Study on Variation Characteristic of Nitrification Rate of Activated Sludge in A~2/O Type Oxidation Ditch Process

The nitrification rate is a key indicator reflecting the nitrification activity and capacity of activated sludge,and it is influenced by many factors.The nitrification capacity of activated sludge and its variation in A~2 /O type oxidation ditch process at different temperatures were studied in the static tests. The results show that when the sludge age is unchanged,temperature is the most important factor affecting the nitrification rate and capacity of activated sludge.The nitrification rate is reduced with temperature declines.The nitrification rate is 4.0 to 6.0 mgNO_3~- - N/(gVSS ? h) at 20 to 30 V,,and it is reduced to 2.0 to 3.0 mgNO_3~- - N/(gVSS ? h) at 10 to 16℃.