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

Water contamination poses negative impacts on humans and the ecosystems leading to issues of water scarcity, water stress, drought and mortality related to water diseases and hence the need for wastewater recycling for future reuse. The study assessed the physicochemical parameters from a hospital wastewater treatment plant in Zaria, Kaduna using standard method for water and wastewater examination and its phytoremediation by hydroponic treatment method using Eichhornia crassipes (waterhyacinth), Pistia stratiotes (Waterlettuce) 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 waterhyacinth, waterlettuce 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 result showed higher concentration of contaminant in the roots of waterhyacinth than in the shoot, higher concentration in the shoot of vetiver grass than its roots and there was even distribution in roots and shoots of water lettuce. Therefore, the three plants can be used effectively in phytoremediation of wastewater contaminants due to cost effectiveness, ecofriendliness as emerging cheaper technology for a lasting solution to the problems of water contamination to both humans and the environment at large. Key words: Wastewater, Contamination, Phytoremediation, Vetiver grass, Waterhyacinth, Waterlettuce