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1.
Bull Environ Contam Toxicol ; 112(6): 81, 2024 Jun 01.
Article En | MEDLINE | ID: mdl-38822856

The growing production of urban solid waste is a structural problem faced by most cities around the world. The proliferation of mini-open dumps (MOD; small spontaneous open-air waste dumps formed in urban and peri-urban areas) on the banks of the Paraná River is particularly evident. During the historical drought (June-December 2021), we carried out sampling campaigns identifying MODs of the Santa Fe River, a secondary channel of the Paraná River. MOD were geolocated, measured, described and classified by origin. The distance to the river and other sensitive places was considered (houses-schools-health facilities). Our results suggested a serious environmental issue associated with poor waste management. MOD were extremely abundant in the study area, being mostly composed of domestic litter. Plastics clearly dominated the MOD composition. Burning was frequently observed as a method to reduce the volume of MOD. We concluded that the proliferation of MOD is a multi-causal problem associated with a failure of public policies and a lack of environmental education.


Environmental Monitoring , Rivers , Rivers/chemistry , Environmental Monitoring/methods , Waste Disposal Facilities , Brazil , Waste Management/methods , Cities , Refuse Disposal , Water Pollutants, Chemical/analysis , Solid Waste/analysis
3.
Environ Monit Assess ; 196(6): 537, 2024 May 10.
Article En | MEDLINE | ID: mdl-38730190

Selecting an optimal solid waste disposal site is one of the decisive waste management issues because unsuitable sites cause serious environmental and public health problems. In Kenitra province, northwest Morocco, sustainable disposal sites have become a major challenge due to rapid urbanization and population growth. In addition, the existing disposal sites are traditional and inappropriate. The objective of this study is to suggest potential suitable disposal sites using fuzzy logic and analytical hierarchy process (fuzzy-AHP) method integrated with geographic information system (GIS) techniques. For this purpose, thirteen factors affecting the selection process were involved. The results showed that 5% of the studied area is considered extremely suitable and scattered in the central-eastern parts, while 9% is considered almost unsuitable and distributed in the northern and southern parts. Thereafter, these results were validated using the area under the curve (AUC) of the receiver operating characteristics (ROC). The AUC found was 57.1%, which is a moderate prediction's accuracy because the existing sites used in the validation's process were randomly selected. These results can assist relevant authorities and stakeholders for setting new solid waste disposal sites in Kenitra province.


Fuzzy Logic , Geographic Information Systems , Refuse Disposal , Morocco , Refuse Disposal/methods , Solid Waste/analysis , Environmental Monitoring/methods , Waste Disposal Facilities , Waste Management/methods
4.
Proc Natl Acad Sci U S A ; 121(23): e2319712121, 2024 Jun 04.
Article En | MEDLINE | ID: mdl-38805276

Improving urban air quality is a pressing challenge in the Global South. A key source of air pollution is the informal burning of household waste. Reducing informal burning requires governments to develop formal systems for waste disposal and for residents to adopt new disposal behaviors. Using a randomized experiment, we show that social competitions between pairs of neighborhoods in Nansana municipality, Uganda, galvanized leadership and inspired collective action to reduce informal burning. All 44 neighborhoods in the study received a public health campaign, while 22 treated neighborhoods were paired and competed to reduce waste burning over an 8-mo period. Treated neighborhoods showed a 24 percent reduction (95% CI: 11 to 35 percent) in waste burning relative to control neighborhoods at the end of the competition period. There is no evidence that treated neighborhoods experienced a rebound in waste burning several months after the competitions. Community leaders reported greater effort in coordinating residents and more pride in their neighborhood when assigned to the competition treatment. These results suggest that creating focal points for leadership and collective action can be an effective and low-cost strategy to address policy problems that require broad participation and costly behavior change.


