Municipal Solid Waste Incineration Residues Research Articles

Viscoelastic Characteristics and Mechanical Performances of Asphalt Mastic and Mixtures with Fly Ash from Municipal Solid Waste Incineration Residues

Viscoelastic Characteristics and Mechanical Performances of Asphalt Mastic and Mixtures with Fly Ash from Municipal Solid Waste Incineration Residues

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.

Thermal Characteristics and Temperature Distribution of Asphalt Mixtures Containing Residues from Municipal Solid Waste Incineration

As a sustainable substitute for non-renewable mineral resources and solid waste landfilling, municipal solid waste incineration residues (MSWIRs) are useful in road pavements. This study investigates the thermal characteristics and temperature distribution of flexible pavements containing MSWIRs with hollow microsphere structures. First, the volumetric properties of asphalt mixtures containing MSWIR fillers were measured. The effects of MSWIRs on the mixture’s physical characteristics were investigated in terms of thermal conductivity, specific heat capacity, and thermal diffusivity. A three-dimensional finite element model incorporating surface thermal conditions was established and validated to analyze the internal temperature distribution and heat transfer behavior within the asphalt. Finally, the high-temperature conditions of summer were simulated in an indoor irradiation test to evaluate the risk of heat islands in urban areas. The results showed that the mixture containing MSWIRs exhibited a higher specific heat capacity (from 0.8385 to 0.9554 J/(kg·K)) and lower thermal conductivity (from 1.4356 to 1.1362 W/(m·K)) than the reference mixture with limestone filler. Therefore, it contributed to a lower heat flux distribution within the pavement. However, the increase in asphalt surface temperature caused by MSWIRs may exacerbate the urban heat island effect in the summer, which should be considered before using road materials containing MSWIRs.

The Idea of the Recovery of Municipal Solid Waste Incineration (MSWI) Residues in Kłodawa Salt Mine S.A.by Filling the Excavations with Self-Solidifying Mixtures

In view of the permanent increase of the municipal solid waste incineration (MSWI) residues amount, the numerous attempts to find a way of their recovery have been undertaken. In this paper the idea of the recovery of the MSWI residues in Klodawa salt mine is presented. The idea is to fill the waste in underground workings, close and/or backfill the underground excavations with self-solidifying mixture prepared on the basis of MSWI grained solid residues. Two techniques are proposed: 1) hydraulic backfill technique (HBT) where the mixture is prepared in the surface installation and pumped down into the underground workings through shaft and the pipelines and 2) dry waste technique (DWT), where dry grained waste is dropped into the mine by pneumatic pipeline transport, then supplied to the underground mixture-preparing- installation and pumped as a thin liquid or paste into the selected workings. The description of the technology is preceded by general characteristic of the hardening backfill in underground mines and by characteristic of MSWI residues, drafted on the basis of the literature review.

Rheological and Fatigue Characteristics of Asphalt Mastics and Mixtures Containing Municipal Solid Waste Incineration (MSWI) Residues

The large-scale implementation of municipal solid waste incineration (MSWI) has put great pressure on waste management and environmental protection. Road construction engineering has also been confronted with the challenges of the heavy consumption of non-renewable mineral resources. Therefore, we evaluated the feasibility of recycling and reusing MSWI residue as an alternative to limestone filler (LF) in transport infrastructure. We investigated the rheological characteristics and fatigue performance of asphalt mastics and mixtures containing MSWI residue. Firstly, a particle size analyzer and environmental scanning electron microscope were adopted to characterize the particle distribution and surface micromorphology of the investigated fillers, respectively. Then, tests for determining the steady shear viscosity and multiple-stress creep recovery were conducted to evaluate the high-temperature rheology of five asphalt mastics. Meanwhile, we used Burgers models with fitting parameters to describe the classic creep recovery measurements and viscoelastic responses. The wheel-tracking test revealed the rutting resistance, and the linear amplitude sweep (LAS) and time sweep tests were combined to investigate the fatigue performances of the five asphalt mastics. A dynamic creep test identified the fatigue life of the asphalt mixtures according to the flow number index. Finally, statistical analysis was conducted to identify the correlations between the rheological and fatigue properties of the mastics and mixtures (R2 over 0.87 and 0.78, respectively). Since the fatigue life predictions for the asphalt mastic decreased by over 42.9% according to the MSWI residue/LF volume ratio, the results of the correlations could improve pavement designs. The substitution of the mineral filler in asphalt mixtures with MSWI residue could be a sustainable strategy for the road construction sector.

