Evaluation of Eichhornia crassipes, Pistia stratiotes and Vetiver zizanoides in Phytoremediation of a Hospital Wastewater Effluent

Abstract

The study assessed the physicochemical parameters from a hospital wastewater treatment plant in Zaria, using a standard method for water and wastewater examination and its phytoremediation by hydroponic treatment method using Eichhornia crassipes (water hyacinth), Pistia stratiotes (Water lettuce) and Vetiveria zizanoides (Vetiver grass). Results recorded were analyzed by one-way Analysis Of Variance at 95% confidence, multiple comparison tests, and quantitative linear relationship. The study showed higher concentrations of Electrical Conductivity (EC) (951.83 µs/cm), Phosphate (PO₄) (64.46 mg/l), Biological Oxygen Demand (BOD) (244.90 mg/l), Chemical Oxygen Demand (COD) (625.50 mg/l), Total Suspended Solid (TSS) (27.30 mg/l), Potassium (K) (40.67mg/l) above the permissible limit standard by WHO and FAO, Phytoremediation showed there was significant difference at P ≤ 0.05 in reduction capacity across treatment between water hyacinth, water lettuce and vetiver grass for EC (49.8, 41.6 and 51.4%), TDS (51.3, 47.0 and 63.0%), PO₄ (49.0, 45.3 and 53.0%), COD (47.3, 48.4 and 57.1%), NO₃ (51.6, 43.1 and 64.6%), TSS (49.5, 42.7 and 60.3%), NH₃ (44.7, 40.8 and 53.2%), SO4 (53.9, 47.2 and 62.8%). Plant analysis results showed higher concentrations of contaminant in the roots of water hyacinth than in the shoot, higher in the shoot of vetiver grass than its roots, and an even distribution in roots and shoots of water lettuce. Therefore, the three plants can be used effectively in the phytoremediation of wastewater contaminants due to cost-effectiveness, eco-friendliness, and the emerging cheaper technology for a lasting solution to the problems of water contamination to both humans and the environment.