ORGANISATION/COMPANYUniversité Gustave Eiffel
RESEARCH FIELDEnvironmental science › Water science
RESEARCHER PROFILEFirst Stage Researcher (R1)
APPLICATION DEADLINE21/03/2022 17:00 - Europe/Brussels
LOCATIONFrance › Marne-La-Vallée
TYPE OF CONTRACTTemporary
HOURS PER WEEK35
OFFER STARTING DATE03/10/2022
EU RESEARCH FRAMEWORK PROGRAMMEH2020 / Marie Skłodowska-Curie Actions COFUND
MARIE CURIE GRANT AGREEMENT NUMBER101034248
Cementitious materials are one of the most widely used materials in the collection and treatment of wastewater. These materials have a significant chemical resistance, which is an important characteristic since it allows the appropriate treatment of wastewater, the creation of a durable network and the prevention of pollution. The presence of sulphur and nitrogenous elements associated with micro-organisms can induce important degradations of cementitious materials. The main mechanisms are related to hydrate alteration and mineralogical transformations by ion exchange.
In the case of sulphur elements, these are reduced in the submerged part (bottom) of the pipe by sulphate-reducing microorganisms and will generate H2S which will degas in the aerial part of the network. This H2S will condense on the surface and be oxidized by sulfo-oxidizing microorganisms. This oxidation will lead to the formation of sulfuric acid which will react with the cement matrix to form ettringite and gypsum (De Windt, 2010; George, 2013; Herisson, 2013; Yuan, 2015; Sawadogo, 2021) leading to swelling, disintegration of the material and a significant modification of its initial properties.
In the case of nitrogenous elements, wastewater treatment plants must limit their nitrogen discharges into the natural environment. To do so, they use biological processes of nitrification that allow the oxidation of ammonium into nitrite ions and then into nitrates through the use of nitrifying bacteria. The concentrations of nitrogenous compounds in the effluents to be treated are not considered aggressive for cementitious materials according to EN 206 standard. However, the biofilm forming on the surface produces local modifications of the environment leading to a decalcification of the cement matrix. To date, very little research has been carried out on this subject and the mechanisms of degradation remain poorly understood in order to propose perennial solutions to the operators.
The understanding of the physico-chemical processes and of the observed degradations is currently based on in-situ collected samples, with punctual measurements carried out in laboratory (optical microscopy, SEM, XRD essentially). If the degradations are rather easy to note, the physicochemical processes which govern them and their kinetics remain difficult to apprehend. Very little research has been carried out on the impact of nitrification and the phenomena at the origin of these degradations are little known.
The objective of the thesis is to better appreciate the processes of bio-alteration of a cement matrix, as well as its propagation kinetics in the matrix in the case of these two attacks. It is also a question of better apprehending the degradation on the surface and the appearance of the mineral phases revealing the process. The approach will be based on the exposure of cement matrices in biodegradation chambers in the presence of H2S and in nitrification bioreactors controlled by a choice of microorganisms, in collaboration with the MIT Spectroscopy Laboratory. It is then a question of selecting given microorganisms in order to appreciate and to quantify their contributions to the bio-alteration process of cement matrices. To this approach will be added a follow-up of the bio-alteration process by vibrational spectroscopy (FTIR and Raman).
Raman spectroscopy will be specifically implemented for a continuous monitoring of a mineralogical and a chemical evolution of the cementitious matrix. Specific Raman probe developments, such as ones capable of being immersed in chemically aggressive environments, will be developed with MIT. MIT lab has pioneered miniature optical fiber probes for Raman spectroscopy which has been successfully applied to biomedical applications such as integrating with cancer biopsy needles or epidural needles. In addition, since the data obtained from Raman spectroscopy is abundant, the implementation of statistical data analysis methods (such as PCA, MCR-ALS and ICA), are envisaged with MIT.
In addition to this research conducted in controlled biological environments, cementitious matrices will be exposed to effluents in sewage networks for several months under real conditions. This phase of the thesis work will be done in cooperation with the Syndicat Interdépartemental pour l'Assainissement de l'Agglomération Parisienne (SIAAP).
- High-quality doctoral training rewarded by a PhD degree, delivered by Université Gustave Eiffel
- Access to cutting-edge infrastructures for research & innovation.
- Appointment for a period of 36 months based on a salary of 2 700 € (gross salary per month).
- Job contract under the French labour legislation in force, respecting health and safety, and social security: 35 hours per week contract, 25 days of annual leave per year.
- International mobility will be mandatory
- An international environment supported by the adherence to the European Charter & Code.
- Access to dedicated CLEAR-Doc trainings with a strong interdisciplinary focus, together with a Career development Plan.
- At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree. At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.
- At the time of the deadline, applicants must be in the first four years (full-time equivalent research experience) of their research career (career breaks excluded) and not yet been awarded a doctoral degree. Career breaks refer to periods of time where the candidate was not active in research, regardless of his/her employment status (sick leave, maternity leave etc). Short stays such as holidays and/or compulsory national service are not taken into account.
- At the time of the deadline, applicants must not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months in the 3 years immediately prior to the call deadline.
- Applicants must be available to start the programme on schedule (around 1st October 2022).
- Please refer to the Guide for Applicants available on the CLEAR-Doc website.
- The First step before applying is contacting the PhD supervisor. You will not be able to apply without an acceptation letter from the PhD supervisor.
- Please contact the PhD supervisor for any additional detail on job offer.
- There are no restrictions concerning the age, gender or nationality of the candidates. Applicants with career breaks or variations in the chronological sequence of their career, with mobility experience or with interdisciplinary background or private sector experience are welcome to apply.
- Support service is available during every step of the application process by email: firstname.lastname@example.org
Web site for additional job details
REQUIRED LANGUAGESENGLISH: Excellent
- At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree.
- At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.
International mobility: a secondment at MIT (USA). For more information, contact the PhD thesis supervisor.
EURAXESS offer ID: 716447
The responsibility for the jobs published on this website, including the job description, lies entirely with the publishing institutions. The application is handled uniquely by the employer, who is also fully responsible for the recruitment and selection processes.
Please contact email@example.com if you wish to download all jobs in XML.