Park benches of the future could be made from computers of the past.

Scientists in China have developed a new recycling method that makes a strong construction material out of printed circuit boards (PCBs), which had been thought to be worthless.

As more electrical and electronic equipment has become obsolete, the issue of electronic-waste removal has intensified, say Zhenming Xu at Shanghai Jiao Tong University and colleagues. PCBs account for about 3 percent by weight of all electronic waste, Xu says.

Although metals from the circuit boards, such as copper and aluminum, are recycled, landfill disposal has been the primary method for treating their nonmetallic materials, which have been difficult to recycle, the paper says.

The new process pulverizes the non-metallic parts of the circuit boards, adds a little resin, then hot presses them into useable plates.

Being almost as strong as reinforced concrete, the recycled material makes a good substitute for wood the researchers write in the July 15 issue of Environmental Science & Technology. It could be used to make sewer grates, fences and park benches.

"There is no doubt that the technique has potential in the industry for recycling nonmetallic materials of PCBs," Xu said.