Municipal Solid Waste Components Research Articles

Simultaneous saccharification and fermentation of municipal cardboard waste for bioethanol production using immobilized cellulases and xylanases onto Cu-MOF

This study aims to establish a cost-effective and environmentally friendly method for bioethanol production by optimizing enzymatic hydrolysis of cardboard waste, a significant component of municipal solid waste, in combination with fermentation by Saccharomyces cerevisiae. The use of a cellulases and xylanases enzyme blend, sourced from Thermobifida fusca and Bacillus pumilus, respectively, enhances saccharification efficiency. Pre-treatment with 2 % NaOH results in a substantial 66 % saccharification efficiency at a 5 % solid/substrate loading. Further improvement in hydrolysis efficiency is achieved through enzyme immobilization on Cu-BTC-MOFs, which were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM). The immobilized enzyme blend increases saccharification efficiency to 78 %, compared to 66 % for free enzyme systems. Reusability studies demonstrate a gradual reduction in saccharification efficiency across successive cycles, reaching 71.29 % by the twelfth cycle. When applied in a simultaneous saccharification and fermentation (SSF) setup under optimized conditions, the system yields a notable bioethanol production with a yield of 0.55 g/g and a productivity of 0.20 g/L·h. This study offers potential applications in sustainable bioethanol production and waste valorization by enhancing enzymatic hydrolysis and fermentation of municipal cardboard waste. The approach demonstrates promise for scaling bioenergy production and contributes to addressing waste management challenges, supporting green energy initiatives.

Elucidating synergistic effects during co-pyrolysis of plastics and paper in municipal solid waste: Thermal behavior and product characteristics

Plastics and paper are common components of municipal solid waste (MSW), making an in-depth understanding of their interactions essential for MSW thermal conversion. In this study, the co-pyrolysis behavior of plastic and paper was investigated. Firstly, the thermal decomposition characteristics were analyzed. Secondly, the pyrolytic behavior was elucidated in a fixed-bed reactor. Thirdly, the impact of plastic melting on co-pyrolysis was clarified. Results indicated that the thermal decomposition was accelerated between 250 °C and 283 °C, while temperatures above 400 °C resulted in inhibition. During fixed-bed pyrolysis, char yields (70.7–16.9 %) were increased by 4.0 %–12.7 %. This increase was mainly due to plastic melting, which contributed 8.6 % and increased aliphatic carbon content. Besides, PVC and PET exhibited a broader melting range > 500 °C. Bio-oil yields (25.5–70.6 %) were reduced by 3.4 %–12.4 %, primarily affecting aliphatic compositions. Gas yields (3.8–6.5 %) were reduced < 400 °C but increased with temperature, involving primarily H2, CH4, C2H4, and C2H6.

Integrated municipal solid waste management using ArcGIS tools: A case of akaki-kality sub-city, addis ababa, ethiopia.

This study aimed to optimize the solid waste collection and transportation system using ArcGIS Network Analyst and location-allocation tools. The generated solid waste was characterized by proximate analysis. The generation rate and composition were determined according to standard methods. The average solid waste generation rates for households, commercial sites, institutions, and recreational places were 0.48kg/c/day, 15.03kg/fac/day, 9.32kg/fac/day, and 22.8kg/fac/day, respectively. The estimated total generation rate of the sub-city is 207,004.03kg/day and 712.13 m3/day as discarded base. Composition analysis revealed that food waste is the major component of municipal solid waste, with estimated weight and volume of 134,696.08kg and 299.46 m3, respectively. Proximate analysis indicated that food and textile wastes have relatively high moisture content and fixed carbon. Candidate pre-collection bin allocations were optimized based on factors such as road network, distribution of solid waste generators, and existing temporary dumping sites, resulting in 1052 potential bin locations. Transfer station allocation was optimized by considering land use-land cover, slope, and geology. Twelve transfer routes and four transport routes were established to efficiently serve the bins and final waste destinations. In conclusion, the study demonstrates that ArcGIS Network Analyst and location-allocation tools can effectively optimize the municipal solid waste collection and transportation system, providing a robust framework for improving waste management efficiency. However, further research is recommended to validate these findings through field application.

