Waste Incineration Bottom Ash Research Articles

Analysis of pore structure characteristics of MSWI bottom ash micro powder concrete

Municipal solid waste incineration (MSWI) bottom ash is a type of bulk waste. Its potential activity can be better harnessed after it is ground into a fine powder, leading to reduced carbon emissions. This paper investigates the pore structure of MSWI bottom ash micro powder concrete and its impact on mechanical properties. Standard tests were conducted to evaluate the mechanical properties of MSWI bottom ash micro powder concrete with four blending ratios under three water-binder ratios. Subsequently, a mercury intrusion test was performed to determine its internal pore structure characteristic parameters. Remaining specimens from the macroscopic test were sampled, and concrete specimens were observed using a high-power electronic environmental scanning microscope to analyze morphological characteristics at various multiples and curing ages. The results indicate that the pore structure of MSWI bottom ash micro powder concrete is uniformly distributed, displaying good fractal characteristics conducive to subsequent secondary hydration reactions. The inclusion of MSWI bottom ash micro powder increases concrete porosity, leading to a decrease in compressive strength. However, as the curing age increases, the value tends to approach that of ordinary concrete, suggesting that MSWI bottom ash micro powder exhibits potential hydraulicity, albeit with a slow hydration reaction. The observed pattern of MSWI bottom ash micro powder concrete aligns with that of ordinary concrete, wherein higher porosity corresponds to lower compressive strength. The addition of MSWI bottom ash micro powder increases concrete porosity, resulting in reduced compressive strength.

Recycling of municipal solid waste incineration bottom ash (MSWIBA) particles into natural fine sands for sustainable engineering cementitious composites

The manufacture of engineered cementitious composites (ECCs) consumes large amounts of natural fine aggregate. In this study, replacement of the natural fine aggregates in ECCs with municipal solid waste incineration bottom ash (MSWIBA) was found to reduce the consumption of natural river sand and the negative environmental impact of MSWIBA disposal. Previously, scholars have shown the potential of using MSWIBA particles as fine aggregates in concrete, but few scholars have evaluated ECCs with high percentages of MSWIBA powder in place of the natural fine aggregates. This study was conducted to design green ECCs by incorporating MSWIBA (BA–ECCs) to completely replace the natural silica sand with various fibers (PVA, PP and PE) and different fiber volume blends (0%, 0.5%, 1%, 1.5% and 2%) and to evaluate the BA–ECCs based on the fluidities, mechanical properties, microscopic morphologies, pore size distributions and heavy metal leaching capacities. The results showed that the addition of MSWIBA increased the porosities of the BA–ECCs. Compared with those of the control group, the maximum flexural strength of the BA–ECCs with 1.5% fiber doping were approximately 27.75% higher. There were relationships between the compressive strength and flexural strength and between the fiber volume content and strength. Moreover, microstructural observations revealed that the MSWIBA powder interacted strongly with both the matrix and the fibers, and the performance of the MSWIBA powder in the matrix was similar to that of a lightweight aggregate during internal curing. Additionally, fiber agglomeration (winding) at a 2% fiber content reduced the compressive and flexural strengths. The BA-ECCs showed lower heavy metal leaching contents than the MSWIBA, and the concentrations of various heavy metals were below the Chinese standards. Overall, this study could support research on the use of MSWIBA particles to prepare sustainable ECCs and recycle MSWIBA particles.

Use of municipal solid waste incineration (MSWI) bottom ash as a permeable subgrade material: An experimental and mechanism study

