The effect of nutrients removal for bio-retention system in rainwater runoff

Bio-retention was regarded as one of the effective control measure of the urban non-point pollution. And the build and study of the bio-retention was very seldom presented in China. Based on the characteristic of the rainwater runoff in Beijing, we constructed the bio-retention system in this study. The nutrients were selected to analyze the retention conditions and the effect of pollutants removing in this system. The simulating process of runoff was considered from water quality and water quantity. The results show that the TP, OP and TN with the good removing rate in the designed bio-retention system. The system with plants had better remove efficiencies than the system without plants. Except for TN, there is the positive correlation between the remove rate of the other pollutants and water quality of initial rainfall runoff. However, there are no clear rules between the flow rate of rainwater and the removal rate of pollutants.