China turns desalination waste into resources

October 13, 2026

China has begun trial operations at a large-scale desalination facility in the Caofeidian industrial zone of Tangshan, Hebei province. The innovative project aims to transform concentrated wastewater from seawater desalination into valuable industrial resources while significantly reducing energy consumption and marine pollution.

Developed through a collaboration between Tangshan Sanyou Group and academic researchers, the facility uses a circular economy approach to recover freshwater and chemical raw materials from highly saline wastewater, commonly known as brine.

According to project representatives, the technology can reduce electricity consumption by approximately 60% compared with conventional desalination processes while supplying concentrated salt solutions to nearby chemical manufacturers.

The project could provide a new model for sustainable water management, industrial resource recovery, and environmental protection in China's Bohai Bay region.

Turning Desalination Waste Into Industrial Resources

Traditional seawater desalination technologies, including reverse osmosis, separate freshwater from seawater by removing dissolved salts and other substances.

Although these processes help address freshwater shortages, they also produce concentrated brine containing high levels of salts, minerals, and potentially residual treatment chemicals.

When discharged without appropriate management, this hypersaline wastewater can disrupt marine ecosystems, alter local water chemistry, and threaten aquatic biodiversity.

The new Tangshan facility addresses this challenge by integrating desalination with industrial chemical production.

According to the South China Morning Post (SCMP), the system processes brine using a three-to-one conversion model.

For every three tonnes of concentrated wastewater treated, the facility produces:

• Two tonnes of freshwater suitable for further use.

• One tonne of concentrated brine containing approximately 120 grams of salt per liter.

Instead of releasing the remaining brine into coastal waters, the facility transports it through a 50-kilometer pipeline to a nearby chemical manufacturing complex.

There, the concentrated salt solution becomes a feedstock for producing soda ash, an essential industrial chemical used in glass manufacturing, metallurgy, paper production, textiles, and other sectors.

This integrated process demonstrates how industrial wastewater can become a commercially useful resource rather than an environmental liability.

Advanced membrane technology reduces energy consumption

One of the major challenges in treating concentrated brine is preventing mineral deposits from damaging filtration systems.

As salinity increases, dissolved minerals such as calcium and magnesium can form solid deposits that accumulate inside pipelines and membrane equipment.

This phenomenon, known as scaling, reduces filtration efficiency, increases maintenance requirements, and can shorten equipment lifespans.

To address these problems, researchers at Tangshan Sanyou Group developed a specialized four-stage treatment process incorporating selective membrane technology.

The system removes scaling-related minerals, particularly calcium and magnesium, while retaining sodium chloride in the concentrated solution.

By controlling mineral composition throughout the treatment process, the facility can produce highly concentrated brine without relying entirely on the energy-intensive methods commonly associated with conventional desalination.

The result is a more efficient approach to water recovery and salt concentration that could lower operating costs for industrial facilities.

China reports 60% reduction in desalination electricity use

Zhao Lin, head of research and development at Tangshan Sanyou Group, described the project as one of the largest and most energy-efficient facilities of its type.

Speaking to Science and Technology Daily, Zhao said the new process requires approximately 60% less electricity than conventional approaches for generating an equivalent economic value of 10,000 yuan, or roughly $1,490.

The energy savings are particularly important because desalination and brine concentration can require substantial electricity, especially when treating water with extremely high salt concentrations.

By combining selective membranes, staged treatment, and industrial resource recovery, the Tangshan project aims to improve both the environmental and economic performance of desalination.

Its business model also creates an additional benefit: concentrated salt becomes a useful input for chemical manufacturing rather than a waste product requiring disposal.

Facility could process nearly 100 million tonnes of seawater annually

The Tangshan desalination project is expected to expand significantly as additional development phases are completed.

Once its third phase becomes operational, the facility is projected to process nearly 100 million tonnes of concentrated seawater annually.

At this scale, the project could substantially reduce the volume of desalination-related brine discharged into the Bohai Bay region.

Bohai Bay supports major industrial activities, coastal communities, and marine ecosystems, making pollution prevention an important environmental priority.

However, the project's long-term environmental benefits will depend on operational performance, waste management practices, and the extent to which concentrated brine is successfully reused rather than discharged.

If the technology performs as expected, the facility could demonstrate how large-scale desalination can be integrated with chemical production to support industrial water recycling.

Global interest in brine recycling and resource recovery

China's project reflects a broader international effort to make seawater desalination more sustainable.

Countries facing freshwater shortages are increasingly exploring technologies that recover useful materials from desalination wastewater rather than disposing of concentrated brine directly into marine environments.

Saudi Arabia, one of the world's largest producers of desalinated water, has invested in research and infrastructure focused on brine management and mineral recovery.

Initiatives associated with NEOM and the Saline Water Conversion Corporation (SWCC) have explored technologies such as Zero Liquid Discharge (ZLD) and brine mining.

These approaches aim to recover commercially valuable substances, including sodium chloride, magnesium, and lithium, while reducing liquid waste.

Although many resource-recovery technologies remain in research, pilot testing, or early commercial development, the Tangshan facility represents an example of integrating desalination and chemical manufacturing at industrial scale.

Its direct connection to soda ash production offers a potential economic advantage by creating an established market for recovered salt.

Circular economy solutions could transform the desalination industry

As climate change, population growth, and industrial development increase pressure on freshwater resources, desalination is expected to remain an important part of water supply strategies in many regions.

However, expanding desalination capacity also raises concerns about electricity demand, greenhouse gas emissions, and the environmental consequences of concentrated wastewater disposal.

Technologies that combine freshwater production with resource recovery could help address these challenges.

The Tangshan project illustrates how circular economy principles can connect water treatment and industrial manufacturing, allowing one process's waste stream to become another industry's raw material.

By recovering freshwater, reducing electricity consumption, and supplying concentrated salt to chemical producers, the facility could establish a commercially viable approach to more sustainable desalination.

If its projected efficiency and environmental benefits are confirmed during full-scale operation, the technology may offer valuable lessons for coastal industrial regions seeking to reduce wastewater pollution while improving resource efficiency.