Advanced Oxidation Process Patent Landscape 2026
Advanced Oxidation Process Patent Landscape in 2026
The advanced oxidation process (AOP) patent field is moderately concentrated, with Evoqua Water Technologies holding a commanding lead over a long tail of challengers; water and wastewater treatment dominates the technology mix. Activity peaked in 2020 and has since eased on an annual basis, signaling a maturing field where strategic positioning in adjacent branches — such as electrolytic production and sterilization — may offer the clearest differentiation.
Evoqua leads a moderately concentrated field with a long challenger tail
Evoqua Water Technologies LLC holds the top position by a substantial margin, followed by NCH Corp, Trevi Systems, and Air Liquide — a ranking that reflects the field’s commercial orientation toward industrial and municipal water treatment.
The top five filers account for 27% of the combined total among the hundred largest filers, indicating moderate concentration: a single clear leader exists, but no oligopoly has formed. A large number of smaller applicants — including academic institutions such as Tianjin University and Nanjing University — sustain a competitive second tier.
| # | Applicant | Patent families | Share |
|---|---|---|---|
| 1 | Evoqua Water Technologies LLC | 197 | |
| 2 | NCH Corp | 64 | |
| 3 | Trevi Systems Inc | 40 | |
| 4 | LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PR… | 29 | |
| 5 | Greenthread Ltd | 28 | |
| 6 | AIR PROD & CHEM INC | 27 | |
| 7 | Toshiba Corporation | 26 | |
| 8 | Access Business Group International LLC | 25 | |
| 9 | Blucher GmbH | 24 | |
| 10 | Applied Process Tech | 23 |
| # | Applicant | Patent families | Share |
|---|---|---|---|
| 11 | UV Cleaning Systems Inc | 23 | |
| 12 | KOREA INST OF CIVIL ENG & BUILDING TECH | 23 | |
| 13 | Permascand | 22 | |
| 14 | Tianjin University | 19 | |
| 15 | Yokogawa Electric Corporation | 18 | |
| 16 | Clean Chem Inc | 18 | |
| 17 | Nanjing University | 17 | |
| 18 | De Nora Permelec Ltd | 16 | |
| 19 | VEOLIA WATER SOLUTIONS & TECHNOLOGIES SUPPORT SAS | 16 | |
| 20 | De Nora Marine Technologies LLC | 15 |
Evoqua’s scale implies significant freedom-to-operate risks for new entrants in core water treatment routes; however, the breadth of the applicant base across universities and specialist firms signals that process innovation and niche application areas remain actively contested.
Filing data for approximately the most recent 18–24 months is subject to publication lag and likely understates actual activity; trend readings for 2025–2026 should be treated as provisional. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
Activity peaked in 2020 and water treatment anchors the technology mix
The annual filing trend chart and IPC composition chart together reveal where momentum has been built and where it remains thin — useful inputs for prioritizing R&D bets.
Annual filing trend
Filings ramped from 147 in 2017 to a peak of 244 in 2020, then declined steadily through 2023, with a partial rebound to 182 in 2024. The 2025 and 2026 figures (127 and 14 respectively) reflect publication lag and should not be read as a continued decline. The overall multi-year trajectory confirms a field that expanded strongly through 2020 and has since moderated.
↗ Hover for values · click a bar to ask EurekaTechnology composition
C02F (water and wastewater treatment) dominates the technology mix by a wide margin, with B01D (separation/filtration) and B01J (chemical and physical processes and catalysis) forming a secondary cluster. Lower-share branches — including C25B (electrolytic production), A61L (sterilization and disinfection), and B01F (mixing and stirring) — sit at the margins and represent areas where filing density is comparatively sparse relative to the core.
↗ Hover for values · click a bar to ask EurekaHighly cited patent families surfaced by the query
Citation-heavy patent families returned by the query. Use this section as citation context, not as a curated list of the most topic-specific patents.
