Properties Of Municipal Solid Waste Research Articles

Characterization of Long‐Term Municipal Solid Waste Constitutive Behavior With Coupled Biodegradation and Fibrous Reinforcing Effects

ABSTRACTTo appropriately simulate the long‐term mechanical behavior of municipal solid waste (MSW), a constitutive model coupling the effects of biodegradation and fibrous reinforcement was developed. In the proposed model, the compressive deformation due to biodegradation was regarded as being caused by an additional equivalent stress. Considering the effect of biodegradation, an evolution equation of the equivalent stress was proposed, and a plastic volumetric strain hardening law was developed. A fibrous reinforcement parameter was introduced, which was associated with the fiber content, stress state, and plastic shear strain of MSW. A plastic shear strain hardening law was developed to model the fibrous reinforcement. Based on the associated flow rule and two plastic strain hardening laws, the proposed model was established. The proposed model well simulated the hardening properties of MSW, as evidenced by the stress‒strain curves and the consistent, nonlinear increase in volumetric strain with axial strain. The differences in the shear strength and volumetric deformation due to the confining stress and fiber content were also well simulated by the model. Furthermore, the model predictions accurately reflected the findings of experiments conducted over a period of 10 years. Finally, parametric investigations were used to calibrate this proposed model, which can well characterize the long‐term MSW mechanical behavior.

Analyzing the impact of age on waste properties at an open dumpsite in Khulna

The rapid growth of the population has led to a significant increase in the amount of municipal solid waste (MSW), posing a burden and concern for our environment. Landfill mining as well as waste to energy could be a solution to this issue, but they require waste composition, particle size, and physiochemical and ultimate analysis are prerequisite requirements. Particle size was assessed through sieve analysis, categorizing MSW into ten different types followed by physiochemical and ultimate analyses. This study aimed to examine how the properties of MSW change with age. Findings showed that fine particles increased with age while larger particles decreased. With aging, certain physical components decreased, while others either increased or stayed constant. Organic content showed a significant decrease of 70.548% for fresh MSW and 0.35% for fifteen-year-old waste whereas plastic content remained almost constant after an increase from fresh MSW. Moisture content and volatile content of MSW reduced with age while fixed carbon and ash content increased with age. Ultimate analysis shows a drop of carbon, hydrogen, and nitrogen while oxygen shows a rise. Calorific value was found a decrease in trend with age indicating that the energy content of MSW reduced with age. A drastic reduction of unit weight was found in this study, dropping from 9.31 KN/m3 to 4.668 KN/m3. This study highlights the overall composition of MSW, the fluctuation in physiochemical analysis with age, and the sieve analysis and particle size distribution. It also displays the unit weight and the age-wise variation of the ultimate analysis. The findings of this study will aid landfill mining and waste to energy by providing comprehensive properties of MSW.

An innovative approach to municipal solid waste characterization for waste-to-energy processes in Egypt

This study enhances municipal solid waste (MSW) characterization methodologies by introducing an innovative sampling approach that prioritizes organic content over traditional components like paper and cartons, particularly suited to developing countries like Egypt. This innovative method adapts the ASTM D5231 − 92 standard to capture the actual MSW profile in the Giza governorate, where this research was carried out. Focusing on organic waste, this approach ensures more relevant and accurate data for waste-to-energy (WtE) conversion processes. This research documents significant seasonal variability in waste composition, with organic content averaging 66 % in winter compared to 59 % in fall. The energy-rich fraction shows similar variability, with winter having an average of 28 % compared to fall's 30 %. Moreover, the calorific value is notably higher in winter at 10.3 MJ/kg, compared to 8.4 MJ/kg in fall. These variations are critical for optimizing energy recovery processes in WtE projects. The results from this case study contribute to the limited but growing body of knowledge on waste management in Egypt, demonstrating the feasibility and benefits of adapting standard characterization methods to local conditions. The insights gained from this research fill a notable gap in the regional waste management literature and enhance the scientific understanding of how seasonal factors affect MSW properties, providing a robust framework for improving waste management practices in similar settings globally.

