Phosphorus removal from rural domestic wastewater and removal pathways analysis using reed wetlands

Subsurface horizontal-flow wetlands planted Phragmites australis was constructed to treat rural domestic wastewater.Phosphorus removal and plant uptake in constructed wetland from wastewater were interviewed.The results showed that phosphorus removal efficiency increased with hydraulic retention time(HRT) increase.Phosphorus removal rate was greater than 88% when HRT was more than 7 days.The wetland exhibited a strong linear relationship of TP loading in influent and removal in effluent(R2 0.91).Wetland plant was harvested in later November with an aboveground biomass of 1.65 kg.m-2.Plant uptake of TP was 3.68 g.m-2.a-1.Pathways of TP removal in constructed wetland were analyzed.Adsorption of substrate was main mechanism of TP removal in subsurface horizontal-flow wetland.Amount of plants uptake accounted for 9.1% of TP removed by wetland.However,the existence of macrophyte in constructed wetland plays important role on TP removal in wetland through influencing indirectly other TP removal mechanisms.The experiment shows that constructed wetland is a prospective strategy for treating rural domestic wastewater.