Characteristics Of Municipal Solid Waste Research Articles

Analysis of physicochemical characteristics of municipal solid waste in Hung Yen city

Analysis of physicochemical characteristics of municipal solid waste in Hung Yen city

Influence of moisture content and inlet temperature on the incineration characteristics of municipal solid waste (MSW)

Incineration is an effective method for the treatment of municipal solid waste, pre-treatment reduces the waste moisture content to increase the incineration performance. However, the inlet temperature variation influenced by the environment is often ignored at this stage, and the coupling of moisture content and inlet temperature directly affects the incineration performance. To investigate the optimal inlet conditions for the incineration, the numerical model of a 600 t/d incinerator was established according to a reference case. Detailed analyses of the combustion characteristics of the bed and furnace is conducted under various moisture contents and inlet temperatures. The incineration efficiency under multiple factors is analyzed using response surface methodology, with sensitivity to these factors derived from the surface derivative. The results indicate that at an inlet temperature of 30 °C, the rates of volatile release and fixed carbon combustion are negatively correlated with the moisture content, and maximum incineration efficiency of 39.02 % is reached at a moisture content of 28.12 %. At a moisture content of 33.26 %, The rates of moisture evaporation, volatile release, and fixed carbon combustion are positively correlated with inlet temperature, and the maximum incineration efficiency of 38.76 % is achieved at an inlet temperature of 40 °C. The incineration efficiency exhibits a negative sensitivity to moisture content, whereas its sensitivity to inlet temperature is contingent upon the specific temperature range. The combination of 26.53 % moisture content and 40.86 °C inlet temperature yields the highest incineration efficiency of 40.69 %. The findings of this study provide useful information for the pre-treatment of municipal solid waste, contributing to the enhancement of operational efficiency in waste-to-energy plants.

Comprehensive Assessment and Optimization of a Middle-Arch Dual-Channel Municipal Solid Waste Incinerator Using Numerical Simulation Methods.

The present study focuses on a middle-arch dual-channel municipal solid waste (MSW) incinerator facing issues of high NO x emission and overheating. To address these problems and optimize the incinerator, an advanced numerical simulation method was employed to comprehensively assess its bed combustion, freeboard combustion, and NO x emission characteristics. A multiphase fuel bed model considering large-particle characteristics of MSW was developed, coupled with a three-dimensional (3D) model for combustion in freeboard. The analysis revealed that the observed issues stem from multiple factors, including primary-to-secondary air ratio, flame propagation in bed, release of volatiles from bed, and distribution and mixing of components in freeboard. Reducing the proportion of primary air and correspondingly increasing secondary air effectively alleviated the localized overheating in the furnace and reduced NO x emission. Further adjustments to the distribution of primary air in three stages delaying air supply toward the burnout stage, together with the decrease in the grate movement speed, can better control the amount and speciation of N released from the bed. Implementing a counterflow mixing strategy with NH3 in the front channel and NO in the rear channel can greatly reduce the original NO x emission concentration to 95.94 mg/(N·m3), as predicted by a numerical simulation. Subsequent practical adjustments to an actual incinerator led to notable improvements, clearly optimizing the localized high-temperature issues at various locations, especially the front channel suffering severe slagging problems, with the temperature reduced from 1118 to 957 °C. Meanwhile, NO x emission concentration decreased from 200 mg/(N·m3) to around 50 mg/(N·m3), with no negative effect on the boiler load.

Experimental evaluation of municipal solid waste air-gasification in a pilot-scale reciprocating moving-grate furnace

