Optimal conditions

In construction and demolition (C&D) recycling facilities, optimizing operations can help increase material flow—and pay big dividends when it comes to throughput, quality and uptime.

Plant optimization starts from the outset of the recycling process, says Remi Valdron, general manager at New Brunswick-based equipment supplier Sparta Manufacturing Inc. He often works with plant operators to optimize operations.

“My first recommendation every time I go onto a site is always to make sure that you’ve got a good presorting system,” Valdron says.

Whether done by hand or using grapples, presorting can improve flow by removing materials that shouldn’t go into the system, he says.

If an operation is not preshredding, Valdron says some materials could damage the system, while others could be too large or heavy for workers to sort by hand.

Another tool to optimize operations across the plant is magnets. Operators running a line that splits materials into fractions of different sizes should not hesitate to put magnets on all of those lines, Valdron says. “A magnet will pay for itself within a few months.”

As labor becomes harder to find, operators are seeking to optimize sorting with the help of automation and other technology, Valdron says. The newest trends he is seeing in plant optimization include:

• Preshredders—A preshredding process provides more uniformity among materials, Valdron says, and typically can reduce materials to a size of 36 inches or smaller. It can be difficult to pick very bulky materials, but if everything is preshredded, it’s easier to pick and to mechanically sort. Additionally, preshredding makes it possible to separate materials in various ways afterward, for instance by size or by form.

“There are more and more people that are now separating material by 2D versus 3D, similar to what they’re doing in the single-stream industry,” Valdron says. “You’ll have one stream that’s really wood-heavy and another stream that’s going to be heavy on cardboard, plastics and other things that aren’t as recyclable.”

• Optical sorting—Sparta has been seeing more requests for optical sorting technology. The technology has improved to a point where it’s now viable for operators to use it for quality control on wood lines, Valdron says.

“Depending on where you’re at, there are different qualities of woods that can be accepted for different markets,” he adds.

• Paddle depacking—The Mavitec Paddle Depacker, a fairly new offering repped by Sparta, is designed primarily to separate packaging from organic material. However, it has been tested on drywall, and Valdron says it’s doing an excellent job of separating plaster from paper backing and other compounds—an essential step for C&D recyclers hoping to recycle drywall, Valdron says, as no end market exists for drywall that’s not separated.

“It’s a newer technology we are seeing [and] not that expensive,” Valdron says. “It’s allowing people to recycle a material that, in the past, wasn’t recyclable a whole lot.”

Plant Optimization Case Studies

At this year’s C&D World Conference & Exhibition, three C&D recycling operators shared the unique ways they are optimizing operations at their plants, located in different regions across the U.S.

Case Study No. 1

The facility: ReSource Waste Services, Epping, New Hampshire

The challenge: Lackluster metals recovery rates

The solution: ReSource has operations across New England, including four C&D processing operations that manage about 600,000 tons of C&D material each year, as well as a rail operation.

“Our forte is to be creative, innovative in the industry. We’re really into designing and creating our own equipment and doing a lot of our buildouts,” said Vice President of Operations David DeVito, whose company has its own designers and an AutoCAD system.

Some of the in-house designed systems ReSource has integrated include bar-coded cart systems for sorting, an innovative ticketed weighing system and a creative system that keeps water flowing in subzero winter temperatures.

For DeVito, it’s all about finding new uses for existing equipment. Where ReSource has refined its process the most over the years is working to improve ferrous and nonferrous recovery.

DeVito said he has incorporated as many as 12 different screens in each operation, including action screens, triple-deck screens and even some screens originally designed and set up for the aggregate industry. Using those aggregate screens with lightweight C&D materials has proved quite successful in improving recovery rates across the board.

DeVito brings an enterprising approach to optimization. “We try and fail and see and get back up,” he said.

Case Study No. 2

The facility: van der Linde Recycling, Troy, Virginia

The challenge: Dust issues throughout the C&D processing facility

The solution: Located outside of Charlottesville, Virginia, van der Linde Recycling owns a roll-off company that feeds a C&D processing facility, as well as a rock crushing operation and a green waste facility. “Our system is about 16 years old, and there’s a lot of innovation that has come around since we initially put it in,” CEO Andrea Johnson said.

Before investing in any new equipment, Johnson likes to visit other facilities that are using similar machinery. Seeing the equipment in action and getting feedback on how it works can help operators make more informed purchasing decisions, she explained.

One change she plans to make after visiting other plants is to rearrange equipment to help with dust control. “Our trommel is really far into our process. I’ve seen other facilities where they’re getting the fines out at the beginning, and then they have a fraction of the dust issues that we have because it’s not making dust the whole way,” Johnson said.

Optimization is a constant ongoing process, she added. “As soon as we think we have it, we slip back. And it’s always a challenge.”

Case Study No. 3

The facility: Richard S. Burns & Co., Philadelphia

The challenge: Contamination in end products

The solution: Richard S. Burns & Co. runs a transfer station and a 13-acre processing facility concentrating on new construction material, processing concrete, wood and other C&D materials. “We mostly focus on sorting and coming up with innovative ways to bring a cleaner product to the end market,” said owner Allen Burns.

The company’s innovative approach to producing cleaner outbound materials often includes building its own equipment. “I’m a minimalist,” he said. “I don’t want something that’s a lot of maintenance. I want something that’s simple, that’s easy to use, that’s off-the-shelf.”

To preserve materials and create cleaner end products, what Burns came up with is a ground sorting system using wheelbarrow-like bins and Tommy Carts, the company’s own invention, with tracking technology. Contractors place materials into carts and bring them back themselves, which means the only other person touching the materials is the sorter on the line, drastically decreasing the opportunity for contamination.

The author is managing editor for Construction & Demolition Recycling magazine and can be reached via email at smann@gie.net.