Search Results (226)

The dual environmental challenges of karst areas lie in organic solid waste’s (OSW) massive generation scale and diffuse dispersion, which accelerate bedrock exposure and soil contamination, while simultaneously representing an underutilized resource for soil amendments through optimized composting. Bio-enhanced composting of multi-source OSW yields compounds with dual redox/adsorption capabilities, effectively improving soil quality and restoring ecological balance. The recycling and circular utilization of OSW resources become particularly critical in karst regions with vulnerable soil ecosystems, where sustainable resource management is urgently needed to maintain ecological balance. This review elucidates the ecological impacts of multi-source OSW compost applications on soil environments in ecologically fragile karst regions, specifically elucidating the mechanisms of heavy metals (HMs) migration–transformation and organic contaminant degradation (with emphasis on emerging pollutants), and the functional role of microbial carbon pumps in these processes. Furthermore, establishing a sustainable “multi-source OSW−compost−organic matter (adsorption and redox sites)−microorganisms−pollution remediation” cycle creates a green, low-carbon microenvironment for long-term soil remediation. Finally, this study evaluates the application prospects of the refined composting technology utilizing multi-objective regulation for OSW resource recycling and utilization in karst areas. This review provides critical insights for optimizing soil remediation strategies in karst ecosystems through organic waste valorization. Full article

In this study, to solidify the silt in an expressway, a stabilizing agent composed of industrial wastes, such as ordinary Portland cement (OPC), calcium based alkaline activator (CAA), silicate solid waste material (SISWM) and sulfate solid waste material (SUSWM) was developed. Orthogonal experiments and comparative experiments were carried out to analyze the strength and water stability of the stabilized silt, and get the optimal proportion of each component in the stabilizing agent. A series of laboratory tests, including unconfined compressive strength (UCS), water stability (WS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses, were conducted on solidified silt samples treated with the stabilizing agent at optimal mixing ratios of OPC, CAA, SISWM, and SUSWM to elucidate the evolution of mineral composition and microstructure. Full article

The accelerated industrialization in China has precipitated a dramatic surge in solid waste generation, causing severe land resource depletion and posing substantial environmental contamination risks. Simultaneously, the cement industry has become characterized by the intensive consumption of natural resources and high carbon emissions. This review aims to investigate the current technological advances in utilizing industrial solid waste for cement production, with a focus on promoting resource recycling, phase transformations during hydration, and environmental management. The feasibility of incorporating coal-based solid waste, metallurgical slags, tailings, industrial byproduct gypsum, and municipal solid waste incineration into active mixed material for cement is discussed. This waste is utilized by replacing conventional raw materials or serving as active mixed material due to their content of oxygenated salt minerals and oxide minerals. The results indicate that the formation of hydration products can be increased, the mechanical strength of cement can be improved, and a notable reduction in CO₂ emissions can be achieved through the appropriate selection and proportioning of mineral components in industrial solid waste. Further research is recommended to explore the synergistic effects of multi-waste combinations and to develop economically efficient pretreatment methods, with an emphasis on balancing the strength, durability, and environmental performance of cement. This study provides practical insights into the environmentally friendly and efficient recycling of industrial solid waste and supports the realization of carbon peak and carbon neutrality goals. Full article

To address the practical limitations of conventional alkaline activators (e.g., handling hazards, cost) and promote the resource utilization of industrial solid wastes, this study developed a novel all-solid-waste activator system comprising soda residue (SR) and carbide slag (CS). The synergistic effects of SR-CS activators on the hydration behavior of blast furnace slag (GGBS)–fly ash (FA) cementitious composites were systematically investigated. Mechanical performance, phase evolution, and microstructural development were analyzed through compressive strength tests, XRD, FTIR, TG-DTG, and SEM-EDS. Results demonstrate that in the SR-CS activator system, which combines with desulfuriation gypsum as sulfate activator, increasing CS content elevates the normal consistency water demand due to the high-polarity, low-solubility Ca(OH)₂ in CS. The SR-CS activator accelerates the early hydration process of cementitious materials, shortening the paste setting time while achieving compressive strengths of 17 MPa at 7 days and 32.4 MPa at 28 days, respectively. Higher fly ash content reduced strength owing to increased unreacted particles and prolonged setting. Conversely, desulfurization gypsum exhibited a sulfate activation effect, with compressive strength peaking at 34.2 MPa with 4 wt% gypsum. Chloride immobilization by C-S-H gel was confirmed, effectively mitigating environmental risks associated with SR. This work establishes a sustainable pathway for developing low-carbon cementitious materials using multi-source solid wastes. Full article

