Zero Liquid Discharge Membrane Patents: Leaders & Filing Trends 2026
- Filing activity peaked in 2021 at 9 families then dropped to zero at the 2022 midpoint before climbing again — a pattern more consistent with a stalled early wave than a steadily maturing field.
- Two most-cited families share one root the top two cited records are both titled "Multi-use high water recovery process," filed years apart — most of the field's influence traces to a single technical lineage.
- Filing is split almost evenly across two IPC subclasses C02F (19 records) and B01D (17 records) overlap heavily, showing that treatment-process claims and separation-hardware claims are being filed by the same actors rather than by distinct specialists.
What this landscape covers
Zero liquid discharge (ZLD) membrane filtration sits at the intersection of high-recovery reverse osmosis, brine concentration and membrane pretreatment — technologies aimed at eliminating liquid waste streams entirely rather than merely reducing their volume. This landscape draws on 31 patent families published between 2015 and mid-2026 that explicitly claim ZLD, brine minimization or high-recovery membrane processes. Publication typically lags filing by around 18 months, so the most recent filing year in this dataset is understated relative to actual filing activity.
The dataset is small enough that individual filings move the picture: a single prolific assignee's activity in any one year can shift the visible trend line. That makes assignee-level filing history, not just aggregate counts, the more reliable read on where the field is heading.
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Filing trend and technology composition
Two views of the same 31-family dataset: how filing activity has moved year over year, and how those families split across the IPC subclasses that define the field's technical core.
A restart, not a steady climb
Filings were absent in 2017, rose to a peak of 9 in 2021, then fell back to zero at the 2022 midpoint before resuming growth toward 2026. That shape points to a first wave of filing driven by a small number of assignees, a pause, and a second wave now building — rather than continuous, broad-based adoption.
C02F and B01D carry the field almost equally
Water and wastewater treatment (C02F, 19 records) and separation processes such as filtration (B01D, 17 records) account for nearly all of the classified activity, with substantial overlap. Filers are claiming both the process chemistry and the membrane hardware in the same applications, which narrows the room for a claim that addresses only one side of that boundary.
Shares are the percentage of the 31 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Zero Liquid Discharge Membrane Filtration with Eureka
This page is one run against one query. Ask Eureka your own question about zero liquid discharge membrane filtration and every answer comes back with the patent numbers behind it.
Try EurekaThe records other filings cite most
WO2020179594A1 — Zero liquid discharge system
Filed by Toyobo, this application chains a biological treatment stage, a membrane pretreatment stage to remove clogging components, a reverse osmosis concentration stage, and a further brine concentration stage into a single ZLD system aimed at handling waste water with both organic and inorganic content more efficiently than prior multi-stage designs.Abstract condensed from the original filing for readability.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US8679347B2 | Multi-use high water recovery process | 24 |
| 2 | US20110315631A1 | Multi-use high water recovery process | 14 |
| 3 | WO2020179594A1 | Zero liquid discharge system | 13 |
| 4 | CN202208671U | 含盐废水零排放回收系统 | 6 |
| 5 | WO2011147019A1 | Multi-use high water recovery process | 6 |
| 6 | CN211311217U | 零液体排放系统 | 5 |
| 7 | WO2025029830A1 | High performance composite membranes | 1 |
| 8 | CN114105269A | 用于逆渗透膜预处理的二氧化硅去除剂 | 1 |
Citation counts favour older records simply because they have had more time to accumulate citations within the searched corpus; treat this as a measure of influence on the existing art, not of current commercial relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Publication numbers are shown where the record carries one (8 of 8 rows); 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 the dataset that bear directly on where to file next and what to watch.
The field has restarted once already
A peak in 2021 followed by a complete drop at the 2022 midpoint suggests the first filing wave was concentrated in a handful of assignees rather than broad industry adoption. The renewed climb toward 2026 is a second wave, still early enough that its final shape is not yet visible in published data.
Influence traces to one lineage
The two most-cited records in the set share the same title, "Multi-use high water recovery process," filed at different times — meaning the field's foundational prior art is narrower than the 31-family count suggests. New filings in high-recovery membrane processes should expect this lineage to surface in any freedom-to-operate search.
Filing is dispersed, not concentrated in one office
No single receiving office dominates: the United States leads narrowly, PCT filings via WIPO are close behind, and China, Europe, Australia and Canada each carry a small but real share. That spread implies assignees are hedging jurisdiction rather than committing to one primary market.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to zero liquid discharge membrane filtration, with the prior art for and against each one.
