Chengkou in Shandong aims to build a model marine circular economy

JINAN — In Chengkou, a coastal town in the Bohai Gulf where prosperity was once tied to shrimp harvests, seawater desalinated into fresh water now powers a thriving web of businesses including brewing beer, producing salt, and even heating homes.

This town in Wudi county, East China's Shandong province, stretches along 27 kilometers of coastline and 33,333 hectares of tidal flats, yet receives so little rain that its per capita water resources are less than one-tenth of China's average.

The water scarcity turned into a blessing in disguise in 2021, when China's five-year plan for large-scale seawater desalination opened new doors.

That same year, the Beijing OriginWater Technology Company teamed up with local chemical heavyweight Lubei Group to develop a membrane-based desalination plant in the parched Lubei High-Tech Industrial Park in the county.

The facility can desalinate seawater at a remarkably low cost of 6 yuan ($0.84) per metric ton, thanks to an ingenious circular economy model.

Membrane desalination requires seawater to reach a certain temperature. If the water is too cold, the equipment's efficiency drops or even fails to function. Since Chengkou has low seawater temperatures in winter, companies usually need to purchase steam to heat the seawater.

"The seawater from the cooling tower of the nearby Datang Power Plant remains above 20 C when piped here, making it a viable substitute for steam heating," said Xu Kai, general manager of Shandong Lubei OriginWater Desalination Company.

This approach has helped cut the significant costs of purchasing heat sources.

Overall, the desalination cost for Lubei OriginWater is more than 20 percent lower than the industry average, bringing down water expenses for nearby businesses by over 30 percent, according to Xu.

At a workshop in the industrial park, everything — from salt used for washing fruits and vegetables to industrial salt, drinking water and even beer — originates from the same source: plain seawater.

The brine left after desalination is piped straight to nearby sea salt producers, where it first yields bromine before crystallizing into high-purity salt, and this process reduces both cost and processing time compared to traditional seawater evaporation, said Liu Deting, head of Shandong Chewangcheng Salinization Company.

With Shandong's strong brewing tradition and lively beer festivals, breweries have launched a pilot batch of beer crafted entirely from desalinated seawater, according to Li Xinliang, a local official of Chengkou.

Besides, the heat generated during freshwater production is captured and redirected through community heating pipes, warming several residential blocks in Chengkou each winter.

For the town's long-standing shrimp farming industry, warm seawater processed through the Datang Power Plant's cooling system keeps the ponds above 20 C throughout winter, ensuring a steady harvest, Li said.

The tides still rise and fall, but in Chengkou, they fuel a transformative value chain, driving diverse industries.

Chengkou has attracted investment, accelerating the construction of a series of green and circular marine economy projects here.

Materials firm Longshun uses fly ash, aluminum powder and furnace slag from enterprises in Lubei High-Tech Industrial Park to produce building materials now sold across the Beijing-Tianjin-Hebei region.

Relying on the ocean resources and relevant industries, Chengkou is striving to become a standout example of a marine circular economy, according to Ding Nan, Party secretary of Chengkou township.

Xinhua