An experimental study was conducted to indentify the direct denitrification of ammonium nitrogen in culture water by ozone. During the experimnet period, pH was 7.8-8.8. pH was grdually lower after ammonium nitrogen was reacted with ozone under Br^-. In addition, it can be known that the culturing water was improved greatly form the inverstigation of T-N by biofilm and ozonation. As the results of a variation of recirculation rate, denitrification of ammonium nitrogen was in increased in proportion to the recirculation rate. But Nitrification of microorganism was opposite to the recirculation rate. With the increasing injected ozone in ozonation tank uner 21 circulation /day(6.7 ℓ/min), dinitrification of ammonium nitrogen was increased lineraly in propotion to the increasing of injected ozone concentration.

• 허목(제주대학교 환경공학과) | Mock Huh (Dept, of Environmental Engineering, Cheju National University)
• 임진숙(제주대학교 환경공학과) | Jin-Suk Lim (Dept, of Environmental Engineering, Cheju National University)
• 김부길(동서대학교 환경공학과) | Boo-GiI Kim (Dept. of Environmental Engineering, Dong-seo University)