Removal of Nitrogen and Phosphorus from Black-Odor Water by Different Submerged Plants

Abstract

In general, nitrogen and phosphorus in eutrophic water are absorbed by submerged plants for growth, which is considered as a feature and frequently applied in sustainable wastewater treatment. These plants are entirely submerged at the bottom of the water, absorbing nitrogen and phosphorus by roots, stems, leaves and epidermal cells. Compared with other species of aquatic plants, submerged plants show certain advantages in the aspects of planting area, total biomass and total removal of nitrogen and phosphorus. Rational utilization of submerged plants is an effective way to remove nitrogen and phosphorus from eutrophic water. Submerged macrophyte has been at the focus of attention in recent years as an alternative system for aquatic plant wastewater treatment with several applications in eutrophication. Aiming at the pollution control scheme of inland lakes, in this study, the removal of nitrogen and phosphorus by Hydrilla verticillaya (H. verticillaya) and Vallisneria natans (V. natans) were studied and compared in monoculture and mixed-culture plantings, thus screened the best submerged plants. Results showed that the removal capacity for ammonium (NH+4–N), Nitrate (NO–3–N) and total phosphorus (TP) from high to low was NH+4–N, NO–3–N, and TP. Reasonable allocation of plants can improve the removal efficiency of nitrogen and phosphorus. The order of removal capacity for different submerged plants to pollutants was: mixed culture V. natans and H. verticillaya > H. verticillaya > V. natans. The transformation of NO–3–N to NH+4–N was considered as the NH+4–N removal mechanism.