A district with endemic skeletal fluorosis plans household level defluoridation of drinking water. The Nalgonda technique, developed in India, removes excess fluoride primarily by adding which combination of chemicals?

• A Activated carbon and silver salts
• B Ferrous sulphate and potassium permanganate
• C Ion exchange resin and sodium chloride
• D Alum, lime and bleaching powder ✓

Explanation

The Nalgonda technique uses alum (which forms aluminium hydroxide flocs that adsorb fluoride), lime for pH correction, and bleaching powder for disinfection. It was developed by the National Environmental Engineering Research Institute and is suited to community and household defluoridation. Activated alumina is an alternative adsorbent, but ion exchange resins and oxidant combinations are not part of this technique.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.