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  #1   IP: 216.243.100.93
Old October 29th, 2006, 08:13 AM
bluefish67 bluefish67 is offline
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Default Coliform Removal

Hi everyone,

I'm having problems with my well and would appreciate any help you can offer. Here's the short version of the story.

A year and half ago we found out the well had coliform bacteria (no fecal coliform). It was shock treated and tested OK. Last month it tested positive again. I shock treated it twice, but it still tests positive. From the smell and visual inspection, we also have a problem with iron and/or sulphur bacteria.

There are three septic tanks on the property. The inspections said they were sited far enough from the well.

My questions:

- Where is the coliform coming from? Why is it returning?

- Could a septic be the cause? Some people have said that since there is no fecal coliform, the problem is not coming from a septic. One person said this might not be true.

- Why did the shock treatment not work?

- Do we need a new well?

- Would the new well become contaminated?

- Is the iron/sulphur bacteria interfering with the shock treatment?

- Given the problems we've had, does it make more sense to just treat the water after it comes out of the well?

- Are there other options than a new well or water treatment? Did I do the shock treatment wrong?

Below are more details for those with the patience. Sorry for the length, but I want to give enough info to people who might be able to help.

Thanks,

-Scott

---
The details:

The well is 150 feet deep, 4 inch casing. The well feeds three houses on the property. I don't know the age, but the well company says it will probably need to be replaced soon. Even though it's old, getting several more years of life out of it would help, given our current financial situation.

We bought the property a year and a half ago. During the sale, the well was tested and came back positive for coliform. I assume that the previous owners did not know of the contamination, or else they would have treated it before they put it on the market. Why risk undermining a sale, when they knew they would have to treat it anyway. So, I'm assuming the contamination has been there for some time. They owned the house for the previous 15 years.

The well company treated the well. I didn't pay too close attention, but I believe they used some kind of dry, granular chlorine, not pellets. I ran the water through all the fixtures, as directed by the well company. I had a hard time telling by smell whether enough chlorine was coming out, especially after doing three houses. But after finishing, the water tested fine.

Last month, we did a follow-up test. It tested positive for total coliform. I did the shock treatment myself, using several quarts of 6% household bleach, in a single application. This was calculated to give a concentration of about 50 ppm. I flushed the water down the casing, ran it through the fixtures, and let it sit. Again I had difficulty knowing there was enough chlorine. The water still tested positive for coliform.

I repeated the shock treatment. This time I used high range chlorine test strips. I added chlorine then cycled it through the system using a hose for about 20 minutes. The strips showed 300+ ppm. I ran it through the fixtures, checking the chlorine level each time. When the level dropped below 300 ppm, I added more chlorine and cycled. When I finished, I added more and cycled it, so that there was a high level left in the well. It sat for about 15 hours. All told, I used about 2 gallons of 6% bleach in four applications.

After all this, it still tests positive.
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  #2   IP: 68.32.141.35
Old October 29th, 2006, 08:21 AM
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mdshunk mdshunk is offline
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There is no upper limit for chlorine. Where did the 300ppm number come from?
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  #3   IP: 216.243.100.93
Old October 29th, 2006, 08:33 AM
bluefish67 bluefish67 is offline
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The chlorine test strips I bought maxed out at 300+ ppm.

I wasn't sure what level I should shoot for. For treating coliform, most sites recommend 50-100 ppm.

We also have iron and/or sulphur bacteria. I've read recommendations of 200 ppm, even as high as 1000 ppm for that. I wanted to improve the situation with the iron and sulphur bacteria, but I've read that the problem is frequently very hard to fix. Shock chlorination frequently helps only temporarily.

I've read that iron bacteria (or possibly its byproducts) can consume/neutralize some of the chlorine. But then I've heard that too high a chlorine level can reduce the effectiveness of the shock treatment. Damn, this is confusing. But for most people, it seems like the shock treatment just works.

Thanks for any help you can offer.

-Scott
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  #4   IP: 68.32.141.35
Old October 29th, 2006, 09:04 AM
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It seems like you're going to have to set up a chlorine injection system. That's what I had to do. There is a user, Gary Slusser, who's the expert on such matters. I'm going to see if I can get him to read this thread.
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  #5   IP: 71.219.228.148
Old October 29th, 2006, 09:18 AM
K2eoj K2eoj is offline
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Chlorine will treat the pipes etc. from the well . Normally we do a chlorine treatment on a new well because the pipes are dirty for a number of reasons. I would say your well is contaminated. Not knowing your particular area and soil conditions I would be going to the local health dept. and asking questions. Chances are they have knowledge of this situation. In my state there is also "Division of water resources". My area rearly if ever encounters a contaminated well but 20 miles from here in the mountains a fisure in the rock can cause septic tho go directly into the water supply.

