Remove Fluoride from drinking water

[hockey1212]

I have the stats on a well in a rural area and need to devise a way to make the fluoride level safe to drink.

 

Assume I had to treat 1000 L per day and I wanted to get the fluoride concentration down to 1-2mg/L, how would I do that or show some calculations?

 

 

the details of the well im focusing on are:

 

pH=7.9

TDS= 975

[F-]= 13.1 mg/L

[CO3^2-]= 3.0 mg/L

[Ca2+]= 5 mg/L

 

 

 

 

I know I need to precipitate it but im not sure how to show calculations for it or what to use. Any help would be amazing.

[Hearts]

Flocculation. The Nalgonda technique (named after the village in India where the method was pioneered) employs this principle. Alum (hydrate aluminium salts) - a coagulant commonly used for water treatment - is used to flocculate fluoride ions in the water. Since the process is best carried out under alkaline conditions, lime is added; bleaching powder can also be added to disinfect the water. After a thorough stirring, the chemical elements coagulate into flocs that are heavier than water and settle to the bottom of the container. The operation can be carried out on a large or small scale, and the technique is suitable for both community or household use. One household version uses a pair of 20-litre buckets, with a settling time of one hour and not more than two hours: after coagulation and settling are complete, the treated water is withdrawn through a tap 5 cm above the bottom of the first bucket, safely above the sludge level, and stored for the day's drinking in the second bucket.

 

• Adsorption. The other approach is to filter water down through a column packed with a strong adsorbent, such as activated alumina (Al2O3), activated charcoal, or ion exchange resins. This method, too, is suitable for both community and household use. When the adsorbent becomes saturated with fluoride ions, the filter material has to be backwashed with a mild acid or alkali solution to clean and regenerate it. The effluent from backwashing is rich in accumulated fluoride and must therefore be disposed of carefully to avoid recontaminating nearby groundwater.

Both the community and household defluoridation systems have pros and cons. Defluoridation equipment connected to a community handpump is theoretically cheaper per capita than a household unit because of economies of scale; but ensuring proper maintenance of a commonly owned facility is often problematic, so good community organization is necessary. The household units are more convenient for filtering the small amounts of water intended for drinking only, and people usually take better care of them; but an extensive and efficient service system is required to ensure that the filters are replaced or regenerated at the right time. Technology is only part of the issue: local capacity building, including entrepreneurial capabilities, can be a far more critical and difficult task.

 

 

source: http://www.nofluorid...nicef_fluor.htm

 

First, list down all the pros and cons of each 'solution-to-the-problem' you find.

Next pick the most practical one in terms of effectiveness, cost, availability, speed of treatment...

Find out how fluoride reacts with (chemical-u-wanna-use) to form the precipitate..

From your equation balance, determine how much of chemical-u-wanna-use you'll need.

 

check out the section on 'jar test'

pg 39, section 3 fluoride reduction here

http://www.ijcea.org...s/72-B30028.pdf

the rest were 'too long didn't read' for me though.