Soil remediation of the Seguin Island and Trapèze sites

Soil remediation of the Seguin Island and Trapèze sites

Challenge

The Renault factories, constructed in 1929 on the Seguin Island in Boulogne-Billancourt (92), stopped operating in 1992. As part of a real-estate redevelopment project on the island, Antea Group was commissioned by Renault for the site soil remediation (116.14 acres) and carried out the following tasks:

  • Comprehensive environmental studies, including detailed historical reviews on each lot;
  • Environmental investigations;
  • Human health risk assessments;
  • Technical specifications for remediation works;
  • Technical and financial supervision of the works;
  • Remediation completion reports;

Assistance in the communication between the project owner and the administration and the developer.

Solution

Antea Group defined an investigation strategy approved by the administration:

  • Soil borings till a depth of 8 m bgl and following a 10 m-wide grid;
  • Soil sampling on 2 m-thick layers;
  • Laboratory analytical program based on historical activities;
  • Groundwater investigations;
  • Soil gas investigations;
  • Definition of remediation targets following a health risk-based approach.

Antea Group also defined the works completion control protocols.

Results

The decontamination works involved:

  • 420,000 t of excavated soils,
  • 220,000 t of polluted soils treated on site,
  • 160,000 t of polluted disposed off site,
  • 800,000 t of soils managed.

 

The residual contamination left in place due to technical constraints amounted to 900 tons, which is less than 0.2 % of the identified contamination.

 

The closure certificates have been obtained from the administration for the 5 remediation orders.