Scientists proved that municipal sewage sludge contains many dangerous pathogens, toxic heavy metals, endocrine disruptors, drains, storm water runoff, hospitals, and industrial plants. Sewage sludge represents an extremely high ecological hazard to the environment. Due to the increasing amount of sludge generated from the wastewater treatments plants a strong demand for environmentally and effective safe reuse has arisen. One potential use of that waste is its incorporation in the production of ceramic tiles. The main aim of present work was to study the possibility of usage of this hazardous waste in floor ceramic tiles industry. A dried sludge waste was added in percentages from 5% up to 35% to a standard floor tile mix, molded, pressed uniaxially at 30 MPa and then fired at temperatures reaching 1150°C for 15 min soaking time. The properties of both green and fired tiles were investigated as function of percent waste added. The vitrification parameters, which are linear firing shrinkage, water absorption, apparent porosity, and mechanical property, were determined and compared with ISO standards. Fired samples of the proposed mixtures were investigated by scanning electron microscope (SEM). It was possible to obtain tiles that abided by ISO standards for maximum addition of 7% sludge fired at 1150°C (for water absorption < 10%), and 10% sludge or 5% sludge for tiles fired at 1150°C and 1100°C, respectively (for water absorption > 10%), which are recommended for both their economic and environmental benefits.
Kiln rollers, which are widely used in ceramic tiles production, are usually subjected to surface grinding to remove the contaminations. The resulted fine powder is considered useless waste and a hazardous source of environmental pollution particularly as it contains health‐threatening fine free silica. In the present paper, the grind waste from kiln rollers was reused as raw material in the fabrication of nanofiltration ceramic membrane. The samples of produced ceramic membranes were formed into disks by adding 15% (by weight) organic binder solution with 2% concentration, then pressed at 35 MPa, dried and fired at temperatures range from 1100°C to 1300°C for 1 hour soaking time. It was found that the best firing temperature to produce nanofiltration ceramic membrane is 1250°C, where the ceramic membrane provides high removal of turbidity and high monovalent, divalent, and trivalent salts separation percentage.
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