Additives Trigger Plastics Bio-Degrading, But Standards Needed
November 30, 2011
Despite efforts to encourage the recycling of plastic water bottles, milk jugs and similar containers, a majority of the plastic packaging produced each year in the United States ends up in landfills, where it can take thousands of years to degrade.
To address the problem with traditional polyethylene, polypropylene, Styrofoam and PET products, researchers at Atlanta's Georgia Institute of Technology are working with the Plastics Environmental Council to expand the use of chemical additives that cause such items to biodegrade in landfills.
Added during production of plastic packaging, the compounds encourage anaerobic landfill bacteria and fungi to break down the plastic materials and convert them to biogas methane, carbon dioxide and biogenic carbon - also known as humus. The additives - simple organic substances that build on the known structures of materials that induce polymer biodegradation - don’t affect the performance of the plastic, introduce heavy metals or other toxic chemicals, or prevent the plastic from being recycled in current channels.
If widely used, the additives could help reduce the volume of plastic waste in landfills and permit much of the hydrocarbon resource tied up in the plastic to be captured as methane, which can be burned for heating or to generate electricity.
“However, legislators, regulatory agencies and consumers need more assurance that these containers will perform as expected in actual landfills. We need to provide more information to help the public make informed buying decisions,” says Lisa Detter Hoskin, a principal research scientist in the Georgia Tech Research Institute and co-chair of PEC’s technical advisory committee.
Hoskin and other Georgia Tech researchers are working with PEC to develop a set of standards that would ensure accuracy and consistency in the determination and communication of the plastic containers’ biodegradation performance.
“This certification is intended to establish the requirements for accurate labeling of materials and products made from oil-derived plastics as anaerobically biodegradable in municipal landfill facilities," Hoskin says. "The specification, along with a certifying mark, will allow consumers, government agencies and recyclers to know that the item carrying it is both anaerobically biodegradable and recyclable.”
Full development and adoption of the new standard specification by ASTM International will likely take between 18 months and two years. Read more.