Water Treatment > Quality Water Solutions > Coagulation Control > Zeta Potential

Zeta potential defines the charge on particles and colloids in water by measuring how fast particles move across a microscopic grid toward an anode or cathode. Various water parameters, machine constants and water temperature are factored into the value. Today's Zeta potential measuring devices use advanced microprocessors. Some have TV screens that show particle movement while the system tracks, times and calculates.

Zeta potential indicates the degree of neutralization, so it measures how well a coagulant is working and signals the need to alter dosage as water conditions shift. Anticipated or proposed dosage changes can be quickly assessed from the Zeta potential of floc in jar tests that simulate the initial mixing chamber. Some units contain flowthrough cells so dosage can be changed as a raw water sample is measured, which saves time and effort. Even though Zeta potential is not an on-line method and cannot signal metering pumps to alter delivery rate, it opens an important window into the coagulation microenvironment.

The use of a microscope in this evaluation also allows operators to record the type and amount of algae present. Since many algae affect coagulant performance as well as taste and odor, this test can fill two functions, although it is not a substitute for proper microscopic evaluation of algae.