Overcoming ongoing challenges in C&D
End Markets for C&D wood and fines are focus of promising CDRA research
Like most other recycling market sectors, the construction and demolition (C&D) recycling industry had a challenging time with end markets in 2019. It is a reality that is expected to continue in 2020. But unlike curbside recycling, the challenges in C&D were for the most part not caused by China's import policy actions. Instead, a variety of factors impacted the recycling of concrete, wood, drywall, asphalt shingles, fines and other materials from the construction sector.
Probably two of the biggest concerns currently are C&D wood and C&D fines. Wood is facing challenges as many power-generating facilities are changing over from biomass to cheaper natural gas for fuel. This has left a glut of recovered C&D wood on the market, and there is only so much mulch a recycler can make. In addition, C&D fines, which are the smaller screened material left over from the processing of C&D materials, is also currently in abundance. The most common end market for fines has been alternative daily cover (ADC) for landfills, but if not used properly, hydrogen sulfide gas (which smells like rotten eggs) can develop. This can provide landfill operators with headaches caused by complaints from nearby residents.
Together these two materials have presented major challenges for mixed C&D recyclers. But now, in an innovative research project funded by the Construction & Demolition Recycling Association (CDRA), the University of Florida has developed proof of concept that mixing C&D fines with biochar made from wood, including C&D wood, will reduce or even eliminate the noxious smell that can develop in landfills using those fines as ADC.
Also currently, the CDRA is funding further research to provide the data regulators need to approve the mix in landfills. Once completed, this project will help C&D recyclers by "killing two birds with one stone," providing end markets for both wood and fines.
Recycled asphalt shingles (RAS) have also faced challenges in the recycling sector. A few miscues by asphalt plants using recycled shingles in their mixes have caused cracking in some highways using their modified asphalt. This is most likely because too much recycled shingle was used in the mix. With respect to RAS for modified asphalt, the more you use, the more money you save - unless the road fails, of course.
The CDRA is recommending that no more than three percent recycled shingles be used for any high-end asphalt uses, such as roads. In addition, the association is developing a paper on a promising new market for RAS - for use as dust control on gravel roads.
Drywall is another construction product that many, from green builders to government officials, want to see recycled. This ubiquitous material is another cause of the rotten egg smell in landfills. With drywall, though its recycling has increased, government officials still do not understand how it is recycled, nor how to properly regulate it.
The CDRA also recently developed a protocol for recycling gypsum wallboard, available to members and government officials.
We are working on all of these projects currently because of feedback received at our last Annual Meeting, in March 2019, held in Brooklyn, New York. At the meeting, attendees were polled on the biggest issues facing the C&D recycling industry. What came up consistently as priorities included: handling government regulations and finding end markets. For the former, the CDRA has been working on the government policy front the entire 25 years of its existence, and will continue to do so for the foreseeable future. Working on building end markets is a newer endeavor, and is an area we are increasingly focused on.
I suggest all recyclers consider coming to the 2020 CDRA meeting, March 11 in Las Vegas, registration for which includes a badge for entry into ConExpo-Con/Agg 2020. For more information on the event and our efforts, visit www.cdrecycling.org.
Terry Weaver is president of USA Gypsum, based in Denver, Pennsylvania, and president of the Construction & Demolition Recycling Association (CDRA).
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