ABSTRACT
Bioremediation of tannery effluent has been regarded as a cheaper, more efficient method of removing toxic elements from the environment and ensuring the recycling of resources that would have been discarded after other remediation processes. Indigenous bacteria and fungi from effluent were isolated, characterized and identified using standard microbiological procedure. Isolated bacteria and fungi were screened for degradative ability using chemical oxygen demand and turbidity as screening parameters. Tannery effluent samples used in remediation included samples inoculated with microorganisms, samples inoculated with microorganisms and supplemented with mineral salt medium (MSM) and control. Treatment of tannery effluent was carried out for 30 days with samples drawn every 5 days for analysis of microbial growth, pH, total dissolved solids, total suspended solids, total solids, dissolved oxygen, chemical oxygen demand, phenol and biological oxygen demand. Indigenous isolates from tannery effluent were identified as E. coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Aspergillus niger, Fusarium sp., Trichoderma sp., Penicillium sp. and Alternaria sp. These organisms were inoculated singly, screened, after which Staphylococcus aureus, Pseudomonas aeruginosa., Bacillus cereus and Penicillium sp. were selected. Penicillium sp. was the most effective organism in remediation studies responsible for the highest increase in pH (1.66%), highest reduction in BOD (16.98%) and total solids (61.04%), Staphylococcus aureus resulted in highest reduction of total dissolved solids (32.80%), phenol (26.69%) and Pseudomonas aeruginosa reduced COD (31.47%), TSS (53.62%) and DO (50.44%). Supplementation of tannery effluent with MSM was found to increase remediation capacity of Penicillium sp., Bacillus cereus, Pseudomonas aeruginosa and Staphylococcus aureus. The results showed that indigenous microorganisms in tannery effluent are capable of degrading effluent and supplementation with specialized medium improved bioremediation. More research is needed to understand and develop more efficient bioremediation process for industrial effluent.
