SHANGHAI: The city's water authority yesterday launched a scheme to renovate and expand a local sewage treatment plant, claiming it would be the world's largest on completion next year.

The Bailonggang plant in Shanghai's southern suburbs, close to the estuary of the Yangtze River, became operational in 1999 and is currently one of the three largest treatment facilities in the city.

It has the capacity to process 1.7 million cubic m of wastewater a day, but the sanitary level of the processed water is still considered below average.

The municipal government is to spend 2.2 billion yuan ($286 million) to renovate and expand the plant, which when completed in June 2008, will have a daily processing capacity of 2 million cubic m, about one-third of the total amount of wastewater treated in the city every day.

It will be the world's largest sewage treatment plant in terms of processing capacity, the water authority said.

Zhang Quan, deputy general manager of Shanghai Chengtou Corporation, which will carry out the project, said that in the future, the Bailonggang plant be expanded to provide a daily processing capacity of 3.4 million cubic m, making it by far the largest sewage project ever undertaken in China.

The project is also designed to improve the sanitary level of processed water in accordance with national standards. This means that the water, which flows into the Yangtze River after being processed, will be much cleaner, with fewer microbes and chemicals.

For example, the chemical oxygen demand (COD) an index for measuring water quality of the discharged water will be reduced by 162,800 tons per year, Zhang said.

According to its 11th Five-Year Plan (2006-10), Shanghai will have established a sewerage network covering both the downtown area and suburban townships, with a wastewater treatment rate of 80 percent by 2010. The COD amount of the city's total discharged water will be cut by 15 percent.

Yang Xiong, deputy mayor of Shanghai, who attended the project's launch ceremony yesterday said: "The Bailonggang project will be a milestone in the city's sewerage history. The improvements to the discharged water quality will help protect the environment of the Yangtze River, Hangzhou Bay and the East China Sea."

Nearly all of Shanghai's existing sewage treatment facilities are built close to the Yangtze and discharge processed water directly into the river, despite the fact that it is an important source of the city's tap water.

Years of neglect of the city's sewage treatment facilities have had a serious impact on the river, which has been polluted for more than 50 years, environmental experts said.

Sewage and industrial waste produced in cities along its length are the most abundant pollutants dumped into the Yangtze.

(China Daily 05/11/2007 page4)