Efficient Fenton/biological activated carbon filter process for treating landfill leachate

Abstract

Landfill leachate is recognized as one of the most difficult organic wastewaters to treat. This study, which aims to address the challenge of treating landfill leachate, developed a new combined process of Fenton/biological activated carbon filter, achieving efficient treatment of organic matter and ammonia nitrogen (NH 3 -N). Fenton oxidation method results showed that under optimal conditions (pH 4, H 2 O 2 dosage 15 mL/L, n(H 2 O 2 ): n(Fe 2 + ) ratio of 4:1, and a reaction time of 100 min), removal efficiencies for COD, chromaticity, NH 3 -N reached 75.05%, 98.32%, 30%.Response surface method was employed to investigate the Fenton oxidation method, and the significance levels of its influencing factors were determined to be pH value >H 2 O 2 dosage>n (H 2 O 2 ): n (Fe 2+ )>reaction time. Optimal test conditions, along with 74.36% COD removal as confirmed by experimental verification, indicating minimal error. In the SPC/Fe²⁺ method, optimal conditions were pH 4, SPC dosage 5.1 mL, n (H 2 O 2 ): n (Fe 2+ ) 4:1, and reaction time 100 min.Removal efficiencies of COD, chromaticity, NH 3 -N were 58.39%, 84.21%, 20.30%. Biological activated carbon filter was relatively effective in COD removal, reaching 27.3%, and was very effective in treating NH 3 -N:61.90%. The Fenton/biological activated carbon filter combination process exhibits a significant degradation effect on landfill leachate, with COD, NH 3 -N, chromaticity removal efficiencies of 81.86%, 73.33%, 98.50%. Landfill leachate biodegradability increased from 0.31 to 0.51, indicating the mechanism by which the biological activated carbon filter removes organic matter and NH 3 -N. It is a new process with promising research directions, both theoretically and practically significant, for achieving efficient leachate treatment.