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1.
Waste Manag ; 124: 314-324, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33647557

RESUMO

Municipal solid waste (MSW) management is an important challenge in developing and emerging countries, where two realities co-exist. On the one hand, their metropolitan cities exhibit an integrated MSW system with a specialized fleet for the collection and landfills for the final disposal, concentrating on environmental initiatives such as municipal recycling programs. On the other hand, their regional cities show an MSW system based on adapted transports for collection and open dumps for final disposal. Besides, they face other environmental problems due to local conditions. This research proposes a life cycle assessment (LCA) approach to close the gap between these two realities. In particular, we study the city of Valdivia (Chile), one of the main regional capitals of South America, which shares similarities with other southern regional cities in the Global South. This city disposes 95% of its MSW in open dumps and presents one of the highest environmental pollution rates in Latin America. We analyze the greenhouse gas (GHG) emissions and energy performance of six scenarios, seeking a solution for these problems. The results obtained show that a waste-to-energy scenario would generate savings of GHG emission and particulate matter, reaching 11.3% and 21.8%, respectively. Using our LCA approach, we can provide environmental evidence to highlight the importance of improving MSW management in regional cities, closing the gap with MSW management in metropolitan cities, and contributing to national targets such as United Nations Sustainable Development Goals and Nationally-Determined Contributions.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Animais , Cidades , Países em Desenvolvimento , Estágios do Ciclo de Vida , Resíduos Sólidos/análise , América do Sul
2.
Waste Manag ; 124: 385-402, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33662770

RESUMO

Artificial neural networks (ANNs) have recently attracted significant attention in environmental areas because of their great self-learning capability and good accuracy in mapping complex nonlinear relationships. These properties of ANNs benefit their application in solving different solid waste-related issues. However, the configurations, including ANN framework, algorithm, data set partition, input parameters, hidden layer, and performance evaluation, vary and have not reached a consensus among relevant studies. To address the current state of the art of ANN application in the solid waste field and identify the commonalities of ANNs, this critical review was conducted by focusing on a modeling perspective and using 177 relevant papers published over the last decade (2010-2020). We classified the reviewed studies into four categories in terms of research scales. ANNs were found to be applied widely in waste generation and technological parameter prediction and proven effective in solving meso-microscale and microscale issues, including waste conversion, emissions, and microbial and dynamic processes. Given the difficulty of data collection in many solid waste-related issues, most studies included a data size of 101-150. For mathematical optimization, dividing the data into training-validation-test sets is preferable, and the training set is supposed to account for ~70%. A single hidden layer is usually sufficient, and the optimal numbers of hidden layer nodes most likely range from 4 to 20. This review is supposed to contribute basic and comprehensive knowledge to the researchers in general waste management and specialized ANN study on solid waste-related issues.


Assuntos
Resíduos Sólidos , Gerenciamento de Resíduos , Algoritmos , Redes Neurais de Computação , Resíduos Sólidos/análise
3.
Waste Manag ; 125: 103-111, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33677180

RESUMO

Currently, centralised plants are the most favoured approach for the anaerobic treatment of the organic fraction of municipal solid waste (OFMSW). However, centralised solutions imply certain environmental impacts, which prevent large-scale implementation of the anaerobic digestion (AD). As a result, we are digesting <5% of organic waste both in Europe and the USA even today. Pursuing the criteria for maximising the balance between profit and impacts, an innovative layout with the ultimate goal of promoting the use of small, decentralised AD plants is proposed. In this study, source-separated OFMSW (SS-OFMSW) was treated in a mesophilic plug flow reactor by applying an atypical combination of conditions such as high SS-OFMSW solid content (214.5 g·kg-1), high organic loading rate (6.2 kg VS·m-3·d-1), and no dilution or co-substrate addition. A suitable and an efficient mixing system is essential to control the process. Accordingly, the process was stable in a single-stage reactor, in the absence of digestate recirculation, obtaining specific gas production of 0.67 m3·kg-1 VS in terms of biogas and 0.41 m3·kg-1 VS in terms of methane. High reactor volume exploitation and small plant construction were feasible, reaching a gas production rate of 4.5 m3·m-3 d-1. The estimated costs in terms of capital and operating expenditure are expected to realize gross economic sustainability of full-scale installation.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Anaerobiose , Reatores Biológicos , Europa (Continente) , Metano , Resíduos Sólidos/análise
4.
Waste Manag ; 125: 249-256, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33713870

