Engineered urban wetland systems for nutrient removal in stormwater infrastructure

Overview

This research program focuses on engineering robust nature-based stormwater control systems that harness the natural biogeochemistry of wetlands at small urban scales. By integrating wetland processes with conventional stormwater infrastructure such as bioretention and biofiltration, the technology targets simultaneous removal of nitrogen, phosphorus, carbon, and metals, while reducing sediment transport and enhancing biodiversity and ecological habitat. The approach is designed to function reliably under the highly variable flow and loading conditions typical of urban stormwater systems, offering municipalities and developers a sustainable, resilient alternative or supplement to traditional gray infrastructure.

Technical specifications

Core approach:

• Adapts the self-organized, self-maintaining biogeochemistry of natural wetlands to function at urban scales
• Combines engineered wetland mesocosms with bioretention, biofiltration, or filtration systems
• Leverages nature-based processes driven by renewable energy sources such as solar radiation and gravity

Key technical features:

• High denitrification rates maintained even at low temperatures, extending treatment performance across seasons
• Native wetland plant selection and testing for hardiness under pollutant loading, phosphorus uptake, and variable flow conditions
• Subsurface microbial community profiling using shotgun metagenomics to characterize taxonomic composition and functional potential as a function of plantings, time, and pollutant loading
• Design parameters developed through controlled mesocosm experiments simulating high, average, and low storm events using synthetic stormwater
• Mesocosm sizing engineered to accommodate extreme flow conditions with minimum retention times targeting at least 50% total nitrogen removal

Technology readiness level

The research is at the mesocosm validation stage. Three urban wetland mesocosms will be designed and operated under varied storm event conditions to quantify removal of nitrogen, phosphorus, carbon, and metals and to establish engineering design parameters. Prior work by the research group has demonstrated that high denitrification rates can be sustained at low temperatures, and the broader use of treatment wetlands for organic and nutrient removal in rural settings is well established. The program extends these proven principles to urban green infrastructure applications, with current efforts focused on developing scalable design criteria for nutrient removal under realistic urban stormwater conditions.