Battles with manganese

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WellOff

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I am in north Snohomish County (WA). About a year and a half ago I rehabbed a 38' deep well. According to well logs the well was constructed in 1994. At some point, I narrow it down to maybe 2004, the well was taken out of commission. Reasons/history unknown as it all disappeared with the death of the owner. I suspect that the multiple issues were too much for the previous owner (the property was a rental, so he bypassed the headaches and plumbed in a water feed from a spring from nearly 1/3 mile away). The well log says it tested at 30gpm; I have no reason to doubt that, or that it's diminished to any degree (I pumped at 10gpm for a solid 24 hrs and no hint of running dry- in this area it's nearly impossible to run out of water). I had initial lab tests done and, except for some e-coli and coliform, the e-coli was likely from critters falling into the OPEN casing (I saw claws get ejected when flushing the casing), there was no inorganic concerns, only nuisance issues/elements- iron, 1.97 mg/L, manganese 0.118 mg/L and IRB (Iron Reducing Bacteria): turbidity was measured to be 4.01 NTU. pH was originally tested to be 7.10 and has, over the course of nearly two years of testing, managed to stay just about right around that, tending toward 7.0 (6.91 to 6.99). Hardness is ranging around 70 mg/L (last test showed untreated at 73.2 and treated/filtered at 71.6).

My issue is that I cannot get manganese levels down to tolerable levels*. Actually, the system seems to have ZERO affect on my manganese levels EXCEPT to INCREASE(?) them! My last test, back in August, showed my raw water manganese levels at 0.076 mg/L and my treated water manganese levels at 0.097 mg/L. How could this happen? I'd suspect that maybe the carbon is fouled, but iron is testing to be "ND," and all else seems fine. I had a period of time in which I had the water meter in the incorrect position in the system which wouldn't account for treating the water as used during backwashing: I was struggling with leaks and moved it; I have long since moved it back (and gotten the leaks under control).

* I have lingering metallic aftertaste, especially with coffee and teas. I'd say that the 0.097 mg/L level was acceptable (I'd rate the water quality at nearly 9.0 on a scale of 1 to 10), though the thought that the system was doing nothing for the manganese was NOT acceptable. Right now the levels seem higher (taste is worse), though this is subjective (no lab test for current).

I've never liked how the water tastes following backwashing of the carbon filter. It seems to settle down after a few days. I have messed around with the frequency of the backwashes from every three days to once every two weeks (mostly chasing the manganese issue), with little difference being detected other than that off-taste post backwashing (I can't really describe it, but in a way it seems like it might be elevated manganese).

I spent quite a bit of time researching and consulting with water "experts." (I've run across people [a local office of a national firm] in the business that didn't even know what "IRB" was! the guy there told me I could get by with only a water softener!) The folks that I purchased my components from were pretty certain that the components would do the job, and by all accounts I was able to back up their claims. I did a lot of follow-up with them on the manganese issue and they pretty much threw their arms up stating that they'd swap out the carbon media and I could go with sodium hypochlorite (which I thought horribly illogical given that H2O2 is a stronger oxidant).

My well, treatment and filtration systems is as follows:
- 35' finished iron cased well bore with 5' of mesh (I flushed and scrubbed)
- 1/2hp submersible pump
- 80(? I'm not remembering at the moment- just note that it's large) gallon pressure tank
- Lakos spin-down filter post pressure tank (can't recall mesh size, but I'm not seeing it clog up)
- Stenner pump metering Hydrogen peroxide at roughly an 2ppm rate (injection controlled via water meter)
- 40 gallon contact tank (my daily household usage rate is roughly 70 to 75 gallons) - H2O2 residual testing around 1.6ppm (I've got it a bit high, but have had it as low as around .2ppm, which is supposed to be the target)
- Carbon filter, Centuar Carbon - 1.5 cf (tank has Fleck 7000sxt valve)
- Big Blue filter using dual-density 1 micron cartridge

All bacterilogical tests have tested negative for e-coli and fecal coliform. Raw water samples, however, HAVE shown the presence of fecal coliform. My system seems to be doing its job in this regard, as well as in dealing with the IRB and iron.

I flush the contact tank and change the final filter. Tests for H2O2 residual show that the treatment has been fine.

Lastly, I wonder about the backwashing cycle consuming roughly 110 gallons of water, that this essentially overruns the contact tank's functioning (only 40 gallons). I repeatedly tried asking the vendor about this but they avoided answering it: despite all my efforts to provide feedback and info to them they have decided to ignore me.
 
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Reach4

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I have a Centaur Carbon media backwashing filter that is good for sulfur and iron for me. I have not seen Centaur Carbon recommended for Manganese.
 

