Wastewater reuse: what will the new European regulation change?

Reusing wastewater to save freshwater is one of the virtues of "reuse". This approach is an essential lever in a context where global warming is increasing pressure on water resources.

Julie Mendret, University of Montpellier

In France, however, only 0.6% of wastewater is treated. This pales into insignificance when compared with other European neighbors, such as Italy, which treats 8% of its wastewater, and Spain, which treats 14%. Why is our country lagging behind? The main reasons for this French phenomenon are a lack of public awareness and strict regulations.

In France, the reprocessing and reuse of treated wastewater is governed by two ministerial decrees from 2010 and 2014. These regulations define four levels - A, B, C, or D, from best to worst - with water quality requirements and authorized and prohibited uses for each. For example, crops eaten raw can only be irrigated with water of quality level A.

In addition, depending on the irrigation technique used, there are constraints such as wind speed, minimum safety distances from dwellings or watercourses, and public information requirements...

Regulatory obstacles

While these strict regulations are necessary in terms of health and the environment, the constraints inherent in their application complicate the preparation of applications, and even jeopardize projects.

Several of them were aborted due to constraints in setting them up (dossier preparation, land typology constraints, specific requirements for sprinkler irrigation, etc.) and implementing them (traceability requirements, water quality monitoring, irrigation program management, etc.).

A new European regulation

How can these projects be prevented from taking on water in the face of regulatory obstacles? This is the aim of the new European regulation of June 5, 2020 on the reuse of wastewater, which aims to promote reuse by harmonizing application rules on a European scale.

The European Parliament points out that the new rules:

The aim of these "wastewater treatment" regulations is to ensure that treated wastewater is reused to a greater extent, so as to limit the use of water bodies and groundwater. Falling groundwater levels, due in particular to agricultural irrigation, but also to industrial use and urban development, are one of the main threats to the EU's aquatic environment".

The stated aim is to increase the volume of reuse from 1.7 billion cubic meters per year to 6.6 billion, thereby reducing water stress in the EU by 5% by 2025.

The European regulation concerns only agricultural irrigation - other uses remain the responsibility of the Member State; Member States have three years to bring their installations into line.

More flexible than the French framework

This new regulation is more flexible than the current French framework: the four water quality classes are maintained - with reinforced microbiological thresholds (for the Escherichia Coli criterion, French quality A corresponds to quality C in the new regulation) - but performance targets are no longer required, except for quality A. To compensate, the frequency of health checks - which vary according to water class - has been increased.

Another major advance: the compulsory usage constraints linked to distance, soil type and wind speed have disappeared. In their place, "barriers" have been introduced - an additional treatment, for example - enabling quality criteria to be adapted according to risk.

The treatment plant operator must propose a risk management plan identifying the risks and the means implemented to manage them (replacing the French rules of use that have been mandatory until now). Once validated, this plan will enable an operating permit to be obtained, specifying, among other things, the water quality class delivered and the authorized agricultural use.

The risk management plan drawn up by the wastewater treatment plant operator is one of the cornerstones of the new regulations.

It allows each project to be considered on a case-by-case basis, and provides greater flexibility in setting up reuse projects. It also includes a public awareness component, encouraging the publication of certain data (quality of recycled water, test results, etc.) to reassure consumers and improve social acceptance of reuse, which is already on the rise. Today, 83% of French people say they are prepared to drink drinking water produced from wastewater.

Harmonization and questions

In some respects, the European regulation of June 5, 2020 represents a real step forward. Practices and quality levels will be the same in all Member States, with usage constraints adapted to actual risks and greater transparency for consumers.

However, this new regulation considers only one use - irrigation. It is to be hoped, however, that this will eventually provide an opportunity to democratize other uses in France, such as golf course and park irrigation, fire-fighting and groundwater recharge.

However, very high quality requirements can lead to additional costs for plant upgrades, particularly if an additional treatment stage has to be added. In some cases, this obstacle cannot be overcome without public support.

Lastly, these regulations do not mention certain categories of pollutants of great concern (microplastics and pharmaceutical micropollutants, for example), which are a source of concern for consumers and for which the advanced treatments must generally be implemented.

Julie Mendret, Senior Lecturer, HDR, University of Montpellier

This article is republished from The Conversation under a Creative Commons license. Read theoriginal article.