What to do about rapid growth of sludge in aquaculture wastewater?
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For aquaculture wastewater, there is an UASB anaerobic reactor at the initial stage and an aeration tank at the subsequent stage. Currently, the COD level of the anaerobic treated water is 12,000 mg/L, while that of the aerobic treated water is 660 mg/L. The sludge in the aeration tank is accumulating rapidly; 20–30 m3 of wastewater is introduced daily, resulting in fast sludge growth. What should be done?
At N. P. Water temperature. DO. PH. Under appropriate conditions, the growth rate of sludge is proportional to the organic load in the influent; a higher DOB in the influent results in a faster sludge growth rate (here MLSS is referred to rather than SV30, as factors such as sedimentation properties and sludge bulking affect SV30). Ways to reduce sludge: 1. Extend the sludge retention time, putting the activated sludge process into the endogenous respiration phase ； 2. Increase DO and deepen the reaction process, relying on the oxidation within the activated sludge tank itself to reduce sludge ； 3. Reduce water inflow or organic load ； 4. Increase sludge discharge ； 5. Reduce the return flow rate from the secondary sedimentation tank.