TDA Continues To Perform In Removing Contaminants From Stormwater

A main objective of a new research project underway at Michigan Tech is to test the effectiveness of TDA Blocks as a filtration medium for stormwater runoff

Professor Zhanping You, Michigan Tech University and Dewayne Rodgers, Claire County, Michigan, are investigating the potential of capturing stormwater first flush contaminants like microplastics and 6PPD-quinone (6PPD-Q) using a shallow trench filled with TDA Blocks on the shoulder of Mannsiding Road in Clare County. Their work is part of a research project launched by Clare County in collaboration between  Michigan Technological University, Clare County and TDA manufacturers.

The project is an on-site field experiment to evaluate the real-world performance of the TDA  Blocks as a sustainable infrastructure solution, which uses recycled materials to protect local waterways. TDA Blocks are a key component of the project.  These TDA blocks are made of pre-compressed ASTM 6270-B shredded tire aggregate produced from end-of-life tires and wrapped in Tensar fabric.

The Tensar-wrapped TDA is encased in a metal wire gabion cage that can be easily stored, transported, and ultimately installed at the job site. Metal used for structure (wire cage) is ungalvanized, so no issues with zinc. The TDA blocks are 1200 pounds, contain shredded tire material from 60 end-of-life tires and measure 30 x 30 x 60.

They have a 50 percent void space, making them an effective medium for receiving stormwater first flush which is often the most contaminated flow from the road surface. Samples are collected during the first flush of a storm event, which is the initial period of runoff that typically occurs within the first 30 minutes of the flow after at least 72 hours of dry weather. By capturing these pollutants, the project aims to prevent them from entering the adjacent open body of water and improve the downstream water

Michigan Tech researchers are conducting water sampling along the roadway, testing and documenting the levels of contaminants before and after the TDA Blocks are installed. The baseline water samples collected from the roadway section are then tested and documented for the presence of specific contaminants, including microplastics and 6PPD-Q.

The TDA blocks were installed in October 2025 and are scheduled for ongoing research through Spring 2026, which will cover snow melt and Spring rain events. The expectation is that the TDA Blocks, surrounded by soil, will successfully capture these contaminants, thereby removing them from the downstream watershed.

This field study complements previous lab-scale column and batch experiments on TDA performance, which have shown that TDA can retain phosphates and that biofilms growing on the TDA can retain metals like zinc and copper, while also noting some leaching of certain metals. The current field test is designed to provide real-world data on the effectiveness of TDA systems in capturing specific urban runoff contaminants.

A grab sample method is used, where a clean sample bottle, often attached to a pole for safety and to avoid contamination, is directly placed in the flowing water.

The sample is collected as close to the discharge point as possible to capture contaminants before they mix with other water bodies. Professor You and his team conducted background testing prior to construction and continued data collection during the project.

Samples were sent to a certified lab where a combination of analytical techniques and standard laboratory methods are used to provide a comprehensive baseline assessment of both contaminants.

Stormwater samples, typically collected in amber or glass bottles with PTFE-lined caps to prevent photodegradation and minimize sorption of the chemical to sample container walls, are typically filtered to remove suspended materials, although some whole-water  approaches are being developed to include particles to which 6PPD-quinone may sorb.

The TDA blocks were developed by industry pioneer Monte Niemi, president of First State Tire Recycling to provide user-friendly packaging for TDA, making it easier to integrate in various designs and construction projects.

“These blocks offer a convenient solution for swiftly installing an underground stormwater collection system, specifically for first flush scenarios,” Niemi said. The Clare County project is  the first to showcase this technology.

Numerous projects across the United States, particularly in Minnesota and California, have successfully used tire-derived aggregate (TDA) for various aspects of stormwater management. More than 25 TDA Infiltration Galleries have been approved and installed since 2005, Niemi, said.

Researchers at the University of Minnesota have conducted extensive lab-scale and field studies on TDA for stormwater treatment. Their findings suggest that TDA is effective at retaining phosphate and can host a beneficial biofilm that captures and retains heavy metals, demonstrating strong potential for safe, cost-effective, and environmentally friendly underground stormwater systems. The Michigan EGLE Grant Program has been instrumental in the development of  the TDA Blocks, Niemi said.

Grant funding from a Market Development Grant from the Michigan Department of Environment, Great Lakes, and Energy (EGLE) Program, plays a large role in producing packaged TDA blocks and products and helping them get into testing and the open marketplace, Niemi said. “Their support has been instrumental in helping establish credible data on the benefits and capabilities of TDA,” he said.

© Scrap Tire News, December 2025