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1.
Environ Pollut ; 266(Pt 3): 115282, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32799176

RESUMO

The comparison of fly ash generated from lignite combustion in a thermal power plant Kolubara A (Veliki Crljeni) and bottom and fly ash from coal waste combustion in a semi-industrial fluidized bed boiler (Vinca) was performed as the function of particle size. The average total concentrations of the 16 EPA priority PAHs in ash fractions are 0.49 mg kg-1 of ash (thermal power plant) and 17.48 mg kg-1 of ash (fluidized bed boiler). The sum of 3- and 4-ring PAHs accounts for more than 93% of overall PAHs concentration, and the most abundant among them is fluoranthene. The portions of PAHs groups defined based on their physico-chemical properties, as obtained from quantitative structure-activity relationship (QSAR) models included in the Vega platform, were determined. These portions, emission factors, and benzo[a]pyrene equivalence concentrations were further on used to estimate the potential environmental impact of ash disposal. The PAHs emission factors are higher compared to values in the air pollutant emission inventory guidebook of the cooperative program for monitoring and evaluation of the long-range transmission of air pollutants in Europe (EMEP/EEA). The overall emission factors of 16 PAHs for combustion of lignite and coal waste are determined to be 0.15 and 249.97 mg kg-1 of fuel, respectively. Based on the ratios of benzo[a]pyrene equivalence concentrations of each ash and correspondent fuel, the disposal of fly ash from the cyclone of fluidized bed boiler represents the highest risk to the environment among tested ashes.


Assuntos
Cinza de Carvão/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Carvão Mineral/análise , Europa (Continente) , Incineração , Centrais Elétricas
2.
Waste Manag ; 117: 136-145, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32823078

RESUMO

Bread waste represents a significant part of food waste in Sweden. At the same time, the return system established between bakeries and retailers enables a flow of bread waste that is not contaminated with other food waste products. This provides an opportunity for alternative valorisation and waste management options, in addition to the most common municipal waste treatment, namely anaerobic digestion and incineration. An attributional life cycle assessment of the management of 1 kg of surplus bread was conducted to assess the relative environmental impacts of alternative and existing waste management options. Eighteen impact categories were assessed using the ReCiPe methodology. The different management options that were investigated for the surplus bread are donation, use as animal feed, beer production, ethanol production, anaerobic digestion, and incineration. These results are also compared to reducing the production of bread by the amount of surplus bread (reduction at the source). The results support a waste hierarchy where reduction at the source has the highest environmental savings, followed by use of surplus bread as animal feed, donation, for beer production and for ethanol production. Anaerobic digestion and incineration offer the lowest environmental savings, particularly in a low-impact energy system. The results suggests that Sweden can make use of the established return system to implement environmentally preferred options for the management of surplus bread.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Animais , Pão , Incineração , Suécia
3.
Waste Manag ; 117: 104-113, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32829004

RESUMO

In Switzerland MSWI bottom ash has to comply with the legal threshold value for TOC of < 2 wt-% in order to be landfilled. However, TOC contents of this magnitude lead to elevated DOC emissions and associated emissions of ammonium and Cu (aq). Since 2008 the Canton of Zürich therefore pursues a strategy to lower TOC contents in bottom ash by 2020 to 0.5 wt-%. To observe the development of TOC and other constituents, bottom ash has been monitored from 2008 to 2018. Monitoring results indicate that TOC contents < 0.5 wt-% in bottom ash lead to DOC eluate concentrations < 20 mg/l. DOC concentrations of this magnitude are close to Swiss legal criteria for discharge of landfill leachate into surface waters (10 mg/l). The emission results have been obtained by batch eluate tests according to Swiss Waste Legislation. Such laboratory tests only partially simulate real conditions occurring on landfills. To approximate landfill conditions, column tests with recent bottom ashes combined with tests on simple emission forecasting complete the study. The comparison of results from batch and column tests shows similar cumulative concentrations, indicating that batch tests are suitable to evaluate bottom ash quality. The tested modelling approach, based on constant conditions and exponential decrease in concentration, proved adequate to simulate column progressions. The modelled emission forecasts for DOC lies within 33% of column test results. Further, the model demonstrates the differences in flow regime between eluate tests and landfills and promotes better understanding of temporal aspects and the influence of landfill relevant parameters on pollutant mobilisation.