In-situ and Laboratory Geotechnical Properties of Municipal Solid Waste from South Eastern Johannesburg

In-situ and Laboratory Geotechnical Properties of Municipal Solid Waste from South Eastern Johannesburg

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.

Assessment Some of The Geotechnical Properties of Municipal Solid Waste at Soran Waste Dumping Site, Kurdistan Region of Iraq

Assessment Some of The Geotechnical Properties of Municipal Solid Waste at Soran Waste Dumping Site, Kurdistan Region of Iraq

Experimental investigation of biochemical and geotechnical properties of municipal solid waste undergoing biodegradation for landfill design

Experimental investigation of biochemical and geotechnical properties of municipal solid waste undergoing biodegradation for landfill design

An elastoplastic constitutive model for municipal solid waste (MSW) incorporating solid particle compression and fibrous reinforcing effect

The failures in municipal solid waste (MSW) landfills could result in considerable ecological as well as social problems. Numerical simulations are widely employed to analyze MSW deformation and stability. These methods require an appropriate stress-strain characterization of MSW, which is crucial. Different from soils, the extremely complicated constituents of MSW contain a large number of fibrous reinforced and particle compressible materials. The findings of numerous tests suggest that the fiber reinforced phase and the basic phase are solely responsible for determining the mechanical properties of MSW. On the basis of the double-phase assumption, a new plastic potential function of MSW is developed considering that the reinforcement of fibrous materials only relates to plastic shear strain and the particle compression only affects plastic volumetric strain. According to the associate flow rule, a constitutive model based on elastoplasticity is developed for MSW. The strain hardening behaviour of MSW is well predicted by the model, and this behaviour is in good agreement with experimental evidence. Effects of confining pressure and fibre content are modelled, together with the mechanical and deformation behaviour of MSW. The accurate calculation of effective stresses is obtained through considering the MSW particle compression under the undrained conditions. Parametric investigations calibrate the model and show its properties by comparing them to data from triaxial tests. Moreover, incorporating the proposed model, finite-element numerical simulation was conducted, and the results of finite-element numerical simulation were compared with field monitoring results.

Assessment of The Geotechnical Properties of Municipal Solid Waste and Its Effect on The Surrounding Soil: A Review

Due to rapid growing of population and active lifestyle, massive amounts of municipal solid waste (MSW) are produced worldwide. The MSW can harm the environment and threaten the land if the dumping sites are not managed scientifically. The geotechnical properties of MSW are the key parameters required in the landfill operations and waste management facilities. Hence, presence of the geotechnical properties data of the waste can assist engineers in selecting possible solutions for extension of the landfill and obtaining prior background data for the evaluation and design of landfills. MSW disposal changes the geotechnical properties of soil. Also, alterations in the geotechnical properties of soils may contribute to the physical and physico-chemical interactions between soil and contaminants of the dumping sites. As leachate, which is generated by the waste, penetrates into the soil, it moves pollutants into the soil and influences the strength and stability of the soil. The main objective of this research is to summarize the most recent literature of the physical and mechanical properties of MSW, and their influence on the geotechnical properties of soil. The findings of numerous investigations on the physical and mechanical characteristics of MSW and soil influenced by MSW are presented and discussed. Depending on the reviewed research studies, it can be observed that the engineering characteristics of MSW are complicated and varied for various reasons. The waste components and degradation process can cause an increase in moisture content and unit weight, and a decrease in organic content, hydraulic conductivity and compressibility of MSW. Additionally, MSW sites significantly impact the physical and mechanical characteristics of underlain and surrounding soil and deteriorate the soil quality. Further, it was noticed that the influence of dumping on soil is reduced with depth due to less interaction between the soil and waste

The impact of pollutant emissions from co-incineration of industrial waste in municipal solid waste incinerators

