Dynamic modeling of clarifier-thickeners for the control of wastewater treatment plants: a critical analysis

Sedimentation is central activated sludge process, and its performance has a major impact on that of the whole wastewater treatment process. Nevertheless, there is still no satisfying model for secondary settling tanks. This paper explores the reasons why the existing one dimensional models are not relevant, from the lack of knowledge on the physical phenomena to the difficulties to solve the partial differential equations. Finally, the most important modeling challenges are presented, highlighting scientific advances that have to be done.