ABSTRACT As a traditional method of waste treatment, municipal solid waste incineration (MSWI) has become one of the main methods of urban waste treatment. However, as a byproduct of MSWI, a large amount of MSWI bottom ash is not reused in current practice. This study innovatively posits MSWI bottom ash as an eco-friendly adsorbent rather than a pollutant, exploring its potential application as a permeable subgrade material. The results reveal that MSWI bottom ash exhibits promising properties to serve as a permeable subgrade material to achieve the permeability and improve the sustainability for subgrade. Due to the arrangement of its particles, it shows excellent performance in shear strength and permeability, which are comparable to or surpass those of sandy soils. The average pore width of 14.200 nm allows heavy metal substances to be encapsulated within the matrix, significantly reducing their leachability, thereby aligning with environmental friendliness standards. Its adsorption capacity is about 6.60 mg/g, and the adsorption capacity per volume is 3.66 times and 2.04 times that of fly ash and clay, respectively. The mechanism analysis shows that the adsorption process is monolayer heterogeneous adsorption. This paper presents a novel perspective on reusing MSWI bottom ash and provides evidence supporting its effective utilization as a permeable subgrade material, offering substantial environmental benefits through enhanced adsorption ability. Implications: Municipal solid waste incineration (MSWI) is a common method for municipal solid waste treatment, while the MSWI bottom ash is often not reused. This paper explored the explores the feasibility of using MSWI bottom ash as a permeable road base material. The results show that the particle arrangement enables excellent shear strength and permeability, comparable to sandy soil. It meets safety requirements for the leaching of heavy metals and acts as an adsorbent for pollutants leaching from permeable pavements. Furthermore, the mechanisms underlying these behaviors of MSWI were confirmed by microstructural and mineralogical analyses. These indicate that MSWI bottom ash has great potential as a permeable road base material. This paper provides a clear understanding of the physical, mechanical and environmental properties of MSWI bottom ash, which can promote its reuse in practice.

CaO-based adsorbents derived from municipal solid waste incineration bottom ash for CO2 capture

The utilization of waste-derived adsorbents for CO2 capture presents a promising strategy for the reduction of adsorbent cost and waste volume. In this study, CaO-based adsorbent was prepared from Ca-rich municipal solid waste (MSW) incineration bottom ash (BA) as raw material. The effects of acid patterns, carbonization/calcination temperature, triblock copolymer (P123) and Mn loadings, as well as the steam contents in the flue gas on the cyclic CO2 capture capacity of the adsorbents were studied. The results showed that CaO-based adsorbents obtained by nitric- and acetic-acid extraction showed more stable adsorption capacity, due to more active CaO and less impurity content. When the Ca/Mn molar ratio was 100:1 and the concentration of P123 solution was 2 g/L, the prepared adsorbent showed the adsorption capacity of 0.321 g/g after 20 cycles, which was 175% of the unmodified CaO-based adsorbent (0.183 g/g). The addition of Mn and P123 increased the surface area and pore volume of the adsorbents, resulting in a dense distribution of pore size. Additionally, Mn could also inhibit the particle growth and mitigate sintering of the adsorbents. The electron transfer between Mn3+ and Mn4+ played a crucial role in generating labile oxygen vacancies, which improved the adsorption capacity of the adsorbents.

Preparation and characterization of polyvinyl alcohol (PVA)-glycerol composite films incorporating nanosilica from municipal solid waste incinerator bottom ash

This study investigates the fabrication of a composite film composed of polyvinyl alcohol (PVA) and glycerol, incorporating nanosilica derived from municipal solid waste incinerator bottom ash (BA). The nanosilica is blended with a PVA film-forming solution containing glycerol as a plasticizer. The composite films are characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Additionally, thermogravimetric analysis (TGA) is conducted to evaluate the thermal properties, while the mechanical properties are assessed in terms of tensile strength (TS) and elongation at break (EAB). The results indicate that the presence of silica nanoparticles reduces transparency and increases film thickness in the presence of glycerol. Notably, the film containing 1% silica demonstrates a significant enhancement in tensile strength, exhibiting a 50% increase compared to the film without silica. However, higher silica loadings lead to a deterioration in mechanical properties due to silica agglomeration within the polymer matrix. As expected, the presence of silica in the films slightly elevates the degradation temperature.