RESUMO

Environmental damage cost can measure the impact of pollution caused by human activity on final safeguard subjects from endpoint perspective. Application of environmental damage cost to municipal solid waste (MSW) management is still rare. To fill such a research gap, this study established a MSW environmental damage cost assessment method using Life Cycle Impact Assessment Method based on Endpoint (LIME) model. Four types of environmental damage cost, namely, primary productivity, social assets, biodiversity and human health for waste treatment were investigated in the city of Shanghai. Results show that the environmental damage cost was 113.7, 116.9, 140.0, 144.0 and 170.8 million dollars in Shanghai from 2014 to 2018, respectively. Damage cost of social assets was the dominant component, accounting for about 55%. Landfill mainly caused social assets damage cost, while incineration mainly caused human health damage cost. Scenarios analysis further revealed that after implementing MSW separation, the total environmental damage cost could be reduced by about 1/3. The best MSW treatment method is fermentation, followed by compost, incineration and landfill, with unit environmental damage cost being 0.22, 4.51, 16.04 and 23.47 USD/ton, respectively.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , China , Cidades , Humanos , Incineração , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
5.
Waste Manag ; 125: 316-327, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33725517

RESUMO

Low bulk density, variable moisture content, and particle size of municipal solid waste (MSW) create feeding, handling, storage, and transportation challenges. In this study, MSW bales were size-reduced in stage-1 and stage-2 hammer mill grinders fitted with 50.8-mm and 6.35-, 12.7-, and 19.05-mm screens. Ground MSW was densified further in a pilot-scale briquette press by varying moisture content in the range of 10-25% wet basis (w.b.). At 40% (w.b.) MSW moisture content, the stage-1 grinder fitted with a 50.4-mm screen took about 136kWh/ton, while the stage-2 grinder fitted with a 19.05-mm screen took about 151kWh/ton. The bulk density of MSW after stage-1 and stage-2 grinding was about 25-50 kg/m3. Unit bulk and tapped density were in the range of 680-850 kg/m3, 478-315 kg/m3, and 346-540 kg/m3 post briquetting, and 591-830 kg/m3, 295-458 kg/m3, and 319-519 kg/m3 post five days of storage at 20 °C. The durability was about 93.40-98.54% post briquetting, and after five days of storage. Increasing the moisture content and screen size decreased density and improved durability. Briquetting energy increased to 120 kWh/ton at a higher moisture content and larger grind size. MSW flow characteristics improved after briquetting. Higher lignin content (≈30%) and calorific value (19-21 MJ/kg) suggest MSW is suitable for thermochemical conversion. Ash content in the MSW was in the 11.9-14.8% range. CT-scan images of the briquettes showed a network of interconnected pores formed due to compression of various MSW fractions.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Pressão , Resíduos Sólidos/análise
6.
J Environ Manage ; 286: 112140, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33652254

RESUMO

The COVID-19 pandemic has imposed a global emergency and also has raised issues with waste management practices. This study emphasized the challenges of increased waste disposal during the COVID-19 crisis and its response practices. Data obtained from the scientific research papers, publications from the governments and multilateral organizations, and media reports were used to quantify the effect of the pandemic towards waste generation. A huge increase in the amount of used personal protective equipments (facemasks, gloves, and other protective stuffs) and wide distribution of infectious wastes from hospitals, health care facilities, and quarantined households was found. The amount of food and plastic waste also increased during the pandemic. These factors caused waste treatment facilities to be overwhelmed, forcing emergency treatment and disposals (e.g., co-disposal in a municipal solid waste incinerator, cement kilns, industrial furnaces, and deep burial) to ramp up processing capacity. This paper discussed the ways the operation of those facilities must be improved to cope with the challenge of handling medical waste, as well as working around the restrictions imposed due to COVID-19. The study also highlights the need for short, mid, and longer-term responses towards waste management during the pandemic. Furthermore, the practices discussed in this paper may provide an option for alternative approaches and development of sustainable strategies for mitigating similar pandemics in the future.


