Effect of sludge from wastewater treatment processing of a tobacco agroindustry in ceramics matrix

The sludge of a wastewater treatment plant of a tobacco processing agroindustry is a waste material, and although it is not considered a hazardous waste, its disposal must occur in landfills, which causes high costs. Therefore, a thorough study to find a suitable destination for the sludge is necessary. In this work, this sludge and red clay were prepared in different formulations, uniaxial compacted and fired at 950, 1050 and 1150°C to evaluate the effects of the incorporation of sludge to obtain ceramic materials and to verify the potential application in the construction industry. Water absorption increases with sludge content (due the evolvement of gases related to the decomposition of hemicellulose and lignin present in tobacco) and decreases with higher firing temperatures, ranging from 9.55% to 20.10%. Values of mechanical resistance ranged from 7.23 to 1.84 MPa at a firing temperature of 950°C, 7.58 and 1.78 MPa at 1050°C and 6.94 and 3.97 MPa at 1150°C. The results show that ceramic materials obtained are promising in the production of masonry blocks. The use of the sludge reduces the environmental impacts that may be caused by waste and decreases the amount of raw material extracted from nature.