Addressing the research needs for the sustainable application of TDA in stormwater infiltration/treatment.

Project summary:

Tire derived aggregates (TDA), a waste product from automobile tires, are utilized in many engineering applications. There are questions about TDA's suitability for use as a stormwater infiltration/filtration media. A recent investigation by the principal investigator's (PI's) team [Professor John S Gulliver (PI) and Raymond Hojalski (Co-PI), "Tire Derived Aggregate for Stormwater Treatment," seed research funded by MnDRIVE] on the applicability of two-inch TDA for stormwater treatment has shown good phosphate retention but with substantial leaching of zinc and some copper. The overall objective of this research is to develop a system of media that will utilize the phosphate-retaining characteristic of TDA while reducing zinc and copper release. There are many materials that can capture metals--such as compost, peat, biochar, and various amines and clay particles--and the goal of this study will be to develop the optimum combination that will reduce metal leaching while allowing for phosphate retention. The mixtures will be testing the potentials to remove per- and polyfluoroalkyl substances (PFAS) from water. Biofilms will also adsorb zinc and copper, so a study of biofilm growth and adsorption of these two metals will be a secondary objective. In addition, researchers will run longevity studies with multiple stormwater flushes into TDA to simulate those occurring over many years. Education and outreach to practitioners from cities, counties, MnDOT, and corresponding consulting firms on the proper utilization of TDA will be the final objective of the study.