Eco-Friendly Optimization of Landfill Leachate Treatment via Agricultural Waste-Derived Coagulants and Advanced Oxidation

Abstract

Landfill Leachate (LL) presents a significant environmental concern, particularly in rapidly developing nations such as Oman, due to its high concentrations of persistent pollutants including ammonia (NH3), color-causing compounds, and organic matter. These contaminants are often resistant to removal by conventional treatment methods. This study aimed to develop an effective and eco-friendly treatment strategy for stabilized LL by integrating two processes: Persulfate Advanced Oxidation Processes (P-AOP) and Coagulation-Flocculation (C-F). The specific objectives were to: i) extract natural coagulants from date pits using the Soxhlet method, ii) enhance pollutant removal through the combined P-AOP and C–F approach, and iii) optimize the process using Response Surface Methodology (RSM). The hybrid treatment method achieved high removal efficiencies: 96% for color, 60% for NH3, and 74% for Chemical Oxygen Demand (COD). Additionally, a 12.433×103% increase in Total Suspended Solids (TSS) was observed, attributed to floc formation, which signifies effective coagulation. These findings confirm the potential of the integrated approach and highlight the feasibility of using date pits as a sustainable alternative to chemical coagulants.