The increasing volume of municipal solid waste (MSW) worldwide presents significant environmental challenges, necessitating the development of efficient waste-to-energy (WtE) solutions. Among various thermochemical methods, gasification offers a promising approach for converting MSW into syngas, which can be utilized for energy generation. This study investigates the gasification characteristics of MSW in a pilot-scale reciprocating moving-grate furnace, focusing on the effect of key operating parameters such as equivalence ratio (ER), gasification temperature, and gasifying agent-staged ratio on gasification characteristics.Seven experimental schemes were tested with varying lower heating values (LHV) of MSW (ranging from 6.98 to 15.1 MJ/kg) and throughputs (ranging from 0.77 to 1.67 tons per day) to assess the adaptability and stability of the moving-grate system under different conditions. The results indicate that an ER between 0.6 and 0.7, a gasification temperature of 760 °C, and a gasifying agent-staged ratio of 7:3 are optimal for achieving a maximum energy conversion efficiency of 71.6 %. It was observed that the LHV of syngas decreases when the gasification temperature exceeds 850 °C due to increased oxidation of light hydrocarbons. Moreover, the study highlights the influence of grate moving speed on residence time and reaction completeness, which are critical for optimizing syngas yield and quality.The findings demonstrate that while the maximum energy conversion efficiency of the moving-grate system is lower than other reactor types, its lower capital and operating costs, due to the lack of dedicated feedstock pretreatment, make it a viable option for small-scale and pilot-scale applications. This study provides valuable insights into optimizing MSW gasification processes and underscores the potential of the moving-grate furnace for adaptable and cost-effective WtE applications. The novelty of this work lies in the comprehensive evaluation of the moving-grate gasification process under varied operating conditions, providing a foundation for future research on improving efficiency and reducing environmental impact in large-scale MSW management.

Evaluation of greenhouse gas emission and reduction potential of high-food-waste-content municipal solid waste landfills: A case study of a landfill in the east of China

This study proposes a comprehensive evaluation method based on a two-stage model to assess greenhouse gas (GHG) emissions and reductions in high-food-waste-content (HFWC) municipal solid waste (MSW) landfills. The proposed method considers typical processes such as fugitive landfill gas (LFG), LFG collection, flaring, power generation, and leachate treatment. A case study of an HFWC MSW landfill in eastern China is considered to illustrate the evaluation. The findings revealed that the GHG emissions equivalent of the case landfill amounted to 21.23 million tons from 2007 to 2022, averaging 1.03 tons CO2-eq per ton of MSW. There was a potential underestimation of LFG generation at the landfill site during the initial stages, which led to delayed LFG collection and substantial fugitive LFG emissions. Additionally, the time distribution of GHG emissions from HFWC MSW was significantly different from that of low-food-waste-content (LFWC) MSW landfills, with peak emissions occurring much earlier. Owing to the rapid degradation characteristics of HFWC MSW, the cumulative LFG production of the landfill by 2022 (2 years after the final cover) was projected to reach 77 % of the total LFG potential. In contrast, it would take until 2030 for LFWC MSW landfills to reach this level. Furthermore, various scenarios were analyzed, in which if the rapid LFG generation characteristics of HFWC MSW are known in advance, and relevant facilities are constructed ahead of time, the collection efficiency can be improved from 31 % to over 78 %, resulting in less GHG emissions.

Experimental Study on the Temperature-Dependent Static, Dynamic, and Post-Dynamic Mechanical Characteristics of Municipal Solid Waste.

Municipal solid waste (MSW) has huge potential to be recycled as construction material, which would have significant benefits for environmental conservation. However, the cornerstone of this undertaking is a solid comprehension of the mechanical response of MSW in real-world engineering locations, taking into account the effects of stress levels and temperature. In this paper, well-mixed MSW samples were sieved and crushed to produce standardized specimens in cylindrical molds. A series of static, dynamic, and post-cyclic shear tests were conducted on the MSW at temperatures ranging from 5 °C to 80 °C with normal stresses of 50 kPa, 100 kPa, and 150 kPa. The experimental findings demonstrate that the static, dynamic, and post-cyclic mechanical response of MSW presents temperature range-dependency; temperature variation between 5 °C and 20 °C affects MSW's mechanical reaction more than variation in temperature between 40 °C and 80 °C under various stress settings; at 5 °C~80 °C, the static peak shear strength of MSW is the highest, being followed by the post-cyclic peak shear strength, while the dynamic peak shear strength is the lowest; the sensitivity of the dynamic shear strength of MSW to temperature variation is the largest, being followed by the post-cyclic peak shear strength, and the static peak shear strength is the lowest.

Compressibility characteristics of municipal solid waste considering multiple factors.

