The National Environmental Engineering Research Institute (CSIR-NEERI) developed an indigenous and economically viable process to reduce high fluoride content in potable water, which would have a domestic and community applications.The chemo-defluoridation of potable water with high fluoride content is achieved in collaboration with the Mumbai-based Rajeev Gandhi Science and Technology Commission, and can be used for reduction of fluoride concentration from 5-8 mg/L to < 1.0 mg/L (miligram per litre). The process does not affect the palatability of water.
According to a NEERI release, a chemo-defluoridation domestic unit consists of a steel container fitted with a sand filter at its bottom.In order to reduce the fluroide content, a fluoride bearing water (30 L) is added in the container followed by dosing of the salts of calcium and phosphorous chemical coagulants with manual stirring.
When these salts are added to the fluoride-bearing water, they gradually get dissolved and precipitated absorbing fluoride from water.
The water along with the residue is then passed through the sand filter to get the treated water with fluoride less than the permissible limit of 1.0 mg/L, the release said.
It further said that efficiency of the filter is reduced roughly in a month due to settling of chemical precipitate on the sand filter which can then be manually cleaned by removing the top layer of the precipitate settled on the sand bed.
The cost of the household unit is about Rs 2000 and the treatment cost incurred is around 20 paise per litre. The units are suitable for the small fluoride-affected villages where community water supply schemes are not economically feasible, the release said.
The release informed that 30 household defluoridation units have been distributed in Chichkavatha village in Nagpur district in collaboration with the Nagpur Zila Parishad, Sonegaon (Lodhi) Gram Panchayat and Bharat Nirman Cell, Nagpur.
There are 30 houses and two hand pumps in the village where concentration of fluoride is in the range of 1.8-1.9 mg/L (mg per litre). In India an estimated 60 million people are affected by drinking water from well with excessive fluoride content.
The effects of excessive fluoride typically manifest into Bone deformations of children, while in high proportion, soluble fluoride salts are toxic and skin or eye contact with them is dangerous.
Meanwhile, a demonstration about the usage of the domestic unit was yesterday given at Chichkavatha village where the NEERI officials apprised the villagers about the ill-effects of high fluoride content.
After successful field performance of 80 units installed in Sakhara village in Yavalmal district in 2010, this is the second village where the units have been set up.
Experts also informed that the chemo-deflouridation units will be installed in other fluorosis endemic habitations with support from Maharashtra Water and Sanitation Department and other agencies.
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