Authorized to discharge polluted waters in the Calanques National Park, the Alteo de Gardanne alumina plant (Bouches-du-Rhône) intends to reduce its aluminum and arsenic discharges below the legal threshold by 2019 required, thanks to a C02 technology unveiled Thursday in Marseille
Alteo, the world leader in specialty aluminas, ceased discharging "red mud", solid waste resulting from the transformation of bauxite, at sea. In fifty years, Alteo had dumped more than 20 million tons of this "sludge" into the Cassidaigne pit, off Cassis, including arsenic, cadmium or mercury.
A prefectural decree of December 28, 2015, however, authorized Alteo to continue for six years its liquid discharges at sea, in the heart of the Parc national des calanques. With the obligation to pass by the end of 2021 under the maximum permitted thresholds for the six elements for which it is still in excess, including aluminum and arsenic.
Regarding the pH of its effluents or their content in these two metals, Alteo hopes to be in good standing with more than two years in advance, thanks to a new process of water treatment by CO2 injection. The reprocessing plant, an investment of 6 million euros to be launched in April, should be operational in the first half of 2019, assured Frédéric Ramé, president of Alteo, Thursday at a press conference.
its 270 cubic meters hour of current liquid effluents, Alteo rejects 131 mg of aluminum and 0.06 mg of arsenic per liter, for maximum thresholds of respectively 5 and 0.05 mg per liter.
– 440 tonnes d'aluminum –
Regarding iron, one of the six parameters on which Alteo was still exempted at the end of 2015, the company has already gone to a threshold one hundred times lower than the limit, at 0.02 mg per M. Ramé,
The last two elements on which Alteo still has to make progress are the biological and chemical oxygen demand levels of its liquid discharges, two indicators of the polluting load of wastewater. "In particular, we are working on nano-filtration and osmosis techniques," said Eric Duchenne, Alteo's director of operations.
99% reduction in the metal content of marine discharges thanks to filter presses at work since 2015, with the elimination of red mud now stored on land, another 68% drop in metals in liquid effluents in 2016 and 2017: welcoming these results, Frédéric Ramé again pleaded Thursday to "go out the sterile debate between industry and environment. "
This wish was swept away by Henry Augier, president of the Union Calanques Littoral association, according to which the only solution is" the total cessation of Alteo's rejections ". "The National Park of creeks, created in 2012, is still the only park in the world discredited by industrial pollution," accused the former director of the laboratory of marine biology of the University of Marseille-Luminy, figures to the support, with the AFP.
In one year, according to the statistics of April 2017 of its association, it is about 440 tons of aluminum or 128 kg of arsenic, among others, which escape towards the Mediterranean.