You are here:
Methods for Characterization of Plastics Contamination in Food Waste from Depackaging Facilities
Citation:
Gonzalez, Michael A., David E. Meyer, D. Young, A. Foster, N. Sylvest, M. Machavaram, AND R. Venkatapathy. Methods for Characterization of Plastics Contamination in Food Waste from Depackaging Facilities. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-24/097, 2024.
Impact/Purpose:
The United States (U.S.) is committed to reducing wasted food by 50% by 2030, primarily by diverting the organic waste from landfills. Diversion occurs by promoting processes like anaerobic digestion and composting of food waste. However, contamination of food waste with plastics may complicate composting and anaerobic digestion operations. First, some plastics can inhibit performance of these operations and even lead to increased production of unwanted greenhouse gases. Even if the plastics can be processed, the occurrence of micro- and nanoscale plastic fragments can decrease the market desirability and safety of land application of the compost and digestate and reduce the economic viability of these processes. Since the plastics are most often associated with packaging and containers, large food waste processors are increasingly implementing depackaging technologies as a primary means of removing the plastics contamination. Since depackaging equipment is still evolving and microplastics has become topic of significant importance globally, there are research questions surrounding the effects of these machines on plastics in the organic waste stream. To evaluate some of these questions, food waste samples were collected from organics processing facilities around the U.S. and analyzed in a U.S. Environmental Protection Agency (EPA) laboratory. Samples were freeze dried, digested, and analyzed using stereomicroscopes, Fourier Transform Infrared Attenuated Total Reflectance (FTIR ATR) spectroscopy, thermogravimetric analysis (TGA), and pyrolysis gas chromatography/mass spectroscopy (Py-GCMS). For microscopy, FTIR, and TGA analyses, samples had to be digested to remove organic interferences prior to analysis. Since the time required to digest samples to remove organics is lengthy, both digested and undigested samples were analyzed using a Py-GCMS to determine the effect of digestion on identification of polymers/plastics in food waste streams. The plastic polymers identified through the analysis of the food waste samples collected from the “clean” streams of the eight facilities include polyethylene, polypropylene, polycarbonate, and polystyrene. This finding indicates that while depackaging machines are very good at removing organic material from packaged food waste and diverting vast quantities of organic waste away from landfills, plastics and polymers can remain after the depackaging process. As industry and communities make further improvements in removing plastics from food waste streams, there are still key challenges when considering the goal of eliminating residual plastics in food waste to limit the formation of microplastics and nanoplastics and their spread in the environment.
Description:
This product will test the performance of de-packaging equipment available on the market in real-world settings. The U.S. is committed to reducing food waste by 50% by 2030. To divert food waste from landfills, OLEM promotes anaerobic digestion and composting of food waste; however, contamination of food waste with packaging (including film plastics) may complicate composting and anaerobic digestion operations and decrease the market desirability and safety of land application of the compost and digestate made from food waste. De-packaging technologies (beyond screens and filters) are increasingly being used by large food waste generators and treatment facilities as primary means of removing plastics. Research will characterize the plastics, including quantity and particle size, in food waste streams before and after the use of de-packaging technologies. The results from this study will be useful to OLEM, restaurant and commercial kitchen operators, food retailers, composters, and wastewater treatment facility staff across the U.S. as they seek to exclude plastics (including microplastics) from the food waste stream.