Highway Department explores use of biochar in invasive species management
“In the simplest of terms, you can think about it as just like supercharged charcoal,” Cook County Highway Department Engineer Robbie Kimmel-Hass told WTIP, describing a material called biochar.
In addition to maintaining many miles of roads and bridges that fall under their purview, the Highway Department also plays a role in managing invasive species in the county. And that is where biochar comes in.
Kimmel-Hass explained that invasive species management is conducted in large part by the agriculture inspector and environmental technician. This includes addressing invasive and noxious weeds, with both public education and plant removal. The county is looking to acquire biochar kilns in order to better dispose of the potentially harmful plants.
“We just kind of cut them and lay them down and let them dry out,” Kimmel said. “So you can imagine the space requirements for something like that. And also, you know, there’s the risk of contamination too.”
Biochar is made similarly to charcoal, but the result is a less dense product, which Kimmel-Hass compared to sponges. The United States Department of Agriculture lists ways that incorporating biochar can impact soil quality, including, “improving soil health, raising soil pH, remediating polluted soils, sequestering carbon, lowering greenhouse gas emissions, and improving soil moisture.”
Once the program is launched, Kimmel-Hass said the plan is for biochar produced during plant removal to be used to enhance the soil in both areas of invasive species mitigation efforts, and around highway department projects, in order to encourage revegetation. A longer term goal, he said, is to create a program that would allow the public to bring their invasive plant waste to a biochar kiln.
Kimmel-Hass said purchasing kilns, likely two of them, would cost $10,000-$20,000. The highway department has applied for funding through the Great Lakes Restoration Initiative, however, the status of that application is unknown due to the federal discretionary spending freeze. If the funding for buying kilns does not materialize, Kimmel-Hass said the department may be able to fabricate some equipment in-house, in order to further the project.
Whether the Highway Department ends up purchasing kilns or fabricating them, Kimmel-Hass said the hope is to have at least one ready for use this summer.
WTIP’s Kirsten Wisniewski spoke to Highway Department Engineer Robbie Kimmel-Hass live on DayBreak. Audio of that interview is below.
Kirsten Wisniewski March 7, 2025
