Investigation on the feasibility of resource utilizing drinking water treatment sludge as a pozzolan to prepare cement-based materials

Abstract

The characteristics of four kinds of sludge obtained from different drinking water treatment plants in Australia and China were contrastively analyzed in this study using x-ray fluorescence, scanning electron microscopy, and x-ray diffraction. The conducted SAI test determined the pozzolanic reactivity of drinking water sludge ash (DWSA), which was derived from the grinding and calcination of drinking water treatment sludge (DWTS). The results indicated that the Al2O3 and SiO2 were the main components of DWTS, and the main crystalline minerals in DWTS were quartz, kaolinite, and aluminum sulfate hydroxide hydrate, which can be transformed into the reactive amorphous state after calcination at 800 ºC. Also, the SAI index of DWSA-derived mortar samples met the requirement, indicating a satisfying pozzolanic reactivity. Therefore, the DWTA was possible to be recycled as a pozzolan in cement-based materials.