Regardless of what came out of the Copenhagen conference, Premier Wen Jiabao has vowed China would do its best to reduce greenhouse gas emissions.

The clean coastal city of Dalian is already helping to fulfill the government's pledge by treating sludge.

"As we all know, carbon dioxide is an important greenhouse gas. But many may not know that other gases, such as methane, also contributes greatly to global warming. That sludge treatment plant here in Dalian not only bolsters a recycling local economy, but helps reduce greenhouse gas emissions."

Sludge treatment doesn't sound like a very fashionable business. But if not properly treated, sludge can gradually generate methane, a greenhouse gas over 20-times more effective in trapping heat in the atmosphere than carbon dioxide.

Shan Hongguang, Deputy Director, Dalian Urban Construction Bureau, said, "We order all sludge in the city to be transported to one digestion plant for an economic scale. Then after research, we decide to use anaerobic digestion technology, the best among a variety of techniques in treating sludge."

Anaerobic digestion generates biogas with a high proportion of methane, which is captured in these huge green steel tanks.

Dong Jingqing, Chairman of Dalian Dongtai Industrial Waste Treatment, said, "We can collect 4-thousand tons of methane every day. That's equivalent to reduction of 80-thousand tons of carbon dioxide."

(CCTV.com December 21, 2009)