A large amount of industrial solid waste (including waste plastics, textiles, wood, etc., which are byproducts of industrial production) urgently needs to be treated. Incineration is undoubtedly the most efficient and convenient method. The existing municipal solid waste incineration plants can be transformed to burn such industrial wastes. However, the potential risks associated with high levels of heavy metals in industrial waste and the air pollution caused by co-incineration pose significant challenges to the co-incineration disposal of industrial solid waste. The change of physical and chemical properties of municipal solid waste and the emission characteristics of flue gas pollutants after co-incineration of industrial waste were studied by means of material flow simulation and experiment. In addition, experiments were designed to study the effects of temperature, calcium sulfur ratio and chlorine content on heavy metal emission during the incineration of industrial waste. The results showed that co-incineration of a certain proportion of industrial waste significantly increased the calorific value of municipal solid waste, but excessive mixing of plastic and paper industrial waste would increase the ash content. Co-incineration of plastic industrial waste can significantly increase HCl, and with the increase of temperature, the transformation of Cl to HCl is more thorough. The increase of temperature can promote the migration of Cr, Pb and Se elements to the gas phase. When Cr, Pb, and Se elements are present in the gas phase, they can combine with other gases and aerosols to form particulate matter and toxic substances, causing air pollution. When Ca/S is 1, Ba, Mn, Ni, Zn can effectively reduce the retention rate of elements in the ash. Under certain conditions, chlorine in industrial waste plastics will react with Zn to form tiny particles and low boiling point chlorides, which will increase its volatility. The mineral components in the ash can also be used for making ceramsite and building materials. These results will provide reference for the pollutants controlling during co-incineration of industrial waste and municipal solid waste process.

Effect of Material Composition on Geotechnical Properties—Study on Synthetic Municipal Solid Waste

The geotechnical properties of municipal solid waste (MSW) are required to design and maintain a landfill structure. Several landfill failures occurring in recent times have led to the loss of revenue and people. This study aims to investigate the impact of material composition on the geotechnical properties of fresh synthetic municipal solid waste (SMSW), which imitates the real waste produced in India. The study aims to understand the contribution of each material, such as paper, plastic, and organic matter, on the shear behavior of SMSW, which is essential for designing landfills and ensuring their safety and performance. A modified proctor test and a large-scale direct shear test were used to determine the unit weight and shear strength of SMSW, respectively. The synthetic waste’s unit weight and shear strength were found to be consistent with values that had already been published. The shear strength parameters of SMSW include cohesion, which was determined to be at the lower bound of the envelope, and friction angle within the envelope. Lower unit weight, less fine soil-like material, and dry material are thought to be the causes of the observed variation in the behavior of actual waste in synthetic waste. The findings of this experiment demonstrated that as the proportion of paper increases, the cohesion (C) increases, and the friction angle (Φ) decreases. Cohesion and friction angle both decrease as the proportion of plastic increases. Cohesion and friction angle both increase with an increase in the organic percentage. These findings demonstrate that each material contributes differently to the shear behavior of SMSW. Hence, the material composition’s effect should be considered while designing a landfill for improved safety and reliability.

The Thermochemical Conversion of Municipal Solid Waste by Torrefaction Process

In this work, the thermochemical properties of municipal solid waste (MSW) are studied using the torrefaction process as the main method for investigation. Torrefaction experiments were carried out using an electric laboratory furnace, at temperatures of 200, 250, and 300 °C. The residence time was set to 90 min. Proximate and ultimate analysis were performed on the torrefied MSW samples and compared with the properties of the raw MSW samples. In addition, the thermal properties of the obtained torrefied MSW samples were evaluated by thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). The following could be stated: the obtained results showed that mass and energy yields (MY and EY, respectively) decrease with increasing when torrefaction temperature, while the heating values (HHV) increased under the same conditions (from 24.3 to 25.1 MJ/kg). Elemental analysis showed an increase in carbon content (C), from 45.7 ± 0.9 to 52.8 ± 1.05 wt.%, and decrease in oxygen content (O), from 45.6 ± 0.9 to 39.5 ± 0.8 wt.%, when torrefaction temperature is increased, which is consistent with the general definition of the torrefaction process. In addition, enhancement factors (EFs) and fuel ratios (FRs) were calculated, which ranged from 1.00 to 1.02 and 0.16 to 0.23, respectively. Some anomalies were observed during the thermal analysis, which are assumed to be related to the composition of the selected MSW. This study therefore shows that torrefaction pretreatment can improve the physicochemical properties of raw MSW to a level comparable to coal, and could contribute to a better understanding of the conversion of MSW into a valuable, solid biofuel.

