Studies of Denitrification of Nitrate Nitrogen by Utilizing Porous Ceramics Balls with Immobilized Bacteria

The earth has a huge ecological system, metabolism. Environmental pollution has been alarming that the natural equilibrium between anabolism and catabolism is under destruction which will never fail to cause infinite and irretrievable damages to human beings. Water pollution of nitrogen species both in underground and on the surface of the earth is one of the representative problems causing severe diseases such as cancer and methemoglobinemia. In the present, many kinds of treatment for denitrification in physical chemistry or biology are challenged to solve water problems. These methods are, however, unavailable for applications because of difficulties in theory and in practice as well. In this study, a biological method is applied to remove nitrogen species from the water polluted by nitrate nitrogen. In our case, bacteria, their names as yet unidentified, were derived from the humic soil and cultured. Bacteria were immobilized in porous specific ceramics balls to which Graphite Silica, mineral, and Shirasu, vitric volcanic material, are burned. Graphite Silica has a specific peculiarity. It radiates middle-ranged infrared ray almost identical to black-body radiation. Using the immobilized bacteria, continuous experiment of denitrification was performed in the heterotrophic condition with a small amount of organic carbon as the nutrient. The concentration of nitrate and nitrite is successfully attained within 1mg/ℓ (1ℓ=1dm^3) through our denitrification system that requires small costs of operation