WellOff

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"I have not seen Centaur Carbon recommended for Manganese."

Well, you're "looking" at someone who quite specifically discussed this and had it recommended. My observations would support your recommendation: I would NOT recommend it either. I would really like find some sort of technical documentation that backs this up so that I can send it to the folks who sold me my system.
 

WellOff

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The vendor's last reply to me was:

"Sounds like for this water you will need some type of manganese removal media. For some reason the manganese is not oxidizing perfectly to a state that can be filtered out."

From the very start I had given them lab result numbers. Never was there a hint that what they had recommended wouldn't work.

Here is what was then offered up:

"Switch to chlorine and rebed the carbon filter with Mang-OX manganese dioxide filter media. This lasts for many years and does not require frequent changes. " [after being sold on H2O2 I was NOT happy to hear this]

or

"Keep the peroxide and install an additional iron filter (using mangox, also known as pro-ox or filox) after the carbon filter. The mangox media cannot have any residual of peroxide going into it, but it does not require the manganese to be oxidized, it removes the dissolved manganese very well, as long as there is some dissolved oxygen in the water (which would be from the peroxide) or there is a chlorine feed." [Does this seem to contradict itself, that H2O2 isn't wanted but that the DO from it is? Also, I have no room for any additional equipment.]

They also offered a refund.
 

Reach4

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They also offered a refund.
Nice.

See https://terrylove.com/forums/index.php?threads/help-hard-water-manganese-and-iron.55192/#post-404286

I suspect that some will have a suggestion of alternate media. You did not mention H2S or SRB. It does not get tested for in most water tests, but your nose can maybe pick up on it in the raw water. Or maybe you had the water for a while before you new filtration system was put in. That would play a factor in choice of media too.
 

ditttohead

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Manganese removal can be difficult as you are finding out. The carbon does not "remove" the manganese, the principal is that the manganese oxidizes into a solid form and is physically removed as a sediment. Carbon can act as a good physical filter thereby catching the oxidized iron and manganese and removing residual peroxide. If it is getting properly oxidized, it should be removed. Have you tried increasing your dosing for a little while to see what happens? Contact time, water temperature, competing elements, pH etc. all come into play.
 

_John_

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IMO, other than maybe suggesting a lighter media like Katalox Light the vendor is doing what I'd suggest too.

I know this is a different market (DIYers) with people more willing to tinker with their setup than some of our customers (I work for a well company), but I'm not the fan of carbon that many dealers seem to be. We use it, but not as our go to.

Your bacteria issue forces the oxidant, and though peroxide is stronger, bleach ahead of a katalox bed would be my recommendation for a go to step. I've seen many mangox setups take care of those levels (when bacteria was not a problem like you have) I have a mangox filter on my water, but since we started using katalox I've not come across a job where I'd really recommend it first.

You may not care for the chlorine residual in your water, but at least it's cheaper and easier to get.

You could add a dilute oxidant injection at backwash if you were worried about the backwash getting ahead of your contact tank.

Oh and to answer your question about the second vendor suggestion, mangox/katalox needs oxygen or some oxidant to oxidize iron/sulfur/Mn on its surface, and peroxide injection will add oxygen to the water before getting to it if it were after your other carbon filter. The reason peroxide is not adviced before mangox is due to risk of adding Mn to the water due to damage to the media. I admit that I myself need to look into that more as spec sheets for Katalox (MnO2 coated media) list dosing recommendations for bleach/peroxide/pot perm (in the absence of adequate DO) on their spec sheet for the media. I'm not sure why it's apparently ok for katalox and not for mangox myself. High H2S in particular can require a good amount of oxidant to control.
 
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WellOff

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Reach4, no, I never tested for SRB. I was going to, but since I already had tested for IRB (as my research suggested was my primary issue- and it is) and therefore needed treatment for bacteria, I figured it unnecessary: I had fairly lengthy back-and-forth with the lab on whether such a test would be of value to me- I probably drove them nuts over this one!:D Lab tests, however, were clearly telling me that I had an iron issue. Sulfur odors don't seem to exist: I get the fishy smell as associated with IRB.

dittohead, yes, my understanding was that H2O2 was giving me the best oxidization, which I needed. I figured that physical filtering of the Mn would be dealt with just like with Fe. I was encouraged to try and crank up the dosing of the H2O2, which I did, but that didn't seem to make any difference: based on Stenner's info I need an injection of about 1.2ppm or so; the difficult measure is how much is required for dealing with the IRB. My understanding is that the true test/target is based on H2O2 residual, post contact tank, and that that should be roughly .2ppm to .4ppm. I initially calculated for this value (and hit it right out of the gate), but have cranked it up to as high as 2ppm (maybe a bit higher; the vendor also suggested this): it's now been left at around 1.6ppm, though I suspect that this isn't getting me anything over the .2ppm-.4ppm range. I didn't, however, crank it up to the point where I could tell that I was getting H2O2 out my faucets (as recommended by the vendor). That said, I have tested at the faucet and am getting about .2ppm: right on the bottom range for detection- using Hatch.

