Study finds Ingeo biopolymer stable in landfills
- Filed in:
A peer-reviewed article, "Assessment of anaerobic degradation of Ingeo polylactides under accelerated landfill conditions," appearing in the journal of Polymer Degradation and Stability concludes that Ingeo™ biopolymer is essentially stable in landfills with no statistically significant quantity of methane released. This conclusion was reached after a series of tests to ASTM D5526 and D5511 standards that simulated a century’s worth of landfill conditions.
“This research is the latest in a series of NatureWorks initiatives aimed at understanding and documenting the full sustainability picture of products made from Ingeo,” says Marc Verbruggen, president and CEO, NatureWorks. “We work with a cradle-to-cradle approach to zero waste. What this means in terms of landfill diversion, for example, is ideally that Ingeo foodservice ware would be composted in order to enable the landfill diversion of a food-residual stream, and that Ingeo resins and fibers would be mechanically or chemically recycled and not landfilled. However, these systems are still emerging and developing. The reality today is that a percentage of Ingeo products end up in landfills. And now we can say with certainty that the environmental impact of that landfilling, in terms of greenhouse gas release, is not significant.”
Verbruggen added that several months ago Ingeo was the first biopolymer to receive tandem certifications for sustainable agricultural practices in growing feedstock. “NatureWorks is looking at sustainability from a 360-degree perspective—from sustainable agriculture to facilitating sustainable end-of-life scenarios for Ingeo bioplastic and fiber,” he says.
Two scenarios tested
Conditions in landfills can vary considerably by geography, management practices, and age of waste. As a result, researchers Jeffery J. Kolstad, Erwin T.H. Vink, Bruno De Wilde, and Lies Debeer of Belgium-based Organic Waste Systems performed two different series of tests spanning a broad spectrum of conditions.
The first was at 21˚ C (69.8˚ F) for 390 days at three moisture levels. The first series did not show any statistically significant generation of biogas, so the team decided to push the stress tests to a higher and more aggressive level and instituted a series of high solids anaerobic digestion tests. Today, some landfills are actively managed to act as “bioreactors” to intentionally promote microbial degradation of the waste, with collection and utilization of the byproduct gas. To capture this scenario, the second series of tests were designed to simulate high solids anaerobic digestion under optimal and significantly accelerated conditions and were performed at 35˚ C (95˚ F) for 170 days. While there was “some” biogas released in this aggressive series of tests, the amount released was not statistically significant according to the peer-reviewed research paper.
Both series of tests were designed to represent an examination of what could happen under a range of significantly accelerated anaerobic landfill conditions and were roughly equivalent to 100 years of conditions in a biologically active landfill.