Study On Shortcut Nitrification-denitrification In Two Steps A/O Biological Aerated Filter At Normal Temperature

In this thesis, using two steps A/O Biological Aerated Filter (BAF) realized accumulation of nitrite by controlling the experiment conditions at normal temperature. Shortcut denitrification came out in another anoxic column. It induced a new way to teat waste water with much nitrogen.DO is one of most important parameters for accumulation of nitrite. The results of this research indicate that the gas-water ratio 3:1 was suit for accumulation of nitrite. Change of pH may alter the amount of nitrite accumulation. pH between 7.0 and7.5 is suit for Nitrobater,whose activity may be slowed down with the increasing of pH.On the other hand ,pH between 7.5 and 8.5 is suit for Nitrosomonas. Increasing of ammonia loading which may influence ammonia removal is better for accumulation of nitrite. Denitrification can achieve above 75% at conditions that C/N is between 4 and 6, filtering velocity at a suitable area. pH influnced denitrification greatly.The velocity of denititrification slowed down with increasing of pH. But nitrite concentration took on increasing at first and droped at next.As a whole the suitable pH for denitrification is 7.0~8.0,beyond which, denitrification velocity may slow down.At low concentration (below 60mg/L), nitrite denitrification velocity is much more greater than that of nitrate.But this is not true at higher concentration :at 80mg/L,two kinds of velocity was closely. At the same condition ,the shortcut denitrification which began with nitrite can save carbon source about 30%.pH of shortcut denitrification effluent was lower than of full scale denitrification.The dynamics parameter of the shortcut nitrification-denitrification was gained by kinetics data analysis.The dynamics equation of the shortcut nitrification-denitrifica- tion as follows:...