Urban mining of municipal solid waste incineration (MSWI) residues with emphasis on bioleaching technologies: a critical review.

Metals are essential in our daily lives and have a finite supply, being simultaneously contaminants of concern. The current carbon emissions and environmental impact of mining are untenable. We need to reclaim metals sustainably from secondary resources, like waste. Biotechnology can be applied in metal recovery from waste streams like fly ashes and bottom ashes of municipal solid waste incineration (MSWI). They represent substantial substance flows, with roughly 46 million tons of MSWI ashes produced annually globally, equivalent in elemental richness to low-grade ores for metal recovery. Next-generation methods for resource recovery, as in particular bioleaching, give the opportunity to recover critical materials and metals, appropriately purified for noble applications, in waste treatment chains inspired by circular economy thinking. In this critical review, we can identify three main lines of discussion: (1) MSWI material characterization and related environmental issues; (2) currently available processes for recycling and metal recovery; and (3) microbially assisted processes for potential recycling and metal recovery. Research trends are chiefly oriented to the potential exploitation of bioprocesses in the industry. Biotechnology for resource recovery shows increasing effectiveness especially downstream the production chains, i.e., in the waste management sector. Therefore, this critical discussion will help assessing the industrial potential of biotechnology for urban mining of municipal, post-combustion waste.

Pile covering of waste disposal using technosols made of municipal solid waste incineration bottom ash and coal combustion residues: A column leaching experiment

Technosols are characterized by a substantial quantity of artifacts or industrial wastes in the upper 100 cm. They can be used as cover caps in mining rehabilitation, in which vegetation cover is subsequently established. However, prolific vegetation growth can be limited by the chemical and physical properties of technogenic substrates. As further studies need to be conducted to evaluate the suitability of municipal solid waste incineration bottom ash and coal combustion residues as cover caps, the pH, electrical conductivity, total porosity, and bulk density of these substrates were measured. Furthermore, the seepage pH and electrical conductivity of the covered and uncovered technosols after saturation were determined. The municipal solid waste incineration bottom ash, 4–10 mm in diameter, showed the highest bulk density (1.16 g cm-3) and lowest total porosity by saturation (24.7%). In contrast, the coal combustion residues registered the highest total porosity (57.2%). The coal combustion residues also revealed a higher pH of 12.5 and electrical conductivity values of 7.8 mS cm-1. Furthermore, no differences were observed between the treatments for pH seepage (8.2–8.3) and its electrical conductivity (14.3–16.0 mS cm-1) in the covered and uncovered columns, when using a technosol. This study provides information on the use of municipal solid waste incineration bottom ash and coal combustion residues as evapotranspiration covers during mining rehabilitation. The management of municipal solid waste residues is a global challenge and the use of this resource is valuable not only for the mining industry but potentially also in other fields, such as construction. The heavy metal content of the bottom ash from municipal solid waste incineration and coal combustion residues should be studied before implementing these waste residues on a large scale.

