Evaluation for Removal Efficiencies of Aqueous Pollutants from the Industrial Wastewater By the Duckweed, Spirodela Polyrhiza.

Recently, phytoremediation, an economical and eco-friendly method to remove pollutants from the environment using plants, is under the spotlight. This study was conducted to evaluate the removal capacity of the heavy metals Cd and Cu as well as the nutrients N and P from the synthetic wastewater by using Spirodela polyrhiza. Additionally, it was performed to compare the removal efficiencies of pollutants in single, binary, quaternary mixtures by Spirodela polyrhiza. As N, P, Cd and Cu had been singly added to the synthetic wastewater with the Spirodela polyrhiza, their concentrations were decreased over time. Their removal efficiencies followed the order: P > Cu > N > Cd. In treatment of binary mixture of N + P, the removal efficiencies of N and P were 71% and 91%, respectively. In the treatment of binary mixture of Cd + Cu, those of Cd and Cu were 49% and 77%, respectively. In the treatment of quaternary mixture of N+ P+ Cd + Cu, the removal efficiencies of N, P, Cd, and Cu were 46%, 62%, 24%, and 42%, respectively. The removal efficiencies of pollutants were higher in binary mixture treatments than in quaternary mixture treatments. As a result of analysis of Spirodela polyrhiza, more pollutants were found to be included inside the plant treated with the binary mixture than with the single materials. The inhibitory effect on the activity of Spirodela polyrhiza was considered to be decreased by antagonistic effect of N and P as well as Cd and Cu. Based on the results obtained from this study, it appears that Spirodela polyrhiza can be potentially used for the removal of the N, P, Cd and Cu from the industrial wastewater. The further research is extensively needed to elucidate the mechanisms involved in the removal of the pollutants by Spirodela polyrhiza from the industrial wastewater.