C&D recycling facilities use many methods to separate materials by type and size. Picking lines are useful at either removing contaminants or larger pieces of debris, and screening further separates fines from midsize material. The smaller the material gets, the harder it can be to effectively hand sort.
Baumann’s Recycling Center opened in Cleveland in 2011. At the time, manual sorting stations were used at various stages of the material recovery process.
According to Bill Baumann, president of parent company, Baumann Enterprises, manual sorting was only capturing about 30 percent of the recyclable wood. This wasn’t good enough for Baumann, who says he tries to send as little to the landfill as possible.
In January, Baumann’s Recycling Center installed an optical sorter to help improve wood recovery rates. As material zips by on a high-speed belt, the optical sorter uses infrared technology to read different material types. Because wood has its own signature, it is detected from the stream.
While the rest of the material stays on the belt, the wood is ejected from the stream. It falls onto a separate belt, which creates a clean pile of wood. The wood is prepped for sale as either mulch or boiler fuel, depending on the time of year.
Baumann says the optical sorter has led to a big boost in production. “It is a huge difference,” he says. “I am getting at least 85 percent of the wood out of the material.”
Jeremie Bourgeois, project manager of Sherbrooke OEM, Sherbrooke, Quebec, says Baumann’s has always been effective at screening overs and unders.
Not only can wood be targeted for optical sorting at C&D recycling facilities, a host of other materials can be recovered using the technology. Nashville-based, MSS Inc., a division of San Diego-based recycling equipment company CP Group, can target several C&D materials from a facility’s midsized fraction. Its optical sorters can recover any of the following, according to the company:
The optical sorters use high-resolution near-infrared (NIR) and color sensors to identify materials for separation. In some cases, the optical sorters work in tandem with destoners and air classifiers to maximize recovery. Felix Hottenstein, MSS sales director, says there is great interest among C&D recycling facilities for optical sorting, but smaller facilities often cannot justify the expense. For high-volume facilities, however, optical sorting can offer huge savings and recovery.
“Wood is the area where the optical sorter would have the highest potential as far as increasing the yield at the facility and replacing manual labor,” says Hottenstein.
“However, when we looked at the midfraction, we felt that lots of wood and aggregates could still be reclaimed, so we simply added a destoner right after the magnet to take all of the aggregates out. Then we put the optical sorter after the destoner to sort the wood out.” Bourgeois adds, “The optical sorters can pick all these small wood pieces that human’s simply can’t pick.”
When Baumann’s first started operating the optical sorter, some of the older, decomposing wood caused some issues in the sorter’s ability to read the material.
“Fortunately, our engineers modified the program and, after a few tweaks here and there, were able to differentiate a true piece of wood from a contaminant covered with some decomposed wood,” says Bourgeois.
Once the initial kinks were worked out, Baumann says he noticed a difference right away in the amount of wood being recovered and the amount of labor being saved.
Instead of having seven or eight people sorting out wood, Baumann has one person quality checking the line. The destoner separates the smaller pieces of aggregate and blows the light fraction, consisting of mostly papers, off of the line, which is monitored by a single operator.
“The efficiency was the driver and being able to reduce labor,” Baumann says about why he made the investment in the new equipment. He estimates labor savings alone to be more than $140,000 per year.
Additional savings come from disposing of less material. More wood recovery also means more product and more profit.
“Whatever I don’t recycle, I have to dispose of, which obviously is a cost. My whole driver is to be able to be as efficient as I possibly can be with the products I produce,” says Baumann.
As Baumann’s Recycling Center in Cleveland improves its efficiency with the installation of an optical sorter and destoner, company President Bill Baumann says he is having some difficulties figuring out what to do with the facility’s fines and residuals.
While Baumann says he has received a grant from a section within the Ohio Department of Natural Resources (ODNR), he has not yet been given approval from the state to use fines as a base at his facility. In addition, Ohio Enviornmental Protection Agency (EPA) has indicated these materials need to be managed as municipal solid waste (MSW) rather than C&D.
According to Baumann, the agency is requiring residuals from his facility to be disposed of as a MSW because the material is considered pulverized or unidentifiable. Baumann, who says the material entered his facility as C&D and is never pulverized, characterizes the residuals as C&D waste, which is less expensive to dispose of. Baumann is waiting for an exemption for his waste, but until then, he has been hanging on to these materials.
Bruce McCoy of Ohio EPA acknowledges that finding uses for some fines or residuals at C&D recycling facilities can be challenging, especially because contaminants like lead or arsenic may be present. “We can’t just say it is soil and allow it to be disposed of as though it is,” he says. “We are hoping the industry will approach Ohio EPA with some sort of plan if it feels there is some legitimate and safe use for the pulverized material, but until we have something we can look at and consider for approval, we can’t do much with verbal requests,” says McCoy.
Since no proposals are currently on the table for beneficial use, the material needs to be properly disposed of, according to McCoy. “They can’t just speculatively accumulate it,” he says.
“It’s a terrible situation,” says Baumann, who estimates 25 percent of the material his facility produces is fines.
The author is managing editor of Construction & Demolition Recycling and can be reached at firstname.lastname@example.org.
A video showing how material is processed at Baumann’s Recycling Center is available at www.CDRecycler.com/baumanns-recycling-process-video.aspx.