Per- and polyfluoroalkyl substances (PFAS), also referred to as “forever chemicals”, pose serious health and environmental risks due to their long-lasting nature, harmful effects, and widespread application across diverse industrial and commercial sectors. Exposure to PFAS has been linked with several forms of cancer and immune suppression, as well as thyroid gland dysfunction and developmental delays (EPA, 2023). These risks have prompted heightened scrutiny from regulators and have become a source of concern for stakeholders, including communities, developers, and businesses
Risks – PFAS Site Assessment
For stakeholders involved in real estate acquisitions, manufacturing, or land development, the potential presence of PFAS contamination represents a significant environmental business risk, particularly during site assessments. One of the key risks lies in regulatory liability. As environmental regulations tighten globally, businesses may be held responsible for investigating and remediating PFAS contamination even if the pollution predates their ownership. Failure to conduct thorough PFAS assessments during property transactions can lead to unforeseen cleanup costs, legal disputes, and reputational damage. Financial implications are also substantial. PFAS site assessments are complex and costly, requiring advanced sampling methods and laboratory analysis.
If contamination is found, long-term remediation efforts can span decades and impact property values, project timelines, and investment returns. Insurance coverage for PFAS-related issues is often limited, increasing the financial burden on businesses. Engaging a qualified environmental consultant before property acquisition activities is essential to managing these risks effectively. Early involvement is critical to conducting PFAS due diligence, including preliminary site assessments, data gap evaluations, and sampling programs, to characterize potential liabilities and provide the technical basis for informed investment decisions.
Also consider operational risks. Discovering PFAS contamination can delay permitting processes or halt development altogether. For manufacturers, it may lead to stricter discharge permits or operational constraints, affecting productivity and profitability. Industries such as chemical manufacturing, textiles, automotive, aerospace, firefighting, and wastewater treatment have been linked to PFAS use and discharge over the last years (ATSDR, 2022). In these sectors, proactive assessments help avoid regulatory surprises and support risk mitigation strategies.
Groundwater – PFAS Site Assessment
Some states have developed groundwater standards that differ from federal drinking water limits. Technically, when PFAS levels exceed drinking water thresholds but remain under state groundwater standards, delaying immediate cleanup is possible and safe. However, such findings signal potential liability, particularly as regulations evolve or litigation arises (ITRC, 2021).
Businesses are encouraged to incorporate PFAS evaluations into their environmental due diligence protocols to address PFAS-related risks proactively. Diligence includes engaging experienced environmental consultants, staying informed about evolving regulations, and transparently communicating findings with stakeholders. As legal and regulatory requirements tighten, proactive site assessment has become critical to responsible environmental management and risk reduction. These practices support compliance and contribute to long-term sustainability and organizational resilience.
PFAS Site Assessment Sources:
Meet the Authors:
Leslie P. Smith, Ph.D., PE has over 10 years of experience, and is responsible for project management and design in the environmental engineering and remediation field, which of environmental site assessments, soil and groundwater remediation design and implementation, drainage assessment plans, soil management plans, construction dewatering permitting, technical writing, includes client relations, contract management, project strategy development, regulatory interaction, e client relations, contract management, project strategy development, regulatory interaction and quality assurance. Reach out to Leslie on LinkedIn.
Natalia Marquez is responsible for project support in liquids management and environmental services. She works on diverse projects both performing field activities and soil and liquids management, remediation, environmental assessments, data management, and technical writing. Natalia has also acted as Assistant Project Manager on complex projects managing field activities, scheduling, and reporting. Reach out to Natalia on LinkedIn.
On September 17, 2025, the U.S. Environmental Protection Agency (EPA) announced the next steps regarding regulatory efforts to address the cleanup of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). In the press release, EPA Administrator Zeldin said, “…we will need new statutory language from Congress to fully address our concerns with passive receiver liability.”
CERCLA imposes broad, retroactive, and potentially costly strict liability on those who release hazardous substances to the environment. This liability can sometimes attach to entities that did not manufacture or generate the substance but received it in feedstocks, products, or landfilled waste. The EPA refers to these entities as “passive receivers.” Members of Congress received testimony and input from various industries, including private and municipal landfills, and passed it to the EPA, which intends to continue working with Congress. No workshops or additional input forums were announced.
The major concern for passive PFOA and PFOS contamination receivers, including local municipalities and service providers, is potentially passing decontamination costs onto ratepayers, taxpayers, and consumers. EPA will continue to collect information on its costs and benefits, but feels the best solution to this issue is a statutory fix to protect passive receivers from liability.
