Well sanitizing (extra attention to 4 inch casing)

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Reach4

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My favorite well sanitizing procedure that I have seen is
http://www.moravecwaterwells.com/disinfection

However I have some added thoughts that point to needing larger flooding volume (F.V), more bleach than predicted, and more vinegar than predicted maybe.

During the process, you recirculate water from a hose spigot to the top of the casing, you add bleach and vinegar, in turn, to the top of the well casing. This recirculation is mostly limited to area A (above pump) shown on the sketch. Area B (below pump) does not have significant flow. If you had a 5 inch casing, you could drop pellets made for the purpose to the bottom of the well. I don't think that you are usually also dropping acid pellets too, so even those with a big casing might need more flooding volume. The acid is important if your well water pH is higher.

During the procedure, you save a flooding volume of water that can drive chlorine +acid through the casing screen. I think this flooding volume needs to be big enough to drive treated water down to fill area B and to drive the mix through the bottom screen into the nearby aquifer. If the pump is set up from the bottom a fair amount, that flooding volume needs to be larger than the numbers from the Moravec procedure.

img_well_san2.png

Some people can run a hose from a neighbor's well to provide the flooding volume (mix extra bleach and vinegar as you go). Some will have a big rain barrel or some other clean container. A new hard side "free flow" waterbed mattress can hold a lot of water. These are often sold with a venturi pump that is intended to empty the mattress. While you can do a good job with a siphon, that pump will draw a vacuum that can even overcome a little air leaking into the connection. Note that these plastic waterbed pumps have two positions: fill and empty. The water comes out of the little pump with no fitting, so that pump must be positioned over a funnel that feeds the water down the casing.

Regarding calculations for how much bleach to use, bleach gets consumed by reacting with materials in the well. I think it is important to use some high-range (200 ppm) chlorine test paper such as Hydrion Cm-240. You won't find high range chlorine paper at a pool store, but you may at a restaurant supply house. Chlorine test strips are very useful to see how clearing out the chlorine at the end is going. Note that the chlorine to your softener should be limited. You also want to minimize how much chlorine you put into your septic. Septic tanks are somewhat resilient but I don't have any way to quantify that. I used a utility pump to send some inside water to the ditch.

Vinegar is a good acid to use. It is not dangerous like some others. My warehouse store sells two 1-gallon jugs of white vinegar for under $4. In your well analysis, you get a pH number and you get an alkalinity number. Huh? Aren't those the same? Nope. The calcium carbonate and magnesium carbonate make the pH higher, but only to a point. They form a weak base but they can cancel out a lot of acid. The math and chemistry to take that into account is way beyond me, so I recommend using an inexpensive pH meter or pH paper that covers down to pH 5 or at least 5.5. I would like to have my sanitizing well water lower than 5.5 but 5.5 should be enough. See notes below.

Do not mix the bleach and vinegar outside of the well. Let the water circulate one before adding the other. Take your chlorine and pH readings on the recirculating water, allowing time for the water to recirculate. You will probably need more bleach and vinegar than the Moravec procedure calculations because some will be used up in doing their jobs.

I am sure that I take a lot longer to do this stuff than I need to. To pay somebody to do this would be very expensive, since a lot of the time is just waiting.

Back to that picture again... when clearing out the chlorine from the well fairly quickly, you can't just run a hose from the hose spigot to the ditch. That water will come from the aquifer, through section B, and into the pump. Area A will stay stagnant when viewed in a time frame of hours. So I think to clear the chlorine, you have to continue to recirculate water through the top of the casing while you are dumping water to the ditch. This may require a hose splitter and more hose.

Few people put much thought into sanitizing. Most people never do it, or just pour a jug of bleach into the casing when symptoms develop.

