Water Defluoridation: Nalgonda Technique

Product/Process

Process for removal of excess fluoride in ground water by using Nalgonda technique.

Application/Use

Safe drinking water with fluoride content within permissible limits of 1.5 mg/L for domestic and community use.

Salient Features of Process/Technology

Excess fluoride in drinking water causes dental and skeletal fluorosis. This water can be purified at domestic and community levels. The process comprises of addition of aluminium salt, lime and bleaching powder to the raw water followed by flocculation, sedimentation and filtration. The domestic level treatment is performed in a bucket or any plastic container. For community level, fill-and-draw type plants are used with capacity up to 400 m3/day.

Status of Commercialisation

Commercialised.

Minimum Economic Unit Size

Domestic level, cap 25 L/batch: Rs. 400
Community level, cap 400 m3 : Rs.5 lakh

Equipment and Machinery

FC/RCC setting tank, flash mix and pump, flocculator, rapid gravity sand filter and disinfection unit.

Raw Materials

High fluoride raw water, alum, lime, bleaching powder.

For further information please contact

The Director,
National Environmental Engineering Research Institute.