Through the statistical analysis of papers and patents, the progress of research and the evolving trend of technological innovation capacity in China and other countries’ solid waste treatment were summarized. Over the past two decades, China’s research on solid waste treatment has achieved a leap-forward development, with remarkable breakthroughs from basic research to technology application. In terms of research papers, China has gradually become the dominant force in the world after following the initial phase, with the number and quality of papers rapidly improving, and the international cooperation network expanding, especially the academic cooperation with the United States, Australia and other countries. However, the proportion of highly cited papers has fluctuated in recent years, and the quality of research needs to be strengthened. In the field of technological patents, the number of patent applications in China has grown explosively, far exceeding other countries. Although China has an advantage in the number of patents, the proportion of high-value patents is still lower than that of the United States and Japan. The overall conversion rate of patents is low, and a large number technological achievements have not yet been industrialized and applied, which highlights the lack of industry-academia-research collaboration and market-oriented promotion. The international competitive pattern shows trend of “East rising, West falling”, and China has gradually replaced the traditional technological dominance of the United States, Japan, and Europe. Through policy-driven, scientific research investment and industry synergy, China has formed an innovative closed loop. In the future, it is necessary to strengthen the connection between basic research and engineering transformation, improve the quality and conversion efficiency of patents, and deepen international technology collaboration， in order to consolidate the leading position in the global solid waste treatment field, and furthermore, support the construction of “zero-waste city” and the goal of circular economy.

Driven by the global green transition and the dual-carbon strategy, solid waste governance is undergoing a profound transformation from end-of-pipe treatment to high-value resource recovery, life-cycle risk control, and intelligent management. Based on references data from the past decade, patent data from the past two decades, and multidimensional evidence on institutional collaboration and regional distribution, the research hotspots and technological trajectories in the field of international solid waste governance were systematically reviewed. The results indicated that the number of relevant references had grown at an average annual rate of about 11% over the past decade, with China, India, and the United States ranking among the top in publication volume, and China ranking first globally in the number of highly cited papers. Patent analysis showed that global patent activity in solid waste governance had steadily increased over the past twenty years, with China leading in application volume, particularly in incineration, landfill monitoring, sorting equipment, and material reutilization. However, gaps remained in advanced equipment, precision sensing, and the efficient treatment of complex waste streams. Institutional and regional collaboration revealed a “multi-core and multi-regional” structure, with research hotspots increasingly focusing on the circular economy, digitalization, and risk prevention. Intelligent recognition, high-value resource recovery, and coordinated pollution and carbon reduction have become key directions. Overall, China has made notable progress in bulk industrial solid waste utilization and hazardous waste treatment, but it remains urgent to establish a technology system centered on fundamental theories and key innovations to advance high-quality development and risk control. In view of global trends, this study proposes strengthening intelligent governance, achieving breakthroughs in core technologies, and promoting synergy between resource utilization and carbon reduction, thereby providing a reference for building a globally competitive solid waste governance model.