Novel Bacterial Consortium for Mitigation of Odor and Enhance Compost Maturation Rate of Municipal Solid Waste: A Step Toward a Greener Economy

Composting is an integral component of sustainable Municipal Solid Waste (MSW) management within the circular bio-economy platform. However, it faces challenges due to malodorous emissions that impact environmental and societal equilibrium. The present study aims to minimize odorous emissions and expedite compost maturation using a novel, efficient microbial consortium. Bacteria sourced from open dump sites in Sri Lanka were carefully screened based on concurrent enzyme production. Five developed consortia were tested for their performance in reducing malodors during the composting process of MSW. Consortium No. 5 (C5), comprised of Bacillus haynesii, Bacillus amyloliquefaciens, and Bacillus safensis, demonstrated outstanding performance with a significant (p &lt; 0.05) reduction in odorous emissions. Additionally, consortium C5 exhibited impressive control over gas emissions, maintaining VOC, CH4, NH3, and H2S concentrations within ranges of 0.5-6 ppm, 0.5-0.8 ppm, 0.3-0.5 ppm, and 0.5-0.6 ppm, respectively, compared to control concentrations of 4.5-10.2 ppm, 0.5-5.5 ppm, 0.3-5.5 ppm, and 0.5-6.4 ppm, respectively. Additionally, comprehensive Electronic nose (E-nose) analysis substantiated C5’s efficiency in attenuating Methane-Aliphatic compounds, Sulfur and Aromatic compounds, along with low-polarity aromatic and alkane compounds, all with statistical significance (p &lt; 0.05). Further, the developed consortium could reduce the composting time from 110 ± 10 days to 17 ± 3 days, offering a sustainable solution for global MSW management.

Valorizing Combustible and Compostable Fractions of Municipal Solid Waste to Biochar and Compost as an Alternative to Chemical Fertilizer for Improving Soil Health and Sunflower Yield

Reduced reliance on synthetic chemical fertilizers necessarily requires using renewable biomaterial-derived soil organic amendments (SOAs) in agriculture for sustained retention of nutrients through improvement in the soil organic matter (SOM). SOM replenishment through SOAs derived from wasted materials could help in its valorization by furthering the sustainability prospects of agronomic crop production systems. In the current study, compost (CP) and biochar (BC) were derived as SOAs from combustible and compostable fractions of municipal solid waste (MSW) for their potential valorization by adding SOAs as potential sustainable sources of nutrients as a replacement of chemical fertilizers (CF) for sunflower crops cultivated in potted soils. The experimental design included quadruplicated soil application of MSW-derived BC and CP in discrete and combined forms, each in three doses (% w:w), viz., low (L), medium (M), and high (H), i.e., BC-L, BC-M, BC-H; CP-L, CP-M, CP-H; and BC + CP-L, BC + CP-M, BC-CP-H. The results showed that, compared to the control (soil only), the sunflower growth and harvestable yield were significantly greater in BC + CF with a medium dose and were comparable to the growth and yield obtained in soils with CF. Sunflower growth in the discrete SOAs remained less than in the combined SOAs (BC + CP) and was attributed to the comprehensive soil health improvement rendered by the applied SOAs. The soil health improvement factors included SOM, CEC, and concentrations of total and available NPK. The dose-effect comparison of the SOAs showed highly variable trends, i.e., the sunflower growth did not correspond with the increase in dose of the SOAs. It is concluded that the combined application of BC + CP derived from MSW components at a medium dose could act as a potential alternative to CF. The developed approach resulted in MSW valorization, which improved soil health and yielded a better sunflower crop.