Assuntos
Eliminação de Resíduos de Serviços de Saúde , Eliminação de Resíduos , Gerenciamento de Resíduos , Humanos , Pandemias , Resíduos Sólidos/análise
7.
Sci Total Environ ; 772: 144954, 2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-33571777

RESUMO

The organic fraction of municipal solid waste (OFMSW) is an appealing feedstock for bioethanol production due to its richness in cellulosic materials. After fermentation and distillation, the remaining residue constitutes a source of unconsumed carbohydrates, proteins and lipids. These macromolecules can be further used via anaerobic digestion (AD) for bioenergy purposes to offset bioethanol production costs. The present study evaluated the methanogenic potential of the whole fermented residue from a selective collection of OFMSW in a semicontinuous AD at 35 °C (HRT 40 days and OLR 2.09 g VS/Ld). The experimental results showed a methanogenic yield of 212 ± 5 mL CH4/g VSin (corresponding to a COD removal of 47 ± 1 %). Microbial analysis revealed key roles of species belonging to Firmicutes (65 %), Bacteroidetes (25 %) and Euryarchaeota (0.5-1 %). Methanosarcina archaea was highlighted as a robust methanogen crucial for methane production in a process in which the stability might be compromised by potential NH4+-N and VFAs inhibitions. This study indicated that the sequential combination of these two biochemical processes (fermentation and anaerobic digestion) allow to further exploit organic residues for their conversion into a marketable bioenergy product.


Assuntos
Microbiota , Eliminação de Resíduos , Anaerobiose , Reatores Biológicos , Metano , Resíduos Sólidos/análise
8.
Waste Manag ; 124: 118-127, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33611156

RESUMO

Although the informal sector of waste collection has an important role in income diversification for the poor and contribution to waste recycling, this sector is still not recognised in any government official policies and is usually underestimated in the Mekong Delta of Vietnam. This paper employs a systems thinking approach to analyse the crucial roles of the informal sector in solid waste management (SWM) system in Vietnam. From a circular economy viewpoint, the flow diagram was built for the first time, which could integrate the actors and activities of the informal sector into a wider SWM system in Vietnam. The map focuses on analysing the contributions and activities of the informal sector, focusing on its roles and impacts on the recycling system. This paper then employed the systems thinking approach to further analyse the systematic problem of the informal sector. The analysis builds on the field survey including elements and key driving forces of the systems with 36 scrap dealers, 127 scrap buyers, and 760 households and in-depth interviews with experts in the Mekong Delta region, Vietnam. Based on the practices and experience in waste-related activities of informal sector, this sector should be integrated into the general waste management process. With the relevance of informal systems, the authorities could establish an effective waste recycling system, and improve the livelihoods and working conditions of those involved, especially the poor.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Cidades , Setor Informal , Reciclagem , Resíduos Sólidos/análise , Desenvolvimento Sustentável , Vietnã
9.
Waste Manag ; 124: 136-143, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33621757

RESUMO

Bottom ash co-disposed in landfills accelerates geotextile clogging and decreases landfill stability. As the main contributor to clogging, bio-clogging may be associated with quorum sensing (QS) in microbial communities. This study investigated the potential roles of acyl-homoserine lactones (AHLs)-mediated QS in geotextile bio-clogging under different landfill conditions, including municipal solid waste landfill and bottom ash co-disposal landfill. The unit area of geotextile bio-clogging mass in the municipal solid waste landfill (MSW_G) ranged from 5.2 × 10-3 to 8.2 × 10-3 g/cm2, while it was in the range of 8.4 × 10-3 to 1.2 × 10-2 g/cm2 in the bottom ash co-disposal landfill (BA_G). Two types of AHLs were detected and the total AHLs content in the MSW_G (1,616.9 ± 103.8 ng/g VSS) was half of that in the BA_G (3,233.0 ± 646.8 ng/g VSS). High contents of the AHLs could increase bio-clogging. The bio-clogging was also attributed to QS genes and extracellular polymeric substances (EPS). EPS aggregation was stimulated due to the higher Ca2+ and Mg2+ in the BA_G. These results suggested that the co-disposal of bottom ash could increase the AHLs content, resulting in accelerated bio-clogging.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Acil-Butirolactonas , Cinza de Carvão , Percepção de Quorum , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
10.
Waste Manag ; 124: 293-302, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33640669

