Municipal Solid Waste Research Articles

Segregation of Municipal Solid Waste Based on Their Biodegradability Using Spectroscopy Sensor

Segregation of Municipal Solid Waste Based on Their Biodegradability Using Spectroscopy Sensor

Valorization of Date Molasses and Municipal Solid Waste for the Production of Cellulases by Trichoderma reesei Al-K1 149 in a Tray Reactor

Valorization of Date Molasses and Municipal Solid Waste for the Production of Cellulases by Trichoderma reesei Al-K1 149 in a Tray Reactor

A comparison on the critical success factors of MSW and RDF power plant development in Thailand: Using an interpretive structural modelling and cross-impact matrix multiplication applied to classification analysis

Waste-to-energy (WtE) power plants, supplied mainly with municipal solid waste (MSW) and refuse-derived fuel (RDF), which convert waste into electricity, have emerged as a solution to Thailand's waste management problems. This study focused on identifying and studying the critical success factors (CSFs) that influence the success of MSW and RDF power plants in Thailand. This study employed interpretive structural Modelling and cross-impact matrix multiplication applied to a classification analysis to evaluate the impact of these CSFs on the development of WtE projects. The results showed that, for MSW, most CSFs were related to energy and waste management policies, followed by waste quality for electricity generation. In addition, strong financial resources and appropriate power plant locations are important for MSW management success. Conversely, for RDF, most CSFs were sufficient waste quality for electricity generation and performed well according to licensing conditions. In this study, high-level CSFs indicated that these factors were crucial for MSW and RDF development. CSFs differ based on specific technologies and regulations. However, sufficient waste quality (heating value and moisture content) is a common CSF in the MSW and RDF technologies. This study provides valuable insights into the CSFs that affect the development of WtE. Understanding and addressing these CSFs is essential for the development and operation of WtE power plants in Thailand and other countries with similar conditions. Thus, policy-makers and other stakeholders can make informed decisions to ensure the success of WtE projects.

Численное моделирование миграции фильтрационных вод от объектов размещения твердых коммунальных отходов через грунтовые защитные сооружения

The paper studies numerically he processes of pollutant migration from the municipal solid waste (MSW) landfill and discusses the obtained results. Pollution of the natural environment with residues of substances and products resulting from the human household and industrial activities is one of the most urgent problems both in Russia and all over the world. In economically developed countries, in which waste management strategies are implemented to minimize garbage accumulation, priority is given to neutralization and recycling technologies, The beneficial effect of such strategy is a significant reduction of the waste volume. In Russia, despite the positive dynamics in the use of new waste management technologies, the main method of their treatment is disposal at MSW landfills. On the territory of Russia, along with the MSW landfills operated and built in accordance with environmental requirements, there are a large number of unauthorized landfills, which are of serious hazard to the environment. This raises the question of assessing the impact of such facilities on the environment. To study the characteristics of the pollutant distribution and determine the waste migration parameters, the archival data from a set of field and laboratory studies in the area of the existing MSW disposal site were used. A numerical model was constructed to describe the hydrodynamics of the migration of substances in the soil and soil layer forming the base of a solid waste disposal facility. The process of pollutant spreading is described in terms of dry residue. The model takes into account such factors as convective transport, diffusion and geological composition of the base of the waste disposal site, which have a significant impact on the pollutant migration.

Maximizing Waste-to-Energy Potential: Optimizing Batch Torrefaction Reactor of Refused-Derived Fuel for Efficient Gasification

Abstract Refuse-derived fuel (RDF) from municipal solid waste (MSW) is a promising alternative to fossil fuels, but its varied composition can impede direct gasification. This industrial research project conducted a series of batch experiments to assess four key parameters: energy yield, mass yield, energy density, and combustion characteristics in the context of RDF torrefaction. The batch reactor processed RDF samples at temperatures of 250°C, 300°C, and 350°C, each with a 30- minute residence time under an inert atmosphere. In addition, Combustion TGA experiments, involving heating torrefied RDF up to 1000°C at a rate of 20°C/min, provided further insights into the robust combustion properties of the torrefied material. Unlocking the secrets of torrefaction magic, we've achieved remarkable energy content boosts. Torrefaction at 250°C, 300°C, and 350°C led to energy content enhancements of 22%, 29%, and 37%, respectively, compared to the original RDF. Notably, the most favorable energy yield was achieved during torrefaction at 250°C, attributed to both its relatively high energy content and mass yield. At a torrefaction temperature of 250 °C and above, the torrefied RDF samples exhibited heating values comparable to standard coal ranges between 25-35 MJ/kg. It is suggested that torrefaction of RDF is an effective pre-treatment process to be used in entrained flow gasifier due to the improved higher heating value, higher energy density, and superior combustion characteristics, proved by the ignition index, flammability index, and burnout index, highlight the effectiveness of the torrefaction process.

