The use of zeta potential measurement as a control tool of surface water coagulation

The implementation or optimization of the coagulation process requires prior preliminary tests. Standard Jar-Test method is time-consuming, inaccurate and may not work well, especially for the waters characterized by high variability of quality parameters. Zeta Potential Isoelectric Point (IEP) analysis may give fast and precise data on the coagulant type and dose required for maintaining an efficient coagulation process. The research objects included the surface waters taken directly from the Mala Panew and Odra rivers. The zeta potential and set coagulant dose dependence was measured for each sample. Four aluminum-based coagulants with different characteristics were used in this research: aluminum sulfate (Alum), polyaluminum chloride (PAC), dialuminum chloride pantahydroxide (PACl), polyaluminum chloride hydroxide sulfate (PACS). Charge neutralization effectiveness, by means of Zeta Potential IEP analysis, was the basis for the choice of the most effective coagulant doses. The coagulation process efficacy was based on the parameters of the treated water (pH, turbidity, color, alkalinity), reduction of organic matter (Abs254, Total Organic Carbon (TOC), Dissolved Organic Carbon (DOC) and residual aluminum contamination. The Zeta Potential utility evaluation was based on the DOC reduction.