Removal of Nitrate Nitrogen from Groundwater by a Combined System of Erectrodialysis and Biological Denitrification

摘要

Groundwater purification by nitrate removal system which consists of electrodialysis and biological denitrification was examined. Results showed that it was effective to manage the nitrate Concentration of electrodialysis effluent by measurement of electric conductivity. And, it turned out that the ratio of methanol addition to a denitrification tank was 1.9 g/g removed NO_3-N. This value was almost the same as the theoretical value. The system delivered in December 1999 to a water purification facility in Nagasaki has been operated successfully. The quality of treated water over about two years proved that this system had the stable nitrate removal performance.