Shear Strength Characteristics of Municipal Solid Waste

Disposal of Municipal Solid Waste (MSW) has become a serious problem all over the world which is affected by the rising population and rapid urbanization. Most of the developed countries tend to proceed with engineered landfilling or incineration of solid waste while developing countries continue with open dumping. Most of these open dump sites are located on marshy lands or low lying land areas due to the high demand for prime lands in city areas, and they are expanded in vertical direction, saving the horizontal spaces. Therefore, physical, chemical and shear strength properties of MSW are timely important to overcome the stability failures of the dump sites during the operational period and after the closure of the dump sites. In this study, engineering properties of MSW were investigated using several laboratory experiments for disturbed waste samples collected from Meethotamulla dump site. In order to represent the aging effect of MSW, samples were extracted at different depths and variation of geotechnical properties with aging was analysed. Based on the laboratory test results, it can be noted that MSW in open dump sites in wet zone of Sri Lanka mainly consists of fine residue, aggregated soil, polythene and textiles. Further, higher shear strength parameters were obtained for MSW due to presence of textiles within the waste body. As such, it can be concluded that, it is necessary to consider the influence of textiles in analyzing the stability of open dump sites.

Effects of moisture content and landfill age on the shear strength properties of municipal solid waste in Xi'an, China.

With the continued expansion of waste landfills, accidents may occur if the landfills are not properly stabilized. In this study, samples of municipal solid waste (MSW) from a waste landfill in Xi'an, China were collected through on-site drilling. Considering the effects of nine landfill ages (1, 2, 3, 11, 12, 13, 21, 22, and 23 y) and six moisture contents (natural, 20, 40, 60, 80, and 100%), 324 groups of MSW were tested in the laboratory using a direct shear test apparatus. The results indicate the following: (1) with an increase in horizontal shear displacement, the shear stress of MSW gradually increases without a peak stress phenomenon, which is a displacement hardening curve; (2) with an increase in landfill age, the shear strength of MSW increases; (3) with an increase in moisture content, the shear strength of MSW increases; (4) with an increase in landfill age, the cohesion (c) decreases and the internal friction angle (φ) increases; and (5) with an increase in moisture content, the c and φ of MSW increases. The c range found in this study was 6.04-18.69kPa, while the φ was 10.78-18.26°. The results of this study can provide a reference for stability calculations for MSW landfills.

Global void ratio of municipal solid waste for compression indices estimation.

Compressibility is one of the important engineering properties of municipal solid waste (MSW) affecting the stability and functionality of a landfill. Although the correlations between MSW properties and compression parameters have been established, they either have low accuracy and small datasets or are only limited to a few specific landfills in a region. In this study, a new method using the initial global void ratio (e0*) of MSW to estimate the compression indices is developed based on a comprehensive MSW dataset. The dataset consists of 124 sets (91 laboratory and 33 field) of MSW compression results obtained from 44 studies in 13 countries with different income levels and climate conditions. We categorized MSW as a ternary mixture with biodegradable (B), reinforcing (R), and inert (I) fractions, and suggested average specific gravity values (Gs,B=1.20, Gs,R=1.07, and Gs,I=2.64), respectively. The e0* values were calculated using the initial dry unit weight (γd,0) and ternary composition of MSW. The correlations between the e0* and the immediate compression index, secondary compression index induced by mechanical creep, and secondary compression index induced by bio-compression of MSW were evidently established. The results are applicable to the MSW with B=0-79.2%, R=0-54.0%, I=2.8-100.0%, and γd,0=2.0-14.2 kN/m3. A simple flowchart was established to estimate the compression indices and strains of MSW disposed on in landfills and dumpsites in countries with different income levels.

