Removal and recovery of heavy metals by bacteria isolated from activated sludge treating industrial effluents and municipal wastewater

Citation
Wc. Leung et al., Removal and recovery of heavy metals by bacteria isolated from activated sludge treating industrial effluents and municipal wastewater, WATER SCI T, 41(12), 2000, pp. 233-240
Citations number
10
Categorie Soggetti
Environment/Ecology
Journal title
WATER SCIENCE AND TECHNOLOGY
ISSN journal
02731223 → ACNP
Volume
41
Issue
12
Year of publication
2000
Pages
233 - 240
Database
ISI
SICI code
0273-1223(2000)41:12<233:RAROHM>2.0.ZU;2-9
Abstract
A total of nineteen metal-resistant and non-resistant bacteria from activat ed sludge treating both metal-contaminated industrial effluents and municip al wastewater were isolated and identified. These included both Gram-positi ve (e.g. Micrococcus) and Gram-negative (e.g. Pseudomonas) bacteria. The bi osorption capacity of these strains for five different heavy metals (copper , nickel, zinc, lead and chromium) was determined at pH 5 and initial metal concentration 100 mg/L. Pseudomonas pseudoalcaligenes and Micrococcus lute us were found to be capable of removing significant amounts of copper and l ead. Hence, they were selected for further investigations. Langmuir adsorpt ion isotherms adequately represented the distribution of copper and lead fo r both species. The study of pH effect on metal removal for both species in dicated that the metal biosorption increased with increasing pH from 2 to 6 . The effect of competing cations on biosorption of P. pseudoalcaligenes wa s studied. Sulphuric acid (0.05 M) was the most efficient desorption medium among the eleven reagents tested. Over 90% of copper sorbed on the cells o f M, luteus could be recovered by washing with 0.05 M sulphuric acid within five minutes. The biosorbent was used for at least five biosorption and de sorption cycles without loss of copper removal capacity. Immobilization of M. luteus in 2% calcium alginate and 10% polyacrylamide gel beads increased copper uptake by 61%.