Desalination

246 (2009)409–416

Current situation of urban wastewater treatment plants

in megacity Istanbul

Idil Arslan-Alaton*, Gulen Iskender, Aysegul Tanik, Melike Gurel,

Suleyman Ovez, Derin Orhon

Department of Environmental Engineering, Faculty of Civil Engineering, Istanbul Technical University, ITU,

34469 Maslak, Istanbul, Turkey

Tel. +90 212 285 3786; Fax: +90 212 285 3781; email: arslanid@itu.edu.tr

Received 05 September 2007; revised 15 April 2008; accepted 22 April 2008

Abstract

Within the framework of a European Union-funded project, a comprehensive questionnaire has been preparedand a survey has been realized among the already existing urban wastewater treatment plants of the country withthe aim of investigating the reuse possibility of treated effluents. This study forming one of the project milestones,aimed at putting forth the existing situation of the urban wastewater treatment plants of the Greater MetropolitanIstanbul which is one of the most crowded cities of the world. The current situation revealed that as the city hasscarce available land and is surrounded by sea, primary treatment is favored. Some of the plants own biologicaltreatment units where the effluents comply with the discharge to receiving water standards. Most of the plantsserve to populations over 100 000 and face operational problems such as lack of automation, clogging of pipes,old-fashioned equipment and working over-capacities. The Water and Sewerage Administration of Istanbul(ISKI) has to supply high quality drinking water to the inhabitants of the city and is responsible for the treatmentof the urban wastewater. ISKI has started to initiate not only secondary but also advanced biological treatmentunits to the already existing plants and urges the companies in charge of their construction to operate the plantsfor 20 years.

Keywords:Urban wastewater treatment plants; Primary treatment; Biological treatment; Advanced biological

treatment; Marine discharge systems; Istanbul

1. Introduction

Istanbul is one of the highly populated citiesof the world facing unplanned and uncontrolled

*Corresponding author.urbanization. With regard to its strategic geo-graphical location, climatic conditions, ease oftransportation and employment opportunities,almost half of the industries in the country are set-tled within and/or in the vicinity of this metropo-lis. The population of Istanbul in 2007 has been

Presented at the: MEDA WATER International Conference on Sustainable Water Management, Tunis, March 21–24 2007.

0011-9164/09/$– See front matter © 2009 Elsevier B.V. All rights reserved.doi:10.1016/j.desal.2008.04.055