Borehole samples were collected from a municipal solid waste (MSW) landfill in Xi'an, China, and subjected to a series of basic geotechnical and compression tests. This study aims to investigate the influence of composition, dry unit weight, moisture content, organic content, and landfill age on the compressibility of MSW. The results show that with increasing landfill age, the compressible components and organic content exhibit a decreasing trend while the dry unit weight increases. The moisture content does not vary significantly. There is also a linear trend between the logarithm of the primary compression strain and vertical stress. In addition, with an increase in compressible components content, moisture content, and organic content, the modified primary compression index (Cc') shows an increasing trend, whereas with an increase in dry unit weight and landfill age, Cc' shows a decreasing trend. Furthermore, regarding the 34 sets of data, authors only selected five data points for a detailed comparative analysis, this decision was made on the basis that these data points are representative. A modified primary compression index prediction model that considers the dry unit weight, moisture content, and landfill age of the MSW as influencing factors results in a fitting coefficient of 0.797. The Cc' values in this study are within the range of 0.12 to 0.36. These findings provide a reference for the vertical expansion design of existing landfills.

Estimation of calorific value using an artificial neural network based on stochastic ultimate analysis

The main aim of the present study was to estimate the calorific value (CV) by considering the uncertainty in municipal solid waste (MSW) generation using a cohesive Artificial Neural Network (ANN) technique. The parameters from ultimate analysis are taken as input data and CV as output data for 300 samples and seasonal variation is considered for predicting CV. Monte Carlo Simulation Technique is applied to deal with the uncertainty in MSW characteristics and the Simultaneous Backward Reduction (SBR) approach is used to tackle scenarios into a manageable number. Various ANN models were built based on the seasonal variation for three cities: ANNMS, ANNMW, ANNUS, ANNUW, ANNBS and ANNBW. The results depicted that network ANNMS for the architecture (9-21-1) has a minimum MAPE value of 1.22% with an estimation accuracy of 94.61%. The network ANNUS has a minimum MAPE of 1.62% has an estimation accuracy of 93.2% for the architecture (9-23-1). The network ANNBW Baddi City has a minimum MAPE is 2.23% for the network (9-21-1) with an estimation accuracy of 91.77% respectively. The developed ANNs model in the present study is beneficial to estimate the CV of MSW samples using elemental composition considering the uncertainty in the data, leading to more accuracy in the prediction models. It helps to minimize experimental costs and gives a theoretical background for modeling MSW's energy potential based on Waste to Energy (WTE) technologies.

Exergy Analysis of Waste-to-Energy Technologies for Municipal Solid Waste Management

In recent years, there have been increasing concerns over the detrimental effects of irreversible linear patterns of material and energy consumption, which have led to an enormous generation of municipal solid waste (MSW). Concepts like waste-to-energy (WtE) and recycling have gained increasing recognition and support as responses to these challenges. This study assessed the exergetic potential of four WtE technologies (landfill gas-to-energy, anaerobic digestion, incineration, and plasma gasification) in the context of the MSW characteristics of Maiduguri, Borno State. The population of Maiduguri, waste generation rate, waste composition, and the ultimate and proximate analysis of the MSW were used for the assessment. Exergetic potential in the form of electrical energy generation and three exergy-based indicators (exergy efficiency, exergy defect, and improvement potential) were evaluated for each WtE option. The results reveal that anaerobic digestion and plasma gasification are viable options based on the exergetic potential and the measured exergy performance indicators. These findings offer valuable insights for policymakers and waste management authorities, facilitating informed decisions to address environmental concerns and promote resource-efficient urban development in Maiduguri and similar regions.

A STUDY ON EFFICIENT MICROORGANISMS ISOLATED FOR DEGRADATION FROM MUNICIPAL SOLID WASTE OF CHHATRAPATI SAMBHAJINAGAR, MAHARASHTRA, INDIA

With rapid industrial development and the progress of civilization, the problem of increased waste generation has become more complex in urban areas. This research evaluates the composition and characteristics of municipal solid Waste produced in a representative residential neighbourhood. Ten samples were taken from the disposal site of the Chhatrapati—Sambhajinagar (Aurangabad) city area. Gathered from garbage, nine bacterial isolates were made using a nutrient agar medium. Investigations were conducted into the best culture conditions, microbiological traits, biochemical traits within the strains, tolerance to five heavy metals (Cadmium, zinc, Arsenic, lead and mercury), sensitivity to four different antibiotics (penicillin, streptomycin, oxytetracycline, and gentamycin), and extracellular enzyme production of the microbial strains. All six strains that could produce protease were used for the waste degradation efficiency test. Due to these findings, there is now a greater chance of identifying bacteria of scientific significance from municipal waste disposal sites, and these isolates may be a key source of compounds with practical applications in industry. Based on the research, it is possible to extract beneficial bacteria for the environmentally friendly bioconversion of solid Waste from the (Chhatrapati. Sambhajinagar (Aurangabad) city area.

