Startup landscape: Desalination & advanced water treatment — the companies to watch and why

Global freshwater stress is intensifying faster than infrastructure can adapt. The United Nations estimates that 2.4 billion people live in water-stressed countries, and the World Resources Institute projects that by 2030, global water demand will exceed reliable supply by 40%. Desalination and advanced water treatment have moved from niche applications in arid Gulf states to mainstream infrastructure planning across Europe, the Americas, and Asia-Pacific. The global desalination market reached $21.4 billion in 2025 and is projected to grow at 8.2% annually through 2032, driven by climate-induced drought intensification, population growth in water-scarce regions, and tightening regulations on water reuse and contaminant removal.

Why It Matters

Europe faces acute water challenges that are reshaping policy and investment priorities. The European Environment Agency reported in 2025 that 30% of the EU population experienced water stress conditions during at least one month of the year, up from 20% a decade earlier. Spain, Italy, and southern France endured consecutive drought years in 2023 through 2025, forcing emergency water restrictions affecting agriculture, industry, and municipal supply. The EU Water Reuse Regulation (2020/741), which took full effect in June 2023, sets minimum quality standards for treated wastewater used in agricultural irrigation, creating regulatory pull for advanced treatment technologies across all member states.

The energy cost of water treatment has historically limited desalination deployment. Conventional reverse osmosis (RO) seawater desalination consumes 3.0 to 4.5 kilowatt-hours per cubic meter, making water production costs highly sensitive to electricity prices. At European industrial electricity rates of 0.10 to 0.15 euros per kilowatt-hour, energy alone accounts for 30 to 45% of total desalination costs. Startups attacking the energy challenge through novel membrane chemistries, alternative separation mechanisms, and renewable energy integration are therefore commanding outsized investor attention.

Emerging contaminants add urgency. PFAS compounds, microplastics, pharmaceutical residues, and antibiotic-resistant genes are increasingly detected in surface water and groundwater across Europe. The EU's revised Drinking Water Directive (2020/2184) introduced limits on PFAS, bisphenol A, and other micropollutants, requiring treatment upgrades at thousands of facilities. Conventional treatment plants were not designed for these contaminants, creating substantial demand for advanced oxidation, adsorption, and membrane technologies that startups are well positioned to deliver.

Key Concepts

Reverse Osmosis (RO) remains the dominant desalination technology, using semi-permeable membranes to separate dissolved salts from water under high pressure (55 to 70 bar for seawater). Modern thin-film composite polyamide membranes achieve salt rejection rates above 99.5%. Energy recovery devices, which capture hydraulic energy from the concentrated brine stream and transfer it back to the feed water, have reduced specific energy consumption from 8 to 10 kilowatt-hours per cubic meter in the 1990s to 3.0 to 3.5 kilowatt-hours per cubic meter today, approaching the thermodynamic minimum of approximately 1.1 kilowatt-hours per cubic meter.

Forward Osmosis (FO) draws water through a membrane using an osmotic pressure gradient rather than applied hydraulic pressure. FO operates at lower pressures, potentially reducing fouling and energy consumption for certain feed waters. However, the process requires a "draw solution" with higher osmotic pressure than the feed, and recovering product water from this draw solution often consumes energy comparable to RO. FO has found practical application in niche areas including food concentration, industrial wastewater treatment, and emergency water purification rather than large-scale desalination.

Electrodialysis and Capacitive Deionization use electric fields to remove dissolved ions from water. These technologies are most efficient for brackish water (1,000 to 10,000 mg/L total dissolved solids) rather than seawater, achieving energy consumption of 0.5 to 2.0 kilowatt-hours per cubic meter. Capacitive deionization, using porous carbon electrodes, offers energy recovery during the ion release phase, reducing net energy consumption further. These approaches suit decentralized applications and inland brackish water treatment where brine disposal is constrained.

