Wastewater reuse in Turkey: from present status to future potential Bilgehan Nas , Sinan Uyanik , Ahmet Aygün, Selim Dog ̆ an, Gürsel Erul, K. Batuhan Nas, Sefa Turgut, Mustafa Cop and Taylan Dolu ABSTRACT The Ministry of Environment and Urbanization (MoEU) initiated an important project, ‘Reuse of Treated Wastewater in Turkey’, in 2017. With this project, all wastewater treatment plants (WWTPs) were investigated to determine wastewater reuse purposes for the first time. The results obtained from this project were that although there are 1,015 existing WWTPs, only 15 of them realized wastewater reuse. In 2017, the total volume of reused treated wastewater in Turkey amounted to 29.6 million m 3 /year, accounting for 0.78% of the treated urban wastewater. With the present water potential and sectoral water use rates, Turkey should make key administrative and technical regulations in the coming years for water reuse. This paper aims to give an overview of wastewater reuse activities from present status to future potential in Turkey and the opportunities and challenges in expanding water reuse. The status of WWTPs, treatment processes and their compliance with the WWTPs where reuse is carried out in Turkey are evaluated in this study. The realization of the planned goals and challenges are discussed after regulatory changes in Turkey for reclaimed wastewater and reuse targets for 2023. Bilgehan Nas (corresponding author) Selim Dog ̆ an Taylan Dolu Department of Environmental Engineering, Konya Technical University, Konya, Turkey E-mail: bnas@ktun.edu.tr Bilgehan Nas K. Batuhan Nas Sefa Turgut Mustafa Cop Arbiotek Environmental Solutions Research and Development Ltd Co., Selcuk University Technology Development Zone, Konya, Turkey Sinan Uyanik Department of Environmental Engineering, Harran University, Ş anlıurfa, Turkey Ahmet Aygün Department of Environmental Engineering, Bursa Technical University, Bursa, Turkey Gürsel Erul Ministry of Environment and Urbanization, General Directorate of Environmental Management, Ankara, Turkey K. Batuhan Nas Sefa Turgut Graduate School of Natural Sciences, Konya Technical University, Konya, Turkey Key words | advanced treatment, reclaimed water, wastewater, wastewater regulations, water reuse INTRODUCTION The world population is expected to be 9.7 billion and 10.9 billion by the years 2050 and 2100 respectively based on medium-variant projection according to the World Popu- lation Prospects 2019 report published by the United Nations (UN ). Both the limited water resources and increase in demand for these resources all over the world in parallel with rapid population growth are considered, and the necessity of reusing water which actually has been applied via different techniques since ancient times (Angelakis et al. ) has become unavoidable in today’s conditions in order to increase the water supply. The sol- utions of water reuse remain limited in comparison with their potential. The goal is to encourage using resources effi- ciently and reduce the pressure on water scarcity by fostering the development of safe reuse (Alcalde-Sanz & Gawlik ). Water reuse presents a potential for water management and contributes to reducing fresh water use. On the other hand, contribution to sustainable water management and resource 73 © IWA Publishing 2020 Water Supply | 20.1 | 2020 doi: 10.2166/ws.2019.136 Downloaded from http://iwaponline.com/ws/article-pdf/20/1/73/646686/ws020010073.pdf by guest on 18 July 2022