For now, EPA is retaining the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) hazardous substance designation for PFOA and PFOS and will initiate future rulemaking to establish a uniform framework governing the designation of hazardous substances under section 102(a) of CERCLA moving forward. The current rule mandates reporting of releases of one pound or more of PFOA or PFOS within 24 hours. It designates Perfluorooctanoic Acid (PFOA) and Perfluorooctane sulfonic Acid (PFOS) as CERCLA hazardous substances. See 42 U.S.C §9602; Docket EPA-HQ-OLEM-2019-0341.
According to the EPA, a CERCLA section 102(a) Framework Rule would provide a uniform approach to guide future hazardous substance designations, including how the agency will consider the costs of proposed designations. Section 102(a) gives the EPA authority to designate additional hazardous substances beyond those listed under the other statutes referenced in CERCLA (the Clean Water Act, the Clean Air Act, the Resource Conservation and Recovery Act, and the Toxic Substances Control Act). Once finalized, the 102(a) Framework Rule would provide a uniform approach for future designations.
In response to the EPA’s August 26, 2022, proposed rule to list PFOA and PFOS as CERCLA hazardous substances, numerous comments were submitted requesting that the final CERCLA HS rule include exemptions or similar liability relief for passive receivers that did not generate the chemicals – e.g., landfills, wastewater treatment facilities, and water supply systems.
Background
EPA’s May 8, 2024, final CERCLA HS rule did not provide an exemption. However, EPA’s April 19, 2024, Memorandum entitled “PFAS Enforcement Discretion and Settlement Policy Under CERCLA” outlines enforcement discretion considerations for the following entities:
(1) Community water systems and publicly owned treatment works (POTWs)
(2) Municipal separate storm sewer systems (MS4s);
(3) Publicly owned/operated municipal solid waste landfills;
(4) Publicly owned airports and local fire departments; and
(5) Farms where biosolids are applied to the land.
Despite the enforcement discretion policy, some passive receivers were disappointed that the agency did not provide stronger liability protection. Based on EPA’s September 2025 press release (above), EPA now plans to take a closer look at the issue, including the possibility of providing a statutory fix to protect passive receivers from liability.
If you have questions regarding this rule, please get in touch with SCS Engineers.
SCS Engineers is proud to take part in Engineering Career Night at Messiah University.
This event provides students the opportunity to network with industry professionals, attend targeted workshops, and explore career paths across engineering disciplines. Join us in Brubaker Auditorium at the Eisenhower Campus Complex to connect with our team and learn more about internships, co-ops, and full-time roles with SCS Engineers.
At SCS, we combine engineering expertise with a passion for sustainability—delivering innovative solutions in solid waste management, renewable energy, remediation, and infrastructure. We look forward to meeting students who are ready to plan their careers and make an impact in their communities.
SCS Engineers is excited to attend Day 2 of the upcoming career fair focused on Architecture, Construction, and Structural Design and Engineering roles!
With more than 50 years of experience, SCS provides innovative environmental engineering and consulting services in solid waste management, renewable energy, remediation, and sustainable infrastructure. We’re looking forward to connecting with students and alumni across 11 colleges and 190+ degree programs who are eager to explore careers that combine engineering expertise with real-world impact.
Join us on Day 2 to learn more about internships, Co-Op placements, and full-time opportunities at SCS Engineers. Whether you’re just beginning your journey or preparing for your next step, you’ll find exciting ways to grow your career while making a positive difference for communities and the environment.
Join SCS Engineers at the University of Wisconsin-Platteville 2025 Fall Career & Internship/Co-op Fair September 24, 2025. Session 1: 9 a.m.–noon | Session 2: 3–6 p.m. Register now!
The Clean Water Act (CWA) specifies various technology-based Effluent Limitations Guidelines (ELGs) for direct and indirect dischargers. These ELGs include:
EPA evaluated available technologies to treat or remove meat and poultry (MPP) pollutants individually and in treatment trains, as shown below in subsections, based on the type of pollutant removal, including conventional pollutants, phosphorus, nitrogen, pathogens, and chlorides.
Conventional Pollutant Removal
MPP process wastewater contains oil & grease, TSS, and BOD, all conventional pollutants removed with primary treatment, which removes floating and settle-able solids. Typical treatment technologies include screening and DAF.
