Optimization of stabilized anaerobic landfill leachate treatment using ozonation with metallic compound using...

Malaysia encounters a consistent rise in the generation of solid waste and leachate on a daily basis. It should also be noted that leachate has a low degree of biodegradability (BOD₅ /chemical oxygen demand [COD]), as shown by its BOD₅ /COD ratio. Its high toxicity levels significantly threaten the environment, water bodies, and human well-being. High concentrations of COD, color, and ammoniacal nitrogen (NH₃ -N) in leachate prevent this wastewater from being allowed to be discharged directly into the water body. Therefore, an effective process to remove the pollutant is desired. The aims of this study are to investigate the performance of ozonation with two metallic compounds, ZrCl₄ and SnCl₄ , and optimize their performance using response surface methodology (RSM). In this study, the performance of ozonation with ZrCl₄ (O₃ /ZrCl₄ ) recorded better pollutant removals compared with the ozonation with tin tetrachloride (O₃ /SnCl₄ ), as seen in the removals of 99.8%, 93.5%, and 46.3% for color, COD, and NH₃ -N, respectively. These removals were achieved by following the experimental model (optimum experiment condition) generated by RSM at O₃ dosage of 31 g/m³ , COD and ZrCl₄ dosage ratio (COD, mg/L/ZrCl₄ , mg/L) of 1:1.35, with the pH solution of 8.78 and reaction time of 89 min. The R² of each parameter for this model was recorded as 0.999 (COD), 0.999 (color), and 0.998 (NH₃ -N), respectively. These data indicated that the model is well fitted as the predicted data by statistical calculation and in good agreement with the actual data. PRACTITIONER POINTS: The performance of O₃ /ZrCl₄ and O₃ /SnCl₄ was examined for remediate stabilized landfill leachate. The performance of O₃ /ZrCl₄ and O₃ /SnCl₄ was optimized using RSM, and a set of experimental models was generated and tested. O₃ /ZrCl₄ recorded the higher removal of COD, color, and NH₃ -N compared with O₃ /SnCl₄ . At best condition, both methods recorded removal as 89% to 99.8% of pollutants in leachate and product clear effluent. This finding gives a new approach to treat landfill leachate effectively and efficiently.