Notes:
  1. Inexpensive pH meter should be calibrated before each use. The 4.01 Buffer Solution Powder packets, that you mix with 250 ml (250 grams) of distilled water, can be very inexpensive. The Pocket Digital PH Meter Water Tester Pen with an LCD display, can be very cheap. To store, fill the cap with 4.01 or 7 ph buffer solution, insert the meter into the cap, and store cap-down. That meter and buffer are often cheaper than good pH strips, and the meter is easier to interpret.
  2. If you use paper pH strips, the Hydrion pH paper range 4.5 - 7.5 (334) seems ideal for this where the target is about 5 pH. I used the more common Hydrion (067), which is adequate. Avoid the cheapest books of pH paper from China. They don't work nearly as well.
  3. I use Hydrion CM-240 200 ppm test roll to measure my chlorine level for disinfecting. Chlorine levels drop as the chlorine does its job, so replenish the bleach as needed.
  4. This write-up is oriented to bottom-feeding deep wells with submersible pumps.
 
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Jeff_Bathroom

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Wow, interesting info. I'll keep this url in my info file. Thanks.
Know anything about batch solar water heater maintenance, or whether it is required periodically?
 

Richard Cropper

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Thank you Reach for that! I used the moravec procedure and that is what gave me about a years worth of no symptoms. Like you said it is alot of work I will just have to make time for it. That's why I was toying around with another way as well. Thank you!
 

Andre Martinez

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Very good info and helps with putting this plan together. Would you say it would be beneficial to recirculate the water in lines every hour or so while in the sit and wait stage to keep the water in A from not being staganat as long and flush to get deeper clean in well.

I was unsure about those strips on Amazon they don't specify if it's total or free chlorine. And I would residual strips as well correct?
 

Reach4

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I was unsure about those strips on Amazon they don't specify if it's total or free chlorine. And I would residual strips as well correct?
Residual strips are to sensitive. You want high range indicator paper that go up to 200 ppm. A restaurant supply place would have those, but if you just look for high range, that is the thing for disinfecting. You would want to measure free chlorine, but you need high range.

I use Hydrion CM-240
 
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Andre Martinez

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Residual strips are to sensitive. You want high range indicator paper that go up to 200 ppm. A restaurant supply place would have those, but if you just look for high range, that is the thing for disinfecting. You would want to measure free chlorine, but you need high range.

I use Hydrion CM-240

Correct but I am asking in reference to when I am finished to test that chlorine is below the recommended percentage.
 

Reach4

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Correct but I am asking in reference to when I am finished to test that chlorine is below the recommended percentage.
Ahh, yes. The nose knows, but you would want free chlorine for that. City drinking water can be 4 ppm, so that would be a target. Pool chlorine tests are in that range.
 
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Forgetting the instruction here to buy Hydrion brand pH test strips, I ended up with made-in-China LabRat Supplies brand. Total mistake. Once bleach was added, the LRS-4801 test strips stopped working completely. They just bleached out pale. From then on my pH level was unknown.

I carried on regardless, however, and in the end, results have been great. I'll be doing this now once a year, possibly twice. I didn't have too very much H2S smell before, but now it is completely gone. Iron staining too is much reduced. No iron staining in the toilet bowl at all. Some iron staining still on the shower curtain, but that is from standing beads of water with dissolved iron being left to dry out exposed to O2.

When turning on the taps once again, disgusting gray water poured out for a while. But in time that stopped, and it became clear. A month has passed since I did it, and still my water is very good. This with no other water treatment installed yet at all.
 

Dave Bowers

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When I last shocked my well it turned up a ton of black, rust, dirty water, etc. I have no idea when, if ever, the well was shocked last.

My question is, if I have to shock my well every 3-6 months, will that nastiness ever go away?
Will the nastiness reduce each time, so it's more manageable?
If not, what is the best way to not have it enter your whole house system?

Also, should I run the chlorinated water through my softener, dishwasher, fridge, etc, or just the main faucets and showers?

Thanks,
Dave
 

Reach4

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Dave:
Do put in a whole house cartridge filter. I think even city water should have that. Mine is before the softener, but after has some good points to. I use Pentek 4.5x20 DGD-5005-20 cartridges, and am going a couple of years on each cartridge. However that is after my iron+H2S backwashing filter which takes out most sediment in addition to its main jobs.

I have limited experience; I have one well. I have sanitized it twice, and it has been 4 or 5 years since the last time. I did not have your experience with the degree of nastiness. You would certainly want to keep rinsing after sanitizing until all nastiness went away.

