Effects of Cationic Polyelectrolytes on the Removal of Suspended Particulates During Direct Filtration

Abstract

This research investigated the important parameters influencing the degree of particulate removal from low turbidity water in a configuration that included rapid mixing followed by filtration. The varied parameters were rapid‐mixing velocity gradient, cationic polyelectrolyte type, and polyelectrolyte dosage. The cationic polyelectrolytes were characterized for molecular weight by membrane osmometry, light scattering, and high performance liquid chromatography. The filtration kinetics variables, including maximum depth‐averaged singlecollector efficiency and specific deposit, were used to characterize the efficiency of particulate removal for each of 72 filter runs. Statistical analyses demonstrated that the choice of polyelectrolyte was the only significant factor. Additionally, volume size distribution analyses of particle count data from in‐depth samples in the filter demonstrated that the polyelectrolyte configuration may be critical for adsorption of polyelectrolytes to particulates and media in filtration.