Effect of Al speciation on residual turbidity and Al minimization by coagulation with single and dual dosing

Characterization of particles and their relation with residual aluminum in water treated with pulsating floc blanket clarifiers and conventional clariflocculators using PACl

“…The turbidity remaining in the clarified water by PFBC was 0.42 NTU on an average with standard deviation (σ) of +0.4, whereas for CC, an average residual turbidity of 1.61 NTU (σ ¼ +0.3) was observed. The results indicate that the fluidized zone of high solids concentration provided by the contracting and expanding blanket of flocs in a PFBC improved destabilization of colloidal particles, perhaps by contact flocculation (Hendricks 2006) and charge-neutralization (Chen et al 2016;Lin & Ika 2019b). As the freshly formed microflocs sift upwards through the floc blanket, constituted primarily of well-grown large flocs, collisions between these disparately sized particles occur, resulting in adsorption like flocculation caused by entrapment due to bridging and charge-neutralization mechanisms.…”

“…The behavior of these forms is affected differently by factors like pH and consequently performance parameters like turbidity removal efficiency, floc properties, and particulate and dissolved fractions of residual aluminum also vary. Hence, much contemporary research is focused towards tweaking the basicity, speciation and other properties of PACls for performance improvement (Kimura et al 2013;Shu-xuana et al 2014;Lin & Ika 2019a, 2019bSolanki et al 2020). However, the physico-chemical significance of the role the reaction environment provided by a reactor may play on the efficiency of a given coagulant like PACl for the provided control set of influent conditions has not been studied in much detail, and therefore the same constitutes the core subject matter of this paper.…”