While traditional disposal of solid waste from the global wine industry causes significant environmental burden and hazards, a range of value-added by-products can be produced from the grape marc. This review focuses therefore on crucial sustainability-enhancing technologies for pomace dewatering and separation, which constitute a mandatory stage in obtaining storage-stable by-products and final value-added commodities. A number of dryers and separators were considered for pre-treatment of wet grape marc and analysed in terms of their design characteristics, functionality, feasibility, throughput and efficiency. A multi-criteria decision analysis was carried out to compare, rank and select the equipment which is most suitable for the purpose. It was found out that the rotary drum dryer and the drum screen separator with internal blade rotor are the best candidates to fulfil the technology requirements, while the flowsheet that includes an initial separation followed by drying of the resulting fractions is a rather attractive option. Valorising grape waste worldwide contributes substantially to achieving the United Nations Sustainable Development Goals for responsible consumption and production, mitigating climate change, caring for health and well-being, preserving land life and combating hunger. Full article

Red mud, a highly alkaline industrial by-product generated during aluminum smelting, poses serious environmental risks such as soil alkalization and ecological degradation. In this study, response surface methodology (RSM) was integrated with advanced microstructural characterization techniques to optimize the performance of red mud–slag composite cementitious materials through multi-factor analysis. By constructing a four-factor interaction model—including red mud content, steel fiber content, alkali activator dosage, and calcination temperature—a systematic mix design and performance prediction framework was established, overcoming the limitations of traditional single-factor experimental approaches. The optimal ratio was determined via multi-factor RSM analysis as follows: the 28-day flexural strength and compressive strength of the specimens reached 12.26 MPa and 69.83 MPa, respectively. Furthermore, XRD and SEM-EDS analyses revealed the synergistic formation of C-S-H and C-A-S-H gels, and their strengthening effects at the fiber–matrix interfacial transition zone (ITZ), elucidating the micro-mechanism pathway of “gel densification–rack filling–strength enhancement.” This work not only enriches the theoretical foundation for the design of red mud-based binders but also offers practical insights and empirical evidence for their engineering applications, highlighting substantial potential in the development of sustainable building materials and high-value utilization of industrial solid waste. Full article

Anaerobic digestion for biogas production represents a crucial approach to achieving the high-value utilization of agricultural solid waste. The adoption of multi-material co-digestion offers a viable solution to overcome the inherent constraints associated with single-substrate digestion, thereby significantly enhancing the efficiency of resource utilization. This study explored a co-digestion system using dairy manure and cucumber vines as substrates, uncovering how total solids (TS) influence the methane yield and microbial community characteristics. All treatments exhibited swift methane fermentation, with daily production initially increasing before declining. Cumulative methane production increased with the increasing TS contents. These results may be linked to pH value and the concentration of volatile fatty acids (VFAs). Except for the 6% TS treatment, digesters across different TS levels maintained a favorable final pH of 7.4–8.4, while VFA concentrations exhibited a downward trend as TS contents increased. The treatment with the highest TS concentration (25%) demonstrated superior performance, achieving the maximum volumetric methane yield. This yield was 1.6 to 9.1 times higher than those obtained at low (6–10%) and medium (12–18%) TS concentrations. Microbial community analysis revealed that during the peak methane production phase, Firmicutes and Methanoculleus were the predominant bacterial and archaeal phyla, respectively. The microbial community structure changed with different TS levels. This study offers valuable scientific insights for enhancing biogas production efficiency in co-digestion systems. Full article

The treatment of antibiotic mycelial residue (AMR) has emerged as a critical challenge hindering the sustainable development of the biopharmaceutical industry. As a representative hazardous solid waste generated during antibiotic manufacturing processes, AMR may pose substantial risks to environmental safety. This review elucidates the properties and hazards of AMR while systematically reviewing current mainstream treatment technologies. Building upon the elucidation of underlying mechanisms, it further examines the application bottlenecks and research progress associated with different techniques. Through a comprehensive understanding of existing research achievements, this paper proposes future development strategies and perspectives for AMR treatment, highlighting that integrated multi-technology treatment approaches may represent the predominant developmental direction in this field. Full article

