Life cycle assessment for the production of MSWI fly-ash based porous glass-ceramics: Scenarios based on the contribution of silica sources, methane aided, and energy recoveries. (15th February 2023)

• Record Type: Journal Article
• Authors: Barracco, Francesco; Demichelis, Francesca; Sharifikolouei, Elham; Ferraris, Monica; Fino, Debora; Tommasi, Tonia
• Is Part Of: Waste management. Volume 157(2023)
• Page Start: 301
• Page End: 311
• Publication Date: 2023-02-15
• Subjects: LCA -- Fly ash -- Bottom ash -- Municipal solid waste -- Climate change -- Circular economy; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2022.12.013
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: MSWI thermal energy recovery greatly benefits FA vitrification sustainability. Vitrification of incineration residues makes them safe to produce new products. Glass cullet as silica source most sustainable option among studied scenarios. Silica source type affects all analyzed impacts more than energy requirement. Despite some drawbacks, sensitivity scenarios could lead to new studies. Abstract: Municipal solid waste (MSW) production in the world has increased by 60 % in recent years. Incineration of MSW reduces their volume in conjunction with energy recovery. Incineration produces two residues, namely bottom ash (BA) and fly ash (FA), with high concentration of heavy metals and organic pollutants, especially for FA, making them an environmental concern. Vitrification is a costly, highly safe high temperature treatment, ensuring encapsulation of heavy metals. FA vitrification requires a source of silica to be able to get vitrified. In this study, we have proposed valorizing treated (vitrified) FA through the production of porous glass-ceramics, subsequently to MSWI. The entire process, from incineration to glass-ceramics production, was evaluated for several scenarios by Life Cycle Assessment (LCA) using Sima Pro 9.0. Three main scenarios were analysed; each one considering a different silica source: bottom ash (BA), glass cullet (G) and silica sand (S), and for each scenario, three thermal recovery subscenarios were assumed: no thermal recovery used to heat FA prior to vitrification (N), heating FA prior to vitrification using incineration gases thermal recovery (T) and methane-combustion-aided thermal recovery, which exploits methane combustion to further increase the gases temperature (M). Results proved that vitrification was a technically feasible and environmentally-energetically sustainable technology. The result indicates that the most eco-sustainable scenario was using bottom ashes as a silica source together with methane-combustion-aided recovery: 0.467 kgCO2, eq, 5.83 × 10 -8 carcinogenic-CTUh and 9.26 MJ required per kg of glass-ceramics produced.