Removal of Nitrate from Drinking Water-A Review

Abstract

The  concentration  of  nitrates  in ground  water  is observed  to  be  increasing  in  the  world  in general  and  Asian countries  in  particular. Ground  water  is still  a man source  of  drinking  water  especially  in rural  areas  of  Asian countries.  Nitrates  are known to  cause methaemoglobinemia  in babies and intestinal  cancer due to formation of nitrosamines  in general  population. Several treatment  processes  for the  removal  of nitrates  from  drinking water have  been  studied.   These  processes  comprise;  vegetative   de-nitrification,   reverse   osmosis,  electrodialysis, catalytic  reduction,  chemical reduction,  ion exchange  and biological denitrification.  Combinations  of two  methods like  combined  ion  exchange-biological  denitrification   have  also  been  studied.  Every  method  have  merits  and demerits,  however,  the methods  based  on  ion  exchange  for  the  removal  of  nitrates  from  drinking  water  and regeneration of  resin  by  biological  denitriflcation  appear to  have edge  over  other  methods.  This  communication presents  a review  on existing denitrification processes  and spells out needs for future research.