Outlook on the future role of robots and AI in material recovery facilities: Implications for U.S. recycling and the workforce

This study offers a comprehensive discussion of the future role of robots and artificial intelligence (AI) in U.S. recycling under different policy environments and its impact on the workforce. The state of recycling in the U.S. is changing rapidly, with techno-economic developments transforming the efficacy and sustainability of recycling and the workforce it employs. This study describes the technical, social, and policy drivers that influence U.S. municipal solid waste (MSW) management and explores pathways for more sustainable outcomes by focusing on different technology options for the sorting of recyclables in material recovery facilities (MRFs). This study presents four distinct scenario storylines for U.S. recycling by 2050 that contrast recycling and robotic futures, particularly with MRFs that maximize material recovery, worker experience, and economic competitiveness, respectively. This study finds that a recycling scenario defined by strong policy support for recycling and the addition of increasingly flexible, collaborative technology in the form of robotics coupled with AI-driven vision systems, offers the greatest potential for better results. Less certain is the role of MRFs by 2050 based on the full cost for public actors and substantial changes in private industry. Insights from this study can directly inform future techno-economic analyses, technology decisions, and policy recommendations.

SPATIO-TEMPORAL ANALYSIS OF CHANGES IN ECOSYSTEMS OF MUNICIPAL WASTE LOCALISATION AREAS USING GIS AND REMOTE SENSING DATA

The Zdovbytsia municipal solid waste (MSW) dump (the Rivne region, Ukraine) as a case study allows demonstrating informativeness of identifying waste dump sites and the adjusted areas using the spectral characteristics and texture of earth’s covers obtained from the satellite images for the different years. To identify the MSW dump in the surveyed area, direct coding features were considered, which characterized the properties of the object and are directly represented in the images. These are such features as geometric (shape, shadow, size), brightness (phototone, brightness level, color, spectral image), structural (texture, structure) ones. In addition, satellite images reliably identified the presence of discharging from the dump area, their directions, areas of unloading, the damage to herbaceous cover and other vegetation, etc. The informativeness of the study of dynamics for dump geometrical parameters, the change of its internal “structure,” the functional changes in the surrounding ecosystem elements (first, the changes in the forest stands and agricultural lands) is demonstrated. In particular, satellite image data for the period of 2003 to 2021 allow identifying the increase in a number of the Zdovbytsia MSW dump sites at the expense of adjacent forest stands. Thus, in 2003 one site of the dump is operated, whereas in 2019—already three ones, that integrated in 2021. The study of dynamics for the change of the total area of dump has revealed the increase of this area by approximately 6.25 times (from 6 521 m2 in 2003 to 20 438 m2 in 2021). In addition, the total perimeter along the contours of its stages has enlarged more than 3.35 times (from 438 to 1 466 m, respectively). The use of satellite images of higher spatial resolution in the area of about 0.6 m/pixel will specify the cases of unsatisfactory condition of the dump.

