How to surge a home well. Odd well scenerio

[jd87n]

Hello, I would like to try to surge or jet my hand dug well. It looks like this.

4 inch casement pipe with many slits in it from angle grinder. Pea Gravel then dumped around annual area. At this point I learned my lesson about sand. (I didn't know about mesh sizes) and found out what I should have done. (proper mesh screen, etc)

I then bought a 2 inch pipe that has .010 screen that has 20x40 pre-pack sand around it and placed it in the rookie casement system described above.

Now I would like to surge it to try to remove the fines away from the casement area.

Can someone describe to me how would one surge a home drilled well. I dont get this description.

"By moving a surge block up and down the well, water is forced into and out of the aquifer, and mobilizing the fines"

How would I do that and surge a home dig well with normal tools and equipment.

thanks

 

[Valveman]

Without the proper equipment, surging is not easy. It takes a surge block and weight that will snugly fit in the casing. As a hoist truck rapidly pulls the surge block up and lets the weight pull it down, the up and down motion surges water through the slots.

You might get good results blowing with air, and it would be a lot easier for DIY.

 

[Sponsor]

 

[jd87n]

When you say blow with air, I just get a air compressor m connect it to a pipe and send as much air I can into to casing ?


Also this is a 100% sand area. Is surging even helpful when it’s all sand grains that are the same size. (I see where surging is helpful in other soil types)

Thank you

 

[Reach4]

1. Is the 2 inch pipe removable?
2. How deep is this well?
3. What is the static water level?
4. What is unsatisfactory with the well as it sits? Low flow, sand in water?

 

[LLigetfa]

You can quasi-surge by removing a lot of water fast for a short time, letting the level recover, and then repeating. Air lifting is one way and involves injecting air in the bottom of the 2 inch pipe. You could use a sewer jetter nozzle dropped down the 2 inch pipe or simply make your own.

If you have a high enough GPM pump, you could cycle it on and off while the output is unrestricted but that is not being kind to it as it can cause impeller uplift plus the abrasion of the material you are motivating. I did just that with an old pump that I was replacing anyway and by the end of my surging, the pump was no longer moving the same volume I started with.

 

[jd87n]

Yes the 2 inch is removable. The 2 inch sits in a 4 inch casement pipe with slits cut in then surrounded by pea gravel.

Well is 20 feet deep

Static well level is 8-10 feet

The issue is sand in the water even though it’s a .010 slot size with a 20x40 pack around it.

I don’t want to go to a .006 if I don’t have to.

One other question is what’s more effective? A .010 with a 20x40 pack or a .006 with no pack,

 

[Reach4]

What I would look to do is to hope the too-big pea gravel managed to catch some bigger pieces over time, and has slowed the flow of external sand. And that removing the accumulated sand in the 4 inch would be a big improvement.

To remove the sand, you can use a big engine-driven compressor to blow air down a 1 inch pvc pipe, and blow the sand and water out like a geyser. Impressive. Those compressors have a high rental fee.

The slower cheaper way is to use an air lift pump. A 4 to 8 cfm (if I remember correctly -- read up if you decide to try) electric compressor can power that, and you can lift sand and water out over a few days. There are a lot of Youtube videos. The key to an air lift pump is to have a good enough ratio of water above the lift point to the output of the pump. You would want at least 50% of the distance to be below the water level.

https://en.wikipedia.org/wiki/Airlift_pump

 

[Valveman]

The slot size depends on the size of the material you are filtering. If it is getting through a 10 slot, you may need an 06 slot. The 20x40 pack should help. But it may take quite a bit of development to get it cleared up. Don't really need a jet nozzle on the air line. Just an open ended pipe down 20' with a good sized compressor will work.

 

[Reach4]

Don't really need a jet nozzle on the air line. Just an open ended pipe down 20' with a good sized compressor will work.

Would that good sized compressor be 175 cfm, or 275?

