In the 1980s and 1990s, a band named Dumpster Juice was playing hardcore punk and grunge music for fans in the Upper Midwest. This band’s name, as well as the bars it frequented, evokes a vivid image and odor of the stagnant, foul liquid accumulating at the base of the dumpster metal container behind a college apartment. During the same time period, landfills that collected trash from dumpsters were required to have lining systems in place, facilitating the collection of leachate — or dumpster juice on a grander scale.
Today, approximately 300 million tons of municipal solid waste are generated annually in the United States, with roughly half of it deposited in more than 1,200 lined sanitary landfills. The liquid collected at the bottom contains the mobile chemicals, leached by precipitation, from the varied residential, commercial and industrial waste.
One of those chemicals is PFAS — per- and polyfluoroalkyl substances — labeled an emerging contaminant by the Environmental Protection Agency (EPA), has long been used in industrial and consumer products like carpeting, clothing, and food packaging. Manufacturers have used PFAS to engineer products to be more resistant to grease, stains, food and water. They persist in the environment and accumulate in the body over time. Studies link PFAS exposure to health risks including elevated cholesterol, hormonal disruptions, fertility issues and increased cancer risk.
Regulatory Horizon
Several U.S. states, especially those with higher incidences of PFAS manufacturing or use in commercial production, have taken proactive regulatory measures by implementing rules and standards governing the sale of PFAS-containing products and the regulation of PFAS-containing waste.
In February 2024, the EPA introduced regulations to revise the definition of hazardous waste under the Resource Conservation and Recovery Act (RCRA), and to list nine specific PFAS compounds as hazardous constituents. Additionally, the EPA has proposed drinking water standards, or Maximum Contaminant Levels (MCLs), targeting select PFAS compounds.
Financial Implications for Landfills
To date, most landfills have traditionally partnered with wastewater treatment plants (WWTPs) for leachate disposal, prioritizing human health protection. In instances where leachate isn't applied on land or incinerated, WWTP biosolids have been disposed in landfills. Both landfills and WWTPs play vital roles in safeguarding human health by effectively managing waste that could pose health risks. In its 2021 PFAS Roadmap, the EPA designated landfills as the preferred technology for disposing of solid waste containing PFAS.
However, the proposed state and federal regulations carry significant liabilities and consequences for landfills to monitor and clean up the impacts of these chemicals at levels in the low parts per trillion. WWTPs are beginning to refuse leachate containing PFAS. According to a May 2023 report by the Minnesota Pollution Control Agency (MPCA), the cost of removing and disposing of PFAS from landfill leachate in Minnesota is estimated at around $105 million. Landfills have not generated this PFAS-containing waste, nor have they profited from PFAS manufacturing; rather, they serve as passive recipients of the waste disposed by individuals and businesses.
Leachate Treatment Challenges and Options
Landfill leachate is one of the most complex wastewaters to treat. With a diverse array of items discarded in landfills, concentrations of contaminants — including organics, dissolved solids, metals, volatile organics and PFAS — can range from parts per million to parts per trillion. The magnitude of landfill leachate flow can vary depending on weather conditions, time of year and landfill development phase. Addressing the dynamic quantity and quality of leachate requires treatment methods capable of consistently achieving low and defined concentrations to meet regulatory standards.
Treatment options for PFAS in leachate include separation, concentration and destruction technologies. Conventional methods such as membrane filtration, evaporation, ion exchange, and carbon adsorption are employed for separating and concentrating PFAS. Emerging processes include foam fractionation, supercritical water oxidation, electrochemical oxidation, photochemical methods and deep well injection, among others.
Treatment options, with their distinct advantages and disadvantages, should also focus on the following:
- Is pretreatment necessary to meet the parts-per-trillion requirements?
- Will treatment necessitate multiple processes in a treatment train?
- Is the method scalable, repeatable, and adaptable to volume and concentration fluctuations?
- What are the capital and operational/maintenance costs?
- How are residuals like spent media or concentrate managed? Is PFAS treatment possible?
- Can landfill operations be adjusted to minimize leachate generation?
- Will wastewater treatment plants continue to accept treated leachate?
A Proactive Approach
Each landfill has its own unique circumstances, requiring a tailored approach to answer these questions and deliver an effective solution. Owners and operators stand to gain from conducting a comprehensive feasibility study and potentially piloting select treatment technologies to pinpoint the most suitable treatment solution for each landfill. A proactive study should take into account evolving regulatory frameworks, partnerships with wastewater treatment plants, landfill design, leachate management, PFAS treatment technology and financial considerations. Such a feasibility study can pave the way for success, enabling landfills to navigate regulatory challenges and offering disposal options for facilities.
Uncertainty looms over waste management providers, municipalities, water utilities and manufacturers as emerging contaminants disrupt industries and communities alike. Leveraging regulatory compliance strategies and proven remediation technologies, businesses and communities can mitigate the impacts of PFAS, 1,4-dioxane, or other emerging contaminants.
