Beijing’s water authorities defended their plan to ease the capital’s water shortage by sourcing seawater from the highly polluted Bohai Gulf.

Wang Xiaoshui, the general manager of the desalination project, said the plan was feasible and dismissed concerns that the water would be undrinkable. The water will be treated to strip it of salt, heavy metals and bacteria.

The water would be “directly drinkable from tap”, Wang, from the Beijing Enterprises Water Group, told The Beijing News in a report today.

The Beijing municipal government recently announced an ambitious plan to build a large seawater desalination facility at the Caofeidian industrial district in Tangshan city – near the Bohai Gulf – to produce one million tonnes of fresh water per day to ease Beijing’s water crisis by 2019.

But the plan immediately prompted public concerns because Bohai, the innermost gulf of the Yellow Sea, has some of the most polluted waters in China.

The pollution in the gulf, also known as Bohai Sea, mainly come from a large number of coastal industrial zones such as Tianjin, Dalian, Weifang and Yantai. Offshore oil rigs also contribute to frequent, large-scale environmental incidents such as the 2011 oil spill from a ConocoPhillips base in Bohai.

Professor Wang Jun, a researcher with the Chinese Academy of Sciences’ (CAS) environmental research centre in Beijing, acknowledges Bohai is polluted, but contends that in today’s China, it is impossible to find an absolutely safe source of drinking water.

Wang Xiaoshui said the sophisticated desalination plant would be in a rare location with clean water. After years of testing and monitoring the seawater quality, Beijing’s water authorities were confident that the water at Caofeidian was the cleanest in Bohai due to the unique flow of sea currents.

Construction of the one-million-tonne-capacity plant 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 Beijing would increase over the next few years, so the cost would be “acceptable” by the time the desalinated water becomes available.

However, professor Hu Yunxia, a desalination scientist with the CAS Yantai Institute of Coastal Zone Research, said the 8 yuan cost was “way too high” and there needed to be significant room for reduction.

Similar plants in places like the Middle East are producing water at 50 US cents, or about 3 yuan per tonne, she noted.

China is short of more than 50 billion cubic metres of fresh water annually, equivalent to 20 million Olympic-sized swimming pools, or 8.2 per cent of its annual water consumption of 610 bcm.

Two-thirds of the mainland’s cities suffer from water shortages, while close to 300 million people living in rural areas lack access to safe drinking water. Beijing has set a national water usage limit of 700 bcm by 2030.

Not the only solution

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 channels one billion tonnes of water from Hubei province to Beijing each year, this could halt the capital’s shortage.

But the desalination plant would, as a by-product, produce a huge volume of highly salty deposits which the State Oceanic Administration warns might disturb the fragile marine environment and ecology of Bohai.

Wang assured that 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 the experience to build and operate a large-scale desalination plant, which means the government had to 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 scientist, said. “The membranes alone contribute to about 50 per cent of the total cost.”

The heavy pollution in seawater also accelerated the ageing of membranes, which need to be replaced frequently.

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 R&D each year,” she said. “The boom is near.”