Bioactive biological soil crust filters for continuous nitrogen and phosphorus removal from stormwater runoff

Overview

This solution addresses the challenge of removing multiple nitrogen species from stormwater runoff (SWR) through a novel bioactive filter technology. The approach uses biological soil crusts (BSCs) embedded in particulate bead filters, which are deployed in serialized stormwater filter boxes for continuous, one-stop treatment of nitrogen-rich runoff. The system targets chemical-free removal of nitrate, ammonium, and dissolved organic nitrogen, along with phosphorus, making it suitable for urban and agricultural stormwater management applications.

The technology builds on prior validated work demonstrating over 98% nitrogen and phosphorus removal using microalgal polymeric beads in batch and semi-continuous modes. By integrating microbial consortia with proven high biological nitrogen removal activity into engineered bead filters, the solution offers a scalable, environmentally friendly alternative to conventional chemical treatment methods.

Technical specifications

Key features:

• Bioactive bead filters containing microbial consortia including species such as Microcoleus and Pseudomonas for broad-spectrum nitrogen removal
• Serialized treatment bed design enabling continuous operation with easy separation of treated stormwater
• Multi-species N removal capability targeting nitrate, ammonium, and dissolved organic nitrogen simultaneously
• Combined nutrient removal addressing both nitrogen and phosphorus in a single system
• Optimized bead properties including density, surface area, and diffusivity tailored for stormwater conditions
• Mass transfer modeling for hydraulic load optimization, retention time, and removal efficiency
• Scalable architecture designed for pilot systems with approximately 100L hydraulic capacity, readily scaleable for higher runoff rates

Technology readiness level

The technology is currently at a mid-stage development level, supported by substantial preliminary validation. Prior work has demonstrated greater than 98% nitrogen and phosphorus removal efficiency using microalgal polymeric beads in batch and semi-continuous treatment modes. Field-scale research on stormwater biofilters incorporating biological soil crusts has also been conducted in urban settings.

Future validation will proceed through a structured plan: enriching stable microbial consortia under stormwater conditions, designing and optimizing BSC bead properties, constructing a pilot-scale serialized treatment system, generating benchmark data for varying runoff rates, developing mass transfer models for system optimization, and performing scale-up analyses for higher flow conditions. The system is designed to be readily scaleable from pilot to full deployment.