Removal of tire wear in stormwater tanks: In Situ Microflotation with TGA TED-GC/MS Analysis

The ongoing urbanization and progressive sealing of landscapes have exacerbated surface runoff, mobilizing pollutants such as Total Suspended Solids (TSS) and microplastics (MPs), including tire and road wear particles (TRWP). The effective removal of these pollutants is imperative to meet increasingly stringent water quality regulations. Sedimentation tanks, widely deployed for the treatment of urban runoff, are often insufficient in achieving the necessary pollutant retention efficiencies, especially for particles below 63 µm. Long-term monitoring of a sedimentation tank (mixed area with pollution categories I - III, as per DWA A-102-2) in Paderborn, Germany, verified that the actual retention efficiency for TSS63 (particles < 63 µm) fell significantly below the theoretical benchmark of 49,3%%, required to meet pollution category I standards. The observed inefficiency suggests that tire wear particles, which are part of the TSS, are also insufficiently retained.

To address these shortcomings, we propose a novel, cost-effective, and scalable solution in the form of a microflotation-based system. This innovative technology employs controlled microbubble generation (mean diameter:45 µm) to exploit the hydrophobic properties of microplastics, facilitating their efficient separation from water. This in-situ microflotation (ISM) technology can be easily retrofitted into existing stormwater retention basins.

In this context, the focus in the presentation shown within the webinar is on the assessment of the removal of tire wear particles (TWP) in existing stormwater sedimentation tanks using in-situ microflotation. Hereby, thermal extraction desorption - gas chromatography/mass spectrometry (TGA TED-GC/MS) analysis was performed regarding the qualification and quantification of tire wear particles, as it is a state-of-the-art technology for this purpose.

Within the long-term monitoring of the sedimentation tank mentioned, TGA TED-GC/MS measurements show that tire wear retention efficiencies can be strongly increased by using microflotation.
Hence, the proposed system provides a benchmark for sustainable and efficient water treatment technologies, aligning with contemporary goals of resource efficiency and environmental protection.

Summary of contents

• Water treatment
• Microplastic pollution
• Qualification and quantification of tire wear particles were performed using TGA TED-GC/MS
• Monitoring of sedimentation tank
• Pilot-scale in-situ microflotation
• Retention efficiency