RESUMO

This study quantifies and compares the cost of municipal solid waste (MSW) management systems under different scenarios using life cycle cost (LCC) analysis approach. LCC analysis was performed for six integrated MSW management scenarios for Mumbai city, India which generates over 9000 metric tonnes of MSW daily and disposes most of it in open dumps. The scenarios are the combinations of recycling, composting, anaerobic digestion, incineration with electricity generation, and landfill with biogas recovery. To perform LCC analysis of scenarios, present worth method was used. The present worth of operations and maintenance (O&M) cost and revenue generated was estimated using a discount rate of 11.25% for a 20-year life span. Results show that the incineration based scenario is the most cost-intensive option with a net LCC of US$38 per tonne of MSW due to the high capital cost involved in case of incineration. While the scenario with a combination of recycling and sanitary landfill was the most economically viable option with a net LCC of US$19 per tonne of MSW due to comparative lower operating cost. The sensitivity analysis shows that the O&M cost was the most sensitive parameter and a change of ±10% and ±20% in O&M cost, the net LCC of scenarios changes in the range of 14-33% and 29-65%, respectively. This study provides an economic comparison of MSW treatment scenarios from a life cycle perspective, which facilitates the decision-making process for improvement in cost estimation and planning of waste management strategies in India.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Animais , Cidades , Custos e Análise de Custo , Índia , Estágios do Ciclo de Vida , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
11.
J Environ Sci (China) ; 102: 99-109, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33637269

RESUMO

Increase of sewage sludge (SS) has led to the construction of more incineration plants, exacerbating to the production of SS incineration residues. However, few studies have considered the mass balance of elements in large-scale SS incineration plants, affecting the residues treatment and utilization. In this study, flow analysis was conducted for major and trace elements in the SS, the fly ash (sewage sludge ash, SSA) and bottom ash from two large-scale SS incineration plants. The elemental characteristics were compared with those of coal fly ash (CFA), and air pollution control residues from municipal solid waste incineration (MSWIA), as well as related criteria. The results showed that the most abundant major element in SSA was Si, ranging from 120 to 240 g/kg, followed by Al (76-348 g/kg), Ca (26-113 g/kg), Fe (35-80 g/kg), and P (26-104 g/kg), and the trace elements were mainly Zn, Ba, Cu, and Mn. Not all the major elements were derived from SS. Most trace elements in the SS incineration residues accounted for 82.4%-127% of those from SS, indicating that SS was the main source of trace elements. The partitioning of heavy metals in the SS incineration residues showed that electrostatic precipitator ash or cyclone ash with high production rates were the major pollutant sinks. The differences in some major and trace elements could be indicators to differentiate SSA from CFA and MSWIA. Compared with related land criteria, the pollutants in SSA should not be ignored during disposal and utilization.


Assuntos
Metais Pesados , Oligoelementos , Cinza de Carvão , Incineração , Metais Pesados/análise , Esgotos , Resíduos Sólidos/análise
12.
Waste Manag ; 123: 131-141, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33582400