Carbon monoxide (CO) is a toxic pollutant emitted by municipal solid waste incineration (MSWI), which has a strong correlation with dioxins. In terms of the sustainable development of an ecological environment, CO emission concentration is strictly controlled by the environmental departments of various countries in the world. The construction of its prediction model is conducive to pollution reduction control. The MSWI process is affected by multi-factors such as MSW component fluctuation, equipment wear and maintenance, and seasonal change, and has complex nonlinear and time-varying characteristics, which makes it difficult for the CO prediction model based on offline historical data to adapt to the above changes. In addition, the continuous emission monitoring system (CEMS) used for conventional pollutant detection has unavoidable misalignment and failure problems. In this article, a novel prediction model of CO emission from the MSWI process based on semi-supervised concept drift (CD) detection in kernel feature space is proposed. Firstly, the CO emission deep prediction model and the kernel feature space detection model are constructed based on offline batched historical data, and the historical data set for the real-time construction of the pseudo-labeling model is obtained. Secondly, the drift detection for the CO emission prediction model is carried out based on real-time data by using unsupervised kernel principal component analysis (KPCA) in terms of feature space. If CD occurs, the pseudo-label model is constructed, the pseudo-truth value is obtained, and the drift sample is confirmed and selected based on the Page–Hinkley (PH) test. If no CD occurs, the CO emission concentration is predicted based on the historical prediction model. Then, the updated data set of the CO emission prediction model and kernel feature space detection is obtained by combining historical samples and drift samples. Finally, the offline history model is updated with a new data set when the preset conditions are met. Based on the real data set of an MSWI power plant in Beijing, the validity of the proposed method is verified. Full article

In the face of increasingly complex urban challenges, a critical question arises: can urban ecosystems maintain resilience, vitality, and sustainability when confronted with external threats and pressures? Taking Kunming—a plateau-mountainous city in China—as a case study, this research constructs an urban ecosystem resilience (UER) assessment model based on the DPSIR (Driving forces, Pressures, States, Impacts, and Responses) framework. A total of 25 indicators were selected via questionnaire surveys, covering five dimensions: driving forces such as natural population growth, annual GDP growth, urbanization level, urban population density, and resident consumption price growth; pressures including per capita farmland, per capita urban construction land, land reclamation and cultivation rate, proportion of natural disaster-stricken areas, and unit GDP energy consumption; states measured by Evenness Index (EI), Shannon Diversity Index (SHDI), Aggregation Index (AI), Interspersion and Juxtaposition Index (IJI), Landscape Shape Index (LSI), and Normalized Vegetation Index (NDVI); impacts involving per capita GDP, economic density, per capita disposable income growth, per capita green space area, and per capita water resources; and responses including proportion of natural reserve areas, proportion of environmental protection investment to GDP, overall utilization of industrial solid waste, and afforestation area. Based on remote sensing and other data, indicator values were calculated for 2006, 2011, and 2016. The entire-array polygon indicator method was used to visualize indicator interactions and derive composite resilience index values, all of which remained below 0.25—indicating a persistent low-resilience state, marked by sustained economic growth, frequent natural disasters, and declining ecological self-recovery capacity. Forecasting results suggest that, under current development trajectories, Kunming’s UER will remain low over the next decade. This study is the first to integrate the DPSIR framework, entire-array polygon indicator method, and Grey System Forecasting Model into the evaluation and prediction of urban ecosystem resilience in plateau-mountainous cities. The findings highlight the ecosystem’s inherent capacities for self-organization, adaptation, learning, and innovation and reveal its nested, multi-scalar resilience structure. The DPSIR-based framework not only reflects the complex human–nature interactions in urban systems but also identifies key drivers and enables the prediction of future resilience patterns—providing valuable insights for sustainable urban development. Full article

Three types of solid waste are produced during beer fermentation: spent grain, hot trub, and residual yeast. While the first is used as livestock feed, the seconds has not yet found any real reapplication in the field of circular economy. The aim of this work is to study and characterize these two brewing wastes, i.e., hot trub and residual yeast, to evaluate their potential reuse in the agricultural field. Samples from top-fermented and bottom-fermented beers were chemically investigated. Initially, the safety was assessed via multi-detection analysis of 57 mycotoxins, and all samples were deemed safe. Subsequently, the chemical and elemental composition was examined via ICP-MS and microanalysis, along with phenolic compounds and antioxidant activity via HPLC and spectrophotometric determinations, to achieve a thorough characterization of these waste samples. The C/N ratio of residual yeast from top-fermented beer and hot trub of the bottom-fermented one were near the optimal one (10:1). This research marks an initial step towards repurposing brewery waste materials as fertilizers. The subsequent steps will involve the formulation and field trials. Full article

The swift advancement of China’s mining sector has led to the generation of substantial amounts of industrial solid waste, which poses significant risks to the ecological environment. This study aims to investigate effective methods for utilizing industrial solid waste in the production of mine filling materials, thereby facilitating green mine construction and the efficient use of resources. The study employs the PRISMA methodology to conduct a systematic review of the pertinent literature, analyzing the current status, challenges, and developmental trends associated with the use of coal-based solid waste, smelting waste, industrial by-product gypsum, and tailings in filling materials. The findings indicate that, while the use of individual coal-based solid waste in filling materials shows promise, there is a need to optimize the ratios and activation technologies. Furthermore, the synergistic application of multi-source coal-based solid waste can enhance the overall utilization rate; however, further investigation into the reaction mechanisms and ratio optimization is required. Smelting slag can serve as a cementing agent or aggregate post-treatment, yet further research is necessary to improve its strength and durability. Industrial by-product gypsum can function as an auxiliary cementing material or activator, although its large-scale application faces significant challenges. Tailings present advantages as aggregates, but concerns regarding their long-term stability and environmental impacts must be addressed. Future research should prioritize the synergistic utilization of multi-source solid waste, performance customization, low-carbon activation technologies, and enhancements in environmental safety. Additionally, the establishment of a comprehensive lifecycle evaluation and standardization system is essential to transition the application of industrial solid-waste-based filling materials from empirical ratios to mechanism-driven approaches, ultimately achieving the dual objectives of green mining and the resource utilization of solid waste in mining operations. Full article

