help on unusual well scale

[rshackleford]

We pulled a pump yesterday and found some unusual scaling in the well. The scale had a jelly-like consistency and is brown to red in color. It is thick. Where the drop pipe is submerged it is half an inch thick and at places it gets up to one and a half inches thick. The well is made in the Fox Hills formation which is bedrock sand. I believe it is part of the Fort Union formation. Below are pictures and typical fox hills water chemistry.

The well is around 1600’ deep. The swl is 200 and pwl is 600’. It has a 40 hp Grundfos pump on 3” galvanized drop pipe. BTW the Grundfos failed.

Conductivity 1900 micro ohms / cm
Sar 52.7
pH 8.53
Residual sodium carbonate 15.26 meq/l
Hardness 1.0 grains/gal 17 mg/l
TDS 1622 mg/l
Sodium chloride 95 mg/l
Calcium 6 mg/l
Magnesium 0
Sodium 500 mg/l
Iron 0
Potassium 2 mg/l
Chloride 58 mg/l
Carbonate 24 mg/l
Bicarbonate 903 mg/l
Sulfate 129 mg/l
Nitrate-n 0

The pictures shows a frozen sample

[Bob NH]

Jelly-like substances are often hydrates which are salts with a lot of "water of hydration" attached to the molecules. There is probably a lot of water in addition to the water of hydration.

It may also be a product of an iron based bacteria that is feeding off the iron in the pipe. The galvanizing is probably gone near the water/air interface.

I suggest taking your sample to the water lab that you usually use. They can probably dilute it and then test it like a water sample to tell you what's in it. They probably have some ideas from their experience.

[rshackleford]

I thought a little about iron bacteria. Tell me if i am right or wrong. Normally the irb would get iron from the water. In this case they are getting it from the well casing and the drop pipe?

[speedbump]

Your test said 0 iron. So if it is IRB, it's not feeding off that. I didn't know bacteria could eat metal pipe though. However it does look like the same slime I'm familiar with.

Could it be some kind of algae?

bob...

[Bob NH]

It could be iron from the pipe as follows:

1. The iron pipe corrodes, producing iron oxide.
2. Now the bacteria can feed off the iron oxide.

[rshackleford]

what i consider to be odd is the amount of this slime. i am not joking when i say it is an inch or more thick on the drop pipe.

this water is know not to corrode or have iron bacteria. the is the best water around. i have trouble believing the pipe is corroding.

it could be algea.

do you know of any testing services that might be able to tell what kind of bacteria it is?

the well casing was provided by the oilfield company we drilled the well for. could there have been somthing in the casing?

[speedbump]

If the pipe is corroding, it must not be galvanized. I have not known anyone to use black iron down a well, but I suppose it is done in some places.

bob...

[rshackleford]

It is common to place black steel in these wells. The water does not corrode.

This particular well does have galvanized drop pipe, steel casing, and stainless steel screen. There is no corrosion on the drop pipe.

[rshackleford]

i looked through water analysis for other wells in this formation. i found the majority of these wells with zero iron, however one did have 1.5 mg/l iron. only one of many though.

[rshackleford]

It must look like I am trying to build a post count here.

I am thinking that this must be an extreme case of irb growth. Our well service crew added five pounds of chlorine pellets to the well after the pump was pulled and before it was reset. The pump had failed and a new one is on order. Unless there are other ideas along the way I will post our finding when the well is pulled to put on the new fluid end. If this was an irb, then we should see a difference in the amount of slime after that shock chlorination. The only thing that really concerns me is that this amount of buildup could occur in less then a year.

[Gary Slusser]

As best I can tell from here, it looks like it is IRB.

You can look into a BARTS test kit, they identify a number of different types of bacteria. The tests can take a month though.

IRB eats iron/steel, 70% of the Titanic is gone because of IRB. The guy that invented the BARTS tests used them on the Titanic. When a colony eats itself out of its food source the colony dies off and the iron content in the water will increase; until then it can decrease. Shocking the well can make the bacteria problem worse due to slime formation that chlorine can not penetrate due to the formation of encrustations. On well screen that will reduce the production of the well and the bacteria love the high velocity areas of screen. Adding chlorine to water raises the pH, that decreases the disinfection properties of chlorine. So IOWs, shocking can make the problem worse. If you look at the pH in that analysis, it is already way too high for chlorine to do much disinfecting.

Gary
Quality Water Associates

[rshackleford]

You are right. I think we are going to look into using Johnson’s NW410 pH buffer. I think that this will improve our disinfection in water wells. I started to look at our well and 90% have a pH higher than 8.0.

[Gary Slusser]

Yes that would help. Although I've never used any of this type checmical, research makes me think that Cotey Chemicals and Design Water has better chemicals.

Gary
Quality Water Associates

[rshackleford]

Please share that research. Help me out here. If we are make such a drastic change to our disinfection method and costing our customers more money I would like to be well informed.

[Gary Slusser]

Do a search for "Cotey Chemicals" and then "Design Water" with the "" and you'll find both of their web sites.

Gary
Quality Water Associates