Hydrologic and water quality performance of alaboratory scale bioretention unit
Jun Xia, Hongping Wang, RichardL. Stanford, Guoyan Pan, Shaw L. Yu
Frontiers of Environmental Science & Engineering
2018,
Volume 12,
Issue 1,
doi:
10.1007/s11783-018-1011-5
Abstract:
A bioretention unit (BRU) or cell is a green infrastructurepractice that is widely used as a low impact development (LID) techniquefor urban stormwater management. Bioretention is considered a goodfit for use in China’s sponge city construction projects. However,studies on bioretention design, which incorporates site-specific environmentaland social-economic conditions in China are still very much needed.In this study, an experimental BRU, consisted of two cells plantedwith and ,was tested with eighteen synthesizedstorm events. Three levels (high, median, low) of flows and concentrationsof pollutants (TN, TP and COD) were fed to the BRU and the performanceof which was examined. The results showed that the BRU not only delayedand lowered the peak flows but also removed TN, TP and COD in variousways and to different extents. Under the high, medium and low inflowrate conditions, the outflow peaks were delayed for at least 13 minutesand lowered at least 52%. The two cells stored a maximum of 231 mmand 265 mm for turf grass and respectively. For both cells the total depth available for storagewas 1,220 mm, including a maximum 110 mm deep ponding area. The largestinfiltrate rate was 206 mm/h for both cells with different plants.For the eighteen events, TP and COD were removed at least 60% and42% by mean concentration, and 65% and 49% by total load, respectively.In the reservoir layer, the efficiency ratio of removal of TN, TPand COD were 52%, 8% and 38%, respectively, within 5 days after runoffevents stopped. Furthermore, the engineering implication of the hydrologicaland water quality performances in sponge city construction projectsis discussed.
Keywords：
Bioretention unit
Spongecity
Stormwater runoff
Peak reduction
Pollutant removal
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