Search Results (55)

Municipal solid waste (MSW) incineration power generation has become the dominant waste treatment technology in China. However, acid flue gas dominated by HCl and SO₂ induces severe boiler corrosion, a surge in hazardous fly ash, and uncontrolled operational costs, significantly hindering the industry’s low-carbon transition. While conventional dry, semi-dry, and wet deacidification processes meet emission standards, they face an irreconcilable trilemma, failing to concurrently optimize removal efficiency, economic viability, and solid waste reduction. This review clarifies that high-temperature in-furnace deacidification represents a future development direction yet identifies two critical limitations: above 700 °C, external mass transfer remains the rate-controlling step, and the combined effects of CaSO₃ decomposition and sorbent sintering lead to inefficient desulfurization. Meanwhile, in the 130–400 °C range, HCl preferentially occupies active sites, inhibiting SO₂ adsorption. To address these challenges, this study proposes an innovative staged temperature–gradient synergistic deacidification pathway driven by catalytic oxidation. This strategy utilizes transition metals at high temperatures to oxidize SO₂ into SO₃, which is subsequently converted into thermally stable CaSO₄, while decoupling SO₂ pre-removal from the targeted capture of HCl in their respective optimal windows. Finally, four executable development directions are systematically proposed: industrial waste-based bifunctional sorbents, multi-field coupled gas–solid mass transfer intensification, staged deacidification processes, and full-process AI closed-loop control. These findings provide systematic theoretical support and actionable technical references for upgrading MSWI technology under China’s “Dual Carbon” and “Waste-Free City” initiatives. Full article

This study (Part B) examines the potential utilization of municipal solid waste (MSW) ash, produced in a semi-industrial incinerator in Israel, as a partial substitute for cement and natural sand in industrial concrete mixtures. The ash was produced at the temperature range 600–850 °C, and the ash was characterized using XRD and SEM to determine its mineralogical composition and morphology. The results indicate that ash composition is dominated by calcium-rich phases, with hatrurite (Ca₃SiO₅) representing approximately 51–66 wt.% of the identified crystalline phases, along with calcite, MgO, and silica phases. The ash consists of irregular, porous particles with a broad distribution. Concrete performance was evaluated in both fresh and hardened states. In terms of fresh concrete properties, it is observed that concrete containing ash showed improved workability, better workability retention, and better concrete density compared to concrete without ash. In terms of hardened concrete properties, the use of MSW ash as a partial sand replacement preserved the mechanical performance of the concrete, with compressive strength remaining within approximately 2% of the reference mixture. These findings suggest that semi-industrially produced MSW ash is more suitable as a fine aggregate replacement than as a supplementary cementitious material and represents a promising route for reducing landfill disposal and promoting circular economy practices in the construction industry. Full article

The co-gasification of biomass and municipal solid waste (MSW) has high potential for sustainable energy generation and waste-to-energy applications. Calliandra calothyrsus (CC) and MSW pellets have complementary thermochemical properties, although there are few experimental studies on their co-gasification in downdraft reactors. This study analyzed the effect of the feedstock composition on the temperature distribution inside the reactor, the syngas composition, and the quality of syngas energy in a 1–2.5 kg/h downdraft gasifier during co-gasification. Six feedstock blend compositions were experimentally evaluated: they were 100 CC, 70 CC–30 MSW, 60 CC–40 MSW, 40 CC–60 MSW, 30 CC–70 MSW, and 100 MSW. The criteria considered for measuring include reactor temperature distribution, syngas composition (CO, H₂, CO₂, and C_nH_m), and lower heating value (LHV). The results indicated that the 70 CC–30 MSW blend had the best syngas performance with a higher oxidation-zone temperature, greater CO concentration, reasonably steady H₂ generation, lower C_nH_m concentration, and the highest syngas LHV compared to other feedstock compositions. In the gasification process, the increase in the proportion of CC was beneficial to char reactivity, oxidation–reduction reaction, and tar cracking. The increase in MSW fractions decreased syngas quality due to the increase in ash and moisture content. The results show that co-gasification of Calliandra calothyrsus and bio-dried MSW pellets can increase syngas quality and provide practical insight into the optimization of biomass–MSW blending for downdraft gasification systems. Full article

