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

ABSTRACT

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.


Subject(s)
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
2.
Environ Monit Assess ; 196(6): 537, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38730190

ABSTRACT

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.


Subject(s)
Fuzzy Logic , Geographic Information Systems , Refuse Disposal , Morocco , Refuse Disposal/methods , Solid Waste/analysis , Environmental Monitoring/methods , Waste Disposal Facilities , Waste Management/methods
3.
Bioresour Technol ; 402: 130762, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38692371

ABSTRACT

Ionic cadmium (Cd (II)) in water is a significant threat to ecosystems, the environment, and human health. Research is currently focused on developing efficient adsorption materials to combat Cd (II) pollution in water. One promising solution involves co-pyrolyzing solid residue from anaerobic digestion of food waste with oil-based drill cuttings pyrolysis residue to create a biochar with high organic matter content. This biochar has a lower heavy metal content and leaching toxicity compared to China's national standards, making it both safe and resourceful. It exhibits a high adsorption capacity for Cd (II) in water, reaching up to 47.80 ± 0.37 mg/g. Raising the pyrolysis temperature above 600 °C and increasing the amount of pyrolysis residue beyond 30 % enhances the biochar's adsorption capacity. The adsorption process is primarily driven by mineral precipitation, offering a promising approach for dual waste resource management and reducing heavy metal pollution.


Subject(s)
Cadmium , Charcoal , Solid Waste , Cadmium/chemistry , Charcoal/chemistry , Adsorption , Pyrolysis , Water Pollutants, Chemical/chemistry , Minerals/chemistry , Chemical Precipitation , Water Purification/methods
4.
Bioresour Technol ; 402: 130766, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38692378

ABSTRACT

Compared to typical anaerobic digestion processes, little is known about both sludge microbial compositions and biogas production models for full-scale dry methane fermentation treating municipal solid waste (MSW). The anaerobic sludge composed of one major hydrogenotrophic methanogen (Methanoculleus) and syntrophic acetate oxidizing bacteria (e.g., Caldicoprobacter), besides enrichment of MSW degraders such as Clostridia. The core population remained phylogenetically unchanged during the fermentation process, regardless of amounts of MSW supplied (∼35 ton/d) or biogas produced (∼12000 Nm3/d). Based on the correlations observed between feed amounts of MSW from 6 days in advance to the current day and biogas output (the strongest correlation: r = 0.77), the best multiple linear regression (MLR) model incorporating the temperature factor was developed with a good prediction for validation data (R2 = 0.975). The proposed simple MLR method with only data on the feedstock amounts will help decision-making processes to prevent low-efficient biogas production.


Subject(s)
Biofuels , Fermentation , Methane , Sewage , Solid Waste , Methane/metabolism , Fermentation/physiology , Sewage/microbiology , Anaerobiosis , Refuse Disposal/methods , Temperature , Linear Models , Phylogeny , Bacteria/metabolism , Bioreactors
5.
Waste Manag ; 183: 260-270, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38776828

ABSTRACT

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.


Subject(s)
Solid Waste , Waste Disposal Facilities , Refuse Disposal/methods , Polyethylene/analysis , Polyethylene Terephthalates/analysis , Polystyrenes/analysis , Polypropylenes/analysis
6.
PLoS One ; 19(5): e0303272, 2024.
Article in English | MEDLINE | ID: mdl-38758824

ABSTRACT

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.


Subject(s)
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
7.
J Environ Manage ; 359: 120987, 2024 May.
Article in English | MEDLINE | ID: mdl-38692029

