need filter system for very fine silt

[EmilyS]

I'm on a well that produces a lot of sand and fine bentonite silt; it goes through the standard small whole house filter as well as a Lakos separator and gets into my appliacnces. The only solution suggested by local plumbers is an expensive ($1500 installed) multi-stage filter sort of like a water softener as I understand it

The smallest off the shelf filter I can find is 2 microns, but it cuts water flow considerably. An expert at the state engineers says my silt is probably smaller than 1 micron.

Is there a simple, less expensive filter system I can use?

[Andy CWS]

Well, I am not so sure that a multi-media filter will help that much. The human hair is about 80 microns, the human eye can detect about 45 microns. At 2 microns, the 'sediment' will be invisible to the naked eye.

What size filters are you using? A multi-media filter will filter down to about 20 micron and maybe with some media down to 3 microns. So that would not be any better than a small 2 micron filter if that filter is not doing the job. If the 2-micron filter IS doing it then a backwashing filter would be better even at that cost for convenience and service. Small filter will clog up too quickly and your pressure will be lost.

Ceramic filters can filter down to 0.9 microns.

You may need an ultra-filtration device which can filter much finer but cost is higher. You may have colloids.

Looking for something less expensive? Not likely to do more work for less money, that's everyone's dream.

Andy Christensen, CWS

[EmilyS]

thanks, Andy

I have used 5/10/20 micron filters and am how using a 2 micron filter... even with that, if I rub my finger along the gaskets in my dishwasher, I can feel and see the very fine silt. Individual grains, as you note, are invisible, but they do accumulate to the point that I can see them.

If the expensive backwashing filter is the only thing that will work, I'll spring for the $$$$ (or actually use this info to fight with the builder about who should pay).

I would like to know if there are any other solutions.

[Andy CWS]

Another solution may be a flocculation/coagualtion system. This is where and chemical feed pump adds an alum solution to the water, then into a retention tank and then into a filtering system. The alum takes particles, making them bigger by combining them so that a filtering system can remove them.

We use this for surface water treatment and colloids.

This will work but try other, less expensive solutions first.

Andy Christensen, CWS