Q&A

LIFE ZEUS is a European project dedicated to water reuse in the agri-food industry. It aims to demonstrate, under real industrial conditions, that it is possible to greatly reduce water withdrawals and discharges through stream separation, membrane treatments and water reuse on the production site.

The demonstrator is installed at the MONIN site in Bourges. The project brings together CHEMDOC, MONIN, INSA Toulouse and the International Office for Water.

LIFE ZEUS brings together four complementary partners:

• CHEMDOC, project coordinator and specialist in membrane treatment technologies;
• MONIN, which hosts the demonstrator at its industrial site in Bourges;
• INSA Toulouse, which contributes its scientific and technical expertise;
• the International Office for Water (OiEau), involved in particular in water quality monitoring, impact assessment and the dissemination of results.

This complementarity makes it possible to address the technical, health, environmental and economic dimensions of the project simultaneously.

No. The Bourges site serves as an industrial demonstrator, but one of the project's objectives is precisely to produce knowledge, methods and solutions that can be transferred to other companies.

Each site nevertheless has its own specific features: activity, processes, effluent quality, water needs, health constraints, availability of the resource and applicable regulations. A REUSE project must therefore always be adapted to the local context.

Zero liquid discharge is the ambition that gave the project its name: ZLD — Zero Liquid Discharge.

This approach seeks to push water reuse and the recovery of residual streams as far as possible. Above all, the project makes it possible to study, under industrial conditions, how far this approach can be taken while taking into account technical, health, environmental and economic constraints.

Water is essential for many uses: manufacturing, cleaning, rinsing, cooling or the production of utilities. In a context of growing pressure on the resource, reuse makes it possible to limit withdrawals of fresh water and reduce the volumes discharged.

However, the aim is not to reuse water at all costs: water quality must always be suited to its use and compatible with health and regulatory requirements.

REUSE refers in general to the reuse of water. In the agri-food industry, it can concern several types of water: recycled water from raw materials, recycled process water and recycled treated wastewater.

REUT, or the recycling of treated wastewater, corresponds only to this last category: wastewater that has been treated before being reused.

No. Whether water can be reused depends on its origin, its quality and the use for which it is intended.

The regulatory framework distinguishes in particular between uses with direct contact, indirect contact and no contact with foodstuffs. Quality requirements are adapted to these different situations.

The first step is to have a good understanding of the site's water uses and flows: where the water comes from, where it is used, in what quantity, at what quality and where it goes afterwards.

This mapping makes it possible to identify potential savings and the streams that could be reused. It then makes it possible to match an available resource to a water need, by looking for the level of treatment that is actually required.

No. The treatment must be adapted to the quality of the water available and to that required for the new use.

In some cases, a short recycling loop may require relatively simple treatment. For more demanding uses or for the reuse of treated wastewater, several steps may be necessary: filtration, microfiltration, nanofiltration, reverse osmosis or UV disinfection.

The challenge is therefore not to over-treat the water, but to produce the necessary quality in the right place.

The LIFE ZEUS demonstrator relies in particular on membrane separation technologies: microfiltration, nanofiltration and reverse osmosis. UV disinfection systems also help to secure certain loops.

The project also works on stream separation and on the recovery of brines from the regeneration of water softeners, in order to limit saline discharges.

Not all effluents have the same characteristics. Mixing a lightly loaded stream with a highly concentrated one can make its treatment and recovery much more difficult.

LIFE ZEUS is therefore based on a logic of separation at source: keeping streams as homogeneous as possible so that the most suitable treatment can be applied to each one and their reuse or recovery made easier. The separate treatment of saline streams is in particular an important principle of the project.

Treated water can be reused in the factory when its quality is compatible with the intended use.

LIFE ZEUS therefore no longer systematically regards water leaving a process as waste: it can become a new resource for the industrial site. This approach makes it possible to create reuse loops and to reduce the use of fresh water.

Membrane technologies separate water from some of the substances it contains. They therefore generate a stream of purified water and a more concentrated stream.

The management of these concentrates is an integral part of the project. In particular, LIFE ZEUS seeks to recover organic matter and salts rather than simply shifting pollution from one stream to another.

Yes. Control of water quality is a central element of the project.

The system relies on analyses, online measuring instruments and monitoring of operating parameters. In particular, the project provided for the definition of quality parameters, their monitoring and a specific surveillance plan.

Yes. Since 2024, France has had a specific framework for the reuse of certain types of water in food-sector companies.

It is based in particular on Decree No. 2024-33 of 24 January 2024, Decree No. 2024-769 of 8 July 2024 and the Order of 8 July 2024. These texts specify the categories of reused water, the uses concerned, the quality requirements and the applicable administrative procedures.

It depends on the type of water reused.

The reuse of water from raw materials or process water is subject to a declaration procedure, in particular with integration into the food safety management plan.

The production and use of recycled treated wastewater, on the other hand, require prior authorisation.