Effect of Modified Micro-Sand, Poly-Aluminium Chloride and Cationic Polymer on Coagulation-Flocculation Process of Landfill Leachate

Sanitary landfill leachate is considered as highly polluted wastewater, if without any treatment and discharge into water system will affect water quality. This study was carried out to assess the treatability of the semi-aerobic landfill leachate via coagulation-flocculation using poly-aluminum chloride (PAC), cationic polymer and modified micro sand. Leachate was collected from Pulau Burung Sanitary Landfill located in Penang, Malaysia. Coagulation-flocculation was performed by using jar test equipment and the effect of pH, dose of coagulant and polymer toward removal of chemical oxygen demand (COD), color and suspended solid (SS) were examined. Micro sand also had been used in this study to compare settling time between coagulation-flocculation process with and without the aid of micro sand. The optimum pH, dose of coagulant (PAC) and dose of polymer (cationic) were achieved at 7.0, 1,000 mg/L and 8 mg/L, respectively. The dose of micro sand used for the settling time process is 300 mg/L. Results showed 52.66 % removal of COD, 97.16% removal of SS and 96.44% removal of color were obtained under optimum condition. The durations of settling time to settle down the sludge or particle that formed during coagulation-flocculation process were recorded at 1 minute (modified sand), 20 minutes (raw micro sand) and 45 minutes (without micro sand).