Dépôt numérique

Bacterial leaching of toxic metals from municipal sludge : influence of sludge characteristics.

Tyagi, Rajeshwar Dayal, Blais, Jean-François ORCID: https://orcid.org/0000-0003-3087-4318, Auclair, Jean-Christian et Meunier, Nathalie (1993). Bacterial leaching of toxic metals from municipal sludge : influence of sludge characteristics. Water Environment Research , vol. 65 , nº 3. p. 196-204.

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The presence of high concentrations of heavy metals in wastewater sludge is one of the most important factors that limit the application of sludge on agricultural land. ln the last few years, the mi­crobiological process of heavy metals removal from wastewater sludge has been studied in a batch mode. In the present study, the effects of metals, solids concentration, and initial pH on indigenous sulfur-oxidizing thiobacilli growth and metal solubilization were examined. The results obtained indicate that metals removal is possible even in high sludge solids concentration (70 g/L). The rate of sulfuric acid production through the oxidation of added elemental sulfur is increased by the in­creased sludge solids concentration. The initial pH of the sludge (7.0- 3.0) does not affect the capacity of metal Ieaching. The high concentration of metallic ions (Cu2+ and Zn2+) adjusted in the sludge did not greatly affect the microbiological activity ofmetal-leaching bacteria. The leaching tests conducted with metal sulfides as substrate (chalcocite, galena, pyrite, sphalerite) showed that metals solubilization from sulfides occurred by an indirect mechanism ( production of acid followed by metal solubili­zation due to the action of the acid produced). No evidence of direct oxidation of metal sulfides was observed.

Type de document: Article
Mots-clés libres: bioleaching; elemental sulfur; heavy metals; wastewater sludge; thiobacilli
Centre: Centre Eau Terre Environnement
Date de dépôt: 17 févr. 2021 16:40
Dernière modification: 18 févr. 2022 19:14
URI: https://espace.inrs.ca/id/eprint/11240

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