In Nalgonda Technique of deflouridation addition of the _______ in following sequence:
Nalgonda technique was developed by the national environmental engineering research institute (NEERI) at Nagpur in 1974. The process comprises Addition in sequence of sodium aluminate (filter alum), lime and bleaching powder to fluoride water followed by flocculation, sedimentation, and filtration. The technique is extremely useful for both domestic as well as for community water supplies.
Alum,lime, bleaching powder.
Lime,alum, bleaching powder.
Bleaching powder, alum ,lime,
Bleaching powder,lime,alum.