The preparation of low-cost and high-durability cement-based material systems using seawater mixing has become an urgent task in marine engineering construction. The requirements have addressed key challenges, including high transportation costs for fresh water and raw materials, poor structural durability, and difficulty in meeting actual construction schedules. Sulfatealuminate cement (CSA) has become an ideal material for marine engineering due to its high corrosion resistance, rapid early strength, which is 35–40 MPa of 3-day compressive strength and is 1.5–2 times compared ordinary Portland cement (OPC), and low-carbon characteristics, reduced production energy consumption by 35–50%, and CO₂ emissions of 0.35–0.45 tons/ton. The Cl⁻ and SO₄²⁻ in seawater can accelerate the hydration of CSA, promote the formation of ettringite (AFt), and generate Friedel’s salt fixed chloride ions, significantly enhancing its resistance to chloride corrosion. Its low alkalinity (pH ≈ 10.6) and dense structure further optimize its resistance to sulfate corrosion. In terms of environmental benefits, CSA-mixed seawater can save 15–20% fresh water. And the use of solid waste preparation can reduce environmental burden by 38.62%. In the future, it is necessary to combine multi-scale simulation to predict long-term performance, develop self-healing materials and intelligent control technologies, and promote their large-scale application in sustainable marine infrastructure. Full article

Waste-to-energy (WTE) is considered the most promising method for municipal solid waste treatment. An integrated energy system (IES) with carbon capture systems (CCS) and power-to-gas (P2G) can reduce carbon emissions. The incorporation of a “green-carbon” offset mechanism further enhances renewable energy consumption. Therefore, this study constructs a WTE-IES hybrid system, which conducts multi-dimensional integration of IES-WTP, CCS-P2G, photovoltaic (PV), wind turbine (WT), multiple energy storage technologies, and the “green-carbon” offset mechanism. It breaks through the limitations of traditional single-technology optimization and achieves the coordinated improvement of energy, environmental, and economic triple benefits. First, waste incineration power generation is coupled into the IES. A mathematical model is then established for the waste incineration and CCS-P2G IES. The CO₂ produced by waste incineration is absorbed and reused. Finally, the “green-carbon” offset mechanism is introduced to convert tradable green certificates (TGCs) into carbon emission rights. This approach ensures energy demand satisfaction while minimizing carbon emissions. Economic incentives are also provided for the carbon capture and conversion processes. A case study of an industrial park is conducted for validation. The industrial park has achieved a reduction in carbon emissions of approximately 72.1% and a reduction in the total cost of approximately 33.5%. The results demonstrate that the proposed method significantly reduces carbon emissions. The energy utilization efficiency and system economic performance are also improved. This study provides theoretical and technical support for the low-carbon development of future IES. Full article

A ternary geopolymer mortar (TGM) was synthesized using steel slag (SS), granulated blast furnace slag (GGBS), and fly ash (FA) as raw materials. The effect of the SS content (0–60%) and the GGBS/FA mass ratio (5:1 to 1:5) on the TGM’s setting time was studied. To address the issue of rapid setting, the impact of different mixing methods ((A) dry mixing, (B) pre-dissolution, and (C) pre-coating) and dosages of BaCl₂ on the setting and hardening properties of TGM was further explored. The hydration product evolution and microstructural characteristics were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS), with an in-depth analysis of the retarding mechanism of BaCl₂. The results indicate that, as the steel slag content increases, the setting time of TGM significantly shortens. The setting time decreases slightly with an increase in the GGBS/FA mass ratio. The mixing method influences the retarding effect of BaCl₂, with the C method showing significant advantages over both the A and B methods. Under the C mixing method, BaCl₂ consumes the alkaline components (SiO₃²⁻) in the alkaline activator and forms a BaSiO₃ coating layer on the precursor surface, which further delays the hydration process of the precursor particles. This study provides a promising approach for the high-value utilization of multi-source solid waste and suggests that future research should focus on large-scale application strategies and long-term performance evaluation to support its practical use in sustainable construction. Full article