Silica removal?

[RomanSantangelo]

I have to treat 1200 m³/day of raw water from a well, with a content of about 135 ppm silicate expressed as CaCO3. I have to reduce its content to 10-15 ppm before an ultrafiltration treatment.I know that is possible with a flocculation with MgO but till now I haven't practical experience of it with this flow rate.
It must be mentioned that this raw water has a high conductivity (1500 microsiemens). What can you suggest me to reach a good result?

 

[aspearin1]

I was working on a similar problem not too long ago (didn't really pursue the solution). I was informed to try anion exchange beads, if the silica is dissolved. As far as flocculation goes, I've been toying with a polyacrylamide flocculant from Tramfloc, Inc. They do have strong cationic forms.

http://www.tramfloc.com

Hope it helps.

 

[RomanSantangelo]

Thanks aspearin1, yes I have the silica dissolved, but if I have a high contents of salts I must to back-wash the resins very often, that's right? So to obtain 1200 cubic meter/day I have to pump from the well a lot of water much. Tell me if I wrong.
You have chosen the solution with flocculant, what are settling characteristics of the sludge you have obtained?

 

[aspearin1]

The settling characteristics are all dependent on the size and density of the particles you're trying to settle out. I am actually working with very light dissolved particles, so the settling is only due to the flocculant itself falling out of solution. How often you need to regenerate your ion exchange beads all depends on your flow and content, including other anions that will compete with silica removal. This is why anion exchange beads was not an option for me. I had too many anions in solution that prefered ion exchange over silica. You really need to run some lab tests to determine if the exchange beads will work for you.

 

[kenvlach]

I suggest you post your question at the Water treatment & Distribution Forum, lots of experts there.
My experience with silica removal via IX is that it is the first anion to 'break through,' in agreement with aspearin1's comment.