7 month old 600' well has silt and sand still?????

[Reach4]

Jon, it is possible that you will pump less sand if you pump slower. It is possible to throttle a pump in a controlled manner. You might read some description of the effect of pumping more slowly in this thread despite some very significant differences: https://terrylove.com/forums/index....dvice-please-borehole-supply-in-the-uk.61806/

If you have occasion to replace your pump in the future, you might opt for a slower pump. If you are watering a few head of cattle and running a house, your needs will not be that great. If you are watering acres of iceberg lettuce, you will be pumping a lot.

 

[Valveman]

If you throttle the pump or use a smaller pump you will probably need smaller pipe. The velocity up the pipe has to be fast enough to bring the sand with it. Otherwise it just packs in on top of the pump and plugs off the check valve.

All areas are different. But it is nearly always possible to construct a sand free well. It just needs the right screen and gravel filter.

We always guaranteed a sand free well. And I had to redrill a few because they made a teaspoon a week.

 

[Sponsor]

 

[Boycedrilling]

Johnson Screens book "Groundwater & Wells" is basically the bible of the industry. I've had my copy of the 2nd edition since the 1980's. The 3rd edition came out in 2007. I finally bought this latest edition at the NGWA convention in December. It is this book that I am referring to with the following information.

Sand production in a well is a combination of various factors. First is the grain size of the water bearing formation. The second factor is the uniformity of size of the formation. The third factor is the velocity of the water movement into the well bore.

Grain size is the actual size of the particles. This determines the hydraulic conductivity of the formation. A clay formation may be completely saturated with water but will not have any yield or conductivity because of how small the grain size is. A course gravel will yield more water than a fine sand. If the gravels are coarse enough with no fine sand mixed in with it, a well might be successfully completed open bottom or with perforated casing. Smaller size material such as sands need a screen to retain and stabilize the aquifer. Sometimes the natural formation can be developed. A screen is installed that will retain 40-50% of the formation based on screen analysis. The well is then developed removing the 50-60% of the formation until it is stabilized and the fines have been removed for a far enough radius that the velocity of the water doesn't carry any additional fines into the well.

Sometimes the aquifer is too small a grain size to be naturally developed or there are other reasons to use an artificial sand pack around the well screen. The artificial sand pack still has to be sized to filter out the natural formation. Depending various factors, the artificial sand pack can be 3 to 6 times larger than the native material. If the artificial pack is more than 8 times the particle size of 70% of the native material, you are just about guaranteed to have a sand pumping well.

An artificial sand pack that is 0.250" will hold back natural material down to 0.08" to 0.04". This is 10 to 20 mesh screen size. If your native material is smaller than that, you need a smaller sized artificial pack material.

Entrance velocity of the water into the well is related to the diameter of the well and the length of the well screen.

Another factor is the amount of time invested in developing the fines out of the aquifer. I mostly drill larger diameter municipal and irrigation wells. Considerable time can be spent in the development of these wells. Of course I charge for this time. In the domestic well market, many times well development is included in the drilling price and the driller only spends an hour or two developing the well. Nobody is going to spend 10 or 20 thousand dollars of development time on a domestic well.

Another thing that can happen in well development is that you delelop the well, it quits producing sand. You stop the backwash of water then destabilizes the material and it starts producing sand again. It can be very frustrating developing fine uniform sand aquifers.

 

[Boycedrilling]

Yes, there is a way to scientifically quantify the sand production of a well. Roscoe Moss makes an instrument called the Rossum sand content gauge. It is basically a miniature cyclone that is plumbed into the side of the discharge of the pump. It is set to a specific flow rate thru the cyclone. Without digging out the instructions, it's a quart or two per minute thru the cyclone. It centrifuges out the sand that collects into a calibrated cylinder. You run water thru the tester for a specified time. You end up with a specific amount of sand per a set quantity of water.

I normally install this gauge on the discharge of any well that I test pump.

An unscientific method is to fill a five gallon bucket with water and see how much sand accumulates in the bottom of the bucket. This gauge costs $3 compared to the $500 Rossum gauge. Most domestic drillers feel they are done if there is a teaspoon or less of sand in the bottom of a bucket.

 

[Reach4]

Do you normally do the development with a different pump than the one that will be doing the producing?

 

[Boycedrilling]

Yes, I usually install a temporary test pump. Of course I don't do this for free. It will cost my customer any where from $750 to supply, install, run, and remove a 3 hp pump run for 4 hours to over $20,000 for a 500 hp line shaft turnibe pumping 1000's of gallons per minute for 24 or more hours.

 

[jon chilpigian]

Well we scheduled another appointment with the drilling company next Thursday now that we know there is probably a problem and this is not normal. Lets see what they say again?
Can you tell me anything I should be asking them that is of importance to the subject?
Thanks once again for everyone's feedback. I will let you know what they say next week. I'm not expecting to hear what we need to hear but you never know>

 

[Craigpump]

Sand Masters are ok, but I've replaced a few that were eating up by sand. If the sand will eat up stainless, imagine what it does to plastic impellors. Plus, they have to be drained off, either by hand or with a motorized valve assembly and timer. I'd rather have a Sub K over the pump and save the pump.

