Mohd Zin, Nur Shaylinda, et al. “Coagulation-Flocculation of Leachate by Using Single Coagulant Made from Chemical Coagulant (Polyaluminium Chloride) and Natural Coagulant (Tapioca Flour)”. International Journal of Integrated Engineering, vol. 11, no. 6, Sept. 2019, pp. 236-43, https://penerbit.uthm.edu.my/ojs/index.php/ijie/article/view/4942.