Industrial Wastewater Treatment Patents: Leaders & Filing Trends 2026
- Filings peaked in 2019 and have declined since, with 2026 tracking well below the 2017 baseline — this is a maturing filing cycle, not a growing one.
- China accounts for roughly a third of all receiving-office activity, far ahead of the US, EPO, India, WIPO and Australia combined filings in any single office.
- Every tracked assignee shows zero filings in the latest year, a pattern consistent with the 18-month publication lag rather than an actual stop in R&D.
Filing growth compares 2021 (54 records) with 2024 (62) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 1,421 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Industrial wastewater treatment patenting spans biological treatment, advanced oxidation, sludge handling and heavy metal removal, filed against a core IPC footprint in C02F (water and wastewater treatment) and reaching into B01D separation processes, B01J catalysis and C12N microorganism engineering. The dataset covers 1,421 patent families published between 2015 and the 2026 cut-off, drawn from a search string anchored on COD removal, biological treatment, advanced oxidation, sludge handling and heavy metal removal claim language.
Filing activity is heavily weighted toward core water-treatment claims — C02F appears in nearly every record — with secondary clusters in filtration hardware and catalytic or biological process chemistry. That composition points to a field where the core unit operations are well claimed and differentiation increasingly happens in adjacent process integration and materials.
Filing trend and technology composition
Two views of the same 1,421-family dataset: filing volume over time by publication year, and the IPC subclasses that carry the underlying claims.
A filing cycle past its peak
Annual filings ran at 69 in 2017, rose to a peak of 79 in 2019, sat at 44 by the 2022 midpoint, and had fallen to 23 by 2026 (a partial year). Because publication lags filing by roughly 18 months, the most recent one or two years will always look thinner than they eventually turn out to be — but the multi-year decline from the 2019 peak predates that lag effect and reflects a real slowdown in new filing.
Core claims concentrated in one subclass
C02F covers 1,419 of 1,421 records — essentially the entire dataset — confirming this is a tightly defined water-treatment search. Secondary volume sits in B01D separation/filtration (154), B01J catalysis (75), C12N microorganism engineering (46) and B01F mixing (41), showing where treatment-process claims most often reach outside the core water-treatment classification.
Shares are the percentage of the 1,421 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Industrial Wastewater Treatment with Eureka
This page is one run against one query. Ask Eureka your own question about industrial wastewater treatment and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
US20190023593A1 — Wastewater treatment process and plant (SUEZ INTERNATIONAL, 2019)
Disclosed is a wastewater treatment process including at least one step of biological oxidation in a biological treatment unit, wherein ozone and an adsorbent compound are introduced, the ozonation and the adsorption each at least being induced upstream of the biological treatment unit, or else in the biological treatment unit, or else downstream of the biological treatment unit, knowing that downstream of the biological treatment unit at most either the introduction of ozone, or the introduction of the adsorbent compound is carried out. Also disclosed is a plant for implementing the process.Selected as representative of how leading filers combine advanced oxidation with biological treatment in a single claimed process rather than as separate unit operations.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5186821A | Wastewater treatment process with cooperating velocity equalization, aeration and decanting means | 116 |
| 2 | US20030038080A1 | Method and system for sustainable treatment of municipal and industrial waste water | 101 |
| 3 | US5316671A | Submersible aeration train and aeration apparatus for biological purification of sewage | 100 |
| 4 | US6288289B1 | Integrated effluent treatment process for nitroaromatic manufacture | 97 |
| 5 | US6758972B2 | Method and system for sustainable treatment of municipal and industrial waste water | 82 |
| 6 | EP1132347A2 | Integrated effluent treatment process for nitroaromatic manufacture | 82 |
| 7 | US4465597A | Treatment of industrial wastewaters | 82 |
| 8 | US20040007523A1 | Apparatus and method for wastewater treatment with enhanced solids reduction (ESR) | 77 |
| 9 | US4956093A | Wastewater treatment process | 66 |
| 10 | US5302285A | Propellant wastewater treatment process | 63 |
Citation counts favour older filings simply because they have had more time to be cited; read them as markers of influence on later drafting, not as a ranking of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-throughs from the filing trend, geography and citation data — useful for deciding where to file and where prior art risk is heaviest.
The cycle has turned down since 2019
Filings ran flat-to-declining from the 2019 peak through the 2022 midpoint and into 2026. Some of the most recent drop is publication lag, but the multi-year trend below peak is a genuine signal that core claim space here has been substantially staked out.
China is the dominant receiving office
China's 464 filings are more than double the next-largest office (US, 205), with EPO, India, WIPO and Australia trailing further behind. Freedom-to-operate work that skips a China search is working with an incomplete picture in this field.
