Cement Industry Use of Sewage Sludge

Cement Industry Use of Sewage Sludge is yet another method used to dispose of sewage sludge.

A 1993 study mixed sewage sludge with limestone and clay as raw materials for cement. According to the abstract, "A ground mixture of the raw materials was incinerated to produce cement. The effects of mixture compositions, incineration temperatures, and incineration durations on the properties of cement were investigated. From the results, an optimum condition of mixture composition of the raw materials, incineration temperature and duration, and curing condition upon the highest possible strength development of the cement was determined." The study found that the resulting cement satisfied ASTM strength requirement standards for masonry cement.

Other studies and pilot projects have also taken place, particularly in East Asian countries like Japan, Korea, and China. Heidelberg Cement uses sewage sludge in a cement plant in Guangzhou, China that was opened in 2009. Sewage sludge is dried using waste heat from the cement kiln. Then it is placed in the main furnace of the cement kiln and burned as fuel. Last, the residual, non-combustible components of the sludge are used as raw materials in cement production. Heidelberg Cement claims that their process was developed "with the aim of minimising the municipal disposal costs, improving hygiene conditions and reducing emissions in the Guangzhou region."

Related SourceWatch articles

 * Biosolids
 * Sewage sludge
 * Food Rights Network

External resources

 * "Sewage sludge disposal at the Guangzhou cement plant", Heidelberg Cement Global.

External articles

 * "Sewerage sludge - A new raw material for cement production?", Innovations Report, September 27, 2005.
 * J. Monzó, J. Payá, M. V. Borrachero and A. Córcoles, "Use of sewage sludge ash(SSA)-cement admixtures in mortars", Cement and Concrete Research, September 1996.
 * Joo-Hwa Tay and Kuan-Yeow Show, "Manufacture of Cement from Sewage Sludge", Journal of Materials in Civil Engineering, February 1993.
 * T. Taruya, N. Okuno, K. Kanaya, Reuse of Sewage Sludge as Raw Material of Portland Cement in Japan.
 * "From sludge to cement", People's Daily Online, March 10, 2009.