AWWA JAW57435

Inorganic polymer flocculants (IPFs) are used as water and wastewater treatment reagents. These preproduced IPFs can be considered the second generation of the metal salt coagulants. It has become evident that differences occur in coagulation between polyaluminum chloride (PACl) and polyiron chloride (PICl), related to basicity (B). The formation and stability of polymers cause significant different behavior using PACl and PICl during the coagulation process. A high B value can be favorable for PACl preparation, but it is not fit for PICl. Therefore, a scientific design and application are needed for IPFs according to primary water quality conditions. The authors sought to answer two questions. First, is there any difference between coagulation with Al(III) and Fe(III) and their hydrolysis products as a result? Second, can iron-based IPFs be equal in efficiency with aluminum-based IPFs? This article addresses the reasons for the differences in coagulation and suggests that a different parameter (B value) should be adopted to prepare PICl in comparison with PACl. Includes 26 references, tables, figures.