A Scale-up Design Procedure for Rotating Biological Contactors

Abstract

A scale-up design procedure, based on a new physical mass transfer (PMT) model, whichdescribes the performance, for aerobic rotating biological contactors (RBC’s) is developed. This scale-up procedure can be used to determine the disc surface area needed to prevent an oxygen limitation or to obtain a specific degree of treatment. In contrast to the empirical, and most previous RBC performance model, a major advantage of the PMT model in design is that it can predict the onset of oxygen limiting conditions since it accounts for the fact that low dissolved oxygen concentrations can limit the growth rate of the attached microorganisms. The PMT model can be used to predict the oxygen limiting loading rate so that this loading rate is not exceeded in practice. The proposed procedure has been successfully applied to design and install two relatively small full-scale domestic RBC units in parallel treating a cement plant wastewater efficiently.