Q&A: PFAS Due Diligence – Biosolids
What are biosolids, and how are they managed?
Biosolids are sewage sludge, or the primarily organic semi-solid byproduct of wastewater treatment plants (WWTP). They are commonly reused for land application because of their nutrients and ability to function as soil conditioners and fertilizers. According to EPA’s annual biosolids reports (CY2022), about 55% of biosolids produced in the U.S. are land-applied, primarily for agricultural enrichment, with other uses including home gardens, landscaping, and golf courses. Alternate fates for biosolids include disposal via landfilling and incineration.1
Do all biosolids contain PFAS?
While wastewater discharges from certain industrial operations2 typically contribute higher PFAS loads to WWTP, studies show that even biosolids from domestic sewage streams consistently contain certain PFAS. This is because PFAS have been used for decades in a vast array of consumer products, including many common household items like pharmaceuticals, non-stick cookware, cleaning products, cosmetics, food packaging, and water-resistant clothing. PFAS can also enter household waste streams via gray water from washing machine discharges and urine excretion. PFAS tend to accumulate in sewage sludge because most WWTP are unequipped to properly remove or destroy the chemicals.
Where can information be found regarding the application of biosolids?
Regulatory records of the application of biosolids may be available at the local, state, and/or federal level. In 1984, EPA issued a policy promoting the beneficial uses of biosolids and, in 1993, began regulating the use or disposal of sewage sludge biosolids (Part 503 rule). The Part 503 rule is largely self-implementing, with reporting only required for certain publicly owned treatment works. Furthermore, farmers or landowners receiving biosolids (e.g., land appliers) are exempt from permit applications, although they are required to keep certain records for five years. States can apply to EPA for the approval of a biosolids program, which must be at least as stringent as federal requirements.
Understanding the resources available to gather information regarding a biosolids application at a site is a key first step. Langan’s team of PFAS experts can source relevant information on behalf of clients, including:
- Permit applications submitted to federal, state, and local agencies.
- Searches of available state-maintained environmental databases and/or GIS maps.
- Interviews with knowledgeable current and past owners or operators.
- Requests for documents like bills of lading or inquiries to the local WWTP.
- Reviews of prior reports that reference biosolids applications.
Once gathered, the team applies its practical experience to identify and resolve potential environmental risks and liabilities associated with biosolids.
Is a biosolids application considered an ASTM Phase I ESA Recognized Environmental Condition (REC)?
Like most PFAS topics, the question of whether a biosolids application constitutes an REC is hotly debated and ultimately consigned to professional judgment. EPA’s Part 503 Biosolids Rule does not include standards for PFAS. Additionally, EPA has not provided guidance on handling the classification of biosolids as part of due diligence completed for purchaser and land-owner defenses and liability protection under federal CERCLA law. Some could argue that the use of biosolids is considered a normal application of fertilizer, which can be interpreted as exempt from being qualified as a CERCLA-defined “release,” and, therefore, not an REC. Others could argue that PFOA and PFOS are CERCLA hazardous substances, and land application of biosolids containing PFOA and PFOS does not qualify as a “normal application of fertilizer,” therefore, considering it a release and constituting an REC.
Without clear or consistent guidance available, it is important to engage an environmental professional to consider and evaluate all potential ramifications of biosolids applications on potential environmental liability when conducting due diligence for property transactions.
Cortney Savidge is a Senior Project Manager with over 14 years of experience focused on environmental contamination investigation and remediation projects. She specializes in planning, implementing, and closing out cleanup projects, due diligence consulting, fill management, and brownfield redevelopment.
1 https://www.epa.gov/system/files/documents/2025-01/draft-ra-public-webinar-slides.pdf
2 Such as organic chemicals, plastics, and synthetic fibers manufacturing; metal finishing; pulp, paper, and paperboard manufacturing; textile mills; and commercial airports: https://www.epa.gov/system/files/documents/2021-09/multi-industry-pfas-study_preliminary-2021-report_508_2021.09.08.pdf