_John_, I fully appreciate the value of chlorine. In my case the big driving factor (again, this was my call) was over the fact that I have a shallow well and tannins (levels are low, but, I suspected, they'd likely fluctuate during the course of the year and I wasn't going to monitor/test for a year to know for sure). With regard to chlorine being cheaper, the dosing levels is so low as to make it a non-issue: for the first year of operation I used approximately .8 gallons of H2O2 (and that's with a lot of testing and ramped up/over dosing), which at roughly $15/gal works out to $1/mo. And with regard to the issue of availability, I struggled over that- sigh, tradeoffs...

"You could add a dilute oxidant injection at backwash if you were worried about the backwash getting ahead of your contact tank."

I'm not comprehending this (I'm pleading brain-fart on this):confused: All water is treated. The contact tank is to ensure that the bacteria (IRB as well as coliform) is broken down. I was told that I needed a 20 minute contact time for this. Clearly, with a 40 gallon contact tank and a fairly rapid demand for 110 gallons for the backwashing there's water running into the carbon filter that's not getting that contact time. In my mind I struggle with what could be happening inside the carbon media with regard to seeing un-oxidized Fe and Mn (more so Fe given the IRB) and live bacteria while it, the carbon media, is neutralizing the H2O2 (which is supposed to be working on the IRB). It's my understanding that you don't want bacteria in your carbon, is that right? To add to this, I have a need to periodically shock my distribution lines due to odors starting to occur; not sure whether this is just to be expected or whether this is the fallout from this catch-22 with the carbon and the backwashing.

What makes some of this hard for me is that I cannot really say that I know what Mn tastes like :eek: I'm pretty much guessing that it's Mn that's the issue, but it's an educated guess (with lab test results suggesting that it's likely Mn).

One other thing that has puzzled me is that my water will taste dry from time to time. This seems, though I would have to see if I can correlate this with what I have documented, to closely follow backwashings. My research on this comes up blank.

For sure, all these endeavors have made me become quite fascinated with water.:) I appreciate everyone for taking their time to consult/discuss my issues here.
 

_John_

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You can add a small tank with oxidant similar to a brine tank with (usually fairly dilute) oxidant that you use during backwashes/regens. Usually carbons don't need that or use that strategy.

Mainly an "if you use mangox thing" as that strategy is employed mainly with those type medias with problem waters.
 
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WellOff

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You can add a small tank with oxidant similar to a brine tank with (usually fairly dilute) oxidant that you use during backwashes/regens. Usually carbons don't need that or use that strategy.

Mainly an "if you use mangox thing" as that strategy is employed mainly with those type medias with problem waters.

Oh. OK, I think I get it. But... <scratching head> the backwash cycle is consuming 110 gallons of water (always seemed pretty high to me- I have measured/monitored it on a couple different occasions and that's about what it is). What's the water consumption like for backwash/regen for MangOx? It all seems like a chicken-and-egg thing to me.
 

Reach4

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I was encouraged to try and crank up the dosing of the H2O2, which I did, but that didn't seem to make any difference: based on Stenner's info I need an injection of about 1.2ppm or so; the difficult measure is how much is required for dealing with the IRB. My understanding is that the true test/target is based on H2O2 residual, post contact tank, and that that should be roughly .2ppm to .4ppm. I initially calculated for this value (and hit it right out of the gate), but have cranked it up to as high as 2ppm (maybe a bit higher; the vendor also suggested this): it's now been left at around 1.6ppm, though I suspect that this isn't getting me anything over the .2ppm-.4ppm range. I didn't, however, crank it up to the point where I could tell that I was getting H2O2 out my faucets (as recommended by the vendor). That said, I have tested at the faucet and am getting about .2ppm: right on the bottom range for detection- using Hatch.

_John_, I fully appreciate the value of chlorine. In my case the big driving factor (again, this was my call) was over the fact that I have a shallow well and tannins (levels are low, but, I suspected, they'd likely fluctuate during the course of the year and I wasn't going to monitor/test for a year to know for sure). With regard to chlorine being cheaper, the dosing levels is so low as to make it a non-issue: for the first year of operation I used approximately .8 gallons of H2O2 (and that's with a lot of testing and ramped up/over dosing), which at roughly $15/gal works out to $1/mo. And with regard to the issue of availability, I struggled over that- sigh, tradeoffs...

