This study evaluated the capability of a constructed wetland for treating saline wastewater. A pilot-scale constructed wetland system was set up and was initially operated at low, then increasing salt levels to determ...This study evaluated the capability of a constructed wetland for treating saline wastewater. A pilot-scale constructed wetland system was set up and was initially operated at low, then increasing salt levels to determine the effect of salinity on the contaminants＇ removal performance. The effect of hydraulic retention time （HRT） variation on treatment efficiency of the reed wetland was also discussed. Average removal efficiencies of the reed （Phragmites australis） wetland were found to be 79.0% for COD, 72.2% for ammonia nitrogen （NH3-N） and 82.8% for total phosphorus （TP）. Reed planting had obvious improvement on COD and NH3-N removal efficiency when compared to an unplanted system. With the seawater proportion in the influent increasing from 20% to 30%, the TP removal efficiency improved obviously. COD removal efficiency of the reed wetland was positively correlated with HRT under high salinity condition, while excess HRT had adverse impacts on the NH3-N and TP removal. Optimal HRT for NH3-N and TP removal was 4 days. Results obtained can be beneficially used to improve the use of constructed wetlands in saline wastewater treatment.展开更多
文摘This study evaluated the capability of a constructed wetland for treating saline wastewater. A pilot-scale constructed wetland system was set up and was initially operated at low, then increasing salt levels to determine the effect of salinity on the contaminants＇ removal performance. The effect of hydraulic retention time （HRT） variation on treatment efficiency of the reed wetland was also discussed. Average removal efficiencies of the reed （Phragmites australis） wetland were found to be 79.0% for COD, 72.2% for ammonia nitrogen （NH3-N） and 82.8% for total phosphorus （TP）. Reed planting had obvious improvement on COD and NH3-N removal efficiency when compared to an unplanted system. With the seawater proportion in the influent increasing from 20% to 30%, the TP removal efficiency improved obviously. COD removal efficiency of the reed wetland was positively correlated with HRT under high salinity condition, while excess HRT had adverse impacts on the NH3-N and TP removal. Optimal HRT for NH3-N and TP removal was 4 days. Results obtained can be beneficially used to improve the use of constructed wetlands in saline wastewater treatment.
