Pennisetum sinese Roxb and Pennisetum purpureum Schum. as vertical-flow constructed wetland vegetation for removal of N and P from domestic sewage

In this study, two bioenergy plants, namely the Pennisetum sinese Roxb and Pennisetum purpureum Schum., were selected as wetland vegetation to remove nitrogen (N) and phosphorous (P) in vertical-flow constructed wetland (CW) systems. The total net nutrient accumulation by CW plants was 104 g N/m2 and 7.6 g P/m2 for Pennisetum sinese Roxb, 144 g N/m2 and 8.71 g P/m2 for Pennisetum purpureum Schum. Three CW systems (System A planting with Pennisetum sinese Roxb, System B planting with Pennisetum purpureum Schum., and System C without planting) were designed to evaluate total nitrogen (TN) and total phosphorus (TP) removal efficiency from wastewater. Results showed that the removal efficiency of TP from both System A and System B were significantly higher than that of System C, but there are no significant differences of the removal of TN among the three CW systems. After a five-month CW operation, System C was clogged and the TP removal efficiency was negative due to desorption of TP from the substrate. Our study demonstrated that the two newly selected plant species had a positive effect on removing TN and TP from wastewater and reducing clogging in the CW systems.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide