Consultation on the Seveso high threshold plant project stalls due to lack of finalized studies

CIt was supposed to be a thematic forum on water management and flood risk related to the Electro Mobility Materials Europe (EMME) project near the port of Grattequina (Parempuyre-Blanquefort). On Wednesday, September 18, we were treated to a classic public meeting instead, with questions in all directions and answers that were not always precise, causing irritation among the assembly.

What is it? An industrial unit for converting nickel and cobalt in a flood zone on the banks of the Garonne. The principle: “We receive raw materials that have undergone initial purification, and we transform them via processes into nickel sulfate and cobalt sulfate. These products are solid, in the form of salts,” summarizes Henri Biscarrat, France project manager for EMME. They are used at the end of the chain to manufacture batteries in the gigafactories of northern France. What can we take away from the two and a half hours of discussions? Excerpts.

1 Embankments but where?

EMME initially planned to build a 28-hectare embankment. The copy has been revised. The raised area that will serve as a platform for the plant has been reduced to 14 hectares. In particular, to avoid penalizing the right bank in the event of flooding, as well as the port of Lagrange in Parempuyre.

The required volume nevertheless reaches 500,000 m³ of materials. Where will they come from? We don’t know. Not yet. Local suppliers have been surveyed. Will they be transported by road or by waterway? Again, nothing is certain, even if EMME wants to favor the maritime option. Astonishment among the public one month before the submission of the building permit application.

2 No pumping in the Garonne

To operate, the plant will need a water supply of 100 m³ per hour. The option of pumping from the Garonne initially planned has been abandoned. The supply will be done by recovering part of the wastewater from the Blanquefort treatment plant. The advantage is twofold, according to expert Hélène Bahurlet (Artelia company): “We preserve the natural resource and we recover part of the urban wastewater.”

As for discharges into the river, they will logically reach 40 m³/h with a temperature lower than or equal to 30 °C. EMME excludes a risk of warming of the environment. “The 40 m³/hour of effluents will represent 0.002% of the average flow of the Garonne. It is a bottle of water in a large volume”, estimates Hélène Bahurlet, assuring that this water will be filtered beforehand.

3 Modeling a disaster scenario

Since the land is located in a flood zone, hydraulic modeling was done to simulate the flow of water in the area. Several disaster scenarios were studied. The most recent is based on the Martin storm of 1999 combined with a rise in sea levels of 1.20 m. That is, the most pessimistic forecasts of the Intergovernmental Panel on Climate Change (IPCC) for 2150. The modeling takes into account the tide, winds, etc. According to the projected maps, these extreme conditions would not have an impact on the Seveso high threshold classified plant and its storage areas. Because the unit would be more than 6 meters high due to the backfilled area topped with a concrete slab. Like a castle on an island. In addition, the products will not be stored in bulk but in watertight big bags of 2 tons maximum enclosed in containers. What if a bag accidentally tears on the platform on a rainy day? “The contaminated water will in theory be isolated in a retention basin before following a liquid waste channel by physicochemical treatment.” Are there any sites of this type in Gironde? Big silence in the room. Next question…

4 Pollution cases in Finland

Florence Bougault, from the Society for the Study, Protection and Development of Nature in the South-West (Sepanso) Gironde, called on Érik Loot, appointed guarantor of the consultation, to ensure that flood risk studies are provided in detail, including the hypotheses taken into account. “We don’t just want a PowerPoint with four slides,” she said. Before reporting on an accidental spill of nickel sulphate in Finland ten years ago, during a maintenance operation in a factory. “It took three days for the authorities to detect the problem. In total, 66,000 kilos of nickel sulphate were discharged into a river. The pollution spread over 35 kilometres. It took months before it was resolved.” EMME assures that each installation in the process will benefit from specific retention. At the end of the meeting, the Alerte Seveso Bordeaux Métropole collective invited the public on October 27 at 2 p.m. to the Vallier estate (Parempuyre) to present its analyses.