Phosphorus activation from phosphorus-saturated substrates by constructed wetlands plants: Performance and mechanism

Abstract

One of the key challenges in operating constructed wetlands (CWs) is phosphorus-saturated substrates that markedly impacts their normal functioning and pollutant removal capabilities. This study aimed to investigate the potential of CW plants in activating phosphorus from phosphorus-saturated substrates under various treatments. Results showed that the inorganic phosphorus (IP) content in a substrate planted with Canna indica (M group) decreased by 48.73 % and 74.82 % after 90 (stage 1) and 150 days (stage 2), respectively. When nitrogen, biochar, and plant litter were added in the substrate, biomass and root growth significantly increased. At the end of stage 2, substrates in MYN (nitrogen addition groups) and MSW (plant litter addition groups) treatments had a significantly lower IP than that in the M treatment. Among the four bacteria isolated, Curtobacterium pusillum had the higher phosphate-solubilizing potential. Inoculation of the substrate with C. pusillum in the M group increased the relative abundance of Streptophyta, Burkholderia, Massilia, and Arthrobacter and residual phosphorus activation by 57.16 %. These results indicate a promising potential of CW plants in terms of phosphorus activation from phosphorus-saturated substrates, subsequently facilitating the sustainable development of CWs.