Coagulation is a process of destabilizing colloidal charges with a substance called coagulant. This research studies the coagulation of synthetic sludge water samples using commercial Al2SO4 (alum) coagulant. Coagulation was carried out using the jar test method and magnetic stirrer with variations in speed of 20, 30, 40, 50 rpm and time of 8, 10, 12, 14 minutes. Water quality parameters observ…