Studies on Removal of Heavy Metals from Tannery Effluent by Native Isolates of Bacteria and Fungi

Aim: This research work is aimed at studies on removal of heavy metals from tannery effluent by species of bacteria and fungi.

Study Design: This study is designed to isolate and identify bacteria and fungi from tannery effluents, to determine the concentration of heavy metal in tannery effluent, to assess the removal of heavy metals by bacteria and fungi from tannery effluents, to assess the effect of temperature and pH on heavy metal removal.

Place and Duration of Study: Department of Microbiology, Nasarawa State University Keffi, Nasarawa State, Nigeria, between January 2017 and December 2017.

Methodology: A total of four (4) tannery effluents samples were obtained from Challawa industrial area in Kano, Nigeria. Bacteria and fungi were isolated from the effluent and identified using standard microbiological methods. The heavy metal content of the effluent was determined using Atomic Absorption Spectrometer. The heavy metal removal capacity by bacteria and fungi was also determined at different temperatures and pH.

Results: The bacteria isolated from the effluent were Bacillus subtilis and Pseudomonas aeruginosa and the fungal isolates were Penicillium notatum and Aspergillus niger. The identified heavy metals were Chromium, Cadmium, Copper, Lead, Zinc and Iron. The bacterial and fungal load of the tannery effluent were within the range of; bacteria (2.9-4.3×105 Cfu/L) and Fungi (5.0×10 4- 1.0 × 105. Cfu/L). Out of the samples of tannery effluent obtained, the occurrence of Pseudomonas aeruginosa, Bacillus subtilis, Penicillium notatum and Aspergillus niger were 100%. The result of the study revealed that the values for the metals were above the maximum permissible limits of both the Nigeria Standard of Drinking Water (NSDW) and World Health Organization (WHO). All isolated organisms showed an affinity for Pb, Cu, Cr and Zn.

Conclusion: From this study, it can be deduced that bacteria and fungi have a high capacity for removal of metal from tannery effluents. However, there is a need for further work to be done to validate and improve these findings.