DE-FLUORIDATION OF WATER USING LOW COST AND LOCALLY AVALABLE RAW MATERIALS

Abstract

We all know that about 70% of the earth’s surface is covered with water. Most of the water is in the oceans (96.5%) in the unusable form and some of it is frozen (1.74%). Lakes, swamp water and rivers hold 0.014% and soil moisture accounts for 0.001%. Water also exists in the form of vapor in the air (0.001%) and as groundwater beneath the sub surface in the aquifers (1.7%). World’s water needs are met from the surface and groundwater resources. However, groundwater use is advantageous as it is comparatively fresh and widely distributed unlike the surface water. Threats to groundwater have been increasing everyday due to rise in population and demand of water. Thus with increasing demand of groundwater for domestic, industrial and agricultural needs, the pressure on this resource has become huge. Improper management and over exploitation has also lead to contamination of this resource. The degradation of groundwater may be due to natural or anthropogenic processes. Anthropogenic causes include contamination from wastewater from sewage treatment plants, discharge from industries, improper solid waste disposal, agrochemicals, runoff from agricultural fields, leakage from underground storage tanks etc. while natural cause are inherent geological conditions. When the chemical composition of groundwater is not within the prescribed limits for drinking or irrigation or industrial water, they become unsuitable. Arsenic, fluoride, iron, nitrate, manganese, boron, most heavy metals and radionuclides are few contaminants that are of great concern if not present within permissible limits. In my thesis, the causes and implications due to presence of increased fluoride in groundwater used for drinking purpose has been discussed. Also, I have discussed about measures to be adopted to mitigate the problem.