Optimization of kinetics and operating parameters for the bioleaching of heavy metals from sewage sludge, using co-inoculation of two Acidithiobacillus species.
Water Sci Technol
; 2017(2): 390-403, 2018 May.
Article
en En
| MEDLINE
| ID: mdl-29851391
ABSTRACT
This study explores the potential for synchronous extraction of Cu, Cr, Ni and Zn during sewage sludge bioleaching processes, using three types of bacterial cultures a pure culture of Acidithiobacillus ferrooxidans (A. ferrooxidans); a pure culture of Acidithiobacillus thiooxidans (A. thiooxidans); and a mixed culture of A. ferrooxidans and A. thiooxidans. Variable operating parameters included initial pH, solids concentration, sulfur concentration and ferrous iron concentration, with optimization via Box-Behnken design of response surface methodology. Results indicate that the mixed culture of A. ferrooxidans and A. thiooxidans, was the most effective at bioleaching heavy metals from sewage sludge. The optimal operating conditions were as follows an initial pH of 2.0, with concentrations of 3% solids, 6.14 g L-1 sulfur and 4.55 g L-1 ferrous iron. Maximum extraction efficiencies obtained after 14 days of bioleaching under optimal conditions, were 98.54% Cu, 57.99% Cr, 60.06% Ni and 95.60% Zn. Bioleaching kinetics were effectively simulated using a shrinking core model to explain the leaching reaction, with modelling results suggesting that the rate was determined by the diffusion step.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Aguas del Alcantarillado
/
Contaminantes del Agua
/
Eliminación de Residuos Líquidos
/
Metales Pesados
/
Acidithiobacillus
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Water Sci Technol
Asunto de la revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Año:
2018
Tipo del documento:
Article