Assuntos
Cinza de Carvão/análise , Poluentes Ambientais , Incineração , Suíça , Instalações de Eliminação de Resíduos
4.
Environ Pollut ; 266(Pt 3): 115420, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32829031

RESUMO

In this study, the detoxification mechanisms of water-soluble fluorine in the bottom ash and the distribution of fluorine during the spent potlining (SPL) incineration were characterized in response to four calcium compounds using an experimental tube furnace. CaSiO3, CaO, Ca(OH)2, and CaCO3-assisted SPL incineration converted NaF to low toxicity compounds in the bottom ash yielding a conversion range of 54.24-99.45% relative to the individual SPL incineration. The two main mechanisms of the fluorine transformation were the formations of CaF2 and Ca4Si2O7F2. The fluorine transformation efficiency was greater with CaSiO3 than CaO, Ca(OH)2, and CaCO3. Our simulations demonstrated that SiO2 enhanced the conversion of NaF. The fluorine leaching content of the bottom ash was estimated at 13.71 mg⋅L-1 after the SPL co-incineration with CaSiO3 (Ca:F = 1.2:1). The acid-alkali solutions had no significant effect on the fluorine leaching content of the bottom ash when 3 ≤ pH ≤ 12. Fluorine during the SPL co-incineration with CaSiO3 (Ca:F = 1.2:1) at 850 °C for 60 min was partitioned into 83.37, 13.90, and 2.72% in the bottom ash, fly ash, and flue gas, respectively. The transformation and detoxification mechanisms of water-soluble fluorine provide new insights into controls on fluorine emission from the SPL incineration.


Assuntos
Flúor , Incineração , Compostos de Cálcio , Cinza de Carvão , Dióxido de Silício , Água
5.
J Environ Manage ; 271: 110884, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32778256

RESUMO

This paper focuses on the functionalization of heterogeneous and highly contaminated waste material, namely bottom ashes (BA) with a particle size ≤ 125 µm that cannot be recycled with conventional treatments. The main goal of this study is to modify this waste into a valuable material that can be used in various applications, especially in the building sector. The complex mineralogical nature of this material was investigated with quantitative XRD, which confirms the presence of crystalline and amorphous phases such as silicates, carbonates, metallic oxides and amorphous glass. A hydrophobic modification was performed by using a fluorosilane grafting agent that utilizes the reactive surface sites of these minerals to form silanol bonds. Results showed that the 2.5% (m/m) of silane made the BA hydrophobic. Moreover, a thorough characterization showed that fluorosilane was well-grafted at the surface of the BA, with more than 60% of the fluorosilane chemisorbed on the surface. Additionally, the hydrophobic modification led to a significant decrease of the leaching of the contaminants (Cr, Cu, Mo and Sb) from the BA particles. Following this methodology, fine fraction of BA could be eventually used as a building material, preventing the landfill of this toxic waste.


Assuntos
Cinza de Carvão , Incineração , Carbonatos , Materiais de Construção , Resíduos Sólidos
6.
Waste Manag ; 116: 31-39, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32784119

RESUMO

This paper presents an inventory of sewage sludge ashes (SSA) generated in the mono-incineration plants for municipal sewage sludge in Poland. This research focused on the detailed study of mass flows, chemical composition, and phosphorus recovery potential. There are currently 11 sludge mono-incineration plants operated with a total capacity of 160,300 Mg dry weight (d.w.) of sludge annually. Recently, a significant increase in the amount of SSA generated in these plants has been observed, reaching 26,756 Mg in 2018. Chemical composition of SSA showed significant amounts of the main nutrients: calcium (~14%), phosphorus (~13%), magnesium (~3%), and potassium (~1%). Additional main elements were iron (~14.5%), silicon (~13%), and aluminium (~6%). The main trace elements in the SSA were zinc (~3750 mg/kg) and copper (~899 mg/kg). Pollutants, according to fertilizer regulations of different countries, present in Polish SSA were chromium (~703 mg/kg), nickel (~260 mg/kg), lead (~94 mg/kg), and cadmium (~9 mg/kg). The radionuclides, uranium, and thorium often present in higher amounts in commercial phosphate rock-based fertilizers, were only detected in SSA at low levels of 4-9 mg/kg and 2-3 mg/kg, respectively. Theoretical phosphorus recovery potential from the SSA (from plants in Cracow, Lodz, Gdansk, Gdynia, Szczecin, and Kielce) was estimated at 1613.8 Mg, of which 33.9% is bioavailable. Currently, in Poland, the recommended approach is the production of fertilizers as a result of the extraction of phosphorus from the SSA with its use in the production of secondary mineral fertilizers. Further research in this area is required considering Polish conditions and legislation.


