Environmental protection method of COD degradation in wastewater treatment

Why is the removal rate of COD low in aerobic tank?

The low COD removal rate of aerobic tank in sewage treatment is related to temperature, pH, dissolved oxygen and salinity. The reasons are analyzed as follows:

① Aerobic tank sludge aging, mud age is long.

② Aerobic tank sludge load is high, sludge age is short, return flow is large, residence time is short.

③ Low load of aerobic tank sludge, high dissolved oxygen for a long time leads to sludge oxidation (low removal rate, high dissolved oxygen), more fine sludge, less active sludge.

④ Insufficient dissolved oxygen in aerobic pool.

⑤ Insufficient nutrients or unbalanced proportion of nutrients (too high proportion of N and P).

⑥ Anaerobic tank COD removal rate is low, anaerobic hydrolysis effect is poor, effluent COD concentration is too high.

⑦ Raw water contains toxic substances, sludge poisoning.

⑧ Inorganic salt accumulation value exceeds the prescribed range.

⑨ Large impact load of aerobic tank or sludge bulking phenomenon in aerobic tank.