Making Waste Productive

Do you ever throw something away and think about where it will end up? Have you wondered if a piece of trash will ever serve a useful purpose again — and, if so, what form it may take?

Those are increasingly important questions because each year, the world creates about two billion tons of municipal solid waste. While roughly 20% of it is recycled, the rest goes into landfills — including everything from food packaging and leftover food to clothes and furniture to machinery and electronics and much more. Projections suggest that global annual waste will grow by 50% over the next several decades.

Complicating the issue is the fact that the world’s growing “waste problem” is not just a matter of determining where to dump 50% more trash. There is a clear need to reduce the amount of natural resources and energy used in producing replacement products; and to limit the toxic chemicals and environmental pollutants often employed in current manufacturing processes.

Jefferson researchers are helping drive that work forward. Employing materials found in garbage bins, trash dumps and fields overgrown with invasive plants, these scientists, engineers, business strategists and designers are finding innovative ways to reuse waste materials to develop greener research-and-development processes and more sustainably manufactured products.

“Reusing” Invasive Plants

Invasive plants can have an array of negative environmental effects, from harming native species to harboring ticks that transmit Lyme disease. For the past several years, Jefferson faculty and students — led by textile design researcher Becky Flax, MS, and biology researcher Anne Bower, PhD, — have been developing a novel, sustainable-reuse approach to address the problem: Harvesting invasive plants and using them to create natural, non-toxic alternatives to synthetic dyes for textiles. Their research has focused especially on two troublesome species: Japanese barberry and wineberry.

The researchers — including undergraduate students in pre-medical sciences, biology and health sciences and graduate students in textile design, textile engineering and textile technology — first harvested and processed roots of those plants, created a variety of dyes from that material, and applied them to various organic cotton and wool fabrics used in cold-weather and outdoor apparel. “We found that the dyes were effective in creating a range of attractive earth tone-colors that retained colorfastness despite perspiration and laundering,” says Flax, “They also display promising antimicrobial action against three common disease-causing bacteria.”

The research team then tested dyes created from the plant’s stems and berries. “Our goal is to use as much of the plant as possible,” explains Dr. Bower, who brings to the project her deep knowledge of the invasive plants’ biology and environmental impacts.

Those tests showed that dyes from the stems had similar efficacy to that of the root-derived dyes and resulted in similar colors. However, they found that a larger volume of berries was required to achieve the same degree of dyeing, and the berries’ acidity resulted in a range of lighter-hued, almost pastel-like colors. “The berries’ chemistry may enable us to achieve different effects with various dye formulations,” says Flax. “And excitingly, a single plant can be used to create a broad range of dye colors — from pink to brownish orange to bluish gray.”

Next, the researchers sought input from commercial dye-makers and textile manufacturers on the specific formulations and products of invasive plant-based dyes that might be most useful to them.

They learned two related lessons about the textile market: One, before adopting a novel approach to sourcing dyes, textile manufacturers will want to be assured of the supply of raw materials. Two, large-scale manufacturers will want access to large-scale harvesting of the raw materials. “That, we realized, could create an incentive for them to intentionally plant invasive species crops rather than to seek out and remove them, which is a primary objective for this project,” Dr. Bower says.

Thus, the current goals of the project are two-fold. First, the researchers have broadened the array of invasive plant species being used: Butterfly bush flower, the purple/blue flowers of which surprisingly create an orange dye; cork tree bark, which yields a vivid yellow dye; and crepe myrtle and pokeweed berries, which yield pink and purple dyes, respectively. “This allows us to increase both the range of dye colors available and the supply of raw materials,” Flax explains.

Second, the research team is targeting small, niche companies that would be satisfied with the smaller-scale harvesting that would help to eliminate existing growth of invasive plants. This would also promote small-scale economic development across the region.