Sand in well water

[fliebig]

We have a shallow well (maybe 25') that is only used for watering the yard, etc. It's a 1 1/4" inlet to a 1/2 hp shallow well jet pump on a pad at the surface with a bronze checkvalve just before the pump. No tank.

Occasionally I get a fine sand through the hose, usually after shutting the water off at the gate valve outlet and then turning it back on shortly afterward. I tried running the hose into a 40 gallon trash can for several hours and got no sand in the bottom, so it pumps clean when left alone. The sand is clogging nozzles and eating the bronze bearing in my travelling lawn sprinkler. I have also used this well with my pressure washer.

My question is, is there any way to trap this sand before it gets to the hose? Or anything I can do to the well itself to cure this problem?

Fritz

 

[Bob NH]

Two possibilities:
1. Install a big cartridge filter with a 50 micron cartridge such as the HB-20-50W that can be hosed off when it gets plugged.
http://www.harmsco.com/pdf/IP_CalypsoBlue_FINAL_040904.pdf
Housings are about $50 + shipping and cartridges about $30 each.

2. Make a settling chamber with 3 pieces of 2" PVC pipe, 20 ft long, connected in parallel, and installed horizontally. Make provision for a drain so the sediment can be washed out.

 

[Sponsor]

 

[Speedbump]

With a 1/2hp jet pump, your not getting much more than 10 gpm. I like to use a 9"X48" softener tank, with an in/out head and 1" distributor tube. You add 50 lbs. of sand and it will trap the new sand coming through the line. A simple back wash manifold can be built with 1" ball valves, a couple of tees and some elbows. This will not diminish your flow and is easy to clean.

bob...

 

[Gary Slusser]

Here's another choice. IMO it requires the least maintenance of any choice.

 

[fliebig]

Thanks guys, you're advice is appreciated. Since I have to do whatever I'm going to do within a 32x40x18-inch box, I'll try the Big Blue filter solution first.

 

[fliebig]

Installation of filter

A couple more questions, if I may. There is only about 8 inches of vertical clearance on the horizontal run of pipe out of the well. I'll need about 12 or 13 inches to mount the filter housing vertically.

1. Can I pull the well pipe up 4 to 5 inches with a comealong without damaging anything down below? I've tried to find a well cap inside the 4-inch tile casing with no luck. I got only soil down to about 3 feet. This well is over 30 years old and located in Virginia. Is it possible that it was just backfilled after sinking it, instead of putting in a well cap?

2. Alternately, can I mount the filter at an angle? I don't care about spilling water when pulling the sump, but will the filter function properly if it's mounted at an angle?

 

[Bob NH]

The cartridge will work in any position. Getting the cartridge to line up may be a little work but there are alignment features in the top of the housing.

It looks like you have enough room to put the 20" housing horizontal in that pipe that goes to the left in your picture. Since you are outside you can use Schedule 40 PVC fittings available from HD or Grainger as well as plumbing supply stores.

The housings are available with 1" female threads.

 

[fliebig]

Thanks Bob,

The well pipe is 1 1/4", so I was planning to order a 1 1/2" version of the 10" housing and use a couple of 1 1/2" - 1 1/4" nylon bushings to fit it into the line.

Speedbump (bob) mentioned that my 1/2 hp jet pump will deliver about 10 gpm, which seems about right. You mentioned that a 20" housing with 1" female ports might fit. Would getting the (more expensive) 20" housing (30 gpm) buy me anything over the 10" housing (15 gpm)? Shouldn't I try to keep my flow path at 1 1/4" to maximize flow if I can?

I'm planning on using a 50 micron pleated polyester cartridge as you suggested. Given that this is a pretty low-tech DIY-type application (and that I've bee accused on occasion of being kinda tight), is there a significant advantage to using the Harmsco cartridge over another manufacturer's brand, or can I go with the best bargain?

Please forgive all these questions. I'm new, and am learning a lot here.

 

[Bob NH]

Doubling the size of the filter will increase the life of the filter by a factor of 3 or more (theoretically factor of 4). Double filter size cuts flow rate per unit area by 1/2 and doubles the surface area to collect dirt, so 4 times as much water/dirt to reach the same pressure drop. Bigger filter usually means lower life cycle cost.

