ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Pretreatment of landfill leachate by chemical oxidation processes

Ján Derco, Andreja Žgajnar Gotvajn, Jana Zagorc-Končan, Beáta Almásiová, and Angelika Kassai

Institute of Chemical and Environmental Engineering, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovak Republic

E-mail: jan.derco@stuba.sk

Received: 30 June 2009  Revised: 16 November 2009  Accepted: 23 November 2009

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.

Keywords: biodegradability - Fenton’s reaction - kinetics - landfill leachate - ozonation - toxicity

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-009-0116-5

Chemical Papers 64 (2) 237–245 (2010)