Fluoride Removal 1

[jsamora]

I have a small water system (200,000 gpd) of gw wells and I need to remove Fluoride and Arsenic. The FL is 11 mg/l and the Arsenic is about 0.025. I thought about Activated Alumina but that may be a problem with the FL above 2 mg/l. The pH is 7.95. Maybe Bone Char to reduce the FL, then AA or RO for the Arsenci? I know it is difficult. Any thoughts.

 

[Sanath]

11 ppm flouride is quite a high figure. Membranes may be your best friend. can you let me know where you are located?

 

[kenvlach]

See
Iron /Arsenic Removal Filter as Hand Pump Attachment
thread164-19003

Do you have analyses for [As⁺³] and [As⁺⁵], or just total [As]?
Also, what is the iron concentration, and is it +2 or +3? One method of As removal is as FeAsO₄.

 

[countryham]

Have you considered sodium sulfite to handle floride? and an anion resin to handle the Arsenic?

 

[kenvlach]

countryham,
I am only aware that sodium sulfite can reduce fluorine to fluoride:

^-2SO₃ + F₂ + H₂O = ^-2SO₄ + 2 HF

Kindly inform us of the reaction by which it handles fluoride.

I am also interested in information on arsenic removal via anion resin. Am familiar with traditional removal means such as oxidation and subsequent coagulation, e.g., as FeAsO₄, or adsorption on GAC.

 

[jsamora]

Thanks for the informatio folks.

This area is in Pojoaque, New Mexico which is just north of Santa Fe. The "Espanola Valley" has been know to have some high concentrations of fluoride.

The iron content was non-detectable.

No analysis on As ions.

 

[GarySCWSVI]

The right process for removal of Fluoride and Arsenic depends upon more than the data provided by jsamora. I highly recommend that jsamora contact a water treatment professional. Anion Ion exchange resins are one of the alternatives for both. The other technologies, except Sodium Sulfite, can also be used and depending upon the complete water analysis a combination of those may be required.

The following is excerpted from a web site at

http://www.eng-consult.com/arsenic/treat1.htm.

This web site has good information on the various technologies for As V removal.

"Ion Exchange with Brine Recycle. Research recently completed by the University of Houston (Clifford) at McFarland, CA and Albuquerque, NM has shown that ion exchange treatment can reduce arsenic (V) levels to below 2 µg/L even with sulfate levels as high as 200 mg/L. Sulfate does impact run length, however; the higher the sulfate concentration, the shorter the run length to arsenic breakthrough. The research also showed the brine regeneration solution could be reused as many as 20 times with no impact on arsenic removal provided that some salt was added to the solution to provide adequate chloride levels for regeneration. Brine recycle reduces the amount of waste for disposal and the cost of operation."




Gary Schreiber, CWS VI
The Purolite Co.

 

[kenvlach]

Thanks, GarySCWSCI, that's a very good summary of arsenic removal technologies. As you noted, proper selection requires complete analysis of the water.

 

[Muggle]

Suggest you contact Art Suma of AWS Consultants in florida - he has demonstrated high flouride and arsenic removal from phosphate mine wastewater with flows over 1million per day. He can be contacted at 813-655-9406. Email of DCHPAGE@aol.com