Marine Sewage Treatment Patents: Leaders, Trends & White Space 2026
- Filing has cooled from its peak. 2017 was the high-water mark at 82 filings, and the 2021-to-2024 window shows a 41% decline; treat 2025 onward as undercounted since publication lags filing by about 18 months.
- No single filer dominates. The leading assignee holds 33 records out of 964 in scope, and the top 5 combined account for just 12.3% of all records — this is a field with a long tail, not a walled garden.
- Biology sits beside separation, not inside it. C02F wastewater treatment covers 81.3% of records, but fermentation, microorganism and bioreactor classes each sit in the single digits, marking where biological routes remain lightly claimed.
Filing growth compares 2021 (32 records) with 2024 (19) — 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 964 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Marine sewage and grey water treatment sits at the intersection of shipboard space constraints, discharge-standard compliance and sludge disposal logistics. The dataset in scope combines 964 published records filed or published between 2015 and mid-2026, drawn from filings that reference biological reactors, discharge standards, sludge disposal, space constraints, type approval or operation reliability alongside marine sewage, grey water or sewage treatment plant terms. Patent families, not raw document counts, are the fairer unit for judging real competitive weight, because families neutralise aggressive continuation practice and multi-jurisdiction refiling that can inflate a single invention’s footprint.
The receiving-office spread points to where compliance and enforcement pressure is concentrated: China leads, followed by the United States, Japan, India, the WIPO PCT route and the European Patent Office. That spread matters for freedom-to-operate work, since a design cleared in one jurisdiction's register says nothing about exposure in another.
Filing trend and technology composition
Two views of the same 964-record dataset: filing activity by year, and where those records sit across the IPC classification system.
Filing trend: a 2017 peak, then a step down
Filings ran to 82 in 2017 and fell through the following years; the 2021-to-2024 window alone shows a 41% decline (32 to 19). The final one or two years in any such trend are always understated because publication typically lags filing by about 18 months, so the apparent recent drop should not be read as the technology stalling — only as the record catching up.
Technology composition: wastewater treatment dominates, biological routes are secondary
C02F (water and wastewater treatment) appears in 81.3% of the 964 records in scope, far ahead of B01D separation processes at 11.4%. Fermentation (C12P), microorganism engineering (C12N), catalysis (B01J), waste-derived fertilisers (C05F), fuels (C10L) and bioreactor apparatus (C12M) each sit between roughly 2.8% and 6.3% — a record can carry several of these classes at once, which is why the shares add to more than 100%.
Shares are the percentage of the 964 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Marine Sewage and Grey Water Treatment with Eureka
This page is one run against one query. Ask Eureka your own question about marine sewage and grey water treatment and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a recent filing
System for reducing and utilizing carbon dioxide generated from sewage treatment plant
Filed by Thezone Environment Technology Consultant and published 2026-07-02, this application couples a multi-stage sewage treatment plant with an algae cultivation device and a gas capture device: carbon dioxide generated during treatment is captured and fed to microalgae cultivated using the plant's treated water, with a nanobubble device handling the treated-water stream.Abstract condensed from the original filing.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6949196B2 | Methods and systems for improved dosing of a chemical treatment, such as chlorine dioxide, into a fluid strea… | 590 |
| 2 | US6045070A | Materials size reduction systems and process | 197 |
| 3 | US20090062581A1 | Methods and apparatus for converting waste materials into fuels and other useful products | 172 |
| 4 | US20050112735A1 | Production of biodiesel and other valuable chemicals from wastewater treatment plant sludges | 149 |
| 5 | US4306978A | Method for lime stabilization of wastewater treatment plant sludges | 114 |
| 6 | US4277342A | Combined biological-chemical detoxification of organics | 106 |
| 7 | US20120018374A1 | Sewage Treatment Process and System | 85 |
| 8 | US4541986A | Process for deodorizing sludge | 83 |
| 9 | US3724542A | Method of disposal of waste activated sludge | 83 |
| 10 | US4370233A | Chemical detoxification of sewage sludge | 82 |
Citation counts inside a searched corpus skew toward older filings that have simply had more time to accumulate citations — read them as a signal of influence on the field, not as a ranking of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three findings from this dataset that change how a competitive or freedom-to-operate review should be scoped.
The leading position is real but not commanding
The single leading assignee holds 33 records, and the top 5 combined reach 119 records — 12.3% of all 964 in scope. That leaves the large majority of filings spread across a long tail of single- and few-filing entrants, which is the pattern of a field still being staked out rather than one already carved up.
Recent-year counts should be read with the lag in mind
Filings fell from 32 in 2021 to 19 in 2024, a 41% decline over that window — the last fully comparable years in the dataset. Years after 2024 will keep filling in as publications catch up, so the apparent slowdown in 2025–2026 is partly an artefact of the roughly 18-month publication lag, not a confirmed drop in activity.
