Main influencing factors of biological nitrogen removal process

The suitable temperature range of biological nitrification is 20~30℃, and the nitrification rate decreases below 65438 05℃ and basically stops at 5℃. The suitable temperature range for denitrification is 20~40℃, and the denitrification rate decreases below 65438 05℃. In practice, it is observed that the denitrification process of biofilm is less affected by temperature than that of suspended sludge process. In addition, the denitrification temperature sensitivity of fluidized bed is much less than that of biological turntable and suspended sludge.

(2) Dissolved oxygen

The concentration of dissolved oxygen in the biological nitrification reactor should be kept above 2.0 mg/L.

(3) pH value

Nitrifying bacteria are very sensitive to pH changes, and nitrite bacteria have the best activity at pH 7.0~8.0. Nitrifying bacteria have the best activity when the pH value is 7.7~8. 1 When the pH drops below 5.5, nitrification almost stops.

(4) Carbon-nitrogen ratio

(5) Mud age

(6) Toxic substances

3. Biological denitrification process

At present, the widely used biological denitrification processes mainly include SBR process, oxidation ditch process and anoxic/aerobic (ANO) process.

ANO process is short for anoxic/aerobic denitrification process, where A is anoxic and O is aerobic. The process flow of ANO method is shown in the following figure.