ABSTRACT

The removal of organic pollutants in water environments and the resource utilization of solid waste are two pressing issues around the world. Facing the increasing pollution induced by discharge of mining effluents containing sodium isopropyl xanthate (SIPX), in this work, municipal solid waste incineration fly ash (MSWI FA) was pretreated by hydrothermal method to produce stabilized FA, which was then innovatively used as support for the construction of FA/TiO2/BiOCl nanocomposite (FTB) with promoted photocatalytic activity under visible light and natural sunlight. When the content of FA was 20 wt% and the mass ratio of TiO2 to BiOCl was 4:6, a remarkable performance for the optimal FTB (20-FTB-2) was achieved. Characterizations demonstrated that TiO2 and BiOCl uniformly dispersed on FA contributing to high surface area and broad light adsorption of FTB, which exhibits excellent adsorption capacity and light response ability. Build in electric field formed in the interface of TiO2/BiOCl heterojunction revealed by density functional theory calculations accelerated the separation of photoinduced e- and h+, leading to high efficiency for SIPX degradation. The synergetic effect combined with adsorption and photocatalytic degradation endowed 20-FTB-2 superior SIPX removal efficiency over 99% within 30 min under visible light and natural sunlight irradiation. The photocatalytic degradation pathways of SIPX were determined through theoretical calculations and characterizations, and the toxic byproduct CS2 was effectively eliminated through oxidation of •O2-. For 20-FTB-2, reusability of photocatalyst was showed by cycle tests, also the concentrations of main heavy metals (Pb, Zn, Cu, Cr, and Cd) in the liquid phases released during photocatalyst preparation process (< 1 mg/L) and photodegradation process (< 8.5 µg/L) proved the satisfactory stability with low toxicity. This work proposed a novel strategy to develop efficient and stable support-based photocatalysts by utilizing MSWI FA and realize its resource utilization.


Subject(s)
Coal Ash , Nanocomposites , Titanium , Nanocomposites/chemistry , Titanium/chemistry , Coal Ash/chemistry , Catalysis , Adsorption , Solid Waste , Water Pollutants, Chemical/chemistry
8.
Chemosphere ; 359: 142276, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38761830

ABSTRACT

The production of solid wastes in the metallurgical industry has significant implications for land resources and environmental pollution. To address this issue, it is crucial to explore the potential of recycling these solid wastes to reduce land occupation while protecting the environment and promoting resource utilization. Steel slag, red mud, copper slag and steel picking waste liquor are examples of solid wastes generated during the metallurgical process that possess high iron content and Fe species, making them excellent catalysts for persulfate-based advanced oxidation processes (PS-AOPs). This review elucidates the catalytic mechanisms and pathways of Fe2+ and Fe0 in the activation PS. Additionally, it underscores the potential of metallurgical iron-containing solid waste (MISW) as a catalyst for PS activation, offering a viable strategy for its high-value utilization. Lastly, the article provides an outlook towards future challenges and prospects for MISW in PS activation for the degradation of organic pollutants.


Subject(s)
Iron , Solid Waste , Iron/chemistry , Catalysis , Oxidation-Reduction , Metallurgy , Sulfates/chemistry , Environmental Pollutants/chemistry , Recycling/methods , Environmental Pollution/prevention & control
9.
Waste Manag ; 183: 53-62, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38718627

ABSTRACT

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.


Subject(s)
Oxygen , Plastics , Refuse Disposal , Steam , Oxygen/analysis , Refuse Disposal/methods , Pilot Projects , Solid Waste/analysis , Models, Theoretical , Gases/analysis
10.
Waste Manag ; 183: 63-73, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38718628

ABSTRACT

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.


Subject(s)
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
12.
Waste Manag ; 183: 101-111, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38735093

ABSTRACT

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.


Subject(s)
Permeability , Refuse Disposal , Solid Waste , Solid Waste/analysis , Refuse Disposal/methods , Food , Bioreactors , Waste Disposal Facilities
13.
Waste Manag ; 183: 87-100, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38735094

ABSTRACT

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.


Subject(s)
Artificial Intelligence , Neural Networks, Computer , Waste Management , Waste Management/methods , Solid Waste/analysis , Algorithms , Cities , Refuse Disposal/methods
14.
Waste Manag ; 183: 184-190, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38759276

ABSTRACT

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.


Subject(s)
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
15.
Waste Manag ; 183: 220-231, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38761486

ABSTRACT

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.


