Researchers at Stony Brook University’s Waste Data and Analysis Center are conducting a detailed study of municipal solid waste across New York State to improve recycling rates and inform waste management policy. The initiative comes as recycling rates in the state have stagnated, prompting closer examination of what residents are discarding and attempting to recycle.
The project is funded by an $8 million investment from the New York State Department of Environmental Conservation and is part of a 10-year effort that began in 2019. Each year, the research team sorts waste at about 20 locations statewide, excluding direct sampling in New York City but incorporating its data into broader analyses. On Long Island, the team has worked in six municipalities across Nassau and Suffolk counties.
“We want to identify what materials are being thrown away in the municipal solid waste and recyclable stream,” said Krista Thyberg, research assistant professor in the Department of Technology and Society and associate director of the Waste Data and Analysis Center. “Are the materials that are recycled acceptable materials, or are there contaminants in there that are not recyclable?”
Thyberg explained that trained samplers visit facilities throughout New York State to hand sort samples weighing about 200 pounds each for three to five days at each site. This process occurs year-round to account for seasonal variations in waste patterns. The sorted waste is divided into 69 categories, including different types of paper, food waste, and plastic containers.
“It’s a messy job,” Thyberg said, “but that level of detail is what allows us to really understand what is being disposed of and recycled.”
The findings indicate that while paper recyclables are generally well sorted by residents, there is widespread confusion regarding container recycling. At Long Island facilities, roughly one third of glass, metal, and plastic items placed in recycling bins were found to be non-recyclable.
“What we’re finding is that the paper recyclables are pretty well sorted,” Thyberg said. “Residents are doing a great job there. But the containers are much more confusing, and that’s where we see a lot of contamination.”
Plastic containers pose particular challenges due to confusing labeling systems that lead people to believe more items can be recycled than actually accepted by programs.
Based on data from 2023, nearly 18 million tons of waste were disposed of statewide within a single year. On Long Island specifically, residents recycle only about 30% to 60% of potentially recyclable material.
“If we did better, if we recycled everything we could, we would triple our recycling,” said David Tonjes, former director of the Waste Data and Analysis Center who led much of this work before retiring.
The closure of Long Island’s largest landfill adds urgency to improving recycling efforts as communities seek ways to conserve resources and reduce environmental impact.
Elizabeth Hewitt, associate professor in the Department of Technology and Society and current director of the center noted: “What makes this work especially important is that municipalities get access to rigorous, empirical data. Many local governments simply don’t have the resources to conduct this kind of research on their own, and that data is essential for making smart waste management decisions.”
In addition to supporting policy development with new data insights, the project serves as hands-on training for students involved at every stage—from planning through fieldwork and analysis—under guidance from faculty such as Thyberg; Sampling Research Manager Firman Firmansyah; Sampling Program Manager Yiyi Wang; Associate Professor Ruwen Qin; as well as Hewitt herself.
“They’re getting hands-on experience doing research from start to finish,” Thyberg said. “They help plan and prepare for the sampling, collect the data, analyze it and see how it gets reported back to municipalities and the state.” For Wang: “Conducting hands-on waste sampling across New York State and analyzing real-world data showed me how critical applied research is to improving waste management systems.” Firmansyah added: “We all generate waste, but few of us track what we throw away. This project showed me that to effectively reduce what we send to landfills, we must first be mindful of what we discard.”
The grant also enabled development of tools such as cost modeling software for evaluating new recycling options as well as assessments examining technological advances at facilities both within New York State and nationally.
Thyberg joined Stony Brook’s team shortly after funding was secured in 2020: “I came on to help get the project running,” she said. “After David Tonjes retired I took on a larger role—and now we’re focused on continuing the work he started helping communities improve recycling efforts and waste less.”