How Indonesia’s Cities Are Grappling with Plastic Waste: An Integrated Approach towards Sustainable Plastic Waste Management

In Indonesia, plastic constitutes the second largest component of municipal solid waste; however, 58% remains uncollected. Most plastic recycling depends on informal sectors, accounting for only 10% of the total, leaving the remainder to potentially harm the environment. This paper analyzes how cities in Indonesia have tackled their plastic waste problems from the perspective of the integrated sustainable waste management framework. This study focuses on plastic waste management (PWM) in three cities: Bandung, Yogyakarta, and Magelang. Data were collected from 41 semi-structured interviews, a plastic waste composition data analysis, and site visits. The research outcomes include a comprehensive analysis of stakeholder roles, plastic waste flow, plastic waste composition data, and various challenges in PWM. This study identifies three main stakeholders in collecting plastic wastes: the Department of Environment as the main local government body, community-based waste banks, and private waste management companies. Most recyclable plastic waste is recovered through waste banks and private collection services. In 2022, the predominant types of plastic waste in Bandung, Yogyakarta, and Magelang City were soft plastics, thick plastics, and hard plastics, respectively. The challenges for the PWM stem from various aspects in political, legal, and institutional; environmental; financial and technical; and socio-cultural spheres. Positive trends towards an integrated system are observed, although full integration has not yet been achieved. The research recommends a multi-stakeholder cooperative approach involving municipal authorities, waste banks, and private collectors, responsive to local conditions and emphasizing sustainability aspects throughout waste management stages for a sustainable resource recycling in developing countries.

Thermal Analysis of Combustible Components of Municipal Solid Waste

The use of municipal solid waste as a raw material for alternative fuel is a promising direction for waste recycling and substitution of solid fossil fuels. Therefore, selecting of fuel composition and studying of its properties is an urgent task. The aim of this work is thermal characteristics analysis of the combustible components of municipal solid waste, which are the most common in Ukraine, for further selection of a fuel composition that will satisfy the consumer's requirements. The goal is achieved by studying the thermal destruction of samples by thermogravimetry and differential thermal analysis when materials are heated to 1000 ºС in the presence of air oxygen. Paper, cardboard, plastic, biodegradable film, textiles, leather, wood were investigated in this work. The most important results are the received data on the characteristic temperatures of destruction stages, content of water, organic and mineral substances, ash, as well as the calculated values of rate and conditional thermal effect of decomposition of organic substances. Strong formation of gaseous substances was registered for samples of polyethylene and biodegradable film, polyethylene terephthalate and cotton fabric. These features should be considered in the technologies of production and combustion of fuel. The significance of the results also lies in the fact that it is recommended to use data on the thermal stability of materials in order to prevent their ignition during drying when developing fuel production technology. In addition, the calculated values of the conditional thermal effect made it possible to evaluate the thermal characteristics of the studied materials as components of solid alternative fuels.

Development of municipal solid waste management guidelines in biological crisis based on international experiences and considering local techno-economic characteristics

In addition to health consequences, the Covid-19 pandemic has had important effects on the environment and lifestyle. Municipal solid waste management faced serious challenges due to consequence of the Covid-19 pandemic. In this study, the effects of the Covid-19 pandemic on the quantity and composition of municipal solid waste in Tehran were investigated. The international experiences of municipal waste management in the Covid-19 pandemic were reviewed and the results were used to develop a guideline for waste management in epidemic conditions adapted to local characteristics. The results showed that changes in the quantity of municipal solid waste affected by the Covid-19 pandemic had temporal and spatial variation. The most change in quantity by 15.81% was seen at the beginning of the pandemic, and non-recyclable waste had the most ratio change among the components of municipal solid waste (144%). The emergence of scattered point sources of infectious waste generation was the most important consequence of the epidemic in municipal solid waste management. These experiences were the basis for defining a guideline for the management of municipal solid waste in biological crises. A guideline in six activities and more than 90 items based on the local characteristics such as available equipment, general culture, local economy, and quantitative changes was defined.