Air Pollution , Uganda , Humans , Air Pollution/prevention & control , Refuse Disposal/methods , Leadership
5.
Environ Monit Assess ; 196(6): 544, 2024 May 14.
Article En | MEDLINE | ID: mdl-38740657

A comprehensive analysis of municipal solid plastic waste (MSPW) management while emphasizing plastic pollution severity in coastal cities around the world is mandatory to alleviate the augmenting plastic waste footprint in nature. Thus, decision-makers' persuasion for numerous management solutions of MSPW flow-control can be met through meditative systematic strategies at the regional level. To forecast solutions focused on systematic policies, an agent-based system dynamics (ASD) model has been developed and simulated from 2023 to 2040 while considering significant knit parameters for MSPW management of Khulna City in Bangladesh. Baseline simulation results show that per-capita plastic waste generation will increase to 11.6 kg by 2040 from 8.92 kg in 2023. Eventually, the landfilled quantity of plastic waste has accumulated to 70,000 tons within 18 years. Moreover, the riverine discharge has increased to 834 tons in 2040 from a baseline quantity of 512 tons in 2023. So the plastic waste footprint index (PWFI) value rises to 24 by 2040. Furthermore, the absence of technological initiatives is responsible for the logarithmic rise of non-recyclable plastic waste to 1.35*1000=1350 tons. Finally, two consecutive policy scenarios with baseline factors such as controlled riverine discharge, increased collection and separation of plastic waste, expansion of recycle business, and locally achievable plastic conversion technologies have been simulated. Therefore, policy 2, with 69% conversion, 80% source separation, and 50% riverine discharge reduction of MSPW, has been found adequate from a sustainability perspective with the lowest PWFI ranges of 3.97 to 1.07 alongside a per-capita MSPW generation of 7.63 to 10 kg from 2023 till 2040.


Cities , Plastics , Solid Waste , Waste Management , Bangladesh , Plastics/analysis , Solid Waste/analysis , Solid Waste/statistics & numerical data , Waste Management/methods , Refuse Disposal/methods , Forecasting , Environmental Policy , Environmental Monitoring/methods , Recycling
6.
PLoS One ; 19(5): e0303754, 2024.
Article En | MEDLINE | ID: mdl-38753650

INTRODUCTION: Improved sanitation refers to those that effectively avoid human contact with excreta in a hygienic manner. Having improved latrines is a key factor in adopting safe ways of disposing of child feces. However, previous studies in Africa that examined how owning improved latrine facilities associated with household child feces disposal practices has shown inconsistent results, and no systematic review of these findings has been done. Therefore, this study aims to synthesize the evidence on the significance of households having improved latrine facilities for safe child feces disposal practices among households with under five-year-old children in Africa. METHODS: The searched databases include: PubMed/Medline, Ovid/Embase, ScienceDirect, AJOL and the Cochrane Library. In the search process, Google Scholar and references of other studies were considered. This review included studies that were published in English without any time restrictions. The outcome of this study was an estimate of the association between the ownership of an improved latrine and the disposal practices of children's feces. Two reviewers used the Excel data extraction tool to extract the relevant data from the studies that were included in the review. Using Stata version 16, a meta-analysis was performed with a random effects statistical model. The inverse index of variance (I2) was used to assess heterogeneity. Forest plots were used to show the pooled estimate with a 95% confidence interval. Publication bias was assessed using Egger's test and a funnel plot. RESULTS: Out of the 616 studies that were retrieved, 15 were included in the systematic review analysis and 10 were included in the meta-analysis. All studies that were included are cross-sectional studies done in Ethiopia, Nigeria, Gambia, Malawi, Eswatini, Ghana, Zambia, and a study used data from sub-Saharan Africa. Improved latrine facilities significantly enhanced the practice of safe child feces disposal, as shown by the overall effect size (OR = 2.74; 95% CI = 1.24-1.35, I2 = 99.95%). In the subgroup analysis by sample size, the presence of improved latrines significantly enhanced safe child feces disposal in studies with sample sizes less than 1000 (OR = 3.24; 95% CI = 2.86-3.62, I2 = 61.38%), while there was no significant difference in studies with sample sizes greater than 1000 (OR = 2.67; 95% CI = 0.69-4.64, I2 = 99.97%). However, studies that involved children under 5 years old indicated that improved latrine facilities significantly enhanced the practice of safe child feces disposal (OR = 4.02; 95% CI = 2.03-6.09; I2 = 99.96%). CONCLUSIONS: In this research study, we examined the ownership of improved latrine facilities among households with five-year-old children to enhance the disposal of child feces in a safer manner in Africa. The high heterogeneity among the studies and the cross-sectional design of the included studies limit the causal inference and generalizability of the findings. Therefore, meta-analyses of longitudinal and experimental studies are needed to confirm the causal relationship between improved latrine facilities and safe child feces disposal practices in Africa.


