A lingering drought in central and southern China and water shortages in other parts of the nation made Aquatech China, an international fair that was recently held in Shanghai, more timely and relevant than ever before.

Around 800 businesses from all over the world, including big names like BASF, General Electric (GE) and Siemens, participated in the three-day event, which concluded on Friday.

"Seawater desalination is expected to become an effective approach for China's coastal cities to fight water shortage," said Lu Junjun, a client manager with the Dow Chemical (China) Investment Company.

Lu cited a seawater desalination project in the eastern city of Qingdao and a similar project in north China's Hebei Province.

According to Lu, seawater desalination has yet to claim a foothold in China, as the United States and European nations have desalination technology that is much more advanced than China's.

Regardless, seawater desalination is ineffective in combating droughts, meaning that the efficient use of water still poses a problem for many developing countries, according to Kelvin Lau, a regional manager with GE Infrastructure.

Lu said that the combination of desalination and sewage treatment is a better solution for easing water shortages in China's rural areas.

Litree, a water purification company based in south China's Hainan Province, showcased its latest purification technologies at the Aquatech fair. The company supplied 150,000 liters of potable water for 73 million visitors during the 2010 Shanghai World Expo.

According to Chen Lianggang, a water treatment expert and deputy head of the Membrane Industry Association of China, purification processes in most water purification plants end up consuming 5 percent of the water being processed.

Upgrading these plants with new technologies will ensure that 99 percent of the processed water ends up going to consumers instead of being wasted during the purification process, Chen said.

Experts estimate that a purification plant with a daily capacity of 1.5 million liters will produce between 70,000 to 100,000 liters of waste water during the process. However, new technologies have been developed that allow these plants to safely re-purify waste water.

These technologies are currently being used at Beijing's No. 9 Water Purification Plant and the Baoshan Luojing Water Purification Plant in Shanghai.

Kelvin Lau said that waste water treatment technology is a solution for recycling water resources on a smaller scale. However, water control projects and regional coordination efforts should be relied on to shore up water supplies during droughts, he said.