The Performance of Iron Nanocomposites as Persulfate Activators in Permeable Reactive Barrier Technology for Treatment of Landfill Leachate

Abstract

Landfill leachate contains a large organic load and a wide spectrum of pollutants, and it needs appropriate treatment to reduce the severity of these contaminants. Therefore, the present study aimed to remove chemical oxygen demand (COD) and ammonia (NH₃ ) as target contaminants from the landfill leachate. To this end, the zero-valent iron nanofibers/reduced ultra-large graphene oxide (ZVINFs/rULGO) and converter sludge (CS) were used as persulfate (PS) activators in permeable reactive barrier (PRB) technology for removing COD and NH₃ . The Box–Behnken design (BBD) was employed to determine the possibility of using each activator and optimize three parameters: activator, pore volume (PV), and flow (mL/min) using target contaminants. In the Batch process, the effects of pH, activator concentration, and PS/COD mass ratio on COD removal were examined. The BBD experiments provided a satisfactory predictive model, indicating that ZVINFs/rULGO is superior to CS when used as activators of PS in PRB technology. The biochemical oxygen demand (BOD₅ )/COD ratio increased from 0.24 in raw leachate to 0.67 in treated leachate, and leachate toxicity was reduced by more than 85%. Additionally, the ZVINFs/rULGO and CS contributed to the activation of PS.

Keywords: Landfill leachate, COD, NH3, Persulfate, Activators,