Performance improvement and mechanism of composite PAC/PDMDAAC coagulant via enhanced coagulation coupled with rapid sand filtration in the treatment of micro-polluted surface water

Coagulation efficiency and removal mechanism for composite coagulant polyaluminium chloride/polydimethyldiallylammonium chloride in treating lightly micro-polluted raw water of Yangtze River in autumn

“…The zeta potential values of the resulting supernatants give an indication of coagulants having positive charges which enable them to remove negatively charged suspended particles in raw surface water, predominantly by charge neutralization, depending on the coagulant dosage used. Generally, the negative potential of the residual particles in the supernatant water after using the composite coagulant is lower than when using PAC only without regard to supernatant turbidity, suggesting enhanced charge neutralization within the dosage range used (López-Maldonado et al, 2014;Olukowi et al, 2022). The destabilization of colloid particles during coagulation, and their ability to agglomerate and form flocs, can be monitored by zeta potential values -particles with a less negative value after treatment have a smaller repulsive force and can easily settle (Wei et al, 2009;Adebayo et al, 2021).…”

“…Polydimethyldiallylammonium chloride (PDMDAAC) is a watersoluble cationic polymer with unique functional groups enabling interactions favouring coagulation, and is approved for drinking water treatment (Edzwald, 2011). When compared with other linear polymers, it has a high positive charge density with the advantage of good water solubility, easy control of molecular weight (MW) measured as intrinsic viscosity, enhanced removal efficiency at reduced dosage, and is non-toxic (Bolto et al, 1999;Zhang et al, 2009;Zhang et al, 2010;Li et al, 2015;Olukowi et al, 2022). Haarhoff and Cleasby (1989) found that PDMDAAC had a good removal effect for algal extracellular organic matter (EOM) and algal cells during the treatment of algae-polluted raw water.…”

“…However, these studies were carried out under the requirement of limiting the residual turbidity of the supernatant water to between 2.0 and 4.0 NTU (Yang et al, 2012;Adebayo et al, 2021). Furthermore, some literature reviews have found that the composite inorganic salt/PDMDAAC coagulant can enhance the charge neutralization, polymer-bridging, and net capturing of suspended colloidal particles in the treatment of lightly micropolluted surface raw water, which strengthens the flocculation/ precipitation and adsorption processes resulting in improved water quality parameters (Wei et al, 2009;Bolto et al, 1999;Shen et al, 2017;Olukowi et al, 2022). This enhanced the overall removal efficiency for colloidal particles and other water quality indicators (Yilun, 2019;Adebayo et al, 2021).…”

The Community's Dynamics Towards Clean Water Adequacy and Membrane Technology in Bojonegoro, Indonesia

“…Many strategies and technology must be developed to improve clean water quality and fulfill their needs. In some regencies, the strategy used filtration to separate chemical impurities and various pathogens (Ilyas et al, 2021;Olukowi et al, 2022;Pandey et al, 2014). This strategy is used because there is less groundwater and springs, so that the majority of water use today is surface water.…”