They do make chlorinators which are required on commercial wells in my area. That would treat all the water comming from the well but you probably would not use it for drinking.
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  #6   IP: 67.70.107.127
Old October 29th, 2006, 09:35 AM
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Bumblerazz Bumblerazz is offline
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Wow! lots-o-questions and no easy answer. Chlorine at the levels and time line you are describing should be sufficient. The bacteria can be coming from several sources.


Quote:
Originally Posted by bluefish67 View Post
A year and half ago we found out the well had coliform bacteria (no fecal coliform).
Fecal coliform is just what they call an indicator species, meaning that if you have fecal it usually means you have other types as well. Not having it doesn't neccessarily mean you don't have bacteria, unusual but possible.

Quote:
Originally Posted by bluefish67 View Post
From the smell and visual inspection, we also have a problem with iron and/or sulphur bacteria.
Iron and sulphur are usually not associated with bacteria, more from dissolved metals/compounds in the earth. If this is new to the well then I would say that wherever it is coming from, it's likely the source of the bacteria as well.

Quote:
Originally Posted by bluefish67 View Post
There are three septic tanks on the property. The inspections said they were sited far enough from the well.

My questions:

- Where is the coliform coming from? Why is it returning?

- Could a septic be the cause? Some people have said that since there is no fecal coliform, the problem is not coming from a septic. One person said this might not be true.
Over time ground water makes "paths" causing it to flow down areas of least resistance. Continuous draws from a well can cause water to create a path of least resistance to that well. Despite the septic being "over the minimum distance", over time they can infiltrate the well. Again, unusual but possible.

Quote:
Originally Posted by bluefish67 View Post
- Why did the shock treatment not work?
It may have. The biggest source of false positives can be how the test sample is taken. Wash the tap thoroughly and DO NOT TOUCH THE MOUTH OF THE SAMPLE BOTTLE TO ANYTHING, not your hand, not the tap, not anything!! Tap ends are a nasty area and are not affected by chorine in the water. Also use a very clean sample bottle. The best is those supplied from the lab, but if not that then a freshly opened bottle of bottled water (as in open it the minute before taking the sample).

The easiest way to make sure it's not the tap or any pipes in the line is to take the sample directly from the well, of course ensuring that the mouth and inside of the sample container is not contaminated.

Of course, use a government certified lab. You can even try the municipality lab. They sometimes accept samples from external clients.

Quote:
Originally Posted by bluefish67 View Post
- Do we need a new well?

- Would the new well become contaminated?

- Is the iron/sulphur bacteria interfering with the shock treatment?
Unknown until the source is identified. Fe/S usually would not effect Cl- treatment, especially if the free Cl- in the water is over 200ppm and steady.

Quote:
Originally Posted by bluefish67 View Post
- Given the problems we've had, does it make more sense to just treat the water after it comes out of the well?
Possible but expensive, requires constant monitoring and an overall pain in the a**.

Quote:
Originally Posted by bluefish67 View Post
- Are there other options than a new well or water treatment? Did I do the shock treatment wrong?
You may have missed something in the treatment stage. Did you wash down the sides of the well when chlorinating? If the well casing is starting to corrode (the only reason I can think of for the well company saying it has to be replaced. I mean if it's supplying sufficient amounts of water, why change?) Pits and cracks in the sides can house bacteria despite a heavy concentration of Cl- in the water. Dissolve some of the chlorine in a large bucket of water and spray and wash the sides of the well as best you can with a highly concentrated solution (or course being carefull not to spray yourself or anyone helping. Be carefull of the vapours as well). Of course the sampling is critical, as described above.

Another source may be from surface contamination. As wells get older the collar of earth around the top of the well can loosen and run-off surface water can run down the outside of the well until it enters the water of the well. This surface water of course contains all the crap that is found on the surface. Of course rain is now quite acidic so it easily dissolves material it comes in contact with, so if you have animals mulling about close to the well (cows, deer, flocks of birds,...) that water can dissolve and carry their waste into the well.

