How sorting technologies are changing the business of C&D Recycling
CONSTRUCTION & DEMOLITION RECYCLING, MARCH – APRIL 2020
by Howard Fiedler, VP of Sales at Sparta.
C&D recycling systems have evolved slowly but steadily over the years. When you consider the materials generated from demoed buildings, renovations and new construction, it is easy to appreciate what it takes for a sorting system to separate out constituent materials of value while minimizing the associated residual wastes destined for the landfill.
A RECENT HISTORY OF INNOVATION
The challenge has always been how to get C&D recycling equipment to do more, so people could do less. Adding a low-speed shredder at the front end of the system was a big step in the right direction for many in the industry, as it helped regulate the size and flow of a waste stream that is by nature, a hodgepodge of contrasts—big vs. small, heavy vs. light and valuable vs. costly to dispose.
Those running systems without shredders commonly added steel Z-pan apron feeders to help provide a metered, more uniform flow to downstream equipment and workers. These systems’ low feed heights enabled excavator operators to better see and control the material mix and flow going to the screen(s).
Over time, the single line systems morphed into dual line C&D systems. Here, the “B line” was added to mechanically capture the small- and medium-size metals and aggregates that would have previously been easily missed by human hands. This addition helped impact the dual line system’s overall recovery rates and increased profitability.
The conventional wisdom has always been “the more magnets the better.” Similarly, density separators on B lines have become equally as ubiquitous, as they mechanically recover aggregates ranging from the size of a finger to the size of a head, efficiently separating by density in the process. As landfill tip rates are typically based on weight, keeping heavy aggregates out of the residuals directly impacts recyclers’ bottom lines.