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The Scientific World Journal
Volume 2015, Article ID 850530, 8 pages
http://dx.doi.org/10.1155/2015/850530
Research Article

An Autopsy of Nanofiltration Membrane Used for Landfill Leachate Treatment

1Environmental Engineering Department, Istanbul Technical University, Maslak, 34469 Istanbul, Turkey
2National Research Center on Membrane Technologies (MEM-TEK), Istanbul Technical University, Maslak, 34469 Istanbul, Turkey
3ISTAC, Istanbul Environmental Management in Industry and Trade Inc., 34379 Istanbul, Turkey
4Nanoscience and Nanoengineering Department, Istanbul Technical University, Maslak, 34469 Istanbul, Turkey

Received 24 February 2015; Accepted 13 May 2015

Academic Editor: Ghadir A. El-Chaghaby

Copyright © 2015 Ibrahim Demir et al. 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.

Abstract

Komurcuoda leachate treatment plant, Istanbul, which consists of membrane bioreactor (MBR) and nanofiltration (NF) system, faced rapid flux decline in membranes after 3-year successful operation. To compensate rapid flux decline in membranes, the fouled membranes were renewed but replacement of the membranes did not solve the problem. To find the reasons and make a comprehensive analysis, membrane autopsy was performed. Visual and physical inspection of the modules and some instrumental analysis were conducted for membrane autopsy. Membranes were found severely fouled with organic and inorganic foulants. Main foulant was iron which was deposited on surface. The main reason was found to be the changing of aerator type of MBR. When surface aerators were exchanged with bottom diffusers which led to increasing of dissolved oxygen (DO) level of the basin, iron particles were oxidized and they converted into particulate insoluble form. It was thought that probably this insoluble form of the iron particles was the main cause of decreased membrane performance. After the diagnosis, a new pretreatment alternative including a new iron antiscalant was suggested and system performance has been recovered.