I would think that the test PPM would be the percent of H2O2 in the water. When Stenner refers to PPM, I would think it is the amount of treatment solution to put into the water. It seems to me that if the H2O2 liquid that you buy is 10%, that the amount of H2O2 out of the mixer would be 10% of what the pump was sent for.

I don't know the percent strength of the hydrogen peroxide that you buy. Maybe you are using a table that accounts for that.

One other thing that has puzzled me is that my water will taste dry from time to time.

I am not familiar with the term "dry" being to describe water. I have never read up on H2O2 disinfection. I do wonder what the duration of your backwash is. 110 gallons does not seem surprising if the backwash is 20 minutes long.

My Centaur Carbon filter uses a bleach solution only during the backwash.

I agree that your presence of tannin implies that disinfecting your water continually is warranted. Otherwise I would have wondered if a better well sanitizing would have been sufficient to eliminate the IRB and SRB.
 

WellOff

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I would think that the test PPM would be the percent of H2O2 in the water. When Stenner refers to PPM, I would think it is the amount of treatment solution to put into the water. It seems to me that if the H2O2 liquid that you buy is 10%, that the amount of H2O2 out of the mixer would be 10% of what the pump was sent for.

I don't know the percent strength of the hydrogen peroxide that you buy. Maybe you are using a table that accounts for that.



I am not familiar with the term "dry" being to describe water. I have never read up on H2O2 disinfection. I do wonder what the duration of your backwash is. 110 gallons does not seem surprising if the backwash is 20 minutes long.

My Centaur Carbon filter uses a bleach solution only during the backwash.

I agree that your presence of tannin implies that disinfecting your water continually is warranted. Otherwise I would have wondered if a better well sanitizing would have been sufficient to eliminate the IRB and SRB.

I have all the guidelines from Stenner on dialing things in (based on demands of the Fe and Mn levels). As mentioned, the definitive means for establishing that you have things set correctly is that you meet the demand plus a little left over to ensure, which is that you have a residual of .2ppm to .4ppm of H2O2 post contact-tank.

20 minute backwash sounds right. I think that it does a couple of passes. I have no concerns over how much is used or for dumping it (I send it out in to a ditch); the real concern is whether I'm fouling the carbon by introducing water that hasn't have ample contact time.

I flushed the well with 450 gallons of pH adjusted solution. Professionals have access to chemicals that mere mortals don't have access to. With what mortals like myself have access to is pretty much bleach. I consulted with someone that figured out how to properly adjust the pH of a bleach solution and I went with that: suffice it to say this kind of thing isn't really published because people can run into trouble- I was doing it with plenty of ventilation (all mixing and storage of solution was outside of my pump house). On the end I came to the conclusion that the standard recommendations for shocking as provided by most county health departments is bogus: it's no wonder why folks end up repeatedly having to shock; I suspect this is also why professionals end up being called in; however, though likely more effective I still don't believe that the odds are good for eradicating IRB/SRB if it's in the aquifer.

The reality is that IRB usually cannot be gotten rid of permanently. While one can introduce IRB/SRB into an otherwise IRB/SRB-free well, in most cases the IRB/SRB is in the well and isn't going to go away. Again, I'd researched this to the ends of the earth: had hopes up that some folks doing work in Africa had figured out how to eradicate it, but never did find any follow up to demonstrate that.

The "dry" taste that I experience might be carbon and or Mn. It varies and "seems" to be more likely to be experienced following a backwashing of the carbon filter. Think of drinking water and then feeling like your tongue didn't get any water. It's like a dry tingling? Anyway, it may or may not be part of my puzzle. I think that if I can cut the levels of manganese in half (down closer to the 0.050/ppm) that that will have an affect.
 

Reach4

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For shocking I like this procedure: http://www.moravecwaterwells.com/disin_test.htm

Good for the DIY if you can get some high-range chlorine detection test paper and some pH test strips of the right range. It takes time. I gave it more time than the procedure says. I could not drop chlorine pellets to get chlorine to the bottom of the well, because I have a "4 inch" pump (3.75 actually) in a 4-inch casing. So I let my water circulate, via a garden hose, much longer for the purpose of getting chlorine presence at the bottom of the hole-- over 24 hours. I hope I succeeded. If you have a 5 inch casing, I suggest that you get the pellets made for the purpose. For the saved "flooding volume" water, I used a garbage can line with a clean "yard waste" bag. I used a piece of 1/2 inch vinyl tubing to do the transfer into the well, to make a siphon line. I sanitized the tubing before using.

