Removal of nitrogenous compounds from aqueous solution by ozonation and ion exchange

Abstract

Experiments were conducted to investigate the ammonia, nitrite and nitrate removal from aqueous solution using ozonation and ion exchange. The operating variables of the combined ozonation and ion exchange processes include the pH, initial concentration of nitrogenous compounds and flow rate of aqueous solution. The effects of those variables on the removal efficiencies of the nitrogeneous compounds by ozonation, or ion exchange or both were explored. Ozonation was found able to completely convert nitrite to nitrate. However its capability of ammonia removal is much limited. The anionic and cationic ion exchange resins were able to efficiently remove nitrate and residual ammonia. An optimal operating range of OH for ammonia removal by the combined ozonation and ion exchange was obtained. However, removal of nitrite and/or nitrate by combined ozonation and ion exchange was found to be relatively insensitive to pH. It was observed that the combined process is capable of efficiently maintaining the nitrogeneous compounds in the aqueous solution at very low concentration levels.