Assuntos
Fósforo/análise , Esgotos , Fertilizantes , Incineração , Polônia
7.
Waste Manag ; 116: 147-156, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32799096

RESUMO

This paper reports a complete characterization of the lowest fractions of bottom ash derived from co-combustion of municipal solid waste with sewage sludge (COBA), with the aim to suggest suitable reuse strategies of this by-product. X-Ray Microanalysis is coupled with mineralogical characterization, based on X-Ray Diffraction and Rietveld refinement, to extract information about COBA crystalline and amorphous phases. The composition of different particle size fractions shows that amount of amorphous increases with the increase of fractions sizes. In particular, the finest COBA size fraction (<300 µm) shows more leachable heavy metals (i.e. Pb, and Zn) compared to the investigated fraction with the highest sizes (1400 µm). On the basis of their composition, lowest particle size fractions show a better hydraulic behavior compared to bottom ash obtained from incineration of only municipal solid waste, suggesting possible attractive COBA applications, as for example, Portland cement substitution. In addition, COBA with size fractions in the range of 1000-1400 µm are proposed to be used to produce glass and ceramic. Finally, due to its high amount of reactive amorphous phase (about 73% for fraction size of 1400 µm) COBA is used, in combination with other by-products (coal fly ash and flue gas desulphurization residues), to stabilize municipal solid waste incinerator fly ash produced at the same incinerator plant, following the azure chemistry principle of use a waste to stabilize another waste.


Assuntos
Cinza de Carvão , Metais Pesados , Incineração , Esgotos , Resíduos Sólidos/análise
8.
Waste Manag ; 114: 1-16, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32622291

RESUMO

Development of thermal processes for selective recovery of Zn and other valuable elements from municipal solid waste incineration (MSWI) fly ash requires comprehensive knowledge of the impact of gas atmosphere on the volatile behaviour of the element constituents of the ash at different reaction temperatures. This study assesses the partitioning of 18 elements (Al, As, Bi, C, Ca, Cd, Cl, Cu, K, Mg, Na, P, Pb, S, Sb, Sn, Ti, and Zn) between condensed and gaseous phases during thermal treatment of MSWI fly ash in both oxidising gas and reducing gas atmospheres, at different temperatures spanning the range 200-1050 °C. The operating atmosphere had major impacts on the partitioning of the following elements: As, Bi, C, Cd, Cu, Na, Pb, S, Sb, Sn, and Zn. The partitioning of these elements cannot be accurately predicted over the full range of investigated operating conditions with global thermodynamic equilibrium calculations alone, i.e. without also considering chemical kinetics and mass transfer. In oxidising conditions, the following elements were predominately retained in condensed phases, even at high temperatures: As, Bi, Sb, Sn, and Zn. All these elements, except As, were largely released to the gas phase (>70%) at high temperatures in reducing conditions. The impact of gas atmosphere on the volatility of Cd and Pb was greatest at low reaction temperatures (below ~750 °C). Results for volatile matrix elements, specifically C, Cl, K, Na, and S, are interpreted in terms of the mechanisms governing the release of these elements to the gas phase.


