Notice of Retraction Analysis on surface water quality purifying effect of constructed wetland in north area of China

To study the purifying effect for surface water quality, the long-term monitoring data of HeiTuwa constructed wetland located at the above of Guanting Reservoir were applied to analyze water quality purifying effect of overall constructed wetland system and three different areas of subsurface flow constructed wetland. The results showed that water quality removal rate reached more than 40% averagely; Water quality standard changed from class five to class three and four; the overall water quality purification effect is more obvious. Water quality purification effect of constructed wetland at normal temperature phase was better than the transition period and low-temperature period. Water quality purification effect of the first district was best in three purification districts of subsurface flow constructed wetland, followed by the second district and the third zone. In addition, three kinds of plants were analyzed to find Pistia stratiotes has the best purifying effect. Finally, the study provided the measurement of operation and management for constructed wetland in north area of China.