August 20, 2008 | General

Airport Food Court Composting

BioCycle August 2008, Vol. 49, No. 8, p. 36
Portland International Airport (PDX) in Portland, Oregon expands its food waste collection to travelers.
Meredith Sorensen

IN November 2007, Portland International Airport (PDX) in Portland, Oregon, unveiled a set of waste receptacles in the newly renovated Concourse D that allow travelers to send leftover burgers, French fries, cookie crumbs and salads to a composting facility. Collecting clean loads of food waste from multilingual travelers who purchase food from multiple vendors was a challenge that PDX stepped up to meet through creative signs and partnerships with local tenants. Approximately 2.8 million passengers pass through PDX’s Concourse D every year. The airport, which services 14 million passengers annually, hopes to expand its food waste collection to other food courts throughout the terminal as they are renovated. Lessons learned from this project will be applied to other public area food waste collection endeavors.
The Port of Portland, a regional government agency, owns PDX. It contracts with Community Environmental Services (CES), a student-based research and service organization at Portland State University that coordinates waste reduction and recycling projects throughout the region.
The airport launched a food waste diversion program in January 2003 (see “Airport Launches Food Waste Diversion Program,” BioCycle March 2004). By the end of 2007, PDX had a well-established program with more than 20 food and beverage vendors collecting pre- and postconsumer food waste in kitchens and prep stations. Additionally, PDX had partnered with local businesses to share fixed collection costs on a food waste collection route (see “Airport Economizes On Food Residuals Collection Costs,” BioCycle August 2005). On average, PDX and its partners diverted 27 tons/month of food waste during 2007.
To further boost collection volumes, PDX built upon the systems it had already established for its food waste diversion program – a compostable bag source, special dumpsters on the airfield and a communication feedback loop with its hauler – to expand the program to include the remaining food waste generating frontier: the traveling public.
PDX considered a variety of options to best capture clean (noncontaminated) food waste from food courts. Travelers are a particularly challenging demographic. By definition, they are “on the go,” sometimes stressed and operating under time constraints as they race to catch their planes or reach their final destinations. Perhaps more importantly, they are “new” users who do not expect food waste collection at an airport. Concourse D caters to international flights with a multilingual audience. In lieu of hourly trainings, constant monitoring or busing the food court tables, PDX knew it had to develop strong, clear messaging to encourage travelers to properly sort their waste.
Initially, PDX tried to capture all compostable materials, from French fries to napkins to compostable cups. Monitoring sessions showed that the public was unable to quickly differentiate why paper French fry containers, for example, were compostable, while similar-looking paper cups (lined with plastic) were not compostable. Five food and beverage vendors operate in the food court surrounding the food waste receptacles, and each had different serviceware. It was difficult for the public to understand why one spoon (made of plastic, supplied by one vendor) went into the trash while another spoon (similar to the plastic spoon but made of corn starch) went in different containers.
It quickly became apparent, based on staggering contamination rates, that if public food waste collection was to work, the type of materials targeted for collection and the messages had to be basic. The messages on signs were shifted to “food scraps only,” resulting in an immediate decrease in contamination.
Also, PDX added messaging directly at the point of disposal. Passengers responded strongly to signs placed within a four-inch radius of the hole that clearly said, “Food Scraps Only,” and “No Foil, No Plastic,” in bold, red font.
The Grand Opening
The original container opening for food waste disposal was large and rectangular. Observations suggested that the size and shape of the opening did not facilitate collection of a noncontaminated food waste stream because it looked too much like a typical trash receptacle. The hole was an easy target for the uncaring patron. As a result, the size and shape of the opening was changed in conjunction with the upgraded, simplified messages.
While most of the focus on this project has been on changing behavior downstream, PDX is also working upstream by helping its food and beverage vendors switch to compostable serviceware. Part of that effort includes looking at changing language in the lease agreement over the next five years to strongly encourage the use of durables or compostables. The current goal is to have everything coming over the counter from food and beverage vendors be compostable, which will allow nearly all food court waste to be diverted as compostables. While some businesses face branding constraints, others have already made the switch. The airport facilitates this process by providing businesses with information on what compostable serviceware is accepted at the Cedar Grove composting facility where materials are taken, as well as which distributors sell those materials, and at what price.
PDX decided early on to line the food waste collection containers with compostable bags. However, the PDX recycling team noticed that the janitorial service exchanged bags in the food waste cans at least four times a day, and that the bags were often not being fully utilized. In order to reduce bag costs, PDX created a false, elevated bottom by placing an upside-down crate in the bottom of the food waste receptacles. A five-gallon bucket was placed on top of the crate lined with a smaller, less-expensive 13-gallon compostable bag. The janitorial service can easily lift the bag out of the bucket, transport it together with the rest of the waste and recycling, and drop it into one of the four, 4-cubic yard food waste dumpsters located beneath the terminal.
Each year, PDX becomes more savvy in its ability to collect food scraps and coffee grounds from its operations, and vendors, as shown in Table 1. Collecting food waste from travelers is just another step in expanding the program. Also, the airport has noticed a positive response from the public, which increasingly prioritizes recycling, composting and environmental efforts.
Meredith Sorensen coordinates the CES Waste Minimization Program for the Port of Portland and developed the original signs for the Terminal D Food Court. She can be contacted at For additional information, contact Sorensen or Stan Jones, aviation environmental compliance manager who coordinates the Portwide effort to reduce waste and increase recycling (

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