Subject(s)
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
16.
Waste Manag ; 183: 191-198, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38761483

ABSTRACT

With the development of municipal solid waste incineration technologies, the disposal of fly ash has become a difficult problem that many countries need to solve. High-temperature melting is a promising disposal technology. Based on this, a new process for collaborative treatment of fly ash in metallurgical blast furnaces had been proposed in this study. To explore the impact of disposal of fly ash on blast furnace production, by simulating the high-temperature reducing environment of blast furnaces, the melting changes of water-washed fly ash (W-FA), and the effects of W-FA injection on coal combustion and products (slag, iron) composition were studied. The results showed that W-FA, as a flux, could be sprayed into the blast furnace separately or mixed with coal. But when injected along with coal, W-FA would suppress the combustion of coal. After melting, the removal rates of S, P, Cl, and Pb in W-FA were 21%, 30%, 86%, and 89%, respectively. The removal rates of K, Na, and Zn were close to 100%, and Cr was basically not removed. When the proportion of W-FA to coal was less than 1%, in addition to controlling the alkalinity of the slag, the impact of W-FA on the composition of iron and slag was minimal. The successful execution of this work will not only achieve the reduction, harmless and resourceful utilization of fly ash, but also save investment and operating costs of disposal facilities, with both environmental and social benefits.


Subject(s)
Coal Ash , Incineration , Refuse Disposal , Solid Waste , Coal Ash/chemistry , Incineration/methods , Solid Waste/analysis , Refuse Disposal/methods , Hot Temperature , Coal
17.
Waste Manag ; 183: 245-252, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-38772135

ABSTRACT

The research was aimed at providing new knowledge in the field of chemical characteristics of solid waste generated in the process of combustion of sewage sludge in fluidized bed furnaces. The research material consisted of disposed fluidized beds (DFB), sewage sludge ash (SSA) and air pollution control residues (APC) from three Polish installations for the thermal treatment of sewage sludge. Natural radionuclides as well as anthropogenic isotope 137Cs were determined in the tested materials and the migration of a wide spectrum of trace elements to various waste fractions generated in the process of sewage sludge combustion was examined. It was observed that both radioisotopes and most of the trace elements determined accumulate in SSA and DFB, while the APC fraction contains a much smaller amount of them. The exceptions are mercury and selenium, whose volatile compounds migrate to the exhaust gas dedusting system and accumulate in the APC fraction (up to 40 mg/kg and 13 mg/kg, respectively). A potential threat from the 226Ra isotope in SSA is identified in the context of the management of this waste in the production of building materials because the typical activity of 226Ra in SSA collected from areas with very low Ra content in natural environment exceeds 1.5-6 times the activity of this isotope in conventional cement mixtures. When managing SSA and DFB, special attention should be paid to the content of metalloids such as As, B and Se, due to the high content of mobile forms of these elements in the mentioned materials.


Subject(s)
Incineration , Sewage , Solid Waste , Trace Elements , Sewage/chemistry , Trace Elements/analysis , Incineration/methods , Solid Waste/analysis , Poland , Radioisotopes/analysis , Refuse Disposal/methods , Cesium Radioisotopes/analysis
18.
Sci Total Environ ; 931: 172885, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38697546

ABSTRACT

Nanobubble (NB) technology has gained popularity in the environmental field owing to its distinctive characteristics and ecological safety. More recently, the application of NB technology in anaerobic digestion (AD) systems has been proven to promote substrate degradation and boost the production of biogas (H2 and/or CH4). This review presents the recent advancements in the application of NB technology in AD systems. Meanwhile, it also sheds light on the underlying mechanisms of NB technology that contribute to the enhanced biogas production from AD of organic solid wastes. Specifically, the working principles of the NB generator are first summarized, and then the structure of the NB generator is optimized to accommodate the demand for NB characteristics in the AD system. Subsequently, it delves into a detailed discussion of how the addition of nanobubble water (NBW) affects AD performance and the different factors that NB can potentially contribute. As a simple and environmentally friendly additive, NBW was commonly used in the AD process to enhance the fluidity and mass transfer characteristics of digestate. Additionally, NB has the potential to enhance the functionality of different types of microbial enzymes that play crucial roles in the AD process. This includes boosting extracellular hydrolase activities, optimizing coenzyme F420, and improving cellulase function. Finally, it is proposed that NBW has development potential for the pretreatment of substrate and inoculum, with future development being directed towards this aim.


