Investigation of Coagulation mechanisms with Fe(III) Salt Using Jar Tests and Flocculation Dynamics

Kim, Jeongsook; Kang, Limseok

Environmental Engineering Research 1998;3(1): 11-19.

Jeongsook Kim¹^†, and Limseok Kang²

¹Engineering Research Center, Pukyong University
²Department of Environmental Engineering, Pukyong National University

Corresponding Author: Jeongsook Kim ,

Received: April 6, 1997; Accepted: January 7, 1998.

ABSTRACT

This research focuses on the use of ferric nitrate as a coagulant to study coagulation mechanisms of orthokinetic flocculation. The mechanisms of flocculation were studied for systems of kaolin suspensions using a conventional jar test and an 18 / batch reactor test under tightly controlled treatment conditions. The measurement of flocculation dynamics was done by assessing the rate of changes in total particle number concentration and used as a tool to investigate flocculation mechanisms. Clear differences in coagulation mechanism were noted from the result of jar tests and flocculation dynamics tests. Especially, the flocculation dynamics tests by means of measuring particle size distribution provided reliable and sensitive indications of coagulation mechanisms. The flocculation dynamics under sweep floe conditions was much faster than the dynamics under adsorption/destabilization conditions. Complete charge neutralization was not good enough to bring about faster rate of flocculation.

Keywords: Ferric nitrate | Coagulation mechanisms | Coagulation dynamics | Jar test | Particle number