Abstract
Bioretention facilities have been widely used in the construction of Sponge City in China, but there have also been doubts about whether road runoff pollutants have adverse effects on plant growth. In response to this problem, this paper explored the effects of bioretention on the removal of pollutants and explored the effects of runoff on plant growth and physiology. The results showed that (1) the average concentration reduction rate and load removal rate of TN and NO3--N were above 70%, the average NH4+-N concentration reduction rate and load removal rate were greater than 90%, and the removal of elemental N was affected by the influent concentration. The removal effect of the four heavy metals was not very great. The average concentration reduction rate and load removal rate of heavy metals were 65.4–95.7% and 85.4–99.4%, respectively. The cumulative load removal rate of various pollutants was above 87.0%. (2) The runoff of high–concentration pollutants had a negative or no significant effects on the net photosynthesis rates (Pn), chlorophyll contents (CC), and electrolyte leakage (EL) of most plants (e.g., Iris tectorum Maxim, Rosa xanthina Lindl, and Ligustrum vicaryi). It had a significantly negative effect on the plant height of shrub plants (e.g., Rosa xanthina Lindl and Ligustrum vicaryi), but had a positive effect on Pn and CC of Iris lactea var. chinensis. (3) The runoff of low–concentration pollutants had a positive or no significant effects on the physiological indexes of herbaceous plants (e.g., Iris tectorum Maxim and Iris lactea var. chinensis), but there were no explicit conclusions regarding the physiological indicators of shrub plants (e.g., Rosa xanthina Lindl and Ligustrum vicaryi). It had no obvious effects on the plant height of these four species of plants.
Highlights
With the continuous advancement of urbanization, the drastic increase in impervious area has caused a significant decrease in the amount of rainwater infiltration
For the 16.0 mm and 33.3 mm simulated rainfall events, the average volume retention rate (VRR) of the devices were 55.3 ± 24.0% and 53.8 ± 6.2%, respectively, which was similar to the results of previous studies [22,34,35]
The VRR of 16.0 mm was slightly larger than that of 33.3 mm, and the two sets of VRRs did not reach the level of statistically significant difference (p > 0.05)
Summary
With the continuous advancement of urbanization, the drastic increase in impervious area has caused a significant decrease in the amount of rainwater infiltration. Stormwater runoff has exerted tremendous pressure on municipal drainage facilities. The pollutants trapped by stormwater runoff on impervious ground have become an important contributor of nonpoint source pollution of surface water. In China, the term “Sponge City” has been widely used since 2013 to describe a new paradigm in urban drainage planning and design. Bioretention has been an important measure during the construction of “Sponge City” in China. Bioretention facilities are increasingly regarded as sustainable rainwater control measures because of their effects in reducing runoff pollution, total surface runoff, and peak flows. The filter media can retain and slowly release rainwater into the soil through infiltration or drainpipes, thereby reducing the peak runoff and reducing the drainage pressure on municipal facilities
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
