PFAS in semiconductor wastewater: Rising risks and the role of reverse osmosis
As regulatory standards tighten around PFAS discharge, the semiconductor industry faces escalating pressure to reduce these persistent pollutants in wastewater.
This article examines the challenges and treatment strategies associated with PFAS removal, especially ultrashort-chain compounds such as TFA, and evaluates the growing role of high-performance membranes, including nanofiltration and reverse osmosis, in addressing the unique demands of semiconductor fabrication facility (fab) effluent. The article also highlights the advantages of membrane-based treatment and underscores the importance of minimizing residual waste streams through approaches such as zero liquid discharge (ZLD) systems and PFAS destruction.
Introduction: A chemical dilemma at the heart of innovation
Semiconductors are the foundation of modern electronics, and their production relies heavily on complex chemical formulations, many of which include per- and polyfluoroalkyl substances (PFAS). These fluorinated compounds, prized for their stability and resistance to heat and chemicals, are integral to multiple stages of chip manufacturing. Yet, these very properties render PFAS environmentally persistent and biologically concerning.
The environmental footprint of semiconductor manufacturing is increasingly under the microscope as PFAS contamination is discovered in surface water, soil, air and drinking water around the world.
The specific PFAS profile in a facility’s wastewater is influenced by the types of products manufactured, process chemistries, equipment, wastewater segregation strategies and effluent treatment technologies. Regulatory and supply chain pressures have led to a shift from long-chain to short- and ultra-short-chain PFAS, which are more mobile and harder to remove with traditional treatment methods.
The most updated scientific, industry and academic data confirm that semiconductor wastewater streams contain a diverse and evolving PFAS profile, now routinely including ultra-short-chain molecules (C2–C3) alongside traditional short- and long-chain PFAS. Analytical limitations for these species have been largely overcome with new LC/MS and electrochemical methods, enabling accurate quantification and informing both regulatory compliance and technology development for PFAS abatement.
Of particular concern are ultrashort-chain PFAS such as trifluoroacetic acid (TFA), which are highly mobile and exceptionally difficult to remove. Since the semiconductor industry currently relies heavily on PFAS and no viable alternatives are expected in the near future, manufacturers face a critical challenge.
The regulatory landscape: From leniency to liability
As regulatory pressures and societal expectations continue to rise, the industry must adopt effective and scalable treatment solutions to prevent these persistent compounds from entering the environment and minimize waste streams.
While the U.S. is the first to set national enforceable limits for multiple PFAS in drinking water, several states and other countries had previously established standards for certain individual compounds. In 2024, the U.S. Environmental Protection Agency approved the National Primary Drinking Water Regulation (NPDWR), setting maximum contaminant levels (MCLs) for PFOS and PFOA and including additional PFAS under a cumulative hazard index, with full implementation expected by 2029.
Beyond drinking water regulation, the U.S. Environmental Protection Agency (EPA) is intensifying efforts to reduce PFAS discharges from industrial sources. In semiconductor manufacturing, PFAS concentrations in wastewater can vary widely. Consortium data from 26 global fabs show targeted PFAS discharges ranging from 0.002 grams/day to 13 grams/day, with an average of ~4 grams/day per facility (about 3.2 pounds/year). PFAS concentrations in wastewater can reach tens of thousands of ppt for certain compounds, with significant variability depending on fab size, product complexity, process chemistries and treatment methods.
As part of a broader strategy announced by administrator Lee Zeldin in April 2025, the EPA is developing effluent limitations guidelines (ELGs) that will set enforceable limits on PFAS concentrations in industrial wastewater, with the goal of stopping these persistent chemicals from entering drinking water systems and surrounding ecosystems.
In addition to discharge regulations, the EPA is taking steps to strengthen accountability and oversight across the PFAS lifecycle, such as PFAS reporting under the Toxic Release Inventory (TRI), and use the Resource Conservation and Recovery Act (RCRA) to address releases from PFAS manufacturers and users. Recognizing the importance of legal clarity, the EPA is also working with Congress and industry stakeholders to establish a clear liability framework rooted in the principle of "polluter pays," while safeguarding passive receivers.
In Europe, PFAS legislation is also progressing. In April 2025, the European Commission presented proposed revisions to the REACH Regulation, Europe’s key chemical safety law, aimed at simplifying compliance, modernizing oversight and reinforcing enforcement mechanisms. Under the proposed changes, registrations will require more frequent updates, new tests will be mandated even at lower production volumes, and member states will be subject to systematic and ad-hoc compliance audits.
Other countries such as Canada, Japan, Australia, Taiwan and China are imposing various restrictions on PFAS concentration in drinking water.
Understanding the PFAS profile in fab wastewater
Fabs use a wide array of PFAS-containing materials in photolithography, etching and wet cleaning. The Semiconductor PFAS Consortium has chosen to define PFAS as any organic chemical with a perfluorinated methylene group (-CF2-) and/or perfluorinated methyl group (-CF3) to ensure that efforts encompass all potentially regulated fluorocarbons.
