Equipment Recommendations

We recently purchased a new home with a well. The water has several issues that need to be corrected. I'm trying to determine what conditioning equipment I need. Here are what I think are the key parameters (the range of values represent tests done at different times by different people).

Hardness 7 - 11
Iron 0.3 - 1.0
pH 7.1 - 7.8
Manganese 0.0 - .04
Hydrogen Sulfide 0.4
TDS 157 - 176

I have had several water conditioning companies come to the house, test the water, and provide quotes. Their recommendations include a water softener plus one of the following: manganese greensand filter, Pyrolox oxidation filter, air induction system + Birm filter, and dual media softener with KDF. The greensand filter apparently needs regular regeneration with potassium permanganate. The KDF was claimed not to need replacement or regeneration. I didn't get much information on the Pyrolox filter.

Do I really need anything more than just a water softener (with maybe a sediment filter) for this water? Are there some softeners that use significantly less water during backwash? Do I need something else to address the iron and sulfur smell? If yes, what are the advantages and disadvantages of manganese greensand, Pyrolox (which I believe is chemically the same as the greensand), Birm, and KDF? I am particularly interested in a solution that is reliable and doesn't require a lot of backwashing. Our well and pump can deliver 8.5 gpm.

I see that some softeners monitor water usage and adjust the regeneration schedule accordingly. Are they reliable?

 

Accurate test results are important.

This is important because the softener for optimum settings must have accurate results.

I would never (again!) deal with a softener and KDF mix. They are not good bed-fellows in the same tank for a number of reasons. I can go into detail if you wish.

Greensand filter using potassium permanganate are a headache and a real babbysitting chore. They may work and then again may not. Your iron is not too high that a softener can't handle (as well as the manganese).

Birm systems need at least 15% dissovled 02 to work properly, thus the air injection system of some type. Venturis can get clogged and need attention. A gas-off tank will be needed also.

You might want to take things in a step by step approach. Get a quality softener with adequate prefilter and see if that doesn't handle most of your current issues. Although softeners don't (won't) handle sulfur problems, there are cases where a softener can improve odors problems. Cross that bridge later.

What were the companies that came over and what did each offer?

Andy Christensen, CWS-II

 

Lindsey/Ecowater proposed an ECR 3500 conditioner and an ETF 2100 filter with manganese greensand media.

Atlas Water Systems suggested a 20" Big Blue prefilter with an Avantapure Logics conditioner with KDF added to the resin bead bed. Noticing that the arsenic test results after the well had just been drilled (Nov 2005) were .013 mg/l, they also suggested a reverse osmosis system. A subsequent water test done in March of this year showed the arsenic to be

 

Prefilters for water systems are generally about 99% sediment in type. I would use a pleated type rather than a string-wound or foam type. These are reusable in most circumstances. A Big Blue (4.5" x 10") will provide adequate flow rate for most residences.

Don't use a GAC as your first filter, but, rather, your last in a series of filters.

Greensand filters use a messy substance called potassium permanganate that needs to be correctly mixed/stirred. Service guys hate working with it. It will do the job but I have seen where they fail after a given period of time and people are tired of replacing them. Usually, shortly after any warranty is up. Odors start to come through and service is required.

Iron levels of 0.3 ppm or less is considered low but softeners can handle much greater amounts, well within your range.

KDF is extremely heavy and needs to be backwashed if it is expected to last for any length of time. The problem is, it is so heavy that normal backwashing re=ates of softener valves is way too inadequate. Thus, it soon solidifies and channels are developed so that water swiftly passes through the media with any contact time.

Once it solidifies, it is virtually impossible to clean out of the tank when replacing is required. A company may state that it doesn't need to be replaced but will refuse to warranty it past the allotted time. Therefore, you will have to pay for it, IF they can get it out. If not, then a whole new system will be required.

I strongly advise against tanks with mixed KDF and softener resins.

If you put in a softener that handles the iron and hardness, and you are still getting sulfur smells in your cold water, then a sulfur system may be required.

There are chlorine pill droppers, chemical feed units and backwashing filters using hydrogen peroxide. I prefer the latter but they are also more expensive.

At 0.4 ppm sulfur, that might be a little too much. A post filter using KDF and/or carbon can be added but needs to be changed occasional. It must be large enough to handle the flow rate and have enough shelf-life so that you are not replacing too often.

Hope this helped,
Andy Christensen, CWS-II

 

Your information and responsiveness have been very helpful indeed. Now that the turkey is pretty much gone, I have some additional questions.

Can either the iron level or sulfur smell be aggravated by lack of use? This house has been unoccupied for two years (since the time it was built). I'm wondering if the sulfur level may decline, for some reason, with regular water usage. It seems like a softener will readily take care of the iron so it's really the sulfur that I'm concerned about.

