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Performance of Semi-passive Systems for the Biological Treatment of High-As Acid Mine Drainage: Results from a Year of Monitoring at the Carnoulès Mine (Southern France)
Performance of Semi-passive Systems for the Biological Treatment of High-As Acid Mine Drainage: Results from a Year of Monitoring at the Carnoulès Mine (Southern France)
Abstract : Two semi-passive treatment systems for iron (Fe) and arsenic (As) removal in AMD were installed and monitored in-situ for
more than a year. These technologies were designed to treat the As-enriched AMD (≈ 1 g/L Fe(II) and 100 mg/L As(III)) of
the ancient Carnoulès mine. The treatment was based on biological Fe and As oxidation by indigenous bacteria, and subse-
quent immobilization of As by ferric hydroxysulfates. Forced aeration and wood/pozzolana or plastic support were used for
biofilm attachment. The system performance ranged from 86 to 98% for Fe oxidation, 30 to 60% for Fe removal, and 50 to
80% for As removal at a hydraulic retention time of 9 h. No significant difference were measured between the two biofilm
supports. The wood/pozzolana support had a shorter delay for performance recovery after interruptions. Iron oxidation rates
were similar to those obtained in the Carnoulès AMD stream and laboratory bioreactor, while As oxidation seemed to be
enhanced. The sludge accumulated between 39 and 91 mg/g of As, mainly in the As(V) oxidation state; jarosite and amor-
phous ferric hydroxysulfate phases were the main Fe and As scavengers. Challenging environmental conditions during the
long monitoring period confirm the robustness of the treatment units. The data will be useful in designing future full-scale
treatment systems adapted to As-rich AMD.
https://hal.mines-ales.fr/hal-03717097
Contributeur : Administrateur IMT - Mines Alès Connectez-vous pour contacter le contributeur
Soumis le : vendredi 29 juillet 2022 - 12:59:57
Dernière modification le : samedi 22 octobre 2022 - 05:37:13
Contributeur : Administrateur IMT - Mines Alès Connectez-vous pour contacter le contributeur
Soumis le : vendredi 29 juillet 2022 - 12:59:57
Dernière modification le : samedi 22 octobre 2022 - 05:37:13