Removal of nutrients from secondary-treated municipal wastewater in wetland microcosms using ornamental plant species

Abstract

Different wetland species may have a differential capacity to take up nutrients from wastewater in the process of tertiary water purification. Ten emergent plant species, including six ornamental species and four rush species were planted in the vertical-flow wetland microcosms and fed a simulated wastewater solution containing 17.5 mg N l−1 in the 1:1 proportion of NH4+-N and NO3&minus-N, and 10 mg P l−1 in the concentrations similar to the secondary-treated municipal wastewater. Significant differences in both aboveground and belowground biomass were found among plant species. Significant differences in the removal efficiencies of NH4-N, NOx-N and PO4-P were detected among different species, with Canna indica achieving the relatively high nutrient removal efficiency. Although biomass of Canna indica was not the highest among the ornamental species, it has shown vigorous and healthy growth, and a relatively high potential of rooting-zone aeration and nutrient removal efficiency in the wetland microcosms.