Advanced Oxidation Processes (AOPs) generate highly reactive hydroxyl radicals to degrade organic contaminants that resist conventional treatment. UV/hydrogen peroxide, ozone/hydrogen peroxide, and photocatalytic systems achieve degradation of pharmaceuticals, pesticides, and PFAS precursors at parts-per-trillion concentrations. Energy consumption ranges from 0.5 to 5.0 kilowatt-hours per cubic meter depending on contaminant load and target removal levels. AOPs are increasingly integrated as polishing steps in water reuse trains following biological treatment and membrane filtration.

Startups to Watch: Membrane and Desalination Innovation

Noria Water Technologies (Netherlands, Series B, $45M raised)

Noria has developed a biomimetic aquaporin-enhanced membrane that integrates aquaporin proteins, nature's water channels, into a thin-film composite RO membrane structure. The result is a membrane achieving 30% higher water permeability than conventional polyamide membranes at equivalent salt rejection, enabling either higher throughput from existing pressure vessels or lower operating pressure and correspondingly lower energy consumption. In pilot testing at the Rotterdam water utility Evides, Noria's membranes demonstrated specific energy consumption of 2.4 kilowatt-hours per cubic meter for seawater desalination, a significant reduction from the 3.2 kilowatt-hours per cubic meter baseline.

The company's manufacturing facility in Delft reached commercial-scale production in late 2025, with capacity to produce 500,000 square meters of membrane per year. Noria's competitive advantage lies in its proprietary stabilization chemistry that extends aquaporin functional lifetime from months (a limitation that plagued earlier attempts by Aquaporin A/S) to over five years under continuous operation.

Desolenator (Netherlands, Series B, $30M raised)

Desolenator combines concentrated solar thermal energy with multi-effect distillation in containerized, modular desalination units producing 10 to 50 cubic meters per day of freshwater. The system requires no external electricity, grid connection, or chemical inputs, targeting off-grid and remote coastal communities, island nations, and humanitarian applications. Each unit integrates solar thermal collectors, heat recovery stages, and automated controls in a standard shipping container footprint.

Operating costs run below 0.01 euros per liter in locations with strong solar resources (above 1,800 kilowatt-hours per square meter per year of direct normal irradiance), compared to 0.005 to 0.015 euros per liter for conventional large-scale RO. Desolenator's modular approach avoids the multi-year construction timelines and $500 million to $1 billion capital requirements of centralized desalination plants, trading economies of scale for speed of deployment and infrastructure independence.

Gradiant Corporation (US/Singapore, Series E, $225M raised)

Gradiant has built a diversified water treatment platform spanning industrial wastewater, desalination, and water reuse. Its proprietary Carrier Gas Extraction (CGE) technology, a humidification-dehumidification process, treats hypersaline brines that conventional RO cannot handle (up to 250,000 mg/L TDS). CGE achieves water recovery rates above 95%, compared to 40 to 50% for seawater RO and 80 to 90% for brackish water RO, dramatically reducing brine discharge volumes.

Gradiant operates over 450 installations across 15 countries, with particular strength in semiconductor fabrication (where ultrapure water requirements create massive wastewater streams), lithium extraction, and petrochemical applications. The company's European expansion, anchored by a regional headquarters in London and partnerships with BASF and TotalEnergies, positions it to serve the EU's industrial water reuse market as regulations tighten.

Startups to Watch: Contaminant Removal and Water Reuse

Oxyle (Switzerland, Series A, $15M raised)

Oxyle has developed a catalytic advanced oxidation process that degrades PFAS compounds, long considered "forever chemicals" due to their resistance to conventional treatment, into harmless fluoride ions. The process uses a proprietary heterogeneous catalyst to generate reactive oxygen species at ambient temperature and pressure, avoiding the extreme energy inputs (greater than 10 kilowatt-hours per cubic meter) required by competing approaches such as supercritical water oxidation or electrochemical oxidation.

In validated third-party testing at the Swiss Federal Institute of Technology (ETH Zurich), Oxyle's reactor achieved greater than 99% destruction of 24 individual PFAS compounds in contaminated groundwater at a treatment cost below 0.50 euros per cubic meter. The company has deployed pilot systems at three European water utilities and secured partnerships with Veolia and Suez for integration into existing treatment trains. Given the EU's proposed near-total ban on PFAS manufacturing and use, demand for effective destruction technologies is set to expand substantially.