Municipal solid waste (MSW) management faces increasing pressure due to rapid urbanization and the need for low-emission energy systems. This study investigates the thermogravimetric gasification behavior of Chinese MSW under CO₂, mixed air-CO₂, and SrMnO₃ (SMO) oxygen-carrier atmospheres to identify pathways for producing clean and higher-quality syngas. Using TGA-QMS, the gasification stages were monitored qualitatively and quantitatively over the temperature range of 750–1000 °C, while complementary FTIR, XRD, SEM-EDS, and ICP-OES analyses were employed to characterize the fresh waste and ash samples. Results show that CO₂ gasification is strongly dependent on temperature and concentration, producing CO via Boudouard reaction, resulting in a gas composition of 73% CO and 27% CO₂. An air-CO₂ mixture as a gasification agent shifted conversion toward combustion, producing high CO during oxidation but suppressing gasification, yielding syngas dominated by 90% CO and 10% CO₂. Introducing SMO significantly altered the reaction pathway via lattice-oxygen transfer: 7–56.75 mg SMO produced up to 97% CO and 3% CO₂, without external oxidants, demonstrating superior per-unit oxidizing capacity compared to CO₂. A mild synergistic effect was observed in the mixed CO₂-SMO investigation, where CO formation exceeded that obtained with CO₂ alone but remained lower than that in SMO-only gasification. In general, SMO-enabled oxygen donation provides a promising low-dilution, high-selectivity route for MSW gasification within thermogravimetric regimes. Full article

Fly ash (FA) captures most mercury (Hg) in the waste stream during municipal solid waste incineration (MSWI), and the content and speciation of Hg in MSWI fly ash (MSWI-FA) have a significant impact on the ecological environment. In this study, 245 fly ash samples were collected from 18 MSWI facilities in Guizhou Province, a fragile karst area with a high Hg background in Southwest China. The results indicate that total Hg ranged from 0.52 to 444 mg/kg among samples, while the geometric means varied from 0.85 to 223.33 mg/kg for different incinerators, with a weighted geometric mean of 22.14 mg/kg, more than double the national average. Substantial temporal variability in Hg content suggested intermittent inputs of Hg-rich waste into the MSW stream. While positive correlations (p < 0.05) were observed between Hg and chlorine, potassium, and cadmium, the moderate to low R² values indicate that Hg enrichment is a complex multi-factor system influenced by heterogeneous waste compositions and transient thermochemical conditions. Speciation analysis revealed that most of the Hg exists in its elemental form (F4), constituting over 80% of the total Hg. However, the water-soluble fraction (F1) and the ion-exchangeable fraction (F2) each reached up to 26–29% in some samples, indicating substantial environmental mobility. These findings demonstrate that MSWI-FA in Guizhou contains elevated Hg levels, posing considerable ecological and environmental risks. Enhancing the classification and management of Hg-containing waste in MSW is critical to mitigating the environmental risks of fly ash, particularly in karst ecological areas. Full article

Rising global municipal solid waste (MSW) generation poses severe environmental and resource challenges, necessitating sustainable management strategies beyond landfilling. This review critically synthesizes thermochemical waste-to-energy (WtE) technologies, including incineration, pyrolysis, gasification, and hydrothermal carbonization, as viable pathways for converting heterogeneous MSW into energy (electricity, heat, syngas, bio-oil) and valuable materials (biochar, ash for construction). Drawing on recent literature, it highlights their superior greenhouse gas reductions, energy recovery efficiencies, and residue valorization potential compared to traditional disposal, while addressing persistent limitations such as feedstock variability, tar formation, high capital costs, and stringent emission controls. Advanced variants and integration with circular economy principles enhance feasibility, particularly in diverse regional contexts. Despite technical and economic barriers, thermochemical WtE offers a transformative approach to resource-efficient waste management, supporting zero-waste goals and renewable energy transitions when combined with optimized pre-treatment, policy incentives, and ongoing innovation in process efficiency and pollutant mitigation. Full article