Transitioning towards circular economy through municipal solid waste analysis and characterisation using SowaCLINK software

Municipal solid waste constitutes environmental challenges globally, especially in developing countries, due to increasing waste generation, population growth, inadequate infrastructure, lack of data and poor planning. This study aims to conduct a comprehensive waste audit on the municipal solid waste generated in Aba, a metropolis in southeastern Nigeria. Aba is a commercial city considered the messiest because of the massive municipal solid waste generation and poor management. The study investigated the energy potential and waste regeneration. Municipal solid waste data was sought to provide insight into the quantity and composition of municipal solid waste. The methodology was site-based, in line with the standard test method for determining unprocessed municipal solid waste (ASTM-D5231-92) and SowaCLINK software, a computer-based environmental application, was used for characterization. Linear extrapolation was adopted to quantify the rate of municipal solid waste generated. The geometric mean was applied to forecast the area’s population for a 10-year design period. The chemical elements of the characterized municipal solid waste were utilized based on the ASTM-D5291 standard for municipal solid waste thermochemical conversion, and the high and low heating values were analyzed. The outcomes provided energy recovery potential, the electrical power potential, and the power to the grid of electrical power of the municipal solid waste. The results obtained were 0.7813 kg/p/d and 490,268 t/y for a population of 1,719,185 persons. The percentage of the municipal solid waste components with energy potential was 71%, comprising 48% combustible and 23% organic components on average. The high heating value computed was 176.5 MJ/kg, and the low heating value was 14 MJ/kg. The energy recovery potential was 3,709,463 MWh, the electrical power potential was 38,680 MW, and the power to the grid was 26.1 MW daily. The research reveals a promising direction in transitioning from the linear economy of municipal solid waste management toward implementing an integrated sustainable municipal solid waste management based on the circular economy model. The study recommends adopting detailed steps to proffer solutions to the environmental challenges associated with municipal solid waste in most low-middle-income countries to achieve sustainable municipal solid waste management while generating electricity and bio-fertilizers through incineration and anaerobic digestion.

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.

Mechanical strength changes of combustible municipal solid waste components during their early pyrolysis stage and mechanism analysis.

Implementation of municipal solid waste (MSW) source segregation leads to a more convenient recycle of combustible MSW components. Textiles, plastics and papers are commonly available combustible components in MSW. Their shredding is conducive to resources recovery. But these components usually have high tensile strengths and are difficult to shred. To understand their mechanical strength changes in their early pyrolysis stage will help to address this problem. In this study, a universal electronic testing machine was used to determine the breaking strengths of the materials including cotton towel, polyethylene glycol terephthalate (PET), ivory board (IB), kraft paper (KP) and wool scarf in the temperature range of 30-250°C under N2 atmosphere, and the mechanisms of their strength changes were explored. The reaction force field molecular dynamics (ReaxFF-MD) simulation was used to explain the decomposition behaviours of different sugar groups of hemicellulose in cotton and paper and the change of van der Waals energy of wool during their early pyrolysis stages. The results showed that breaking strengths of all the combustible MSW components reduced as the temperature increased. The breaking strength of PET was found to have the highest descent rate with increasing temperature, then the descent rates of wool and cotton came as the second and third, respectively. Compared with cotton, the breaking strengths of KP and IB decreased more slowly. As the temperature increased, the breaking strength of cotton reduced mainly due to the decomposition of the glucuronic acid in hemicellulose, and the reduction was characterized by CO2 release. The breaking strength reduction of PET was caused by its molecular chain being relaxed. The breaking strength reduction of wool was firstly caused by the decrease in the van der Waals energy between its molecules, and then caused by molecular chain breaking. In addition, in order to understand the influence of material size on the breaking strength change during thermal treatment, the breaking strengths of cotton yarn bundles were correlated with their yarn number and temperature. This study lays the foundation for understanding changes in mechanical strengths of combustible MSW components during their early pyrolysis stage.

