Ultrasonic sand desalination device operating beside a seawater desalination plant and DAC pilot on a coastal site.
Muscat, Oman, August 20, 2025
Researchers and companies are advancing ultrasonic sea-sand desalination, a DAC-plus-desalination pilot, and a major financed desalination plant in Oman to secure materials and water for construction and industry. The ultrasonic device uses cavitation to reduce sand salt to 0.04% or lower while cutting water use compared with traditional washing. A pilot linking direct air capture with seawater desalination aims to remove about 1,000 metric tons of CO2 per year and produce fresh water. Separately, $130 million in financing was arranged for a 100,000 m³/day desalination plant west of Muscat to supply utilities and industry.
Key developments are unfolding in construction materials, water infrastructure and carbon removal. A research institute has built an ultrasonic device that strips salt from sea sand while using far less water than traditional methods. Separately, a startup and two Korean utilities have signed a memorandum to pilot a project that pairs direct air capture with seawater desalination. Meanwhile, a major water-services contract in the Middle East has secured financing and will add large-scale desalination capacity.
Sea sand desalination now has an ultrasonic option that meets the national safety limit for salt in construction aggregate and uses less water than conventional washing. A pilot project will test an integrated direct air capture and desalination facility that uses desalination brine as feedstock for a CO2-capturing liquid sorbent and also produces fresh water. And a funded desalination plant in Oman will add 100,000 cubic metres of daily capacity and be operated by a water services firm under a long-term contract.
Sea sand is increasingly used in construction because river sand has become scarce due to environmental rules and overextraction. Salt in untreated sea sand can corrode steel reinforcement in concrete, weakening structures and shortening service life. A government research institute developed an ultrasonic washing device that removes salt efficiently while minimizing water use. The process mixes sand with water at a ratio of one part sand to two parts water, applies ultrasonic energy of 300 watts or greater for about three minutes, and uses cavitation-driven washing—bubble formation and collapse—to sweep particles clean. Tests show the treated sand reaches the recommended maximum salt content of 0.04 percent or below for construction aggregate.
The method is reported to work in confined spaces, offers rapid and precise desalination, and relies on non-contact ultrasonic energy to enhance penetration and particle clearance. Results have been published in a peer-reviewed outlet. Compared with conventional washing—which typically needs around four tons of water to process one ton of sand—the ultrasonic approach is presented as a way to conserve water while meeting strict safety thresholds for reinforced concrete.
A technology firm working on direct air capture (DAC) has signed a memorandum with a state water utility and a wastewater company to build what the partners describe as an integrated facility that combines desalination with carbon removal. The pilot, named Project Octopus, plans to use desalination brine to extract salts that serve as input for a liquid sorbent system that reacts with atmospheric CO2. That trapped CO2 is later mineralized with calcium into a stable, stone-like form, and desalination produces fresh water as a byproduct to serve heavy industry.
The pilot aims to remove about 500 metric tons of CO2 from the air per year and also filter roughly 500 metric tons of stack emissions, for a combined 1,000 metric tons annually. The start-up hopes a full commercial facility could later scale to capture up to 500,000 metric tons per year. The pilot construction budget is estimated at $2–3 million, while a potential commercial plant could cost $100–200 million and would not break ground before late 2026 at the earliest.
Energy use is a critical issue. Both desalination and DAC are energy-intensive; the planned pilot will be grid-connected and therefore use largely fossil-fuel electricity unless cleaner power is provided. That fact draws scrutiny over water security and whether such projects could indirectly support continued fossil fuel use. Proponents argue the dual-purpose design—supplying fresh water to an industrial complex while capturing carbon—could improve environmental outcomes compared with separate facilities, while critics stress the pilot’s capture volumes are small relative to large industrial emitters in the region.
A water-services company secured approximately $130 million of financing for a desalination plant in Oman known as Barka 5. Around 70 percent of that finance is expected from a national export-import bank and local Omani financial institutions, with the remainder financed by a Seoul-based commercial bank. Located about 60 kilometres west of the capital, the plant is scheduled to process 100,000 cubic metres of water per day and to be operated by the water-services firm for a 20-year period under contract with the national procurer. The project is expected to generate substantial revenue for the operator and expand its presence in regional markets.
Switching from river sand to sea sand helps meet material demand where natural river supplies are constrained, but only safe use depends on reliable desalination. Proper removal of salts from sea sand slows corrosion of steel rebar, extending the service life of concrete structures and lowering long-term repair costs and safety risks. For heavy industry, pairing desalination with carbon removal could provide on-site fresh water while offering a route to capture emissions, though the net climate benefit depends strongly on energy sources and scale.
These efforts illustrate contrasting responses to resource and climate pressures: new engineering for materials conservation, integrated pilots that combine water and carbon management, and large, financed desalination plants to meet immediate supply needs. Key next steps include scaling ultrasonic desalination for larger throughput, proving the integrated DAC-desalination process at pilot scale while minimizing energy-related emissions, and completing financed plants on schedule to supply critical water to growing regions. Policymakers, engineers and industry will need to weigh water savings, energy use, lifecycle emissions and cost as these projects move from pilot to commercial operation.
The process mixes sea sand with water at roughly a 1:2 ratio, then applies ultrasonic energy at 300 watts or higher for about three minutes. Ultrasonic waves create cavitation—tiny bubbles that collapse and sweep particles—producing strong particle clearance and non-contact cleansing that removes salts from the sand.
Traditional sand washing often needs about four tons of water per ton of sand. The ultrasonic method uses far less by operating at a one part sand to two parts water mix and relying on ultrasonic action rather than repeated large-volume rinses.
Testing shows the ultrasonic method can reduce salt content to the recommended maximum of 0.04 percent or below, a common regulatory threshold for aggregate used in reinforced concrete.
The main concerns are high energy use and associated emissions when the facility runs on fossil-fuel-based grid power, potential impacts on water security, and whether the approach enables continued reliance on high-emitting industries. Careful planning of energy sources and scale is needed.
The pilot aims to capture about 1,000 metric tons of CO2 per year in total and produce fresh water for local industry at a modest cost of $2–3 million. A commercial-scale facility could cost $100–200 million and target hundreds of thousands of tons of CO2 removal annually if expanded.
The plant will have 100,000 cubic metres per day capacity, is located about 60 km west of a national capital, secured roughly $130 million in finance with a majority from export and local banks, and will be operated under a 20-year contract.
| Topic | Key feature | Data / Value |
|---|---|---|
| Ultrasonic sea-sand desalination | Water use and salt reduction | 1 part sand : 2 parts water; 300 W for 3 minutes; achieves ≤ 0.04% salt |
| Traditional sand washing | Typical water requirement | ~4 tons water per 1 ton sand |
| Integrated DAC + desalination pilot | Pilot capture and cost | ~1,000 tCO2/year combined; $2–3 million pilot cost |
| Commercial DAC aspiration | Potential scale and cost | Up to 500,000 tCO2/year; $100–200 million |
| Barka 5 desalination plant | Capacity and finance | 100,000 m³/day; ~$130 million financing (70% export/local banks, remainder commercial bank); 20-year operation contract |
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