Exploring Municipal Solid Waste Dynamics in Rural Cambodia: Insights from Three Underrepresented Cities

Exploring Municipal Solid Waste Dynamics in Rural Cambodia: Insights from Three Underrepresented Cities

Pyrolysis conversion of multi-layer packaging waste under a CO2 atmosphere: Thermo-kinetic study, evolved products analysis and artificial neural networks modeling

Packaging waste such as beverage carton forms a significant part of municipal solid waste and its pyrolysis behavior, kinetics, and thermodynamics were studied. A four-stage decomposition process was revealed: dehydration below 200 ℃, paperboard degradation at 200–400 ℃, polyethylene devolatilization at 400–550 ℃, and inorganic decomposition at 550–900 ℃. The evolved products included furans and acetic acid during stage II, followed by the presence of 2-butene and 1-pentene in the subsequent stage. Apparent activation energy (Ea) were determined using model-free models, revealing a notable level of comparability among these results. The average Ea was 123.6 kJ/mol within α range of 0.10–0.60, increasing to 233.3 kJ/mol beyond that range. The most probable reaction mechanism was determined, with the one-dimensional model proving more reliable. An artificial neural network model was developed to predict the thermal degradation. The selected topology of 5*15*1 displayed a robust ability to predict the thermal data.

Supply Chain Analysis of Municipal Solid Waste Released in Hetauda Sub-Metropolitan City of Nepal

In Nepal, solid waste management is one of the major environmental issues, especially in the urban areas. While solid waste management (SWM) has become a major concern for municipalities and the country as a whole, the status of SWM is not fully understood due to the lack of SWM baseline data, which are also essential for effective planning. Such a back drop, this research attempts to assess the plastic waste released, management and recycling in supply chain in Hetauda Sub-Metropolitan City. This study revealed that about 83.8% households segregate their waste. None of the surveyed households have had public waste collection bin nearby their home whereas all households have had knowledge on solid waste management. About 63% HHs heard of importance of plastic waste recycling and all express their readiness to segregate the plastic solid waste if recycling program is set up in municipal area. Per capita waste generation per day is 141 gm out of which about 15% is plastic waste. On an average daily waste released at household level are 0.8 kg/HH which is 28.1 kg per institution. Total wastes release per day from Hetauda city is 27.4 MT and 10006.8 MT per year. About 931 MT plastic per year are gone in dumping sites in the Hetauda Sub-Metropolitan City. This study suggests that municipal office needs to develop an appropriate policy and strategy framework together with technical guidelines on key issues such as organic composting, recycling and landfill operation from dumping sites. Int. J. Soc. Sc. Manage. Vol. 11, Issue-3: 34-42.

Application of hybridized ensemble learning and equilibrium optimization in estimating damping ratios of municipal solid waste

The dynamic analysis of municipal solid waste (MSW) is essential for optimizing landfills and advancing sustainable development goals. Assessing damping ratio (D), a critical dynamic parameter, under laboratory conditions is costly and time-consuming, requiring specialized equipment and expertise. To streamline this process, this research leveraged several novel ensemble machine learning models integrated with the equilibrium optimizer algorithm (EOA) for the predictive analysis of damping characteristics. Data were gathered from 153 cyclic triaxial experiments on MSW, which examined the age, shear strain, weight, frequency, and percentage of plastic content. Analysis of a correlation heatmap indicated a significant dependence of D on shear strain within the collected MSW data. Subsequently, five advanced machine learning methods—adaptive boosting (AdaBoost), gradient boosting regression tree (GBRT), extreme gradient boosting (XGBoost), random forest (RF), and cubist regression—were employed to model D in landfill structures. Among these, the GBRT-EOA model demonstrated superior performance, with a coefficient of determination (R2) of 0.898, root mean square error of 1.659, mean absolute error of 1.194, mean absolute percentage error of 0.095, and an a20-index of 0.891 for the test data. A Shapley additive explanation analysis was conducted to validate these models further, revealing the relative contributions of each studied variable to the predicted D-MSW. This holistic approach not only enhances the understanding of MSW dynamics but also aids in the efficient design and management of landfill systems.