RESUMO

The objective of this study was to assess the influence of moisture enhancement strategies on biodegradation of municipal solid waste (MSW) in laboratory-scale reactors. Moisture enhancement strategies were varied with respect to dose volume (40, 80, 160, and 320 L/Mg-MSW) and dose frequency (dosing every ½, 1, 2, and 4 weeks). Biodegradation was evaluated based on methane generation to assess (i) the lag-time between the start of liquid dosing and onset of methane generation and (ii) the first-order decay rate for methane generation. In general, the decay rate increased with an increase in dose volume for a given dose frequency. In addition, trends of increasing decay rate and decreasing lag-time were observed for an increase in dose frequency for reactors operated with dose volumes of 40, 80, and 160 L/Mg-MSW. A key conclusion from this study was that reactors with more aggressive moisture enhancement attained more rapid methane generation that initiated at shorter elapsed times following the onset of dosing. An assessment of liquid dosing per month indicated that there were more pronounced impacts of increasing decay rate and decreasing lag-time as moisture enhancement increased from 40 L/Mg-MSW/month to 320 L/Mg-MSW/month as compared to the impact on both variables for an increase in liquid dosing above 320 L/Mg-MSW/month.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Biodegradação Ambiental , Reatores Biológicos , Metano , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
13.
Environ Sci Pollut Res Int ; 28(14): 17468-17481, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33394448

RESUMO

Phosphogypsum (PG) is a solid waste product of the wet-process phosphoric acid industry that accumulates in large amounts on the ground, forming PG ponds. In recent years, the amount of PG produced and discharged into ponds has increased significantly with the increase in the market demand for phosphate fertilizers. To enrich the basic knowledge of PG properties and provide basic data for the stability analysis of PG dams, a series of laboratory geotechnical tests, including permeability tests, compressibility tests, triaxial shear tests, and dynamic triaxial tests, were conducted in this study. During the preparation of the test samples, solubility and high-temperature dehydration of PG were considered. The results indicated that PG exhibits medium compressibility and medium to weak permeability characteristics. The stress-strain curves of the triaxial shear tests were divided into three typical stages: initial deformation stage, strain hardening stage, and destruction stage. With increasing dry density and consolidation confining pressure, both the shear strength and deformation modulus significantly increased. The relationship between the deformation modulus and confining pressure gradually changed from linear to logarithmic with increasing density. The liquefaction resistance curves (CSR-NL curves) of PG were expressed by power functions. With increasing dry density, the curves shifted higher and became steeper. Compared with the Hardin-Drnevich model, the Davidenkov model was found to be more suitable for describing the relationship between the dynamic shear modulus ratio and damping ratio of PG and the dynamic shear strain. Furthermore, compared with those of tailings and natural soils, the engineering mechanical properties of PG were relatively poor, which may be related to its uniform particle distribution and neat particle stacking structure.


Assuntos
Eliminação de Resíduos , Sulfato de Cálcio , Fósforo , Resistência ao Cisalhamento , Resíduos Sólidos/análise
14.
Waste Manag ; 122: 49-54, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33485254

RESUMO

COVID-19, declared a global pandemic by the World Health Organization, has caused governments to react swiftly with a variety of measures to quell the spread of the virus. This study investigates changes in waste disposal characteristics and the relationship between the mass of biomedical waste disposed and new COVID-19 tests performed in Regina, Canada. Results suggest that between May and September 2020, significant differences in the median amount of waste disposed exist. The amount of monthly waste disposed was slightly lower to about 450-550 tonnes/month. Monthly waste data variability, however, was significantly lower. Seasonal effects on total waste disposal is observed, but is less obvious than pre-COVID time. Furthermore, the distribution of different waste fractions varies, probably due to operational and industrial characteristics. A non-linear relationship exists between the number of COVID-19 tests performed and the mass of biomedical waste disposed, perhaps due to a lagged relationship between biomedical waste generation and disposal.


