KNOXVILLE, Tenn. (AP) The state is going green in a nearly $1.3 million landscaping job for an expanded Interstate 40/75 interchange, requiring for the first time the use of recycled compost material as a soil enhancer before installing thousands of trees and shrubs.
The goal is to save money and help the environment. Healthy plants and trees don’t need to be replaced as often. And putting recycled yard waste to work as compost is better than sending it to the landfill.
“When you invest that kind of money into an elaborate landscaping project, everybody benefits if you can treat the soil [with recycled and composted material] and get those plants established,” said Travis Brickey, spokesman of the Tennessee Department of Transportation.
Advocates say compost helps the soil retain water and fertilizer, improves soil structure, adds nutrients and encourages root growth.
Some 3,000 trees, 1,000 shrubs, 13,000 tree seedlings and an array of native grasses and wildflowers are being installed at the 20-acre (8 ha) project. Work began in September and is set to be done by June.
The terrain includes steep hillsides and grassy medians amid entrance and exit ramps and bridges feeding Papermill Drive and Weisgarber Road.
Laying the foundation will be 5,000 cu. yd. (3,800 cu m) — or 300 dump-truck loads — of composted organic material supplied by Natural Resources Recovery in Knoxville.
“The area has a lot of poor soil,” said Tim Warren, owner of project contractor CHW Landscaping. “The compost can be mixed in with the soil to give it organic material.”
Natural Resources Recovery (NRR), headquartered in Baton Rouge, La., has been operating wood and yard waste recycling centers in Knox County since 2003, recycling nearly 16,500 tons (15,000 t) of green waste last year alone.
The company holds one of only two composting permits in Tennessee, NRR President Sid Brian said. The other is in Sevier County.
“It’s not solely important to me” that the state is using this company’s products for the interchange project, Brian said. “What I’m most excited about is that their decision to use compost promotes the recycling and beneficial reuse of materials that otherwise would go into landfills.”
TDOT decided to use compost in the Knoxville job after seeing similar highway landscaping projects in North Carolina, Ohio and Texas successfully establish plants using compost.