Results of a 6-phase study confirmed that compostable foodservice packaging can be effectively used as a feedstock in commercial composting facilities. The testing, funded by the Foodservice Packaging Institute (FPI), Falls Church, Va., and the Biodegradable Products Institute (BPI), New York, showed that foodservice packaging performed as well as wood and other traditional feedstocks.

“While the compostable packaging industry believed that these items had value to composting operations beyond diversion of food waste, there was little data to support this,” says Rhodes Yepsen, executive director of BPI. “The goal of this study was to determine the impact a large volume of compostable foodservice items would have on the composting process, when compared to traditional compost inputs like yard trimmings, straw, wood shavings and grass.”

The study’s six phases included foodservice selection and analysis; feedstock preparation; pre-process sampling and analysis; active composting and monitoring; post-process sampling and analysis; and reporting and peer review. The Compost Manufacturing Alliance, Port Orchard, Wash., conducted operational field tests at two commercial composting facilities. Each test included two control samples using the facilities’ standard composting mix and two samples using compostable foodservice packaging in place of the facilities’ customary bulking agents and carbon sources.

An independent laboratory tested and analyzed the samples throughout the active composting process using Test Method for the Examination of Composting and Compost procedures to determine if there was any noticeable effect from the compostable foodservice items. After processing, the finished compost samples were tested for pertinent compost characteristics, including pH, nutrient content, organic matter and moisture content. The report and its findings were then reviewed by industry experts, including CMA members and representatives from the United States Composting Council, Reston, Va., and BioCycle Magazine, Emmaus, Pa.

The results of the analyses performed before, during and after active composting provide evidence that compostable foodservice packaging provides the same benefit as traditional feedstocks, and did not affect the balance of carbon to nitrogen ratios, nutrient levels, moisture content or porosity to feedstocks or finished compost.

“Compostable foodservice packaging did not add or take away any nutrient value from the finished product,” says Susan Thoman, principal and managing director, the Compost Manufacturing Alliance. “Given these findings, compost manufacturers may want to consider compostable foodservice packaging as a viable feedstock, particularly in areas where composters may incur significant costs to source carbon-bearing feedstocks due to seasonally scarce materials.”

“We are encouraged by these results and are pleased to share them with the composting community,” says Lynn Dyer, president of FPI. “Knowing that compostable foodservice packaging not only helps supply desirable food scraps to composters, but can also reduce the amount of supplemental feedstocks composters must collect or source is a major benefit.”