Feces , Toilet Facilities , Toilet Facilities/standards , Humans , Feces/chemistry , Africa , Child, Preschool , Refuse Disposal/methods , Sanitation/methods , Sanitation/standards , Child , Ownership
7.
PLoS One ; 19(5): e0303272, 2024.
Article En | MEDLINE | ID: mdl-38758824

This study presents an analysis of soil contamination caused by Ni, Zn, Cd, Cu, and Pb at municipal solid waste (MSW) landfills, with a focus on ecological risk assessment. The approach aims to assess how different landfill practices and environmental conditions affect soil contamination with potentially toxic elements (PTEs) and associated environmental risks. Soil samples were collected from MSW landfills in Poland and the Czech Republic. The research included a comprehensive assessment of PTEs in soils in the context of global environmental regulations. The degree of soil contamination by PTEs was assessed using indices: Geoaccumulation Index (Igeo), Single Pollution Index (Pi), Nemerow Pollution Index (PN), and Load Capacity of a Pollutant (PLI). The ecological risk was determined using the Risk of PTEs (ERi) and Sum of Individual Potential Risk Factors (ERI). The maximum values of the indicators observed for the Radiowo landfill were as follows: Igeo = 4.04 for Cd, Pi = 24.80 for Cd, PN = 18.22 for Cd, PLI = 2.66, ERi = 744 for Cd, ERI = 771.80. The maximum values of the indicators observed for the Zdounky landfill were as follows: Igeo = 1.04 for Cu, Pi = 3.10 for Cu, PN = 2.52 for Cu, PLI = 0.27, ERi = 25 for Cd, ERI = 41.86. The soils of the tested landfills were considered to be non-saline, with electrical conductivity (EC) values less than 2,000 µS/cm. Varying levels of PTEs were observed, and geostatistical analysis highlighted hotspots indicating pollution sources. Elevated concentrations of Cd in the soil indicated potential ecological risks. Concentrations of Cu and lead Pb were well below the thresholds set by the environmental legislation in several countries. In addition, Ni concentrations in the soils of both landfills indicated that the average levels were within acceptable limits. Principal Component Analysis (PCA) revealed common sources of PTEs. The identification of specific risk points at the Radiowo and Zdounky sites contributes to a better understanding of potential hazards in landfill environments. By establishing buffer zones and implementing regular maintenance programs, emerging environmental problems can be addressed in a timely manner.


Soil Pollutants , Waste Disposal Facilities , Soil Pollutants/analysis , Soil Pollutants/toxicity , Risk Assessment , Czech Republic , Poland , Environmental Monitoring/methods , Metals, Heavy/analysis , Metals, Heavy/toxicity , Refuse Disposal , Soil/chemistry , Solid Waste/analysis
8.
Environ Monit Assess ; 196(6): 584, 2024 May 29.
Article En | MEDLINE | ID: mdl-38809463

Despite the inherent risks associated with waste scavenging, it is surprising to note the age group involved in this activity. This study aimed to assess the motivating factors driving teenagers and youths to participate in waste scavenging, using a sample of 247 scavengers. The data underwent analysis using frequency counts, percentages, and factor analysis techniques. The findings revealed that all respondents were male and aged between 12 and 45 years. The primary sources of waste were dumpsites (61%), roadsides, and gutters (26%). Participants predominantly cited lack of formal education requirements and financial gain (93%) as key motivators for their involvement in waste scavenging. Additionally, 96% of scavengers were from northern Nigeria, with the remaining 4% from southern Nigeria. The factor analysis yielded significant results with a Kaiser-Meyer-Olkin (KMO) measure and Bartlett's test value of 67.770%, significant at p < 0.05. Four distinct factors emerged as significant motivators: (i) Lack of formal education (31.784%), (ii) Financial incentives (22.912%), (iii) Availability of wastes (14.297%), and (iv) Industrial demand for wastes (13.495%), in descending order of influence. Together, these factors accounted for 82.487% of the motivating factors behind youth engagement in waste scavenging in the study area. This outcome highlights potential challenges for the prospects of young individuals involved in scavenging unless substantial interventions are implemented. It is recommended that policies be developed to discourage scavenging activities while simultaneously promoting access to education and social welfare for this demographic. Such initiatives are crucial for redirecting young people away from scavenging and toward more sustainable livelihood options, ensuring a brighter future for them and contributing to overall societal development.


