Mixing zone regulation for effluent discharges into EU waters

Abstract

Environmental standards and their implementation in different countries are reviewed for point source discharges into surface waters. The paper focuses on the analysis of existing mixing zone regulations and recommends procedures to develop and manage mixing zone definitions as required by recent amendments of the ‘combined approach' of the European Community water framework directive. The review shows that only a few mixing zone regulations exist in the European Union member countries, and that some effluent types, such as desalination brine discharges, and some discharge technologies, such as river diffusers, are not yet considered. The paper discusses those two issues in detail. First, by analysing desalination plant discharge characteristics and recommending mixing zone regulations for such multi-component and multi-process discharges. Second, by presenting river diffuser discharge technologies and procedures for demonstrating compliance of discharges that employ these technologies.