Research developments

Study finds new method of breaking down polyethylene into fuel

Chemists in China have discovered a new method of breaking down polyethylene into usable fuel in a new study published in Science Advances. Zheng Huang from the Chinese Academy of Sciences, along with his colleagues, conducted the study.

The study notes, polyethylene, a plastic commonly used to make water bottles, food packaging, plastic film and shopping bags, does not easily degrade in the environment.

In the study, the scientists added an organometallic catalyst that contains iridium that would degrade the plastic at temperatures as low as 302 degrees Fahrenheit.

The catalyst weakens the bond that creates the stiff structure of polyethylene and speeds up the process of breaking down the plastic into a liquid product that can be used as fuel, the study revealed.

“Common plastic wastes, such as postconsumer polyethylene bottles, bags, and films could be converted into valuable chemical feedstocks without any pretreatment,” a report in The Tech Times says.

While the method uses less energy than other processes because of its low temperature process, researchers note it is slow—taking about four days to complete. The catalysts are also expensive.

Scientists say they intend to scale up the process.

White paper sheds light on ‘real’ recycling rates

Bill Moore, president of Moore & Associates, an Atlanta-based consulting firm for the paper and paper recycling industry, and Peter Engel, senior consultant at Kessler Consulting Inc., a solid waste consulting firm based in Tampa, have announced the release of a white paper, “Demystifying MSW Recycling Rates.”

The white paper is was developed to shed light on what Moore and Engel say are “real” recovery rates of municipal solid waste (MSW) in the United States.

The project team says it believes this is the first study to integrate national MSW recovery rate data and distinguish between residential sectors versus industrial, commercial and institutional (ICI) sectors.

“With so much emphasis on recycling and diversion in the market right now, there is a huge amount of confusion and contradiction about recycling rates,” says Moore.

Engel adds, “A common foundation is essential for meaningful discussion and comparison among national, state and local jurisdictions. This white paper provides some clarity that should help advance the dialogue.”

Some key findings of the “Demystifying MSW Recycling Rates” study are:

• The U.S. Environmental Protection Agency (EPA) MSW recovery and disposal numbers, which are widely referenced by stakeholders, may underestimate national MSW generation and overestimate recovery.
• Comparing local government recovery rates to national statistics is rarely valid. Furthermore, the diversity of methods that state and local governments use to calculate recovery rates makes comparison amongst jurisdictions highly susceptible to misinterpretation.
• The authors estimate that 61 percent of MSW is generated by the ICI sector versus 39 percent by the residential sector.
• Estimated materials recovery is 23 percent of MSW nationally, with organics recovery adding another 5 percent, for a total of 28 percent, less than EPA’s 34 percent recovery rate.
• The authors estimate that the ICI sector recovers 30 percent of its MSW through materials recycling, while residential materials recovery is estimated to be 14 percent of MSW generated.

Engel says, “This study examines the challenge that the recycling community faces when comparing recovery data. It identifies the fundamental differences between local versus national recovery rates.”

He adds, “In particular, our facts indicate that the majority of materials recovery occurs in the ICI sector, not the residential sector, which has important implications for understanding the challenges and opportunities to achieve aggressive recovery goals.”

“Demystifying MSW Recycling Rates” concludes with recommendations for future improvement of recycling rates, and ensuring they are measured consistently across all jurisdictions.

Copies of the white paper are available by request at the Moore & Associates website, MARecycle.com, and clicking on the “Contact Us” button.