Manual to mechanical

To respond to increasing generation of construction and demolition (C&D) debris in and around Nashville, Tennessee, Houston-based WM Inc. has invested in its Southern Services EcoPark, a 183-acre property that includes a 77-acre C&D landfill, a certified wildlife habitat and a C&D material recovery facility (MRF).

WM serves on Metro Nashville’s C&D steering committee, which has met quarterly for the last year to shape the city’s policy on what is being termed a “C&D waste crisis.”

Metro Nashville provided an update on its plans to phase in C&D recycling requirements at a March Solid Waste Region Board meeting.

C&D material comprises approximately 33 percent of all landfilled waste in Nashville, and “preventing bulky, energy-intensive and highly recyclable C&D material from being landfilled is crucial for the continued resilience, economic growth and prosperity of this region,” according to Nashville and Davidson County.

The Davidson County Solid Waste Region Board issued its 2022 annual report earlier this year, which notes end markets are needed for C&D materials, including hard-to-recycle materials and gypsum, which is particularly challenging, according to WM.

The company announced plans in May to construct a new 52,000-square-foot C&D MRF featuring vibratory screens, trommels and more, at its Southern Services EcoPark. The facility can accept up to 1,200 tons per day of C&D material, which is more than 10 times its former capacity.

The MRF became fully operational in September.

WM Area Director of Disposal Operations Don Gentilcore says the C&D recycling facility is located on a 22-acre parcel within the Southern Services EcoPark, which is in an industrial area about 15 minutes from downtown Nashville.

Gentilcore discusses WM’s design choices for its new C&D MRF as well as the reasoning behind them with Construction & Demolition Recycling (C&DR) in the following Q&A.

C&DR: What factors drove the need for the new C&D MRF?

Don Gentilcore (DG): There are multiple factors that have led to the investment and design of the enhanced construction and demolition recycling facility co-located at Southern Services EcoPark.

In the past 10 years, C&D waste volume in Nashville has exponentially increased due to the city’s rapid development along with several unexpected natural disasters. WM’s Southern Services C&D landfill is the only C&D landfill in Davidson County, where Nashville is located.

The need for a more robust C&D recycling option, such as an automated C&D recycling facility, is multifaceted. Davidson County is simply running out of room to dispose of C&D material. Without an in-county disposal facility, projects face increased disposal costs and longer transportation times.

WM is investing to divert more materials and provide sustainability solutions to our customers, and this new investment in Nashville’s C&D recycling will help deliver those solutions. C&D waste makes up around 30 percent of the county’s waste stream, yet only about 1 percent of that material is currently being recycled. We anticipate that 50 to 60 percent of the material will [now] be able to be recovered.

C&DR: Can you describe WM’s C&D recycling operation prior to this upgrade?

DG: We have invested in a significant upgrade to an existing facility. The WM C&D recycling facility (co-located at our Southern Services EcoPark, which also is the site of our C&D landfill and certified wildlife habitat) has been operating as one of the only mixed C&D recycling facilities in Davidson County since 2011.

This has historically been a small, hand-sort operation with minimal capacity that has been used primarily to help contractors meet LEED [Leadership in Energy and Environmental Design] project goals.

The operation was totally revamped from an open-air sorting process using a combination of equipment (loaders and grapple excavators) with a manual hand-sorting process.

C&DR: What are some advantages of the facility’s location?

DG: Advantages of the C&D recycling facility include convenient highway access and being co-located at the EcoPark with our Southern Services C&D landfill, which allows for cost-effective management of residuals and reuse of recovered soils and aggregate.

In addition, ample surrounding acreage allows for efficient traffic flow. The new equipment is set up to handle large volumes and various materials.

C&DR: What processing equipment was added to WM’s C&D MRF and why?

DG: We collaborated with Sherbrooke OEM from Quebec, Canada, for equipment design and installation. WM has worked with Sherbrooke OEM for other C&D processing facilities and has been very pleased with the performance of their sort systems.

The upgraded facility incorporates … automated sorting equipment that is expected to increase throughput from 150 tons per day to approximately 1,000 tons per day.

We are using trommels, vibratory screens, air classifiers and magnets to perform different aspects of the sorting process.

Our goal was to achieve a level of automation for the sorting process that maximizes material recovery based on the research and data collection from our recent collaboration with Tennessee State University.

In 2021, WM committed $300,000 over three years to Tennessee State University. As part of that commitment, WM is providing research grant funding to the university which is focused on waste characterization studies and alternative end-market uses for C&D material.

C&DR: How has the building or site layout affected equipment selection for the MRF?

DG: We are fortunate to have ample space for the new building, which allowed us to design an efficient and well-laid-out system without having to compromise on space.

Traffic flow was an important aspect of the design to ensure smooth operation, and customer access was a priority.

Because the facility is co-located with WM’s Southern Services C&D Landfill, we were able to use the existing roadways and scale systems to support this expanded operation.

C&DR: How has the projected waste stream affected WM’s equipment choices?

DG: We leveraged data collected from the incoming C&D materials and insights from other operating WM C&D recycling facilities to help customize the equipment design and sort lines.

C&DR: How many employees work at the facility and is that number likely to change?

DG: The previous C&D sorting facility employed approximately 10 people, and we expect the total number of employees to increase to more than 20 based on the expected increased volume and additional sorting capacity. In addition to the mechanical sorting equipment, the facility will have an elevated manual sorting line.

Don Gentilcore, WM area director of disposal operations, is based in Nashville, Tennessee, and can be reached at dgentilc@wm.com.