Study on the pyrolysis and combustion characteristics of municipal solid waste in a fixed bed

Study on the pyrolysis and combustion characteristics of municipal solid waste in a fixed bed

Influence of main operating parameters on the incineration characteristics of municipal solid waste (MSW)

To study the influence of the main operating parameters on the incineration characteristics of municipal solid waste (MSW), a 375 t/d mechanical grate incinerator is selected as the research object, and the effects of primary air temperature, secondary air arrangement, and grate speed on the MSW incineration process are simulated, and experimental tests are carried out under different primary air temperature and grate speed conditions. The results show that the relative errors between the measured and simulated values of the incinerator outlet O2 content and the measurement point temperature are within ±5% for all test conditions. When the primary air temperature increases from 423 K to 503 K, the position where the MSW incineration ends moves 3.32 m towards the front of the grate, and the moisture evaporation and fixed carbon combustion rates also increase, but the maximum volatile release rate and the optimal incineration condition of the MSW occur at the primary air temperature of 483 K. The increase in grate speed delays the incineration process of MSW and decreases the moisture evaporation rate and fixed carbon combustion rate, but it worsens the incineration effect of MSW. When the grate speed increases from 6.94 m/h to 13.88 m/h, the MSW incineration process is delayed by 3.20 m, and the moisture evaporation and fixed carbon combustion rates decrease by 43 kg·m−2·h−1 and 9 kg·m−2·h−1, respectively. To achieve the optimal operating conditions, the secondary air volume ratio of the front and rear arches is 1.59:1, the secondary air direction of the front arch is 40° and 60°, and that of the rear arch is 0° for the primary air temperature of 463 K and 483 K, respectively. This study can provide useful insights for optimizing the design and operation of mechanical grate incinerators.

CFD–DEM Simulation of Heat Transfer and Reaction Characteristics of Pyrolysis Process of MSW Heated by High-Temperature Flue Gas

Pyrolysis is a promising disposal method for municipal solid waste (MSW) due to the high-value utilization of the organic components of MSW. Traditional indirect heating has low heat transfer efficiency and requires an increase in the heat exchange area. In this study, a refined numerical simulation model for the pyrolysis of four typical MSW components with high-temperature flue gas was established to study the influence of flue gas on the heat transfer and reaction characteristics of MSW. The temperature distribution and particle size change in different components were obtained, and the effects of flue gas temperature and velocity on the pyrolysis process were analyzed. It was found that the temperature difference of the four components along the bed height direction was about 1.36–1.81 K/mm, and the energy efficiency was about 55–61%. When the four components were uniformly mixed, the temperature increase rates of each component were similar during the pyrolysis process. As the flue gas temperature increased, the amount of gas consumption decreased and the energy efficiency increased. When the flue gas velocity increased, the flue gas consumption increased and the energy efficiency decreased. The research results are of great significance for the promotion and application of pyrolysis technology to MSW with high-temperature flue gas.

A review of existing methods for predicting leachate production from municipal solid waste landfills.

Landfilling is one of the predominant methods of municipal solid waste (MSW) disposal worldwide, while the generation of leachate, a kind of toxic wastewater, is among the primary factors behind landfill instability and environmental contamination problems. Precise prediction of leachate production is crucial to landfill safety evaluation and design. This paper presents a comprehensive review of methods for predicting leachate production from MSW landfills. Firstly, compositional characteristics of MSW and leachate generation mechanism are analysed. Factors influencing leachate production are summarised based on the generation mechanism, including the components of MSW, climatic conditions, landfill structure, and environmental factors. Then, we classified the existing methods for predicting leachate production into four categories: water balance formula, water balance model, empirical formula, and artificial intelligence model methods. Advantages, disadvantages, and applicability of different leachate production prediction methods are compared and analysed. Furthermore, limitations in the existing leachate production prediction methods for MSW landfills and scope for future research are discussed.