Facilities may add polymers, flocculants, and phosphorus-precipitating chemicals to or before the DAF. The chemical addition increases the removal of pollutants from the wastewater. Adding chemicals to remove phosphorus can help facilities meet phosphorus effluent limits. Chemical addition may not be possible for facilities that recycle materials from the DAF to the facility, as this would contaminate the raw material.
Biological/Organic Pollutant Removal an Attractive Option
Biological, physical, and chemical processes remove BOD, nitrogen, and phosphorus. Biological processes are useful to achieve low levels of BOD and nitrogen and are common at MPP facilities. Microorganisms in biological wastewater treatment require phosphorus for cell synthesis and energy transport, typically removing 10 to 30 percent of influent phosphorus. Through biological treatment, organic compounds break down with bacteria into water, CO2, N2, and CH4 products.
Biological treatment systems are often used in series to achieve high nitrogen removal rates. Wastewater flows from one system to the next, with recycle streams and returned activated sludge returning to various system locations. Some examples include:
iii. Modified Bardenpho: This is a five-stage process: anaerobic, anoxic, aerobic, anoxic, aerobic, followed by a secondary clarifier. As in the Bardenpho process, mixed liquor with high nitrate levels is recycled from the first aerobic stage to the first anoxic stage, and activated sludge from the clarifier is recycled back to the influent. The anaerobic stage at the beginning of the system results in biological phosphorus removal. Phosphate-accumulating organisms (PAOs) are recycled from the aerobic stage in the mixed liquor to the anaerobic stage. In the following aerobic stages, PAOs uptake large amounts of phosphorus.
Phosphorus Removal
As mentioned in the biological/organic pollutant removal section, some phosphorus is removed in biological treatment processes. Chemical addition and/or tertiary filters achieve low phosphorus levels.
Pathogen Removal
Disinfection destroys remaining pathogenic microorganisms and is generally required for all MPP wastewater discharged to surface waters. Chlorination/dechlorination, Ultra-Violet (UV), and some filters can meet effluent limits for pathogens and inactivate pathogenic microorganisms before discharge to surface waters.
Chloride Removal
Some MPP processes, including hides processing, meat and poultry koshering, and further processing techniques, such as curing, brining, and pickling, commonly produce wastewater streams with high levels of chlorides. Some facilities use water softening, which can also produce high chloride wastestreams. Wastewater treatment technologies commonly found at POTWs and many MPP facilities do not remove chlorides. The optimal chloride treatment technologies for a facility depend on wastewater strength, climate, land availability, and cost. High chloride wastestreams may be able to be separated from other wastestreams, which can reduce costs and energy required for treatment.
Solids Handling
Some wastewater treatment technologies produce industrial sludge. In the MPP industry, DAF and clarifiers primarily generate sludge. The sludge contains oil & grease, organic materials, nitrogen, phosphorus, and chemicals/polymers added in the treatment system. The sludge may have a high water content, which can be reduced to reduce volume and save on hauling and landfilling costs. Common dewatering technologies include gravity thickening units and the belt filter press. The sludge may be incinerated, land applied, or landfilled, depending on state, local, and federal regulations and disposal method availability.
Additional Information About PFAS Removal – Foam fractionation is a separation process that leverages the affinity of certain molecules for the air-liquid interface to isolate and concentrate them. It works by bubbling gas through a liquid, causing the target molecules to adsorb onto the surface of the bubbles and rise to the top, forming a foam that is removed. This process is useful for removing and concentrating per- and polyfluoroalkyl substances (PFAS) from water and wastewater.
An energy company using coal (many still do as they transition to renewable energy sources) uses desulfurization for its flue gas, preventing air pollution and creating gypsum as a by-product. Fly ash, another by-product of creating energy, is sold to concrete companies for a profit. The wastewater used in these green processes has high chloride. It is pretreated to ensure the chemistry of the wastewater is safe before injecting it into an EPA and state regulatory agencies-approved Class I well below drinking water aquifers.
Pretreatment helps to ensure the energy company does not decrease the capacity of the well to accept wastewater. Chemical characterization of the wastewater in the permitting process and regular sampling during operations helps ensure the fluid is non-hazardous and unchanged.
Using green practices, this energy company prevents air and water pollution, protects drinking water resources, and qualifies as a zero-discharge facility. The bottom line is that they provide energy at a reasonable cost; the company is profitable from its green practices and protects health and human life.
That’s sustainability that empowers the safety of electric utilities as they provide for our energy needs.
