What factors affect the operation of biochemical systems？

The operation of the activated sludge process requires reasonable regulation of many control parameters, including the control of activated sludge concentration (MLSS), which is one of the most commonly used indicators in the daily operation of sewage systems.

1. Definition of sludge concentration MLSS

Activated sludge concentration refers to the content of suspended solids in the mixed solution at the outlet of the aeration tank, expressed by the symbol MLSS, and its unit is mg/L, which is used to measure the amount of activated sludge in the aeration tank. The total amount of MLSS includes the following four aspects:

active microorganisms;

Organic matter that cannot be biodegradable adsorbed on activated sludge;

Residues of microbial autoxidation;

Inorganic.

During the operation, it should be noted that MLSS only refers to the concentration of the mixed solution in the aeration tank, and does not consider the concentration of the mixed solution in the secondary sedimentation tank. At the same time, when monitoring the concentration of the mixed liquid in the aeration tank, it should be noted that the concentration of the mixed liquid at the outlet of the aeration tank is used as the standard to measure the concentration of activated sludge in the entire aeration tank.