What is the AO process in wastewater treatment? What are the characteristics and functions?

AO is the abbreviation of anaerobic oxidation. AO process is also called anaerobic-aerobic process. A (anaerobic) is used to remove nitrogen and phosphorus. O(Oxic) is an aerobic stage for removing organic matter from water. Its advantage is that it not only degrades organic pollutants, but also has a certain function of nitrogen and phosphorus removal. This is an anaerobic hydrolysis technology for pretreatment of activated sludge. The ecological sewage treatment equipment adopts AO processes such as anaerobic tank and biological contact oxidation tank to realize the harmless treatment of sewage.

Characteristics of AO process:

Because there is no independent sludge reflux system, sludge with unique functions cannot be cultivated, and the degradation rate of refractory substances is low;

In order to improve the nitrogen removal efficiency, it is necessary to increase the internal circulation ratio, thus increasing the operating cost. In addition, the internal circulating liquid comes from the aeration tank and contains a certain amount of DO, which makes it difficult to maintain an ideal anaerobic state in the A stage and affects the denitrification effect, and the denitrification rate is difficult to reach 90%.

The function is mainly to treat the sewage by grid well, regulating tank, sedimentation tank, AO biological treatment tank and other process facilities, so that the sewage can be purified.