Laundry waste is commercial waste that has a negative impact on the environment. This waste can be treated by using  coagulant to reduce its turbidity, phosphate levels, and anionic surfactant levels. In this study, the waste treatment was carried out through a coagulation-flocculation process using chitosan and alum as coagulants. The optimum dosage and pH of chitosan and alum coagulants were studied to determine the effectiveness of coagulants in laundry waste treatment. The results showed that the optimum dose for chitosan was 10 mg/L and alum was 80 mg/L. The decrease in turbidity, phosphate content, and anionic surfactant content for chitosan coagulant were 92.02%, 87.04%, 78.39%, and alum coagulant by 91.67%, 86.34%, 77.34% respectively. A pH value of 6 is the optimum pH value of coagulation for both chitosan and alum to treat laundry waste. The decrease in turbidity, phosphate levels, and anionic surfactant levels for chitosan coagulants was 92.65%, 85.95%, 82.91%, while the use of alum coagulant gave a decrease of those parameters by 91.49%, 84.97%, 80.19%, respectively.

Keywords: Laundry waste, coagulant, effectiveness, coagulation-flocculation