Double Trouble (Iron and Acid)

[deltasmith]

I have two wells with two different sets of problems and I'm hoping someone can suggest some ideas on how to solve them.

Both wells are approximately 300 feet deep and use submersible pumps. Well #1 has very acidic water and a recovery rate of just 0.5 GPM. Well #2 has massive iron (mostly disolved) and a slightly better recovery rate of 1.5 GPM. House is sized for a family of four though it's just my wife and I most of the time, except when we have guests. We have about a half acre of lawn and garden that we need to water during the dry months (and well #1 is not especially reliable during the dry months, and we also tend to have visitors during those same months, which is why I invested in well #2).

Highlights of test results from Well #1
Hardness 49 mg/L
Iron 0.15 mg/L
Magnesium 2.4 mg/L
Manganese 1.5 mg/L
pH 5.2


And from Well #2
Hardness 110 mg/L
Iron 20 mg/L
Magnesium 4.5 mg/L
Manganese 0.82 mg/L
pH 6.2


But a footnote is that the 20 mg/L Iron for well #2 was reported by the state lab that I recently mailed a sample to, yet a few weeks ago I had a water treament technician in my yard who took the samples on the spot and he only came out with 8.2 mg/L iron. (The water treatment guy wasn't a salesman and didn't stand to make a commission, though certainly his company stands to profit if I do business with them). I'm trying to figure out which test to believe - the one done within a few minutes after taking the sample or the one done 24 hours later after all the disolved iron had presumably reacted with the air in the sample bottle.

Assuming I need a system that can handle 20 mg/L Iron, I'm wondering about systems that are rated for something less than that. Say a system was rated for 15 mg/L: can I assume that if I put a decent water softener downstream of that that it can pull out the remaining 5 mg/L? Or will the 20 mg/L just totally foul the iron filter that's only rated for 15 and cause it to plug up or lose filtering effectiveness?

I originally thought to construct one system that I could run both wells through, but now I'm not so sure. It seems that most iron treatement systems don't like low pH and most pH treatment systems don't like high iron, so I'm not sure which treatment mechanism should come first. Maybe it would be simpler if I just focused on well #2 (has higher recovery) and forget about well #1.

If anyone has an idea about what kind of a system I can build to treat one or both wells, I'd appreciate the information.

Thanks

[Gary Slusser]

Both wells have acidic water that should be treated.

IMO the best way to do that is with a backwashed acid neutralizing filter. They use a sacrificial mineral that adds hardness to the water.

You don't want to treat irrigation water because the equipment would have to be very large depending on how many gpm and total gallons used. But with your iron content you can;'t use the water without rust stains all over everything.

BTW, labs sell water tests, so the idea that a water treatment dealer you call to come out and look at your water quality problems that you already are aware of or wouldn't be calling him out, he has no need to lie to you. AND, if he proposes equipment and you then buy equipment from him and it does not work, he'll probably make it right on his own or, you can sue him. What is your recourse with a lab that lies or otherwise screws up your analysis? You did pay them before they did anything buy say Hi, right?

And how would you know things were screwed up unless someone, like the water treatment guy (that really should do his own testing instead of relying on a lab's young couldn't care less about accuracy trainees), tested the same water? And as we see here, there is a huge unexplained difference in your iron content.

So what are you going to do now? Which result do I use to advise you about? My advice, sort it out and post the new data.

[deltasmith]

I've done a lot of thinking about this and I'm coming out with the impression that both test results were probably reasonably accurate for the sample of water that was being analyzed.

I tend to trust the state health department's test results in terms of reliability. I can see that the same people who tested well #1 a few years ago signed off on the tests that I recently submitted for both wells this year. I can see that the iron results for well #1 are reasonably consistent with what they have been in the past (although the acidity in well #1 seems to be getting progressively worse). So I think I can rule out concerns about inexperienced interns, etc.

Well #2 had an even worse iron problem until about six weeks ago (it was literally off the scale - the local water treatment companies left the yard shaking their heads and saying things like: our best filter combination can not guarantee that you won't get some amount of iron staining with this water). We discovered this year that the well casing did not have a good seal and a lot of surface water was leaking in around the casing. I paid to install a new seal and that seems to have mitigated the iron content somewhat. However, the well is three years old and so it has had that much time to accumlate ferric iron deposits on the sides of the well. When I run the garden hose, I see reasonably clear water for an extended period, but occasionally it's punctuated by a cloud of rusty colored water that takes maybe five minutes to clear up.

So I'm thinking that if I was using the well every day, I'd probably get most of my water with around 8 ppm iron content, but that there would be periods when the well would serve up the 20 ppm iron content (or maybe even worse) that the state lab saw.

Not sure if that means I can get away with a quasi-chemical-free greensand system that doesn't need a chemical backwash but is only rated for 10 ppm, or if I need to go with an alternate system that supposedely can handle up to 20 ppm.

I see that RainDance has a system (Iron Eater) that they claim can handle 20 ppm and it removes not only rust, but also hardness. Apparently they use a potassium backwash instead of a salt backwash. Does anyone have experience with this kind of system?