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This article has been retracted as it is essentially identical in title and technical content with a previously published paper “Mahvi AH, Roodbari AA, Nabizadeh Nodehi R, Nasseri S, and Dehghani MH, et al. (2012), Improvement of landfill leachate biodegradability with ultrasonic process. PLoS ONE 7(7): e27571.doi:10.1371/journal.pone.0027571,” and it was found of significant similarity with the published article “A. Roodbari, R. Nabizadeh Nodehi, A. H. Mahvi, S. Nasseri, M. H. Dehghani, and M. Alimohammadi, Use of a sonocatalytic process to improve the biodegradability of landfill leachate,” Braz. J. Chem. Eng. vol. 29 no. 2 São Paulo Apr./June 2012,

E-Journal of Chemistry
Volume 9 (2012), Issue 2, Pages 766-771

Improvement of Landfill Leachate Biodegradability with Ultrasonic Process

1National Institute of Health Research Tehran University of Medical Sciences, Tehran, Iran
2School of Public Health and Center for Environmental Research Tehran University of Medical Sciences, Tehran, Iran

Received 23 August 2011; Accepted 4 October 2011

Copyright © 2012 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Leachate from mature landfills is typically characterized by high ammonium (NH4+) content, low biodegradability (low BOD5/COD ratio) and high fraction of refractory and large organic molecules such as humic and fulvic acids. Mature leachate effluents are known to contain recalcitrant and/or non-biodegradable organic substances and biological processes are not efficient in these cases. A promising alternative to complete oxidation of biorecalcitrant leachate is the use of ultrasonic process as pre-treatment to convert initially biorecalcitrant compounds to more readily biodegradable intermediates, followed by biological oxidation of these intermediates to biomass and water. The objectives of this study are to investigate the effect of son catalysts process on biodegradability improvement. Results showed that when applied as relatively brief pre-treatment systems, the sonocatalysis processes induce several modifications of the matrix, which results in significant enhancement of its biodegradability. For this reason, the integrated chemical–biological systems proposed here represent a suitable solution for the treatment of landfill leachate samples with an efficient remediation of the relevant parameters (COD, TOC).