Frontignan-la-Peyrade: Completion of remediation work on the site of the former refinery

The Challenge: Breathing New Life into an Industrial Site in the Heart of a Densely Built-Up Urban Area

The former Frontignan-la-Peyrade refinery bore the marks of decades of oil production: contaminated soil, compromised groundwater, and pyrotechnic risks resulting from World War II bombings. Since the site was immediately adjacent to residential areas, the remediation required not only first-rate technical expertise but also strict control of any disruption to local residents.

This project of European scope, launched in the summer of 2022, was entrusted to Séché Environnement Services (SES). It was completed in the spring of 2025 with the official handover of the site to the city of Frontignan.

A Mobile Protective Tent

In light of the risks of odor nuisance and dust dispersion, the teams developed an innovative solution: an inflatable protective tent measuring 120 m × 50 m, weighing 60 metric tons, and featuring an integrated air treatment system.

The innovation lies not only in its size but also in its mobility: We have relocated it 17 times over the course of four years without dismantling it. This ability to keep pace with construction progress in real time made it possible to maintain optimal conditions for local residents while meeting project deadlines—a technical feat that has become a symbol of this project.

Groundwater Management: Customized Engineering Services

The groundwater, which was already present at a depth of 2 meters and extended to a depth of up to 4 meters during excavation, posed one of the project’s greatest technical challenges.

A special treatment plant with a capacity of 80 m³/hour was installed on site, comprising a flexible water tank with a capacity of 300 m³ and a storage basin with a capacity of 1,000 m³. Most of the treated water was reused on the construction site—for watering the roadways, washing machinery, and for technical purposes—which significantly reduced the consumption of drinking water.

The Discovery of a 250-kg Shell: Safety and Caution

The pyrotechnic hazard had already been identified during the preparatory phase, and specialized experts were constantly integrated into the earthwork teams. This was a precautionary measure that can only be welcomed, as in March 2024 it led to the discovery of a suspicious explosive device and the immediate activation of the safety protocol: suspension of construction, evacuation, and securing of the site. The presence of a 250-kg shell was quickly confirmed. A coordination center was activated in collaboration with the prefecture, law enforcement, and bomb disposal teams. The explosive device was placed in a secure temporary storage facility until its recovery. No incidents, no injuries.

Circular economy at the heart of the operation

The construction site fully implemented the principles of the circular economy in the processing of the 175,000 m³ of excavated material:

• 40% of the materials were recycled after screening and crushing and reused directly on site
• 60% of the excavated soil was processed at a bio-center and subsequently recycled

The Construction Site in Numbers

A Transformed Area

Upon completion of this construction project, 11 hectares of the municipality’s industrial brownfields will be restored to a condition suitable for new uses. This project demonstrates Séché Environnement’s ability to carry out complex remediation projects under challenging conditions and with high standards for safety, environmental performance, and consideration for the surrounding community.