Performance Evaluation of Enhanced Bioretention Systems in Removing Dissolved Nutrients in Stormwater Runoff

Abstract

Bioretention has great potential in managing and purifying urban stormwater runoff. However, information regarding the removal of nutrients in bioretention systems with the use of media, plants, and saturated areas is still limited. In this study, three devices of control, conventional bioretention (DS), and strengthened bioretention (SZ) were investigated to enhance the simultaneous removal of nitrogen and phosphorus. The experimental column SZ showed the best performance for total phosphorus (TP), ammonia (NH4+-N) and total nitrogen (TN) removal (85.6–92.4%, 83.1–92.7%, 57.1–74.1%, respectively), whereas DS columns performed poorly for NH4+-N removal (43.6–81.2%) under different conditions. For the removal of nitrate, the columns of Control and DS exhibited negative performance (−14.3% and −8.2%) in a typical event. Further evaluation of water quality revealed that in the early stages of rainfall, the effluent of the SZ column was able to reach quality standards of Grade IV for surface water in China. Moreover, although the ion-exchange and phosphate precipitation occurred on the surface of the media, which were placed in the saturation zone, it did not change the surface crystal structure.

Stormwater Filtration Performance for the Ecosol Storm Pit (Class 2): Statistical Analysis of Field Data

“…However, concentration levels within [21] were less than half those encountered within this study. In consideration of TN and TP, it is important to note that high removal efficiencies are achievable within retention-based systems, for example the bio-retention work from [22]. However, these systems are typically a secondary treatment option, as opposed to the Ecosol Storm Pit (Class 2), which is intended as an at-source treatment.…”

Enhancing nitrate and phosphorus removal from stormwater in a fold-flow bioretention system with saturated zones

“…The upper layer was filled with quartz sand that is performed as permeability and can reduce the risk of blockage in the bioretention facilities (Glaister et al 2014). The upper layer was packed with low permeability, which can increase the hydraulic retention time and create an anaerobic/anoxic zone (Sun et al 2018;Qiu et al 2019;Luo et al 2020). The height of the aquifer is 100 mm, existing between the overburden and the planting soil layer, which plays a certain role in regulating the amount of rainwater in order to facilitate the follow-up.…”

Reduction in Nitrogen Exports from Stormflow after Conversion of a Dry Detention Basin to a Stormwater Wetland

“…Urban runoff is one of the most common causes of surface water impairment [1]. Hard and impervious surfaces, including asphalt parking lots, roads, buildings, and houses cover soil and thus reduce infiltration capacity leading to more runoff during rain events [2]. As the global population increases, so too will the coverage of impervious surface [3].…”

“…Based on those numbers, the nitrogen removal efficiency via denitrification would not exceed 30% unless a higher percentage of the total nitrogen entering the SCM was transformed to NO 3 − or the transformation occurred at the entrance of the control measure, and NO 3 − was exposed to denitrifying conditions prior to exiting. It is possible that organic nitrogen may mineralize to NH 4 + , a process called ammonification [20], and under oxic conditions ammonium (NH 4 + ) can rapidly undergo nitrification [2]. These steps would enable subsequent denitrification if alternating oxic and anoxic conditions are found within the SCM along with other suitable environmental conditions.…”