Cities , Nigeria , Humans , Adolescent , Male , Adult , Young Adult , Child , Middle Aged , Waste Management/methods , Recycling , Refuse Disposal
9.
BMC Public Health ; 24(1): 1303, 2024 May 13.
Article En | MEDLINE | ID: mdl-38741105

BACKGROUND: Unused pharmaceuticals are currently a public health problem. This study aimed to identify unused pharmaceuticals, research practices about the disposal methods, classify the medicines according to Anatomical Therapeutic Chemical codes (ATC) and, to determine the number of unused medicines. METHODS: The study was designed as a cross-sectional study. Data were collected between April and August 2023 in Burdur-Türkiye by non-probability sampling technique (convenience method). Pharmaceuticals were classified according to ATC. Statistical Package for Social Science SPSS (V.24) package program was used for data analysis. RESULTS: A total of 1120 people, 1005 in the first sample group and 115 in the second sample group, participated in the study. Findings of first sample group: A total of 4097 boxes of unused pharmaceuticals (4.7 ± 4.3 boxes/per capita) were detected. It was found that pharmaceuticals were stored in areas such as kitchens (59.1%) and refrigerators (38.6%), the reason for keeping them was reuse (41%), and the disposal practice was household garbage (81%). Paracetamol (648 boxes), Other cold preparation (303 boxes), Dexketoprofen (239 boxes), Diclofenac (218 boxes), Amoxicillin and beta-lactamase inhibitor (190 boxes) were found to be the most frequently unused pharmaceuticals. Using the unused medicines at home without consulting a physician was 94.1% (self-medication). Findings of second sample group: Of the 6189 dosage forms in 265 boxes pharmaceutical, 3132(50.6%) dosage forms were used and 3057(49.4%) were found to be unused. CONCLUSION: There is a significant amount and number of unused medicines in households, and self-medication is common. Medicines are not properly disposed of and some of them expire. Public information is needed. A "drug take-back system" for unused medicines can be useful in solving this problem.


Refuse Disposal , Cross-Sectional Studies , Humans , Adult , Pharmaceutical Preparations , Female , Male , Middle Aged , Turkey , Young Adult , Refuse Disposal/statistics & numerical data , Adolescent , Drug Storage/statistics & numerical data
10.
Waste Manag ; 183: 260-270, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38776828

The landfill is one of the most important sources of microplastics (MPs). The pretreatment method is a precondition of microplastics study for the presence of complex substances in landfills. Therefore, it is essential to examine the impact of different pretreatment methods on the microplastics detection. A literature review and a comparison experiment on digestion solutions were performed to establish a comprehensive identification method for MPs in landfills. When exposed to of 30 % H2O2, minimal mass reduction of PE, PP and PET were 4.00 %, 3.00 % and 3.00 % respectively, and the least surface damage was observed in MPs, while exhibiting the most optimal peak value for infrared spectral characteristics. It is demonstrated that the effect of 30 % H2O2 dissolution was superior compared to 10 % KOH and 65 % HNO3. The method was subsequently utilized to investigate the distribution of MPs in a landfill. The dominant MPs were polyethylene (PE, 18.56-23.91 %), polyethylene terephthalate (PET, 8.80-18.66 %), polystyrene (PS, 10.31-18.09 %), and polypropylene (PP, 11.60-14.91 %). The comprehensive identification method of "NaCl density separation + 30 % H2O2 digestion + NaI density separation + sampling microscope + Mirco-FTIR" is suitable for the detection of MPs in landfills.


Solid Waste , Waste Disposal Facilities , Refuse Disposal/methods , Polyethylene/analysis , Polyethylene Terephthalates/analysis , Polystyrenes/analysis , Polypropylenes/analysis
11.
Waste Manag ; 183: 53-62, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38718627