Regarding flushing, my Centaur Carbon filter uses raw well water for the backflush, which is done every 3 days.

Regarding settings, I don't know how the test would be at the limit of its detection range. It was suggested that you increase the dose. As you pointed out, the expense is small for you. Come to think of it, $1 per month seems very low. That would not buy a gallon of chlorine bleach.
 
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WellOff

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For shocking I like this procedure: http://www.moravecwaterwells.com/disin_test.htm

Good for the DIY if you can get some high-range chlorine detection test paper and some pH test strips of the right range. It takes time. I gave it more time than the procedure says. I could not drop chlorine pellets to get chlorine to the bottom of the well, because I have a "4 inch" pump (3.75 actually) in a 4-inch casing. So I let my water circulate, via a garden hose, much longer for the purpose of getting chlorine presence at the bottom of the hole-- over 24 hours. I hope I succeeded. If you have a 5 inch casing, I suggest that you get the pellets made for the purpose. For the saved "flooding volume" water, I used a garbage can line with a clean "yard waste" bag. I used a piece of 1/2 inch vinyl tubing to do the transfer into the well, to make a siphon line. I sanitized the tubing before using.

Regarding flushing, my Centaur Carbon filter uses raw well water for the backflush, which is done every 3 days.

Regarding settings, I don't know how the test would be at the limit of its detection range. It was suggested that you increase the dose. As you pointed out, the expense is small for you. Come to think of it, $1 per month seems very low. That would not buy a gallon of chlorine bleach.

Ha ha! Yeah, it was Moravec that I got in touch with! And actually, his position, which no one else seems to emphasize, was corroborated by info I tracked down from health department publications up in Canada.

By setting up the proper solution and dumping in hundreds of gallons there was NO question as to whether I was hitting the bottom of the well :D Of course, this was only for use in initial rehab and would not be something possible (along this scale) with a production system (w/o work).

Again, my backwashes are using treated water, but some of that water might not be fully subjected to the proper time period in which to destroy bacteria. When you have to deal with bacteria it adds another layer that complicates things: for me none of what I have on its own is very high in levels, it's just that combined it all presents a complex situation (one that I'm sure finally put the PO over the edge enough so that he resorted to trenching out for a 1/3+ mile feed line, excavating and dropping in a cistern and then plumbing and wiring that to the pump house).

When I first calculated out how much H2O2 I could expect to use over the course of a year I kept thinking that I'd erred in my calcs. It turned out that I really wasn't that far off (mostly because I didn't factor in the water consumption from the backflushing, in addition to all the messing around with testing trying to get things dialed in). The other thing that I found comforting is that the potency of the H2O2 (staring at 7%) didn't really noticeably fall off over the course of a year: I tested residuals just before I restocked and then after I'd restocked and they were pretty much the same; of course, the "new" bottle was also a year old, but it hadn't been opened and mixed- not exactly scientific, but a pretty reasonable indicator, I feel.
 

Bdiggs

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Hey WellOff,
I think I remember reading that peroxide is much more stable than chlorine as far as shelf life goes? Losing only about 1% per year? (Link here) I'm also thinking/trying to remember that some of the 7% peroxides used for water treatment have a few (and the ones used for disinfecting, the non-food grade kind that you buy at the store have a ton) of other chemicals added as stabilizers so they degrade less (but are also why the store ones can't be used in water treatment - too many additional chems). I'm not sure if the higher percentage food grade ones have any stabilizers or not, but it is neat to see your real world experience with the potency over the course of a year with the 7% kind.

I was wondering (and I have my own questions about this as I'm looking at a similar setup); could this come down to a pH thing? You'd think that the H2O2 would get the job done regardless, but, while ferrous iron starts to precipitate naturally/become ferric at 7+, manganous manganese doesn't naturally start to precipitate out until around 8+, or higher? (which is why people with manganese often have some black on the insides of their dishwashers, I think, because I think I read somewhere that those soaps get the pH pretty high in there and do this, and I have seen these iron/brown/orange and manganese/black stains in person). (by the way, I also read, I think in a brochure for Birm, possibly, that at 8.5 you can begin to have problems with the iron becoming colloidal and hard to filter out so maybe to keep it under that if you're trying to get pH up as part of a strategy to get manganous manganese out with ferrous iron present).

