High Iron and Water Softener / Filtration

MFleckJuly 13, 2014

I'm looking for some advice with water filtration and iron removal. I also have manganese, some hardness, and my water is moderately acidic.

I presently have a Watermann softener (with 1 cubic ft of fine mesh resin) and an acid neutralizer. Both units are ~15 years old, and the softener is now completely dead (leaking water at the head due to corrosion).

We've had the water tested in the past (after it went thru treatment) and both units appeared to be doing their job. Iron was removed, water was soft, and pH was raised above 6.5. The existing (now broken) softener was recharging 3-4 times/week.

Since I probably have to replace everything, what would people suggest that I install?

I just had the water tested (pre-treatment), and the results are listed below:

Iron 19.1 mg/l
Manganese 13.3 mg/l
Hardness 101 mg/l (5.9 GPG)
pH 6.05

Bathrooms: 1 and 1/2 (only 1 with a tub/shower)
People: 3 adults
Water usage: ~200 gallons/day

Thanks for any help or advice that you can offer!

This post was edited by MFleck on Sun, Jul 13, 14 at 14:16

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I've made a couple of assumptions:
1. You have a private well.
2. Your iron/manganese is dissolved.

Regardless of whether or not my assumptions are correct, you need a more complete water test from a certified lab. You need to know: pH, TDS, sulfur compounds (sulfates, sulfides), ferric iron, ferrous iron, manganese, particulates, bacteria, anything else recommended by your state/county for your area's water.

If these assumptions are correct, here is what I would do:

  1. Take a look at the well. How deep is it? Could you drill deeper to find better water? If not, then:

  2. Acid neutralizer using soda ash. You pH is so low that a typical calcite neutralizer will add significant hardness to your water and you don't need any more problems. You ought to raise pH a bit above 7 to protect your downstream plumbing and make iron/manganese removal more reasonable.

  3. Iron removal system. There are a number of options to remove iron/manganese. I will post some additional information separately.

  4. Softener, possibly. You may find that once the other problems are taken care of, you don't feel the need for a softener. I would still want a softener with 5.9 gpg hardness, but not everyone does.

    Bookmark   July 13, 2014 at 8:37PM
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Iron/Manganese removal:

  1. Softener: A softener with specialty resin is capable of removing dissolved iron, up to 7 ppm (mg/L) but asking a softener to remove iron at those upper limits is really pushing it so I would not recommend this method. In addition, a softener will become fouled with particulate iron, which you have at least sporadically. Since your iron and manganese levels are so high a softener is a terrible option for you.

  2. Oxidation/Filtration: An oxidizer such as ozone, air, or chlorine may be used to react with the iron and force it to become particulate iron that can then be removed via filtration. A typical setup would involve the oxidizing unit, a holding tank, then a media filter. This type of system works quite well, but takes some expertise in sizing - you would want a water treatment pro that you trust to help you with this option.

  3. Oxidizing filtration media: This type of treatment consists of a sealed tank filled with one of several media. Water passes through and is oxidized and filtered by the media. These are relatively easy to operate and what I would recommend for the average homeowner. There are several different media that can be used:

  • manganese greensand: water runs through for treatment. The media must be regenerated with potassium permanganate. Care must be taken with dealing with potassium permanganate as it readily dies organic material, such as your skin, a purple-brown color. Some people are quite comfortable dealing with the chemical; others are not.

  • Synthetic greensand: This is essentially the same as option (a) but consists of a coating of greensand on a silica sand core so does not require as much backwash flow. Service flow rate is 2 - 5 gpm/sqft. Backwash flow rate is 12 gpm/sqft.

  • birm: This media acts as a catalyst to force oxidation of iron. While it does not need to be regenerated, it does need fairly high dissolved oxygen in the water. If your water does not have adequate dissolved oxygen (and it probably doesn't since it is well water), air injection would be necessary prior to the birm. Additionally, birm requires a minimum pH of 6.8.. Service flow rate is 3.5 - 5.0 gpm per sqft. Backwash flow rate is 11 - 20 gpm, depending upon water temperatures and desired bed expansion.

  • pyrolox: an ore that oxidizes then filters the iron out. It does not need regeneration, but needs to be backwashed (to rinse out the iron) at a high rate. pH range is 6.5 - 9.0. This type of filter works very well, but backwash is critical. Service flow rate is 5 gpm/sqft. Backwash is 25-30 gpm/sqft. Backwash daily.

  • Terminox: Similar to Pyrolox, but a proprietary formula . It does not require as much backwash flow rate and is more resistance to a low pH. The particulars are only available from the company that sells it. Backwash daily.

  • Filox: Also similar to Pyrolox. pH range 5.0 - 9.0. Backwash flow 12-15 gpm/sqft. Service flow 6 gpm/sqft. It must be backwashed daily.

    Bookmark   July 13, 2014 at 8:40PM
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Thanks aliceinwonderland_id.

Yes, it's a drilled well -- I'm not sure the exact depth, but I have neighbors with high iron (seems to be an issue in the area).

It's a rental property, so I want to find a good solution that isn't super expensive and isn't too complicated to maintain.

Does the synthetic greensand required regeneration with potassium permanganate? I'm not sure that I want tenants handling potassium permanganate.

From what you listed, I'm thinking a birm filter with air injection (after raising the pH first). I'd rather have fewer tanks, minimum (if any) regeneration cycles), and limited backwashing.

Thanks again. My well guy is contacting a couple of water treatment companies.

    Bookmark   July 13, 2014 at 9:08PM
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I should add that the iron definitely comes out of suspension once it oxidizes. We once inadvertently filled our hot tub with unfiltered water. When we added the oxidizing chemicals to the hot tub, the water turned muddy red.

    Bookmark   July 13, 2014 at 9:28PM
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