DOE OSTI2018
The former Lithium production facility located at Miramas in the South-East of France recently completed a 10-year program of process equipment removal, building demolition and soil remediation to recover mercury (Hg) that had been lost during operations at the site. After over 100 years ago chemical production, all production activities stopped in 2009, and immediately afterwards the clean-up project began. The main project focused on the demolition of all facilities and the decontamination of building materials and soil clean-up, with the goal of remediating the site for future industrial purposes. Prior to starting the decommissioning and clean-up work at the site a detailed site survey was conducted to identify the extent of the contamination of the site. After investigations into available technologies, the decision was made to install on-site treatment processes. This resulted in fewer residual environmental effects (trucking pollution, shipping containers, volume of materials, etc), a reduction in logistic complications, and, importantly, was cost effective compared to sending all untreated material to external processing facilities. This decision resulted in a need to optimize demolition waste management, while ensuring the highest clean-up and safety levels. A variety of treatment processes were investigated and compared and two technologies were finally selected and implemented. The first process was a 'thermal desorption unit (TDU),' which heated excavated soils and captured the vaporized mercury. The second was a washing process that was used to remove surface contamination. After the contaminated areas were excavated, materials were crushed, screened and sorted into different sizes, with each pile being routed to the appropriate process. The smaller-sized particles were treated in the TDU. A batch of around 12 MT was fed into a moisture evaporator and then into a mercury evaporator. The soils were then cooled, sampled to ensure no residual Hg contamination before being mixed with a binding agent, and returned to the excavation site. Larger materials with surface contamination were washed to remove the contamination. The liquid effluents were sent to a tank where the contaminated fines were removed, dried, pressed and sent for processing. If the washed, coarse materials failed to reach acceptable mercury levels, they were crushed again and sent to be treated in the TDU. The washing fluid was recycled for the next batch. (author)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