Assessing the Metal Recovery Value of Municipal Solid Waste Incineration Residues: Impact of Pretreatment on Fly Ash and Bottom Ash

Assessing the Metal Recovery Value of Municipal Solid Waste Incineration Residues: Impact of Pretreatment on Fly Ash and Bottom Ash

Form of the Occurrence of Aluminium in Municipal Solid Waste Incineration Residue—Even Hydrogen Is Lost

In the bottom ash (BA) of municipal solid waste incineration, the content of iron and aluminum is relatively high. The efficiency of eddy current extraction of non-ferrous metals (including aluminium) routinely used in incineration plants is limited. The determination of the form of occurrence of aluminium or aluminium-rich components in BA is important in terms of its recovery or utilisation. BA from a newly built incineration plant in Poland was analysed using chemical analysis, X-ray diffraction, optical microscopy, and scanning electron microscopy with chemical microanalysis. Samples of water-quenched BA were analysed. For comparison, a non-quenched sample (collected above a water tank) was analysed. The obtained results indicate that aluminium-rich components in BA are present in both the melt phase and quench phase. In the melt phase (glassy material), the content of aluminium is low (usually below 2 wt%). Aluminium-rich components present in glass, inherited after aluminium products are usually oxidised, and occur as platy or irregular forms. Aluminium components in the quench phase are significantly transformed with the common presence of Cl− and SO42− phases formed during reaction with the quench water. Secondary phases form simple or complex rims around metallic or slightly oxidised cores, of which the size is significantly reduced during transformations. The variety in the forms of aluminium occurrence in BA makes its recovery challenging and inefficient. The reduced content of metallic aluminium indicates that the potential for hydrogen generation of BA is low.

Thiourea leaching of gold from processed municipal solid waste incineration residues

Incineration is one of the key technologies in disposal of municipal waste, which produces municipal solid waste incineration (MSWI) residues with high valuable metal contents. The recycling strategy for the MSWI residues is typically focused on the recovery of scrap metals yielding processed municipal solid waste incineration residues (PIR) as the main byproduct. However, the PIR still contains valuable metals, particularly gold, which cannot be extracted by conventional methods. Here, we evaluated the feasibility of using the 0.5–2.0 mm grain size fraction of PIR containing 28.82 ± 1.62 mg/kg of gold as raw material for a two-stage extraction process. In the first stage the alkalic fine-grained PIR was acidified with a solution of 20% (v/v) of HCl-containing flue gas cleaning liquid that is obtained by the municipal waste incineration plant itself as a waste product. In the second stage we leached the acidified fine-grained PIR by thiourea with Fe3+ as an oxidant. Application of the thiourea-Fe3+ leaching system resulted in recovery of 16.4 ± 1.56 mg/kg of gold from the fine-grained PIR within 6 h of incubation. Due to high gold market prices, upscaling of the suggested technology can represent a suitable strategy for gold recovery from PIR and other MSWI residues.

Municipal solid waste incineration residues recycled for typical construction materials-a review.

Focusing on the great potential of municipal solid waste incineration (MSWI) residues in the construction sector, the applications of recycling MSWI residues in construction materials are discussed in this review. Incineration is a promising method for managing the great quantity of municipal solid waste (MSW). Careful handling of incineration residues including fly ash, air pollution control (APC) residues, and bottom ash is required for this approach. The yield of these residues is large, and they contain many toxic and harmful substances. On the other hand, these residues contain valuable components such as SiO2, CaO, Al2O3, MgO, which are important components of building materials. Therefore, MSWI residues present huge opportunities for potential recycling and reuse in the construction and building industry. This paper summarized and discussed the application of MSWI residues in four typical building materials including cast stone, glass-ceramic, cement, and concrete. Before utilization, three types of pretreatment methods can be used to reduce the toxicity of the residues and improve the performance of the products. In addition, the current issues and the prospects of this field, and the environmental impacts of this application were discussed. It was concluded that MSWI residues can be used to prepare building materials after proper treatment which can improve the mechanical and chemical properties of the residues. The recycling can gain significant economic and environmental benefits at the same time. However, further researches on treatment methods for fine particles are needed.

