“Over time, this material floating in the oceans breaks into tiny pieces. It’s ingested along with plankton by aquatic animals,” Sharma emailed me.
The material in plastic shopping bags has been detected in the oceans near both the north and south poles. It’s also a problem in the Great Lakes. Because the plastic apparently takes centuries to fully degrade in nature, the issues that the bags pose are long term.
But Sharma and his colleagues have an alternative use for the bags. Once the plastic is broken down anaerobically in a lab, it yields a variety of useful chemicals including solvents, engine oils, gasoline and natural gas. The bulk of the material produced is an alternative diesel fuel — one that Sharma and his co-workers found to be a good blending component for regular diesel.
“This approach can also be applied to other low value plastics as well,” Sharma wrote to me.
I’ve often thought that there’s no single solution for pollution problems. And while turning plastic bags into diesel may only work for some bags, it’s an interesting approach to getting rid of what otherwise would be trash — while producing a valuable commodity.
Dr. E. Kirsten Peters is the author of “Planet Rock Doc.” This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University. Peters can be reached at rockdoc.wsu.edu and on Twitter @RockDocWSU.