Development of Screening Methods for Secondary Settling Tanks Monitoring and Optimization

Abstract

Lately, the environmental awareness that leads to legislation changes has been pushing the waste water treatment plant (WWTP) operators to increase the secondary settling tanks’ (SST) efficiency in order to meet the new requirements. The SST efficiency is commonly understood as the ability to separate suspended solids from the effluent water. The internal SST dynamics depends strongly on both physical and biochemical properties of the activated sludge and thus the sludge properties are specific for every tank. Also, the geometry of the influent and effluent objects determine the sludge behaviour and are therefore often a subject to research and modification through the use of numerical models. The aim of this paper is to describe an innovative screening method that enables for better capturing of the current state SST sludge behaviour and with the cooperation of the numerical model provides a tool for SST geometry optimization. The benefit of this method compared to traditionally used models lays in utilizing both the experimental measuring data and numerical model data together to provide for a good calibrated model that can be used for efficient SST optimization.