Sporting venues interested in reducing GHG emissions, energy use, and trips to the landfill may actually be shortchanging themselves by focusing too closely on the concept of reaching "zero waste," according to researchers at the University of Missouri (Mizzou). Rather, two specific aspects of waste reduction seem to far outweigh the rest in terms of reducing emissions or energy use: eliminating edible food waste, and recycling.
Researchers conducted a study to characterize the waste produced at sporting events prior to game day and unsold food disposed of on game day, quantify the greenhouse gases produced, and identify waste management and recycling strategies. Eleven waste management strategies were evaluated using the Waste Reduction Model (WARM) and researchers found that achieving zero waste - commonly understood as diverting 90% of waste from landfills by reusing, recycling, composting, etc. - may not be the thing that is most effective in terms of reducing GHG emissions or energy use. In fact, the two most effective approaches, according to the study, were found to be eliminating edible food waste and recycling.
While it seems intuitive that landfill diversion is environmentally preferable, it is important to quantitatively evaluate alternative management options against specific metrics associated with achieving greater sustainability, the report says. In other words, assuming that recycling and composting are the only or the best options should not be a foregone conclusion, researchers wrote.
Sporting venues - whether new or existing - are increasingly striving toward sustainability. Sports leagues on both the professional and college level are adopting water conservation efforts, energy reduction initiatives, recycling programs, food reduction efforts, and more, and several have announced zero-waste goals. In addition to potential cost savings from these efforts in terms of reducing operations costs, such initiatives can be useful PR for a team, the study pointed out. "Athletic events offer a great opportunity for engaging with a large, diverse audience that may not be familiar with sustainability issues and can generate pro-environmental public relations messaging to a broad audience at relatively low cost," the report states.
But Mizzou researchers felt more work was required to investigate the technical factors associated with "greening" a venue, including waste auditing procedures, quantitative evaluations of waste management options, and operational issues associated with the event.
The research team audited the landfill-destined waste generated at Mizzou’s Memorial Stadium at five home football games game in 2014. Team members counted garbage bags disposed of during and after the games and sorted representative sample bags, which were inventoried to identify the contents.
An estimated 47.3 metric tons (mt) of waste was generated. The majority (29.6 mt waste) came from off-site, pre-game food preparation activities, of which over 96% was pre-consumer and unsold food waste. The remaining 17.7 mt originated from inside the stadium; recyclable materials accounting for 43%, followed by food waste, 24%.
"The two most effective approaches are eliminating edible food waste and recycling. Source reduction of edible food reduced GHGs by 103.1 mt (carbon dioxide equivalents) CO2e and generated energy savings of 448.5 GJ compared to the baseline. Perfect recycling would result in a reduction of 25.4 mt CO2e and 243.7 GJ compared to the baseline."
Some of the study's recommendations seem relatively straightforward. Researchers suggest donating unsold food to local charities and food banks, and providing more recycling stations and receptacles throughout the stadium. They also suggest "replacing foods and preparations that are involved in higher greenhouse emissions, such as beef, with more vegetables and chicken."
But the two recommendations that were found to have the most benefits in terms of GHG reductions - "perfect" recycling, and eliminating edible food waste - require more work. Reducing the amount of food prepared can be tricky because of the difficulties in predicting demand, while influencing consumer behavior in terms of recycling has always been a challenge, the study acknowledges.
The study, Achieving Sustainability beyond Zero Waste, was funded by The Mizzou Advantage, an initiative that fosters interdisciplinary collaboration among faculty, staff, students and external partners on topics that include sustainable energy.