Anyway! I know that raising the pH comes from the original ways of doing that and and then using mechanical filtration to catch the iron and manganese precipitation, but it also helps with the Manganese Dioxide based oxidizing medias like you've been recommended perform a little better too, I think, especially with manganese. However, with your peroxide setup, and the peroxide residual there after the contact tank, you'd think it would have already oxidized those things. Especially with the pH not being acidic and given that some people don't even use a contact tank for peroxide treatment if there's not bacteria involved, just letting it all hit the catalytic carbon and precipitating there and removing the peroxide in one step. Really, there's only three things that can be majorly adjusted, right? Oxidation level (which you've increased), pH level, and contact time (which, I'm guessing based on what others have done, but there should be enough of, at least for just oxidation with peroxide, right?). Oh, and I guess the precipitation/sediment removal step, but that (the carbon) seems okay? Unless you could somehow put in a sediment filter after the carbon (or use something similar in the house) and check that out to make sure it's not just missing particulates. <--edit - scratch this because you said you were using a dual grade DGD-2501 sediment filter after the carbon.

Here's something interesting that got me to wondering about the pH, though, from the posted article on disinfection:
"Chorine is 100% biocidal at a pH of 5.5 but is 100% oxidative at a pH over 10. When 50 ppm chlorine is mixed into water with a natural pH of 7.1, pH will rise to 7.6. The biocidal effectiveness is now 34%. As pH rises, chlorine becomes more oxidative in nature."

So, I'm wondering if having the pH a little lower than manganese may naturally precipitate out for, that while your peroxide is still biocidal (given the proper contact time, which I've heard can take even longer/be harder with IRB than with chlorine, possibly.) - but I'm wondering if the peroxide may not be as oxidative as it needs to be for the manganese (without an incredibly, incredibly long contact time, if then)? And if your pH was a little higher, maybe even like 7.5, then it would be fully oxidizing all of it, but near 7 the pH is just a little too low for the manganese to fully precipitate?

Someone with much, much more experience will have to weigh in on that though, because I still have lots of questions about pH when it comes to chlorine and peroxide treatments that I'd like to ask too. But, reading through this thread the information has been helpful to start learning on that. So, thanks! And, it was just something I thought worth mentioning - maybe someone with more experience can confirm or deny that pH has anything at all to do with it in this case when it is already around 7.
 
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WellOff

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bdiggs, great contribution there! It's the angle that I strive for, to actually understand what's going on.

I got to digging around, now that you got me to thinking about pH, and here is the best "answer" that I was able to dig up:

www.deas.harvard.edu/environmental-chemistry/publications/IronManganeseScotMartin.pdf

There is WAY more than I care to try and decipher (I skipped chemistry classes :(), but I am able to parse out that Mn tends to require higher pH levels to oxidize. Dissolved oxygen levels, however, appear to, if I'm understanding what they're saying, overcome the pH issue; Figure 1 (graph; pg 38) shows this correlation. What I see is that DO of around 15% is sufficient for a pH of 7.0. Other reading suggests that most base water is (should be/averages to be) around 7% to 10%. Try as I might, and perhaps I'm getting too cross-eyed now, I can't seem to come up with anything that can more readily tell me how much my H2O2 is boosting DO: seems like that should be simple; I'm injecting about 4ppm pf H2O2 solution (which is made up of 7 parts H2O to 1 part 7% H2O2); the first graph that show Fe is also interesting. The equations are all there, anyone who can parse them can just plug in their numbers and be able to figure out exactly what's needed.

"So, I'm wondering if having the pH a little lower than manganese may naturally precipitate out for, that while your peroxide is still biocidal (given the proper contact time, which I've heard can take even longer/be harder with IRB than with chlorine, possibly.) - but I'm wondering if the peroxide may not be as oxidative as it needs to be for the manganese (without an incredibly, incredibly long contact time, if then)? And if your pH was a little higher, maybe even like 7.5, then it would be fully oxidizing all of it, but near 7 the pH is just a little too low for the manganese to fully precipitate?"

Yes, H2O2 is not as strong a biocidal as chlorine. While one has to deal with the reducing bacteria, in my case it's not that heavy of a load: I have not tested for it post installation of my system; however, I know what to look for and I've never seen it past the contact tank; I see no clogging, and I get no bacteria showing up in lab tests, so I'm inclined to believe that my system is working well (100%?) in this case. And seeing next to no Fe show up in lab tests I'm also sure (99.99%) that the iron is being handled by my system. So, where does this all leave me and my Mn problems?...