Environmental and mechanical analysis of low‐carbon concrete with vitrified MSW incineration bottom ash as cement replacement

AbstractThe building sector is responsible for about 37% of the global carbon dioxide emissions, 6% of which result from concrete (and particularly cement) production. Using recycled and supplementary cementitious materials and adopting a whole building life cycle approach can be seen as multi‐beneficial strategies for materials' design. In this framework, this study aims to formulate a green concrete, by replacing 10, 15 and 20% of cement with a secondary raw material constituted of vitrified bottom ash derived from municipal solid waste incineration. The basic physical and mechanical properties were measured up to 365 days, so to evaluate the effects of the cement replacement both on short and long‐term behavior. Life Cycle Assessment was used as a tool to evaluate the environmental performance of the developed green concrete. An Eco‐Mechanical Analysis was also performed to match the environmental impacts with the mechanical behavior, allowing to assess that the concrete produced by replacing 20% of cement with vitrified municipal solid waste incineration bottom ash (if classified as hazardous waste) is the one that leads to optimize the overall sustainability. The approach proposed in this work, which can be easily generalized, contributes to the definition of a route for the implementation of innovative green construction building materials by using waste.

Utilization of municipal solid waste incinerator bottom ash (MSWIBA) in concrete as partial replacement of fine aggregate

Enhancing sustainable economic development while maintaining environmental integrity is of paramount importance. In this context, the effective utilization of municipal solid waste incinerator bottom ash (MSWIBA) presents a significant opportunity. This study investigated an approach for harnessing the potential of MSWIBA by incorporating it as a partial replacement for fine aggregate in concrete mixtures. Twelve concrete samples were prepared with varying proportions of MSWIBA. The mechanical and microstructural properties of the samples were comprehensively investigated. Moreover, the environmental and economic advantages of these concrete formulations were assessed. The results revealed that the water absorption of the concrete samples without MSWIBA was higher than that of the concrete samples with MSWIBA, suggesting that the added MSWIBA could fill the internal pores of concretes. The water absorption rate curve could be divided into three stages, i.e., rapid decline, slow decline, and stable. The optimal replacement ratio of fine aggregate with MSWIBA was between 24.8% and 57.8%. Notably, when the replacement ratio surpassed 24.8%, MSWIBA positively influenced the development of compressive strength, but it still lower than that of composite Portland cement-based concrete (OPC). Furthermore, pore structure analysis indicated that the efficacy of pore refinement was achieved within a certain replacement threshold. However, the efficacy of pore structure refinement diminished beyond that threshold. The substitution of fine aggregate with MSWIBA aligns with the technical specifications and building material standards, thereby complying with the principles of effective utilization, sustainability, and environmental consideration pertinent to MSWIBA management.

Impacts of wet treatment on leaching toxicity of municipal solid waste incineration bottom ash

Impacts of wet treatment on leaching toxicity of municipal solid waste incineration bottom ash

A comprehensive assessment of green concrete incorporated with municipal solid waste incineration bottom: Experiments and life cycle assessment (LCA)

To reduce the high carbon emissions in the concrete field and facilitate the sustainable development of concrete, in this study, we repurposed high-volume municipal solid waste incineration bottom ash (MSWIBA) as a supplementary cementitious materials (SCMs) for the production of concrete at different percentages (0%, 10%, 20%, 30%, 40%, 50% and 60%). The influence of MSWIBA on the compressive strength, hydration, microstructure and heavy metal leaching behaviour of concrete was investigated. The results showed that a high volume of MSWIBA will reduce the compressive strength (from 56.81 MPa to 12.65 MPa) because aluminium produces hydrogen in an alkaline environment and excessive incorporation of MSWIBA leads to insufficient active substances. The content of ettringites and calcium silicate hydrate (C-S-H) initially increases (from 0.286 ％ to 0.405 ％ and from 0.635 ％ to 0.893 ％) and subsequently decreases (from 0.405 ％ to 0.275 ％ and from 0.893 ％ to 0.500 ％) as the proportion of MSWIBA in the mixture gradually increases due to the aluminium salt content reacting with the sulfate and pozzolanic reactivity of MSWIBA. In addition, compared with those in MSWIBA, the amounts of leachable hazardous ions (Cu, Pb, Cr, As and Hg) in concrete were effectively reduced by 87.1%, 83.3%, 70.0%, 90.3%, and 89.3%, respectively. Additionally, the measured heavy metal leaching met Chinese specification requirements. Life cycle assessment (LCA) was employed to evaluate environmental impacts (EIs), and it was found that using MSWIBA as a SCM can reduce the EI by 7.5 ％− 44.1 ％ (from 2.58E-11 to 1.56E-11) when the replacement cement ratio of MSWIBA is from 10 ％ to 60 ％. By normalizing the EI indices, it was found that the global warming potential (GWP) and eutrophication potential (EP) were the main contributors to the EI. Finally, a model was established to assess the comprehensive performance, including the environmental impact, compressive strength, porosity, apparent density, and ecology-strength efficiency, of the different MSWIBA formulations, and the comprehensive performance improved when the MSWIBA percentage was 30%.

