Ninety-five percent of wooden pallets in the U.S. are being recycled instead of sent to landfills as DCs and landfill facilities increasingly choose to repair, resell, or grind up the old pallets for mulch, according to a study released March 29.

Researchers at Virginia Tech conducted the two-year survey by tracking the flow of pallets into municipal and solid waste (MSW) and construction and demolition (C&D) landfill facilities. The academics collaborated with the National Wooden Pallet & Container Association (NWPCA) and the U.S. Forest Service.

Both types of facilities have cut the number of pallets entering their landfills by 86 percent since the last measure in 1998, according to the study. This is due to factors like heightened environmental awareness, limited disposal space, and a desire to be more waste-efficient, the researchers found.

The increased recycling of pallets happens both at the industrial sites that originally receive them and at the landfills where many pallets wind up, according to study co-author Brad Gething, the NWPCA's director of science and technology integration. Workers at both types of sites stockpile the used pallets, selling those still in good shape to brokers who then repair and re-sell them. Meanwhile, the older pallets are ground up into wood chips that can be used for landscape mulch, animal bedding, or biofuel.

Between 1998 and 2016, the proportion of MSW landfill facilities performing this practice rose from 33 percent to 62 percent of facilities, and the C&D facilities increased from 27 percent to 45 percent, according to study co-author Laszlo Horvath, an assistant professor at Virginia Tech. Overall, the number of wooden pallets sent to landfills in MSW and C&D landfills dropped to 25.39 million from 178.5 million over the same period, the study found.

Another reason that recycling has increased in popularity is that brokers make it easy for warehouses and other industrial sites to participate, Horvath said in an interview. Brokers often park a trailer at a warehouse or factory, filling it with old pallets and sending a truck to pick it up about once a week, he said. They pay warehouses for the used pallets, offering prices that vary with demand. Prices range from about $1 per pallet around the Blacksburg, Va., region to $3 to $4 per pallet around Charlotte, N.C., Horvath said. The brokers then repair broken pallets and re-sell them for as much as $7 apiece, while pallets too damaged for repair are fed into a wood chipper.

One shortcoming of the pallet recycling model is that brokers typically collect used pallets only within a 100-mile radius or so, since the fuel costs required for long-distance hauls would quickly overcome their profit margin, Horvath said. Warehouses located too far from a recycler can buy their own wood chippers and sell the mulch without a middleman, but few facilities find that investment worthwhile, he said.

Another complication of pallet recycling is concern about the safety of the chemicals used to eradicate invasive insects—such as the infamous Asian long-horned beetle. However, a previous Virginia Tech study showed that those chemicals do not pose health threats in wood chips used for purposes such as landscaping mulch or animal bedding, he said. In addition, many pallet manufacturers use heat instead of chemicals, sidestepping the issue entirely, said Horvath.

The data contributes to a long-running debate between vendors of wooden pallets—which tout their low cost and recyclable materials—and vendors of plastic or metal pallets, which say the high endurance of those durable materials leads to less waste. For example, a separate Virginia Tech study released March 21 showed that a 40-by-48-inch plastic pallet sold by Orbis Corp. survived an average 200 repetitions of a material handling sequence, compared to 11 cycles for a comparable whitewood stringer pallet.