Sustainable Application of TDA in Stormwater Infiltration and Treatment

Abstract

The objective of this research was to determine the efficacy and cost-effectiveness of the application of t ire-derived aggregate (TOA) in stormwater treatment and management systems. We reaffirmed that TOA is an excellent means of retaining phosphate (soluble reactive phosphorus) in stormwater runoff. In addition, we found that biofilms grow on TOA flushed by river water in sufficient quantities to retain zinc and copper to below the U.S. Environmental Protection Agency's chronic toxicity criteria within one to four, 72-h flushes, designed to simulate the flushes of an underground runoff storage faci lity. A four-week antecedent dry period after the 13th flush did not cause the total loss of the biofilm, indicating that the TDA could also be used in biofilters that have high phosphate release due to degradation of compost. We can therefore conclude the following: 1) TOA is a media that can retain phosphate (SRP) for more than 72 flushes (Singh and Gulliver 2024), or roughly 8 to 9 years in the upper Midwest of the United States. 2) Biofilms growing on the TOA will retain much of the zinc, copper and iron that is released from the TOA, even when applied in surface infiltration practices. 3) The per- and polyfluoroalkyl substances (PFAS) leached from TOA were relatively low in our study and appear to be similar to typical urban concentrations, including residential land. 4) TOA that avoids disposal and can be installed as an underground stormwater storage or infiltration facility can reduce the lifetime costs of the material.