Water Reuse & ZLD Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled since a 2020 peak of 8 records, with the 2022 midpoint at just 2 — this is a flat-to-declining filing curve, not a growth curve.
- C02F carries all 93 families, but B01D separation (28) and three thermal-power IPC groups (F01K, F22B, F22D, 10 each) show the field is really about coupling separation to steam/heat recovery.
- The most-cited prior art is a single produced-water steam lineage, with US20080110630A1, US7591309B2 and WO2005054746A2 all describing the same high-pressure-steam-from-produced-water method across three publications.
What this patent set actually covers
The corpus sits at the intersection of C02F water/wastewater treatment and B01D separation processes, filtered to brine concentration, evaporator-crystallizer, energy intensity, scaling control and salt recovery language. Every one of the 93 families touches C02F, but a third also carry B01D classification, and three separate steam/boiler subclasses — F01K, F22B and F22D — appear at equal weight (10 records each). That pattern points to a technology area defined less by membranes alone and more by the pairing of separation with thermal energy recovery, the combination that zero liquid discharge systems depend on to close the water loop economically.
Filing offices skew toward the United States and India, with WIPO PCT filings a close third, and Australia, Canada and China rounding out the top receiving offices at similar volumes. That spread suggests applicants are pursuing water-stressed and industrial-heavy jurisdictions in parallel rather than concentrating filing strategy on a single home market.
Let an AI agent run this analysis on your own technology
Pick a task. Every answer cites the patents behind it.
Filing trend and technology composition
Two views of the same 93-family dataset: how filing activity has moved year over year, and which IPC subclasses carry the claim volume.
A peak that has not been repeated
Filings rose from 1 in 2017 to a peak of 8 in 2020, then fell back — the 2022 midpoint of 2 confirms this is a flat-to-declining curve rather than sustained growth. Because publication lags filing by roughly 18 months, the final one or two years in any such trend will always look thinner than they eventually turn out to be, but the pattern predates that lag effect.
Separation and thermal recovery share the claim space
C02F anchors every record; B01D (28), E21B well/drilling technology (18), and the equal-weighted F01K/F22B/F22D thermal trio (10 each) show that produced-water and steam-integrated approaches are as central to this dataset as membrane separation itself.
Shares are the percentage of the 93 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Water Reuse and Zero Liquid Discharge with Eureka
This page is one run against one query. Ask Eureka your own question about water reuse and zero liquid discharge and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art doing the most citation work
Enhanced brine concentration with osmotically driven membrane systems and processes (US20170369337A1, Oasys Water)
The invention generally relates to osmotically driven membrane systems and processes and more particularly to increased brine concentration for zero liquid discharge using osmotically driven membrane systems and processes and the related draw solute recovery techniques for the osmotically driven membrane systems and processes.Filed by Oasys Water, published 2017-12-28. Framed around osmotic membrane brine concentration as a route to zero liquid discharge, with draw-solute recovery as a distinct claimed sub-process.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20080110630A1 | Method for Production of High Pressure Steam from Produced Water | 94 |
| 2 | US7591309B2 | Method for production of high pressure steam from produced water | 80 |
| 3 | US20150315055A1 | Water Treatment Process | 56 |
| 4 | WO2014088826A1 | Water treatment process | 39 |
| 5 | WO2005054746A2 | Method for production of high pressure steam from produced water | 32 |
| 6 | US5656161A | Salt basket for crystallizer and method of use in zero liquid discharge industrial facilities | 30 |
| 7 | US5472622A | Salt basket for crystallizer and method of use in zero liquid discharge industrial facilities | 29 |
| 8 | US20190169056A1 | Salt production from wastewater | 23 |
| 9 | US20170028348A1 | Osmotic separation systems and methods | 18 |
| 10 | WO2015157031A1 | Osmotic separation systems and methods | 15 |
Citation counts reflect influence within this searched corpus and favour older filings; treat them as a signal of foundational claim territory, not of what is commercially current.
Each row carries its publication number; clicking a row searches Eureka by that number.
Put your own technology through the same analysis
Eureka on the web
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →MCP server & REST API
When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →What the numbers mean for a filing decision
Three read-throughs from the trend, classification and citation data before you decide where to place claims.
The growth phase has already passed
A peak of 8 families in 2020 followed by a drop to 2 by the 2022 midpoint indicates this is not an expanding filing category right now. New entrants should treat the space as claim-dense in its core rather than wide open, even allowing for the 18-month publication lag understating the last year or two.
ZLD is a systems problem, not a membrane problem
Equal weighting across steam power (F01K), steam generation (F22B) and boiler feed-water control (F22D) alongside separation (B01D) shows applicants are claiming the energy-recovery loop, not just the separation step. Claims that isolate a membrane or crystallizer without addressing the heat-integration side are competing in a narrower slice of the art.