Biological conversion routes are lightly claimed relative to core treatment
C02F wastewater treatment covers 81.3% of the 964 records, while fermentation and enzymatic synthesis (C12P) sits at 6.3% and bioreactor apparatus (C12M) at 2.8%. That gap suggests biological valorisation of sludge and waste streams is documented but far less densely claimed than mainstream treatment process work.
Co-filing is rare and mostly bilateral
Only nine co-assignee pairs appear across the dataset, with the strongest pairing linking two Japanese research and engineering entities at 18 shared records. Beyond that pair, co-filing activity drops to single- or double-digit counts, indicating that most invention in this space is being developed and filed by individual entities rather than joint ventures.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to marine sewage and grey water treatment, with the prior art for and against each one.
Who is filing, and where the gate sits
The assignee ranking covers 100 companies counted in records — not a top-50 or top-100 cut, but the full set the data endpoint returns for this search.
A single leader well ahead of fifth place
The top-ranked assignee holds 33 records against 17 for fifth place and 10 for tenth — a steep early drop-off that flattens into a long tail. That shape favours a challenger strategy of picking a specific sub-branch rather than contesting the leader's core claims head-on.
Several established filers show no latest-year activity
A number of the assignees active earlier in the dataset — including research institutes and engineering firms — show zero filings in the most recent year tracked. Given the roughly 18-month publication lag, this is as likely to reflect filings still working through publication as it is a genuine pause.
China leads receiving-office volume, US and Japan follow
China accounts for 237 filings, ahead of the United States at 190 and Japan at 126, with India, the WIPO PCT route and the EPO each in the 57–68 range. A freedom-to-operate check limited to one or two of these offices will miss the majority of the documented activity.
| Assignee | Recent year | YoY |
|---|---|---|
| Electrochaea GmbH | 0 | — |
| Ebara Research Co., Ltd. | 0 | — |
| Photon Eco Capture (Wuhan) Technology Co., Ltd. | 0 | — |
| Veolia Water Solutions & Technologies Support SAS | 0 | — |
| Toray Engineering Co., Ltd. | 0 | — |
| HaskoningDHV Nederland B.V. | 0 | — |
| Industrie De Nora S.p.A. | 0 | — |
| Toshiba Corporation | 0 | — |
Where to take this analysis
The trends here point to specific next steps depending on whether the goal is defensive clearance or offensive filing.
Scope a freedom-to-operate check by receiving office
China, the US and Japan together carry the bulk of filings; a clearance review limited to a single office will understate exposure given the spread across six major receiving offices.
Run a jurisdiction-scoped searchWatch the under-claimed biological branches
Fermentation, bioreactor apparatus and microorganism classes sit in the single digits by share, well below core wastewater treatment — a candidate area for a first-mover claim before density builds.
Explore white space in EurekaTrack the leader's recent activity, not just its total
A high cumulative count paired with zero latest-year filings can mean a pause or a publication-lag artefact; monitoring going forward resolves which it is.
Set up assignee monitoringCommon questions on this landscape
The dataset's assignee ranking covers 100 companies, with the leading filer holding 33 of the 964 records in scope. The top 5 combined account for 119 records, or 12.3% of all records, which means no single company controls the field. Beyond the leading group, filing activity spreads across a long tail of entities with only a handful of records each, so a competitive review needs to look well past the first few names to get a complete picture.
Filing peaked in 2017 at 82 records and has declined since, with the 2021-to-2024 window showing a 41% drop from 32 to 19 filings. However, publication typically lags filing by about 18 months, so 2025 and 2026 figures in any dataset are undercounted and should not be read as confirmation the field is shrinking. The most defensible read is that activity has stepped down from its 2017 peak but the very latest years are still filling in.
Core water and wastewater treatment processes, classified under IPC C02F, appear in 81.3% of the 964 records in scope, making it by far the dominant classification. Separation processes such as filtration (B01D) follow at 11.4%. Biological and waste-valorisation routes — fermentation, microorganism engineering, bioreactor apparatus, and waste-derived fertilisers and fuels — each sit between roughly 3% and 6%, indicating they are documented but far less densely claimed than mainstream treatment process work.
China leads receiving-office volume with 237 filings, followed by the United States at 190 and Japan at 126. India, the WIPO PCT route and the European Patent Office each fall in the 57-to-68 range. This spread across six major offices means a jurisdiction-limited clearance search is likely to miss a meaningful share of the documented activity, particularly in China and the US.
The composition data suggests yes, particularly in biologically driven routes: fermentation and enzymatic synthesis, microorganism engineering, and dedicated bioreactor apparatus each account for a single-digit share of the 964 records, well below the 81.3% carried by core wastewater treatment classes. Shipboard-specific constraints — space-limited reactor design, type-approval-linked reliability monitoring, and CO2 capture paired with onboard algae cultivation — also appear thinly represented relative to general treatment process claims, making them reasonable areas to investigate before assuming the space is closed.
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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.