As I mentioned above, if the Fe/S are a new problem as well, then I would look to that as a possible source. So if there is a new housing development in the area, industry that has started to dump or has had a spill, if the well casing starting to corrode or you've started using a new fertiliser or pesticide, these might contribute to a well having a problem, even if it's 150' deep. Just think of Walkerton in Ontario, Can. as an example.

Quote:
Originally Posted by bluefish67 View Post
I ran the water through all the fixtures, as directed by the well company. I had a hard time telling by smell whether enough chlorine was coming out, especially after doing three houses. But after finishing, the water tested fine.
If you can smell the Cl-, then your ok as far as concentration.

Quote:
Originally Posted by bluefish67 View Post
using several quarts of 6% household bleach, in a single application. This was calculated to give a concentration of about 50 ppm. I flushed the water down the casing, ran it through the fixtures, and let it sit. Again I had difficulty knowing there was enough chlorine. The water still tested positive for coliform.
Interesting. How did you do the calculation? Bleach, though it seems concentrated at 6% is nowhere near as strong as the solid flakes or pellets. And further diluted when it mixes with the well water can weaken it to a mild irritant. Of course flakes or pellets will drop to the bottom of the well whereas the liquid bleach will "float" on the surface until mixed, whether by hand or by time (your cycling with a hose should've done the trick though). The flakes or pellets all at once will "shock" it, much like what happens when treating a pool, and pretty much kill all bacteria.

I don't know if I said anything new to you, but hopefully it will trigger a memory of something said or done that will uncover the source.

Good luck,
Jon.
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  #7   IP: 66.174.93.102
Old October 29th, 2006, 05:39 PM
Gary Slusser Gary Slusser is offline
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I've replied to this on two other forums. I disagree that shockng usually works; and that is based on 20 years of shocking wells and testing for Coliform bacteria. Yes too much chlorine isnot good, chlorine raises the pH of the water and chlorine as a disinfectant works best up to a pH of 7.2 or so. There and above it is better at oxidaton, which is this case doesn't count. Here's my reply on the other forums.

Shocking a well is at best a temporary solution which treats the symptom rather than the cause of the contamination. As proved by your experience.

Shocking a well can cause expensive water quality, pump and/or power cable and drop pipe problems.

Bacteria contamination can come from any direction any distance and it can come and go in days.

Of course the best and all but impossible choice would be to find and prevent the source of the contamination but.... that usually is expensive and impossible. While it may take years to clear the groundwater of the contaminated water... So, the next best is to drill a new well BUT, that does not guarantee non-contaminated water. So, treating the water usually is the best doable choice with minimal expense and it comes with a guarantee of bacteria free water as long as you maintain the equipment; which is easy and takes little time.

There are a number of ways to treat bacteria but you have to meet pretreatment needs for some, like UV lights. You have iron abd possibly SRB/IRB so UV is out. I don't like chlorine but, it is usually the best when other parameters limit the use of UV, like your situation plus... you have other people using the water, which makes you a water company if you like the idea or not... and the guvmint guys love chlorine.

So, I would propose my relatively inexpensive inline pellet chlorinator and special mixing tank followed by a correctly sized for the SFR (service flow rate) the houses would require Centaur carbon filter.
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Last edited by Gary Slusser : August 15th, 2011 at 09:47 PM.
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  #8   IP: 67.70.107.127
Old October 30th, 2006, 01:25 PM
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Bumblerazz Bumblerazz is offline
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As depressing as it may sound, Gary is probably right.

To top it off, as Gary mentioned, having two or more homes on the same water distribution network makes you a service provider. Gov regs per province or state vary but all are pretty much the same when it comes to water. I would think that just to avoid prosecution, excersizing a little due diligence by putting in some sort of treatment facility is in your best interest.
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  #9   IP: 68.45.251.29
Old October 30th, 2006, 04:35 PM
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Looks like you're gonna be putting in some chlorine treatment in the line. It's not really as expensive as it seems. Just a little routine maintenance involved is the main pain in the butt. You'll probably also have to keep log records if you're supplying more than one dwelling.
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  #10   IP: 71.219.228.148
Old October 31st, 2006, 12:11 AM
K2eoj K2eoj is offline
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I know of some wells in NJ with chemical contamination. Those people wish their problem was coliform.
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