Who is filing, and where the gate sits
The assignee list is short and uneven: one academic filer is active in the most recent year, while several previously visible names show no recent-year activity at all.
One academic assignee carries the current wave
The University of California Regents is the only entity in this dataset with recorded activity in the most recent year, at 3 families. Every other tracked assignee — including established industrial names — shows zero filings in that same window, which either reflects a genuine slowdown or a publication-lag gap not yet visible in the data.
Legacy high-recovery IP still anchors the art
The most-cited record in the set, "Multi-use high water recovery process," and its earlier-published counterpart form the citation backbone that later ZLD filings build on. Any new entrant's claims in RO brine concentration should be checked against this lineage first.
Toyobo's system-level claim sets the integration bar
Toyobo's WO2020179594A1 claims a full biological-to-brine-concentration chain rather than a single unit operation, which raises the bar for competitors trying to patent isolated pretreatment or concentration steps within the same process flow.
| Assignee | Recent year | YoY |
|---|---|---|
| The Regents of the University of California | 3 | — |
| Ecolab USA Inc. | 0 | — |
| AL SAMADI RIAD A | 0 | — |
| Toyobo Co., Ltd. | 0 | — |
| Jiangsu Zhongsheng High-Tech Industry Co., Ltd. | 0 | — |
| Qatar Foundation for Education, Science and Community Development | 0 | — |
| AL SAMADI RIAD DR | 0 | — |
Where to take this analysis
This landscape identifies the pattern; the next step is applying it to a specific claim set or freedom-to-operate question.
Check a draft claim against the lineage
Run a candidate claim in RO brine concentration or membrane pretreatment against the citation lineage anchored by the two most-cited families in this set before drafting further.
Explore in Patsnap Eureka →Track the second filing wave as it publishes
Given the 2022 gap and the renewed climb toward 2026, monitor new publications from the University of California Regents and any new entrants closely over the next 18 months.
Set up monitoring in Patsnap Eureka →Common questions about this landscape
In this dataset, ZLD membrane filtration covers filings that explicitly claim zero liquid discharge, brine minimization, or high-recovery membrane processes, typically combined with reverse osmosis brine concentration or membrane pretreatment steps. It is a systems-level term rather than a single unit operation, so filings often span multiple treatment stages in one application. Practically, that means a search on this topic pulls in both process-chemistry claims and membrane-hardware claims, since assignees frequently file both together, as shown by the overlap between the C02F and B01D subclasses in this dataset.
The dataset shows filings rising to a peak of 9 in 2021 and then falling to zero at the 2022 midpoint, which is more consistent with a concentrated first wave from a small number of assignees than with a broad, sustained trend. Publication lag of roughly 18 months also means 2022 and later years are undercounted in any dataset pulled before those filings fully publish. Readers should treat the apparent 2022 gap as provisional rather than a confirmed slowdown in R&D activity.
The University of California Regents is the only assignee in this dataset with recorded filings in the most recent year, at 3 families, while other tracked assignees including Ecolab, Toyobo, and several others show no recent-year activity. The most-cited legacy filings in the space are tied to a "Multi-use high water recovery process" lineage rather than to any single currently active filer. This suggests the field's foundational IP and its current filing activity are held by different parties, which matters for freedom-to-operate assessments.
WO2020179594A1, filed by Toyobo, claims an integrated zero liquid discharge system that chains biological treatment, membrane pretreatment for clogging removal, reverse osmosis concentration, and a further brine concentration stage into one process. Because it claims the full chain rather than an isolated step, it raises the practical bar for anyone trying to patent a single unit operation that fits within the same overall process flow. Anyone designing a competing or complementary ZLD system should map their claims against this system-level scope before filing.
Based on the IPC composition and assignee activity in this dataset, sub-areas such as selective scaling-ion removal pretreatment, non-thermal brine crystallization coupling, and fouling-resistant pretreatment membrane coatings show comparatively little dedicated claim activity relative to the dominant C02F and B01D subclasses. These sit adjacent to well-claimed system-level patents like WO2020179594A1 but are not claimed as standalone inventions in this dataset. That gap does not guarantee patentability, but it does indicate less crowded claim space worth a closer freedom-to-operate check.
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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.