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

W. C. Leung, M. F. Wong, H. Chua, Wai Hung Lo, P. H. Yu, C. K. Leung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

167 Citations (Scopus)


A total of nineteen metal-resistant and non-resistant bacteria from activated sludge treating both metal-contaminated industrial effluents and municipal wastewater were isolated and identified. These included both Gram-positive (e.g. Micrococcus) and Gram-negative (e.g. Pseudomonas) bacteria. The biosorption 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 luteus were found to be capable of removing significant amounts of copper and lead. Hence, they were selected for further investigations. Langmuir adsorption isotherms adequately represented the distribution of copper and lead for both species. The study of pH effect on metal removal for both species indicated that the metal biosorption increased with increasing pH from 2 to 6. The effect of competing cations on biosorption of P. pseuodoalcaligenes was 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 of 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 desorption 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%.
Original languageEnglish
Pages (from-to)233-240
Number of pages8
JournalWater Science and Technology
Issue number12
Publication statusPublished - 30 Aug 2000


  • Adsorption
  • Bioremediation
  • Biosorption
  • Desorption
  • Heavy metals
  • Wastewater treatment

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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