(227f) Physicochemical Denitrification Process for Drinking Water Resources at Ambient Conditions

Cost-effective removal of low level of nitrate in rivers and groundwaters for drinking water resources has been of considerable concern in developed countries due to its adverse effect to human health. It is also harmful for domestic animals. The decomposition and/or removal of nitrate in water is possible by using biological methods. This technology can treat a large volume of water at one time, but takes long time and large space. In addition, it will have to be followed by removal of bacteria and methanol or chemicals for hydrogen donors to utilize it as drinking water. Other technical option is to use a noble-metal-loaded catalyst and a reducing chemical such as hydrogen. The catalytic process will produce toxic byproduct or ammonia. A much more cost-effective and non-toxic alternative without any inconvenient side reactions needs to be developed for industrial and sustainable practice to remove nitrogen oxides. The present authors have invented a noble denitrification system totally different from the above traditional or conventional technologies. Acidic solution of pH 3.84 containing nitrate of 143 ppm was denitrified to a level of 0.6 ppm and simultaneously neutralized to pH 6.90. Operational features are: (a) processing time or contact time is <10min, (b) selective decomposition of nitrate/nitrite is feasible without side reactions to form NH3, and (c) it works at room temperature and at normal pressure. This noble process does not use (1) bacteria, (2) organic fertilizer or chemicals, (3) hydrogen gas, or (4) noble metal-loaded catalysts. This system will dramatically improve economy and time to denitrify water resources.