Systems and methods for producing ultrapure water …
Systems and methods for producing ultrapure water (UPW) for use in semiconductor fabrication include an ABA module that performs an advanced oxidation process (AOP) pre-treatment step, a bioremediation step, and an advanced oxidation process post-treatment step. Raw water flows through the ABA module, which is part of a water treatment system for producing… (excerpt from the patent abstract)
| # | Patent | Citations |
|---|---|---|
| 1 | Aqueous treatment apparatus utilizing precursor ma… | 234 |
| 2 | Method and apparatus for closed loop recycling of … | 126 |
| 3 | Doped carbonaceous materials for photocatalytic re… | 117 |
| 4 | Use of controlled periodic illumination for an imp… | 108 |
| 5 | Electrochemical carbon nanotube filter and method | 107 |
| 6 | Method and apparatus for UV-oxidation of toxics in… | 100 |
| 7 | Doped graphitic carbon nitrides, methods of making… | 95 |
| 8 | Process and apparatus for oxidation of contaminant… | 88 |
Ranked by total forward citations. Citation counts favour older and broadly cited patent families, and broad or adjacent patents may appear when they match the search scope. Treat this section as citation context, not as a curated list of the most topic-specific patents. Some patent titles may be shown in their original, non-English language where an accurate translation could not be guaranteed.
What the patent structure means for R&D and investment decisions
Four structural dimensions — maturity, concentration, collaboration, and geography — each carry direct implications for where new investment is likely to generate defensible IP.
Past-peak: field is maturing after a 2020 surge
The lifecycle stage is Decline, with annual filings easing back from the 2020 peak of 244 families. On a multi-year basis the corpus remains substantial at 1,543 patent families, but the annual deceleration signals that the foundational solution space is crowded. R&D investment is best directed toward differentiated variants — novel oxidant combinations, hybrid membrane-AOP systems — rather than incremental repetition of established routes.
Past-peak · 2020 peakModerate concentration with an accessible second tier
The top five filers account for 27% of the hundred largest filers’ combined total, with Evoqua holding nearly 197 patent families — more than three times the next-ranked applicant, NCH Corp at 64. Below the top five, the ranking disperses quickly across specialist firms and universities. This structure means the core water treatment space carries meaningful freedom-to-operate risk from Evoqua’s portfolio, while adjacent application areas remain more open.
Moderate concentrationCorporate-affiliate co-filing dominates observed collaboration
The most active co-filing pairs are Toshiba Corporation with Toshiba Infrastructure Systems and Solutions Corporation (14 joint filings) and Air Liquide’s parent entity with Air Liquide America (13 joint filings). Both pairs reflect intra-group coordination rather than external partnerships, suggesting that cross-company R&D collaboration in AOP remains limited. New entrants seeking ecosystem leverage may find the collaborative landscape relatively open to genuine external partnerships.
Intra-group co-filingUS and China lead; Asia-Pacific and Europe add meaningful coverage
The United States leads jurisdiction coverage, followed closely by China, with WIPO PCT and EPO applications indicating active international prosecution strategies. South Korea and India each carry substantial records, reflecting regional treatment infrastructure investment. Germany and Israel also appear in the top ten jurisdictions, pointing to European industrial and municipal water market relevance. New filings should consider PCT and EPO routes for broadest protection given the geographic spread of end markets.
US · China · PCT · EPOGo beyond the landscape: Eureka’s TRIZ Solution agent breaks down an R&D problem and returns patented concept solutions, each with a technical approach and cited patent & literature evidence.
| Applicant | Collaborator | Co-filings |
|---|---|---|
| Toshiba Corporation | Toshiba Infrastructure Systems & Solutions Corporation | 14 |
| L’Air Liquide SA pour l’Etude et l’Exploitation des Procedes Georges Claude | Air Liquide America Inc | 13 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
Evoqua dominates water treatment routes; Air Liquide pivots on mixing and gas delivery
The top two players differ in both scale and technology emphasis: Evoqua concentrates on water treatment and separation, while Air Liquide’s AOP portfolio emphasizes mixing and gas-delivery processes.
Evoqua Water Technologies LLC
Evoqua holds 197 patent families — the largest position in the field by a wide margin — concentrated in C02F water and wastewater treatment (176 records) and B01D separation processes (42 records). Its recent filing trend shows a decline of 39% versus the prior three-year period, suggesting the portfolio is maturing rather than expanding. Despite the deceleration, Evoqua’s depth in core treatment routes makes it the primary freedom-to-operate reference for any new entrant.