Impact of electrodialytic remediation of MSWI fly ash on hydration and mechanical properties of blends with Portland cement

Municipal solid waste incineration (MSWI) residues such as fly ash and air pollution control (APC) residues may serve as new supplementary cementitious materials (SCM). These SCMs may, however, require a pre-treatment to improve material properties. This study investigates the impact of electrodialytically remediated (EDR) MSWI residues to remove heavy metals and salts, on the phase development, setting, and compressive strength development of composite cements with 10 wt% cement replacement, compared to inert quartz or untreated (raw) MSWI residues. All treated MSWI residues showed reactivity in mortar, resulting in higher compressive strength than inert quartz, attributed to additional ettringite and monocarbonate formation. The results indicate that electrodialytical remediation improves the performance of MSWI fly ash in blends with Portland cement, while MSWI APC residues might be used without pre-treatment.

Performance of eco-concrete made from waste-derived eco-cement

Abstract In this study, an eco-cement was synthesized primarily from municipal solid waste incineration (MSWI) residues and appraised as a stand-alone binder in concrete. In addition to thorough laboratory testing, appraisal was extended to a pilot trial involving full-scale masonry unit production. The raw feed of the contrived eco-cement was supplemented by fractional additions of calcium hydroxide (6 wt %) and sintered at a clinkering temperature of 1100 °C. The resulting clinker (eco-cement) demonstrated latent hydraulicity when reacted with water and strong carbonation reactivity when reacted with carbon dioxide. Carbonation curing was found to both increase and accelerate strength-yield – achieving almost 1.5 times the ultimate 90-day hydraulic strength in just one day – without compromising additional latent strength gains from subsequent hydration. The binder performance was benched against control specimens prepared from ordinary Portland cement (OPC). The study’s final “eco-concrete” was activated by carbonation for early strength and further hydrated for latent strength. Eco-concrete demonstrated improved durability over conventional concrete according to surface resistivity, freeze-thaw, and drying-shrinkage evaluations. Moreover, leaching results for commonly regulated heavy metals and chlorine confirmed the environmental stability of eco-concrete according to the adopted standard testing protocol. Finally, the field pilot demonstrably validated eco-concrete’s suitability as a commercial product, where manufactured full-size concrete masonry units (CMUs) met all physical and performance requirements of CSA-A165 and ASTM-C90 standards. The synthesis of eco-cement, and its use as a carbon-sequestering alternative binder in eco-concrete, holds reasonable merit for consideration as an adaptable cleaner production to improve current-day MSW incineration practice.

Use of eco-admixture made from municipal solid waste incineration residues in concrete

With the phasing-out of coal power plants in many developed countries, a steep shortage in construction-grade fly ash – a widely used mineral admixture in concrete – seems inevitable. In this study, an eco-admixture prepared from a raw blend of municipal solid waste incineration (MSWI) residues was investigated as a possible cement replacement in concrete. The eco-admixture was synthesized at incineration temperature of 1100 °C from a carefully selected stoichiometric combination of three residues sourced from a local incinerator and minor additions of slaked lime. Paste and concrete specimens were prepared with 15% cement replacements and compared to commercial mineral admixture and ordinary Portland cement (OPC) control. In addition to normal hydration, carbonation was explored as an alternative curing scenario for accelerated early strength activation. The influences of cement substitution on mechanical properties, leaching performance, microstructure, and resistance to freeze-thaw damage were examined. The major reactive mineral components of eco-admixture were found to be belite and chloro-ellestadite. In hydration, paste and concrete specimens containing eco-admixture were comparable in performance to straight OPC control; however, they displayed much improved strength and resilience when activated by carbonation. Leaching tests affirmed the environmental stability and suitability of eco-admixture as a supplementary cementitious material (SCM) in concrete. For further validation, a pilot production was carried out at a commercial concrete plant to produce a cubic meter of standard 20 cm concrete masonry units (CMUs). The CMUs with eco-admixture displayed comparable strength to the OPC references and satisfied all physical performance required by load-bearing standards.

Geochemical and magnetic data on anthropogenic ashes from municipal solid waste incineration (MSWI).