Factors Determining Household Waste Segregation Behaviour: An Indian Case Study

Waste represents used things or materials that are no longer required or wanted. These articles are cast off as they have stopped working or because they have ceased to be of value. Human settlements inevitably generate waste. According to UNEP's Global Waste Management Outlook 2024, the quantity of waste being generated is growing each year due to augmented economic growth accompanied with untenable consumption and production practices. In fact, global municipal solid waste (MSW) generation per year is projected to grow from 2.1 billion tonnes in 2020 to 2.7 billion tonnes in 2030 and further to 3.2 and 3.8 billion tonnes in 2040 and 2050 respectively. According to the World Bank, more than a third of waste generated globally is not managed in an environmentally sound manner and emissions related to solid waste are likely to increase to 2.6 billion tons of carbon dioxide equivalent by 2050. The present study based in Delhi with a sample of 708 households aims to understand the factors influencing the adoption of the “practice of waste segregation” by households. From our SEM and Path analysis we conclude that environmental awareness, knowledge about waste segregation and the perception about actual task of waste segregation have a significant impact on the practice of waste segregation. Environmental awareness has the largest impact followed by knowledge about how to undertake the task of waste segregation. In the light of our results, it is important and imperative to create awareness about the negative environmental impact of not segregating waste as well as demystifying the actual task of practising waste segregation.

A GIS-based suitability analysis for siting a waste-to-energy power plant in Kaduna, Nigeria

The success of any waste management system requires accurate and up-to-date data on quantity, and composition of waste. Waste generation data from households are needed to address issues relating to municipal solid wastes such as management methods, performance improvement, policy, regional and local planning, administration, cost accounting, design and operation of landfill facilities, and environmental quality. This study carried out a suitability analysis for siting a waste-to-energy power plant in Kaduna using GIS and remote sensing techniques with the specific objectives of identifying existing waste dumpsite in the study area, identifying other factors needed for waste-to-energy plant in the area, and identifying the most suitability site of waste-to-energy in Kaduna. The slop map of the study area was created using the Shuttle Radar Topographic Mission (SRTM). In the ArcGIS environment, Euclidean distance analysis was performed on institutions, rivers, dumpsites, roads, markets, transmission lines, and electricity substations. The waste-to-energy power plant suitability map was created using a multi-criteria technique by overlaying the datasets. The waste-to-energy-power-plant suitability map was made by combining the criteria. Dogon Dawa, Sabon Birinin Jaji, Ganga, Buruku, chikun, Dokwa, ikara, and Kuban are the best sites. The results of the site suitability assessment further revealed that the Makafia local government, located in the city's northern outskirts, was the most suitable area for locating the waste-to-energy power plant, covering 73686 hectares, or 26% of the total area. In addition, the map lays the groundwork for decision-makers to locate a waste-to-energy generating plant. This study shows how decision-making about solid waste management may benefit from the use of geospatial technology. Additionally, it is advised that before approving the placement of a waste-to-energy power plant, decision-makers in the study region refer to it as a reference.

Potential Use of Irradiation Techniques in Life Cycle Assessment of Polyethylene Terephthalate (PET) Plastic Waste

Plastic waste generation makes the second largest contribution of 18.6% to the total generation of municipal solid waste. Plastic waste often becomes a problem in the environment because it does not decompose easily. Polyethylene terephthalate (PET) is one type of plastic waste. This paper aims to provide a general review of the potential for using nuclear energy in the form of irradiation techniques in assessing the life cycle of PET plastic waste. The research method used is a literature study based on several related studies. The life cycle assessment method can be used to analyze potential uses and their impacts. Life cycle assessment consists of the stages of determining objectives and scope, life cycle inventory analysis, life cycle impact assessment, and interpretation. A SWOT analysis of the PET sorting program from generation sources is needed as a complement to the life cycle assessment analysis. The potential for PET irradiation techniques is in two ways, namely direct and indirect. The first way, is PET plastic waste is exposed to a certain dose of radiation directly to degrade the material properties of PET plastic waste. The second way, PET plastic waste is substituted into other products, and then a certain dose of radiation is given. At the stage of determining life cycle goals, for example, measuring the impact of irradiation techniques on the reuse or recycling of PET plastic waste. The scope is limited to “gate to gate”, from receiving PET plastic to PET irradiation. The functional unit as a basic unit can be used based on 1 kg of PET plastic. The use of nuclear power through irradiation techniques has the potential to be used in processing PET plastic. Keywords: irradiation, polyethylene terephthalate (PET), life cycle assessment

Soft sensing of NOx emission from waste incineration process based on data de-noising and bidirectional long short-term memory neural networks.