Best I can tell is that the Mn is requiring yet longer contact time or that I need to really jack up the H2O2. Longer contact time would require installing another contact tank (may be another way, but I'm not thinking that anything is going to be all that practical- water restricter or such). I'd pumped up the H2O2 levels but maybe not enough? Some of what kept me from really cranking it up was that Stenner doesn't say anything about this, they only give a guide for solution levels (ppm of H2O2): I'm not starting to see that Stenner is likely just regurgitating something and that they themselves really don't have the background to understand this- and the bad thing is that they're pushing this out to a LOT of "laymen." I always want to now HOW MUCH, and, given the above paper/document this is something that is readily determinable (yes, there are various factors, but I think that the equations can generate something a LOT better than "just crank it up" sort of "calculations." Right now I am constrained by the starting solution concentration (as noted above, 7 parts water and 1 part 7% H2O2)- will just "cranking it up" be enough? Yes, I could dump the tank and test with another

I'd like to thank you, bdiggs, for inspiring me to do research on the effects of pH on Mn. It is most definitely key: and the vendor I purchased from is partly correct, but failed to convey why; and, I don't think that he really does understand the relationship.

So, where I am at now is that I may look to really tweak the feed rate up and see what happens: if I could calculate the expected DO I'd feel a lot better (something to measure by). This, however, might not be conclusive as the carbon may just be unable to extract the Mn. I am in discussion with someone here about going the route of changing the carbon out for a media with MnO: this media provides excellent filtration, in which case I can provide carbon at a lower level, perhaps replacing my dual density Pentek carbon cartridge/filter (in the BB).
 

Reach4

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There is WAY more than I care to try and decipher (I skipped chemistry classes :(), but I am able to parse out that Mn tends to require higher pH levels to oxidize. Dissolved oxygen levels, however, appear to, if I'm understanding what they're saying, overcome the pH issue; Figure 1 (graph; pg 38) shows this correlation. What I see is that DO of around 15% is sufficient for a pH of 7.0. Other reading suggests that most base water is (should be/averages to be) around 7% to 10%. Try as I might, and perhaps I'm getting too cross-eyed now, I can't seem to come up with anything that can more readily tell me how much my H2O2 is boosting DO: seems like that should be simple; I'm injecting about 4ppm pf H2O2 solution (which is made up of 7 parts H2O to 1 part 7% H2O2); the first graph that show Fe is also interesting. The equations are all there, anyone who can parse them can just plug in their numbers and be able to figure out exactly what's needed.

I get cross-eyed too, reading it, but it is interesting. It seems to me that 7 parts H2O to 1 part 7% H2O2 would give 7/8% or 0.875% or 87500 ppm. Maybe that is what is in the solution tank. Then the Stenner pump would be set to add more water at the ratio of 21875 to 1 (or is it 21874 to 1) to give the 4 ppm.

While you are researching, other than cost, have you seen a reason why you can't convert a chlorine bleach water treatment dose, where you are trying to oxidize minerals, to a hydrogen peroxide dose-- if you can get the right equivalence ratio? Could it be that simple? So why? If its faster, that sounds good. So the hope would be that for a given piece of hardware, it might be effective than bleach with the same contact time.
 

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Yes, the Stenner pump's injection is metered and delivered in pulses (triggered for each gallon of water flow reported by the meter [which is separate from the Stenner pump]). The pumps usually come stated as having a certain output range, this is based on some jumper setting on the device's electronics board: there's like three different range groups (refer to manual)- I'd toggled between a couple of them, initially having to have the rate set very low (because I was only looking to inject about 1.5ppm, if I remember correctly). Within each range grouping you have the ability to adjust through that range: the metering dial. I have a controller that is connected up to a meter that generates pulses for water flow; each pulse is picked up by a Stenner controller which then runs the pump.

While H2O2 is a much better oxidizer than regular chlorine (sodium hypochlorite- NaCIO) it's not necessarily an automatic slam-dunk replacement. From my layman's knowledge there are a few issues to be concerned with:

1) Bacteria loading- NaCIO is a much better biocidal;
2) Long delivery/distribution piping- there's a reason why municipal water suppliers mostly use chlorine and that's to leave a slight residual for keeping the delivery/distribution lines from becoming laden with bacteria; (I have had to regularly shock my plumbing due to bacteria starting to colonize- not sure if my problem has been related to insufficient shocking, though I would like to believe that I've got enough experience that I should know how to do it right- I recently have switched to using H2O2 to shock with [adding food coloring so I can spot when it hits each faucet etc.]);
3) H2O2 may not play well with downstream treatment and filtration equipment- you have to be careful to match things (I was told that I could swap out the media and run NaCIO, meaning that I couldn't continue to use the Centaur carbon media that I was using with H2O2 with NaCIO- figure that this would also likely be the case if looking to go the other way (from NaCIO to H2O2) for other cases.

In my case Fe an Mn are my primary issues. IRB, of course, HAS to be dealt with as well, in which case I have to have a biocical function up-stream.