Long-term implications of municipal solid waste (MSW) classification on emissions of PCDD/Fs and other pollutants: Five-year field study in a full-scale MSW incinerator in southern China

Understanding how municipal solid waste (MSW) classification influences the physiochemical properties and incineration emission characteristics of MSW is imperative for sustainable waste management. To investigate how long-term changes in the composition and physical properties of MSW resulting from MSW classification affect the emissions of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and multiple flue gas pollutants, a five-year experiment (2018–2022) was conducted in a full-scale MSW incinerator in Shenzhen City, China. After MSW classification, the food waste in MSW was substantially reduced while the paper, textile, and wood components were notably increased. MSW classification also remarkably decreased the water and chlorine contents of MSW while concomitantly increasing the wet-based calorific value, sulfur content, and nitrogen content. Consequently, the PCDD/Fs emissions declined from 106.7 ng I-TEQ/t MSW in 2018 to 26.0 ng I-TEQ/t MSW in 2022. Moreover, a process-tracing experiment demonstrated noticeable decreases in PCDD/F synthesis in the post-combustion area, with mass-reduction efficiencies of 23.6 %–95.4 %. In a correlation analysis, the PCDD/F emissions were significantly positively correlated with food waste, water content, and chlorine and negatively correlated with the wet-based calorific value and nitrogen content. Furthermore, MSW classification reduced the emissions of conventional flue gas pollutants (SO2, CO, and HCl) and multiple heavy metals (total sum of Sb, As, Pb, Cr, Co, Cu, Mn, and Ni). In summary, the long-term study demonstrated that MSW classification can feasibly separate incombustible waste, improve combustion quality, and reduce pollutant emissions from sources. These findings offer practical guidance for promoting MSW classification.

Study on the Co-gasification characteristics of biomass and municipal solid waste based on machine learning

Co-gasification of biomass and municipal solid waste (MSW) exhibits synergistic effects by improving the quality of syngas while reducing environmental pollution from MSW. In this study, Machine learning (ML) techniques were employed to investigate the co-gasification process of biomass and MSW. A comprehensive dataset was constructed using existing data, including different feedstock types and operating conditions, with 18 input features and 9 output features. Four advanced ML models were utilized to model and analyze the co-gasification process. By leveraging feedstock characteristics and operating parameters, key gasification parameters such as syngas composition, lower heating value (LHV) of syngas, tar yield, and carbon conversion efficiency were predicted. The results showed that all four models exhibited excellent predictive performance, with R2 values greater than 0.9 in both the training and testing stage. Specifically, Histogram-based gradient boosting regression (HGBR) exhibited the lowest root mean square error (RMSE) in predicting CO, while the gradient boosting regressor (GBR) achieved the best performance in H2 prediction with a RMSE of 1.6. The most influential input features for CO concentration were equivalence ratio (ER), oxygen content in biomass and hydrogen content in biomass. The key features affecting H2 concentration were steam/fuel and ER.

Online Combustion Status Recognition of Municipal Solid Waste Incineration Process Using DFC Based on Convolutional Multi-Layer Feature Fusion

The prevailing method for handling municipal solid waste (MSW) is incineration, a critical process that demands safe, stable, and eco-conscious operation. While grate-typed furnaces offer operational flexibility, they often generate pollution during unstable operating conditions. Moreover, fluctuations in the physical and chemical characteristics of MSW contribute to variable combustion statuses, accelerating internal furnace wear and ash accumulation. Tackling the challenges of pollution, wear, and efficiency in the MSW incineration (MSWI) process necessitates the automatic online recognition of combustion status. This article introduces a novel online recognition method using deep forest classification (DFC) based on convolutional multi-layer feature fusion. The method entails several key steps: initial collection and analysis of flame image modeling data and construction of an offline model utilizing LeNet-5 and DFC. Here, LeNet-5 trains to extract deep features from flame images, while an adaptive selection fusion method on multi-layer features selects the most effective fused deep features. Subsequently, these fused deep features feed into DFC, constructing an offline recognition model for identifying combustion status. Finally, embedding this recognition system into an existing MSWI process data monitoring system enables online flame video recognition. Experimental results show remarkable accuracies: 93.80% and 95.08% for left and right grate furnace offline samples, respectively. When implemented in an online flame video recognition platform, it aptly meets recognition demands.

