Bioretention Design Modifications Increase the Simulated Capture of Hydrophobic and Hydrophilic Trace Organic Compounds

Abstract

Stormwater rapidly moves trace organic contaminants (TrOCs) from the built environment to the aquatic environment. Bioretention cells reduce loadings of some TrOCs, but they struggle with hydrophilic compounds. Herein, we assessed the potential to enhance TrOC removal via changes in bioretention system design by simulating the fate of seven high-priority stormwater TrOCs (e.g., PFOA, 6PPD-quinone, PAHs) with log K OC values between −1.5 and 6.74 in a bioretention cell. We evaluated eight design and management interventions for three illustrative use cases representing a highway, a residential area, and an airport. We suggest two metrics of performance: mass advected to the sewer network, which poses an acute risk to aquatic ecosystems, and total mass advected from the system, which poses a longer-term risk for persistent compounds. The optimized designs for each use case reduced effluent loadings of all but the most polar compound (PFOA) to <5% of influent mass. Our results suggest that having the largest possible system area allowed bioretention systems to provide benefits during larger events, which improved performance for all compounds. To improve performance for the most hydrophilic TrOCs, an amendment like biochar was necessary; field-scale research is needed to confirm this result. Our results showed that changing the design of bioretention systems can allow them to effectively capture TrOCs with a wide range of physicochemical properties, protecting human health and aquatic species from chemical impacts.

Development of composite alginate bead media with encapsulated sorptive materials and microorganisms to bioaugment green stormwater infrastructure

“…3 Indeed, amended bioretention media are capable of capturing increased quantities of trace organic contaminants. 123 BioSorp beads could be incorporated into new bioretention systems or amended post-construction into existing GSI systems for bioaugmentation. BioSorp beads are designed to directly address the wicked problem of hydrophilic compounds by: (1) rapidly capturing contaminants onto the black carbon materials via chemical sorption during the rapid infiltration stages and (2) encapsulating and bioaugmenting contaminant degrading microorganisms in GSI systems.…”