In the AO treatment process, large amounts of duckweed grow in the anoxic tank
Thread Content
Since the water supply to the plant is not very stable, the COD level of the incoming water is currently around 100 only. As a result, there is less and less sludge in the biological treatment tanks, and there’s an abundance of duckweed in the anoxic tank. I believe it’s due to an imbalance in nitrogen and phosphorus levels. However, I’m hesitant to keep discharging sludge, as its amount is already decreasing~~~ Are there any other solutions? PS: I took some measures on my own to reduce the aeration volume in the aerobic stage, and to minimize or even eliminate the return of the sludge mixture from the aerobic tank to the anoxic tank! It should work, I guess
Reducing the aeration volume is the right approach; reducing sludge discharge and lowering the recirculation rate are also necessary measures. However, care must be taken to prevent anaerobic conditions in the secondary sedimentation tank.
Intermittent operation can be considered: maintain SV at no less than 10%, use aeration to raise DO to around 1, then stop aeration for 2–3 hours; if the effluent parameters meet the requirements, this period can be extended further.
Your load is too low; intermittent aeration will suffice to control dissolved oxygen levels. The higher the dissolved oxygen in the anoxic tank, the faster water lilies will grow