Simultaneous Removal of Nutrients and Heavy Metals from Wastewater using Sole and Combined Water Macrophytes: Eichhornia crassipes, Lemna minor, Nymphaea, and Pistia stratiotes

We investigated the individual and combined (CB) performances of four aquatic plant species, Eichhornia crassipes (water hyacinth, WH), Lemna minor (duckweed, DW), Nymphaea (water lily, WLY), and Pistia stratiotes (water lettuce, WL) in removing selected nutrients (PO43-, NO3–, NH3) and heavy metals (Cd, Cr, Cu, Pb, Zn) from well water for a 30-day duration while monitoring changes in the physicochemical properties (pH, salinity, conductivity, total dissolved solid TDS). WLY could not thrive beyond the 10th day, while other plants lasted the whole test period. All macrophytes leached PO43- into the water, showing negative removal efficiencies as follows: WH>CB>WL>WLY>DW. Likewise, WL, DW, and CB leached NO3– into the solution, whereas WH showed no observable difference between the initial and final concentrations, and WLY reduced the initial concentration (13.56 mg/L) by 87.5%. All plants recorded significant NH3 removal except WLY, which raised the concentration from 4.88 to 5.04 mg/L. Individual and combined macrophyte set-ups significantly removed Cr, Cu, Cd, Pb, and Zn. WL was most effective in removing Cr, Cu, and Zn, achieving removal efficiency of 86.8%, 84.56%, and 62.42%, respectively. Also, CB had the highest removal efficiency of 93.08% for Cd and 97.09% for Pb. In conclusion, understanding the nature of water contaminants and physiochemical properties is essential for selecting the appropriate macrophytes, solely or combined, for optimum growth and effective phytoremediation.