Advanced thermochemical technologies for plastic waste valorization represent an interesting alternative to waste-to-energy options. They are particularly appealing for waste-to-hydrogen and waste-to-chemicals applications, with autothermal steam-oxygen gasification in fluidized bed reactors showing the greatest market potential. The study describes a series of experimental tests carried out on a large pilot-scale fluidized bed gasifier, using steam and O2-enriched air, with increasing fractions of oxygen. Different values of the main operating parameters are varied: equivalence ratio (0.22-0.25), steam-to-carbon ratio (0.7-1.13), and steam-to-oxygen ratio (up to 3.2). The fuel consists of real mixed plastic waste coming from separate collection of municipal solid wastes. The data obtained are used to investigate in depth the role of the main operating parameters and to improve and validate a recently developed one-dimensional kinetic model for waste gasification. The validation shows a good agreement between experimental data and model results, suggesting the reliability of the model to predict the reactor behavior under conditions of pure steam-oxygen gasification, relevant to many industrial applications. It has been found that the equivalence ratio is the parameter that most affects the syngas composition. At a constant equivalent ratio, the molar fraction of oxygen in the enriched air shows a limited influence on syngas composition while the steam is crucial in controlling the temperature along the reactor. Provided that the steam-to-carbon molar ratio is larger than 1.5, steam affects mainly the reactor temperature rather than the syngas composition, qualifying the steam-to-oxygen molar ratio as an instrumental parameter for smooth plant operation.


Oxygen , Plastics , Refuse Disposal , Steam , Oxygen/analysis , Refuse Disposal/methods , Pilot Projects , Solid Waste/analysis , Models, Theoretical , Gases/analysis
12.
Waste Manag ; 183: 63-73, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38718628

With the recent advancement in artificial intelligence, there are new opportunities to adopt smart technologies for the sorting of materials at the beginning of the recycling value chain. An automatic bin capable of sorting the waste among paper, plastic, glass & aluminium, and residual waste was installed in public areas of Milan Malpensa airport, a context where the separate collection is challenging. First, the airport waste composition was assessed, together with the efficiency of the manual sorting performed by passengers among the conventional bins: paper, plastic, glass & aluminium, and residual waste. Then, the environmental (via the life cycle assessment - LCA) and the economic performances of the current system were compared to those of a system in which the sorting is performed by the automatic bin. Three scenarios were evaluated: i) all waste from public areas, despite being separately collected, is sent to incineration with energy recovery, due to the inadequate separation quality (S0); ii) recyclable fractions are sent to recycling according to the actual level of impurities in the bags (S0R); iii) fractions are sorted by the automatic bin and sent to recycling (S1). According to the results, the current separate collection shows a 62 % classification accuracy. Focusing on LCA, S0 causes an additional burden of 12.4 mPt (milli points) per tonne of waste. By contrast, S0R shows a benefit (-26.4 mPt/t) and S1 allows for a further 33 % increase of benefits. Moreover, the cost analysis indicates potential savings of 24.3 €/t in S1, when compared to S0.


Airports , Recycling , Refuse Disposal , Solid Waste , Recycling/methods , Recycling/economics , Solid Waste/analysis , Refuse Disposal/methods , Refuse Disposal/economics , Italy , Costs and Cost Analysis , Waste Management/methods , Waste Management/economics , Automation , Incineration/methods , Incineration/economics
14.
Waste Manag ; 183: 101-111, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38735093

The permeability of municipal solid wastes (MSWs) is important for the design and operation of landfills. This study presented the experimental investigation of the permeability of low food content- (LF-) and high food content- (HF-) MSWs prepared in laboratory-scale bioreactors for up to 5 years. The permeability of MSWs with diverse degrees of decomposition (DOBs), void ratios, and permeation liquids was measured (288 tests). The measured permeability was compared to that predicted from the (modified) Kozeny-Carman (K-C) equations in four different forms. The results indicated that the permeability of both LF- and HF-MSWs decreased significantly (p < 0.05) with decomposition under a given void ratio. The predicted permeability using the original K-C equation fitted well with that of fresh MSWs. The permeability of decomposed MSWs was closer to the predicted results using the modified K-C equation with the effective void ratio. This can be attributed to the increase in the fine fractions due to degradation. The reduction in the effective voids was more significant with HF-MSWs. The parameters required in the (modified) K-C equations showed a good correlation with DOB and effective particle size (d10). The predicted permeability based on the relationship between DOB (or d10) and equation parameters was within 3 times the difference compared to the measured values. The above results indicated that the modified K-C equation can be adopted to predict the permeability of fresh and degraded MSWs while more field-scale experiments should be conducted to further evaluate its feasibility.


