Removing Iron and Manganese from irrigation well water

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Chris Bradburry

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Hello
Been reading the various threads on removing iron from well water, and getting ready to purchase a system. Lots of opinions out there however, so I would appreciate it if anyone had some sound advice. Here is my setup and recent water test.

Well is only for irrigation and my only concern is cosmetic (staining). We have severe iron staining (and likely manganese as well).
6 zones, each with 5 or 6 3GPM rotors, for a total max use of 18GPM. Sprinklers run every other day or so for 30-45 minutes/zone.
I tested the well output via the pressure tank draw down test and I get 20.5 GPM from the well.
Here is a recent test from a local city water lab:
pH: 6.6
Hardness: 263
TDS: 518
Iron: 1.78 mg/L
Manganese: 1.11 mg/L

No evidence that I have iron bacteria - my pipes are crystal clear on the inside.

Local water company has been recommending a Filox setup, 2 smaller units in parallel which would give me an adequate flow rate and still be able to be backwashed appropriately within the constraints of my well output. He feels that Filox does better with the Manganese. Honestly I had been leaning towards a Katalox Light setup due to the lower backwashing requirements. I would still expect to need at least a dual setup in parallel however based off my water use requirements.

Any thoughts on a setup?

The other variables (which seem to be all over the place) is the need for an oxidizer of some type upstream from the filters as well as the need for an injector of some type to raise the pH for better manganese removal. My local water company seems to be more of the "try it and see" mindset, but I prefer to get everything I'll likely need up front.

Thank you for your consideration.
Chris
 

Reach4

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One strategy could be to only treat the water to the spray heads that are near the house and concrete. Let the part away from stuff that stains use the raw well water.

I know that might be more trouble than it's worth.
 

Chris Bradburry

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One strategy could be to only treat the water to the spray heads that are near the house and concrete. Let the part away from stuff that stains use the raw well water.

I know that might be more trouble than it's worth.

More trouble than its worth. Would require a lot of replumbing of the irrigation system.

From what I read, others on here have been successful to eliminate the staining. Just looking for opinions on the best approach with regards to equipment needs.
Chris
 

Chris Bradburry

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Here are my calculations with the Katalox. Data is from their product brochure.
1.78 mg/L Iron x 3.8 L/Gal x 5000 Gal (estimated daily irrigation use) = 33,820 mg / Iron / Day needing removed
1.11 mg/L Manganese x 3.8 L/Gal x 5000 Gal = 21,090 mg / Manganese / Day needing removed

33,820 mg/Iron/Day x 85,000 mg Iron Removed/Cubic Ft Katalox = .39788 Cubic feet of Katalox media required for Iron removal
21,090 mg/Manganese/Day x 42,500 mg Manganese Removed/Cubic Ft Katalox = .4962 Cubic feet of Katalox media required for Mananese

Total Katalox = .39788+.4962 = .8941 Cubic Feet

Spent the whole day trying to calculate numbers with the Katalox. If I use the calculations provided in the linked thread above, I really don't need a lot of Katalox media to do the job. I calculate just under a cubic foot. My limiting step then becomes GPM. I need a filter (or parallel filterS) that will get me 18 GPM flow. I will end up with much more media than I need. My problem is I have found 2 separate brochures from Katalox, one I suspect is older, and they both give different flow rates. (What I think to be the newer brochure has much lower rates, perhaps due to time and experience with the media by the manufacturer??).
My local water shop keeps coming back to Filox, as the flow rate and backwash requirements are very close. I am leaning toward 2 parallel 12x52 Vortech tanks with 2 cubic feet of media each. If I believe the manufacturers data, should give me a flow rate of 11.5 GPM (23 GPM running parallel) with an individual back flow rate of 11-17 GPM depending on water temp. Water is cold, so would expect the lower end. Vortech tank should also help with this.


Any thoughts?
Chris
 

Chris Bradburry

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Here is a link to the manufactures brochure directly from their website. I assume this to be newer, correct info.
https://www.watchwater.de/wp-content/uploads/2019/01/KL_Brochure_NEW_ver_1.1.pdf
Here is a link to the manufacturers brochure from Pure Water Products:
https://www.purewaterproducts.com/img/docs/manuals/Katalox-Light.pdf

The removal capacities are the same, but the flow rates are significantly lower in the brochure direct from the manufacturer. I need to get to 18gpm to supply my irrigation system, but only have 20gpm capacity from my well.
Chris
 

ditttohead

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In general KL and most iron reducing medias need about 3 GPM per ft3. The problem with your water is the low pH. Ignore the literature, most of these brochures are written assuming perfect water conditions. In the real world we find that these specifications are greatly exaggerated. Filox/Pyrolox are great medias but their backwash requirement is excessive. In general I would estimate the backwash rate of pyrolox/filox to be about 20+ GPM for a 12" tank. This has always been its downfall. The lack of backwashing is very damaging to this media. KL is typically backwashed at about half that of Pyrolox.

