Dr Raaz Maheshwari*, Sangeeta Parihar
Department of Chemistry, SBRM Government (PG) College, Nagaur, Rajasthan
Department of Chemistry, Jai Narain Vyas University, Kodhpur, Rajasthan
Clean drinking water is one of the most essential commodities enjoyed by human beings. Fluoride in excess of 1 mg/l in water causes fluorosis. Compared to surface water sources the ground water sources contain fluorides as high as 44 mg/l. The problem of fluorosis is prominent and endemic in many parts of the world as well as in India. Although various defluoridation methods are available, in Indian context the Nalgonda Technique has been mostly adopted. Alum is used as the coagulant in this process. It has some disadvantages like high sludge volume, residual aluminum, wearing effects on the treatment structure. Therefore, an alternative to alum for defluoridation assumes importance. The main problem of the Nalgonda Technique is the residual Aluminum in treated water which at times is found to be higher than the permissible limit, i.e. 0.2mg/L. We aim to reduce the use of Alum by bringing down the fluoride level firstly with Moringa Oleifera seeds powder and then using Alum later on. For reduction from low fluoride levels less Alum will be required as compared to reduction from high fluoride levels and hence, we would be able to reduce the residual aluminum in the treated water. Apart from solving the residual aluminum problem, coagulation by MO seeds solves the sludge volume problem also as it produces less amount of sludge for the same amount of removal in comparison to Alum.
Keywords: Nalgonda technique, Defluoridation, Alum, Aluminum, Moringa oleifera, SRF, Polyelectrolytes, Alkalinity