Every bag of trash tells a story. In Maine, that story is now a lot clearer thanks to the state’s latest Waste Characterization Study, which takes a deep dive into what we’re throwing away, where it comes from, and what it’s costing us economically and environmentally. This study is a significant effort by the Maine Department of Environmental Protection and its collaborators, requiring the audit of many tons of waste statewide. Given the scale of the work, updated data is published every few years.
Let’s dive in to see what the latest data reveals.
The Big Picture: How Much Waste Maine Generates
Before we begin, it’s important to clarify that this Waste Characterization Study examined only materials disposed of in the trash. It did not analyze or provide a breakdown of the state’s recycling or food waste streams. While the study does reference recyclable materials and food waste, it does so solely in the context of their presence within the trash stream.
In 2023, Maine disposed of 1.3 million tons of waste, which the study divided into three categories:
- 790,942 tons of Municipal Solid Waste (MSW)
- 451,965 tons of Construction & Demolition Debris (CDD)
- 78,673 tons of Other Bulky Waste (OBW)
Of the total MSW generation, 71.7% went to landfills, while 28.3% was processed through waste-to-energy (WTE) facilities like ecomaine.
To better understand what makes up this waste, samples were collected in 2024 from 10 solid waste receiving facilities across the state including landfills, waste-to-energy plants, transfer stations, and recycling facilities. One of the chosen test sites was ecomaine’s Waste-to-Energy Facility in Portland, ME.
Where Waste Comes From
When broken down by sector, Maine’s waste stream looks like this:
- Residential Municipal Solid Waste (MSW): 22.3%
- Institutional, Commercial, and Industrial (ICI) MSW: 30%
- Construction & Demolition Debris (CDD): 47.7%
While CDD makes up nearly half of all disposed material, residential and commercial waste together still represent a massive opportunity for waste reduction and diversion.
What’s in Maine’s Trash?
Across residential and industrial (ICI) MSW statewide, two material groups dominate:
Organics: 26.7%
Paper: 26.7%
Together, they account for more than half of all MSW:
The top 10 materials by weight in MSW are:
1. Unpackaged food waste
2. Old corrugated cardboard (OCC)
3. Compostable paper
4. Packaged food waste
5. Non-recyclable resin-coated paper
6. Film and garbage bags
7. Diapers and sanitary products
8. Textiles and leather
9. Furniture and bulky items
10. Pet waste
Residential vs. Multi-Family Waste
Single-family residential trash is 30.7% organics, underscoring just how much compostable material still ends up in the garbage.
Multi-family residential waste did not differ significantly overall, but some notable (though not statistically validated) trends emerged. Multi-family waste appears to contain:
- More corrugated cardboard, glass bottles, electronics, and CDD-type materials
- Less pet waste and paper
The prevalence of recyclables and electronics in multi-family waste highlights a clear need for improved recycling access, education, and policy intervention in these settings.
Importantly, this need is already being addressed by ecomaine prior to the release of this study. In 2024, ecomaine was awarded a substantial EPA-funded grant to launch its Multi-Family Recycling Initiative (MFRI), a comprehensive effort focused specifically on improving recycling access and participation in multi-family housing. Led by ecomaine’s dedicated MFRI team, the initiative provides on-site education, infrastructure improvements, and direct support to property managers and residents. This demonstrates that targeted investment and outreach can effectively combat the challenges identified in this waste characterization study.
Waste-to-Energy Insights
Waste-to-energy facilities process a mix of waste types and the DEP study found that WTE’s waste stream approximately breaks down into:
43.1% Residential MSW
56.9% ICI MSW
To capture this complexity, the study sorted MSW into 88 distinct categories offering one of the most detailed looks at Maine’s waste stream to date.
One notable finding was that 18 tons of lithium ion batteries were identified in the MSW during the study; these items are a concern for waste facilities due to their hazardous nature and flammability. This suggests a need to modernize the existing battery collection program in Maine – a process that the DEP is already undertaking as part of their product stewardship plans. Although there was a relatively low incidence of batteries, e-waste and household hazardous waste (HHW), they were still observed, suggesting EPR programs could be revisited.
The Cost of What We Toss
The environmental and economic impacts of disposal are substantial. According to the study, Maine lost approximately $21.8 million in potential revenue in 2024 due to recyclable materials being thrown away. Beyond the financial implications, the calculated potential for reduction in emissions from materials disposed of in 2024 was estimated to be about 480,982 metric tons of CO₂ equivalent. To put that into perspective, that is comparable to the yearly emissions from approximately 104,000 to 105,000 gasoline-powered passenger vehicles. That’s a massive climate opportunity hiding in plain sight.
Key Conclusions
The study highlights several important trends:
- While CDD and MSW are often intermixed, Maine’s reliance on Waste-to-Energy (WTE) as a primary disposal method has resulted in minimal crossover between the two streams. Because CDD cannot be processed at WTE facilities, relatively little CDD enters the MSW stream, and conversely, little MSW is found in CDD loads.
- Bottle Bill materials have low disposal rates, suggesting the implementation of legislation has been successful.
- Food waste remains a major component of the waste stream and something to be addressed in the State of Maine with more efforts aimed at reduction and diversion.
- Problem materials such as batteries, e-waste, and hazardous household waste appear at low rates among residential waste, but should still be looked at due to the significant risks presented by improper disposal.
- Common recyclables are uncommon in single-family residential MSW.
- Multi-family waste contains higher levels of recyclables and electronics (though this finding is somewhat tentative, since a statistically significant number of samples were not taken).
- 3x more recyclable cardboard, by tonnage, was disposed of in the ICI MSW than in the residential MSW.
- Reporting on CDD is inconsistent statewide.
Recommendations Moving Forward
To build on these findings, the study recommends:
- Improving solid waste facility reporting
- Updating waste characterization data every 5–7 years
- Using detailed material analysis to inform Extended Producer Responsibility (EPR) program design and management
Why It Matters
This study makes one thing clear: Maine has already made progress, but there is still enormous untapped potential in reducing waste, cutting emissions, and recovering valuable materials. Better data, smarter policy, and targeted outreach, especially around food waste and multi-family recycling, could move the needle in a big way. Education is truly the foundation for lasting change. Connect with us to bring impactful programs to your schools and communities!
Our trash isn’t just something to get rid of. It’s data. And when we pay attention to it, it can help shape a more sustainable future for Maine.
Don’t miss ecomaine’s analysis of the DEP’s other recent reports:
