#China #Qingdao #desalination #seawater #Freshwater

Transforming Seawater: The Key to Water Security in Coastal Cities

In many coastal cities around the world, the irony of living so close to the ocean yet facing severe water shortages is a growing concern. This paradox is especially evident in China, where cities like Qingdao and Tianjin, despite having access to vast amounts of seawater, grapple with critically low freshwater resources. For example, in Qingdao, the per capita water availability is a mere 186 cubic meters per year, which is significantly below the international alarm threshold of 500 cubic meters. The dire situation necessitates innovative solutions to ensure that these urban centers can thrive.

The Role of Seawater Desalination

Desalination—the process of removing salt and impurities from seawater—has emerged as a viable solution to the water crisis faced by these coastal cities. Not only does it provide a sustainable water supply for domestic and industrial use, but it also safeguards the underground water systems from the destructive impacts of over-reliance on limited freshwater reserves. As the extraction of underground water increases, the risk of seawater intrusion rises, threatening the quality and availability of existing freshwater resources.

Take for instance Huni Island in Zhoushan, Zhejiang Province. Historically limited to rainwater as its sole source of water, this community endured regular water shortages that disrupted daily life and industrial activities. However, after the establishment of a seawater desalination plant in October 2025, the situation radically improved. Now, residents enjoy a daily supply of 10,000 tons of freshwater around the clock, ensuring a robust and reliable water source for both households and industries.

Industrial Applications and Economic Benefits

In Tianjin’s Nangang Industrial Zone, the benefits of seawater desalination are equally impressive. Historically, the thermal power plant in this region struggled with freshwater shortages, essential for its operations. With the shift to desalination technology, the plant secured a consistent supply of high-quality industrial water. This transition has not only alleviated the freshwater scarcity but has also resulted in significant cost savings—around 10 million yuan annually—due to reduced water quality issues and decreased pollutant discharges.

Moreover, the concentrated brine that remains after the desalination process is now being utilized in the extraction of potassium, turning a waste product into a valuable resource for agriculture. This integration exemplifies the potential of desalination technology to create a circular economy, where waste materials are repurposed and contribute to sustainable practices.

A Global Necessity

The situation is not unique to China. In various regions, particularly in the Middle East, where only 2% of the world’s renewable freshwater is available, countries have become heavily reliant on desalination. For instance, Kuwait meets 90% of its freshwater requirements through desalination, while Qatar and Bahrain depend entirely on this technology. This critical resource supports not only the local populations but also the region's economic growth and national security.

China has made significant strides in its desalination industry, transitioning from reliance on imported technology to becoming a leader in the field. Through substantial investments and technological advancements, China now produces its own core components, including reverse osmosis membranes, high-pressure pumps, and energy recovery devices, which were previously imported. This self-sufficiency has allowed Chinese firms to participate in international projects, offering solutions to other nations facing similar water crises, such as Egypt and Algeria.

By the end of 2025, China had completed a staggering 167 desalination projects, yielding a total daily output capacity of 3 million tons of freshwater—enough to meet the needs of 15 million people. This revolution in water sourcing not only addresses local challenges but also positions China as a pivotal player in the global water management arena, embodying the commitment to fostering a shared future for humanity.

Conclusion

As cities continue to face the challenges posed by water scarcity, the importance of the innovative applications of seawater desalination technology cannot be overstated. From Huni Island’s transformation to the industrial applications in Tianjin, the ability to harness ocean water is crucial for ensuring water security, economic sustainability, and environmental resilience in the face of rapid urbanization and climate change. Coastal cities globally can draw inspiration from these advancements, turning the abundant ocean into a reliable, strategic resource for generations to come.