SOLVING ENVIRONMENTAL PROBLEMS BY RECYCLING MUNICIPAL SOLID WASTE

Multifaceted human activities are accompanied by the release of large amounts of greenhouse gases into the atmosphere, which is one of the reasons that can lead to disruption of natural processes occurring in the atmosphere. About 80% of greenhouse gas emissions come from industrial processes. Increasing concentrations of greenhouse gas emissions into the atmosphere, as well as lack of recycling or improper disposal of waste, can upset the balance of the ecosystem. In addition to industrial waste, municipal solid waste (MSW) is a source of greenhouse gas emissions into the atmosphere. When solid waste is used as a renewable energy source, significant amounts of carbon dioxide are released into the atmosphere. In this regard, the disposal of solid waste waste and subsequent processing can play a certain role in solving a serious environmental problem that concerns all of humanity. The article is devoted to the issue of environmental problems caused by the accumulation of MSW, which can become potentially dangerous for environment and human health. The objective of the study was to study the possibility of using fractions separated by a large MSW processing center operating in the country as secondary raw materials, as well as developing an environmentally friendly method for processing MSW for their disposal. The possibility of transforming the organic component, separated by sorting during solid waste disposal, into organic-mineral fertilizers has been studied. To neutralize the raw organic component of MSW from helminths, mineral waters of Azerbaijan were used, coming to the surface at a temperature of 25-75°C, containing 5-18% H2S As a mineral component of the fertilizer, phonolite is used, which is part of the rock of volcanic origin in the Lerik region of Azerbaijan, containing potassium, necessary for the development of plants. To eliminate the acidity of the resulting pulp before granulation, local shell rock was used. The neutralized organomineral component of MSW was mixed with pre-crushed phonolite until the nutrients were completely transferred into the pulp, followed by drying in an oven for 1.5-2 hours at a temperature of 100-110°C. The resulting mass was cooled for 30 minutes to ripen, then shell rock was added. During the processing process, organic compounds present in MSW undergo hydrolytic destruction. A technological process has been developed for producing potassium-containing organomineral fertilizer by processing the organic component of solid waste using local natural resources, which is protected by an AR patent. Keywords: ecology, waste management, municipal solid waste, recycling, organomineral fertilizers.

Substantiation of the main parameters of a hammer crusher for grinding municipal solid waste

The scientific novelty of the research lies in the determination and substantiation of the rational values of the main parameters of a hammer crusher designed for grinding organic components of municipal solid waste. A method has been developed for calculating the speed and effort, as well as the maximum elastic-plastic deformation of the components of the waste due to the collision of the waste against each other, against the wall of the working chamber of the crusher, as well as against knives welded on the walls of the working chamber at different heights at an angle of 120 degrees with each other. The aim of the study is to develop a hammer crusher design with low energy and material consumption with increased technical and operational performance. As a result of the experimental studies, the dependences of the crusher performance on the number of revolutions of the rotor shaft, on the light area of the grates, and on the diameter of the rotor were obtained. The processing of the obtained experimental data made it possible to obtain a mathematical model that adequately describes the process of crushing the organic components of the waste in a hammer crusher. Design and production of hammer crushers with rational parameters will reduce energy and material consumption by approximately 1.5-2.0 times compared to traditional designs.

Selection of an optimal set of machines for sorting and crushing municipal solid waste

The article is dedicated to the selection of the optimal set of machines for sorting and crushing municipal solid waste based on its properties and accumulation rates. Considering the properties of waste and technologies for its collection, a new technological scheme for processing municipal solid waste was developed and, based on this scheme, the optimal set of machines was selected. In addition, the research conducted to determine the fractional composition of the waste made it possible to substantiate the diameter of holes in the drum screen mesh. Based on the analysis of the morphological composition of the waste at the end of the technological chain, the type of crusher design was determined and the main parameters of the hammer crusher were substantiated in connection with the technological processing. The optimal set of machines will make it possible to process the components of municipal solid waste for use in the form of secondary raw materials with the least material and time costs.

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.

