Thesis in Thermo-rheological of sludge by ultrasonic metrology : energy performance and fouling diagnosis – THERBUS

Background of the position:

Road transport remains a major contributor to air pollution. While exhaust emissions have been significantly reduced through technological advances and the progressive electrification of vehicles, non-exhaust emissions—including brake, road, and tire wear—are increasingly recognized as dominant and still poorly characterized sources of pollutants. Among these, tire wear particles (TWPs) constitute a complex mixture of organic compounds, additives, and metals, emitted both in the particulate and semi-volatile phases1,2. TWPs accumulate in many environments (air, stormwater runoff or through bioaccumulation in vegetation and animals) and can be a major source of microplastics and heavy metals that are toxic to human and environmental health. Despite growing attention, important uncertainties remain regarding the chemical composition, atmospheric transformation, and environmental behavior of tire-derived emissions. In particular, the impact of atmospheric aging on their physicochemical properties—such as oxidation state, surface reactivity, and interaction with water—remains insufficiently understood3.

This collaborative PhD project between IMT Nord Europe and the Université de Lille (LASIRE UMR 8516 CNRS) aims to characterize tire wear particulate emissions from primary release to atmospheric evolution. The objectives are to (i) develop a method to quantify TWP and their selected additives using pyrolysis-GC-MS,

(ii) identify chemical tracers of TWPs in controlled and real-world samples,

(iii) investigate compositional and surface changes induced by aging, and

(iii) assess their hygroscopic properties.

At IMT Nord Europe, emissions from new and aged tires (summer, winter, and all-season) will be analyzed using complementary techniques including microchambers, TD-GC-MS, pyrolysis-GC-MS, and FTIR spectroscopy to determine molecular composition and functional groups. Samples collected in traffic-influenced environments will be studied to evaluate the relevance of identified tracers under realistic conditions. TWP’s metal content and distribution in the particles will be investigated using ICP-MS and surface-sensitive approaches. At LASIRE, particle morphology, elemental composition, degree of encrustation and surface characteristics will be examined using electron microscopy (MEB/EDX), while electron paramagnetic resonance (EPR) will be employed to identify persistent radical species formed during aging and assess their potential role in particle reactivity. The project will also examine how simulated and real environmental aging modifies the interaction of TWPs with water, providing insight into their evolving physicochemical properties in the atmosphere. Overall, this work will improve the mechanistic understanding of tire wear as an emerging source of urban air pollution and support its consideration in air quality studies.

Discipline: Fluid mechanics

Line Manager: Nadine LOCOGE

Workplace: Douai

Type of contract and duration: PhD contract during 36 months

CONTEXT :

Public establishment belonging to IMT (Institut Mines-Télécom), placed under the supervision of the Ministry of Economy, Finance and Industrial and Digital Sovereignty, IMT Nord Europe has three main objectives: providing our students with ethically responsible engineering practice enabling them to solve 21st century issues, carrying out our R&D activities leading to outstanding innovations and supporting territorial development through innovation and entrepreneurship. Ideally positioned at the heart of Europe, 1 hour away from Paris, 30 min from Brussels and 1h30 from London, IMT Nord Europe has strong ambitions to become a main actor of the current industrial transitions, digital and environmental, by combining education and research on engineering and digital technologies.

Located on two main campuses dedicated to research and education in Douai and Lille, IMT Nord Europe offers research facilities of almost 20,000m² in the following areas:

•              Digital science,

•              Energy and Environment,

•              Materials and Processes.

For more details, visit the School’s website : www.imt-nord-europe.fr

The position is vacant within the the Centre for Education, Research and Innovation in Energy and Environment (CERI EE) (https://recherche.imt-nord-europe.fr/energie-environnement-ceri/). The successful candidate will also become a member of the Complex Fluid Flows Laboratory, whose research focuses on complex fluids, complex flow phenomena, and their role in enhancing transport processes and process intensification.

CONTEXT AND OBJECTIVE :

The energy transition of wastewater treatment plants (WWTP) relies significantly on improving the performance of thermal exchanges within the facility. It is therefore crucial to optimize energy efficiency and minimize the fouling of heat exchangers. A primary example is the heat exchanger used for heating sludge under thermophilic conditions for anaerobic digestion, a key future pathway for material and energy recovery in WWTPs.

To ensure the efficiency of sludge-to-sludge exchangers and prevent fouling under high organic loads (4 kg VS/m3/d), precise knowledge of internal flow dynamics is essential. However, optimization is currently hindered by a major technological bottleneck: the total opacity of these particle-laden fluids prevents any optical access for conventional laser measurement tools. The objective of this thesis is to overcome this barrier through a purely experimental approach aimed at characterizing the thermo-rheology of sludge to diagnose fouling, using an innovative ultrasonic velocimetry (USV) metrological tool.

Partnerships and Institutional Framework

This thesis builds on the work carried out through an academic and industrial collaboration, which began in 2020 as part of the RHEOMETHA project, followed by i-TRANSBOUE in 2023. This partnership forms part of the Mocopée research program with the SIAAP. This is the Syndicat Interdépartemental pour l’Assainissement de l’Agglomération Parisienne, a public utility that transports and treats wastewater, rainwater and industrial effluent from the Paris metropolitan area every day. Established in 1970, it is the only interdepartmental water treatment authority in Europe and the first public utility operating across a European metropolitan area with the highest population density. Today, the SIAAP owns and operates six wastewater treatment plants, including the Seine Aval plant, which is the largest in Europe, carrying out comprehensive treatment of carbon, nitrogen and phosphorus using a variety of processes and technologies. The SIAAP also owns and operates a 440 km-long sewerage network. Finally, it monitors the quality of the Seine and the Marne within its operational area across several physico-chemical and biological parameters. The Innovation Direction is responsible for the scientific program of the SIAAP and for industrial innovation. Its mission is to support and guide the development of infrastructure, as well as operational and maintenance practices within the plants. It contributes to the company’s scientific and technical influence by disseminating its research and studies and by sharing the knowledge acquired through its InnEAUvation scientific program. The PhD will be carried out within the host laboratory, the Centre d’Enseignement de Recherche et d’Innovation Énergie Environnement (CERI EE) at IMT Nord Europe.

REQUIRED PROFILE :

Skills

Master 2 Research degree with a strong interest in applied scientific research.

Knowledge

Physics, Process and Bioprocess Engineering, and/or Fluid Mechanics.

Affinity for experimental work, proficiency in MATLAB, and knowledge of rheology, fluid dynamics, and heat transfer.

CONDITIONS :

The job is to be filled as to 01/10/2026 for a period of 36 month (temporary contract).