Full coverage: G20 Hangzhou Summit

The G20 summit in Hangzhou is just over two weeks away. One of the big issues on the agenda will be the 2030 Agenda for Sustainable Development Goals. The ambitious plan includes battling water pollution and addressing water shortages. A two-hour drive from Hangzhou is Shanghai's biggest waste water treatment plant. CCTV's reporter Hu Nan visited there and filed this report about the municipal government's efforts to improve water quality, in tap water supplies and in waste water disposal.

Shanghai is one of China’s biggest cities, and its 20 million residents produce 7 million tons of domestic and industrial waste water each day.

“As Asia's biggest waste water treatment plant, a third of Shanghai's total waste water is processed at the Bailonggang waste water treatment plant. The processed water is safely discharged into the sea, but the real problem lies beneath the surface. And that is the more than one hundred thousand tons of sewage sludge produced every year," Hu Nan said.

The sewage sludge is a side-product of waste water cleaning procedures. It's actually the deposit of microorganisms after waste water has been cleaned with chemical additive agents. The amount of the sludge is substantial.

A technical expert from Bailong Gang waste water treatment plant, said, “The sewage sludge produced every day can fill 50 trucks with a 20-ton load capacity. That’s a huge amount for sludge disposal. In the past we spread it on farmland as a fertilizer. But now, after industry in Shanghai developed greatly around the millennium, the chemical substances in the water mean it's no longer suitable for farming."

The Shanghai municipal government has invested over 1 billion yuan to develop facilities to utilize the sewage sludge. The plant produces 40-45 thousand cubic meters of methane a day, and bricks made of compressed sludge are taken to a disposal spot to be buried. And scientists are looking for further uses.

“By 2020, the limited land resources will spare no room for sludge disposal, so we're developing new solutions. Firstly, the intense heating will lower the moisture of the sludge to nearly zero percent and kill the bacteria; then the ashes will be compressed into hard bricks for construction use. This solution saves the land resources and meets with our environmental protection goals,” said the technical expert.

Phase-2 of the processing line is under construction to service all waste water treatment plants in Shanghai. But less than 2% of sewage sludge in China is utilized, comparing to a 75% rate in Great Britain.