Beijing's water authorities have defended their plan to ease the capital's water shortage by processing seawater from the highly polluted Bohai Gulf, a mainland newspaper reported.
The capital's municipal government has announced a project to build a desalination plan in Tangshan in Hebei province to process one million tonnes of water a day by 2019 to ease Beijing's water crisis.
Wang Xiaoshui, the general manager of the project, told The Beijing News the plan was feasible and dismissed concerns the water would be undrinkable. The water will be treated to strip it of salt, heavy metals and bacteria and will be drinkable straight from the tap.
The plan has prompted public concerns because Bohai, the innermost gulf of the Yellow Sea, has some of China's most polluted waters.
The pollution in the gulf, also known as the Bohai Sea, comes mainly from a large number of coastal industrial zones in Tianjin, Dalian, Weifang and Yantai.
Wang said the desalination plant would be in a location with clean water. After years of testing and monitoring the seawater quality, Beijing's water authorities were confident the water in the Caofeidian district was the cleanest in the Bohai Gulf due to its flow of sea currents.
Construction would cost 7 billion yuan (HK$8.8 billion), excluding a 270-kilometre water-channeling facility that would cost another 10 billion yuan.
Wang admitted that due to the high cost of construction and operation, each tonne of desalinated water would cost 8 yuan - double the current average price paid by Beijing residents. But he argued that water prices in the capital would increase over the next few years, so the cost would be acceptable by the time the desalinated water was available.
However, Professor Hu Yunxia, a desalination specialist at the Yantai Institute of Coastal Zone Research under the Chinese Academy of Sciences, said the retail cost of the water was too high and there needed to be significant room for reduction.
The mainland is short of more than 50 billion cubic metres of water annually, or 8.2 per cent of its annual water consumption of about 610 billion cubic metres. Two-thirds of its cities suffer from water shortages, while close to 300 million people living in rural areas lack access to safe drinking water.
Wang admitted the proposed desalination facility's production capacity of one million tonnes per day was only one-tenth of Beijing's present water consumption, which means the plant alone will not solve the water crisis.
But he said they were preparing to build another plant three times larger, which could satisfy a significant proportion of Beijing's water demand. Coupled with the South-North Water Diversion Project, which will channel one billion tonnes of water from Hubei province to Beijing each year, this could eliminate the capital's shortage.
But the desalination plant would, as a by-product, produce a huge volume of highly salty deposits which the government's State Oceanic Administration warns might disturb the fragile marine environment and ecology of Bohai.
Wang said all the salty by-products would be used by nearby chemical factories and that "not a drop of salty water" would be discharged into the sea.
Still, China lacks experience in building and operating large-scale desalination facilities, so the government must source reliable - but expensive - materials elsewhere.
The Caofeidian plant is heavily dependent on imports - including Norwegian technology and reliable water-filter membranes from the United States.
"All the membranes have to be imported, as well as all the pumps and pipelines," Hu, the desalination specialist, said. "The membranes alone contribute to about 50 per cent of the total cost."
But Hu said the central government was pumping funds into researching and developing Chinese-made desalination technology, which could reduce costs for future facilities.
"Many city governments are interested in desalination, with hundreds of million yuan invested in research and development each year," she said.
Professor Wang Jun, a researcher at the Chinese Academy of Sciences' environmental research centre in Beijing, acknowledged Bohai was polluted, but said that in today's China, it was impossible to find an absolutely safe source of drinking water.