Sludge-powered cement in China?

Guangdong, China-based Guangzhou Heidelberg Yuexiu Cement said it began treating sludge this week at its RMB 70 million ($10.2 million) facility designed to turn the wastewater byproduct into a fuel for cement-making.

The company expects the technology to both reduce the coal needed to produce cement, as well as tackle the sludge problem in China.

The plant is expected to treat 600 tons a day of sewage sludge from the city of Guangzhou. The city produces about 950 tons of sludge daily, but projections say the city will produce 2,425 tons daily in 2010 and 3,120 tons daily by 2020.

The problem is country-wide. By 2010, 30 million tons of sludge will be produced per year in China, according to research conducted by China's Ministry of Environmental Protection. Sludge has typically been dumped into rivers and bodies of water, sent to landfills, used to make bricks, or used as compost. Wastewater sludge can contain pathogens, heavy metals and carcinogenic substances.

China began addressing the problem in September by opening its first sludge treatment plant in Dalian, Liaoning Province, using sludge from water treatment facilities to generate gas for the municipal network. 

China is adopting clean technologies from Japanese, U.S and Austrian companies for drying and utilizing sludge (see Euro Tech gets $1.7M waste water contract). Guangzhou Heidelberg Yuexiu Cement is a joint venture of Hong Kong-based Yuexiu Group and Germany's Heidelberg Cement.

The facility is turning industrial and municipal sludge into alternative fuels.

The process takes two steps: one is to reduce the water percentage of wet sludge from 80 percent to 30 percent by utilizing the cement kiln boiler waste heat. The next step involves the mixing of the sludge with half-dried cement material to conserve energy. They expect that every three tons of half-dried sludge can substitute 1 ton of raw coal during the burning process (see Welcome to Sludge Beach).

The sludge treatment test is being conducted in one of China's top commercial and manufacturing regions and the economic center of the Pearl River Delta. Guangzhou is the capital of Guangdong Province in the southern part of China, about 75 miles northwest of Hong Kong.

Last week, the government of Guangzhou unveiled an aggressive new strategy aimed at attracting small and medium companies that work in the environmental sector with corporate income tax waivers (see Guangzhou offers tax waivers to cleantech firms).

The city has also mandated that all buses and taxis will be fueled by liquefied petroleum gas by 2010.