Evaluation of the Methane (CH4) Generation Rate Constant (k Value) of Municipal Solid Waste (MSW) in Mogadishu City, Somalia

Landfills are the third largest source of the greenhouse gas methane, contributing to 25% of global warming. Therefore, the characterization of national municipal solid waste (MSW) and estimation of methane generation rate are very important for the solid waste management (SWM) toward sustainable development goal no. 13, climate action. This study presents (a) an assessment of daily MSW generation, (b) the characterization of MSW, and (c) an evaluation of the methane generation rate constant (k value) in Mogadishu, Somalia. The MSW samples were collected from three (3) sampling zones (Zones 1, 2, and 3; 204 households) and weighted (kg). Next, the waste generation per person per day was estimated. The MSW characterization includes sorting (based on plastic/polythene, food wastes, wood, metals, yard waste, paper/cardboard, textile, glass/ceramic and miscellaneous components, %), the determination of bulk density (kg/L), and measuring moisture content (%). The k values were evaluated from the percentages of different components in MSW based on first-order decay models. Mogadishu city generated 1671.03 kg MSW per week (maximum on Friday: 348.72 kg, and minimum on Monday: 152.04 kg). The total mean MSW generation rate observed in this study was 0.2 kg/person/day. The solid waste generation found was in the decreasing order of food waste &gt; plastic/polythene &gt; yard waste &gt; miscellaneous &gt; papers/carboard &gt; wood &gt; glass/ceramic &gt; textiles &gt; metals by weight. The average bulk density was found to be 0.269 kg/L. The average moisture content was ranged from 61.6 to 73%. The total k values were categorized as fast (Zone 1: 0.216053 yr−1, Zone 2: 0.228739 yr−1, and Zone 3: 0.244595 yr−1) and moderate (Zone 3: 0.244595 yr−1) degradation. This research serves as Somalian MSW baseline data and projected the methane generation rate from the MSW production in the country. The MSW sorting may reduce the impact of global warming and is highly recommended for better SWM in the future.

STRATEGIC OBJECTIVES OF SOLID MUNICIPAL WASTE MANAGEMENT IN SEVASTOPOL

One of the trends in municipal solid waste (MSW) management is the phased implementation of the Zero Waste concept based on the separate waste collection and its subsequent processing into useful products and expanding its reuse. This concept can be implemented within the municipal waste flow management, where it is relevant to search for low-cost ways to reduce the volume of deposited waste in conditions of limited funding. The paper examines the problems of managing municipal waste flows using the example of Sevastopol. Elements of the promising structural and technological scheme for the selective waste collection were developed, and strategic goals for managing municipal solid waste in a federal city were determined. Economic and infrastructural barriers that prevent the expansion of the range of materials and raw materials isolated from MSW were revealed. It is recommended to increase the volume of processed organic waste to produce compost: implementation of technologies for anaerobic biofermentation of organic components of MSW that are capable of biological decomposition, technologies for aerobic biofermentation of garden waste (green waste) mixed with municipal sewage sludge; thermal processing of alternative fuels from waste with heat recovery and full use of the waste energy resource using environmentally friendly and waste-free technologies.

Roles of ageing on the physical, chemical and mechanical parameters of a prototype municipal solid waste

ABSTRACT This study is mainly aimed at exploring effects of the aging-induced chemical decomposition of Municipal Solid Waste (MSW) on the shear response and physical properties of locally available MSW of Fars province, Iran, at its in-situ condition. To this end, a large direct shear device (1×1×1.1 m3) is designed, fabricated and employed to evaluate the parameters of the failure envelop at plane strain condition representing slopes of engineered landfills. Bulk disturbed samples of fresh MSW are exhumed from an operational disposal site to be implemented into the study and subsequently remolded in the large-scale shear box. Four drained shear tests are performed under a variety of vertical stresses. Next, intact components of MSW are landfilled over a period of 3, 6, and 9 months. Similar shear experiments are conducted at the end of each mentioned time interval. Mechanical behavior of MSW is completely frictional and internal friction angle of the studied MSW non-linearly increases with time from 44.2º to 55.7º. The stress-strain response is almost bilinear over a wide range of displacement. The decomposition process is further clarified in light of results of pH tests conducted on the leachate of the MSW at the end of various landfilling time intervals.

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.