Normal amount of sand, here in the northeast every well is different just like people, so there is no "normal" per se. Some wells give up sediment, some don't. However, our water is fracture related rather than in an sand/gravel structure..

 

[PumpMd]

We have a river in our area with a bunch of wells around it, many well drillers have failed to keep the sand out of their well. This is where our 6gen well driller that we recommend must know some tricks because he guarantees clear water at 14.00 a foot, I have seen him help other well drillers out in this area. Pumping sand it not good on stainless steel impellers or plastic impellers, clear water is what you want.

 

[jon chilpigian]

Thanks again everyone for the input and info. They will be out Thurs to take a look again and give me their determination on the matter.

I do have a quick couple more question for my ammunition against them. For the drillers out there. I understand what everyone has been telling me about what could be wrong and that sand is definitely not a good thing to be coming up through the pump. But lets say they determine there is not that much sand coming up but we do know the water has brown tint to it. Cause it stains our shower and toilets and clogs my water filters in the house within a couple of weeks. Whos responsibility is to clean up that water? Is it mine to put a filter on the well or should it be automatic that when a well is drilled it is the responsibly of the driller to delivery clean water to the house?

And last, I noticed the other day that when my well turned on to fill my storage tank it took a good 45 secs to a minute before any water started coming out. and when it did there was a lot of air at first. Is there a check valve in the system that stops the water from going back down to the well and keeps the pipe primed? I never noticed on my last well it taking that long to prime?

Just curious on that last question whether or not I have another problem.

Thanks again everyone for the help!!!

 

[Valveman]

The sand or dirt you are pumping will also get under the check valve poppet and keep it from sealing. So every time the pump shuts off the drop pipe in the well drains to the water level. Then when the pump starts it will shoot a pipe full of air into the system. Letting the pipe drain back will further stir up the sediment in the well, which is not good.

Unless you got a contract from the driller stating he will supply sand free water, he doesn't owe you sand free water. But he does owe you a good job for your money. Drillers will usually work with you on things like this. But if you can't get any satisfaction, call the drillers licensing board to complain. You would be surprised how a call from the licensing board to the driller will help get your problems solved.

 

[jon chilpigian]

Great! Thanks Valveman for the info. That will definitely help out going into Thursday meeting with them.
I figured the check valve was probably sticking. And I will definitely keep that phone call in kind if I don't agree with what they say.

 

[Craigpump]

I've never seen a well contract that guaranteed the quality of the water, in fact most state that there is NO guaranty on either the quantity or quality of the water.

 

[Valveman]

I've never seen a well contract that guaranteed the quality of the water, in fact most state that there is NO guaranty on either the quantity or quality of the water.

We could never guarantee the quality or quantity of water in big irrigation wells because they were completed to get the maximum quantity, which means they may produce a little sand. But on house wells we completed them like a filter to keep the sand out. We always guaranteed a sand free well and had a written contract for that. Although a hand shake from us was just as good as a signed contract, but those were the good old days. I would never drill these days without a written contract. Times have changed.

 

[Craigpump]

98% of our wells are bedrock wells drilled into igneous rock, so we rarely see sand issues. We do see sediment from the fractures though which is easily handled by a whole house filter or in extreme cases a Sub K

 

[jon chilpigian]

Here's an update on the situation. So they came out this morning and checked the system for over 1 1/2 hours which I to me meant they were finding something wrong. They told me the check valve was bad and needed to be replaced. But as far as the sand they said it produced sediment/sand when it was first turned on but then cleared up. They are going to fix the check valve first and see if it draining back into the well is stirring things up and causing some of the sand. I guess I'm happy that at least they are doing something to try this time.
Question:
Since they are pulling the pump up for check valve should I go ahead and spend the money anyways and just have them put a Sub K on while it's up? Or do you think I should wait and see what happens after the valve replacement?

They did tell me that I should still put a 20 micron filter in the system on the feed to the house..

Thank You again

 

[Reach4]

Not as sophisticated as a Sub-K, a flow inducer sleeve might offer some of the effect for less money. Plus it helps cool the pump better if your casing is large.

 

[Valveman]

Not as sophisticated as a Sub-K, a flow inducer sleeve might offer some of the effect for less money. Plus it helps cool the pump better if your casing is large.

If the sand is heavy and settles easily to the bottom, an extra long flow inducer works almost as well as a SubK. But if you do either of these things you won't know if your well is still making that kind of sand until it fills the well to the bottom of the pump. Then you will have to have the well bailed out and still be having the same problem.

 

[Craigpump]

I've used 20' long pieces of 4" sch 40 before I discovered the Sub K, they work great but are hard to handle.

 

[jon chilpigian]

Well here's an update:
They came out on Monday and supposedly replaced 2 check valves. Unfortunately I couldn't be home to watch them do it so I'm having to take their word for it. It's going to be a week or so until I use up the water in my holding tank then I can clean it out again and see if I have instant water at the pipe and if we are going to have clear water? Keeping my fingers crossed on this one. I will update when I clean the tank out and refill.
I did not know they use 2 check valves in the well? Is that normal????