Technosols Offer a Suitable Replacement for Sand-Based Filter Media in Rain Garden Design

Area of Science:

• Environmental Science
• Geochemistry
• Civil Engineering

Background:

• Sand is a critical component in green infrastructure, but its sustainability is increasingly uncertain.
• There is a growing need for alternative materials that can perform essential functions in stormwater management.
• Technogenic materials offer a potential solution for sustainable green infrastructure development.

Purpose of the Study:

• To evaluate the efficacy of Technosols (glass, shale, and shell) as alternative materials for rain gardens.
• To assess the infiltration and pollutant-filtering capabilities of Technosols compared to traditional sand.
• To determine the suitability of Technosols for managing stormwater runoff and chemical contaminants.

Main Methods:

• Rain garden experiments were conducted using Technosols (glass, shale, shell) and sand as filter media.
• Infiltration rates and saturated hydraulic conductivities of each material were measured.
• The removal efficiency of various chemical pollutants (e.g., NH4-N, P, Cu, Pb, Zn) from synthetic stormwater was analyzed.

Main Results:

• Technosols exhibited infiltration rates comparable to sand, with significantly higher saturated hydraulic conductivities due to larger particle sizes.
• All Technosols effectively reduced concentrations of most tested pollutants, with notable exceptions for Zinc.
• Shale and shell demonstrated superior removal of Copper and Lead compared to sand, while glass also showed significant Lead removal.

Conclusions:

• Technosols, particularly glass and shell, show significant potential as sustainable alternatives to sand in green infrastructure.
• These materials offer comparable infiltration to sand while enhancing the removal of key chemical pollutants.
• Further research into Technosols can advance the development of resilient and effective stormwater management systems.