374Water (US, NASDAQ-listed)

374Water's AirSCWO (Supercritical Water Oxidation) system destroys organic contaminants, including PFAS, pharmaceuticals, and microplastics, by processing water above its supercritical point (374 degrees Celsius, 221 bar). At supercritical conditions, water becomes a powerful solvent for organic compounds, and oxygen dissolves freely, enabling complete oxidation of contaminants in residence times under 60 seconds. The process generates clean water, carbon dioxide, and mineral ash with no secondary waste streams.

The company's AirSCWO Gen3 units, deployed at US military bases for PFAS-contaminated groundwater remediation, process up to 150 cubic meters per day. European deployment is anticipated following CE marking in 2026, targeting PFAS-contaminated sites in Belgium, the Netherlands, and Germany where industrial contamination from fluorochemical manufacturing has affected drinking water supplies.

Epic Cleantec (US, Series B, $100M raised)

Epic Cleantec installs building-scale water recycling systems that treat blackwater and greywater to non-potable reuse standards (toilet flushing, cooling tower makeup, and irrigation) within commercial and residential buildings. The company's OneWater system combines membrane bioreactor treatment, UV disinfection, and advanced monitoring to produce recycled water meeting California's Title 22 and the EU's water reuse standards.

Active installations in San Francisco, New York, and Austin collectively recycle over 15 million liters per year, reducing municipal water demand by 80 to 95% in equipped buildings. Epic Cleantec announced European market entry in late 2025, targeting water-stressed cities in Spain and southern France where municipal water restrictions have made on-site recycling economically attractive for large commercial developments.

Investment Landscape and Funding Trends

Water technology venture funding reached $3.8 billion globally in 2025, a 45% increase from 2023, according to BlueTech Research. European water startups captured approximately 28% of global investment, up from 18% in 2022, reflecting increased policy support and market urgency. The European Investment Bank's Water Security Initiative, launched in 2024, provides 2 billion euros in concessional financing for innovative water infrastructure, including desalination and advanced treatment projects.

Notable investors shaping the landscape include Breakthrough Energy Ventures, which participated in Gradiant's Series E and has made multiple water technology investments. Xylem's corporate venture arm, Xylem Innovation Labs, has invested in five European water startups since 2023. The Bill and Melinda Gates Foundation's Water, Sanitation, and Hygiene program has funded several advanced treatment startups targeting developing markets, with technology transfer potential to European applications.

Strategic acquirers are active. Veolia, Suez, and Xylem have each completed water technology acquisitions exceeding $100 million since 2023, seeking to integrate advanced treatment capabilities into their municipal and industrial service platforms. This M&A activity provides clear exit pathways for venture-backed startups and signals that incumbents view the innovation coming from smaller companies as essential to meeting regulatory and climate-driven demand.

What Differentiates Winners

The startups gaining traction in this space share several characteristics. First, they reduce energy intensity. Energy represents the largest operating cost for desalination and the largest environmental criticism. Technologies that demonstrably lower kilowatt-hours per cubic meter, whether through better membranes, alternative separation mechanisms, or renewable energy integration, command premium valuations. Second, they address regulatory mandates. Companies targeting PFAS destruction, pharmaceutical removal, or water reuse compliance are solving problems that utilities must address under law, creating non-discretionary demand. Third, they offer modular, scalable deployment. Utilities and industrial customers increasingly prefer containerized, standardized systems that can be deployed in months rather than years, reducing capital risk and enabling phased capacity expansion.