This study investigated the potential use of ash derived from Municipal Solid Waste (MSW), typically destined for landfill in Israel, as a partial replacement for cement and aggregates in concrete mixtures, aligning with circular economy and sustainable construction objectives. MSW samples (post-metal and large plastic remains removal), supplied by the Dudaim Reclamation Center in Israel, were incinerated under controlled conditions in an upgraded laboratory furnace to produce ash. The ash content in the Israeli MSW was 18% ash. The ash consisted mainly of calcium-based minerals, including anhydrite (CaSO₄), alite (3CaO·SiO₂), and calcite (CaCO₃), with minor quartz content, indicating potential pozzolanic behavior. The characterization results showed that appreciable amounts of ash produced from MSW incineration in Israel can be used as a partial replacement for cement and fine aggregates when properly treated. This study successfully established a laboratory-scale incineration process for Israeli MSW. The resulting ash was characterized, confirming its potential as a raw material for concrete applications, thereby paving the way for future studies on its performance as a partial substitute for cement and fine aggregates in concrete blends. Full article

Municipal solid waste incineration (MSWI) fly ash, classified as hazardous waste (HW18) due to the presence of heavy metals and dioxins, necessitates both harmless treatment and resource utilization. In this study, a Na-P1 zeolite adsorbent was synthesised from MSW incineration fly ash using its intrinsic Si and Al sources, supplemented by silica sol and sodium aluminate solution. The synthesised zeolite was employed for the adsorption removal of tetracycline hydrochloride (TCH) from wastewater. Under the optimised conditions (initial TCH concentration of 10 mg·L⁻¹, adsorbent dosage of 0.4 g·L⁻¹, pH 5.0, temperature 45 °C, and contact time 60 min), a maximum adsorption capacity of 14.8 mg·g⁻¹ and a removal efficiency of 59.1% were achieved. Kinetic analysis revealed that the adsorption process followed the pseudo-first-order model (R² = 0.975). The Langmuir isotherm provided a better fit than the Freundlich model (R² = 0.988), indicating monolayer adsorption on homogeneous sites. Thermodynamic parameters (ΔG < 0, ΔH > 0) confirmed that the adsorption was spontaneous and endothermic, with higher temperatures favoring enhanced TCH adsorption. This work demonstrates the feasibility of converting hazardous MSW incineration fly ash into a value-added Na-P1 zeolite adsorbent with excellent performance for antibiotic wastewater treatment, thereby offering a sustainable strategy for fly ash resource recovery and environmental remediation. Full article

Waste management poses escalating threats to environmental sustainability, particularly with municipal solid waste (MSW) growth. Incineration, a widely adopted method for reducing waste volume, produces millions of tons of municipal solid waste incineration fly ash (MSWIFA) each year. Despite its high toxicity and classification as a hazardous solid waste, its ultrafine particle size and pozzolanic activity offer potential for its use in construction materials. In this study, MSWIFA was used to replace 6%, 12%, 18% and 24% of cementitious materials, and the effect of MSWIFA substitution rate on the workability, mechanical properties, microstructure, and durability of UHPC was studied. Furthermore, the study assessed the solidification capacity of the UHPC for heavy metal ions and quantitatively analyzed its eco-economic benefits. The results show that, under standard curing conditions, substituting 12% of cementitious materials with MSWIFA significantly modified UHPC hydration, shortened setting time, reduced fluidity, and increased wet packing density. The 28-day compressive strength reached 134.63 MPa, comparable to the control group. Concurrently, fluidity, durability, and heavy metal leaching all met the required standards, with energy consumption reduced by 14.86%, carbon emissions lowered by 12.76%, and economic costs decreased by 6.41%. This study provides a feasible solution for recycling MSWIFA into non-hazardous concrete, facilitating sustainable hazardous waste management and mitigating heavy metal-related environmental pollution. Full article

