(1) Water pH: If PAC is added and hydrolyzed to produce AI(OH)3 colloid, the dissolution is minimal when the pH is between 6.5 and 7.5, and the coagulation effect is also good;
(2) Water alkalinity: When the alkalinity is insufficient, the coagulant will continuously produce H+ during the hydrolysis process, causing the pH value to drop and the coagulation effect to decrease;
(3) Water temperature: When the temperature is low, the viscosity of water is high, the hydrolysis rate is slow, the flocs are formed slowly, and the structure is loose, the particles are small and not easy to precipitate;
(4) Composition of impurities in water: The nature and concentration have a great influence on the coagulation effect.