You are welcome to make use of SCS Engineers’ extensive library of papers, blogs, and videos for the power sector. Here are a few suggestions:
Professional Geologist Jake Dyson is responsible for permitting, drilling, regulatory compliance, and operating Class I, II, V, and VI UIC wells. Dyson manages permitting, testing, and workovers of UIC wells and serves his clients as a technical advisor on developing and executing well construction material, formation fluid, and well testing programs, including managing drilling and construction costs, interpreting geologic data for model inputs, and developing static geologic models. You can reach Jake at SCS Engineers or on LinkedIn.
The EPA proposes updated effluent limitation guidelines (ELGs) for meat and poultry product facilities, aiming to reduce wastewater pollution, particularly nitrogen and phosphorus discharged from meat and poultry processing facilities. These changes affect meat and poultry industry facilities, including those that would apply to additional direct and indirect dischargers.
There is growing concern as local and state ELGs are also beginning to appear. These new guidelines can impact the meat and poultry industry and the food and beverage industry. In summary, the federal guidelines are influencing state and local plans.
Meat:
Poultry Processing:
Overall, the proposed changes in effluent limitation guidelines by the EPA represent a significant shift in regulatory expectations for the meat and poultry industry. SCS Engineers provides webinars and resources that provide crucial insights and guidance for industry stakeholders to navigate these changes effectively.
SCS Engineers provides these free resources:
Hydrogen sulfide (H2S) is often identified as a potential culprit of odors and nuisance complaints near municipal solid waste (MSW) landfills. Some base their complaints on information found on the Internet as fact. As experts, let’s start by saying data from other landfills or pulled from an AI browser summary online will not provide accurate answers. H2S concentrations vary widely and are unique to individual landfills.
How is H2S generated in an MSW landfill, and why do concentrations vary?
Calcium sulfate (CaSO4•2H2O, aka gypsum), the primary ingredient in wallboard (aka drywall), can be biologically converted to H2S under select and somewhat rare conditions. Specifically, seven conditions are required for the biodegradation of gypsum to H2S. See (Gypsum Association, Industry Technical Paper: Treatment and Disposal of Gypsum Board Waste (Jan. 1991); Gypsum Association, Treatment and Disposal of Gypsum Board Waste, Part II, Technical Paper (Mar. 1992).
Condition 1 – Liquid Water. The biological conversion of sulfate to H2S occurs in the aqueous phase—i.e., sufficient free liquids must be present, and sulfates must dissolve into the free liquids. Modern landfills with leachate collection systems may experience intermittent perched and discrete zones of saturation within the waste mass, particularly following periods of extended precipitation. Low-permeability confining layers (e.g., clay or clay-like soil used for intermediate cover) may temporarily trap water/leachate in discrete pockets within the landfill.
Condition 2 – Source of Soluble Sulfate. Gypsum, having the chemical formula CaSO4•2H2O, is a source of soluble sulfate. Gypsum sources include wallboard (aka drywall), flue gas desulfurization (FGD) material from coal-fired power plants, and some industrial wastes. Sulfates and sulfur compounds can also be present in lower concentrations in other waste streams, depending on what the MSW landfill accepts.
Condition 3 – Sulfate-reducing Bacteria. Sulfate-Reducing Bacteria (“SRB”) use dissolved sulfate as an electron acceptor in the oxidation of carbon. Primary SRB include Desulfovibrio and Desulfotomaculum. These SRBs, as well as many other bacteria, are commonly present in MSW landfills. However, the presence of SRB within a landfill may not be ubiquitous, and may be limited to regions where the other required conditions favor their existence and survival.
Condition 4 – Organic Material. SRBs use organic material as a food source to multiply and degrade sulfate to H2S. Carbon serves as a source of energy for the bacteria. Typical MSW has a high organic content due to a wide variety of organic materials such as wood, paper, cardboard, food, vegetative waste, and fabrics. Many communities with recycling programs help divert these waste materials for reuse and recycling.
Condition 5 – Anoxic Environment. SRBs thrive under anoxic (without oxygen) conditions. The presence of oxygen can kill SRBs. While anoxic conditions are typically not present in areas where MSW was recently disposed, they are typical in portions of MSW landfills where organic wastes have been present for at least a few months and decompose to produce methane and carbon dioxide.
Condition 6 – Appropriate pH Range. SRB reduction of sulfate to H2S is reportedly optimum within a pH range of about 7 to 8, and does not occur outside a pH range of about 4 to 9. The pH range within a typical MSW landfill falls within this activity range.
