Evaluation of Aquatic Plants for Water Purification in the Xixi Wetland in Hangzhou, China

A lot of plants have been confirmed to be capable of purifying water. To screen for plants for water purification in the Xixi wetland, water was sampled from the Xixi wetland for indoor experiment. Four kinds of aquatic plants of different growth type (Eichhornia crassipe, Ceratophyllum demersum, Acorus calamus and Lemna minor) were selected for culture using the water under test. After 45 days of culture, obvious water quality improvement was observed for all of the plants. The BOD5, COD, TN and TP value of the water was decreased by 64.80%, 58.73%, 87.52% and 90.06%, respectively by the plants in the experiment. Based on a comprehensive analysis, Eichhornia crassipe and Ceratophyllum demersum showed high efficiency in water purification. Therefore, these two kinds of aquatic plants are suggested to be planted more in Xixi wetland.