<p>Natural organic matter (NOM) and particulates in freshwater resources bring about environmental and health concerns during conventional disinfection processes. The simultaneous, one-step, and deep removal of such contaminants is still an issue for water industries. Here, polyaluminum chloride (PAC) samples synthesized at the OH/Al molar ratios (basicity) of 1.6, 1.8, and 2.4 were subjected to short-term aging (7, 14, and 21 days) and employed for the coagulation of natural and synthetic runoff at very low dosages ranging 0.2-1.0 ppm. Furthermore, UV₂₅₄ (an index of NOM) and turbidity removals were investigated in light of the Al species content of the coagulants. When PACs with the basicity of 1.8 were applied to treat the natural water, the aging period profoundly impacted NOM removal, i.e., the 21-day-aged coagulant achieved 100% UV₂₅₄ elimination at a dose of 0.4 ppm, substantially outperforming that subjected to 14-day aging. Moreover, in the case of high-basicity PACs, the aging periods impacted the turbidity removals while NOM remained unchanged. For instance, an increment of turbidity removals, up to 94%, was observed by applying the coagulant with a basicity of 2.4, aged for 21 days at a dose of 0.8 ppm, corresponding to UV₂₅₄ elimination of 95%. It is supposed that monomeric and highly polymeric Al species, contributing to charge neutralization and patching, deliver a more significant impact on eliminating turbidity and NOM, respectively. Our findings bring sustainability to the several steps of water treatment, including coagulation, disinfection, and sludge disposal, through reducing chemical consumption, sludge production, and operational cost.</p> Graphical Abstract <p></p>