The Importance of Zeta Potential in Water Treatment Process Control

Control of the flocculation process and adjustment of coagulant dose during the course of water and waste water treatment is often a challenging step in the water treatment process. Zeta potential is a measure of the electrical potential between particles, and indicates the repulsive interaction between particles; a zero zeta potential means that the conditions for aggregation of contaminants are maximized. Monitoring zeta potential during the water treatment process allows for accurate and precise assessment of the charge neutralization process required for optimal coagulation of contaminants.

The benefits of using zeta potential measurement to determine water treatment-control strategies have been documented through case studies and will be reviewed. Results from both laboratory analyzers (Zetasizer Nano Z) and the on-line, automatic system (Zetasizer Lab Blue) will be discussed. Based on plant processing requirements, on-line real time monitoring is often preferred for water treatment optimization. On-line continuous process zeta potential monitoring benefits will be illustrated, by reporting on the experiences of a newly built hybrid facility, Tacoma Water, a utility in WA and Aurora Water a utility for Aurora Colorado as well as other water treatment facilities in the US and UK.