The reuse of old tires that often end up in landfills has a significant environmental benefit. Tire derived aggregate (TDA), a waste product from automobile tires, can be used in stormwater treatment systems and has shown to be effective at retaining phosphate. However, TDA does not prevent the leaching of metals including zinc and copper.  

Developing media for stormwater infiltration/filtration that uses TDA in combination with materials that can capture metals has several advantages. It would prevent more pollutants from being released into Minnesota’s lakes and streams, save on landfill space and reduce stormwater management costs.

“The use of TDA has been proposed in the past for use in stormwater treatment.  However, local agencies aren’t very familiar with the product being used for this application and have concerns about its potential to contaminate groundwater resources,” said Mark Hansen, city engineer, City of Coon Rapids. “Initial research is showing positive benefits for the use of TDA as a component of the stormwater treatment process, while minimizing its impacts to groundwater.  Using TDA for this application provides a great opportunity to redirect old car tires from landfills and beneficially reuse them to assist in providing stormwater treatment.”

Objectives

• Select blend materials identified in literature review and mix them in different ratios with TDA.
• Measure the pollutant removal performance from runoff, leaching of zinc and copper from TDA, and infiltration capacity of each mix.
• Analyze the observed values to choose the suitable blend material/ratio.
• Perform lab batch tests to evaluate the potential leaching or removal of polyfluoroalkyl substances (PFAs) by TDA and the blends.
• Determine impact of biofilms on the leaching of zinc and copper from the mix (Biofilms will be grown on an already defined mix of TDA with blend material).
• Conduct outreach on project results and implications to management to key stakeholder groups.

Project Details

• Estimated Start Date: 06/03/2022
• Estimated Completion Date: 06/30/2025
• Funding: Local Road Research Board
• Principal Investigator: John Gulliver
• Co-Principal Investigator: Meijun Cai
• Technical Liaison:  Mark Hansen

Details of the research study work plan and timeline are subject to change.

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