Strategic in-stream systems (STRAINS): nature-based retrofits for urban water infrastructure
STRAINS is a modular, nature-based treatment system designed to retrofit urban grey water infrastructure. Using locally sourced substrates and stress-tolerant plants, it captures solid waste, settles sediment, and biofiltrates contaminants from stormwater and wastewater before they reach downstream waterways.
Overview
Urban surface water degradation affects communities across every socio-economic level worldwide, with the most acute impacts felt in megacities of the global south. Strategic In-stream Systems (STRAINS) offers a practical, low-cost approach to improving water quality by retrofitting existing urban streams and drainage channels with simple nature-based solutions. The system addresses stormwater and wastewater contamination at the source, preventing pollutants from reaching downstream lakes and rivers.
The solution is designed for rapid, affordable deployment and can be integrated into traditional grey infrastructure at multiple scales. By deploying networked units throughout a catchment, STRAINS delivers cumulative water quality improvements over an entire urban watershed.
Technical specifications
STRAINS operates through three modular treatment stages:
- Stage 1 – Solid waste capture: Diverts and collects floating and coarse solid debris from urban water flows
- Stage 2 – Sediment settling: Slows water velocity to allow suspended solids and particulate matter to settle out of the water column
- Stage 3 – Biofiltration: Uses locally available substrates such as gravel and terracotta, combined with stress-tolerant aquatic plant species, to remove dissolved biological and chemical contaminants including nitrogen
Key features:
- Operates without chemical or energy inputs, relying on natural processes
- Uses locally sourced, low-cost materials suitable for diverse geographic contexts
- Modular design enables flexible deployment at varying scales
- Networked performance improves with multiple units across a catchment
- Compatible with existing grey infrastructure, enabling straightforward retrofitting
Technology readiness level
STRAINS has been validated through successful laboratory and field-scale studies in Bangalore, India, demonstrating significant removal efficiencies for physical, biological, and chemical contaminants using both synthetic and real wastewater and stormwater flows. These initial studies have confirmed the system's effectiveness with local substrates and specialized hyperaccumulating plant species.
The next phase involves constructing a full-scale pilot intervention in the field and evaluating pollutant removal performance over a one-year period. In parallel, watershed-scale modelling using SWMM5 will assess cumulative water quality impacts across an entire urban catchment. The interdisciplinary research team brings expertise in design, engineering, hydrology, and community development, supported by the Green Infrastructure Landscape Lab (GILL) at Texas Tech University and the dedicated water lab at the Ashoka Trust for Research in Ecology and Environment (ATREE) in Bangalore.
About Texas Tech University
Texas Tech University is a large, comprehensive public research university in Lubbock and an anchor of the Texas Tech University System, coupling academic breadth with applied, collaborative research. Industry partners engage through a research park and incubator, co-located labs, shared core facilities, and West Texas field sites for pilot-scale and real-world testing. Proximity to the Permian Basin and regional manufacturing, plus collaboration with the system’s health sciences center, creates clear pathways for product development, clinical translation, and talent pipelines. Research is supported by competitive federal funding from agencies such as NSF, DOE, USDA, NIH, DoD, and NASA, and a dedicated technology transfer office streamlines IP, licensing, startup formation, and corporate contracting.
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