Research Article An Autopsy of Nanofiltration Membrane Used for Landfill Leachate Treatment Ibrahim Demir, 1 Ismail Koyuncu, 1,2 Serkan Guclu, 1,2 Senol Yildiz, 3 Vahit Balahorli, 3 Suphi Caglar, 3 Turker Turken, 1,2 Mehmet E. Pasaoglu, 1,2 Recep Kaya, 1,2 and Reyhan Sengur-Tasdemir 2,4 1 Environmental Engineering Department, Istanbul Technical University, Maslak, 34469 Istanbul, Turkey 2 National Research Center on Membrane Technologies (MEM-TEK), Istanbul Technical University, Maslak, 34469 Istanbul, Turkey 3 ISTAC, Istanbul Environmental Management in Industry and Trade Inc., 34379 Istanbul, Turkey 4 Nanoscience and Nanoengineering Department, Istanbul Technical University, Maslak, 34469 Istanbul, Turkey Correspondence should be addressed to Ibrahim Demir; idemir@itu.edu.tr Received 24 February 2015; Accepted 13 May 2015 Academic Editor: Ghadir A. El-Chaghaby Copyright © 2015 Ibrahim Demir et al. Tis 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. Komurcuoda leachate treatment plant, Istanbul, which consists of membrane bioreactor (MBR) and nanofltration (NF) system, faced rapid fux decline in membranes afer 3-year successful operation. To compensate rapid fux decline in membranes, the fouled membranes were renewed but replacement of the membranes did not solve the problem. To fnd 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. Te main reason was found to be the changing of aerator type of MBR. When surface aerators were exchanged with bottom difusers 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. Afer the diagnosis, a new pretreatment alternative including a new iron antiscalant was suggested and system performance has been recovered. 1. Introduction Membrane processes have many advantages due to their modular designs, small footprints, and automated opera- tions [1]. Tese advantages increased their usage within very wide range of applications in water and wastewater treatment. Despite this wide usage, membrane lifetime limits the sustainability of the membrane processes. Widespread use of membranes is still restricted because of membrane fouling phenomena [2]. Membrane lifetime and performance are afected by many factors such as selection of proper process membrane material and operating parameters. Mem- brane performance losses can be recognized by low efu- ent rates, decreased rejection, high pressure drop between inlet and outlet, and frequent cleaning requirement [3]. Optimum operation conditions decrease replacement period and operating costs and increase membrane performance. Another option to increase the lifetime of the membrane is to apply pretreatment [4]. However, fouling is one of the biggest problems in membrane area which negatively efects membrane performance. Membrane fouling control is an important subject and efective fouling control can be verifed by membrane autopsy [5]. Renewal of membranes can be due to membrane clogging or complete lifetime. Membrane autopsy may help to extend membrane lifetime. Membrane autopsy can be thought of as starting point for problem determination. It also gives information about optimum operating conditions, chemi- cal cleaning efectiveness, and the efects of infuent water characteristics on membrane performance. According to the studies, generally membranes encounter biofouling, metal oxide fouling, oxidation, abrasion, and clay and mineral Hindawi Publishing Corporation e Scientific World Journal Volume 2015, Article ID 850530, 8 pages http://dx.doi.org/10.1155/2015/850530