Headlines nationwide underscore an imminent need for improved solutions to manage sewage sludge. Across the country, reports are drawing attention to the environmental and health crisis attributed to the incomplete processing of sewage sludge. Among the most troubling contaminants in sewage sludge are Per- and Polyfluoroalkyl Substances (PFAS), referred to as “forever chemicals” due to their nearly unbreakable carbon-fluorine bonds. Public awareness of the devastating effects of PFAS grew after the 2019 film Dark Waters, which dramatized a lawyer’s battle against a chemical company’s PFAS pollution.
For more than a century, sewage sludge treatment methods, such as anaerobic digestion, have reliably reduced pathogens, captured energy from digester gas, and produced biosolids for soil enrichment. Yet, these legacy processes are unable to break down inorganic contaminants in sewage sludge, such as PFAS, which have accumulated over time in soils, groundwater, crops, and food supplies – creating long-term, escalating risks to both human health and the environment. While wastewater agencies do not create PFAS, they will soon be held responsible under the Clean Water Act for managing these compounds, making this one of the industry’s most significant challenges.
Gate 5’s Innovative Solution
Gate 5 Energy Partners, Inc., headquartered in Irvine, California, has developed a patented thermal waste-to-energy process that can destroy PFAS and other persistent inorganic pollutants in sewage sludge. Gate 5 Infrastructure combusts biofuel produced from raw sludge onsite at high enough temperatures to break the chemical bonds in PFAS and other inorganic residuals, ensuring their destruction. The Gate 5 process converts sewage into 100% safe and usable products: renewable energy, clean water, and sustainable building materials. By eliminating biosolids production and the need for its hauling and disposal, Gate 5 Infrastructure provides financial and operational benefits to wastewater agencies, as well as greater protection for the communities they serve.
The Risks of PFAS in Biosolids
Biosolids contaminated with PFAS are increasingly scrutinized. Peer-reviewed scientific studies have found that when biosolids are applied as fertilizer, PFAS can migrate into soil, groundwater, and crops, leading to elevated health risks, including birth defects and cancer. Legacy treatment processes, even when coupled with advanced pretreatment methods that are effective against pollutants such as DDT and PCBs, cannot destroy PFAS in sludge.
Public concern and regulatory pressure are rising:
- Biosolids contain PFAS as well as other non-biodegradable compounds of concern
- Farmers are becoming hesitant to continue using sludge-based fertilizers.
- The EPA has issued warnings about PFAS health risks near biosolids-applied farms.
- Lawsuits target the EPA for inadequate PFAS oversight.
- Maine and Connecticut have banned sludge-derived products altogether.
- Many states are considering strict limits or banning the use of biosolids containing PFAS.
How Gate 5 Infrastructure Works
- Screening & Dewatering: Advanced membranes separate solids from sludge.
- Drying: A rapid flash dryer produces high-energy biofuel.
- Combustion: High-heat combustion to destroy PFAS with combusted biofuel
- Power Generation: The system is sustainable and able to produce enough energy to run the process, with surplus for on-site use or sale.
Key Benefits
- Generates renewable energy and reduces operating costs
- Can break chemical bonds of inorganic residues in sewage sludge
- Eliminates biosolids production, hauling, and disposal
- Protects public health and aquatic ecosystems
- Scalable, onsite, compact, and compliant with strict air standards
- New income stream from surplus power and ash-based green building materials
The Regulatory Landscape
The EPA is conducting a multi-year PFAS risk assessment to establish PFAS limits, a process expected to take another five years to complete, and one that is shaped by both science and politics. Meanwhile, states are beginning to move ahead with restrictive limits:
- Legislation to regulate: Arizona, California, Hawaii, Illinois, Indiana, Maryland, Massachusetts, Mississippi, New York, Oklahoma, Oregon, Texas, Washington
- Regulations in place: California, Connecticut, Maryland, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New York, Pennsylvania, Vermont, Wisconsin, and Canada.
Call to Action
Concerns over PFAS in sewage sludge are intensifying the need for commercially viable sludge treatment solutions that can effectively destroy PFAS. The wastewater industry faces a crucial choice. It must be either:
- Continue outdated practices that spread PFAS, and lobby for favorable regulations, or
- Transition to advanced, sustainable solutions that can eliminate PFAS.
Gate 5 Infrastructure offers a clear path forward to eliminating PFAS in sludge through thermal treatment, while generating clean energy, water, and building materials. To learn more, contact us at www.gate-5.com or moc.5-etag@ofni.