Produced-water steam generation is the foundational claim territory
The five most-cited records in this corpus are variants of the same produced-water-to-high-pressure-steam method, published across three separate documents. Anything touching steam generation from produced or reject water sits downstream of this lineage and should be checked against it directly.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to water reuse and zero liquid discharge, with the prior art for and against each one.
Who is filing, and where the field is open
Assignee activity here is comparatively dispersed, with several organisations holding co-filed pairs rather than one company dominating volume.
Filing is collaborative in pockets, not centralized
The strongest co-assignee pairs recur at 2-3 shared families each, rather than any single entity accumulating a large solo portfolio. That points to joint ventures and inventor-team continuity as a more useful signal than raw assignee counts.
No assignee is currently active in the newest filing year
Every tracked assignee shows zero filings in the most recent year in this dataset. Given the roughly 18-month publication lag, this likely understates real activity rather than confirming an exit from the space, but it means recent competitive-intelligence signal from filing dates alone is thin.
Filing strategy spans water-stressed markets in parallel
The United States and India lead, with WIPO PCT filings close behind and Australia, Canada and China at similar secondary volumes. This is consistent with applicants targeting industrial and water-scarce jurisdictions concurrently rather than sequencing a home-market-first strategy.
| Assignee | Recent year | YoY |
|---|---|---|
| Enel Produzione | 0 | — |
| Water Technologies International LLC | 0 | — |
| Oasys Water LLC | 0 | — |
| CHATTERJEE TAPAS | 0 | — |
| AINEC Co., Ltd. | 0 | — |
| Chatterjee Tapas | 0 | — |
| TAPAS CHATTERJEE | 0 | — |
| MOSTI CLAUDIO | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether you are clearing a filing, tracking competitors, or scoping new claim territory.
Run a freedom-to-operate check against the produced-water steam lineage
If your work touches steam generation from produced, reject or brine water, the top-cited family in this corpus is the first thing to clear against, not an afterthought.
Search this corpus in EurekaScope claims around heat-integration, not just separation
The equal weighting across F01K, F22B and F22D suggests examiners and competitors alike are already treating energy recovery as claimable territory alongside the separation step.
Explore IPC breakdowns in EurekaWatch co-assignee pairs for joint-venture signals
Recurring co-assignee relationships are a more current signal than raw filing counts, given the flat recent-year momentum across individual assignees.
Track assignees in EurekaCommon questions on water reuse and ZLD patents
In this corpus, zero liquid discharge (ZLD) filings specifically claim eliminating liquid waste streams entirely, typically through brine concentration followed by evaporation or crystallization to recover solids and clean water. Water reuse claims are broader and cover recycling treated water for further use without necessarily eliminating all liquid discharge. The search terms used here — brine concentration, evaporator-crystallizer, scaling control, salt recovery — sit specifically on the ZLD side of that distinction, though many families claim both concepts together as a system.
Filing activity in this dataset is dispersed rather than dominated by one company, with several organisations appearing in co-assignee pairs of two to three shared families rather than large solo portfolios. Oasys Water appears as a notable filer with membrane-based brine concentration claims. The most-cited prior art, however, traces to a single produced-water steam generation lineage published across three separate documents, which is worth checking regardless of who currently leads by filing volume.
Not currently, based on this dataset. Filings peaked at 8 in 2020 and had fallen to 2 by the 2022 midpoint, a flat-to-declining trend rather than sustained growth. Publication lag of roughly 18 months means the most recent one or two years will always look thinner than they eventually prove to be, but the decline from the 2020 peak predates that effect and reflects a real slowdown in new filings.
Based on IPC classification density, scaling-control chemistries for crystallizer feeds, draw-solute recovery in osmotic brine concentration, and salt-recovery valorisation from concentrated brine all sit adjacent to the dense core claim territory without matching filing volume. Boiler feed-water control integrated directly with ZLD loops is another area with equal-weighted but comparatively low absolute filing counts (10 records) relative to the core C02F classification. These are reasonable areas to scope a first claim rather than areas already saturated.
That filing, from Oasys Water, claims osmotically driven membrane systems specifically for increased brine concentration toward zero liquid discharge, including draw-solute recovery techniques as part of the claimed process. It does not block brine concentration approaches using other separation mechanisms such as thermal evaporation, mechanical vapor compression, or non-osmotic membrane methods. Anyone building specifically on forward-osmosis or pressure-retarded-osmosis brine concentration with draw-solute recovery should review its claim scope directly rather than assume freedom to operate.
Research Water Reuse and Zero Liquid Discharge in depth with Eureka
Go past this page: query the whole water reuse and zero liquid discharge corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
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.