The effect of incorporation of a Brazilian water treatment plant sludge on the properties of ceramic materials

We evaluated the feasibility of incorporating sludge from decantation ponds of a water treatment plant (WTP) into a ceramic body used in ceramic brick manufacturing. The sludge grain-size distribution (silt, sand and clay) and the effects of its incorporation on the properties of the ceramic body were studied. Samples were collected during a period of ten months. The chemical and mineralogical compositions of the WTP sludge varied according to the month of sludge production, but the compositions are similar to those of the natural raw material used by the red ceramic industry. Technological tests of ceramic probes showed that this residue can be incorporated into clays used to produce ceramic bricks. The concentration of sludge to be incorporated depends on its properties (grain-size distribution and chemical and mineral composition), but mainly on the properties of the raw material (matrix) used.