Permeability , Refuse Disposal , Solid Waste , Solid Waste/analysis , Refuse Disposal/methods , Food , Bioreactors , Waste Disposal Facilities
15.
Waste Manag ; 183: 87-100, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38735094

This research paper focuses on effective infectious municipal waste management in urban settings, highlighting a dearth of dedicated research in this domain. Unlike general or specific waste types, infectious waste poses distinct health and environmental risks. Leveraging advanced artificial intelligence techniques, we prioritize infectious waste categorization and optimization, integrating metaheuristics into optimization methods to create a robust dual-ensemble framework. Our model, the "Enhanced Artificial Intelligence for Infectious Municipal Waste Classification System," combines ensemble image segmentation methods and diverse convolutional neural network models. Innovative geometric image augmentation enhances model robustness, diversifies training data, and improves accuracy across waste types. A pivotal aspect is the integration of a reinforcement learning-differential evolution algorithm as a decision fusion strategy, optimizing classification by harmonizing outputs from ensemble methods and convolutional neural network models. Computational results, using a newly collected dataset, demonstrate our model's accuracy exceeding 96.54% while using the existing solid waste dataset we achieve the accuracy of 97.81%, outperforming advanced approaches by margins ranging from 2.02% to 8.80%. This research significantly advances sustainable waste management, showcasing artificial intelligence's transformative potential in addressing intricate waste challenges. It establishes a foundational framework prioritizing efficiency, effectiveness, and sustainability for future waste management solutions. Acknowledging the importance of diverse datasets, customization for urban contexts, and practical integration into existing infrastructures, our work contributes to the broader discourse on the role of artificial intelligence in evolving waste management practices.


Artificial Intelligence , Neural Networks, Computer , Waste Management , Waste Management/methods , Solid Waste/analysis , Algorithms , Cities , Refuse Disposal/methods
16.
Waste Manag ; 183: 112-122, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38739988

Pyrolysis has emerged as a promising technology for valorizing digestate resulting from the anaerobic digestion of food waste. However, the high NOX emissions during pyrolysis limit its application. This study proposed a hydrothermal coupled pyrolysis process to control the element transfer in digestate during biochar production. The efficient reduction of NOX emissions and the improvement of biochar adsorbability were realized. The hydrothermal process reduced the nitrogen content in solid digestate by 49.10 %-81.79 %, thus reducing the NOX precursors in syngas and the N-containing substances in bio-oil. Additionally, the specific surface area and the total pore volume of biochar were enhanced from 25 m2/g to 60-73 m2/g and 0.06 cm3/g to 0.12-0.14 cm3/g, respectively. More defects, oxygen-containing functional groups, and doped Ca on the biochar resulted in a high phosphate removal efficiency of 94 %. The proposed technology provides an efficient and environmentally friendly way to utilize the digestate.


Charcoal , Pyrolysis , Charcoal/chemistry , Nitrogen Oxides/chemistry , Nitrogen Oxides/analysis , Food , Refuse Disposal/methods , Nitrogen/chemistry , Food Loss and Waste
17.
Waste Manag ; 183: 153-162, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38754183

Corruption is known to be one of the real life situations which may jeopardize the effectiveness of fines in deterring crime. We present a model of 'crime with corruption' by which both the dilution of crime deterrence due to corruption, as well as the possibility of crime encouraging fines, are formally highlighted. More importantly, by running an experiment on a subject pool of students for the case of illegal waste disposal, we provide experimental evidence on the validity of our theoretical predictions. We find that increasing fine rate may become crime encouraging, or at least ineffective, beyond a context-specific fine threshold. From a policy perspective, we suggest that the optimal design of a crime-deterring sanctioning system must simultaneously account for both corruption practices and anti-corruption policies.


Crime , Refuse Disposal , Refuse Disposal/methods , Waste Management/methods , Models, Theoretical , Humans
18.
Waste Manag ; 183: 184-190, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38759276

Municipal solid waste incineration (MSWI) fly ash is a hazardous waste containing heavy metals. Secondary aluminum dross (SAD) is a hazardous waste discharged from aluminum smelting, containing active aluminum nitride (AlN). In this work, heavy metals from MSWI fly ash were reduced into alloy by AlN from SAD, and the slag was manufactured into transparent glass for building. Reduction of iron and zinc was 67 and 100 %, respectively. Reduction mechanism was explored after applying XRD, XRF and thermodynamics analysis. It was found that the reduction reaction was an ion reaction. The AlN and heavy metal oxide transformed into anionic group containing nitrogen and heavy metal cation, after entering slag. The heavy metals were reduced into alloy after electron was transferred from anionic group to cation. In addition, the reduced iron and zinc could merge into alloy, which inhibited evaporation of zinc. Yellow transparent glass was obtained after the reduction process. Yellow was come from titanium oxide, which could not be reduced by AlN. Microhardness, density and water absorption of the transparent glass were 741 HV, 2.86 g·cm-3 and 0.04 %, respectively. Leaching content of Ni, Cu, Zn and Pb of the glass were 0.1, <0.1, 0.6 and < 0.1 mg/L, respectively, all below the TCLP limit. About 115 âˆ¼ 213 dollars were earned after manufacturing 500 kg of MSWI fly ash into transparent glass. This work provided a novel idea of recycling solid waste into alloy and transparent glass for building.


