sulphate removal technologies from drinking water

Sulfate which is a combination of sulfur and oxygen (SO4) exists as a dissolved salt in the water. As such it is colorless and odorless. It is not to be confused with the gas in the water that causes a rotten egg odor. This is a combination of Hydrogen and sulfur (H2S). Removal technology is totally different for the two forms of sulfur.

Sulfates: The US Primary Drinking Water Regulations list safe levels of sulfates at 500 ppm (mg/l) in drinking water and Secondary Drinking Water Regulations for sulfates at 250 ppm (mg/l). At this level or above, sulfates can cause diarrhea and resulting de-hydration. This condition is most severe in infants, the elderly, and people with other illnesses. Also, high sulfates cause fluid and resulting weight loss in all animals

Sulfate can be precipitated by addition of lime, calcium chloride

or removed by anion exchange resin. those waters where high sulfates (>250 ppm) are to be removed by Purolite^® ion exchange. High levels of sulfates have been known to cause diarrhea in humans and animals. Purolite Strong Base Anion (SBA) exchange resins, operated in the chloride form, can remove these sulfate ions. In addition, high sulfate levels are also a concern for Reverse Osmosis (RO) membrane fouling. At high concentrations, they precipitate on the membranes and reduce the efficiency. These Purolite® resins are regenerated with brine. As Purolite anion resins, they use the chloride portion of the NaCl. During the service run the sulfate ions displace the chloride ions due to the higher selectivity of the Purolite Strong Base resins towards sulphate ions.

 

Rather than waste either the sodium or the potassium we place the special sulfate resin on top of regular softening resin and along with removing the sulfates we also soften the water with the same amount of salt being used. We get a free bonus of softening.

Maximum Iron and Manganese Levels in water :

Combined Manganese and Iron levels must be below *0.8ppm

*A resin cleaner is to be used at these levels to help prevent premature resin failure due to iron buildup.

source : public health engineering...by nemero