- Lieu de travail: Rennes – Bretagne – France
- Intitulé du sujet: Optimisation and evaluation of a hybrid ozonation/nanofiltration process for the reuse of urban wastewater in the context of indirect potabilisation
- Champs scientifiques: Sciences de l’ingénieur; Chimie
- Mots clés: Indirect potable reuse, nanofiltration, ozonation, waste water, reuse
Description du sujet
he Oxymore project involves the reuse of wastewater in coastal areas, as part of the first indirect drinking water production demonstrator in Europe, commissioned by Vendée Eau. Indirect drinking water treatment involves the replenishment of surface water reserves with finely-treated wastewaters, which are then used to supply drinking water production plants. Consequently, the production of high-quality, pathogen-free water containing low concentrations of trace organic contaminants (TrOCs) is necessary.
The project aims to evaluate two hybrid ozonation-nanofiltration (HONF) processes as more sustainable alternatives to the low-pressure reverse osmosis (LPRO) used on the demonstrator, in order to minimize energy and environmental footprints. HONF involves the simultaneous oxidative degradation and retention of organic matter and TrOCS. The added value of this coupling lies in its ability to reduce the drawbacks of each process, in particular a decrease of the membrane fouling and the rejection of the oxidation by-products formed during the ozonation stage.
The first HONF process, developed by the IEM Montpellier, uses ozone-enriched gas bubbles introduced into the NF cell containing a catalytic ceramic membrane. The second process, developed in Rennes, uses pre-ozonated water mixed with H2O2-doped wastewater, leaving the door open to the use of organic membranes. It is more specifically on this second process that the doctoral student recruited will be involved.
Work program
A detailed characterisation (ions, TrOCs, organic matter) of the effluent to be treated, taking into account seasonal variations, will be carried out. The organic matter in the effluent will be fractionated and carefully analysed by the IC2MP in Poitiers. Lyophilized fractions will then be used to construct a synthetic water model, with a chemical composition identical to that of the industrial effluent. This synthetic water model will be used at the beginning of the thesis for a laboratory study dedicated to the optimization of HONF process.
A scale-up will then be carried out on-site with monitoring for several months in parallel with the existing LPRO process. Detailed characterization of the organic matter and its evolution during the treatment will enable the rejection and oxidation mechanisms to be identified and understood. Mass spectrometry will be implemented to assess TrOCs removal efficiency and the formation of oxidation by-products. These chemical analyses will be combined with bioassays (carried out by INSERM Montpellier) to monitor the toxicity and ecotoxicity of the feed and of the permeates and retentates produced on-site. In addition to the validation of the performances of each configuration on a real wastewater, these long-term tests will allow to assess the ageing of the membranes and set up cleaning in place procedures.
These characterisations will be used as inputs for a technico-economic study (carried out as part of this thesis) and an environmental impact study (carried out by UniLasalle Rennes).
Partnership and financial support
This doctoral contract is funded by the French National Research Agency (OXYMORE collaborative research project – 670 kEuros). The Oxymore project brings together the expertise of 5 public and private academic teams:
The Rennes Institute of Chemical Sciences (ISCR, host laboratory for the doctoral student recruited);
The European Membrane Institute (IEM) in Montpellier, which will host a post-doc in charge of developing a second hybrid ozonation/nanofiltration process;
The Poitiers Chemistry Institute: materials and natural ressources (IC2MP), in charge of the fractionation, concentration and characterisation of natural organic matter in water;
Institute of Cancer Research of Montpelier (IRCM, INSERM), in charge of bioassays;
UniLasalle Rennes, which will be in charge of the environmental impact study.
Within this consortium, Vendée Eau, the public company responsible for managing and distributing drinking water throughout the Vendée department, occupies a central position.Within this consortium, Vendée Eau, the public company responsible for managing and distributing drinking water throughout the Vendée department, occupies a central position.Within this consortium, Vendée Eau, the public company responsible for managing and distributing drinking water throughout the Vendée department, occupies a central position
Prise de fonction :
01/09/2025
Nature du financement
Autre financement public
Précisions sur le financement
PrĂ©sentation Ă©tablissement et labo d’accueil
Institut des Sciences Chimiques de Rennes UMR 6226 CNRS – UniversitĂ© de Rennes 1
The ISCR’s ambition is to conduct top-level research in its core business: the design, synthesis and characterisation of molecules and functional materials. The areas of research cover a wide range of applications: health, materials, optics and telecommunications, energy and the environment.
With the ISCR The Chemistry and Process Engineering (CIP) team brings together around fifty people (lecturer-researchers, engineers, technicians, doctoral students, post-doctoral fellows, etc.) from the École Nationale Supérieure de Chimie de Rennes, the University of Rennes and the Centre National de la Recherche Scientifique (CNRS). Their research focuses on the study and design of sustainable processes for the treatment of pollution, as well as production in the key fields of the environment, agri-food and chemistry. The team also develops analytical methodologies for the evaluation of trace pollutants and the characterization of interfaces in order to determine the performance of these processes.
Site web :
https://iscr.univ-rennes.fr/chemistry-and-process-engineering-cip
Intitulé du doctorat
Doctorat mention chimie
Pays d’obtention du doctorat
France
Etablissement délivrant le doctorat
Université de Rennes
Ecole doctorale
École Doctorale S3M N° 638 (Sciences de la Matière, des Molécules et Matériaux)
Profil du candidat
5 years’ higher education (engineering school and/or Masters II) in process engineering and/or water chemistry. At least theoretical knowledge of analytical chemistry (liquid chromatography, ion chromatography, mass spectrometry, etc.) is also required, and practical experience in HPLC would also be appreciated.
Particular attention will be paid to the experimental skills of the candidate, who should have done sufficient practical chemistry work during their training.
Motivation for academic research.
Good communication and coordination skills with different partners.
Fluency in French and English (written and spoken). B2 level required.
Ability to present results both orally and in writing.
Ability to summarise (a bibliographic summary is required).
Willingness to travel (a period of several months on-site in Les Sable d’Olonne is required). Driving licence would be appreciated.Date limite de candidature
30/04/2025