Old aeration and equalization patents still anchor the art
The most-cited records date back to foundational aeration, decanting and municipal/industrial treatment integration patents, some over three decades old. New filings in biological treatment routes are still drafted against this base art.
Co-filing is rare and narrow
Only ten co-assignee pairs appear across the dataset, and the strongest — Bord na Móna and Wavin Ireland — accounts for just nine shared filings. Most patenting activity in this field is done by single assignees rather than joint ventures.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to industrial wastewater treatment, with the prior art for and against each one.
Who is filing, and where momentum has gone quiet
The assignee ranking is dominated by names with zero filings in the latest tracked year — read that alongside the 18-month publication lag before concluding anyone has stopped investing.
Latest-year filings read as zero, universally
Every assignee in the momentum table, including Evoqua Water Technologies LLC, Paradigm Environmental Technologies Inc. and Veolia Water Technologies Support, shows zero filings in the most recent year. That is consistent with publication lag rather than a sudden halt, but it means the true 2025-2026 leaderboard is not yet visible in the data.
Joint filing is the exception, not the rule
The strongest co-assignee relationship in the dataset, between Bord na Móna and Wavin Ireland, covers nine shared filings — well ahead of the next pairs at three each. Most assignees here build their portfolios independently.
Foundational aeration patents still shape drafting
The highest-cited record in the set is a 1990s aeration and decanting patent, still cited well above later filings on nitroaromatic effluent treatment and municipal-industrial integration. New biological-treatment claims are commonly drafted with this base art in view.
| Assignee | Recent year | YoY |
|---|---|---|
| Evoqua Water Technologies LLC | 0 | -100% |
| Paradigm Environmental Technologies Inc. | 0 | — |
| Premier Wastewater International, Inc. | 0 | — |
| Veolia Water Technologies Support | 0 | — |
| Cambi Technology AS | 0 | — |
| Royal HaskoningDHV Nederland B.V. | 0 | — |
| BORD NA MONA | 0 | — |
| Mitsubishi Materials Corporation | 0 | — |
Where to take this analysis
The filing trend and IPC composition point to a mature core with narrower openings at the edges. Two directions make sense from here.
Pressure-test a specific claim route
If a project sits inside ozone-biological hybrid sequencing, adsorbent polishing or catalytic COD reduction, run a targeted prior-art search against the most-cited records before drafting — the base art in this field is older than most teams expect.
Explore this in EurekaTrack the China filing gap
With China holding the largest single share of receiving-office activity, any freedom-to-operate or licensing assessment that excludes Chinese-language filings is working from an incomplete map.
Run a China-inclusive search in EurekaCommon questions about this landscape
The dataset's assignee ranking is led by a mix of specialist water-treatment firms and diversified industrial players, but every one of the top-tracked assignees shows zero filings in the most recent tracked year. That flat latest-year reading is largely an artefact of the roughly 18-month lag between filing and publication, not evidence that these companies have stopped filing. A reliable read on who currently leads requires waiting for the next one to two publication cycles to catch up.
Filings rose from 69 in 2017 to a peak of 79 in 2019, then fell to 44 by 2022 and 23 by 2026. Part of the most recent drop reflects publication lag, but the decline from the 2019 peak through the 2022 midpoint predates that effect and points to a genuine slowdown in new filing. A likely explanation is that core unit operations — biological treatment, aeration, basic oxidation — are already densely claimed, pushing new work toward narrower process-integration and materials claims rather than broad new filings.
China is the largest receiving office by a wide margin, with 464 filings against 205 for the United States, 140 for the European Patent Office, 105 for India, 101 for WIPO/PCT filings and 79 for Australia. This concentration means competitive and freedom-to-operate analysis that only covers US and European filings will miss a substantial share of the active claim landscape. Teams evaluating risk or licensing opportunities in this field should treat a China-inclusive search as standard, not optional.
Beyond the core C02F water-treatment classification, which covers nearly the entire dataset, the largest secondary clusters are B01D separation and filtration processes (154 records), B01J catalysis (75), C12N microorganism and genetic engineering (46) and B01F mixing and stirring (41). This composition shows that differentiation in this field increasingly happens where core treatment claims meet filtration hardware, catalytic chemistry or engineered biological agents, rather than in the base treatment process itself.
Citation counts in a fixed corpus systematically favour older patents, since they have simply had more time to accumulate citations from later filings. The most-cited record in this dataset dates to the early 1990s, and several other highly cited records are 20 to 30 years old, which reflects their role as foundational prior art rather than their current commercial relevance. Use citation rank to identify base art that later claims are drafted against, not as a guide to which technologies matter most today.
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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.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.