Subject(s)
Biofuels , Refuse Disposal , Anaerobiosis , Refuse Disposal/methods , Solid Waste , Bioreactors
19.
Environ Sci Pollut Res Int ; 31(23): 34340-34354, 2024 May.
Article in English | MEDLINE | ID: mdl-38700771

ABSTRACT

Global community is increasingly alarmed by resource depletion and environmental pollution. In light of pressing environmental concerns and depletion of finite resources, the surge in fossil fuel usage has sparked twin crises: dwindling fossil fuel reserves and escalating environmental pollution. The current study introduces a novel approach to minimize waste by transforming it into briquettes suitable for large-scale production. Production of briquettes involves multiple stages, including collection, drying, crushing, screening, blending, compacting, and storage. The main objective of this research is to demonstrate and investigate the physico-mechanical and emission properties of briquettes produced with readily available organic fraction of municipal solid waste (MSW) such as food and garden waste. The physical, mechanical, and elemental characteristics such as calorific value, moisture content, ash, volatile matter, fixed carbon, density, compressive strength, and SEM-EDAX were determined. A combustibility test along with emission and water boiling test was also carried out. The MSW briquettes were prepared in a densification system at 130 °C temperature and 20 MPa. The study's conclusion suggests that the MSW briquette with lignin content of 25-30%, calorific value of 22.53 MJ/kg, compressive strength of 14.517 N/mm2, and density of 1124.12 kg m-3 could be used to retain energy and lessen the harmful effects of climate change while also enhancing sustainability. Flue gas emissions from burning MSW briquettes in a biomass stove were examined in this study using flue gas analyzer and smoke meter. Furthermore, the generated briquettes exhibit a density of 1124.12 kg m-3 which is on par with coal, making them suitable for co-firing in boilers. Likewise, the determined parameters are compared with the biomass briquettes and firewood. Further investigation is required to elevate its quality and economic potential.


Subject(s)
Solid Waste , Sustainable Development
20.
Environ Sci Pollut Res Int ; 31(23): 34622-34646, 2024 May.
Article in English | MEDLINE | ID: mdl-38709410

ABSTRACT

A blend of organic municipal solid waste, slaughterhouse waste, fecal sludge, and landfill leachate was selected in different mixing ratios to formulate the best substrate mixture for biomethanation. Individual substrates were characterized, and the mixing ratio was optimized with the help of a response surface methodology tool to a value of 1:1:1:1 (with a C/N ratio of 28±0.769 and total volatile fatty acid (VFA) concentration of 2500±10.53 mg/L) to improve the overall biomethanation. The optimized blend (C/N ratio: 28.6, VFA: 2538 mg/L) was characterized for physicochemical, biological, and microbial properties and subjected to anaerobic digestion in lab-scale reactors of 1000 mL capacity with and without the addition of inoculum. The biogas yield of individual substrates and blends was ascertained separately. The observed cumulative biogas yield over 21 days from the non-inoculated substrates varied between 142±1.95 mL (24.6±0.3 ml/gVS) and 1974.5±21.72 mL (270.4±3.1 ml/gVS). In comparison, the addition of external inoculation at a 5% rate (w/w) of the substrate uplifted the minimum and maximum cumulative gas yield values to 203±9.9 mL (35.0±1.6 mL/gVS) and 3394±13.4 mL (315.3±1.2 mL/gVS), respectively. The inoculum procured from the Defence Research and Development Organisation (DRDO) was screened in advance, considering factors such as maximizing VFA production and consumption rate, biogas yield, and digestate quality. A similar outcome regarding biogas yield and digestate quality was observed for the equivalent blend. The cumulative gas yield increased from 2673±14.5 mL (373.7±2.2 mL/gVS) to 4284±111.02 mL (391.47±20.02 mL/gVS) over 21 days post-application of a similar dosage of DRDO inoculum. The 16S rRNA genomic analysis revealed that the predominant bacterial population belonged to the phylum Firmicutes, with the majority falling within the orders Clostridiales and Lactobacillales. Ultimately, the study advocates the potential of the blend mentioned above for biomethanation and concomitant enrichment of both biogas yield and digestate quality.


Subject(s)
Fatty Acids, Volatile , Fatty Acids, Volatile/metabolism , Solid Waste , Bioreactors , Biofuels , Methane , Sewage , Anaerobiosis
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