jack

Topic: Removal of fluoride.

Hello, 

I would like to have some information about removal of fluoride from waste water. I seem to have a hard time removing fluoride from my water. I have tried with calcium chloride, aluminum chloride mixes and lowered my concentration of fluorides in my solutions but the lowest i could get was at 12-15 mg/L and the city will soon regulate at 10 mg/L.

Are there any books or documents that can direct me in the right direction ?

Does anyone have experience with fluoride removal from waste water and can help me out ?


Thank you

Jack


DustinGebhardt

Re: Removal of fluoride.

It sounds like you are using the right treatment for the fluorides.  But because many fluorides compounds are slightly soluble, you will have to do what you can to drive the reaction in the favorable direction.  Probably the easiest thing to do is use a gross excess of the cation (calcium, aluminum, etc), which should drive the reaction toward the formation of the insoluble species.  I'm not intimately familiar with the kinetics of the reaction, so I'm unsure how strongly temperature plays a role or how much excess cation you will need.


You may also want to investigate using multiple treatment steps.  In vessel 1, treat as you normally do.  Remove the precipitate and pass the liquid on to the next vessel.  In vessel 2, repeat the treatment.  Depending upon the amount removed at each step, you may need more stages.

This method may require more upfront capital due to the additional reaction vessel, but it should cost less in chemical costs long term. 

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer

Moen

Sanford, NC

jack

Re: Removal of fluoride.

Thank you Dustin ! Much appreciated.

jimtrottier

Re: Removal of fluoride.

Jack:  I did a little research on this and found an article of others having trouble getting the flouride level below 10mg/L.  Go to google and type in: EPA-600/2-80-058

Or click here....

   Hope this helps.

    Jim

jack

Re: Removal of fluoride.

WOW this is great !!


Thank you very much Jim ! ill be reading it this weekend ill keep you posted :)