Solid waste management is of great significance for promoting the green transformation of the economy society, achieving the “dual carbon” goals and building a “waste-free society”. This study focused on five typical solid wastes in China, namely general industrial solid waste, urban and rural domestic waste, agricultural solid waste, construction waste and hazardous waste. It systematically reviewed their generation scale, structural composition and regional distribution characteristics, analyzed the current status and shortcomings of utilization and disposal, and proposed directions for collaborative governance. The study found that the structure of solid waste generation in China varied significantly. In 2023, the total generation of the five types of solid waste in China was 9.32×109 t, with general industrial solid waste amounting to 3.80×109 t, among which tailings and other five types accounted for 62.5%; kitchen waste accounted for 57.78% of urban and rural domestic waste; livestock and poultry manure accounted for 75.9% of agricultural solid waste; construction waste was dominated by engineering soil (accounting for 67.2%); hazardous waste showed a diverse small category distribution due to the industrial structure, reflecting the resource consumption and waste output patterns in different fields. Moreover, it has the characteristics of regional distribution and associated development. The spatial pattern of solid waste is closely related to industry, population and development stage. General industrial solid waste is concentrated in northern resource-based and heavy chemical industrial provinces; urban and rural domestic waste is mainly generated in economically developed and densely populated areas; construction waste is highly concentrated in provinces with rapid urbanization; the distribution of hazardous waste is associated with industrial density, showing a distinct spatial agglomeration. In addition, the utilization and disposal of solid waste have both achievements and shortcomings. The comprehensive utilization rate of general industrial solid waste reached 57.9%, but the utilization rate of tailings was only 25.6%; the utilization rates of different small categories of hazardous waste varied greatly, such as HW48 (80.2%) and HW18 (less than 3%); the resource utilization rate of urban and rural domestic waste reached 78.4%, but the treatment of kitchen waste, combustible waste and hazardous waste was difficult; the utilization rate of livestock and poultry manure in agricultural solid waste was 93.4%, but the utilization rate of agricultural film waste was only 37.7%, with the shortcomings stemming from technical, facility and recycling network bottlenecks. Based on this, it is proposed to carry out full-chain collaborative governance from three directions: source reduction, energy utilization and improvement of secondary pollutant control and regional coordination capabilities, to help break through the bottlenecks in solid waste management, provide support for precise policy-making and promote the transformation of the governance model towards reduction, resource utilization, low carbonization and risk controllability, and serve the “dual carbon” goals and the construction of a “waste-free society”.

Smelting slag has been an important area of solid waste research due to the potential environmental risks associated with long-term stockpiling, coupled with its resource property characteristics. In this study, relevant literature published on China Knowledge Network (CNKI) and Web of Science (WoS) in the past 20 years was analyzed using CiteSpace software, and relevant patents in this field in the past 10 years were searched in combination with Incopat database, so as to visualize the hotspots and cutting-edge trend of smelting slag research. The results showed that the amount of literature and patents have generally shown an increasing trend year by year, with China taking the first place in terms of the number of related literature and patents, Australia ranking second in terms of published literatures and South Korea ranking second in terms of the patent numbers. The centrality of the United States is the highest, reaching 0.79, still dominating the field, indicating that China has a high amount of publications, but its core competitiveness and influence are insufficient. The analysis of patented technology fields showed that the technology focus was highly concentrated on the two major paths of valuable metal recycling and building materials utilization (such as cement, ceramics, refractory materials). The analysis of hotspots showed that the research hotspots of the literature and patents were basically the same, mainly focusing on the recycling and comprehensive utilization of valuable heavy metals and the morphology analysis of heavy metals in the leaching solution, with global characteristics. The difference is that the WoS database literature has began to focus on the combination of numerical simulation and other intelligent technologies with this field. Based on the double validation of patents, literature data and policy-driven, the key directions for future research in the field of smelting slag include: precise dissociation and efficient extraction of valuable metals such as Li, Ti, Ni and Cu; research and development of synergistic in-situ solidification/stabilization technology of multiple heavy metals in historical stockpile slag, and new green, low-carbon and economic stabilization technology for increased smelting slag; materialization and high-value utilization based on pollution and carbon reduction synergy; prediction of smelting slag characteristics and process optimization based on numerical simulation, artificial intelligence and other intelligent technologies, and strengthening the integration of numerical simulation, artificial intelligence and other computer sciences with materials science, biology and other disciplines.

Heavy metals have caused varying degrees of soil pollution in municipal solid waste (MSW) landfills. To better investigate, assess, and remediate heavy metal pollution in landfill soils, this study took sanitary MSW landfills, simple landfills, temporary dumping sites, and waste transfer stations as research objects. Methods including the Nemerow Pollution Index method (PI), Potential Ecological Risk Index method (RI), Risk Assessment Code method (RAC), and mathematical statistics were adopted, to analyze the pollution status, speciation, and influencing factors of heavy metals (Fe, Mn, Pb, Cd, Cu, Hg) in the soils. The results showed that cadmium (Cd, PI = 0.57-2.61) and mercury (Hg, PI = 0.62-2.70) were the main heavy metal pollutants in the landfill soils, with 25.0%-83.3% and 33.3%-100.0% of the sampling sites exceeding the soil risk screening values, respectively. The heavy metals including Fe, Pb, Cd and Cu had a main form of residual state (33%-96%), and the Mn had a main form of Fe-Mn oxidation state (34%-65%)， the Risk Index (RI) values of different types of landfill sites ranged from 63.83 to 147.85. Therefore, the type of landfill site exerts a significant impact on the total content and speciation of heavy metals in soil. In the daily management of landfill sites, emphasis should be placed on the pollution prevention and control measures for MSW transfer stations (RI = 147.85), simple landfill sites (RI = 147.55), and temporary dumping site A (RI = 119.56).

Under the dual impacts of the implementation of mandatory waste classification policies and COVID-19 prevention and control, the actual domestic waste removal and transportation volume in megacities has shown significant volatility and structural changes in recent years, posing challenges to traditional prediction methods. Taking Guangzhou, a megacity in the Pearl River Delta region, as an example, four key driving factors with strong anti-interference to historical data fluctuations were identified using the grey relational analysis method based on statistical data of domestic waste removal and transportation volume and related factors over the years. These factors were per capita consumption expenditure, per capita gross domestic product, permanent population, and urban built-up area. Meanwhile, to capture the impact of social events, mandatory domestic waste classification policy implementation and epidemic prevention and control were introduced as dummy variables into the multi-dimensional grey system prediction model GM(1,6). The model predicted the future waste removal and transportation volume under four scenarios: strong classification without epidemic, no classification without epidemic, strong classification with epidemic, and no classification with epidemic. The results showed that compared with GM(1,1) and GM(1,4) models, the GM(1,6) model had significantly improved accuracy and fitting effect. Mandatory classification policies and the epidemic have achieved obvious effects in reducing waste removal and transportation volume. Under the strong classification scenario, the growth rate of waste removal and transportation volume is more moderate, reaching 7.415 4 million tons by 2035, which is 9% lower than the 8.158 8 million tons under the no-classification scenario. This reflects the long-term effect of source reduction and effectively supports the system planning and governance strategies of domestic waste in megacities in the “waste classification era”.

The physical and chemical properties of domestic waste are important criteria for selecting waste terminal treatment methods and assessing pollution potential. Based on the sampling data of source and terminal garbage in a city in South China in the past five years, the changes in its components and characteristics were compared and analyzed. The results showed that the average annual growth rate of domestic waste removal from 2015 to 2019 was 6.96%, and after the implementation of waste classification, the average annual growth rate decreased to 0.18% from 2020 to 2024. From 2020 to 2024, among the physical components of source residual waste, food waste accounted for the highest proportion (41.55%-51.43%),showing a fluctuating downward trend. It was followed by rubber and plastic waste (21.85%-31.69%), showing an increasing trend. While paper waste (10.99%-20.93%) and textile waste (2.30%-7.78%) showed fluctuating changes. The proportion of food waste in terminal domestic waste (49.55%-59.40%) had slightly increased year by year, while rubber, paper, textile and glass had all fluctuated and decreased. The moisture content of the source residual waste (48.51%-56.05%) was lower than that of the terminal domestic waste (56.66%-60.73%), while the low calorific value on a wet basis (7 750-10 876 kJ/kg) was higher than that of the terminal domestic waste (6 126-6 701 kJ/kg). The dry-basis contents of Hg, Pb, Cd, total Cr and As in the terminal domestic waste were all higher than those at the source. Therefore, waste must be properly classified at the source. Only in this way, the migration of water can be effectively prevented during the processes of collection, transportation and disposal, and the migration and re-adsorption of heavy metals can be reduced, so as to better achieve resource utilization.

The physicochemical characteristics of food waste were of great significance for selecting suitable treatment technology, evaluating environmental impacts, and realizing resource utilization. The physicochemical characteristics of household food waste from source classification and mixed waste in a city of South China were analyzed, and compared with the physicochemical characteristics of restaurant food waste and other food waste. The results showed that the moisture content of all three types of food waste was high, and the carbon-nitrogen ratio was low. Therefore, dehydration and carbon-nitrogen ratio adjustment were necessary before biochemical treatment. The moisture content of the source-segregated household food waste (75.08%) was the lowest and carbon-nitrogen ratio (19.73) was the highest among the three types of food waste. The fat and protein of the source-segregated household food waste were 10.06% and 18.71%, respectively. While those of restaurant food waste were higher, at 27.16% and 25.76%, respectively. The total nutrient content of the three types of food waste all met the limit requirement of NY/T 525—2021 Organic Fertilizer, and the content of heavy metals was all below the limit value of the relevant pollution evaluation standard. The food waste in a city of South China was rich in organic matter and nutrients, with a low risk of heavy metal pollution and high potential for resource utilization.

To promote the resource utilization of engineering waste soil (EWS) and enhance the comprehensive performance of magnesium oxychloride cement (MOC), the effects of EWS incorporation (0, 20%, 40%, 60%), moisture content (0, 10%, 20%, 30%), and carbonation curing on the flexural strength, compressive strength, and water resistance of MOC were investigated. Experimental results demonstrated that the incorporation of 20% EWS achieved optimal mechanical properties and water resistance of MOC, with a 28 d compressive strength increase of 2.34% and the softening coefficient improvement of 3.8%. When the incorporation amount was elevated to 40%, the compressive strength exhibited only a marginal decrease (0.88%), but the utilization rate of engineering waste soil was significantly improved. Moisture content exerted a notable adverse effect on mechanical performance. Specimens with 30% moisture content showed an 11.6% reduction in compressive strength compared to dried samples, attributed to particle agglomeration induced by water molecules. Carbonation curing enhanced compressive strength by 11.71%-16.54% through pore-filling effects via magnesium carbonate flocs. Furthermore, the synergistic interaction between waste soil incorporation and carbonation curing substantially improved water resistance, yielding a softening coefficient of 0.88 (11.4% increase compared to uncarbonized group) for 20% waste soil-incorporated specimens after carbonation. The results of this study can provide important data support for the application of magnesium oxychloride cement materials in solid waste resource utilization and low-carbon environmental protection.

As an important component for achieving the “dual carbon” goals and establishing “zero-waste cities”, the resource utilization of decoration waste has emerged as a critical pathway for urban sustainable development. This study focused on a representative decoration waste recycling enterprise in Zhejiang province, developing a precise carbon footprint accounting model for decoration waste resource utilization using the Process-based Life Cycle Assessment (PLCA) methodology. The accounting model systematically quantified carbon emissions at each stage of resource utilization (in terms of carbon dioxide equivalent), and identified key factors that affect the carbon footprint through sensitivity analysis. Results revealed that the decoration waste resource utilization process could be divided into six distinct stages: transportation, production, recycling, resource recovery, incineration, and landfilling. The treatment of one metric ton of decoration waste yields a net carbon reduction of 242.58 kg, demonstrating significant carbon reduction benefits. The production stage is the primary source of carbon emissions (57.62 kg), while the recycling and incineration stages are key contributors to carbon reduction (?178.42 kg and ?96.09 kg, respectively). The calorific value of combustibles, carbon emission factors of recycled products substituting construction materials, and the contents of concrete, bricks and combustibles were identified as key parameters influencing the carbon footprint of decoration waste resource utilization. To enhance carbon reduction efficiency of the resource utilization of decoration waste, this study suggested implementing source separation controls, improving sorting precision, and developing high-value recycled products.

An engineering case of rapid recovery using the “commissioning under load” strategy for a denitrification-nitrification (DN) system treating leachate at a waste incineration plant in Zhejiang province was introduced, following system collapse due to high-load shock. Faced with the operational constraints of a DN system failure caused by high ammonia nitrogen load (NH3-N concentration: 600-800 mg/L) in the leachate treatment system and the lack of an off-site transportation option, a progressive on-load debugging scheme was implemented. Key factors including water quality indicators (CODCr，NH3-N，pH) and environmental parameters (dissolved oxygen, temperature) were intensively monitored. The results demonstrated that the collapsed DN system could successfully regained functionality within 20-30 days using this strategy and progressively achieved stable operation (NH3-N removal rate>95%). This study provides a replicable technical reference for the rapid recovery of biological systems subjected to high ammonia nitrogen shock under similar operating conditions.

This study designed a carbon capture pilot-scale system platform with an annual capacity of 1 000 tons based on the flue gas from a biomass fluidized bed boiler, utilizing a “bubbling bed adsorption + vacuum heating desorption” process. The system includes subsystems for flue gas pretreatment, CO2 adsorption, pneumatic conveying, CO2 desorption, and electrical control, all arranged in a skid-mounted configuration. Operational results showed that the system’s flue gas inlet flow rate was 550-650 m3/h with a CO2 concentration of 12%-15%. After adsorption, the outlet CO2 concentration was 0.15%, achieving a CO2 capture and recovery rate of 98.95%, meeting the design requirements. In terms of energy consumption, the system had a total installed power of 110.5 kW, with a regeneration thermal energy consumption of less than 2.07 GJ/t, lower than that of traditional amine-based technologies. The system can operate continuously, the operation is simple, and does not suffer from equipment corrosion or ammonia escape issues. It provides practical reference for the development of the second-generation carbon capture technologies.

With the continuous tightening of air pollutant emission standards in China, traditional end-of-pipe control focusing on single pollutants can no longer meet the dual requirements of ultra-low emissions and cost control. Based on this, a multi-pollutant cooperative optimization system for typical large-scale industrial combustion sources was designed and implemented. The system integrated denitrification, dust removal and desulfurization units. A long short-term memory network was employed to develop multi-pollutant prediction models, and an operational cost model was established considering electricity and reagent consumption. Under emission and equipment constraints, particle swarm optimization and differential evolution algorithms were applied for global optimization. A case study on a power unit in Zhejiang province showed that the proposed method ensured stable compliance with SO2, NOx, and particulate matter standards, while reducing operational costs by 10%-20% on average across different load conditions. The results confirmed the engineering feasibility of the approach and highlighted its practical value for energy saving and emission reduction in large industrial combustion sources.

Due to the complexity and variability of control parameters in the incineration process, it is difficult to quickly identify the most critical control parameters during manual operation. XGBoost-SHAP is often used for interpretability analysis of machine learning models and can analyze the importance ranking of specific features relative to predicted values. In this study, operational data of the co-incineration of biogas residue, leachate, and sludge were collected from a grate-type incinerator at an actual municipal solid waste incineration power plant. By actively adjusting parameters commonly regulated in industrial practice (such as air flow rate and grate residence time), the XGBoost-SHAP importance interpretation method was employed to analyze the effects of parameter adjustments on the main steam flow rate and gaseous pollutant emissions. The results indicated that the furnace temperature and total air flow rate had the most significant impact on the main steam flow rate. The secondary air flow rate exerted the greatest influence on NOx concentration, and the co-incineration of leachate had the most pronounced effect on parameter variations, followed by sludge and biogas residue. This study clarified the priority order of potential relationships among regulatory parameters during the combustion process. Furthermore, by integrating real-time operational data with principal component analysis, it identified positive and negative correlations among various parameters, offering valuable references for practical engineering operations.