Engineered biofilter media for enhanced stormwater pollutant removal
Advanced biofiltration technology using hydrogel-biochar composites and pyrite minerals to simultaneously remove nitrate, phosphorus, heavy metals, and organic pollutants from stormwater. This low-energy solution significantly accelerates denitrification and improves multi-pollutant treatment efficiency.
Overview
Stormwater runoff carries a complex mix of pollutants including nitrogen compounds, phosphorus, heavy metals, and trace organic contaminants that pose risks to water bodies and public health. Conventional biofilters offer a low-energy treatment option but are limited by slow nitrate removal and insufficient capacity for co-existing pollutants.
This research presents an engineered biofilter system that integrates hydrogel-biochar composites and pyrite minerals into the soil media, combined with an internal water storage layer at the bottom. The approach accelerates in situ denitrification while efficiently capturing phosphorus, metals, and organic pollutants in a single treatment step.
Technical specifications
Core technology components:
- Hydrogel-biochar composites act as soil amendments that supply labile organic matter and shape microbial communities to promote denitrification, heavy metal stabilization, and organic matter degradation
- Pyrite minerals serve as a reductive media that enhances nitrate removal and supports phosphorus recovery through formation of iron-aluminum bound phosphorus
- Internal water storage layer creates anaerobic conditions at the bottom of the biofilter, stimulating microbial denitrification activity
- Multi-layer biofilter architecture enables simultaneous removal of multiple pollutant classes in one system
Key performance results from bench-scale testing:
- Ammonium removal efficiency of 83.8%
- Nitrate removal efficiency of 94.4%
- Total nitrogen removal efficiency of 91.4%
Target pollutants: Nitrate, phosphate, heavy metals, and urban-use pesticides.
Technology readiness level
The technology is currently at bench-scale validation. Hydrogel-biochar composites have been tested in laboratory biofiltration experiments demonstrating significant improvements in denitrification and pollutant stabilization. Pyrite has been validated as an effective reductive media in prior wastewater treatment studies.
Future work involves constructing a multi-layer biofilter prototype to evaluate simultaneous removal of nitrate, phosphate, heavy metals, and pesticides. Microbial community analysis using RT-qPCR and 16S rRNA gene sequencing will provide insight into treatment mechanisms, and pollutant removal models will support engineering design. The project is estimated to take one year to complete, co-led by Dr. Sunny Jiang and Dr. Lixun Zhang at the University of California, Irvine.
About University of California, Irvine
UC Irvine is a comprehensive public research university in the University of California system, known for large-scale research and a collaborative, cross-disciplinary culture. Industry engages through an adjacent research and technology park, an on-campus innovation hub that co-locates startups with corporate teams, and access to shared core laboratories across campus. Integration with a major academic health system provides pathways for clinical collaboration and translation. Research is supported by competitive federal funding from agencies such as NIH, NSF, DOE, and DOD, alongside state and industry partnerships. A central technology transfer office streamlines IP, licensing, and startup formation.
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