I found a few references that say that hydrogen sulfide, especially in the presence of iron, can interfere with water softener operation. But they provide no details on what will happen. Can you explain the impact? Considering this, would it make sense to install a sediment pre-filter, follow that with a GAC filter, and then install the softener? If our H2S level is 0.4 and there are just two of us in the house how long could we reasonably expect a GAC filter cartridge to last?

I spoke with the Lindsey people again and they explained that their manganese greensand filter recharges using an aerator built into the tank, not with potassium permanganate. They say this shortens the life of the media but gets rid of the mess and risk of the permanganate. Is that really the case? It sounds appealing since the chemistry of greensand seems to be pretty effective in addressing iron, manganese, and hydrogen sulfide. If there was a less fiddly/more reliable method to utilize greensand that might be appealing.

Also, do you have any experience with catalytic carbon filters? From what I've read if you have enough dissolved oxygen in the water they're relatively simple and reliable. I'm not sure how you determine dissolved oxygen content, however.

Thanks again for all your help.

 

"Can either the iron level or sulfur smell be aggravated by lack of use? This house has been unoccupied for two years (since the time it was built)."

Well, iron might precipitate and form iron deposits on the plumbing, valves might be harder to open or once opened to get them closed again, such as in the drain of a water heater.

But in general, I don't see where long periods of time will do much worse.

As for sulfur gases, they tend to raise to the highest location (upstairs shower heads) and sit there until released. There might be some minor corrosion on pipes but not like low pH. So I wouldn't worry too much there, either.

Running water can either increase or decrease the sulfur in the pipes. If you have trace amounts then it builds up and is very noticeable when the valve is opened but soon dissipates. On the other hand, if sulfur is high, drawing it from the well, full force will make it increase in odor. Sulfur is a tricky contaminant.

“I found a few references that say that hydrogen sulfide, especially in the presence of iron, can interfere with water softener operation.”

I have never found where sulfur interferes with the operations of a softener except to corrode, slowly, some metal fixtures. It normally passes right on through. It can affect an RO, however.

Run greensand without potassium permanganate? Never heard that. What would probably happen is that it will work for a short time, but become exhausted where every a backwash won’t properly clean it and it will need to be rebedded. Thus, it precluded a long timel ine in operation...to his benefit? I wonder who will be doing the rebedding at your cost?

Trying to put a replaceable cartridge to handle sulfur may prove a daunting task and which replacements will become a p.i.t.a. and an alternative will then need to be resolved. Carbon cartridges are nortamally used fro drinking water at lower volumes and less retention time. On a whole house application the water will pass through so quickly that affective sulfur removal will be nominal at best.

Hope this helped a little,
Andy Christensen, CWS-II

 

I asked the Lindsey people about their proposal to use greensand with an aerator at the top of the tank to regenerate the greensand. They say they've been doing this since 1984. It's an appealing concept: the proven ability of greensand to address both iron and sulfur without the mess and risk of potassium permanganate. But then I say to myself, if this works so well why hasn't it become a standard in the water conditioning business? Even if they had patented this idea, patent protection only lasts for 17 years. It's still a confusing situation for me.

One of the companies I spoke with said there's a 50-50 chance that when the iron is removed with a softener that the sulfur smell will also go away. What is your experience with that? Is there some correlation between iron and sulfur? I have read that sulfur can be present in several different chemical forms (sulfides, sulfites, sulfates). I don't know if iron interferes with or enhances the presence of certain forms of sulfur. You're right--sulfur does seem to be a challenging problem.

When you talk about adding a sulfur system if the softener and filter aren't adequate, you mentioned pill droppers, chemical feed units and a backwashing hydrogen peroxide filter. Where are these devices installed? These all sound like oxidizing devices. So does that mean they precipitate out the sulfur as a solid that then needs to be backwashed out?

Are there some water softeners that use significantly less water during the backwash cycle than others? If there are, and they still backwash effectively, I'd certainly be interested in them.

Thanks again for all your help with this.

 

I have noticed a reduction in sulfur smell after the softener, BUT, that should not be the case and would never suggest, let alone guarantee a prospect that.

Yes, sulfur can exist in different forms but it is the gaseous state that causes most concern.

I don't think I ever mentioned pill droppers but that is a recommended method for some companies. Chem-feeders usually use either Cl or H202 followed by a retention tank and backwashing filter. These will aid in both iron and sulfur treatment. Most of these are placed before the softener. Kinetico has an effective sulfur system that follows the softener. And yes, they do precipitate the elements to be backwashed and/or drained.

Some aeriation systems vent the gases as well. Ozonation systems can be very effective but they are costly.

Yes, there are softeners that use as little as 35% of the water during regeneration cycles. Counter-current softeners use less water and salt during these stages. They backwash very effectively and may not interrupt your serive at all.

Andy Christensen, CWS-II