Author/Authors :
Uemura، S نويسنده 1 Department of Environmental Engineering, Kisarazu National College of Technology 2-11-1 Kiyomidaihigashi, Kisarazu, Chiba 292-0041, Japan , , Suzuki، S نويسنده Nippon Steel Kankyo Engineering Co. Ltd., Chiba, Japan , , Abe، K نويسنده Nagaoka University of Technology, Niigata, Japan , , Ohashi، A نويسنده Hiroshima University, Hiroshima, Japan , , Harada، H نويسنده Tohoku University, Miyagi, Japan , , Ito، M نويسنده Ebara Jitsugyo Co. Ltd., Tokyo, Japan , , Imachi، H نويسنده Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan , , and Tokutomi، T نويسنده Kurita Water Industries Ltd, Tochigi, Japan ,
Abstract :
An airlift-type activated sludge reactor using a sponge support medium was fed with wastewa-
ter containing 500 mg-N/L of NH4
+
-N. In order to establish partial nitrification, the reactor was kept at 35°
C.
Moreover, the reactor was started up with the NaHCO3
solution as an alkali agent to supply inorganic carbon
for enhancement of partial nitrification. The partial nitrification was established during the period when
NaHCO3
was used as an alkali agent. However, soon after changing the alkali agent to a mixture of Na2
HPO4
and NaOH, the production of NO2
-
-N started to decrease. The change in pH inside the sponge medium
revealed by the model simulation and microelectrode study showed relatively high free ammonium concentra-
tion inside the medium. Thus, partial nitrification was proved to be affected by inorganic carbon in the alkali
agent. Furthermore, it was suggested that the establishment of partial nitrification in this study was due to the
combination of high operating temperatures, addition of inorganic carbon, and the inhibition of NOB by the
free ammonium concentration.