Municipal solid waste (MSW) disposal is one of the areas of sustainability development of modern countries including the Republic of Kazakhstan. Annually, more than 4 million tons of MSW are generated, and this amount continues to grow. Additionally, approximately 120 million tons of waste have already accumulated in landfills across the country. It is essential to select an MSW disposal technology that is environmentally friendly, minimizes the generation of more hazardous waste, and maximizes energy efficiency. Ideally, the technology should not only reduce energy consumption but also generate energy and valuable by-products that have market demand. The aim of this study is to conduct experimental research to evaluate the efficiency and environmental impact of incinerating both unsorted and sorted municipal solid waste. As a result of the experiment, the volumes of flue gases and the concentrations of harmful substances produced by the combustion of both unsorted and sorted waste were determined. Additionally, an analysis of the slag and ash generated from the combustion of sorted MSW was conducted. The obtained results enable the development of a waste-free technological scheme for a plant designed for the complete utilization of municipal solid waste. Full article

As landfill mining becomes more widely applied, growing attention is being paid to the waste-to-energy conversion of landfill waste. Co-disposal of landfill waste with municipal solid waste represents one of the primary strategies for achieving energy recovery of landfill waste. In this paper, the emission characteristics of pollutants were systematically analyzed during the co-disposal of landfill waste and municipal solid waste in a full-scale municipal solid waste incineration. The study investigated the formation patterns of toxic PCDD/Fs and gaseous pollutants under different co-disposal ratios of landfill waste (0%, 15%, 25%, 35%, and 45%). In total, 136 PCDD/Fs were analyzed to investigate the influence of co-disposal ratios on PCDD/F formation in both flue gas and fly ash. The influence of varying co-disposal ratios on the phase and elemental composition of fly ash was also investigated. Co-disposal led to a significant reduction in the toxic PCDD/F concentration at the boiler outlet, mainly attributed to the higher sulfur content of LW compared to MSW. With increasing co-disposal ratios, the annual emission amounts of toxic PCDD/Fs in fly ash significantly increased. The ∑PCDD/∑PCDF ratio in both flue gas of boiler outlet and fly ash also increased, indicating an enhancement of the precursor formation pathway, while the de novo synthesis pathway was relatively suppressed. The fly ash exhibited a high proportion of highly chlorinated dioxins (degree of chlorination: 7.19–7.23), likely due to their low saturated vapor pressure. According to the Hagenmaier congener distribution, high co-disposal ratios (25–45%) suppressed the chlorination of DD/DF in fly ash but promoted the formation of gas-phase PCDFs. Different co-disposal ratios significantly influenced both the emission concentrations and removal efficiencies of air pollutants, including NOx, SO₂, and HCl. Although co-disposal did not alter the crystalline phase composition of fly ash, it led to an increased content of heavy metals such as Cu, Hg, and Pb. Full article

The modern world has brought extensive socioeconomic and ecological changes. Urbanization in developing nations has significantly increased municipal solid waste, necessitating in-depth understanding of waste composition particularly in developing nations for sustainable management practices. This study aimed to classify and characterize waste while evaluating potential waste management methods. Mixed methods were used to examine landfilled waste from Soshanguve and Hatherley sites in Tshwane Metropolitan, South Africa, using techniques such as Fourier transform infrared spectroscopy, X-ray fluorescence, proximate, and ultimate analysis. Seasonal variations in waste components were analysed over two seasons. The study identified that both sites are predominantly composed of organic waste, accounting for over 42 wt.%, with moisture content of ~50 wt.%, and minimal recyclables (<5 wt.%). Seasonal variations in MSW were significant for glass (<4% increase), organic waste (<5% increase), while plastic decreased by ~7% during spring. The biodegradable waste showed high carbon (>50%) and oxygen (>40%) levels, low ash content (<18%), and calorific values of 15–19 MJ/kg. Biodegradables mainly contained oxides of calcium, silicon, iron (III), and potassium with chemical composition indicating functional groups that emphasize composting and energy recovery benefits. The research provides insights into sustainable waste management, revealing waste composition at Tshwane landfills, aiding informed decision-making for resource usage and environmental conservation. Full article