My writeup does talk about the softener. When sanitize, that involves recirculation. I put a cartridge filter in line with the recirculating water. Do run chlorinated+vinegar water through everything, but strongly limit the strength that the softener resin sees. My cartridge collected some rust-colored stuff, but not what you saw.
 

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@Reach4
I am putting a whole house filter in prior to shocking the well. The parts are on their way!! There was no way I was letting that nastiness back into the house. I am installing (2) 4.5 x 10 inch blue housings. One will act as a pre-filter at 20 microns (might go up to 50), and the second will work at 5 microns. This is my initial thought while sanitizing. I will probably adjust that if I can ever get rid of the nasties.

Any thought on where that nastiness comes from? My first guess is from the side walls of the well casing. I figured the chlorinated water from the casing wash down was knocking off all the rust, scaling, etc. Again, with me not knowing the history of the well, I don't know. However, based on the rest of the house's maintenance, I'm guessing it was never done! That is why I am hoping after 1 or 2 times of sanitizing that nastiness might go away???

Thanks again!
 

Reach4

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I sanitized spring of 2016 and did it again spring of 2020 -- 6 years. Too long.

I am sure the need varies from well to year, but I think 3 or 4 years will be good for me with my overkill sanitizing. The SRB and IRB are said to be slow growing.

I do run a filter on the recirculating water. I bought a 4.5x20 washable pleated polyester filter cartridge. I have a Pentek Big Blue housing with garden hose fittings added.. After the sanitizing operation, I opened the filter, and dumped orange sludge on some bushes. Rinsed with water. I would estimate 1/2 cup of sludge. The filter had been washed clean of chlorine during the chlorine removal operation, so no harm to the bushes. While getting rid of the chlorine, you want about half of the pumped water to recirculate, and about half of the pumped water to be discarded. The recirculating water cleans out the space above the pump, and the water from below in my bottom feeding well is quickly free of chlorine.
 
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My well is 5" in diameter, 120' deep and the pump is set at 44' from the top.moravec calls for a 10% Flood Volume, how much Flood Volume do you recommend?
 

Reach4

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My well is 5" in diameter, 120' deep and the pump is set at 44' from the top.moravec calls for a 10% Flood Volume, how much Flood Volume do you recommend?
I compute your well volume to be 77.52 gallons below the pump. I would probably use about 150% of that amount. I could see as little as 120%, but I like to be sure. Yes, that is a lot of volume. Maybe use 4 33-gallon trash cans lined with plastic liners. Your flooding volume should be dosed.


I recommend you don't put much faith in the calculations for the amount of bleach and vinegar that will be consumed. You could use that for an initial dose, but I am confident you will need significantly more if you go by chlorine and pH measurements. Measure, and add more to bring up the concentration. Recirculate some more. Measure again. Dose again.

I did not find the string "10%" in the Moravec article.
 

Zenon2cubed

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In the article they provide a table, I backed out their calculation: 50 G standing -> 5 G Flood, 100 G standing -> 10 G flood...
Flood with 150% of well volume below the pump? The closest neighboring well is about 250' away, do I risk pushing chlorine into their well?
 

Reach4

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My model is that I need to displace that untreated column of water. Now if I had dropped chlorine pellets and acid pellets past the pump to the bottom of the well, then a smaller flooding volume could make sense. But I would still wonder if there was a big sandwich of untreated water between bottom and pump.

I am not a pro. 250 ft seems like a lot to me, but I cannot be sure. Hey, maybe you and the neighbor could sanitize at the same time.
 

Zenon2cubed

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It's been about 3 weeks since I sanitized the well and the water is still nice and odour free, previously there was a faint smell that would come and go.
The process was uneventful: no angry neighbours, no sludge in my water filters, no downside at all

I set aside about 90 litres of flood water due to availability of clean buckets.

I calibrated my chemistry in a sample bucket the day before and then scaled up when I sanitized the well.

One odd thing I noticed was pH change, I dosed my flood buckets before starting the process and a few hrs later when it came time to dump the flood water I did a quick test with my pH strips and found the water to be much less acidic.
Could this be the acetic acid reacting with hardness in the water? If so, this process takes a bit of time...
 

Reach4

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pH rises also due to the activating the chlorine I think. Chlorine bleach has a high pH.
 
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