Continuous emission monitoring system is commonly employed to monitor NOx emissions in municipal solid waste incineration (MSWI) processes. However, it still encounters the challenges of regular maintenance and measurement lag. These issues significantly impact the accurate and stable control of NOx emissions. Therefore, developing a soft NOx emission sensor to complement hardware monitoring becomes imperative. Considering data noise, dynamic nonlinearity, time series characteristics and volatility in the MSWI process, this article introduces a soft sensor model for NOx emission prediction utilizing the complete ensemble empirical mode decomposition adaptive noise (CEEMDAN)-wavelet threshold (WT) method and bidirectional long short-term memory (Bi-LSTM). Firstly, the original data signal is decomposed into a group of intrinsic mode functions (IMFs) using the CEEMDAN. Subsequently, the WT processes the high-frequency IMFs that are noise-dominant. Then, all IMFs are reconstructed to obtain the denoized signal. Finally, the Bi-LSTM model is employed to predict NOx emissions. Compared to conventional modelling approaches, the model proposed in this article demonstrates the best predictive performance. The mean absolute percentage error, root-mean-squared error and average absolute error on the test set of the proposed model are 3.75%, 5.34 mg m-3 and 4.34 mg m-3, respectively. The proposed model provides a new method to soft sensing NOx emissions. It holds significant practical value for precise and stable monitoring of NOx emissions in MSWI processes and provides a reference for research on modelling key process parameters.

Microbial biomass production from enzymatically saccharified organic municipal waste and present microbial inhibitors

AbstractThe study investigated the potential of the organic fraction of municipal solid waste (OFMSW) for microbial biomass production. The compositional analysis of OFMSW showed richness in sugars, proteins, lipids, organic acids, and ethanol, suggesting promising cheap cultivation feedstock if inhibitory compounds are sustainably detoxified. The enzymatic hydrolysis with Cellic® CTec3 and AMG® 300 L BrewQ (Novozymes A/S) demonstrated excellent saccharification of sugar polymer, reaching 92% glucan hydrolysis and 70% xylan hydrolysis. However, higher enzymatic dosages led to a rise in the total organic acids content, potentially causing increased microbial inhibition. Full hydrolysate and hydrolysate after solids removal were cultivated with seven robust microbial strains. Cultivation on hydrolysate with solids showed consumption of sugars and organic acids solely by commercial backer yeast Saccharomyces cerevisiae. Removal of solids from hydrolysate resulted in increased performance of tested strains, showing consumption of measured organic acids and ethanol by S. cerevisiae, Yarrowia lipolytica DSM 8218, and Cutaneotrichosporon oleaginosus ATCC 20509. Remarkably, the investigation of biomass production revealed superior cell mass formation and detoxification by S. cerevisiae, resulting in 18.9 g of biomass/L hydrolysate with 50% of crude protein (w/w) in shake flasks and 13.2 g/L of hydrolase with 46% of crude protein (w/w) in a 5-L bioreactor. Furthermore, bioreactor cultivation confirmed organic acids and ethanol conversion into biomass, highlighting S. cerevisiae’s suitability for utilizing OFMSW for microbial biomass production. These findings contribute to advancements in biowaste-to-fodder conversion, promoting the development of a more sustainable circular economy. Graphical abstract

Comparison and mechanism analysis of MgO, CaO, and Portland cement for immobilization of heavy metals in MSWI fly ash

The significant production of municipal solid waste incineration fly ash (MSWI FA) underscores the importance of developing efficient solidification materials. This study employed MgO and CaO for immobilizing MSWI FA (with a 70% fly ash incorporation), and the immobilization effect was compared with that of Portland cement (PC). Experimental findings revealed that MgO exhibited the most effective stabilization for heavy metals (Cd, Cu, Pb, and Zn) compared to CaO and PC. XRD, FTIR, TG, and SEM analysis indicated that the principal hydration products in MSWI FA binders solidified with MgO, CaO, and PC were Mg(OH)2, CaCO3, and C-S-H gel, respectively. Mg(OH)2 efficiently immobilized heavy metals through chemical complexation and surface adsorption mechanisms. The MgO-treated MSWI FA demonstrated the highest residual fractions and the lowest easily leachable fractions. Moreover, the leaching characteristics of heavy metals were significantly influenced by the pH level, so MgO-treated MSWI FA with a leachate pH of 9.18 achieved the precipitation and stabilization of most heavy metals. In summary, this study provided an effective material selection for MSWI FA immobilization and presented a novel strategy for MSWI FA management.

