Bioremoval of Heavy Metals from Effluent of Port Harcourt Refinery UsingPluerotus ostreatus

Abstract

The presence of heavy metals in refinery effluent has the potential to pose significant risks to human health and the environment. However, the conventional heavy metal removal has limitations hence the need to introduce alternative treatments. Recently, there have been considerable interests in bio-adsorption of heavy metal using fungus. In the present study, the effectiveness of iron, zinc, lead, nickel, cadmium and chromium removal from refinery effluent was evaluated using living white rot fungus (spawn) viz., Pleurotus ostreatus. The fungus was amended with sawdust and rice bran. Physiochemical analysis of the effluent on day zero indicated the presence of Iron (0.775 mg/L), Zinc (0.750 mg/L), Lead (0.031 mg/L), Nickel (0.188 mg/L), Chromium (0.025 mg/L) and Cadmium (0.054 mg/L). P. ostreatus bioremoved the metals under study at pH 7.6, Temperature at 26.8°C and contact time 60 days with substrate (sawdust mixed with rice bran). Throughout the research, the percentage of removal was found to increase with increasing contact time. The heavy metals were determined using an atomic absorption spectrophotometer. Sawdust mixed with rice bran colonized with P. ostreatus spawn could be utilized as an excellent biosorbent thus exhibiting efficiency for Iron 80%, Zinc 99%, Lead 94%, Nickel 99%. Chromium 93%, and Cadmium 96% respectively. The analysis of variance of the five variables: lead, iron, nickel, cadmium and chromium showed that there was no significant difference at P<0.05 with the exception of iron. It was observed that P. ostreatus is efficient in bioremoving heavy metals as the levels of remaining heavy metals in the refinery effluent were below the limit of detection (<0.001 mg/L). This validates P. ostreatus as a potential bio-sorbent and can be employed in treatment of environments polluted with effluent containing high levels of lead, zinc, iron, nickel, cadmium and chromium.