 

[Valveman]

Shouldn't need much for 2" casing. I have never blown casing that small but I would guess a 50-75 CFM would work.

 

[Reach4]

Shouldn't need much for 2" casing. I have never blown casing that small but I would guess a 50-75 CFM would work.

He has a 4 inch. The 2-inch is a suction tube with a built-in sand filter at the bottom, and he can pull that for cleaning.

jd87n, whatever cleaning you do with a compressor, take photos!

 

[Valveman]

Ahh I think the 2" is gravel packed with the 20x40 sand? So it it just 2" casing?

 

[jd87n]

I sent a 4 inch PVC casing pipe with slits from a angle grinder down a 6 inch hole. I filled the the remaining 2 inch area around the 4 casement pipe with pea gravel. The idea was then to send a 1.5 or 2 inch pvc with a foot valve down the casing pipe. I was dumb enough to watch a few youtube videos to think this would work with out understanding much about anything.

After learning more and doing a sand analysis I went out and bought pre-packed pipe. Its a 2" x 36" PVC (2.8" OD) .010 Slot packed with 20x40 around the slots.

I then stuck that prepacked pipe in the PVC casing pipe hoping all would be good.

The ground water has to come through the pea gravel into the 4 inch casement pipe. Once inside the casement pipe it then filters through the 20x40 prepack into the.010 sloted 2 inch pipe.


Error number #2 was my sand analsys. When i sent in the sand I used what was coming out of the pump for my sample. But now that I have leanrd more the hard way I may have been drawing up the heavier sand from the bottom and not pulling the smaller particles as that results called for a .10 with a 20x40 pre pack.

At this point I am hoping that a well surge or developing it will take the sand away. However, I may just need a .006

 

[Valveman]

Yeah if that "prepack" isn't cutting it you just need a smaller "prepack" and slots. May reduce the amount of water you get though. I don't think you are going to do any good blowing or surging the 4", as that pea gravel will never stop the sand.

 

[Reach4]

The better deal may be to filter out the fine sand that makes it into the suction pipe up top. Shallow jet pump?

 

[jd87n]

Ok, thank you. To verify: a .010 with the 20x40 sand pack allows more particles in than .006 with no pre-pack.

I had this false assumption that pre-packs let you cheat. Meaning that a .010 with a 20x40 is a way to get a .006 filtration but with higher GPM flow then a .006 if that makes sense.

 

[jd87n]

Yes, shallow pump. I was looking at some of the particle filters like the Rusco but many of them said your suppose to put the filter only after the pump and not before. My desire is to save my pump from getting sand in it in addition to the sprikler heads

The better deal may be to filter out the fine sand that makes it into the suction pipe up top. Shallow jet pump?

 

[Reach4]

Lakos Sandmaster is made to go after the pressure switch and before the pressure tank. That requires the filter to be very-low restriction. It seems to me that maybe a better arrangement would be to have a pressure switch at the pressure tank, and another set-higher pressure switch before the filter. Pressure switches would be wired in series.

I don't know how these would work with suction pumps.

Valveman has observed that never having even a big course cartridge filter before a pressure switch is sometimes an over-cautious rule. See https://terrylove.com/forums/index.php?threads/how-many-microns.80850/ for some recent discussion on smallish manually operated backwashing filters that take out sand. I don't know how those would work with a suction pump either.

Right now, how often do you flush your pressure tank? Maybe with an increase frequency of that, the pressure tank could deal with your level of sand.

 

[LLigetfa]

Don't really need a jet nozzle on the air line. Just an open ended pipe down 20' with a good sized compressor will work.

My thinking is a jetter nozzle would work with a smaller CFM compressor. Since the total depth is just 20 feet, I doubt there would be enough lift with an open ended pipe blowing downward.

 

[Valveman]

Smaller CFM and a jetter nozzle turned sideways would stir up the filter pack. But you need enough CFM into an open pipe to get the well to blow. The Jetter would just restrict the volume.