After concrete, wood waste is the second largest component of construction and demolition debris (C&D). Wood waste contributes between 20 and 30 percent to the total building-related C&D. Wood accounts for about 10 percent of all materials that are deposited annually in landfills.
This is a worrying statistic for policymakers who note that the recycling rate of C&D derived timber is significantly lower than other C&D materials like concrete and structural steel. According to the Construction Materials Recycling Association, concrete recycling rates are around 82 percent and structural steel recycling rates are about 98 percent according to The Steel Recycling Institute.
Wood waste flows from C&D and municipal activity
In the United States, 70.6 million tons were generated from urban wood waste in 2010. This included 48 percent of municipal solid waste and 52 per cent from construction and demolition (C&D). The Construction Materials Recycling Association had estimated that another 29 million tons of wood waste was available for recovery in the United States. This included 48 percent from municipal solid waste and 52 percent from construction and demolition (C&D) materials. CMRA doesn’t have a current estimate, but it does note that recycling activities in the industry have increased rapidly since then.
C&D wood waste is the most prolific, at 36.4 millions tons per year. 29.7 million tons are derived from demolition and 6.7 million from construction. A U.K. study found that about 10% to 15% of wood used in new construction is recycled or disposed of.
How wood waste from C&D can be recovered
C&D wood waste is usually delivered to wood waste recycling facilities for processing. However, there is a small market for salvaged timbers and boards as well as other components.
Wood Recycling Facilities
Mixed C&D processing plants receive most C&D-related wood. Depending on the material type, the material may first be sorted using heavy equipment like front-end loaders and excavators before being fed into an in-feed system. Large pieces of wood debris may require bulk reduction equipment, such as compactors or hydraulic shears to reduce the material size so it can be inducted into a wood grinding system.
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Other features of conveyor systems include the ability to further sort foreign materials, such as ferrous metals, before they enter the grinding machine. The product can be sold after it has been screened to the required size for the particular fiber.
Although the volume of lumber being recycled and repurposed is small, their popularity is growing rapidly. Homeowners and architects are increasingly interested in reclaimed wood. Recovered lumber is often more expensive than other recycled materials due to the amount of labor required to deconstruct and further process to remove old nails or re-machine.
Markets for Recycled Wood
There are many markets for recycled wood, such as landscaping mulch, bedding material and boiler fuel. Fiber for composite board products includes Presswood pallets and pellets.