Leachate, a wastewater produced when rainwater percolates through landfill materials, is a global concern for environmental contamination. The goal of the current research was to treat young landfill leachate using aerobic-anaerobic, coagulation-flocculation, and advanced oxidation technologies considering the significance of the pollution caused by landfill wastewater on a global scale. High turbidity, a dark brown colour, and dissolved organic compounds were removed from a leachate that was collected in Chimbo, Ecuador. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were both lowered by anaerobic biodegradation by 60% and 67%, respectively, after 42 days. Without adjusting the pH, coagulation with polyaluminium chloride and ferric chloride effectively removed suspended particles. By using 4 g/L of activated carbon and 4000 ppm of H2O2 , the advanced oxidation process (AOP) reduced COD by 95%, BOD by 96%, and dark brown colour by 89%. Activated carbon as catalyst and H2O2 as oxidant is a potential approach for high colour removal at a moderate cost.