Constitutive model for stress–Strain responses of municipal solid waste considering fibrous reinforcement

The triaxial test results of municipal solid waste (MSW) with different fibrous content show that reinforcement of fibrous materials is the key factor affecting the mechanical properties of MSW. Thus, MSW is regarded as a composite of fibrous materials (plastic +textiles) and paste (i.e., any other non-fibrous materials). Under load, its mechanical behavior is determined by the two materials listed previously. This study introduces the notion of fibrous-reinforced parameters and provides the corresponding evaluation equation. A new plastic potential function reflecting the reinforcement effect of fibrous materials is developed to establish the elastoplastic constitutive model for predicting stress–strain responses of MSW. Comparing anticipated and experimental findings of various MSW demonstrates that the suggested constitutive model’s predictions are in good accordance with the test data. This model reproduces the essential aspects of the upward curving of the stress–strain curves and continuous volumetric strain increase with axial strain more precisely during loading, particularly for the upward curve form at a higher strain level. Meanwhile, the model is also able to capture the characterization of larger volumetric strains for MSW specimens with a higher fibrous content and larger volumetric strain for lower confining stress. Comparing the measured data and model parameter analysis reveals that the suggested model can accurately mimic the mechanical and deformation properties of MSW, hence providing a theoretical foundation for the landfill project.

Influence of heterogeneity and elevated temperatures on the seismic translational stability of engineered landfills

This paper proposes a new generalised closed-form solution to estimate the safety factors for translational failure of landfills considering the effects of heterogeneity and temperature variation with the depth of the landfill. The influence of heterogeneity was considered in the form of a shear wave velocity profile, while the influence of temperature was accounted for by considering the temperature-dependent shear strength properties. The proposed method also considered the influence of material damping and the mode change behaviour of the landfill. The safety factor for translational failure of the landfill was estimated using the limit equilibrium-based two-part wedge method. The proposed method was validated by comparing the safety factor obtained from this method with comparable analytical solutions. An extensive parametric study was conducted to demonstrate the influences of the landfill geometry, shear strength properties of municipal solid waste and liner components, parameters of strong ground motion, heterogeneity, and landfill temperature on the calculation of safety factors. The interfacial shear strength properties of liner components played a vital role in the translational stability of landfills compared to the shear strength properties of municipal solid waste. The frequency of base excitation showed a strong influence on landfill stability, while the material damping displayed a nominal effect. For the cases considered in this study, when the frequency of base excitation was close to the fundamental frequency of the landfill, the base acceleration was amplified by 6.7 times which reduced the safety factor by approximately 1.6 times. Heterogeneity and temperature have a significant influence on landfill stability. The increased degree of heterogeneity caused an approximately 27% reduction in the safety factor. For the given set of input parameters, the elevated temperature in the landfill alone decreased the safety factor by a maximum of 18%, while it reduced by approximately 60% under the combined influence of seismic, heterogeneity, and elevated temperature.

Controlling reactions during heavy metal leaching from municipal solid waste incineration fly ash

This research aimed to characterize the physical and chemical properties of municipal solid waste (MSW) incineration fly ash, as well as to investigate the leaching of heavy metals during toxicity characteristics leaching procedure (TCLP) process. To understand the leaching behaviour, concentrations of heavy metals, chloride, sulphate and calcium at various leaching, time was monitored together with pH of the leaching solution. Results showed that the chemical compositions of fly ashes led to differences in leaching environment. For the two fly ashes under study, one resulted in a leaching environment with pH of 10?12 while the other had pH about 6?7. Based on pH, anions and cations concentrations, Minteq software was employed to investigate the speciation of heavy metals. Results showed that the shift in precipitation/dissolution balance of carbonate and hydroxides of heavy metals could explain the fluctuation in metal concentrations during the leaching process, which indicates that leaching was probably controlled by these reactions. On the other hand, addition of EDTA changed the controlling reactions. Chelating reactions between heavy metals and EDTA led to much higher leaching toxicity due to the presence of heavy metals, showing that the presence of chelating organics in natural environment may facilitate heavy metal leaching.

