PhD opportunities

Remediation of soil polluted with oxyanions, sensitivity to exposure scenarios and waste management regulations

Thesis proposal

Area of expertiseGeoscience and Geoengineering
Doctoral SchoolGRNE - Géosciences, Ressources Naturelles et Environnement
SupervisorM. Laurent DE WINDT
Research unitGeosciences
ContactDE WINDT Laurent
Starting dateOctober 1st 2021
Keywordswastes, environmental engineering, geomaterials, soil
AbstractSoil remediation and decontamination is a growing demand and comes with high stakes in terms of public health and environmental protection. Landfill of excavated soil from civil engineering construction, contaminated with sulfate and or heavy metals, obeys to strict regulation. The more the soil is considered dangerous, the more the regulations for landfill or valorization are stringent thus making the management of such waste costly. The Solidification / Stabilization (S/S) of the contaminants with hydraulic binders is an interesting path of valorization, for economic and environmental considerations.
Since many years, LafargeHolcim (LH) develops solutions for soil remediation. Efficient binders have already been patented for Sulfates, Pb, Zn…, and for more complex cases such as oxyanions that are commonly observed in industrial polluted sites (Cr, Mo, Sb, Se). However, for oxyanions some optimization is still needed to cope with redox conditions. All the more, environmental regulations vary from one country to another, and especially the way to assess the durability of these treated material. A better understanding of the sensitivity of these material to exposure conditions (acidic, carbonation, redox,) is necessary, to optimize the S/S recipe in order to fulfill local environmental regulation. The Geosciences Dpt. of MINES ParisTech (French high education institution in engineering) has acquired an international recognition in the development of multiphase reactive transport modeling (HYTEC code) and application to hazardous and radioactive waste management, environmental impact, water resource decontamination, geomaterial durability...
Objectives of the Ph.D:
• Part 1) Review and optimization of existing S/S mix design for oxyanions;
• Part 2) Parameter sensitivity vs. granularity, hydric context pH, redox transient stage, carbonation;
• Part 3) Optimization of S/S process vs. a) the leaching procedures used in local regulations (Europe, North America, …), b) the exposure scenarios (landfill, re-use).
The S/S soil optimization, leaching experiments, possibly including a small-scale pilot, and aqueous/solid phase characterizations will be performed in the LH Research Center. The modeling of the leaching tests and long-term exposure scenarios will be developed at MINES ParisTech. Collaboration with the US Vanderbilt School of Engineering (Environmental Laboratory, Pr. D. Kosson) is part of the PhD project with a scientific stay of several months.
ProfileMaster’s degree in Civil or Environmental Engineering, in Chemistry or Material Sciences and Engineering, possibly in Geochemistry.
Fluent in English (good knowledge in French would be a plus), strong ability for independent work and original thought in a team working network, clear interest in industrial and applied researches.
FundingConvention CIFRE