Abstract
This study assesses the treatment of palm oil mill (PaM) final discharge wastewater using a cost effective technology approach of phytoremediation. paM final discharge wastewater obtained from final distribution pond at KL Kepong Berhad Palm Oil Mill, Tanjong Malim was treated with three species of local macrophytes, Leersia oryoides, Pistia stratiotes and Ludwigia peploides. The phytoremediation performance was evaluated by monitoring the changes and removal efficiency (%) of BOD5, COD, N-NH3, TSS and pH level. The characteristics of nutrient uptake were determined by measuring the percentage of C, H and N elements, bioconcentration factor (BCF) and translocation factor (TF) of Ca, Mg, K, Na, Fe and Zn in leaf, stem and root organs of the macrophytes. The microbial population in the rhizosphere was identified using partial 16S rRNA molecular technique. It was found that BOD5, COD, N-NH3 removal efficiencies of 93%, 30%, and 82% were achieved for Pistia stratiotes, 90%, 27% and 80% for Leersia oryzoides and 93%, 20% and 80% for Ludwigia peploides, respectively after 15 days of treatment. The N percentages were increased in all studied macrophytes leaves. The BCF values for Fe and Zn were found highest in Ludwigia peploides than other elements, 1.47 x 104 Llkg and 1.18 x 104 Llkg, respectively. Low TF values «1.0) obtained for Fe and Zn indicated that most of them were retained in root for phytostabilization. In this study, Bacillus megaterium, Pseudomonas aeroginosa and Bacillus cereus that usually involved in denitrification process was identified in Pistia stratiotes, Ludwigia pepoides and Leersia oryzoides roots, respectively which confirmed the macrophytes-microorganisms interaction in the phytoremediation. These results suggest that phytoremediation of paM final discharge wastewater was feasible with Ludwigia peploides as the most tolerance macrophytes. The finding is of prominence important for improvement of the existing palm oil mill effluent (POME) treatment system.