Immediately after adding the coagulant, water was mixed at approximately 800 rpm for one minute using a magnetic stirplate (n.b., rpm is nominal and was determined by the stirplate dial setting). Coagulated water was then mixed for 12.5 minutes each at 600, 500, and 400 rpm. pH was maintained throughout at 6.3 using sodium hydroxide. The flocculated water was allowed to settle overnight, pumped into a separate reservoir, and filtered using a vacuum flask fitted with a 1.5 µm glass-fibre filter membrane. This procedure reduced total organic carbon (TOC) to 1.8 mg L -1 (standard deviation 0.02 mg L -1 ), from an approximate raw water concentration of 3.8 mg L -1 (a summary of untreated water quality is provided in Table ). TOC samples were collected, headspace-free, in 40 mL clear glass vials and preserved with concentrated phosphoric acid to pH < 2. Vials were washed and then baked at 105°C for at least 24 h before use, and TOC was quantified using a Shimadzu TOC-V CPH analyzer. Filtrate was dosed as needed with H3PO4, Al2(SO4)3 • 18H2O, and NaHCO3 (5 mg C L -1 ) to achieve the experimental conditions listed in Table . The initial pH for all test waters was adjusted to 7.5 with HNO3 and NaOH. pH was measured using a combination electrode, and the nominal orthophosphate concentration was verified colorimetrically. 24