Use of monod kinetics on multi-stage bioreactors

Abstract

At present, the alternatives of constructing either large units in biological waste water treatment plants (in this case single-stage activated sludge basins) or a few smaller units—either multi-stage reactors or reactors connected in series, is gaining more and more importance. In West Germany, in a recent workshop dedicated to this subject, it became evident that the knowledge of the significance of volume and/or sludge loads gained in decades of operating single-stage activated sludge tanks cannot readily be applied to multi-stage units. By extending the Monod reaction kinetics model for enzyme-substrate reactions a process analysis is carried out for a series-connection of up to four CSTR (completely stirred reactors) and the author presents a few graphical solutions to characterize and design a cascade-connected system.