families: 197L’Air Liquide SA
Air Liquide’s AOP portfolio of 29 patent families is concentrated in C02F water treatment (31 records) but distinguished by a significant presence in B01F mixing and stirring (18 records under B01F 23 and 8 under B01F 3), reflecting a gas-injection and ozone-dissolution emphasis that differs from Evoqua’s filtration-heavy approach. The recent filing trend shows a sharp decline of 95% versus the prior period — consistent with a small recent-window base — and intra-group collaboration with Air Liquide America (13 joint filings) amplifies its effective portfolio reach.
families: 29| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| Evoqua Water Technologies LLC | 47 | ▼ -39% |
| L’Air Liquide SA pour l’Etude et l’Exploitation des Procedes Georges Claude | 1 | ▼ -95% |
| Access Business Group International LLC | 5 | ▼ -64% |
Under-served routes adjacent to the AOP core worth monitoring
Several IPC branches sit at the periphery of the AOP corpus with low filing density relative to the dominant C02F class; two in particular have plausible technical synergies and realistic entry paths.
C25B · Electrolytic production of compounds
With 134 patent records and a 3% share of the corpus, electrolytic AOP routes — including electrochemical ozone and hydroxyl-radical generation — are notably sparse given the growing interest in on-site oxidant production for decentralized water treatment. Incumbent depth in this branch is low relative to the core, and the technology overlaps naturally with AOP hardware already deployed in municipal and industrial settings. A focused filing program in electrochemical reactor design and electrode materials could establish a defensible position ahead of wider adoption.
Search this in Eureka →A61L · Sterilising & disinfecting
AOP applications in sterilization and medical-grade disinfection account for only 106 patent records and a 2% share, despite the mechanistic overlap between hydroxyl-radical chemistry used in water treatment and high-efficacy pathogen inactivation. This branch has plausible value in hospital wastewater treatment, surface decontamination, and food-contact surface sanitation — sectors with tightening regulatory requirements. The sparse filing density and absence of a dominant incumbent in this intersection suggest it is an observable gap, though commercial path clarity would need further market validation.
Search this in Eureka →How leading applicants differ across AOP technology routes
Strength of each leader across the main technology routes.
| Player | C02F 1 · Water & wastewater treatment | C02F 101 · Water & wastewater treatment | C02F 9 · Water & wastewater treatment | C02F 103 · Water & wastewater treatment | C02F 3 · Water & wastewater treatment |
|---|---|---|---|---|---|
| Evoqua Water Technologies LLC | Strong · 176 | Emerging · 24 | Emerging · 32 | Moderate · 71 | Absent |
| NCH Corp | Strong · 64 | Absent | Absent | Moderate · 16 | Absent |
| Blucher GmbH | Strong · 24 | Moderate · 11 | Absent | Absent | Absent |
| Trevi Systems Inc | Strong · 34 | Absent | Absent | Absent | Absent |
| Access Business Group International LLC | Strong · 25 | Absent | Moderate · 7 | Absent | Absent |
| L’Air Liquide SA pour l’Etude et l’Exploitation des Procedes Georges Claude | Strong · 31 | Absent | Absent | Absent | Absent |
| Greensource Fabrication LLC | Absent | Strong · 9 | Strong · 13 | Strong · 9 | Absent |
Frequently asked questions
The corpus analyzed contains 1,543 patent families in scope, covering global filings across multiple jurisdictions and IPC classes relevant to AOP technology.
Evoqua Water Technologies LLC holds the largest portfolio at 197 patent families, which is more than three times the second-ranked filer, NCH Corp at 64 patent families.
The field is assessed as past its peak. Annual filings reached a high of 244 in 2020 and have since eased, though the multi-year corpus remains substantial. The 2025–2026 data reflects publication lag and does not confirm a continued decline.
The United States leads with 583 patent records, followed by China with 517, WIPO PCT with 277, and the EPO with 269. South Korea and India also carry significant coverage, reflecting active water infrastructure investment in those markets.
C02F (water and wastewater treatment) is the dominant IPC class by a wide margin. B01D (separation and filtration) and B01J (chemical and physical processes and catalysis) form a secondary cluster. Adjacent branches such as C25B (electrolytic production) and A61L (sterilization) have comparatively low filing density.
The most active co-filing pairs identified are Toshiba Corporation with Toshiba Infrastructure Systems and Solutions Corporation (14 joint filings), and Air Liquide’s parent entity with Air Liquide America (13 joint filings). Both pairs reflect intra-group coordination rather than cross-company partnerships.
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Disclaimer. This page is generated from PatSnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
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