Physicochemical Characterization of Palm Mill Oil Effluent and Bioremediation of Impacted Soil

Abstract

Palm oil mill effluent (POME) is a waste product from palm oil production which is known to have adverse environmental effect when disposed untreated. The aim of this study was investigate the bioremediation potentials of indigenous bacteria and fungi of POME on impacted soil. Collection of samples, physicochemical characterization of POME and soil samples, microbiological analysis of the POME and lipase assay were all carried out using standard techniques. Replicate readings were then subjected to analysis of variance (ANOVA). A total of 7x4 (28) experiments designated A to G were set up. Three experiments from each block received 100 ml, 200 ml and 300 ml of POME while the fourth had no POME. The treatments were as follows: block A (soil only), B (soil +effluent), C(soil +effluent + fungi), D(soil +effluent+ bacteria), E(soil +effluent + bacteria and fungi), F( soil +effluent + chicken droppings) and G (soil +effluent + bacteria, fungi and chicken droppings). After 14 days, water leaf (Talinum triangulare) were planted in all the set ups. Results of the physicochemical analysis of the POME and soil samples showed that addition of POME brought about significant (p < 0.05) changes in these parameters. A total of seven isolates were recovered from the effluent out of which Bacillus species and Aspergillus niger showed the highest lipase activity and were used for the bioremediation. Despite receiving about 300 ml of raw effluent, set ups (F and G), showed the best growth even much better than the A that had no effluent in them. Analysis of variance of the replicate readings of the plant heights showed significance (p < 0.05). However, the lengths and widths of the leaves of F and G performed better than the rest. The findings suggest that palm oil mill effluent impacted soil could be reclaimed using a consortium of indigenous microorganisms and biostimulation.