Any 50 micron filter that fits the Big Blue housing should work. The pleated paper or polyester filters provide the most area per cartridge. You usually need to change the cartridges when the differential pressure is about 20 psi.

I get generic Big Blue housings from Applied Membranes http://www.appliedmembranes.com/ but if you want only one they send you off to a retail site and charge full price. Same situation with Harmsco. The Harmsco cartridges are usually sold in packs of 4.

At 10 GPM you aren't going to have much different pressure drop between the 1" and 1 1/4" housings. If your dischrge pipe is 1 1/4 then stay with that. The filter must go on the discharge side of the pump or the pressure drop will kill the pump flow.

 

[fliebig]

Well, I'm glad we had this talk, because I was about to commit a major blunder. The 1 1/4" pipe is on the suction side of the pump. the discharge is 3/4". I'll look at a 3/4 or 1" x 20" housing now & rethink this.

Thanks again.

 

[Bob NH]

You should be aware that most 3/4" fitting housings are not "Big Blue" housings. "Big Blue" is an Ametek brand name but others sell generic housings that take the same cartridge. A small diameter housing that takes the 2.5" diameter pleated cartridges has less than 1/2 the surface area of a Big Blue housing of the same length.

 

[Gary Slusser]

The Big Blue uses 4.5" dia cartridges and comes in 10" or 20" long models with 1" or 1.5" inlet/outlets. Any local water treatment dealer and many plumbing or pump supply houses can sell you one along with the cartridges. IIRC you can stack 2 4.5" x 10" cartridges with a coupler.

As to the sand, a 3/4" in/outlet head on a 10" clear housing with no cartridge in it would probably stop the sand problem. And you'd empty the housing periodically rather than spending money on cartridges. And maybe if you watered for a shorter period of time, the well might not produce sand to start with.

 

[fliebig]

As to the sand, a 3/4" in/outlet head on a 10" clear housing with no cartridge in it would probably stop the sand problem. And you'd empty the housing periodically rather than spending money on cartridges. And maybe if you watered for a shorter period of time, the well might not produce sand to start with.

The empty housing idea sounds attractive. I can get those all day long at the local home improvments stores. I've located a 1" Big Blue 10" housing at a local plumbing supply house for $70 & have also found them on the web in the $50's. No-one around here stocks the 50 micron cartridges though.

It seems like it only pumps sand when I shut the spigot and reopen it while the pump is running. As I mentioned in my original post, as an experiment, I ran it for several hours into a large plastic trash can and got no sand at all. But if I shut if off to change sprinklers or nozzles and turn it back on, the sand screen on the sprinkler/nozzle inlet clogs up shortly afterwards.

I remember seeing a segment on This Old House where a well driller talked about running the well wide open for a few days to create a hollow at the bottom of the well and thus prevent the well from pumping sand. That's why I wondered if there was something I could do to the well itself to cure this. I'm assuming my little 1/2-horse jet pump will not get it did.

 

[Bob NH]

I was in a HD store to day and they have a 10" Big Blue size housing, GE brand, for $50. They also had 30 micron 10" long cartridges for about $14 each. The difference between 30 and 50 microns is not significant.

The cartridge will not have much effect on the sediment collection. If the housing is going to collect sand, you should get sand in the bottom of the housing. It will work better as a sediment collector if it is installed horizontal.

 

[Gary Slusser]

The housing should be installed vertically as they are designed to be installed. The water enters through the head toward the bottom of the sump and exits vertically in the center of the head.

This Old House should stick with remodeling houses, sucking sand through a pump eats pumps really quick. If they want to clear sand in the bottom of a well they should suggest cleaning the well but.. you can't keep sand out of a well that is allowing sand in becasue the supply of sand is never ending.

IMO you should water for shorter periods of time and water with less flow while watering. Your pump should not have the check valve at the pump, there should be an operable foot valve on the end of the drop pipe. The sand problem could have something to do with a leaking foot valve stiring the sand up when shut off the water. Are you sure you don't have a hand dug well instead of one with a casing?

I'd go a regular $20 filter housing outside the box and see how it worked before I'd spend more money on a Big Blue.

 

[Glen4cindy]

Can I add a question to this?

My well seems to be sucking sand all the time. Let me give some background and what I have tried and we'll see if any of you have any advise.

