Kinetics of biological phosphorus behavior in sequential batch reactor under anaerobic/aerobic condition

A kinetics study of biological phosphorus release/uptake in biomass under anaerobic/aerobic (A/O) condition was made in a laboratory sequential batch reactor (SBR) system. The ratios of P/BOD and TN/BOD of influent feed solution for increasing the intracellular phosphorus must be greater than about 0.01 and 0.13 in this system. Phosphorus uptake was correlated to the uptake of K+ and Mg2+ as K/P = 0.28, Mg/P = 0.36 by molar ratios. The rate of phosphorus release for endogeneous respiration of the biomass under anaerobic condition can be described by using A Monod-type equation with respect to phosphorus content in the biomass, and the values of the rate constant, Krp, and the saturation constant, Kkp, are 1.1 × 10-3 h-1 and 1.4 × 10-3 kg/kg respectively. The rate of luxurious phosphorus uptake at the aerobic stage can be expressed by a first-order kinetic equation based on Pxm-Px with the rate constant, Ku, is 0.017 h-1.