Action Checklist

• Assess your facility's water risk exposure using the WRI Aqueduct Water Risk Atlas, focusing on baseline water stress and projected 2030 conditions
• Evaluate whether the EU Water Reuse Regulation or revised Drinking Water Directive creates compliance obligations affecting your operations
• Screen on-site water recycling economics for facilities consuming more than 50,000 cubic meters per year
• Investigate PFAS contamination exposure in your supply chain and evaluate destruction technologies rather than concentration-based approaches that merely relocate the problem
• Engage with regional water utilities to understand planned infrastructure investments and potential partnership opportunities
• Monitor desalination energy costs at your nearest coastal facilities and evaluate whether declining costs change your water sourcing strategy
• Consider strategic investment or pilot partnerships with water technology startups addressing your specific treatment challenges
• Include water stress scenarios in climate risk assessments and business continuity planning

FAQ

Q: What is the current cost of desalinated water in Europe? A: Large-scale seawater RO desalination in Europe produces water at 0.60 to 1.20 euros per cubic meter, depending on plant size, energy costs, and local conditions. The Torrevieja plant in Spain, one of Europe's largest at 240,000 cubic meters per day, produces water at approximately 0.65 euros per cubic meter. These costs compare to municipal water tariffs of 1.50 to 5.00 euros per cubic meter across European cities, making desalination economically viable for municipal supply in water-stressed regions.

Q: How energy-intensive is modern desalination compared to a decade ago? A: Specific energy consumption for seawater RO has decreased from 4.0 to 5.0 kilowatt-hours per cubic meter in 2015 to 3.0 to 3.5 kilowatt-hours per cubic meter in 2025, a 25 to 30% improvement driven by higher-permeability membranes, improved energy recovery devices, and optimized system design. The theoretical minimum energy for seawater desalination is approximately 1.1 kilowatt-hours per cubic meter, suggesting that further efficiency gains are possible but will require fundamentally new approaches beyond incremental RO improvements.

Q: Can desalination be powered entirely by renewable energy? A: Yes, and increasingly it is. Solar-powered desalination is commercially deployed in the Middle East, Australia, and Southern Europe. The Al Khafji plant in Saudi Arabia (60,000 cubic meters per day) operates entirely on solar power. In Europe, several planned Mediterranean desalination facilities will integrate dedicated solar PV and battery storage to achieve carbon-neutral operation. The intermittency challenge is manageable because desalination plants can operate flexibly, ramping production up during periods of high renewable generation and drawing from storage during low-generation periods.

Q: What are the environmental concerns with desalination brine discharge? A: Seawater RO produces concentrated brine at approximately twice the salinity of seawater. Improperly discharged brine can harm marine ecosystems through elevated salinity, temperature, and residual chemical concentrations. Best practices include dilution with power plant cooling water, diffuser systems that promote rapid mixing, and brine treatment for mineral recovery. The EU's Marine Strategy Framework Directive and Barcelona Convention impose environmental assessment requirements on Mediterranean brine discharge. Emerging zero-liquid-discharge technologies, like those developed by Gradiant, can eliminate brine discharge entirely, though at higher energy cost.

Q: How effective are current technologies at removing PFAS from drinking water? A: Granular activated carbon (GAC) and ion exchange resins remove 90 to 99% of long-chain PFAS from drinking water but only concentrate the contaminants, creating a secondary waste stream requiring disposal or destruction. Nanofiltration and RO achieve greater than 99% rejection of most PFAS compounds but similarly concentrate rather than destroy them. Destruction technologies, including supercritical water oxidation (374Water) and catalytic oxidation (Oxyle), achieve greater than 99% mineralization of PFAS into harmless fluoride ions, representing the most promising long-term solution.

Sources

• United Nations World Water Development Report. (2025). Water for Prosperity and Peace. Paris: UNESCO.
• World Resources Institute. (2025). Aqueduct 4.0: Updated Global Water Risk Indicators. Washington, DC: WRI.
• European Environment Agency. (2025). Water Resources Across Europe: Confronting Water Stress in a Changing Climate. Copenhagen: EEA.
• BlueTech Research. (2025). Water Technology Venture Funding Annual Review 2025. Cork: BlueTech Research.
• International Desalination Association. (2025). IDA Desalination and Water Reuse Handbook 2025. Topsfield, MA: IDA.
• European Commission. (2024). Implementation Report: EU Water Reuse Regulation 2020/741. Brussels: EC.
• Global Water Intelligence. (2025). Desalination Markets 2026: Costs, Technologies, and Opportunities. Oxford: GWI.