Study on purification efficiency of vertical flow wetlands on domestic wastewater.

The combination method of intermittent influent and vertical flow wetlands (VFW) was used in the test to treat the domestic wastewater. Four artificial wetlands including Typha latifolia wetland,Phragmites australis (P.H.) wetland,polyculture wetlands (Typha latifolia and Phragmites australis) and non-vegetation wetland were established in the test. The effects of hydraulic retention time (HRT) and plant species on pollutants removal efficiencies were studied. The results showed that when HRT=7,the treatment efficiencies of wetlands with plants for the removal of TN and NH+4-N were up to 99.65% and 99.58%,respectively. For the control wetland,TN removal efficiency was up to 87.9% when HRT were 6 days,and NH+4-N removal efficiency was up to 91.8% when HRT were 5 days. TP removal efficiencies of four wetlands were higher than 93% when HRT was 6 days. Through the studies on different plants,it was found that vegetation wetlands had better nitrogen removal efficiency than non-vegetation wetland. The treatment efficacy of Phragmites australis wetland and polyculture wetland was better than Typha latifolia wetland.