Reuse potential of municipal solid waste incinerator bottom ash as secondary aggregate: Material characteristics, persistent organic pollutant content and effects of pH and selected environmental lixiviants on leaching behaviour

Increasing municipal solid waste (MSW) production poses challenges for sustainable urban development. Modern energy-from-waste (EfW) facilities incinerate MSW, reducing mass and recovering energy. In the UK, MSW incineration bottom ash (MSW IBA) is primarily reused in civil engineering applications. This study characterizes UK-produced MSW IBA, examining its pH-dependent leaching behaviour and response to environmental lixiviants. Results show predominant components include a melt phase, primary glass and fine ash aggregations, and a chemical composition dominated by SiO2 (30–50 %), CaO (∼15 %), Fe2O3 (∼10 %), and Al2O3 (∼8%). X-ray absorption near edge structure (XANES) analysis shows that Zn and Cu are most likely oxygen-bound (adsorbed to oxy-hydroxides and as oxides) with some sulphur bound. Polychlorinated biphenyls (PCBs) and polychlorinated dibenzodioxins/furans (PCDD/Fs) are well below regulatory limits, and polycyclic aromatic hydrocarbons (PAHs) were undetectable. Leaching tests indicate trace elements mobilize at pHs ≤ 6. With a natural pH of 11.3 and high buffering capacity, significant acid inputs to the MSW IBA are required to reach this pH, which are improbable in the environment. Wood chip additions increase leachate’s dissolved organic carbon (DOC) and reduce pH, but had minimal impact on metal-leaching behaviour. Synthetic plant exudate solutions minimally affect metal leaching at realistic concentrations, only enhancing leaching at ≥ 1500 mg l−1 DOC. This work supports MSW IBA’s low-risk in specified civil engineering applications.

Sustainable jet fuel from municipal solid waste–Investigation of carbon negativity and affordability claims

Addressing the challenges posed by municipal solid waste (MSW) and alternative aviation fuel is crucial for promoting circular economy and achieving carbon neutrality aligned with UN Sustainable Development Goals. While most studies in this field have focused on catalyst development for MSW-to-jet fuel conversion, this study investigates the environmental and economic performance of sustainable aviation fuels derived from MSW. Life cycle emissions for six conversion pathways were estimated to be 1187–9694 kg CO2 eq/t jet fuel. Fischer-Tropsch (FT) and Plasma FT synthesis emerged as promising options due to their lower greenhouse gas emissions (∼2000 kg CO2eq/t jet fuel) and high net present value (∼$859 million). Furthermore, Monte Carlo simulations and sensitivity analysis quantified the potential outcomes for net present value and carbon footprints. This study also discussed social acceptance, policy implications and real-world limitations for strategic decision-making and advancing the transition to alternative aviation fuels.

Physio-chemical Characterisation of Dumped Solid Waste

Landfilling is the most common practice used for the disposal of solid waste since it is the cheapest method of municipal solid waste management. The present study aims to determine the physical and chemical characteristics of dumped solid waste collected directly from Okhla landfill site (New Delhi, India) which has been declared as exhausted in 2018. These waste samples have been collected having ages beyond 20 years. Further, several laboratory tests were performed on the samples to investigate parameters namely physical composition, moisture content, density, optimum moisture content, pH, electrical conductivity, percentages of carbon (C), nitrogen (N), hydrogen (H), sulphur (S) and C/N ratio. The physical composition of samples was found to be substantially heterogenous. The mean values for moisture content and optimum moisture content were observed as 10.03% and 22.27% respectively. Moreover, the mean of density, pH and electrical conductivity were obtained as 1323.88 kg/m3, 6.44 and 3.06 mho/cm respectively. On the other hand, the elemental parameters C, H, N, S mean percentages were evaluated as 5.98%, 0.73%, 0.27% and 0.71%. Consequently, C/N ratio was evaluated as 23.46 for the samples. These results have also been compared with the MSW characteristics of Asian countries.