Nonwoven Geotextiles for Treatment of Polluted Water

The expansion of geosynthetic use has followed discovery of applications where they provide new, better or alternative solutions to infrastructure problems. This paper describes ongoing research to employ the phenomena that geotextiles host microorganism growth to the protection of drinking water sources and stream habitats. The basic concept is to filter organic pollutants from polluted waters before discharge, and use a biomass in the internal porosity to degrade the intercepted solids to stable end products. Bench scale experiments show that municipal wastewater can be treated to produce an effluent that exceeds the secondary treatment standards intended to prevent oxygen depletion in receiving streams. The project is now focused on developing new "Best Management Practices" (BMPs) for intermittent wet weather flows such as urban runoff and combined sewer overflows. The target pollutants are suspended solids and pathogens. Most current BMPs require large surface area and significant new pipe infrastructure. This is frequently impractical for application at urban sites with limited surface space and an existing pipe network and outfall. To treat wet weather discharges with minimal local disruption; compact, subsurface, end-of-pipe retrofit treatment units are needed. All work to date has employed available products. The goal is to quantify the influence of measurable geotextile parameters (permittivity, porosity, etc.) on hydraulic and treatment efficiency. The ultimate result anticipated is a template for manufacture of new products with optimized internal structures for this new application.