Constructed wetlands for wastewater treatment in Mainland China: two decades of experience

摘要

Constructed wetlands (CWs) have been applied for wastewater treatment since 1987 in Mainland China. There were about 150 public owned CWs operated to treat different types of wastewater, including urban domestic wastewater, rural sewage, effluent from secondary treatment, industrial wastewater, urban and agricultural runoff. About 44% of the CWs are designed for urban and rural sewage treatment. Hybrid CW takes a majority role for wastewater treatment in China. There are 24 full-scale hybrid CWs among the surveyed 59 systems in this paper. The most frequently used filtration media for vegetated beds are gravel and cobble. Phragmites australis is the dominate plant used in CWs in north China, while cyperus alternifolius and Typha latifolia are commonly applied in south China. The statistical average removal efficiencies of CWs for industrial wastewater treatment are the highest in terms of COD and BOD_5, followed by the efficiencies of treating urban domestic wastewater, rural sewage, effluent from secondary treatment, urban and agricultural runoff in a decline order with a revise trend of the designed hydraulic loading rates.