Condition 7 – Appropriate Temperature Range. SRB reproduction and H2S generation are reportedly optimum within a range of about 30 °C to 38 °C (86 °F to 100 °F). Many MSW landfills are within or a little above this optimum range. Studies of SRB in geologic environmental settings found reduced activity above about 60 °C (140 °F), and no activity above about 80 °C (176 °F). Similarly, SRB activity ceases in freezing conditions.
In summary, although the necessary conditions for H2S generation are likely intermittently present within some discrete pockets within many MSW landfills, the conditions are not likely ubiquitous throughout the waste. MSW landfill conditions and waste composition are typically highly heterogeneous with respect to both location within the landfill and time. Thus, there are zones within landfills where many, but not all of the seven required conditions are present, and H2S generation does not occur. For example, there are undoubtedly many regions within landfills where free liquids (i.e., saturated conditions) are not present and, therefore, SRB conversion of sulfates to H2S does not occur, despite the presence of the other six conditions.
Similarly, a landfill may have pockets where bulk sulfate-containing waste has been disposed of but where the internal portion of the pocket is not exposed to moisture, organics, or SRB—each a necessary condition for converting sulfate to H2S.
Considering these seven conditions and heterogeneous landfill conditions, there are too many variables to provide a reliable and defendable quantitative model for H2S generation at all MSW landfills.
Monitoring and Treating Landfill H2S Conditions
We invite you to use our free resource library to learn more about how monitoring and data collection can protect your workers and the surrounding environment.
About the Author: Jeff Marshall, PE, is a Vice President of SCS Engineers and our National Expert on Emerging Contaminants (e.g., PFAS) and Innovative Technologies. He has over four decades of experience emphasizing environmental chemistry (e.g., hydrogen sulfide generation at MSW landfills), environmental permitting and compliance (e.g., fumigation facilities), hazardous materials/waste management, site assessment/remediation, treatment technologies, and human health risk issues. Hydrogen sulfide experience includes dozens of facilities, including landfills, coal-fired power plants, and paper mills.
In 2024, the EPA published a proposed regulation to revise existing Effluent Limitation Guidelines (ELGs) and pretreatment standards for the meat and poultry products (MPP) industry. The MPP industry includes meat and/or poultry slaughter facilities, further processing, or rendering. The industry also produces pet food and animal feed. In August 2025, the EPA decided not to move forward with additional ELGs or pretreatment standards for this industry. Published before this decision, you may find value in managing local or state regulations during this educational video.
Localities and states are also looking at the proposed federal guidelines to determine effluent limitations. Even though the federal proposed guidelines are aimed at the meat and poultry industry, some of the categorical waste streams could impact the food and beverage industry at the local or state levels. If meat or poultry is an ingredient, you’ll want to ensure your operation’s waste stream is correctly categorized.
Webinar Focus
SCS Engineers provided a webinar to help the industry understand the implications of ELG guidelines and its impact on local regulations. Dr. Todd DeJournett covers new regulations and stricter limits on nitrogen and the proposed phosphorus limits, pretreatment for oil and grease, total suspended solids, and biochemical oxygen demand. He also covers how your category can impact operations in the meat and poultry industry and the food and beverage industry.
Webinar Benefits
Attendees will better understand the compliance requirements, which will help determine your next steps to determine potential technical solutions, capital requirements (new equipment, & training), and the impact on operational costs from new waste streams. Early strategies are a significant asset, as states and localities are also beginning to impose stricter wastewater limitations, which could slow down the permitting process for your operation.
Who Should View and Your Privacy
The SCS webinars allow facility management, environmental, and sustainability staff to prepare for stricter guidelines.
This educational, non-commercial webinar with Q&A is free and open to all who want to learn more about EPA’s proposed effluent limitation guidelines.
Dr. Todd DeJournett is a Professional Engineer specializing in industrial water and wastewater treatment process design and effluent guideline regulatory policy. He has over 20 years of experience helping clients in the manufacturing industry make sound water and wastewater treatment and reuse plans and decisions. Dr. DeJournett developed new chemical modeling approaches and tools for adsorption, precipitation, pH adjustment, and other processes to assist with treatment process design, optimization, and troubleshooting of existing systems. He also adapted exploratory statistics/data mining methods using process and instrumentation data to aid in wastewater treatment process optimization/ troubleshooting.
Additional ELG Resources:
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