Improvement of sludge uneven distribution in three ditch oxidation ditch

① the difference of sludge concentration in three ditch oxidation ditch is caused by the operation mode of three ditch oxidation ditch and the time distribution of each operation stage. Increasing the time of denitrification stage can greatly reduce the difference of sludge concentration.

(2) the difference of sludge concentration in the side ditch is due to the energy carried by the water from the middle ditch, which is easy to cause the instability of the outlet water and the uneven load of the oxidation ditch. This problem can be solved by installing a guide grid.

③ the operation mode of the side ditch of the three ditch oxidation ditch is sequential, similar to the SBR process, the sludge concentration changes with the operation state, and the difference between the sludge concentration of the middle ditch and that of the three ditch oxidation ditch is large, which should be fully considered in the process design.