This paper reports supplementary information to “Understanding room-temperature magnetic properties of anthropogenic ashes from municipal solid waste incineration to assess potential impacts and resources” [1]. The sample-set is composed of 47 samples of bottom (BA) and fly (FA) ashes from Municipal Solid Waste Incineration (MSWI), including eight magnetic extracts of selected BA and FA materials. The sampling relies on a simple random sampling strategy at four different MSWI sites in Northern Italy [2]. X-Ray Fluorescence (XRF) analysis on pressed powder pellets, microscopic observations on thin sections and stubs, and magnetic analysis were carried out.Various magnetic measurements are presented: the magnetic susceptibility measured at two different frequencies (0.47 and 4.7 kHz); the mass-specific susceptibility of ARM (χARM), expressed in m3/kg, calculated after mass-normalization and bias DC field correction; experiments for isothermal remanent magnetization (IRM) experimented were also conducted. The latter measurement allowed the calculation of additional parameters, such as the coercivity of remanence (B0cr) and the S-ratio [3]. The IRM acquired in a field of 1.0 T was regarded as the saturation IRM (SIRM). Mass-specific magnetic susceptibility (χ) was calculated by dividing the volume susceptibility by the sample mass. Finally, hysteresis loops and backfield curves at room temperature were measured on selected samples and are available. Data can be reused as groundwork information in future studies on MSWI residues. It would be essential to produce new data on geochemical and magnetic characteristics of MSWI residues to assure good coverage of data for enhanced sustainability of these heterogeneous streams of anthropogenic materials. This combination of methods will contribute to paving the way for quick and reliable resource assessment as well as to promote environmental sustainability.

Enhanced electrodialytic bioleaching of fly ashes of municipal solid waste incineration for metal recovery

Metal recovery from wastes is essential for a circular economy and minimising present-day society environmental footprint. In this study, we combined electrodialysis with bioleaching of fly ashes for enhanced metal recovery from municipal solid waste incineration residues. Results showed that the use of low-level direct current with acidophilic bacteria enhanced metal recovery in the catholyte when compared to the abiotic experiment supplied with direct current and the bioleaching experiment without direct current. The use of electrodialysis with bioleaching showed increased performance on the removal and recovery of metals in the catholyte such as Al, Cd, Co, Li, Pb, and Zn. While Co and Ni were selectively mobilised by bioleaching, Cu, Cr, Cd and Li showed highly elevated concentrations by combining both techniques. These results are proof of concept of combined methods will allow optimising the process, especially varying the liquid to solid ratio, mixing, duration of the experiments, and pH control in the anolyte.

Developing material recovery projects: Lessons learned from processing municipal solid waste incineration residues

This research explores the material recovery from bottom-ash, which is a residue from municipal solid waste incineration. The investigations aimed to characterize, evaluate, categorize and classify the development status of the recovery projects in the Canton of Zürich, including two technology pathways, i.e. dry and wet bottom-ash recovery. The temporal scale commenced with the exploration phase in 2003 and concluded with two technological pathways, both operating commercial projects in 2017. A retrospective view allowed the identification of enablers and barriers that affected the development status of the recovery projects. Further the recovery perspective allowed the results to be communicated to the United Nations Framework Classification for Resources (UNFC). The investigation showed two main trends. Firstly, the development status of the recovery projects from exploration to commercial project phase was mainly driven by the knowledge increase regarding sampling and metal characterization in bottom-ash, the readiness and effectiveness of the recovery technologies and the changes of the legal and financial environment. Secondly, the amount of recovered material (dry matter content) increased from about 6900 tons in 2003 to 16,500 tons in 2017, which is congruent with an increase in the recovery rate from 5 to 14 percent per weight. In particular, the amount of elements recoverable with an economic and environmental benefit, such as copper, gold and silver, increased. Correspondingly, the residual particular metal content in the disposable bottom-ash (fraction 2–16 mm) decreased to < 1 percent per weight dry matter and therefore reduced the risk for environmental at the sanitary landfills. The findings provide ‘lessons learned’ for companies, authorities and investors who intend to develop material recovery projects. Even though the recovery potentials depend on site-specific conditions, the UNFC allows comparing individual recovery projects under different boundary conditions.

