Читать книгу Groundwater Geochemistry - Группа авторов - Страница 58

The precipitation method involves certain chemical additions like calcium resulting in precipitation of fluorite; in the place of calcium, one can also use aluminum. One of the widely used Nalgonda techniques uses alum, lime, and bleaching powder with vigorous mixing, flocculation, sedimentation, and filtration. The method was initiated and developed by NEERI (National Environmental Engineering Research Institute) for community and household levels under Rajiv Gandhi Drinking Water Mission (Figure 2.5). The sludge obtained by this process has high aluminum and fluoride, disposal of which is also problematic.