Temperature Effects on Flocculation Kinetics Using Fe(III) Coagulant

Abstract

The effect of low water temperature on flocculation kinetics was examined using ferric nitrate to coagulate kaolin clay in water under tightly controlled treatment conditions. Both the particle size distribution data obtained from an automatic image analysis system and the on-line measurement of the degree of turbidity fluctuation in a flowing suspension by a photometric dispersion analyzer were used to measure flocculation kinetics. Results show that cold water temperature had a pronounced detrimental effect on flocculation kinetics. To improve flocculation kinetics at low water temperature, maintaining constant pOH to adjust water chemistry for temperature changes was found to be partially effective, but only in the more acidic pH range studied (≤pH 6.8). However, the improved performance did not reach the performance at room temperature.