Study On Kinetics Of Organic Degradation In Sequencing Batch Reactor (SBR)

The activated sludge coming from membrane bioreactor (MBR) was cultured and acclimated to fit sequencing batch reactor (SBR) process for the study of organic degradation kinetics. At first, glucose was used as carbon source needed in the sludge culture and acclimation. Sequentially, both glucose and phenol was used, and the ratio of phenol to glucose increased gradually until the glucose content was zero in the system. The organic degradation kinetics in SBR was studied with the acclimated activated sludge.In the kinetics experiment, chemical oxygen demand (COD) concentrations of glucose and phenol at different reaction time at about 298K were measured. These data were reduced according to the kinetics model: - d S / d t = k_SS~n Reaction order (n) and reaction rate constant (kS) were determined. When start COD concentration of glucose and phenol were below 300mg/L, the glucose and phenol degradation was all zero order reaction, and the relationship between concentration and time was linear. When start COD concentration of glucose reached 900mg/L, the glucose degradation was 0.4 order reaction. In addition, increasing flow rate (from 50L/h to 70 L/h) was proved to accelerate the reaction rate. When glucose and phenol degraded together, the glucose effect was found to cause the glucose degradation rate to increase, but the phenol degradation to decrease.During the organic degradation, the change trend of total COD in the system was observed through measuring total COD at different time, and compared with that of glucose and phenol'COD. Meanwhile, variation rules of DO with reaction time were analyzed on the basis of the measured DO data.