Engineered nonwoven fabric system for nitrogen and phosphorus removal in stormwater runoff

Overview

This solution addresses a critical environmental challenge: removing nitrogen- and phosphorus-based pollutants from stormwater runoff before they reach waterways. The proposed system uses two complementary nonwoven fabric types—nylon and cellulosic—stacked together as a pretreatment media. Each fabric is engineered to capture specific pollutants based on ionic charge interactions, enabling broad-spectrum contaminant removal without chemical flocculants.

Stormwater carries reactive nitrogen species and phosphorus compounds that contribute to eutrophication, harmful algal blooms, and degraded water quality in receiving streams, lakes, and estuaries. Conventional treatment relies on chemical additives and complex infrastructure. This fabric-based approach offers a simpler, more economical pretreatment step that could be integrated into existing stormwater management systems or deployed as a standalone filtration layer.

The value proposition centers on cost-effective pollutant capture using widely available textile materials, with potential applications in municipal stormwater management, industrial runoff treatment, agricultural drainage, and green infrastructure projects.

Technical specifications

Pollutant capture mechanism:

• Nylon nonwoven fabrics capture negatively charged species including NOx compounds, nitrate, nitrite, and orthophosphate. Nylon's positively charged amine groups form ionic bonds with these anionic molecules, similar to how acid dyes bind to nylon in textile dyeing processes.
• Cellulosic nonwoven fabrics capture positively charged ammonia. Cellulose surfaces carry a negative charge in water, attracting and binding ammonia species through electrostatic interaction.

System design:

• Stacking configuration combines both fabric types to address the full range of nitrogen-containing pollutants in stormwater
• Nonwoven structure engineering (fiber diameter, web architecture, basis weight, and surface area) is used to optimize absorption capacity and flow-through performance
• No chemical flocculants or coagulants required, reducing operational complexity and cost

Key features:

• Dual-pollutant targeting through complementary ionic charge interactions
• Passive treatment requiring no chemical dosing or energy input
• Modular design allowing scale-up or scale-down based on flow requirements
• Uses commodity textile materials for low-cost deployment

Technology readiness level

This technology is at an early proof-of-concept stage (TRL 2–3). Prior published research has demonstrated that fine polyamide microfiber media can achieve over 50% removal of NOx, nitrate, nitrite, and orthophosphate from stormwater without flocculants, providing a validated baseline for the nylon component.

The cellulosic fabric component for ammonia capture builds on reported interactions between cellulose and ammonia in aqueous systems, though specific stormwater application testing remains to be completed.

A planned 9-month proof-of-concept program will conduct: (1) absorption tests of NOx, nitrate, nitrite, and orthophosphate on nylon nonwoven fabrics; (2) absorption tests of ammonia on cellulosic nonwoven fabrics; and (3) total nitrogen removal testing using a stacked configuration of the best-performing fabrics from each category. Successful completion of these experiments would advance the technology toward pilot-scale validation and potential integration into stormwater treatment infrastructure.