Manufacture of Cement from Sewage Sludge

Sludge is an inevitable by‐product of municipal sewage treatment. Its abundance results from rapid industrial growth, and increased treatment requirements create problems of disposal. The disposal problem could be drastically reduced if sludge were to be recycled for economical uses. This paper describes the experimental study on the use of sewage sludge together with limestone and clay as raw materials for making cementitious building material. 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 shows that sewage sludge could be used to produce cement satisfying the strength requirements in the ASTM standard for masonry cement.