Urban wastewater treatment - Intensive chains

The Council Directive of May 21, 1991 concerning urban waste water treatment (91/271/EEC), also known as the Urban Waste Water Directive (UWWWD), aims to protect the environment from pollution by waste water from agglomerations. It requires EU member states to collect and treat their urban wastewater before discharging it into the natural environment.

The main requirements of the directive are as follows:

• wastewater collection and treatment: towns of all sizes are required to install wastewater collection systems. Alternative methods, such as autonomous sanitation, are authorized when justified by the situation;

• treatment standards: the directive sets performance standards for urban wastewater treatment plants (UWWTPs), depending on the size of agglomerations and the sensitivity of the areas receiving treated water;

• advanced treatment for sensitive areas: wastewater discharged into sensitive areas, such as eutrophic zones or areas where water quality is of particular importance, requires more advanced treatment;

• monitoring and reporting: Member States are required to monitor the quality of receiving and treated waters, as well as the efficiency of treatment systems. They are also required to report regularly to the European Commission on progress made in implementing the directive.

For France, as for other member states, applying and complying with this directive means investing in wastewater treatment and collection infrastructures, carrying out regular checks and adapting national legislation to European requirements. The major challenges currently facing France include improving existing systems, reducing untreated water discharges during exceptional rainfall events, and developing sustainable solutions tailored to specific local conditions.

Non-compliance with the directive can expose member states to infringement proceedings and substantial fines imposed by the European Commission.

This article is part of a set of three articles presenting the various wastewater treatment techniques that can be used to meet the requirements of the ERU Directive.

Wastewater treatment involves a variety of techniques, from the most traditional to the most advanced, each with its own specific features and application contexts.

This section covers

• physico-chemical treatments ;

• intensive biological treatment techniques.