttohead]

I will send you a PM, I have several companies that sell our mini contact tanks, 10 and 12" and they help. A static inline mixer would also be beneficial.

 

[Water Pro]

Thanks for your advise guys
.
Bannerman I know that the best option would be to move the iron filter down to the pumphouse but I already have almost everything set up in the house. I don't want the iron and carbon backwashing filters in the pumphouse because I don't have a drain there and made a separate dry pit for them to backwash into close by the house. Also I want things like that close so I can check that they are working properly. I have checked the flow right before the pyrolox filter and with just the well pump going and nothing in the pressure tank I still have the 10gpm. Although I learned from you guys that because my water is cold, 47degrees I might not even need the full 10gpm.

Yes waterpro i have a slight rotten egg odor(sulpher) but it dissipates pretty quick when it sets for a few minutes.

I have never looked into contact tanks but just today while browsing i saw some 15 and 30 gallon ones that are tall and skinny (10",12"). None of them said anything about baffles though. So I don't know if there any good. I saw a clack tank with baffles but that was 21" wide. If I could use one of the 10" or possibly 12" tall skinny ones, I think I can find a way to fit it into the house utility room and put every thing including the chlorine injection there. It will be cramped.
Does anyone know of a quality tall and skinny retention tank? With 15 to 30 gallons I should have 9 to 18 minutes of contact time with the 1.6 gpm feed flow.
Which from what I've grasped should be enough for oxidation purposes but maybe not bacteria killing.

typically 35 minutes of contact time is required when using chlorine, not just for bacteria, but oxidation as well. The way they work is they settle the oxidized iron and manganese to the bottom and have a blow down to periodically empty what's accumulated. the standard size for contact tanks is 120 gallon. the GAC tank just removes the required 2 ppm residual chlorine after retention. peroxide doesn't require much contact time, so a retention tank isn't required, it oxidizes almost on contact, then the pyrolex removes the oxidized Fe/Mn mechanically.

 

[Wolf911]

I first wanted to do peroxide instead of chlorine but read several places that peroxide cannot be used with pyrolox so changed my strategy to chlorine injection. I also read several test papers that said peroxide has little effect on manganese but chlorine does. Was that information not accurate that I read. I would rather use peroxide but thought it would ruin the pyrolox.

 

[Water Pro]

I first wanted to do peroxide instead of chlorine but read several places that peroxide cannot be used with pyrolox so changed my strategy to chlorine injection. I also read several test papers that said peroxide has little effect on manganese but chlorine does. Was that information not accurate that I read. I would rather use peroxide but thought it would ruin the pyrolox.

I should have stated with KL. I have no real world experience with pyrolox. Because you implied there was a space constraint, I was simply stating with H202 you wouldn't need a retention tank and mechanical filtration is the preferred method following oxidation.