Phytoremediation of elements in municipal wastewater treatment plant effluent by Lemna gibba L.: a full-scale study

In this study, capacity of naturally growing Lemna gibba L. in removing elements (B, As, Al, Ca, Ba, Co, Fe, Cu, K, Cr, Li, Mo, Ni, Mn, Na, Mg, Sb, P, Si, Pb, Se, Ti, Zn, V, and Sr) from the effluent of secondary clarifier of a municipal wastewater treatment plant (MWWTP) was determined week by week (W1, W2, W3, and W4) and analyzed as a whole using statistical models. To determine the removal contribution of Lemna gibba L. to the MWWTP effluent, secondary clarifier without Lemna gibba L. was used as a control. The aim here is to determine the contribution of Lemna gibba L. to MWWTP’s removal efficiency. Trace elemental quantification was conducted via validated ICP-MS following microwave-assisted acid digestion. In this context, according to the analysis results, the removal efficiency of Lemna gibba L. for Al was highest at 89.66% over the weeks. Furthermore, treatment efficiencies above 50% were achieved for Co (57.86–60.61%), Sb (64.25–67.35%), and Ti (63.27–66.21%). Based on statistical analyses, PCA (principal component analysis)) and HCA (hierarchical cluster analysis) models explained 85% of the total variance. As a result, this study demonstrated that Lemna gibba L. removes elements from MWWTP effluent, contributing to the removal efficiency of the secondary clarifier and clearly showing its potential use in phytoremediation.