When I first had this well installed, the guys came and water jetted the bore hole. They finished up by installing a pipe they had glued up before they came. It was a 2" PVC pipe with a PVC Point at the bottom. I think that at some point before they left, they fractured the 2" pipe because it turns freely at the top of the well when I am attaching the top connection.

I never could get this setup to hold prime. Tried several things. So, I then decided to consider the 2" PVC as a casing, and inserted an 1 1/4" pipe inside the 2" pipe, connected to a check valve and then the pump.

This setup seems to work fine except that sand plugs my sprinkler heads. It also seems to have ruined a check valve. I tried using a pressure washer fed from this well and the inlet quickly plugged with sand. That was last year. This year, I pulled the 1 1/4 pipe, and put a fine screen inside the foot valve and replaced the ruined check valve. At the beginning of this season, the well pump kicked on and ran for a couple of hours without pumping any water. I think it blew a seal somewhere, but, it still pumps so I am using it until my seal and gasket kit arrives. After running the pump for several hours watering my lawn and turning the pump off, there is fine sand under the pump where the water runs out of the housing.
Now, I have pulled the 1 1/4" pipe higher in the 2" pipe, but, I am still sucking sand. Someone suggested that I take a length of pipe at the bottom of the well, and drill several holes in it, and secure cheese cloth type material at the bottom of the pipe to screen out the sand. I am at my wits end on how to deal with this sand. I would like eventually to feed an underground sprinkler system with this well, but, cannot until I deal with the sand.

Does anyone have any advice? Should I remove the foot valve and drill holes in part of the bottom of my suction pipe and right above the pipe where the holes have been drilled, place a brass check valve to keep prime?

Thanks for the help!

 

[Speedbump]

Think of it like this. You put the cheesecloth on the pipe with the holes. The sand has nowhere to go, so it will fill up around the cheese cloth and choke of the pumps ability to get any water.

The only thing that will fix the sand problem is a pipe without any split in it or a finer screen depending on which is the actual problem.

I would call this driller/washer back and have him make it right. Wells are not supposed to pump sand.

If you can move this 2" pipe, maybe you can pull it and inspect it. If no splits are evident, the screen is too course for the sand.

bob...

 

[Glen4cindy]

Thanks for the info.

Calling the installer is not really an option because I think I hired the wrong person to do it in the first place. He only water bored the hole and inserted the pipe. The rest, pump, check valve, etc. was up to me.

I am afarid to try to pull the pipe in fear of collapsing the hole, or, if there is a fracture, I could lose part of the pipe in the hole. Also, if the pipe does not easily slide back into the existing hole, I don't have the know-how to get it back in.

Do they make a 1 1/4 point that I could put at the bottom of the suction pipe I have inside the 2" PCV pipe?

Also, just because it is obvious that most here know more than me, in regard to the cheese cloth getting clogged, I have thought of that. What keeps that from happening to a well point? Also, I have been told that using the well will create a large cavity near the bottom of the point that will be full of water. Is this true? If so, is it possible that my well does not have this large cavity?

Thanks. I really need the help because as I said, I am not knowledgeable about this at all. I have learned because I have had to!

 

[Speedbump]

Cheesecloth has far smaller holes that a well point does. The trick it to size the screen to the sand in the water vein. He obviously didn't do that, since the screen was already on the pipe before he arrived.

If you don't pull the pipe you still have the problem.

Just because you hooked up the pump doesn't mean the well guy is off the hook. The well should not pump sand.

Putting a screen down into the two inch will not work either. The screen has to be in the water vein so water can flow to it. When you fill the pipe in the well with sand you will only have a 2" opening for the water to filter through into the screen. You may get a teaspoonful per minute.

bob...

 

[sandywater]

Another option

I had a similar problem. Lots of sand in the well. Ran the hose into a bucket and let the water dry. The sand that remained was a pretty good amount, not fine like dust but big like beach sand.

Installed a cartridge filter for $50, but it was costing me $30 every time the cartridge filter element needed replacing. Bought a spin down filter and put it in front of the cartridge filter.

It's been 2 years, and the cartridge filter still hasn't needed maintenance. When the spin down filter gets dirty you open the valve on it and it clears right up. Got it at home depot for about $40. Called a "Orbit 1-1/2 in. Sediment Filter" there.

The spin down doesn't get the really tiny stuff though, but it catches most everything. It's a great prefilter, cleans itself never need replacing any parts.