Coal Ash , Glass , Incineration , Metals, Heavy , Solid Waste , Coal Ash/chemistry , Incineration/methods , Metals, Heavy/chemistry , Metals, Heavy/analysis , Solid Waste/analysis , Glass/chemistry , Refuse Disposal/methods
19.
Waste Manag ; 183: 174-183, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38759275

Solid-phase residues from pyrolysis of oily wastes (OS) are widely used due to their rich pore structure and strong adsorption capacity. In this study, pyrolysis residues (OS-P) were obtained from the pyrolysis treatment of four typical OS in Karamay, Xinjiang. The results indicate that the crystalline substances in OS-P mainly were SiO2, BaSO4, and graphite. The heavy metals of OS-P were higher than that of OS in the following order: Zn > Cu > Ni > Cr > Pb > Cd. The results of the improvement of Community Bureau of Reference (BCR) sequential extraction showed that the proportion of Cu, Ni and Cr in OS1-P in the residual fraction was higher than that of the other three OS. The residual fraction of Cu, Ni, and Cr in OS1-P increased from 16.0 %, 30.0 %, and 11.0 % to 66.1 %, 81.9 %, and 89.2 %, respectively. After pyrolysis treatment, the leaching concentration of heavy metals in the residue was reduced. Referring to the requirements for heavy metal control limits (GB 4284-2018), all heavy metals in OS-P showed low risk. Their potential ecological risk indices were 4.11, 3.13, 4.87 and 5.35, respectively, indicating that the potential ecological hazards of heavy metals from OS-P were slight. There was no significant effect on the histopathological changes of kidney, lung, liver, ovary and testis of mice, showing that the rational use of OS-P in production will not produce toxic effects on target animals. Based on risk assessment and safety evaluation, the application of OS-P is controllable, safe and reliable for resource utilization.


Metals, Heavy , Pyrolysis , Metals, Heavy/analysis , Risk Assessment/methods , Animals , Mice , China , Refuse Disposal/methods
20.
Waste Manag ; 183: 220-231, 2024 Jun 30.
Article En | MEDLINE | ID: mdl-38761486

Cities face the challenges of supplying food and managing organic municipal solid waste (OMSW) sustainably amid increasing urbanization rates. Urban agriculture (UA) can help with this effort by producing local crops that are fertilized with nutrients recovered from compost generated from OMSW. This research aims to determine the potential of OMSW compost to supply the nitrogen-phosphorus-potassium (NPK) demand of UA and the environmental benefits of replacing mineral fertilizer from a life cycle perspective. The Metropolitan Area of Barcelona (AMB) serves as the case study given its commitment to reuse biowaste according to the Revised Waste Framework Directive and to promote UA as a signing member of the Milan Urban Food Policy Pact. Based on crop requirements and farmer surveys, we find that the annual NPK demands of the agricultural fields of the AMB that cover 5,500 ha and produce 70,000 tons of crops are approximately 769, 113, and 592 tons of NPK, respectively. Spatial material flow analysis and life cycle assessment were applied to found that the current waste management system can potentially substitute 8 % of the total NPK demanded by UA with compost, reduce the impacts by up to 39 % and yield savings in global warming of 130 %. The more ambitious future scenario of 2025 can potentially substitute 21 % of the total NPK demand and reduce environmental impacts up to 1,049 %, depending on the category considered. Avoiding processing of mixed OMSW, mineral fertilizer replacement and cogeneration of electricity from biogas are the major contributors to these environmental savings.


Agriculture , Cities , Fertilizers , Solid Waste , Solid Waste/analysis , Agriculture/methods , Nitrogen/analysis , Spain , Phosphorus/analysis , Refuse Disposal/methods , Waste Management/methods , Potassium/analysis , Composting/methods
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