The most commonly detected targeted PFAS in semiconductor fab wastewater include both sulfonic acids and carboxylic acids across a range of chain lengths. The dominant molecules are:
- Short-chain PFAS: Perfluorobutanesulfonic acid (PFBS, C4), perfluorohexanoic acid (PFHxA, C6), perfluorohexanesulfonic acid (PFHxS, C6).
- Longer-chain PFAS: Perfluorooctanoic acid (PFOA, C8), perfluorooctanesulfonic acid (PFOS, C8), perfluorononanoic acid (PFNA, C9) and others.
- Ultra-short-chain PFAS: New analytical techniques now allow for detection and quantification of ultra-short-chain PFAS (C2–C3, e.g., trifluoroacetic acid (TFA), perfluoropropionic acid (PFPrA)), which are increasingly present due to shifts in process chemistry and regulatory pressure on longer-chain compounds.
One of the most concerning among these is trifluoroacetic acid (TFA) which belongs to the subclass of per- and polyfluoroalkyl substances (PFAS) known as ultrashort-chain perfluoroalkyl acids (PFAAs). A recent study in Environmental Science & Technology characterized TFA as a global contaminant of emerging concern due to its persistence, mobility and increasing atmospheric formation via degradation of other fluorochemicals. While TFA currently lacks well-established health advisories or regulatory limits compared to other PFAAs, new guidelines are likely to emerge as research on its health and environmental impacts advances.
Membrane treatment solutions
Conventional water treatment processes, including coagulation, sedimentation and standard activated carbon filtration, are largely ineffective at removing PFAS, particularly the shorter-chain variants.
Reverse osmosis (RO) and tight nanofiltration (NF) membranes have emerged as leading contenders for PFAS removal in fabs wastewater streams due to their ability to reject a broad spectrum of compounds based on size and polarity. These pressure-driven membrane systems provide a physical barrier capable of achieving high rejection rates for both long- and short-chain PFAS.
Next stage: Concentration
Following membrane separation, which isolates PFAS into a concentrated brine stream, additional treatment is needed to further reduce PFAS volumes before final disposal or destruction.
While regenerable ion exchange and foam fractionation are effective in municipal or less complex industrial settings, they are not widely adopted in semiconductor fabs due to:
- Reduced efficiency for ultra-short-chain PFAS in high-salinity, high-complexity fab brines.
- Fouling and operational challenges in high-purity, high-throughput fab environments.
Targeting the whole spectrum of PFAS molecule length requires advanced concentration technologies that are pivotal for managing PFAS-laden streams. High-recovery solutions that enable up to 98% recovery rates can effectively concentrate brines to minimize volume and reduce the load on downstream processes. ZLD solutions complement these, which further process concentrated brines through thermal methods such as evaporation and crystallization, yielding solid residues and enabling near-complete water recovery. These integrated approaches not only enhance PFAS containment but also align with sustainability goals by promoting water reuse, minimizing environmental discharge and creating pre pre-concentration step for destruction
Managing the concentrate: A crucial next step
Nowadays, the common destruction practice is via high-temperature incineration (which raises environmental concerns and logistical challenges). Other emerging strategies under investigation include (but not limited to) those mentioned below:
- Electrochemical oxidation (EO): EO uses direct electron transfer and hydroxyl radical-mediated reactions to break down PFAS, converting them to fluoride ions, CO₂ and benign byproducts. Recent studies show that EO, especially with porous electrodes and flow-through reactors, is effective for the full PFAS spectrum and is being piloted for semiconductor brines.
○ SCWO: Operates at >374°C and 22.1 MPa, mineralizing PFAS with >99% efficiency in pilot trials.
○ HALT: Uses moderate heat and alkali to achieve full mineralization.
Both are being tested for high-strength, high-salinity brines typical of semiconductor concentrate streams
● Plasma treatment to degrade PFAS in the concentrate
These solutions are still in the developmental stage and currently require extremely high energy and chemical inputs. In the meantime, combining effective removal technologies such as RO/NF membranes with robust waste management practices like ZLD may offer the best pathway to full PFAS lifecycle management.
The path toward sustainable water management in semiconductors
As semiconductor manufacturers aim for net-zero water use and circular economy practices, PFAS adds a layer of complexity. Membrane systems can be designed to integrate into water reuse loops, where treated water is returned to non-critical operations or undergoes further polishing.
Key design considerations include:
- Source separation of high-PFAS process streams from lower-load utility flows
- Staged membrane treatment with real-time monitoring and optimization.
- Advanced brine handling and destruction technologies.
By adopting a system-level approach, fabs can mitigate PFAS discharge while enhancing water reuse and reducing overall water footprint.
Conclusion: A critical inflection point
The semiconductor industry stands at a crossroads. PFAS regulations are no longer hypothetical — they are here. And while chemical substitution and source reduction should remain long-term goals, advanced treatment technologies are urgently needed now.
Reverse osmosis and nanofiltration, designed for high recovery applications, offer reliable, scalable options to meet evolving regulatory and environmental expectations. As research advances and destructive technologies mature, these membrane systems will likely serve as the foundation of PFAS management strategies, not just in semiconductors, but across all industrial sectors grappling with this class of chemicals.
