By Sarah Shapiro, Student in the M.S. in Sustainability Science Program, School of Professional Studies
At current estimates, about 4 to 12 million metric tons of plastic waste enter the world’s oceans each year. M.S. in Sustainability Science (SUSCI) students Emily Olin, Ngoc Truong, Tyler Zorn, Steven Wagner, Max Jin, Tzina Santos, Ryan Huber, Storm Heidinger, and Olivia Colton set out to understand and address one of the plastic sources: expanded polystyrene (EPS, more commonly referred to by the brand name Styrofoam) during the Spring 2024 Capstone Workshop course under the direction of faculty advisors Athanasios (Thanos) Bourtsalas and Beizhan Yan.
“The material is very light (more than 95% of the final product is air), making it cheap to produce and ship, but those same traits make it bad for the environment,” says Capstone team member Olivia Colton. “Its lightweight quality means EPS is inefficient to transport for recycling and takes up a disproportionate amount of space in landfills. EPS can take 500 years to break down, and that's just to break down into infinitely smaller pieces, not even biological decomposition!”
New York City banned single-use EPS in 2019, and the state followed with a ban in 2022. These policy changes substantially reduced EPS waste to less than half of the pre-ban levels. However, there is still work to be done. Though EPS-containing food packaging is banned in NYC, there is still plenty of EPS waste from shipping and packaging. Prior to the 2019 ban, there was an effort to develop city-wide curbside polystyrene recycling, but the project was scrapped because EPS is not easily recyclable. EPS waste almost entirely ends up as litter, in landfills, or is burned with other trash as a source of energy.
The New York City Department of Design and Construction (DDC), which manages the design and construction of public buildings, infrastructure, and capital projects, recognizes that EPS waste is growing environmental concern. The DDC has sought to better understand how to reduce EPS waste as part of NYC’s broader efforts to improve sustainability and lower its ecological footprint. To explore viable pathways forward, the DDC partnered with faculty and the SUSCI Capstone team to conduct a preliminary investigation.
The resulting “Expanded Polystyrene in NYC” Capstone project had three parts: an analysis of residential waste characterization data, a review of EPS-related policies, and a life cycle assessment of EPS waste.
Drawing on insights from their research, the capstone team developed a set of policy recommendations for the DDC. These included extended producer responsibility, the creation of an additional collection stream, and densification of EPS product.
The Spring 2024 Capstone team members.
Extended producer responsibility would require companies that manufacture EPS products to bear the cost of recycling them. In order to assess feasibility, the Capstone team calculated the potential costs and savings of implementing a dedicated EPS waste collection system, using either electric or biodiesel-powered collection trucks to minimize the environmental impacts associated with transporting EPS to a recycling facility. According to the analysis, a fleet of electric vehicles (EVs) have higher upfront costs in the first year due to the expense of purchasing new vehicles (an estimated cost of $3,894 per ton of EPS versus $165 per ton with biodiesel-fueled trucks). However, after the first year, the cost per ton of EPS estimated for EVs drops significantly to approximately $127. This finding also supports the city's bill: Intro. 279-A, which seeks to formalize the goal of transitioning the municipal vehicle fleet to zero-emission vehicles by 2038.
Densified EPS pellets have many end uses, including toys, furniture, and carpets. The additional collection stream would be run from collection sites at major retail stores and special Department of Sanitation sites. After conducting a net present value (NPV) financial analysis, the team found that even with low recycling rates (less than 1%), EPS recycling would be worth the cost.
“Policy action has already been very effective in reducing the amount of EPS in the waste stream,” says Colton. The report indicates that the next steps for future research involve analysis of the social cost and policy interventions that may affect the economics of waste management.
“We remain optimistic about the future of EPS,” says Capstone team member Max Jin.
To learn more, you can read their Capstone report here and watch their recorded presentation on YouTube.
Views and opinions expressed here are those of the authors, and do not necessarily reflect the official position of Columbia School of Professional Studies or Columbia University.
About the Program
The Columbia University M.S. in Sustainability Science program, offered by the School of Professional Studies in partnership with the Climate School, prepares students for management and leadership positions in which they help organizations address environmental impacts. Students learn strategies to respond to the ever-changing environment and predict future environmental changes—and the impact on corporations, not-for-profits, and the public.
Designed by Research Faculty at the Lamont-Doherty Earth Observatory in collaboration with Columbia’s Earth Institute, the program develops a new generation of scientific leaders through a cutting-edge curriculum led by the world’s top sustainability scientists, the majority of whom are Lamont Research Professors. Graduates are well prepared for management and leadership positions, armed with the scientific expertise to drive meaningful environmental change and lead organizations in a rapidly evolving sustainability landscape. With the flexibility to choose from a variety of courses, students can tailor their education to career goals, while New York City serves as a living laboratory for sustainability innovations and connects them with employers actively seeking program graduates.
