What are the main problems in the traditional plug-flow activated sludge process? how to improve

Activated sludge process is the main method of wastewater biological treatment with activated sludge as the main body. Activated sludge process is a sludge-like floc formed after air is continuously introduced into wastewater for a certain period of time. It is inhabited by microbial groups, mainly bacterial micelles, which have strong adsorption and oxidation capabilities for organic matter.

The main problem is that the tank is linear, with one end being a water inlet and the other end being a water outlet. In operation, due to the high concentration of organic matter in the front stage and large consumption, the phenomenon of insufficient aeration in the front end and waste of aeration in the back end often occurs (low concentration of organic matter and low oxygen consumption). This situation can be controlled by measuring the dissolved oxygen index, as long as it is not lower than 2 mg/L, the oxygen supply at the back end can be reduced.