What does the Department of Defense do with scrap wood, cardboard, and paper? Usually, just send them to the landfill. But these seemingly small portions of waste materials do add up—to about 13 pounds per soldier each day. According to the US Army Corps of Engineers, these comprise around 80 percent of all solid waste made at DoD forward operating bases.
Now, DARPA, a Pentagon agency that focuses on innovation and research, wants to take that waste and divert it from the landfills or burial by turning it into something useful. Through a new program called Waste Upcycling for Defense (WUD), they want to find ways to integrate scrap wood, cardboard, paper, and other cellulose-derived matter into building materials. Scientifically speaking, this is not a new idea. Various teams of researchers have been testing out this process for years.
The basics of the formula is as follows: You need to chemically treat the scraps to degrade a wood component called lignin, then mechanically press them together to make them more dense, strong, and durable against bad weather, water, and fire. In some instances, these made-again wood products are stronger than the original wood itself. And as attention around climate change focuses on the sustainability of the construction industry, there are increasing efforts to reduce emissions and experiment with greener materials, like green cement and maybe even fungi.
Although small batches of products have been made with this technique at a laboratory scale with harvested wood, these methods have not been tested on scraps, so may need to be adjusted or refined. Ideally, researchers would come up with a solution that can be scaled up for mass production.
“Finished products could greatly reduce the need for re-supply of traditional wood products, such as harvested lumber used in DoD construction and logistics,” WUD program manager, Catherine Campbell said in a press release.
DARPA aims to develop and test products and methods through a feasibility stage in the next 24 months. At the eight-month-mark, they hope to be able to start conducting mechanical property testing for the samples to figure out ways to reduce chemical and energy consumption in the process. Near the 21-month-mark is when full demos are expected to be ready to be presented to DARPA. The end goal of the Phase I period is to have a preliminary design for a device that can produce densified wood from wood waste at the rate of 100 kg/hr.
There is an accompanying callout for participation from the scientific community in this effort. Proposals are due by mid-September this year.