Microbial community profiling in bio-stimulated municipal solid waste for effective removal of organic pollutants containing endocrine disrupting chemicals

The study was aimed to improve the degradation of organic pollutants in municipal solid waste (MSW) through the bio-stimulation process. The results showed that the physico-chemical properties of MSW (control) had a high value of pH (9.2 ± 0.02); total suspended solids (TSS: 1547 ± 23 mg/kg−1), and total dissolved solids (TDS:76 ± 0.67 mg/kg−1). After the biostimulation process (biostimulated MSW), the physico-chemical parameters of MSW were reduced as pH (7.1 ± 0.01); TSS (41 ± 0.01 mg/kg−1), and TDS (789 ± 03 mg/kg−1). Furthermore, the major organic pollutants detected from MSW by gas chromatography-mass spectroscopy (GC-MS) analysis at different retention time (RT) were hexadecane (RT-8.79); pentadecane (RT-9.36); and hexasiloxane (RT-9.43) while these organic pollutants were degraded after the biostimulation process. The whole-genome metagenome sequencing size (%) analyses showed major groups of bacteria (40.82%) followed by fungi (0.05%), virus (0.0032%), and archaea (0.0442%) in MSW. The species richness and evenness of the microbial community were decreased substantially due to the biostimulation treatment. The total number of genes in the biostimulated MSW (PS-3_11267) sample were 465302 whereas the number of genes in the control MSW (PS-4_11268) sample were 256807. Furthermore, the biostimulated MSW (PS-3_11267) aligned the reads to bacteria (19502525), fungi (40030), virus (3339), and archaea (12759) genomes whereas the control sample (PS-4_11268) aligned the reads to bacteria (17057259), fungi (19148), virus (1335), and archaea (18447) genomes. Moreover, the relative abundance at genus level in biostimulated MSW (PS-3_11267) (Ochrobactrum and Phenylobacterium), phylum; (Proteobacteria and Actinobacteria), and species (Chthoniobacter flavus and Vulgatibacter incomptus) level was the most abundant. The results provided valuable information regarding the degradation of organic pollutants in MSW by microbial communities through biostimulation for the prevention of soil pollution and health protection.

A component synergy of flue gas torrefaction of municipal solid waste

Flue gas torrefaction (FGT) is a promising pretreatment to improve the fuel properties of municipal solid waste (MSW). A synergistic effect between paper, wood and PVC was studied in flue gas and nitrogen torrefaction atmospheres. FGT presented superior potential in improving fuel properties compared to nitrogen torrefaction (NT). Notably, the synergistic effect between different ingredients in FGT could reduce mass and energy losses effectively, especially the combination of PVC with other materials. Besides, the FGT samples exhibited better thermal stability than NT samples during pyrolysis and combustion. Simultaneously, FGT led to the released flammable gases (H2 and CO) increase, while H2O decrease. Satisfyingly, less gaseous pollutants were released during the FGT samples combustion, attributed to the reduction of light volatiles and the enrichment of char and heavy volatiles. Moreover, the positive synergistic effects of FGT or NT blended samples were found in the pyrolysis (in phase B: ∆WNT-DTG = 4.79–5.20 and ∆WFGT-DTG = 0.78–1.18) and combustion (in phase B: ∆WNT-DTG = 6.03–16.07 and ∆WFGT-DTG = 1.56–13.4). This study can provide a theoretical reference for the efficient and clean treatment of MSW.