Wastewater Treatment through Ornamental Plants: A Review

This review deals with two untreated wastewater types, including domestic wastewater (in tourist destinations) and pharmaceutical industry wastewater, to shed light on the efficiency of constructed wetlands (CW). In mountainous areas, it has always been difficult to have a proper sewage treatment and disposal system for which a proper method is proposed in this paper. In CW, toxic materials should be removed from the water for which a surface CW layer is constructed. Ornamental plants (Canna flaccida, Zantedeschia aethiopica,and Canna indica)were used inthis study and they showed usefulness in reducing 80% of BOD (biological oxygen demand) and COD (chemical oxygen demand). Carbamazepine is a pharmaceutical drug that is widely used and pollutes aquatic environments when it is discharged untreated. This problem can be solved by constructing a horizontal subsurface flow wetland in which the vertical subsurface flow in the wetland is considered and the wastewater is then stabilized in ponds. Three different ornamental species were used (Thypha latifolia, Iris sibirica,and Zantedeschia aethiopica) and their performance was explored on parameters like dissolved oxygen, pH, oxidation/redox potential (Eh) whose average mass removal was 62.5 ± 4.5% and 59.0 ± 4.5%, respectively. The results showed the amazing performance of the two former species. The ornamentals used to get the flowers for commercial production included Zantedeschia aethiopica, Strelitzia reginae, Anthurium andraeanum and Agapanthus africanus. After the system was supplied with the target wastewater, Zantedeschia aethiopica grew about 60 flowers and maintained a healthy outlook while other species grew large leaves, and some died due to the harsh environmental conditions. The reviewed data depicts that Canna indica gave great results for the BOD and COD removal with Z. aethiopica having the potential of giving a greater number of flowers while tolerating the weather conditions. However, for carbamazepine, two species that could take up the pollutants were found to be Iris sibirica and Zantedeschia aethiopica.