Assuntos
Eliminação de Resíduos , Canadá , Cidades , Humanos , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
15.
Ecotoxicol Environ Saf ; 211: 111913, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33493721

RESUMO

Effective management of municipal solid waste (MSW) is essential for the conservation of ecosystems in the Qinghai-Tibetan Plateau (QTP). Considering the landfill is the major method of MSW management, the factors influencing groundwater contamination near MSW landfill sites in the QTP were studied, based on field investigations, environmental impact assessment, and meteorological and hydrogeological analyses. Results indicated that the groundwater was contaminated heavily by nitrate (PI = 7.5), particularly in the landfill without an anti-seepage system, followed by nitrite (PI = 3.5) and heavy metals including arsenic (PI = 4.1) and hexavalent chromium (PI = 2.8). Total hardness, total dissolved solids, nitrate, and lead in the groundwater near the investigated landfill sites were significantly different between the monsoon and the cold seasons. Both the rainfall infiltration and the leachate infiltration were considerably limited by environmental characteristics in the QTP, including high evaporation, low rainfall, and the presence of permafrost. Soil sample contamination near landfill sites was considered as moderate (28.6% of the soil samples) and moderate to heavy (71.4% of the soil samples), based on the geoaccumulation index of mercury. However, comparatively low generation and concentrations of leachate and good topsoil quality (PI = 0.84) reduced the quantity of pollutants infiltrating into the groundwater. The alkaline leachate (pH = 7.45-9.23) and soil (pH = 7.08-8.72) also considerably decreased the concentrations of contaminants dissolved in the infiltrated rainfall and leachate. Additionally, low groundwater level can delay preferential flow and enhance attenuation. Therefore, the groundwater contamination near the landfill sites was simply point pollution, which was influenced by leachate, soil, climate, and hydrogeology characteristics in the QTP. The anti-seepage system is a potential strategy for use in the prevention of groundwater contamination by MSW landfills in the QTP.


Assuntos
Monitoramento Ambiental , Água Subterrânea/química , Instalações de Eliminação de Resíduos , Poluentes Químicos da Água/análise , Ecossistema , Água Subterrânea/análise , Metais Pesados/análise , Nitratos/análise , Eliminação de Resíduos/métodos , Estações do Ano , Solo , Resíduos Sólidos/análise , Tibet , Gerenciamento de Resíduos
16.
Waste Manag ; 121: 412-421, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33445114

RESUMO

Municipal solid waste incineration fly ash (MSWI-FA) has been regulated as a hazardous waste that needs to treat with stabilization, solidification and landfill due to its amount of heavy metals, chlorides, sulfates and dioxin. While the proper treated MSWI-FA can be utilized as pozzolanic material to reduce the usage of Portland cement. The present article aims to develop an integrated wet-extraction and carbonation process for MSWI-FA stabilization, solidification and utilization via the high-gravity technology. A benchtop experiment demonstrated the dechlorination and CO2 sequestration of MSWI-FA and the carbonated product was applied as a supplementary cementitious material (SCM) in the cement mortar. Physical, chemical and thermal characteristics of raw, wet-extracted, and carbonated MSWI-FA were addressed in terms of the mean diameter, micropore area, micropore volume, chemical compositions, mineralogy and morphology. The effects of the liquid-to-solid ratio and high gravity factor were evaluated. Overall, a chloride extraction ratio of 36.35% and a CO2 capture capacity of 258.5 g-CO2 kg-FA-1 were achieved in the batch experiment. The results of water-energy consumption of chloride removal and CO2 fixation provided a novel insight into the future process criterion. In addition, the carbonated FA was found as binder to partially substitute Portland cement due to its large content of calcium carbonate. The workability and mechanical strength of cement mortar with partial substitution of stabilized FA were evaluated to determine the potential FA utilization pathway. Finally, the continuous process tests determined the key operation indexes for future process scale-up.


Assuntos
Hipergravidade , Metais Pesados , Eliminação de Resíduos , Carbono , Dióxido de Carbono , Cinza de Carvão , Incineração , Metais Pesados/análise , Material Particulado , Resíduos Sólidos/análise
17.
Waste Manag ; 121: 441-451, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33450650

