The cutting-edge technology used to make drinkable tap water in the Expo Garden is expected to be put into wider use in China after the Expo.

The country's first large-scale drinkable tap water facilities are at the Expo, with a total of 158 fountains installed around the Expo Garden to quench thirsty visitors who are not allowed to bring drinks and water into the garden for security reasons.

The free drinkable tap water is being processed by a combined technology of activated carbon absorbing micromolecules of organisms, an ultrafiltration membrane that physically cleans substances, and ultraviolet sterilization. With these technologies, the processed water reaches the international standard for purity and safety, according to Expo authorities.

"Millions of visitors will come to the grand event, and ensuring safe drinking water in the Expo Garden is quite important for us, so we developed a safer, low-carbon technology," said Li Weiying, associate professor of environmental science and engineering at Tongji University, who is in charge of the drinking water research during the Expo.

China's current water treatment sequence, outside of Expo, involves the addition of a coagulant for precipitation, and subsequence filtration and sterilization. "This chemical process may form some potentially harmful substances for people's health," she said.

The water in the Expo Garden comes from the city's three water plants - Linjiang, Yangsi and Nanshi - and is processed by active carbon-ozone technology before flowing into the garden.

"To ensure good raw source water, we adopted a green technology in the process of water purification," she said. "This technology can filter out very well a variety of water impurities from secondary pollution and ensure quality water."

Li said the water reaches the quality standard of the European Union that currently includes more than 200 indicators. "After our repeated tests, the resultant water is completely sterile while domestically-used water is 100 CFU/ml (colong-forming units)," she said.

In standards of turbity, Ph value, and ammonia nitrogen content, the water is also far above the standards stipulated by the European Union.

Li said her research team is still working with local water and related authorities, planning to spread such technology into other fields.

"It can be applied to the city's many public places, such as office buildings and local communities," Li said. "Also it can be used in those rural areas where the water condition is poor."

"These technologies are relatively new, but our technologies can compete with those of foreign countries," she said.

"Very new, very strange, but really convenient," said a visitor Chen Huansheng from Hubei province. "And the taste of water is not different. I think it is good way to protect the environment and it should be used in more cities."

The 158 fountains, each with eight to 12 water outlets and three different heights for adults and children, are available every day during the Expo.

Reports have shown that up to 210 million plastic bottles and 3.5 million tons of tap water can be saved by such facilities during the event.

(China Daily May 20, 2010)