NITRATE REMOVAL FROM GROUNDWATER

nitrate (NO۳−) is the most common groundwater pollutant on The planet and a seasonal surface water pollutant in active agriculture regions. Nitrate primarily originates from nitrogen sources used in fertilizers for crops, where it drains from fields into groundwater and surface water. It also comes from animal feed lot run off and land application of municipal sludge for nutrients. Nitrate is problematic because it causes methemoglobinemia in those with weakened immune systems and because it transforms to carcinogenic nitrite (NO۲ −) and N-nitrosamines in the human body Spalding. From an ecological point of view, the presence of excess nitrates in the water is one of the causes, along with phosphates, of the proliferation of algae, which reduce the oxygen content, and therefore contributes to the appearance of the phenomenon of eutrophication or even dystrophication of aquatic environments. From a healthy point of view, the reduction of nitrates ions to nitrites leads to the formation of methemoglobin (cyanosis disease) especially in infants (blue babies’ syndrome) which, following anoxia cellular, may progress to death. Its presence can also contributes to the synthesis of nitrosamines which may, in the long term, cause cancer of the stomach or intestines in adults, Ceica A(۲۰۱۱). Faced with these potential dangers, the WorldHealth Organization has adopted a threshold value of ۵۰ppm of nitrates (NO۳ -) equivalent to ۱۱.۳ mg / L of nitrogen (N), for water intended for human consumption, after which, nitrates become toxic, WHO (۲۰۱۱). Numerous methods have been developed to reduce the nitrate concentration in water like reverse osmosis, ion exchange, electrodialysis, biological denitrification, chemical denitrification and adsorption. All the methods have their inherent advantages and disadvantages. In the present study all the available methods are reviewed.