Effects of Macromolecular Conformation upon Solid-Liquid Separation and Water Treatment Plant Residuals

Abstract

The efficiency of solid-liquid separation in coagulation -sedimentation processes depends greatly upon the performance of the coagulant with respect to the production of suitable floc properties. When high-molecular weight polymers (that function primarily by bridging between proximate primary particles) are used as coagulant-aids, the dynamic processes of polymer adsorption and macromolecular rearrangement figure prominently in the success of floc formation. Ideally, one would like to have the macromolecule adsorb quickly upon the primary particle surface in an extended, rod-like conformation; this configuration should persist throughout the collisional process to produce rapid floc growth. A period of macromolecular relaxation would then ensue, with the formation of additional affiliations between functional groups and surface sites. Recently, there have been speculations that the relative speeds of these processes may not necessarily conform to the common perception that sorption is quick and that the ...