Next Article in Journal
Permeability and Groundwater Enrichment Characteristics of the Loess-Paleosol Sequence in the Southern Chinese Loess Plateau
Previous Article in Journal
Evaluation of Flood Prediction Capability of the WRF-Hydro Model Based on Multiple Forcing Scenarios
Open AccessArticle

Importance of the Submerged Zone during Dry Periods to Nitrogen Removal in a Bioretention System

1
Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China
2
School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-Sen University, Zhuhai 519082, China
3
Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
*
Author to whom correspondence should be addressed.
Water 2020, 12(3), 876; https://doi.org/10.3390/w12030876
Received: 30 January 2020 / Revised: 3 March 2020 / Accepted: 14 March 2020 / Published: 20 March 2020
(This article belongs to the Section Urban Water Management)
Adding a submerged zone (SZ) is deemed to promote denitrification during dry periods and thus improve NO3 removal efficiency of a bioretention system. However, few studies had investigated the variation of nitrogen concentration in the SZ during dry periods and evaluated the effect of the variation on nitrogen removal of the bioretention system. Based on the experiment in a mesocosm bioretetion system with SZ, this study investigated the variation of nitrogen concentration of the system under 17 consecutive cycles of wet and dry alternation with varied rainfall amount, influent nitrogen concentration and antecedent dry periods (ADP). The results indicated that (1) during the dry periods, NH4+ concentrations in SZ showed an exponential decline trend, decreasing by 50% in 12.9 ± 7.3 h; while NO3 concentrations showed an inverse S-shape declining trend, decreasing by 50% in 18.8 ± 6.4 h; (2) during the wet periods, NO3 concentration in the effluent showed an S-shape upward trend; and at the early stage of the wet periods, the concentration was relatively low and significantly correlated with ADP, while the corresponding volume of the effluent was significantly correlated with the SZ depth; (3) in the whole experiment, the contribution of nitrogen decrease in SZ during dry periods to NH4+ and NO3 removal accounted for 12% and 92%, respectively; and the decrease of NO3 in SZ during the dry period was correlated with the influent concentration in the wet period and the length of the dry period. View Full-Text
Keywords: bioretention; nitrogen removal; submerged zone; alternate wet and dry conditions bioretention; nitrogen removal; submerged zone; alternate wet and dry conditions
Show Figures

Figure 1

MDPI and ACS Style

He, K.; Qin, H.; Wang, F.; Ding, W.; Yin, Y. Importance of the Submerged Zone during Dry Periods to Nitrogen Removal in a Bioretention System. Water 2020, 12, 876.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop