To assess the co-firing adaptability of the oversize fraction of aged landfill waste (AG) in a mechanical-grate municipal solid waste incinerator, a coupled FLIC-Fluent model was developed for an 850 t/d unit, with AG blending ratios ranging from 0 to 70%. Combustion stability was compared for co-firing AG with high-calorific-value municipal solid waste (MSW-A) and conventional municipal solid waste (MSW-B). Using MSW-A as the representative base waste, NOx formation and selective non-catalytic reduction (SNCR), fly-ash erosion, and high-temperature chlorine corrosion were further investigated. The results showed that with the increase of AG blending ratio, the lower heating value of the mixed waste reduced, the ignition position delayed, the furnace temperature and high-temperature gas residence time decreased, and local low-temperature zones enlarged. Optimizing the secondary-air injection angle improved local gas mixing and temperature-field uniformity. For MSW-A, the increase in NOx concentration with AG blending was consistent with the enhanced influence of fuel-nitrogen input, but the contributions of individual NOx formation pathways were not quantitatively separated. After selecting the appropriate injection level for each case according to the 850-1 050 ℃ temperature window, SNCR using 15% aqueous ammonia resulted in model-predicted NOx concentrations below 200 mg/m3, with predicted removal efficiencies ranging from 31.5% to 58.0%. These differences were jointly affected by the temperature field, injection level, and gas-mixing conditions rather than directly caused by AG blending. Severe fly-ash erosion was mainly located at the contraction of the second flue and the rear wall of the third flue. Although AG blending increased the HCl concentration, the accompanying decrease in furnace temperature reduced the predicted corrosion rate on some heating surfaces, while Wall 3 exhibited the highest corrosion risk. Considering combustion stability, NOx control, fly-ash erosion, and high-temperature chlorine corrosion, the recommended AG blending ratio for MSW-A was no more than 30% under the investigated furnace and fuel conditions. For MSW-B, which was evaluated only in terms of combustion stability and high-temperature combustion conditions, the AG blending ratio should be limited to 20%. The results are intended for relative trend analysis and engineering risk screening under the investigated conditions.

The layout of urban waste cooking oil (WCO) pretreatment facilities critically determines the efficiency of collection and transportation as well as operational costs. It is a key link in connecting the entire chain of “production, collection, transportation, treatment and utilization”, and also the core support for achieving resource recycling. Taking Beijing as a case study, a site selection optimization model integrating spatial gridding and network location allocation was constructed. Firstly, the catering Point-of-Interest (POI) data were aggregated into a 500 m×500 m regular grid to characterize the spatial heterogeneity of demand. Secondly, a road network dataset with travel time as impedance was constructed based on the actual road network data, and the differentiated service time thresholds (30 minutes in the central urban area, 45 minutes in the plain new towns, and 60 minutes in the ecological conservation area) were set according to the urban functional zones. Finally, to balance system efficiency and service equity, the residual-demand P-median model (RPM) was employed to minimize total transport impedance and a capacitated maximal covering location model (CMCLM) was introduced to maximize coverage under capacity constraints, to carry out multi-scenario optimization solution. The results revealed that the three existing facilities could cover only 44.11% of the city’s demand under the capacity-constrained service threshold of 16 minutes, exposing a significant service deficit in the northern region of Beijing. Three highly robust nodes of Changping Asuwei, Chaoyang and Haidian were consistently identified across both models, forming a rationalized collection network with the existing facilities. The marginal benefits of the newly added facilities exhibited diminishing returns, with two to three new facilities representing the optimal increment range in the near future, while with three new facilities could basically eliminate the blind spots throughout the region. The research showed that the differentiated threshold approach and the assignment of facility weights effectively balanced the transportation efficiency and spatial equity. The grid-network coupling method based on ArcGIS can significantly improve the computational efficiency while ensuring accuracy, providing a replicable decision-support for the refined layout of environmental sanitation facilities in megacities.

An automatic combustion control (ACC) system based on fuzzy PID control was proposed in this study. The control strategy incorporated modules of evaporation amount control, layer thickness control, air flow control, and oxygen content control. By adjusting primary and secondary air supply rates, feed rate, and furnace stroke, the automatic combustion control of municipal solid waste incinerators was realized. Trial operation results indicated that the relative standard deviation of evaporation amount decreased from 5.07% to 2.80%, with a deviation rate of 0.49%. The relative standard deviation of oxygen content variation decreased from 16.17% to 13.13%, with a deviation rate of 3.37%. This fuzzy PID-controlled ACC system could effectively improve the stability of evaporation capacity and the control accuracy of oxygen content, enhance the system’s adaptability to heating value fluctuations, improve the operation economy of municipal solid waste incinerators, and successfully realize stable combustion in waste incinerators. All production indicators meet the standards for stable operation of power plants.

Waste incineration has become a key technology for the efficient treatment of domestic waste. To enhance incineration efficiency and reduce pollution, precise control of the combustion-supporting air in the incinerator has become a key research direction. The study proposed a combustion-supporting air control system for waste incinerators that integrated an automatic combustion control (ACC) system with artificial intelligence (AI). Through utilizing model predictive control (MPC) technology, the system achieved dynamic regulation of the combustion-supporting air, addressed the lag issues inherent in traditional proportional-integral-derivative (PID) control. MPC models are versatile and can directly handle the control of processes with pure lag. It has excellent tracking performance, strong disturbance resistance capability and high robustness. After the system acquired the evaporation volume and combustion parameters of the waste incinerator in real time, it used MPC model to predict the future frequency of the fans, and precisely regulated the air volume in each area through ACC to achieve efficient combustion control. Results showed that this system significantly improved the stability of the combustion process. After implementation, the discrete coefficients for main steam flow, boiler outlet oxygen content, and the temperature in the upper part of the burnout zone were reduced to 5.33%, 16.33%, and 6.10%, respectively, while the operational frequency of the air system equipment decreased by 87.06%.

The disposal of three-phase centrifugal solid residue from food waste treatment facilities presents considerable challenges, and its resource utilization pathways remain limited. This study took the three-phase centrifugal solid residue produced by a kitchen waste treatment plant in Shenzhen as the object, and carried out a continuous operation test of integrated aerobic composting to investigate the operational stability of this technical route, the material reduction effect, and the potential for fertilizer utilization of compost products. A 25-day continuous operation trial was conducted under preset conditions, including intermittent mechanical agitation, forced aeration, auxiliary heating, and the addition of a composite microbial inoculant at a dosage of approximately 1 kg/t. The composting temperature was maintained within the range of 50-60 ℃, and the aeration rate was set at approximately 250 m3/h. During the 25-day continuous operation, the system exhibited stable performance. For the steady-state period from day 15 to day 25, the average daily output was (2.81±0.20) t, and the average mass reduction rate reached 73.8%±1.7%, demonstrating that the three-phase centrifugal solid residue could be continuously and stably reduced in volume under the aforementioned process conditions. After sieving with a 3 mm sieve, the obtained compost product had a moisture content of approximately 12.3%±0.7%. The total nutrient content (N+P2O5+K2O), pH, and heavy metal concentrations all complied with the requirements of NY/T 525—2026 Organic Fertilizers. Seed germination tests revealed that the germination rates of cucumber and carrot seeds treated with 1% and 10% compost extracts were higher than those of the blank controls, with germination indices reaching up to 174.25%±1.21% and 188.93%±15.00%, respectively. These results indicated a satisfactory degree of maturity and the absence of significant phytotoxicity in the composted products. Preliminary economic analysis indicated that the direct operating cost of this process was 35.36 RMB/t relying on the existing public utilities in the factory area, which was lower than the cost of off-site incineration disposal (100 RMB/t). Collectively, this study validated the engineering feasibility of the integrated aerobic composting route for three-phase centrifugal solid residue treatment in terms of continuous operation performance, mass reduction efficacy, product quality, and economic viability. The findings can provide a valuable reference for the reduction and fertilizer-oriented disposal of three-phase centrifugal solid residue in food waste treatment plants.

With the implementation of plastic ban policies and the construction of facilities for the resource utilization of food waste, the collaborative treatment of compostable plastics and food waste will inevitably increase. However, there are distinct differences between the standard test conditions for compostable plastics and the actual operating conditions of food waste treatment, and its engineering applicability needs to be verified. This study used compostable plastic bags with a PLA/PBAT/TPS mass ratio of 30∶50∶20. Two practical scenarios were simulated: crushed plastics directly mixed with food waste for aerobic fermentation, and a small amount of plastic residues from enzyme-enhanced pretreatment remaining in food waste for composting. The results showed that in the former scenario, the plastics wound around the stirring shafts of biological treatment equipment. Moreover, the plastics could not be effectively degraded within 9 to 18 months in either household static compost bins or industrial composting systems, indicating severe degradation lag and poor engineering applicability. In the latter scenario, the enzyme-enhanced plastics caused no disturbance to the composting process. After 96 days of composting, the average mass loss rate of individual plastic pieces in a specific calculation method was above 90%. All indexes of the finished compost demonstrated good engineering applicability. Nevertheless, results from scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG) showed that the main chain skeletons of PLA and PBAT in the visible plastic fragments remained intact without fundamental damage.

Non-co-digestion kitchen waste resource utilization projects often suffer from prolonged low-load operation due to complex acceptance procedures. The resulting operational stability and economic difficulties of the projects are common across the industry, yet systematic research on the full-process slurry treatment characteristics under such conditions remains lacking. Based on the operational data of a 660 t/d project in Nanjing in 2025, the organic matter distribution, anaerobic digestion performance, carbon source dependence of the biochemical treatment system, and operating costs of the slurry under low-load conditions were investigated. The results showed that approximately 0.89 m3 of slurry was produced per ton of feedstock. The slurry was acidic, with a pH ranging from 3.51 to 4.99. Owing to its high solids content, the total chemical oxygen demand (TCOD) was about 40% higher than the soluble chemical oxygen demand (SCOD), with values of （112 859.32±5 861.25） mg/L. Therefore, TCOD was preferable for expressing the organic loading. The continuous stirred tank reactor(CSTR) operated stably even at an organic loading rate far below the design value, achieved a TCOD removal efficiency of 93.13%±1.3%. While biogas production and methane concentration remained at normal levels. However, the excessively long hydraulic retention time caused the B/C ratio of the anaerobic effluent to drop below 0.2, which made nitrogen and phosphorus removal highly dependent on external carbon source addition. The carbon source cost accounted for over 50% of the direct cost of wastewater treatment. The overall direct cost of slurry treatment was 65.99 RMB/t. The loss of volumetric efficiency induced by low-load operation was the primary cause of the poor economic performance.

Taking a 150 t/d kitchen waste treatment project as an engineering case, this study investigated the upgrading and reconstruction of the pretreatment process to address the drawbacks of the original “thermal hydrolysis + high-pressure pressing” pretreatment process, including poor operating environment for grab bucket operation and excessive residue yield, as well as to improve the project’s operational economy. The project was completed and put into operation in 2021, and the project completed a technological renovation from March to June 2023. A hydraulic pulping unit was added before the high-pressure pressing section based on the original thermal hydrolysis process, forming an improved pretreatment process system of “thermal hydrolysis+hydraulic cyclone pulping+high-pressure pressing”. The improved process effectively enhanced organic matter separation and pretreatment purification performance of kitchen waste. Operational data showed that after the renovation, the thermal hydrolysis steam consumption per ton of kitchen waste was reduced from 150-200 kg to 110 kg.The output proportion of pretreatment residues decreased from 18%-20% to about 12%,and the direct operating cost was reduced by 11 RMB per ton of kitchen waste. The proposed technological renovation effectively addresses the operational defects of the traditional thermal hydrolysis pretreatment process, significantly improves the operational stability and resource utilization efficiency of the kitchen waste pretreatment system, and greatly reduces operation energy consumption and processing costs. This study provides reliable engineering references and technical support for the upgrading and renovation, energy-saving transformation and process optimization of similar kitchen waste pretreatment projects.

Aiming at the problem of treating biogas slurry generated from wet anaerobic fermentation in China’s biogas projects, a technical route of biogas slurry membrane concentration + microbial fermentation for fertilizer production was proposed. Taking a pig manure biogas project in Tongren city, Guizhou province as a case study, through multistage filtration (microfiltration + ultrafiltration + nanofiltration + reverse osmosis) combined with aerobic fermentation technology, the biogas liquid was concentrated six times and converted into high-value liquid fertilizer. The concentrated slurry met the requirments of GB 5084—2021 Standard for Irrigation Water Quality. Product testing demonstrated that the contents of organic matter, humic acid and total nutrients in the concentrated fertilizer were (55.00±1.20) g/L, (10.63±0.25) g/L, and (9.89±0.16) g/L， respectively, far exceeding the requirements of GB/T 40750—2021 Biogas Slurry for Agricultural Use. Heavy metals were either undetectable or below limits, and pathogenic microorganisms, the water-insoluble substance content and odor emission concentration complied with the requirements of GB/T 40750—2021. Field trials showed that by applying concentrated biogas slurry fertilizer through drip irrigation 10 times, each at a dosage of 75 kg/hm2 with a 10-day interval, the sugarcane yield reached 147.15 t/hm2, which was 19.20% higher than that of the chemical fertilizer group, the sucrose content increased by 6.70%, resulting in an average additional income of 34 590 yuan per hectare.Techno-economic analysis confirmed that the investment payback period of the project was only 2.18 years, and it has both environmental benefits and profit potential, providing a feasible path for the resource utilization of biogas slurry in large-scale biogas projects.

The chicken manure treatment center of Shanghai Chuandong farm has a treatment capacity of 165.0 t/d, and adopts the trough-type aerobic composting mode in design. The limit indicators for organic matter content, total nutrient content and heavy metal content of the compost product are required to meet the standard of NY/T 525—2021 Organic Fertilizer. Novel technologies including novel anti-corrosion, stepped aeration with porous bricks, and multi-linked automatic control are adopted in the design of the chicken manure treatment center, which solves the problems of anti-corrosion of the steel structure for aerobic fermentation, stepped aeration of fermentation troughs, and insufficient oxygen supply to the compost body. The evaluation results of the trial operation showed that the aeration rates per cubic meter of compost body in the temperature-increasing stage, high-temperature stage and cooling-down stage of the fermentation trough were 0.1~0.2 m3/min, 0.2~0.3 m3/min and 0.1~0.2 m3/min, respectively. The oxygen content of the compost body was higher than 8%, and the NH? content in the fermentation compost body was lower than 80 mg/m3, all of which met the design requirements. The initial adhesion, sealing performance and anti-corrosion performance of the steel structure of the fermentation plant were good. After the test specimens underwent 48 hours of continuous neutral salt spray testing with 5% concentration, no rust, white spots or corrosion phenomena were observed.

Co-combustion of organic solid waste in coal-fired boilers is an effective approach to realize low-carbon development of coal power. This paper systematically reviewed the research progress regarding stable combustion and pollution control during co-combustion of organic solid waste in coal-fired boilers. The combustion characteristics of various organic solid wastes, co-combustion modes, and their impacts on boiler operation and pollutant formation were analyzed. Special attention was paid to the generation and emission characteristics of typical pollutants under co-combustion conditions, the influences of co-firing parameters on flue gas purification systems together with corresponding regulation strategies, as well as the physicochemical properties and resource recovery pathways of fly ash generated after co-combustion. Co-combustion delivers prominent carbon reduction benefits: every 5% increase in biomass blending ratio cuts coal consumption by 1.0-3.0 kg per ton of steam produced, yet the blending ratio should not exceed 20%. Nevertheless, co-combustion brings notable risks of “pollution transfer”. Co-firing biomass tends to raise alkali metal contents in fly ash and increase PM1 emissions. Co-firing sewage sludge elevates heavy metal concentrations in flue gas, while co-firing high-chlorine organic solid waste significantly raises the formation risks of hydrogen chloride (HCl) and dioxins. Targeted countermeasures including blending ratio adjustment, temperature control and air distribution optimization are required for regulation. This review can provide theoretical references and technical support for the clean and efficient application of organic solid waste co-combustion technologies in coal-fired boilers, facilitating the green transition of coal power and energy recovery of organic solid waste.

Traditional grab-crane weighing systems in municipal solid waste incineration power plants suffer from measurement delays and cumulative errors of 3%-5%, leading to deviations in the calculated furnace-feeding waste amount and limiting the accuracy of real-time combustion-condition regulation. In this study, a real-time combustion adjustment method based on the dynamic coupling of grate speed and waste-bed thickness was developed. A multi-parameter coupling model incorporating effective grate area, waste-bed thickness, waste bulk density and grate speed was established to optimize the coordinated control strategy for combustion air distribution and grate operation. In addition, the correlation characteristic between air-pressure differential and waste-bed thickness was used to realize advanced prediction and regulation of the combustion process. Practical verification showed that, after application of the proposed method, the power generation per ton of waste increased by 14.03 kWh. Based on the furnace-feeding waste amount in a comparable statistical period, the equivalent additional power generation was estimated to be 9.308 9×106 kWh. The power generation efficiency increased from 21.71% to 25.12%, corresponding to a relative increase of 15.71%, while the ignition loss of bottom ash decreased from 3% to 2%. The proposed method can reduce the measurement delay and systematic errors associated with traditional weighing-based metering, improve the refined operation and maintenance level as well as the power generation efficiency of municipal solid waste incineration projects, and provide reliable empirical data and control logic support for the application of intelligent combustion technologies.

In response to increasingly stringent emission standards and the demand for normal pollutant synergistic control in municipal solid waste incineration (MSWI), a large-scale waste-to-energy plant with a capacity of 5 200 t/d was taken as an research object. And the migration, transformation, and synergistic removal mechanisms of flue gas pollutants from the boiler outlet to the stack were systematically analyzed. Based on continuous emission monitoring data, the removal characteristics of particulate matter, SO2, HCl, and NOx were quantitatively evaluated, and the coordinated optimization path of acid removal process control, waste heat cascade utilization, and fly ash source reduction was explored. The results showed that the multi-stage coupled purification system could achieve high-efficiency synergistic removal of pollutants, with removal efficiencies of above 99.9%, above 99.0%, above 99.9% and 80.0% for particulate matter, SO2, HCl, and NOx, respectively, and emission concentrations were significantly lower than local ultra-low emission limits. The deacidification strategy of “mainly based on semi-dry method, with dry method regulation and wet method as the bottom line” could effectively reduce excessive Ca(OH)2 addition, maintaining the fly ash generation rate at around 2%. Furthermore, by constructing a cascade utilization system of flue gas waste heat coupled with GGH and SGH, the steam consumption of the SCR system was reduced by approximately 82.6%, corresponding to an electricity saving of approximately 0.044 kWh/m3 of flue gas. This study demonstrated that flue gas treatment in MSWI plants should shift from single-pollutant control to a coupled approach integrating multi-pollutant synergistic removal and energy efficiency optimization. The proposed system optimization strategy provides practical guidance for ultra-low emission retrofits of large-scale MSWI facilities.

With continuous acceleration of Shanghai’s urbanization process, the annual declared amount of construction waste has exceeded 100 million tons for two consecutive years. It means that the management of construction waste is facing arduous situation. To effectively address the challenges arising from the construction waste management process, the state and Shanghai have successively introduced many policies. However, we are still facing a series of challenges such as shrinkage of disposal space, increase of regulatory difficulties, and obstruction of resource utilization. The cost and benefit also needs to be further optimized. Therefore, under the goal of the “double carbon” and “zero-waste cities”, by analyzing the current situation of construction waste management in Shanghai, this paper pointed out the bottleneck benefits faced in the whole cycle management process from source generation to end disposal, and proposed that cost-benefit optimization should be taken as the core to solve the problem of construction waste governance. Furthermore, it proposed to build a management path for the whole chain optimization of “source reduction-intelligent supervision-resource utilization” for construction waste. This path aims to promote the transformation of construction waste management from “passive disposal” to “active value-addicition”, so as to achieve the dual dividends of environment and economy.

As the core hub of the waste collection and transportation network, the management efficiency of domestic waste transfer stations directly determines the economic costs, environmental performance and social acceptance of the urban domestic waste management system. To systematically summarize the full-process management experience of municipal solid waste transfer stations from planning and design to decommissioning and disposal, the life cycle management concept was introduced. Taking a large municipal solid waste transfer station in Jiangsu province as the research object, a systematic analysis was conducted on the full life cycle of the transfer station, and typical problems arising throughout the transfer station’s full life cycle were extracted and summarized. The results have been showed that planning and design is the researching stage for overall layout and process route, construction serves as a vital stage to turn design plans into physical projects, operation management is the core phase to ensure safe, environmentally-friendly and stable operation of facilities, while decommissioning and disposal represents the final stage for realizing the recycling and reuse of site resources. The countermeasures and suggestions proposed in this study are universally applicable, and can provide practical references for the life cycle management of similar urban domestic waste transfer stations.