well now has some sand

[jeano]

Have a question
Our well is 52 meters with a pipe that is 5 inches on the inside. We have a submersible pump- 3 hp- high volume- low pressure. We use this well to fill a pond and irrigate from the pond. The well has developed some sand. Is there a filter or what can anyone suggest? Have tried all sources in Costa Rica for answers- The only suggestion is a new well.

Thank you

Sandy

 

[Artisi]

First-up you will need to establish WHY you have sand in the well.

Is the well fitted with a proper well screen to keep the sand out or is it simply a pipe with holes wrapped in a sreen cloth, was the well professionally installed - how long has it been in service etc etc.

 

[jeano]

Have you used the Lakos PPS ? Are there other brands?
Since we are in Costa Rica- anything we buy will not be returnable- the logistics are a minor nightmare at best but we would purchase and ship a Pump Protection Seperator. None of the well drillers or companies selling submersible pumps are familiar with this type of equipment. It is very difficult to find people who are knowlegable about the products they are selling such as submersible pumps- PPS seems to be totally out of their sphere of knowledge..
Yes the pump is encased in a mesh

Sandy

 

[BRIS]

you say that the pump is encased in a mesh which implies that your well is an open hole with no screens.

1) what is the concern with pumping sand - pump life?

2) You could try and fit a casing into your existing well - the solution depends on where the productive aquifer layer is and how much draw down you get when pumping (you will get more when you install a casing) and the diameter of your pump. If draw down is small you may be able to install a 3 to 4" screen in the well below your pump and case the well from the pump to the surface. The screen comprises slotted pipe with a slot width smaller than the sand grains to act as a filter.

Drilling a new well or reaming out your existing well and fitting screens and casing is probably the solution. You would need to consider the cost against the disadvantages of pumping some sand ?

 

[thewellguy]

I have used the lakos filters. About a year ago we in installed 15 of them on different wells and so far so good. This is my only experience with the. I do know that there are different filters depending on the amount of water the pump is moving so make sure you get the volume to match the filter.

Another idea that may or may not be an option is simply reduce the volume of water you are pumping. The slower the water is moving the less sand that will be pulled into the pump.

 

[FACS]

I agree with wellguy about the pump size. 3 hp, large volume-- sounds like a lot for only a 5-inch well casing.

Also, perhaps the pump is too close to the bottom. Usually, a well is drilled to the water depth, and then drilled deeper so that the pump is not at the top of the water line nor at the bottom of the well.

Sand filters may still be needed as the sand will soon displace all the water.

Charlie

http://www.facsco.com

 

[stonetech]

Reducing the sand to the pump using perhaps a basket strainer or y-strainer might help if it does not reduce the pressure drop to the pump that may Affect the NPSHA..

Beyond that, you might consider another type of pump such as a slurry pump?

 

[BigInch]

"Better to cure the disease rather than treat the symptoms." Artisi mentioned you need to determine why you now have sand. Have you changed the quantity of water you're drawing lately? Has the aquifer changed? As was also mentioned above, I think you have high power for 52 m head, so flow might be very high at 300-500 l/s??? If that's the case, then I also think the velocity of the water is very high and and its effects may be damaging to the aquifer. If you want this well to last, you really must determine if you are just drawing a little sand off the bottom, or if you're pulling from the aquifer. I suspect the later. If you are pulling from the aquifer, eventual collapse or plugging may be a possibility. What is the water flowrate and the sand pull rate now? You might want to monitor and record those figures to see what is happening with the sand to water flowrates. It might give some indication as to what you may be doing to the aquifer. In the meantime, slow down.

http://virtualpipeline.spaces.msn.com

 

[chief]

This is an off the wall solution, but may be worth a try. When you drop your pump into the well, strap on a hose to your pump tubing, to end inside the suction filter mesh. When the mesh chokes with sand , back flush out from a surface water supply.
Have used this method in dire circumstances previously, it will get you back on line rapido.

Offshore Engineering&Design