An Autopsy of Nanofiltration Membrane Used for Landfill Leachate Treatment.

Ibrahim Demir,Serkan Guclu,Senol Yildiz,Turker Turken,Vahit Balahorli,Suphi Caglar,Mehmet E Pasaoglu,Ismail Koyuncu,Recep Kaya,Reyhan Sengur-Tasdemir

doi:10.1155/2015/850530

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.

Highlights

Membrane processes have many advantages due to their modular designs, small footprints, and automated operations [1]
Membrane fouling control is an important subject and effective fouling control can be verified by membrane autopsy [5]
This may be related to the high pressure drop between the entrance and exit

Summary

Introduction

Membrane processes have many advantages due to their modular designs, small footprints, and automated operations [1]. These 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. 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]. Membrane fouling control is an important subject and effective fouling control can be verified by membrane autopsy [5]

Methods

Results

Conclusion