Soil Washing Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled sharply. the field peaked at 12 records in 2017 and growth from 2021 to 2024 sits at -100%, though 2025-26 counts are still filling in under the usual 18-month publication lag.
- The leader board is top-heavy but not locked. the top 5 assignees hold 46.0% of all 100 records and the top 10 hold 66.0%, leaving a long tail of single- and few-filing entrants among the 44 ranked companies.
- Claims cluster hard around soil reclamation. 87.0% of records carry a B09C classification, while adjacent water-treatment (36.0%) and wet separation (25.0%) classes are comparatively open.
Filing growth compares 2021 (1 records) with 2024 (0) — 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 100 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Soil washing and physical separation remediation uses particle-size fractionation, attrition scrubbing and surfactant-assisted washing to strip contaminants from soil and sediment, then manages the resulting fines and process water. The 100 records in scope span 2015 through the 2026 cut-off and mix core remediation-process claims with adjacent water-treatment, separation-equipment and radiation-protection filings. Most activity traces back to a small set of early, heavily cited patents that defined bench-scale treatability testing and on-site monitoring for soil washing operations, several of which are still the most-cited documents in the set today.
The filing curve peaked in 2017 and has since thinned out, with the 2021-to-2024 window showing a full retreat in the growth figure the dataset reports. That pattern, combined with a concentrated but not fully closed assignee list, points to a technology that saw an early wave of process patents and has since settled into narrower, more specialised filings rather than continued broad claiming.
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Filing trend and technology composition
The two views below sit side by side deliberately: one shows when the field filed, the other shows what it filed on. Read the class shares against the full 100-record base, not against each other — a single record can carry several IPC codes.
Filing trend, 2015-2026
Filings peaked at 12 records in 2017 and have declined since; the 2021-to-2024 growth figure of -100% is the clearest complete-year signal in the set. Treat 2025 and 2026 as still filling in rather than as a genuine drop-off, since publication typically lags filing by around 18 months.
IPC subclass composition
B09C (soil and contaminated land reclamation) anchors the field at 87.0% of the 100 records. C02F (water and wastewater treatment) at 36.0%, A62D (chemical protection and detox) at 26.0% and B03B (wet separation of solids) at 25.0% show where remediation claims spill into adjacent processing disciplines, while B07B (sieving and sorting) at 12.0% is the smallest of the tracked classes.
Shares are the percentage of the 100 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Soil Washing and Physical Separation with Eureka
This page is one run against one query. Ask Eureka your own question about soil washing and physical separation and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in the set
US5266494A — Bench scale treatability method for evaluation of soil washing
A process for determining the suitability of soil washing for various types of soils, sludges and other solids is disclosed. The process may be applied to relatively small soil samples which have been contaminated in order to determine the suitability and economics for treating the tested soil using a full-scale soil washing process. The process involves the steps of identifying the contaminated particle size ranges contained in the soil sample, identifying an effective extractant for removing the contaminant of interest, and identifying an effective leachate treatment approach for the particular soil sample of interest.Filed by First Union Bank of Maryland; a bench-scale screening method rather than a full-scale process claim, which is why it sits alongside — rather than blocking — later equipment and chemistry patents.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5436384A | Process for the remediation of contaminated particulate material | 59 |
| 2 | US5292456A | Waste site reclamation with recovery of radionuclides and metals | 58 |
| 3 | US5552051A | Site remediation technology | 47 |
| 4 | US5453133A | Soil remediation | 46 |
| 5 | US5133901A | System and method for on-line monitoring and control of heavy metal contamination in soil washing process | 43 |
| 6 | US5128068A | Method and apparatus for cleaning contaminated particulate material | 41 |
| 7 | US5268128A | Method and apparatus for cleaning contaminated particulate material | 40 |
| 8 | US5303871A | Process for treating contaminated soil | 37 |
| 9 | US5266494A | Bench scale treatability method for evaluation of soil washing | 34 |
| 10 | US5618727A | Bioremediation process design utilizing in situ soil washing | 30 |
Citation counts inside a searched corpus favour older filings; read these as markers of foundational influence, not of current commercial weight.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers actually mean
Three figures do most of the work in this dataset: where the citations concentrate, where the classes concentrate, and how flat the recent filing curve is once the lag-affected years are set aside.
Influence sits with early process patents
The five most-cited records, led by a 59-citation particulate remediation process patent, all predate the field's 2017 peak. They define the bench-scale testing and on-site monitoring methods that later filings still reference, which is a sign of foundational status rather than of a currently contested claim.