An oxidant will likely be needed for adequate reduction. This can be as simple as a hydrogen peroxide injection system. You could try running the KL system without it for a while to see what the results are but my guess is, at the high flow rate and low pH, you will benefit greatly from h2o2 injection.
 
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Chris Bradburry

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Just an update for anyone who searches the forum later, I ended up going with a tri-plex setup with 3 14x65 units with Fleck 2750 heads. I don’t have testing done yet, but preliminary visual results seem very positive. I took a water sample from the filter water and left it out overnight, it was crystal clear in the morning where as previously it would have turned orange in just an hour or so. Overall happiness far. I will post water testing results when I have them.

My one question is that the units came set up with a 10 GPM DLFC button. The Katalox brochure indicates a need for 16 GPM backwash for this sized tank. I would assume this needs to be exchanged. The Fleck parts manual shows a 15 or 20 GPM button as being available. Which should I use?

Thank you
Chris
 

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Reach4

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I think you want to aim at about 30 to 35% bed expansion, but I am not sure of the best target. The amount of expansion is affected by the backwash water temperature. I am guessing that somewhere around 17 gpm might be good. Texas is a big state, in case nobody pointed that out to you in the last 2 minutes, but even if I knew whether you were near Houston or Amarillo, I would not know the ground water temperature anyway. Ten gpm is too low for sure. So anyway, if the choices are 15 or 20, then estimate or try to measure.

You might be pump-limited anyway, but the DLFC would control the burst of pressure before the pressure tank gets emptied.

I measured my water temperature by one of those inexpensive thermometers with a probe that can record the minimum temperature. I placed the probe next to a copper pipe going into my filter, and wrapped around with some cloth for insulation.


img_kl14.PNG
 

Chris Bradburry

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Reach
Thank you for the chart. I measured my water temp at the inlet and got just a hair less than 22c. Based off your chart, I need just north of 14-16.8 GPM for 30-35% expansion. My pump will supply 20 GPM by the drawdown test. Still not sure if the 15 or 20 DLFC button would be more appropriate, but leaning more towards the 20.
Chris
 

ditttohead

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Get both buttons. I prefer the higher backwash rates if you have the water available. Just watch the drain to make sure you don't lose media to the drain during backwash.

2750's? :) 1980 just called.
 

Chris Bradburry

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Well after working well (although infrequently over the winter) my beautiful clear water has turned orange again!!!

I went from over 3ppm to 0.1ppm Iron initially after the installation of the system above. Clearly (no pun intended) not in that range any longer.
About ready to jump off the roof....

I think I didn't backwash well enough. Ended up using a 15 GPM DLFC which is likely (apparently) inadequate for my water temp - 22c as above. Was backwashing every 6 days for 16 minutes with the well only being used for irrigation once a week over the winter. Plan was to increase the frequency as water demands increased this Spring. When I realized I had a problem I changed the frequency to every 3 days and manually ran 2 or 3 backwash cycles for each of my 3 tanks. Did not seem to help based off my observation of letting a sample sit out for a few hours - slowly turning orange.

My pump will support 21 GPM. I will swap the DLFC out for a 20 GPM unit. Change the backwash to every other day? Longer duration?

Can my Katalox media be salvaged?

Appreciate any help or suggestions.
Chris Bradburry
 

LLigetfa

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I did not read the entire thread but did you end up using an oxidant? If so the line from after the oxidant injection could be getting constricted with iron, reducing the backwash rate. I use air injection and have to purge out my lines periodically.
 

Chris Bradburry

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I did not end up needing to use an oxidizer. The filter media did an incredible job at removing the iron initially (both observationally as well as by testing). It has just failed over a short time.
Chris
 

Bannerman

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This quote from Ditttohead in post #8
An oxidant will likely be needed for adequate reduction. This can be as simple as a hydrogen peroxide injection system. You could try running the KL system without it for a while to see what the results are but my guess is, at the high flow rate and low pH, you will benefit greatly from h2o2 injection.


I did not end up needing to use an oxidizer.
You may wish to reconsider if a drain flow rate restriction as LLigetfa mentioned, is not the issue.
 
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Chris Bradburry

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I am by no means any type of expert and appreciate any input, but I am not sure about the addition of an oxidation agent solving my problem.

In my mind, I would think that the Katalox media as supplied would either adequately remove my iron, or not, without the addition of an oxidation agent. In my installation it certainly did and was wonderful for some time.

Had it not been successful in completely eliminating my iron problem initially, I would think at that time it would’ve been a good option to consider the addition of an oxidizer.

Given that it adequately removed my iron initially, how would the addition of an oxidizer at this point help me with my media not fouling?

thank you
Chris
 

ditttohead

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I would recommend adding chlorine ahead of the KL systems at least temporarily. This should help tremendously. You could simply add the chlorine to the well and run it through the beds.
 

Chris Bradburry

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Fair enough.
Never put chlorine in the well. Technique? Dump a few gallons of bleach? Chlorine pool tablets?
Dump them in and then run a regen, or let the chlorine sit a bit?
Do you think this will help clean the bed fouling as well?


Chris
 
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