Characterising and Analysing the Composition and Characteristics of Municipal Solid Waste (MSW) in Delhi, India

This research presents a comprehensive analysis of municipal solid waste (MSW) composition and characteristics from four landfill sites in Delhi, India. The study reveals that the moisture content in the MSW from all sites was below 40%, impacting leachate formation and microbial activities. Varied compositions were observed among the sites, with the Okhla landfill having higher paper and plastic content, while the Ghazipur landfill exhibited elevated wood content. Recycling emerges as a crucial focus, with approximately 36.5% of the waste comprising reusable materials like plastic and paper. Composting, particularly vermicomposting, proves to be a promising waste disposal method due to the substantial organic content (approximately 75%) in the MSW. These findings hold significant implications for waste management policies in Delhi, encouraging sustainable practices and effective waste treatment strategies for a greener future.

Characteristics of Municipal Solid Waste in Some Urban Agglomeration in the Past Five Years

The treatment and disposal of municipal solid waste has increasingly become a common concern around the world, and the characteristics of municipal solid waste(MSW) are an important basis for the selection of terminal treatment methods. In this study, more than 400 MSW samples from over 30 cities across China were collected, and the basic physical and chemical properties, such as the physical composition, pollutant content, and calorific value, were analyzed. Shenzhen was taken as an example to analyze the influence of time and waste sorting measures on the physical and chemical characteristics of MSW. The correlation model between MSW composition and calorific value was established using partial least squares(PLS) regression, and the model was verified. The results showed that with per capita GDP increasing by 10,000 yuan, per capita MSW production and the low calorific value of MSW increased by 0.1 kg·(person·d)-1 and 373.8 kJ·kg-1, respectively. However, when per capita GDP was less than 60,000 yuan, the correlation between per capita GDP and per capita MSW production was relatively poor. Kitchen waste was still the most abundant component of MSW, and the content of most samples was between 40% and 60%. The combustible content of rubber/plastic and paper was relatively high, between 20%-30% and 10%-20%, respectively. The inorganic content did not usually exceed 5%, and the moisture content of the MSW was between 50% and 60%. After the implementation of waste classification in 2019, the content of kitchen waste in MSW had been significantly reduced, the content of rubber/plastic had increased, and other components had not changed much. Additionally, the calorific value of waste had been improved to a certain extent. The pollution element contents in MSW, S Cl, and N were all below 1%, and the average value was:N>Cl>S. The contents of Hg, As, Cr, Cd, and Pb in MSW samples did not change significantly with the composition and sampling time, and the content of Pb and Cr in MSW was affected by the environmental background value. The model analysis revealed that rubber/plastics and moisture content were the main variables that affected the calorific value of MSW. The deviation between the measured value and the predicted value was less than 20% for 85.96% of the samples. The model established in this study can meet the needs of the prediction of the calorific value of MSW.

Emission characteristics of typical gas pollutants during oxygen-enriched waste incineration process

Oxygen-enriched waste incineration can improve incineration efficiency and reduce pollutant generation, while greenhouse gases and pollutant emission characteristics of different wastes are still unclear. In this study, pollutant emission characteristics of actual municipal solid waste (MSW) and typical components at different oxygen concentrations and moisture content were investigated to reveal the pollutant generation mechanism. The results illustrated that when oxygen concentrations increased from 21% to 30%, CO, CH4 and HCN emissions decreased by 95%, 95.5% and 96.5%, respectively. NO emissions increased by 75% due to the promotion of oxygen on fuel NO and rapid NO. The slight increase in SO2 (from 25.8% to 26.87%) was due to the promotion of oxygen on organic S and the reaction between SO42− and HCl. The decrease in HCl emissions (from 78.42% to 76.85%) was caused by the increasing deacon reaction. Besides, with increasing moisture content, CO, CH4 and HCN generation decreased first because of the CO oxidation and CH4 reforming reaction, and then increased due to the water–gas reaction between fixed carbon and water. Furthermore, the moisture content contained (66%) would promote NO and HCl generation by 35.7% and 9.1% through fuel N oxidation by OH radicals and hydrolysis of chlorine salt at high temperatures. The increased oxygen concentration would inhibit the moisture influence and improve applicability for different MSW. In addition, 25% oxygen-enriched incineration was selected as the most suitable parameter for improving combustion efficiency and reducing pollutant emissions of MSW with high moisture content.