Soil reclamation is the crowded core
With 87.0% of records tagged to soil and contaminated-land reclamation, almost every filing in scope touches that class regardless of its specific mechanism. The lower-share classes — B01D separation processes at 13.0% and B07B sieving and sorting at 12.0% — are where equipment-level claiming has been lighter.
The complete-year trend is flat to falling
The peak year was 2017 at 12 records, and the most recent complete comparison the dataset supports, 2021 to 2024, shows -100% growth. Recent-year figures for named leaders also read zero in the latest year, consistent with a field past its filing peak rather than one accelerating.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to soil washing and physical separation, with the prior art for and against each one.
Who holds the ground, and who is still moving
The ranking behind this page covers 44 companies, counted in records — not a top-50 or top-100 cut, but the full ranked field the dataset returns. It is concentrated at the top without being closed off.
One filer sets the pace, but not by a wide margin
The leading assignee holds 15 records against a fifth-place count of 5 and a tenth-place count of 4 — a steep drop after the top position, then a long, gradual tail. That shape suggests one early, prolific filer rather than a stable oligopoly.
Concentration is real but leaves room
The top five assignees combined account for 46.0% of the 100 records in scope. That leaves more than half the field split among the remaining 39 ranked companies plus unranked entrants, which is where new filers can still stake claims without going head-to-head with the leader.
The next five names widen the gate only slightly
Extending from the top 5 to the top 10 adds 20 more points of share, taking combined coverage to 66.0% of all 100 records. Momentum data for several named leaders shows zero filings in the latest year, which is consistent with a leadership group that built its position early and has since gone quiet.
| Assignee | Recent year | YoY |
|---|---|---|
| Institut National de la Recherche Scientifique | 0 | — |
| Westinghouse Electric Corp | 0 | — |
| ENVIT | 0 | — |
| Envit | 0 | — |
| Baker Hughes Co | 0 | — |
| SYNDIAL | 0 | — |
| BRICE ENVIRONMENTAL SERVICES CORP | 0 | — |
| BIOTROL | 0 | — |
Where to take this analysis
The figures above establish the shape of the field. Turning that into a filing or freedom-to-operate decision means going record by record.
Check freedom-to-operate against the foundational patents
The most-cited records in this set, several from the early 1990s, still anchor claim language that later filings build on. Any new process claim in bench-scale testing or on-site monitoring should be checked against them directly rather than assumed expired or superseded.
Run a claim comparison in Eureka →Map the under-claimed branches before filing
Classes like sieving and sorting and separation processes carry noticeably lighter density than the soil-reclamation core, but light density is not the same as empty — a targeted search is still needed before committing claim language.
Explore white space in Eureka →Frequently asked questions
This dataset tracks 100 published records filed or published between 2015 and the 2026 cut-off, spanning core soil-washing process claims and adjacent water-treatment, separation-equipment and radiation-protection filings. The number reflects a defined search string rather than every remediation patent ever filed, so it should be read as a scoped landscape rather than a total count. Filing activity peaked in 2017 at 12 records in a single year and has thinned since.
The ranking behind this landscape covers 44 companies, counted in records, with the leading assignee holding 15 records. The top 5 assignees together account for 46.0% of all 100 records, and that share extends to 66.0% across the top 10 — concentrated, but with more than a third of the field still spread among a long tail of smaller filers. Several of the named leaders show zero filings in the most recent year, which points to an established rather than an actively expanding leadership group.
The complete-year data points to a decline: filings peaked at 12 records in 2017, and the 2021-to-2024 comparison the dataset supports shows -100% growth. That said, patent publication typically lags filing by about 18 months, so the 2025 and 2026 figures in any raw trend chart are still filling in and should not be read as confirmation of an accelerating drop. The safest read is that the field has cooled from its 2017 peak rather than that it has stopped.
Soil and contaminated-land reclamation, IPC class B09C, appears in 87.0% of the 100 records in scope, making it the dominant classification by a wide margin. Water and wastewater treatment (C02F) follows at 36.0%, with chemical protection and detox (A62D) at 26.0% and wet separation of solids (B03B) at 25.0%. Because a single record can carry multiple IPC codes, these shares add up to more than 100% and should each be read against the full 100-record base, not against one another.
US5266494A, filed by First Union Bank of Maryland, claims a bench-scale treatability method: identifying contaminated particle-size ranges, selecting an effective extractant, and identifying a leachate treatment approach before committing to full-scale soil washing. It is a screening methodology rather than a full-scale process or equipment claim, so it does not block equipment design, surfactant chemistry, or fines-management approaches used once a full-scale project is underway. Anyone building a bench-scale suitability test with a similar three-step structure should review its claim language directly rather than assume it only covers historic practice.
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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.