9 - Filter media modification with nano-zero-valent iron to enhance nitrate removal efficiency during water treatment

Abstract

Application of nitrogen fertilizers and manures in agriculture, as well as the inland disposal of wastewater, resulted in excess nitrate in the soil. Due to high leaching property, about 50% of the applied nitrate infiltrate further into surface and ground waters. Elevated concentration of nitrate results in eutrophication of natural water bodies along with the deterioration of aquatic environment and drinking water quality. The removal of nitrate in water is seldom achieved in conventional water-treatment plants, which necessitates additional treatment unit incorporating the treatment methods such as biological denitrification, chemical denitrification, ion exchange, reverse osmosis, and electrodialysis. The methods like chemical denitrification and reverse osmosis necessitate an additional treatment unit for the nitrate removal from water. Therefore, convenient methods like adsorption and/or precipitation aided with coagulation are extensively used, especially in rural areas of the developing countries. The modification of these treatment units to enhance the inline nitrate removal could effectively reduce the cost and footprint of the treatment unit.