Industrial wastewater in the context of European Union water reuse legislation and goals

Water pollution and freshwater scarcity are growing problems not only in Europe but all over the world. Water reuse contributes significantly to water sustainability and brings many environmental, economic, and social benefits. The European Union (EU) has recently been addressing water-related problems with great commitment. Unfortunately, the total production of wastewater in the European Union is unknown. The situation in the EU is not satisfactory, as only 2.5% of treated wastewater is reused. The first contribution of this study is the estimation of the total amount of wastewater produced annually in the EU. It is estimated that half of this amount comes from industry, namely over 25,500 million m3. Therefore, this study aims to review and analyze the current state of the industrial wastewater (IWW) issue in the EU and to put it in the context of current EU legislation, targets, and water reuse policy. Moreover, since water reuse technologies are energy intensive, the focus is given to the techno-economic impact of IWW reuse. The energy consumption and investment costs in relation to the amount of water treated have been determined for filtration only, minimum liquid discharge (MLD), and zero liquid discharge (ZLD) systems. Reclaiming 80% of IWW would increase industrial energy consumption by only 4.1%, and investment costs would amount to only 1.5% of the EU GDP. Further, the assessment was focused on the paper & pulp industry, which is among the largest wastewater producers. Implementing efficient water reuse technology in this industry could mean up to 3,449 Mm3/year of reclaimed water.