Influence of COD on phosphorus removal granular sludge stability
COD对生物除磷颗粒污泥稳定性影响研究

The stability was one of important factors for application of granular sludge. With the influent COD concentration changed the stability of the biological phosphorous removal granular sludge was studied in a sequencing batch reactor (SBR). When the influent COD concentration gradually increased from 300 mg/L to 500 mg/L, the phosphorus removal efficiency decreased from 93% to 88%. When the influent COD concentration was below 400 mg/L, the max. specific phosphorus release rate and the max. specific phosphorus uptake rate were 45.2 mg/(g MLSS·h) and 33.5 mg/(g MLSS·h), respectively, and the phosphorus content of MLSS was 5.6%~7%, and the effluent SS was below 50 mg/L. When the influent COD concentration was stepped up to 550mg/L, the phosphorus removal efficiency decreased to 63%, the effluent SS was above 150 mg/L, the filamentous bacteria overgrew, and the granular sludge was disintegrated. The biological phosphorous removal granular sludge could stand some impacts of COD concentration, and the system would break down at high COD concentrations.