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Turning to the sea for fresh water needs

Turning to the sea for fresh water needs 

People stroll along the beach at Qingdao. The city of Shandong province built a seawater desalination pilot project to save water resources. CFP

China is turning to the sea to solve the growing problem of water shortages afflicting the country and cut utility costs, too.

A pilot project that uses seawater to flush toilets in a residential part of the famous brewery city of Qingdao in Shandong province will be extended after receiving official approval in June.

Another section of the coastal city is experimenting with using seawater in an air conditioning system for apartments, at public gyms and in swimming pools.

Now calls are being made to increase the number and size of desalination plants that treat seawater to provide for more of the country`s needs for fresh water.

Residents of the Haizhiyun neighborhood of Qingdao were the first on the mainland to have their homes fitted with a system that uses seawater to flush toilets.

One of the residents, Li Tong, 62, said he was delighted with the result, which he found more hygienic and economical.

"The salt water is so good," he said. "What`s more important, our monthly expenditure for water usage has been cut by a quarter."

Like 400 of China`s 600-plus cities, Qingdao suffers from acute shortages of water. One-third of household consumption of water is used to flush toilets.

The 800 residents in the pilot project only pay 0.7 yuan per ton for processed seawater, which is about one-third of the average price of tap water in the city.

If 50 percent of Haizhiyun residents - about 1,000 households - used seawater, they would save 378 tons of fresh water and save $110 in water charges every day.

"We are so proud to introduce this eco-friendly project into our community," said Xiao Shengyan, deputy general manager of Qingdao Longhai Group Co Ltd, the developer of Haizhiyun.

The seawater needs to be purified, disinfected and biochemically treated at a plant that cost $878,000. The government paid five-sixths of the price, and Quingdao Longhai Group paid the remainder.

"Although it cost us an extra $140 per household to build dual flushing facilities inside each home, we will see a profit in 10 years, when fresh water will cost a lot more," Xiao said.

Treated seawater is also used in the community swimming pool and can be used in domestic aquariums.

Already, 80 percent of Hong Kong`s population is supplied with seawater for flushing toilets.

"We are facing a shortage of water resources around the world," said Ho Pui-yin, director of the Hong Kong History Resource Center at the region`s Chinese University.

Water from Dongjiang, in Guangdong province, accounts for 70 percent to 80 percent of Hong Kong`s fresh water. Ho said Hong Kong should not remain dependent on that source alone.

He believes the city should make greater use of seawater for daily consumption.

Wang Duo, an associate professor in the College of Chemistry and Chemical Engineering at Ocean University of China believes desalination is the answer.

Desalination plants were introduced in China for the first time in 1958. Now there are more than 20 operations extracting the salt from seawater and purifying it.

Among them are the relatively large-scale Shandong Huangdao and Hebei Huanghua power plants, No 7 Petroleum Factory of China Petroleum Dalian Petrochemical Corp, Tianjin Economic and Technological Development Area, Shandong Yantai City and Hebei Wangtan Power Plant. They produce around 30,000 tons of clean water a day.

Most enterprises with an annual production capacity at more than 100,000 tons cooperate with foreign enterprises such as General Electric and Befesa.

The ambitious Spanish developer Befesa made inroads in Qingdao`s market by constructing a seawater reverse osmosis plant in 2007.

At present, the daily output of China`s desalinated water accounts for .003 percent of the world`s total output. Authorities say the target for 2010 is to produce up to 1 million tons per day.

China is regarded by the United Nations as one of the 13 most water-deficient countries in the world. As supplies dry up, the cost of water will rise.

The advancement of seawater desalination technology has brought down its high cost. However, China relies largely on foreign equipment and expertise.

Some industry insiders believe that overseas investors should be encouraged to undertake desalination projects in China.

According to the China Seawater Desalination Annual Report (2007), foreign desalination equipment providers will control 50 percent of China`s market within the next three to five years.

"The government should have a policy to subsidize and offer tax incentives to domestic and overseas operators to encourage them to undertake the risk in this high-cost industry," said Kang Jian, an official from the State Oceanic Administration.

In Hong Kong, it is also suggested the government set up a medium-sized desalination demonstration plant to supply salt-free water to a small community as a foundation for further studies.

But seawater desalination is proving more costly than expected. A spokesman for the city`s Water Supplies Department said the unit water production cost of using Dongjiang water is about HK$6 per ton versus about HK$10 per ton for desalinated water.

If water shortages get worse, that ratio is likely to change.

In Qingdao, seawater is being used for air conditioning in the city`s Economic and Technological Development Area. The system uses deep ocean water to provide air conditioning for 74,000 sq m of coastal apartments. It will save 40 percent of the cost of traditional systems.

If this experiment is deemed a success, it will also be extended.

Date:2009-8-17 8:03:00     
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