Study on ecological treatment of city tail water in China: a review

The discharge of city tail water in China has aggravated the pollution of rivers, lakes, and groundwater. Compared with other methods, ecological treatment has advantages in cost and effect. Based on the review of literature, the water quality of city tail water in China was analyzed, and the treatment of city tail water by constructed wetlands (CWs), ecological pond, and ecological floating bed (EFB) was discussed. The pollution indicator concentration of city tail water is higher than that of class IV water standards for rivers and lakes. The maximum removal rates of NH4+-N, TP, and TN in city tail water by CWs are more than 85%. The EFB technology plays an important role in the treatment process of city tail water, and the proportion of substrate treatment is higher in substrate, plant, and microorganism. The economic value of plant is also an important issue to be considered in EFB treatment of city tail water. There are many researches on the single technology of EFB, CWs, and ecological pond for the treatment of city tail water, but the comprehensive technology research of two or more is lacking. This study is of great significance to promote the ecological treatment of city tail water.