Applicability of different woody plant species to vertical flow constructed wetland.

Abstract

The plant species used in constructed wetlands are mainly aquatic herbaceous, most of which tend to die during winter in subtropical areas. At present, very few studies have examined the performance of woody plants in constructed wetlands. In order to increase plant diversity and improve purification ability of vertical-flow constructed wetland during winter, 10 woody plant species were tested by establishing the microcosms simulating vertical-flow constructed wetlands. Their applicability was integrally evaluated, on basis of their adaptability, rhizospheric enzyme activity, and rhizospheric microbial diversity. The results showed that (1) seven woody plant species, Adina rubella, Salix rosthornii, Callicarpa dichotoma, Nerium oleander, Hibiscus mutabilis, Ligustrum obtusifolium, and Ligustrum lucidum could survive in the simulated vertical-flow constructed wetland; (2) N. oleander and C. dichotoma had higher nitrogen (N) and phosphorous (P) absorption capacity; (3) according to the integral evaluation, N. oleander, C. dichotoma, and S. rosthornii have excellent applicability for vertical-flow constructed wetland; A. rubella and H. mutabilis have moderate applicability; L. obtusifolium and L. lucidum have poor applicability; Ligustrum. japonicum "Howardii", Pittosporum. tobira and Distylium. buxifolium, were not applicable to vertical-flow constructed wetland. N. oleander, C. dichotoma, and S. rosthornii are recommended for application in vertical-flow constructed wetland.