Review of the Reuse Possibilities Concerning Ash Residues from Thermal Process in a Medium-Sized Urban System in Northern Italy

Abstract

This review paper reports a detailed characterization of some combustion or incineration residues and by-products produced in a medium-sized city in Northern Italy. The municipal solid waste incineration (MSWI) generates fly ash, which is a toxic waste. Coal fly ash (CFA) and flue gas desulfurization (FGD) derive from the thermoelectric coal plant located in the same city. Along with these ashes, silica fume and rice husk ash are also considered for the stabilization of fly ash based on their amorphous silica content with the aim to convert them into an inert material. The characterization of all the investigated ashes was performed using different techniques: X-ray diffraction, total reflection X-ray fluorescence, scanning electron microscopy, and transmission electron microscopy. The aim of this work is to describe the reuse possibilities that were proposed for these ashes, which were determined also on the basis of their structural properties. Several possible applications of the investigated ashes are proposed, and the most suitable reuse of stabilized fly ash samples seems to be the production of sustainable plastic composites. This paper shows that the reuse of the by-product materials can allow natural resources to be preserved following the principles of a circular economy.

Simultaneous amorphous silica and phosphorus recovery from rice husk poultry litter ash

“…Eco-materials enhance environmental improvement and respect the sustainability pillars while maintaining accountable performances. [17][18][19][20][21] This work can be classied as a study that addresses possible ways to manage and enhance specic biomass ash, namely rice husk poultry litter ash (RHPLA). As we have previously studied, this waste is mainly composed of K, P, Ca, S, and Si, where the amount of amorphous component is higher than 60%.…”

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

“…The obtained stabilized eco-material is a powder that is very similar to the inert material obtained by using similar treatments but using other by-products (such as silica fume) instead of BA for stabilization. This allows for us to suppose that the obtained eco-materials may be used in some applications, already explored for similar products, as a substitute of natural resources [10,33,35,36]. In particular, it was shown that the obtained eco-materials are biologically safe [37][38][39], opening the interesting opportunity of the investigation of their aquatic toxicity in the next future.…”

“…The obtained stabilized eco-material is a powder that is very similar to the inert material obtained by using similar treatments but using other by-products (such as silica fume) instead of BA for stabilization. This allows for us to suppose that the obtained eco-materials may be used in some applications, already explored for similar products, as a substitute of natural resources [10,33,35,36]. The obtained stabilized eco-material is a powder that is very similar to the inert material obtained by using similar treatments but using other by-products (such as silica fume) instead of BA for stabilization.…”

“…MSWI-FA is generally considered the most problematic incineration waste, due to the presence of leachable heavy metals [3]. Several technologies for MSWI-FA stabilization have been already proposed [4][5][6][7][8] with the aim to promote its reuse [9][10][11]. Even though some recently proposed MSWI-FA treatments were defined as zero-waste technologies [12], they often require MSWI-FA pre-treatments, which need the use of some additional processes and raw materials.…”

New Eco-Materials Derived from Waste for Emerging Pollutants Adsorption: The Case of Diclofenac

“…Sample A and sample B were obtained by mixing under the following relative weight percentage (wt.%): on the one hand, sample A was characterized by 50% Milli-Q water, 30% FA, 9% FGD, 7% CFA, and 4% SF [ 25 ], and on the other hand, sample B was characterized by 48% Milli-Q water, 31% FA, 9% FGD, 7% CFA, and 5% BA [ 19 ]. As a comparison, the last sample (blank sample) was synthesized only by mixing in terms of wt.%: 50% Milli-Q water, 32% FA, 10% FGD, and 8% CFA.…”