Simultaneous waste valorization of sewage sludge and waste glass as raw materials for eco-friendly floor tile fabrication through sintering treatment with alkali agent addition

Abstract

In this study, an alternative approach for the simultaneous waste valorization of sewage sludge (SS) and waste glass (WG) was proposed through eco-friendly floor tile (FT) fabrication with alkali agent addition in sintering treatment. The effects of SS:WG mixing ratio, alkali agent concertation, sintering temperature, and sintering duration on the physical properties of the fabricated FT, including bending strength, bulk density, water absorption, and porosity were investigated. The results indicated that under the optimal conditions of an SS:WG mixing ratio of 1:3, a solid–liquid ratio of 2 g/g, a sintering temperature of 750 °C, and a sintering duration of 60 min, the fabricated FT had a bending strength of 22.5 MPa, a bulk density of 1.31 g/cm³, a water absorption of 17.8%, and a porosity of 18.3%, meeting the CNS-9737 and ISO 13006:2018 for external and internal uses. The carbon dioxide (CO₂) emission of the proposed approach was reduced by more than 50% compared to traditional methods. The results demonstrated that the simultaneous waste valorization of SS and WG could be achieved for resources sustainable utilization. In addition, the eco-friendly fabrication of FT could also be achieved through reducing the required sintering temperature.