As a continuing follow up to my problem I am now starting to see that I am not getting sufficient breakdown and filtration of the Mn, that the Centaur carbon is NOT able to deal with the Mn. Further, the last lab tests showed that the Mn in my treated water (at the faucet) had higher levels of Mn than the raw water! This could only mean that Mn is collecting and sloughing off; I suspect that it's being charged/stored up in the carbon tank due to the backwashing cycles overrunning the contact tank's function (contact time): I have been concerned about this being an issue a long time ago and expressed my concern (though I couldn't paint the picture up until now) to the vendor- the vendor never did attempt to answer/address this concern (either ignorant or trying to not own up to the fact that they knew this could be an issue and just hoped that I wouldn't notice?). My non-scientific measurements on water quality seems to always indicate that my water quality is poorer following a backwash. Much of my frustration is due to the fact that it takes a good three weeks before I can get any results on Mn testing back from the lab! I'd gotten a Hatch test kit for Mn, but it SUCKS! (not reliable at all)

Again, as someone here has suggested, going with an MnO-based media in my backwash tank (which currently contains my Centaur carbon) is likely the answer for me. The backwash cycle would continue to purge and then be restocked with water which has minimal contact time with H2O2; but, with MnO media in the tank that Mn will be oxidized and captures by that media.

I can really only speak based on my situation. Any "knowledge" that I put forth here is that of a layman and is not to be taken as professional advice (always do your research). And as always, and for everything, I am perfectly happy to be corrected on any point.

Reach4, if you wish you can PM me (so we don't clutter this thread). I've had a lot of free help so I feel a bit obligated to reciprocate: I have a passion for this (if I could go back in time I'd have looked to get in to this field).
 

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It's been over a year since I posted and I kind of wanted to provide a bit of an update.

I'm sitting pretty much where I was when I last posted. I changed out the [old?] Centaur carbon with some coconut-based catalytic carbon: I don't think that the coconut carbon makes the water quite as clear as the Centaur. I also installed an automatic flush valve on my contact tank: I'd only been periodically flushing it. Also changed my backwash frequency to every-other day and cut back the cycle times: prior to these changes the backwash was running through about 110 gallons which, clearly, was overrunning the contact time in the 40 gallon contact tank.

I tried a quick test of Katalox Light, using a drop-in cartridge (setting the backwash filter on bypass), and, sadly, I wasn't able to see any measurable differences, not enough to prompt me to do a wholesale swap out in my backwash filter.

I'm now using an eXact micro tester/kit (bought H2O2 test separately). After initial difficulties I feel that I am able to use it confidently: sure beats waiting weeks to get back tests on iron and manganese!

I'm going to do some more tests to update the numbers. My raw water numbers have been very stable over the years. My treated numbers were pretty good up until I started reading iron: the manganese has really never been dealt with; it was the sudden appearance of iron (again, this is post treatment/filtration) which has really bothered me.

I haven't changed the hose on the Stenner (after about 34 month of operation). If not for the fact that I'm seeing an ample amount of H2O2 post contact tank (1ppm now) I'd suspect that hose.

And a thought just hit me... Is the backwash filter in bypass still? Hm... I could swear that I went by-the-book when I changed out the media (and after doing the test with the Katalox Light). Well, stay tuned- I'll report back on whether I shot myself in the foot or whether this continues to be an exceedingly puzzling issue.
 

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Backwash filter set to "Service" (was hoping that it wasn't- not so fortunate!).

Nothing more frustrating than inconsistent test results! the eXact micro isn't counting up to 40 (seconds) like it says it should after the 20 seconds of mixing the reducer (I just don't use this thing often enough to have it come easy to me; but, given 6 different readings I think I got re-tuned to it by the time I finally threw my arms up [again]!). I only had enough patience for testing iron today. The test is for up to 6ppm of iron (according to eXact).

Direct samples in my pump house post-treatment/filtering tested:
1. Hi
2. Lo
3. Lo
4. Hi

I can't really say whether I zeroed things out correctly on the middle two. For sure the 4th one, and, I'm figuring, the first one too. So, let's just call it Hi, which is above 6ppm.

Sample from my master bath sink faucet:

1. Hi

If that had read Lo I'd have stopped right there and went out drinking!

Samples from RAW water (taken outside my pump house- faucet that branches directly off the main line from the pressure tank):

1. Lo

I've had numerous lab tests and for iron it's always been around 2ppm for raw; ALL post-treatment/filtering has been either near zero or not detectable.

Only thing that I could think of is that the eXact micro tests for iron can't deal with IRB. If that's the case then that would explain why iron shows up lower in the raw. The issue with iron being higher in the treated/filtered water is still baffling, which would mean that the carbon tank is totally failing (how that is happening isn't clear- it HAS worked, as evidenced by actual lab test in the past).
 
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