Study on the Combined Effect of Municipal Solid Waste Incineration Bottom Ash and Waste Shingle in Hot Mix Asphalt.

This study investigated the positive effect of the combined use of recycled asphalt shingles (RASs) and municipal solid waste incineration (MSWI) bottom ash (B.A.) in asphalt concrete, which contributes to enhanced sustainability in pavement engineering. In addition, unlike traditional approaches that employ individual recycling material in hot mix asphalt (HMA), the combined use of the two waste materials maximizes the mechanical performance of the asphalt mixture. The addition of RAS (with 30-40% aged binder) as an additive generally enhances the strength/stiffness of the asphalt mixture. The high porosity/absorption of MSWI BA results in an additional amount of liquid asphalt binder in the mixture. As an admixture, RAS could supply the additional asphalt binder in the mixture when MSWI BA is used as an aggregate replacement. This research was conducted in two phases: (1) to examine the effect of MSWI BA alone and its optimal asphalt content (OAC), and (2) to assess the combined effect of B.A. and RAS in HMA. Multiple laboratory testing methods were employed for the mechanical performance investigation, including the Marshall stability test, rutting test, and indirect tensile test. The testing results show that the 20% B.A. replacement exhibits the best performance and that it requires an additional asphalt binder of 1.1%. For the combined use of MSWI BA and RAS, 5% RAS shows the best mechanical performance. All mixtures that contain the B.A. and RAS show greater strength than the control specimen (regular HMA).

Wet shaking table operating parameters optimization for maximizing metal recovery from incineration bottom ash fine fraction

Municipal solid waste incineration bottom ash has emerged as a secondary source of valuable metals, including aluminum and copper. Specifically, the fine fraction, with a particle size less than two millimeters, exhibits average grades of 2.5 g/kg for copper and 10.0 g/kg for elemental aluminum. Gravimetric concentration equipment, such as wet shaking tables, is widely used in the mining and recycling industries to concentrate materials based on density. However, the optimization of these devices typically relies on a trial-and-error approach. This paper presents a statistical model that optimizes the crucial working parameters of the wet shaking table for recovering elemental aluminum in a light product mineral matrix and copper in a high-density product. The statistical analysis highlights that upper values of shaking amplitude are beneficial for both the recovery and grade of copper and aluminum in the obtained products. Conversely, variations in other parameters, such as wash water or desk tilt, yield contrasting effects on grade and recovery. By precisely adjusting the working parameters of the device, the analyses demonstrate that copper enrichment of up to 45 times can be achieved in the product smaller than 500 µm and up to 15 times in the 500–2000 µm product, resulting in the recovery of approximately 65 % of the total copper.

Simplified framework for efficient utilization of municipal solid waste incinerator bottom ash as construction material via systematic classification and characterization

The incinerator bottom ash (IBA) constitutes approximately 80% of the municipal solid waste (MSW) incineration residues. To minimize the end-waste, one of the sustainable solutions is to utilize IBA. IBA is often utilized directly with or without simple pre-treatment after receiving from the incineration plant. However, the significant heterogeneity in the physicochemical composition of the IBA has hindered its widespread utilization. The given study proposes a simplified framework to improve the utilization efficiency of IBA via a systematic classification and characterization approach. The IBA was classified into ten classes (classified IBA) according to the four particle size ranges and three mineralogical categories. A comprehensive characterization of chemical/mineralogical compositions of classified IBA using state-of-the-art techniques was then conducted to understand the properties of each class, which aid in determining the appropriate applications for each category of classified IBA. The leaching behavior of the classified IBA was also studied to evaluate the environmental safety of the classified IBA classes and suggested avoiding categories with high concentrations of leachable toxic elements. The framework developed in this study for efficiently utilizing IBA is demonstrated for IBA collected from a local incineration plant.

