Pretreatment of landfill leachate by chemical oxidation processes

Abstract

Kinetics and efficiency of Fenton’s and ozonation processes for the pretreatment of two landfill leachates (fresh and mature) resulting from municipal waste disposal were studied. Both samples presented high organic load, high toxicity and low biodegradability. These were the reasons why oxidative treatment was proposed. Fresh and mature leachate showed different behaviors in the oxidation experiments. The final extents of removal were attained in comparable time intervals in both oxidation systems. Maximal removal of organics by the Fenton’s oxidation reached more than 50 % according to COD. Zero or first order kinetics were found the best to describe the organic components (in terms of COD and DOC) removal by the Fenton’s oxidation for both landfill leachates. Higher reaction rate values of the Fenton’s oxidation were achieved with fresh leachate samples. The efficiency of initial organics removal with ozone was about 70 % for mature leachate, while in case of the fresh one only 41 % of COD were removed. The best fits of COD and DOC experimental data from oxidation of fresh and mature leachates were obtained by a combined kinetic model. No significant improvement of the biodegradability of landfill leachates was achieved using these treatment procedures. Regarding toxicity, ozonation showed to be more effective than the Fenton’s oxidation. Advanced oxidation experiments confirmed that the Fenton’s oxidation and ozonation are comparable oxidative treatment techniques for the reduction of organic pollution in the investigated municipal landfill leachates. However, neither of them is effective enough to be used as a pretreatment method followed by biological treatment.

Fenton and solar photo-Fenton processes for the removal of chlorpyrifos insecticide in wastewater

“…It is worth noting that several authors have reported that the decaying profile of COD obtained by Fenton oxidation of organic molecules can follow pseudo-second-order kinetics (Guedes et al, 2003;Ratanatamskul and Auesuntrachun, 2009;Argun and Karatas, 2011;Derco et al, 2010).…”

Treatment of landfill waste, leachate and landfill gas: A review

“…The two component combined model consisted of the summation of two first order models, one for easily and another for hard oxidable. The Fenton's oxidation best fit the zero and first order models and the ozone treatment best fit the combined model [94]. These kinetic models only represent the experimental conditions used in this study.…”

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“…The adsorption and Fenton intensive oxidation processes can remove both particulate and dissolved matter. The experience in organic matter removal superior to the coagulation-flocculation processes -of 50 to 70% COD removal-can be found in the literature (Wang et al, 2003;López et al, 2004;Xing et al, 2008;Abdul et al, 2009;Foul et al, 2009;Derco et al, 2010).…”