RESUMO

Proper management of urban waste might support sustainable and circular development, while mismanagement increases both costs and socio-environmental negative outcomes. In particular, the organic fraction constitutes the largest share of urban waste. In the circular economy framework, it is described as a valuable resource, to be converted into soil improver, biogas and energy. The aim of the paper is to propose a Decision Support System (DSS) for policymakers, based on linear programming techniques. This model is expected to improve the current methodologies for planning and managing organic fraction of municipal solid waste and provide useful insights about public resources allocation. The proposed optimization model is tested on Campania Region (Italy), which is a clear example of the negative implications of improper waste management. Based on the goals recently set by Campania regional government, the model allows to select the most cost-effective and sustainable solutions for treating organic waste. Results show three different scenarios associated to the impacts that each possible outcome has on the stated objectives. The "Ideal Solution" is not achievable, but it is used as a benchmark; the "Max NPV Solution" is feasible, but it reports several major drawbacks. Finally, the "Best Compromise Solution" allows to increase regional composting capability by six time and biogas availability by seven times, with environmental implications that are very similar to the ideal ones.


Assuntos
Compostagem , Eliminação de Resíduos , Gerenciamento de Resíduos , Itália , Resíduos Sólidos/análise
18.
Waste Manag ; 122: 100-112, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33508530

RESUMO

Waste disposal technology selection is a key problem in the field of municipal solid waste (MSW). This decision may have long-term impacts on environmental development and economic growth. The literature suggests using multi-criteria decision-making (MCDM) methods to address this problem. MCDM techniques commonly require decision makers to assign weightings of importance to the decision criteria based on which, the available technologies are ranked. However, this technology selection problem is concerned with selecting a technology to be used for a relatively long period of time. It is important to take into consideration any uncertainty the decision maker may have with regard to the weightings of the criteria in the future. To take this uncertainty into consideration, this study suggests utilizing a recently developed MCDM technique, namely the stratified MCDM. This technique is designed to help decision makers structure the uncertain future through the consideration of a set of states, which are placed in different strata. The paper shows how the stratified MCDM technique in combination with the best-worst method (labelled stratified BWM) can be employed to compute the ranking of the available technologies. This research is expected to stimulate future applications of the stratified BWM to facilitate long-term decision making.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Tomada de Decisões , Técnicas de Apoio para a Decisão , Resíduos Sólidos/análise , Tecnologia , Incerteza
19.
Mar Pollut Bull ; 163: 111986, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33461078

RESUMO

Small-sized plastic debris (micro- and mesoplastics) are emerging pollutants and widely detected in aquatic environments. However, micro- and mesoplastics pollution research with regard to landfills is limited. In this study, the occurrence, characteristics, and possible release of micro- and mesoplastic waste from the Galuga landfill leachate to the aquatic environment were studied. Micro- and mesoplastics were identified in all surface water samples from leachate influent and effluent of Galuga landfills. The average daily release to the aquatic environment was estimated at 80,640 ± 604.80 microplastic and 618,240 ± 1905.45 mesoplastic particles, respectively. The amount of microplastic increased three-fold and nine-fold for mesoplastics after input from the leachate drain. Micro- and mesoplastic main chemical compositions were polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyester, and cellophane. This study implied that the leachate may cause micro and mesoplastic contamination to the aquatic environment. The results raised the knowledge of small-sized plastic debris in aquatic environments.


Assuntos
Eliminação de Resíduos , Poluentes Químicos da Água , Indonésia , Microplásticos , Plásticos , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos , Poluentes Químicos da Água/análise
20.
Bioresour Technol ; 325: 124706, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33485081

RESUMO

This study examined the environmental impacts and energy consumption of three solid digestate treatment scenarios to quantify their impacts on the entire food waste (FW)-based biogas system: (1) incineration; (2) composting, and; (3) landfill. The results showed that composting had the largest net energy consumption, but least total environmental impact of 57.3 kWh and 8.75 E-03, respectively, whereas landfill showed the opposite pattern. Moreover, there were significant differences (p < 0.05) and relatively high contributions between the digestate treatment subunits among the three scenarios. The most significant contributions of digestate subunits in methods 1-3 to the 100-year global warming potential (GWP100) were 70.5%, 52.5%, and 103.4%, respectively. The results indicated that solid digestate treatment had a significant impact, and reasonable disposal of solid digestate could significantly reduce the environmental impacts and energy consumption of the entire FW-based biogas system.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Biocombustíveis , Meio Ambiente , Alimentos , Resíduos Sólidos/análise
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