Towards a circular economy: Recapturing battery, metal, and plastic from soil-size and gravel-size municipal solid waste incineration bottom ash using convolutional neural networks

Utilizing municipal solid waste incineration bottom ash (MIBA) to replace natural aggregate as building material substitutes is running under a circular economy worldwide. Applying pretreatments on MIBA to achieve manageable environmental impacts due to the complex composition of it becomes as a necessary route. We explored the convolutional neural network (CNN) techniques to identify quality scenarios of soil-size (<2 mm) and gravel-size (4–19 mm) MIBA, using 10,122 customized images divided into groups of 5060 normal/visible images and 5062 infrared images with different image resolutions. The CNN models achieved an interpretation accuracy ranging from 83.1% to 97.33% for scenarios of quality consideration under normal and infrared illumination. In addition, the visibility analysis revealed that well-trained CNNs models could detect the unsuitable remains/residues features of metals and batteries, in MIBA. The findings highlighted this model's considerable potential in the field of waste recycling and the recapturing of battery, metal, and plastic from soil-size and gravel-size MIBA.

Adhesion property of municipal solid waste incinerator bottom ash and limestone with asphalt based on surface energy theory

ABSTRACT The aim of this paper is to investigate the adhesion of municipal solid waste incinerator bottom ash (MSWIBA) and limestone to asphalt using the principles of surface energy theory. MSWIBA asphalt mixes are known for their satisfactory water stability, with adhesion being a crucial factor, as demonstrated in previous freeze-thaw splitting tests. Contact angles of ground MSWIBA and limestone were measured using a capillary rise test, eliminating the influence of material surface structure. Subsequently, adhesion work and spalling work were calculated to correlate with water-induced damage. The results showed that the sequence of adhesion work was fine MSWIBA > limestone > coarse MSWIBA, while the sequence of spalling work was coarse MSWIBA > limestone > fine MSWIBA. The adhesion of MSWIBA asphalt mixes was evaluated using the water boiling test image method to validate the findings of surface energy theory. In both asphalt tests, the spalling rate followed this sequence: coarse MSWIBA > limestone > fine MSWIBA. The Adhesion index ER ranked as follows: ER Fine MSWIBA > ER limestone > ER coarse MSWIBA. These results suggest that the water stability of MSWIBA asphalt mixes is influenced by the surface energy of the components. Consequently, indices derived from surface energy theory can be applied in formulating and predicting the properties of MSWIBA asphalt mixes.

From waste to resource: utilizing municipal solid waste incineration bottom ash and recycled rubber in pervious concrete pavement

From waste to resource: utilizing municipal solid waste incineration bottom ash and recycled rubber in pervious concrete pavement

Research on composite municipal solid waste incineration bottom ash and granulated blast furnace slag based geopolymers with sodium alginate for sealing coal seam gas drainage boreholes

This study has created geopolymer sealing materials from sodium alginate (SA), granulated blast furnace slag (GBFS), and municipal solid waste incineration bottom ash (MSWI-BA) to see how well they can seal coal seam gas drainage boreholes. In comparison to ordinary cement sealing material (CSM) and neat MSWI-BA based geopolymer, composite geopolymer sealing material (SIG) with 0.1 wt% SA has the advantages of appropriate setting time, improved fluidity, and increased compressive strength. Additionally, SIG demonstrated a slight expansion that aids in maintaining the durability of the seal. However, when compared to neat geopolymer, the addition of sodium alginate increased porosity and permeability slightly, but not to levels higher than CSM. Based on the microstructural characterization, a mechanism for the formation of SIG with coordination crosslinking structure in the network of C-A-S-H and N-A-S-H gels was proposed. The created composite geopolymer material, which is based on MSWI-BA and GBFS, therefore, has a lot of potential for use as sealing materials in coal seam gas drainage boreholes.

