A mathematical model to predict the performance of the secondary clarifier of a municipal wastewater treatment plants

The activated sludge process for urban wastewater treatment has a high purification performance and reliability, especially for organic pollution. However, it presents several operational insufficiencies, such as sludge control, pollution degradation monitoring, and liquid/solid separation problems in the biological reactor/secondary clarifier couple. This paper presents an analysis of a secondary clarifier of wastewater treatment plant (WWTP) via an activated sludge, which could be used for the plant optimization. The models of the settling velocity and the secondary clarifier based on the sludge volume index (SVI) are addressed. We have proposed these models to explain the settling velocity activities and illustrate the relationship between the settleability characteristics. This research aims to develop and predict a one-dimensional model (1-D model) based on an exhaustive experimental study performed on the WWTP and online information, which are the total suspended solids (TSS), the SVI, and the influent characteristics. The results of the novel model for the secondary clarifiers integrating the empirical settling velocity equation presented a good agreement and a better fit with our experimental results, with an error of approximately zero. This simulation is a perfect complement to the management solution and the hydraulic overload monitoring of WWTPs.