New activated sludge theory: steady state

This theory emphasizes diffusion resistance to mass transfer in the floc particles and biopolymer production from recycled bacterial protoplasm. The diffusive effectiveness factor is a simple function of sludge age and hydraulic residence time. The diameters and settling velocities of the floc particles are predicted. Specific bacterial respiration rate, specific soluble substrate as‐similation rate, and floc settling velocity data from the literature are correlated by the theory.