How to solve the problem when the content of suspended solids increases in the secondary sedimentation tank?

Phenomenon 1: Activated sludge bulking deteriorates sludge settling performance, the mud-water interface is close to the water surface, and part of sludge debris overflows through the effluent weir.

Countermeasure 1: Analyze the causes of sludge bulking and eliminate them one by one.

Phenomenon 2: The sudden increase of water inflow increases the hydraulic load on the surface of the secondary sedimentation tank, which leads to the increase of the upflow velocity and affects the normal settlement of activated sludge, and the sludge debris enjoined by the water flow overflow through the effluent weir.

Countermeasure 2: Give full play to the role of the regulating pool, so that the water intake as balanced as possible.

Phenomenon 3: The concentration of activated sludge in the aeration tank is high, the mud-water interface of the secondary sedimentation tank is close to the water surface, and part of the sludge debris overflows through the effluent weir. 

Countermeasure 3: increase the residual sludge discharge.

Phenomenon 4: The flocculation of sludge decreases or disappears due to the disintegration of activated sludge, and the sludge debris flows out with the water. 

Countermeasure 4: Find out the reason of sludge disassembly, eliminate and solve one by one.

Phenomenon 5: The working condition of the mud suction (scraping) machine is not good, resulting in the phenomenon of short flow of sludge or water flow in the secondary sedimentation tank. Some sludge cannot return in time, and some sludge stays in the secondary sedimentation tank for too long.

Countermeasure 5: Timely repair suction (scraping) mud machine, make it return to normal working state.

Phenomenon 6: The residence time of activated sludge in the secondary sedimentation tank is too long, and the sludge overflows with the water flow after being decomposed due to hypoxia.

Countermeasure 6: Increase the amount of returned sludge and shorten the residence time in the secondary sedimentation tank.

Phenomenon 7: When the water temperature is high and the nitrate content in the water is high, denitrification and denitrification of sludge occur in the secondary sedimentation tank, and large sludge coated with nitrogen rises to the surface and then spills over with the water flow.

Countermeasure 7: Increase the amount of returned sludge and shorten the residence time of sludge in the secondary sedimentation tank.