Development of Eco-Mortars with the Incorporation of Municipal Solid Wastes Incineration Ash.

The cement sector is the second largest contributor to anthropogenic CO2 emissions, and several efforts have been made to reduce its environmental impact. One alternative that has gained interest in recent years involves the use of municipal solid waste incineration (MSWI) bottom ash (BA) as clinker/cement replacement. This paper studies the application of MSWI BA in three different ways: (i) aggregate (0 to 100 v/v %), (ii) partial binder substitute (0 to 30 v/v %), and (iii) filler (5 v/v %). It stands out for its approach in characterizing seven distinct BA particle sizes and for the development and analysis of eco-cement mortars with only mechanically pre-treated BA. Hardened state properties showed that the use of BA as aggregate leads to deterioration and efflorescence formation on the surface of the mortars, making this application unfeasible. The replacement of 15 v/v % of OPC (Ordinary Portland Cement) by BA and the use of finer (<63 μm) BA as filler caused a decrease in the compressive strength of the mortar, from 15.8 to 9.3 and 11.0, respectively. However, these materials are suitable for use in walls where the minimum required mechanical resistance is 5 MPa. Furthermore, these mortars demonstrated resilience against freeze-thaw cycles and even exhibited increased compressive strength after 25 cycles. Thus, this work showed that MSWI BA can be used as an OPC substitute (up to 15 v/v %) and as a filler, promoting circular economy principles and reducing CO2 emissions related to the construction industry.

Reactivity and leaching potential of municipal solid waste incineration (MSWI) bottom ash as supplementary cementitious material and precursor for alkali-activated materials

This work evaluated the reactivity and leaching potential of municipal solid waste incineration (MSWI) bottom ash as supplementary cementitious material (SCM) and precursor for alkali-activated materials (AAM). The chemical composition of the amorphous phase in MSWI bottom ash was found to be in the same range as that of Class F coal fly ash. The reactivity of MSWI bottom ash as SCM and AAM precursor was tested to be much lower than that of blast furnace slag, but similar to that of Class F coal fly ash. The method of thermodynamic modeling was found useful in providing references for the mix design of MSWI bottom ash-based AAM. Grinding MSWI bottom ash into powder for the application of SCM and AAM precursor increased its leaching potential. Based on the findings of this study, recommendations were provided on how to use MSWI bottom ash to prepare blended cement pastes and AAM.

Qualitative and quantitative characterization of metallic aluminum in municipal solid waste incineration bottom ash

The reaction of alkaline solution and metallic aluminum present in municipal solid waste (MSW) incineration bottom ash (IBA) generates hydrogen gas. Thus, it is crucial to characterize the metallic aluminum in IBA for its safe utilization and proper disposal. However, the inherent inhomogeneity of IBA, random distribution of metallic aluminum in IBA grains, presence of aluminum in compound forms, and lack of reliable quantitative characterization techniques pose significant challenges to the holistic understanding of metallic aluminum in IBA. This research aims to address these questions systematically and present a comprehensive understanding of metallic aluminum in IBA. A classification strategy based on mineralogical and particle size basis is adopted to minimize the inhomogeneity of IBA. Furthermore, the spatial distribution of metallic aluminum in IBA is studied through SEM/EDS of the IBA grains cross-sections of different particle sizes and mineralogical classes. Subsequently, a modified in-house designed collecting gas over liquid setup was developed for an easy and reliable quantitative characterization. The metallic aluminum content was the highest for 0.3–1.18 mm and lowest for < 0.3 mm range, and within a given mineralogical class, the metallic aluminum content decreases with decrease in particle sizes. The microanalysis of cross-sections of IBA grains showed that the aluminum is present as aluminum alloy formed during incineration or in oxide form, majorly in fine fractions (< 0.3 mm). The current study seeks to provide a complete picture of metallic aluminum distribution in IBA.

Feasibility of preparing self-compacting mortar via municipal solid waste incineration bottom ash: an experimental study

Feasibility of preparing self-compacting mortar via municipal solid waste incineration bottom ash: an experimental study