A comparative study of UV–Fenton, UV–H2O2 and Fenton reaction treatment of landfill leachate

Abstract

In this study, laboratory experiments were conducted to compare the efficacy of several H2O2‐based advanced oxidation processes (AOPs): UV–Fenton, UV–H2O2, and Fenton reagent, to treat landfill leachate with the objective of removing COD and improving the leachate’s overall biodegradability (evaluated in terms of BOD5/COD ratio). The results indicated that, at optimized experimental conditions of 25 °C, pH 4.0, 4000 mg L−1 H2O2, 30 mg L−1 Fe(II) (for UV–Fenton and Fenton ) and 60 min reaction time, the UV–Fenton system showed the highest COD removal. The COD removal rate in the H2O2‐based AOPs was strongly dependent on the concentration of H2O2 and the pH value. Temperature had little effect on overall COD removal rate in the Fenton and Fenton‐like systems. All three systems would result in a significant increase in the ratio of BOD5/COD, from 0.17 to about 0.60, at the applied H2O2 dosage of 4000 mg L−1. The increase in biodegradability of the AOP leachate indicates that these AOPs would be beneficial for the subsequent biological treatment process. The UV–Fenton process was found to be the most effective approach of these H2O2‐based AOPs to enhance the biodegradability and eliminate the colour of the leachate.