MSWI Bottom Ash Application to Resist Sulfate Attack on Concrete

This research provides a strategy for partially replacing cement with municipal solid waste incineration (MSWI) bottom ash (BA) to improve the performance of concrete against sulphate attack. Mortar strength tests were performed firstly to evaluate the hydration activity of the ground BA. Concrete specimens were cured in standard conditions and immersed in a solution that contained 10% sodium sulfate. Then, the compressive strength of these specimens was measured to investigate the mechanical properties and durability of the concrete. Next, the capillary porosity of the concrete was determined from the volume fractions of water lost in specimens. Finally, the transport of the sulphate solution in concrete was analyzed using capillary rise, crystallization rate, and solution absorption tests. The results indicated that BA had a certain hydration activity. The equivalent replacement of cement by BA decreased the compressive strength of the specimens but increased the durability of the concrete. There was an excellent correlation between capillary rise height, sulfate solution absorption amount, crystallization rate, and coarse capillary porosity. The addition of BA can decrease the coarse capillary porosity and further slow the capillary transport and crystallization of sulfate solution in concrete. Overall, the replacement of cement with BA can improve the durability of concrete and actualize the utilization of MSWI residues as a resource.

Characterization of Leachates from Landfills Containing MSW-I Residues

The objective of this study was to characterize the leachate collected from landfills containing municipal solid waste incineration (MSW-I) ashes in the range of 20%–100% by weight. Results suggested that the conductivity and concentrations of major cations (Na+,K+,Ca2+) and anions (Cl− and Br−) increased with ash content, while alkalinity decreased with ash content. MSW-I ash contents had little effect on pH, TOC, NH4+, trace metals, and SO42−. Comparing the metal composition in the MSW-I ashes and associated ash monofill leachate, the leaching of metals, including Mg, Fe, Cu, Ni, and Al, were not as significant as expected. As, Cd, Pb, and Zn in ash monofill leachate were even below the quantification limit. The effect of MSW-I ash on landfill systems is further discussed. Leachate containing the MSW-I ash might increase the risk of leachate collection system (LCS) clogging. The risk of mineral precipitation in the LCS increased with the ash content mainly due to the increasing concentration of Ca. High ionic strength as well as the high anion ratio of the leachates might increase the hydraulic conductivity of geosynthetic clay liners (GCLs).

An algorithm for the use of MSWI bottom ash as a building material in road pavement structural layers

Municipal solid waste incinerator (MSWI) bottom ash (constituting approximately 80–90%) and fly ash are by-products of the incineration of solid waste. In general, MSWI residues are primarily discarded into landfills. To address the continuous growth of landfills and to implement zero waste and circular economy policies, researchers are focusing on more efficient ways of using MSWI bottom ash. To that end, the best practices show that MSWI bottom ash is suitable for civil engineering applications, especially roads. Therefore, the subject of this research was the performance of subgrade and different unbound and bound pavement structural layers containing bottom ash. An algorithm was also introduced to facilitate the use of MSWI bottom ash as a building material. Soil and mineral aggregate mixtures with different percentages (0–100%) of bottom ash were designed and analysed, and more than 10 testing subjects containing a high amount of MSWI bottom ash were tested in the laboratory. The research revealed the suitability of the 0/2 fraction of bottom ash to improve soil and to enhance the performance of asphalt concrete mixture AC 16 PD in which the 0/4 fraction of sand is replaced with the 0/2 fraction of bottom ash. Furthermore, the suitability of mixtures composed of mineral aggregates and MSWI bottom ash or only of MSWI bottom ash (100%) to construct sub-base and base courses was confirmed.