Very High iron help

[Orion141]

Hi all,

I have been struggling with very high iron levels. We have ~40ppm ferrous iron in our water. PH 6.4, manganese 1.0 ppm. Currently we have the following system:

raw water --> proportional injection of chlorine and pot carb ---> 120 gallon contact tank with blowoff valve --> iron filters (2x 10x54 manganese greensand filters in parallel that each backwash every other day) --> 10x54 backwashing carbon tank --> 10x 54 softener.

When the well was drilled we got about 13 gpm.

We had been running ok after the system was installed with minor issues, but now seem to get dirty water throug the system. As of now it seems like after a backwash of the iron filter (10 minutes at 7.5gpm) we get ~20 gallons of very dirty water that gets through the iron filter followed by clearing of the water. After about 5-6 months of operation we now get dirty water (ferric iron) through the whole system.

One issue I am wondering about is that early on in the backwash/rinse cycle we get relatively clean water (as iron has had a chance to settle in the retention tank), but by the time we get later into the backwash/rinse cycle we start pulling dirty water into the filters. I am wondering if we might need another larger contact tank to avoid this issue.

Anyways this is a troublesome issue and I am wondering if anyone might provide any thoughts here.

Thanks!

 

[Reach4]

One issue I am wondering about is that early on in the backwash/rinse cycle we get relatively clean water (as iron has had a chance to settle in the retention tank), but by the time we get later into the backwash/rinse cycle we start pulling dirty water into the filters. I am wondering if we might need another larger contact tank to avoid this issue.

How about using a contact/settling tank that has a blowoff port. Periodically drain the sediment out. If periodically is too frequently, maybe have a timer control the blowoff through a solenoid valve.

29ppm Clear Iron Well Water - Please help

Hi folks, Long time listener, first time caller here. TL;DR How do we correct for a well producing 29 ppm dissolved Iron, 5.6 pH, 0.684 ppm Mn, 150 NTU Turbidity With many thanks for your suggestions, here's the long version: Background: Well drilled 1995 on Eastern Shore of MD w/ usage of...

terrylove.com

 

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[Orion141]

How about using a contact/settling tank that has a blowoff port. Periodically drain the sediment out. If periodically is too frequently, maybe have a timer control the blowoff through a solenoid valve.

29ppm Clear Iron Well Water - Please help

Hi folks, Long time listener, first time caller here. TL;DR How do we correct for a well producing 29 ppm dissolved Iron, 5.6 pH, 0.684 ppm Mn, 150 NTU Turbidity With many thanks for your suggestions, here's the long version: Background: Well drilled 1995 on Eastern Shore of MD w/ usage of...

terrylove.com

Hi reach,

Sorry, in my post above I omitted the fact that we already have a 120 gallon retention tank with a timed blow off valve. I edited the post to include this info.

One thing I am wondering based upon some water sampling I am doing before and after backwash is whether I need a larger retention tank as early in the backwash the water coming out of the retention tank is relatively clear, but toward the end of the backwash cycle water is pretty dirty coming out of the retention tank. I am wondering if this water overwhelms this iron filter?

 

[Reach4]

So your theory was that there was accumulated sediment from the retention tank getting pumped into the filters.

I am wondering if upping the backwash on the filters from 10 minutes would help. That would be suspecting that the backwash was incomplete. I am not a pro.

I presume the two filters regenerate on alternate days. You will want to make sure they did not accidentally start regenerating on the same day.

Also, when you said "pot carb", what did you mean?

Also, what is the residual chlorine level out of the retention tank?

 

[Orion141]

So your theory was that there was accumulated sediment from the retention tank getting pumped into the filters.

I am wondering if upping the backwash on the filters from 10 minutes would help. That would be suspecting that the backwash was incomplete. I am not a pro.

I presume the two filters regenerate on alternate days. You will want to make sure they did not accidentally start regenerating on the same day.

Also, when you said "pot carb", what did you mean?

Also, what is the residual chlorine level out of the retention tank?

Correct, the two iron filters regenerate on opposite days.

I should have said potassium carbonate (used raise pH).

Residual chlorine out of the retention tank is around 1-3ppm depending upon when I sample.

From what I gather, the backwash appears to be complete as increasing backwash times doesnt seem to help, but rather seems to stir up more iron sediment from the bottom of the retention tank. I say this because early in the backwash water coming out of the retention tank is clear, but later in the backwash/rinse cycle it is quite full of ferric iron. But I am not a pro either.

Thanks!

 

[Reach4]

From what I gather, the backwash appears to be complete as increasing backwash times doesnt seem to help, but rather seems to stir up more iron sediment from the bottom of the retention tank.

Sounds like the retention tank does not blowoff all of the sediment. I looked for a retention tank with a blowoff port on a cone bottom. I did not find one.

When does the sediment blowoff happen?

 

[Orion141]

Sounds like the retention tank does not blowoff all of the sediment. I looked for a retention tank with a blowoff port on a cone bottom. I did not find one.

When does the sediment blowoff happen?

They tanks blowoff in the morning I believe.

 

[Reach4]

I

We had been running ok after the system was installed with minor issues, but now seem to get dirty water throug the system. As of now it seems like after a backwash of the iron filter (10 minutes at 7.5gpm) we get ~20 gallons of very dirty water that gets through the iron filter followed by clearing of the water. After about 5-6 months of operation we now get dirty water (ferric iron) through the whole system.

It worked fine for 5 months. That makes me wonder if some cleaning operation would help. Do your greensand tanks have upper baskets? Maybe those are gunked up, and the backwash rate is now much less. If the backwash was insufficient, the media could not-expand, and the water could just be going through channels. Could you measure the current backwash rate by running the drain line into a 5 gallon bucket, and seeing how long it takes to fill? It should take 40 seconds. You should not have a top basket, but you could have a mushroom shaped deflector.

From what I gather, the backwash appears to be complete as increasing backwash times doesnt seem to help, but rather seems to stir up more iron sediment from the bottom of the retention tank. I say this because early in the backwash water coming out of the retention tank is clear, but later in the backwash/rinse cycle it is quite full of ferric iron.

Suppose the sediment that is getting sucked into the next stage is new sediment that has never made it to the bottom. Then suppose you inhibited the well pump during the backwash, relying on the water already in the contact tank to feed the backwash. After backwash, you let the tank refill.