Supercritical Water Oxidation Raises the Bar in PFAS Destruction

A Permanent Solution for "Forever Chemicals"

Collecting PFAS compounds from water and transferring them to a solid waste is not enough on its own; these compounds actually need to be broken down. Supercritical water oxidation (SCWO) stands out as a technology that delivers molecular-level mineralisation and has matured rapidly over the last few years.

How Supercritical Water Works

Above 374°C and 221 bar, water enters the supercritical phase. In this phase, water takes on a structure where liquid and gas properties merge; organic compounds and oxidant react in a fully mixed state. Stable molecules carrying C-F bonds, like PFAS, mineralise within minutes under these conditions. The output consists only of CO2, water and inorganic salts.

Existing Pilot and Full-Scale Plants

Geographic distribution of SCWO deployments worldwide:

• United States: 6 pilot plants (residues from airport firefighting foam)
• Europe: 3 industrial plants (paper and textile by-products)
• Japan: 2 research-scale plants
• Australia: 1 military site pilot
• Canada: 1 municipal wastewater side-stream pilot

Each plant runs at capacities between 1 and 50 cubic metres per day.

Advantages and Cost

Advantages of SCWO:

• Over 99.99 percent mineralisation of stable compounds like PFAS, dioxins and pharmaceutical residues
• No solid waste produced (only salt sludge)
• Reaction heat can be converted into recovered energy
• Multiple pollutant classes managed in a single stage

On the cost side, the process is still expensive: operating costs are reported in the 25–80 USD per cubic metre band. That said, it becomes economically defensible for concentrated streams with high PFAS content (reverse osmosis concentrate, ion exchange regenerant).

Technical Challenges

Technical obstacles to mass deployment of SCWO:

• Corrosion at high pressure and temperature (special alloy requirement)
• Salt deposition and clogging risk
• Reaction heat control
• Detailed training for operating safety

In the last three years, applications of titanium, hastelloy and ceramic composite materials have made notable progress on these fronts.

A Window for Turkey

A PFAS regulation is expected to come into force in Turkey in the coming years. Alongside that, SCWO should be evaluated early on for managing the concentrated streams produced after advanced treatment. Investment in the technology by TÜBİTAK and university research infrastructure can lay the groundwork for Turkey to take on a regional supplier role rather than a technology importer in the medium term.

Market Outlook

The global SCWO market is expected to grow 28 percent annually over the next five years, reaching 1.4 billion USD. Defining customers in the market include the defence industry (military site cleanup), airport operators, water utilities (concentrate management) and specialised waste management firms.