Stabilization of Municipal Solid Waste Fly Ash, Obtained by Co-Combustion with Sewage Sludge, Mixed with Bottom Ash Derived by the Same Plant

Abstract

This study presents an innovative stabilization method of fly ash derived from co-combustion of municipal solid waste and sewage sludge. Bottom ash, obtained from the same process, is used as a stabilizing agent. The stabilization method involved the use of two other components—flue gas desulfurization residues and coal fly ash. Leaching tests were performed on stabilized samples, aged in a laboratory at different times. The results reveal the reduction of the concentrations of heavy metals, particularly Zn and Pb about two orders of magnitude lower with respect to fly ash. The immobilization of heavy metals on the solid material mainly depends on three factors—the amount of used ash, the concentrations of Zn and Pb in as-received fly ash and the pH of the solution of the final materials. The inert powder, obtained after the stabilization, is a new eco-material, that is promising to be used as filler in new sustainable composite materials.

Sustainable Materials and their Contribution to the Sustainable Development Goals (SDGs): A Critical Review Based on an Italian Example

“…The development of new catalysts and smart interfaces can drive CO 2 towards the selective formation of C1-C3 chemicals [ 43 ]. In this frame, the research on sustainable materials can provide novel strategic routes and technologies [ 44 ] (SDG 9). Concerning water, many communities around the world rely on scarce and polluted water sources, often far from the homes and, normally, with the water supply assigned to women, leaving them vulnerable and exposed to different dangers (SDG 5).…”

“…Good mechanical properties of these materials are obtained by using metakaolin and polysiloxane oligomers, making the monolithic artifacts resistant to washings as well as to water adsorption and desorption. Other heavy metals stabilization technologies, based on the use of waste and by-products, were also proposed [ 49 ] to manage, for example, fly ash [ 44 , 50 ]. Finally, it is also interesting to highlight the new emerging water pollutants, typical of the richest countries, like for example pharmaceuticals [ 47 , 51 ].…”

Utilization of Calcium Carbide Residue as Solid Alkali for Preparing Fly Ash-Based Geopolymers: Dependence of Compressive Strength and Microstructure on Calcium Carbide Residue, Water Content and Curing Temperature

“…CCR has been studied for waste gas and wastewater treatment, adsorption of ions [ 8 ], soil treatment [ 9 ], and CO 2 capture [ 10 ]. Some studies [ 11 , 12 , 13 ] have focused on the comprehensive utilization of Ca-containing solid waste, which efficiently solidified the heavy metal and produced an inert and eco-material. Based on these studies, combining the properties of CCR, it is imperative finding a feasible way of reusing CCR to derive environmental, social, and economic benefits from this widespread by-product [ 14 ].…”

Phosphorous and Silica Recovery from Rice Husk Poultry Litter Ash: A Sustainability Analysis Using a Zero-Waste Approach

“…The final aim is to reduce the waste that is landfilled and promote an overall responsible management of materials. New technologies are needed to support the decision makers in developing suitable policies towards the transition to a circular economy [ 7 , 8 ].…”