Municipal solid waste (MSW) and refuse-derived fuel (RDF) incineration generate over 20 million tons of residues annually in the EU. These include bottom ash (IBA), fly ash (FA), and air pollution control residues (APCr), which pose significant environmental challenges due to their leaching potential and hazardous properties. While these residues contain valuable metals and reactive mineral phases suitable for carbonation or alkaline activation, chemical, techno-economic, and policy barriers have hindered the implementation of sustainable, full-scale management solutions. Accelerated carbonation technology (ACT) offers a promising approach to simultaneously sequester CO₂ and enhance residue stability. This review provides a comprehensive assessment of waste incineration residue carbonation, covering 227 documents ranging from laboratory studies to field applications. The analysis examines reactor designs and process layouts, with a detailed classification based on material characteristics, operating conditions, investigated parameters, and the resulting pollutant stabilization, CO₂ uptake, or product performance. In conclusion, carbonation-based approaches must be seamlessly integrated into broader waste management strategies, including metal recovery and material repurposing. Carbonation should be recognized not only as a CO₂ sequestration process, but also as a binding and stabilization strategy. The most critical barrier remains chemical: the persistent leaching of sulfates, chromium(VI), and antimony(V). We highlight what we refer to as the antimony problem, as this element can become mobilized by up to three orders of magnitude in leachate concentrations. The most pressing research gap hindering industrial deployment is the need to design stabilization approaches specifically tailored to critical anionic species, particularly Sb(V), Cr(VI), and SO₄²⁻. Full article

This study aims to obtain findings on the internal water behavior, the presence of water channels, and the degree of washout due to rainfall infiltration in Japanese municipal solid waste (MSW) final disposal sites. Electrical resistivity tomography (ERT) monitoring and undistributed waste sampling for X-ray computed tomography (X-ray CT) analysis were conducted in the field. The study sites were targeted at Site A, which is mainly composed of non-combustible residues, and Site B, which is mainly composed of incineration ash. The time-dependent resistivity distributions obtained from real-time ERT monitoring were effective for us to understand the water content distribution after water infiltration during water injection tests. As a result, the global flow behavior and the local water channel flow were determined. In addition, X-ray CT analysis of the undisturbed waste samples obtained from the sites clarified the different pore structures, indicating the possibility of more advanced washing out at Site A than at Site B. Furthermore, the soil cover layer and gas extraction wells had a significant effect on the resistivity structure with respect to water flow behavior. Since soil cover layer and gas extraction wells are significant factors affecting waste stabilization by washout, it is suggested that these factors should be considered in the design and maintenance of landfills. Full article

Renewable energy sources are presented as a key solution to today’s energy needs, but they also generate waste that can have a negative impact on the environment. In particular, fly ash from the incineration of municipal solid waste (MSW), classified as hazardous by European regulations, is often deposited in landfills due to its lack of usefulness. This research proposes its valorisation in geopolymers, combining it with mining to create a sustainable material with a high industrial waste content. Firstly, all the wastes involved were characterised, which allowed for the development of a high-quality geopolymer from mining residue activated with 5% NaOH. This material was enriched with up to 50% fly ash (in increasing percentages) with the aim of making it inert, retaining it in the geopolymer matrix, and observing its effect on the final material. The physical and mechanical properties of the geopolymers obtained were evaluated, demonstrating that they do not produce contaminating leachates. The results indicate the feasibility of developing a geopolymer with up to 20% fly ash, obtaining a building material comparable to traditional ceramics, suitable for commercialisation, with a lower environmental impact and in line with the principles of the circular economy. Full article