Assuntos
Metais Pesados/análise , Oligoelementos/análise , Carbono , Cinza de Carvão , Incineração , Material Particulado , Resíduos Sólidos/análise , Volatilização
9.
Waste Manag ; 114: 107-114, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32663772

RESUMO

Fly ash is a hazardous material that is produced from municipal solid waste incineration. It contains heavy metals and should be properly treated to meet landfill entry requirements. In this study, under the precondition that the leachable concentration of lead (Pb) exceeded the limit value for landfill disposal, the effects of cement solidification, chemical stabilization, and their combination on the leachable Pb concentration and the chemical state of Pb were systematically investigated. In addition, the reaction conditions were optimized by response surface methodology (RSM) in terms of leachable Pb concentration, volume change ratio, and treatment cost. The results indicated that the leachable Pb concentration decreased at lower cement or sodium dihydrogen phosphate (NaH2PO4) dosages in cement solidification or NaH2PO4 stabilization, and the liquid-to-solid ratio had a significant influence on cement solidification. The leachable Pb concentration met the limit value for landfill disposal in the individual processes with 20% cement or 5% NaH2PO4, and in the combined process with 10% cement + 2% NaH2PO4. The combined process achieved the best treatment efficiency by enabling Pb to transform to a stable residual state. According to the RSM, a combined cement content of 11.64%, NaH2PO4 content of 2.79%, and liquid-to-solid ratio of 0.48 were the optimal parameters, resulting in substantial decreases in the volume change ratio and treatment costs, while satisfying the preconditions for landfill disposal. In conclusion, the combined process can reduce the pollution risk to the environment, and is an efficient and cost-effective pre-treatment method for incinerator fly ash.


Assuntos
Metais Pesados/análise , Eliminação de Resíduos , Carbono , Cinza de Carvão , Incineração , Chumbo , Material Particulado , Fosfatos , Resíduos Sólidos/análise
10.
Waste Manag ; 114: 331-340, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32688065

RESUMO

Life Cycle Assessment (LCA) is a widespread tool used to guide decision-makers towards optimal strategic choices for sustainable growth. A key aspect of LCA studies of waste management systems where recycling activities are present is to account for resource recovery and the related substitution effects. Although multiple scientific papers assume a 1:1 substitution ratio between similar materials/products, this is often incorrect as the actual ratio is likely to vary. The focus of this paper is on the calculation of the substitutability coefficient for secondary materials based on technical characteristics. A state of the art literature review showed that many different calculation procedures were applied, which led to a wide variety of substitutability coefficients (sometimes provided under different terminology). In this perspective, the objective of this paper is to provide guidelines on the procedure to be followed to calculate the substitutability coefficient for secondary materials, based on technical characteristics. These guidelines are then applied to two waste management case studies, one dealing with bottom ashes from incineration and the other with plastic waste. In total, sixteen technical substitutability coefficients are given for ten secondary materials, based on state of the art and presented case studies. The paper thus represents a step forward in quantifying the substitutability of secondary materials in waste management LCA studies. The guidelines presented may allow other case studies to enrich the list of coefficients, useful for all LCA practitioners in a harmonized way allowing a more correct evaluation of the environmental impacts associated with recycling activities.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Meio Ambiente , Incineração , Reciclagem
11.
Bull Environ Contam Toxicol ; 105(1): 173-179, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32632464

RESUMO

In order to assess environmental exposure-associated human health risk of dioxin compounds for the population in the vicinity of a municipal solid waste incinerator (MSWI) in Shanghai, the atmospheric samples (n = 24) and soils samples (n = 96) were collected and analyzed to obtain the concentration level, pollution characteristics and seasonal changes of dioxin compounds in environmental medias. The toxicity equivalent concentration range of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was 30.9-409 fg WHO-TEQ·m-3 in atmosphere and 0.362-8.55 ng WHO-TEQ·kg-1 in soil. The non-carcinogenic health risk and carcinogenic health risk from PCDD/Fs environmental exposure of people living in the vicinity of the MSWI in Shanghai were all within the allowable range of the US Environmental Protection Agency, which implied that the MSWI in Shanghai did not produce additional risk for the population living in its vicinity.


Assuntos
Poluentes Atmosféricos/análise , Dioxinas/toxicidade , Exposição Ambiental , Incineração , Poluentes Atmosféricos/toxicidade , Atmosfera , China , Dibenzofuranos , Dibenzofuranos Policlorados/análise , Dioxinas/análise , Monitoramento Ambiental , Humanos , Dibenzodioxinas Policloradas/análise , Solo , Resíduos Sólidos/análise
12.
Environ Pollut ; 266(Pt 2): 115136, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650203

RESUMO

In compliance to European Union directives to reuse urban wastes as secondary fuels, the aim of present work was to investigate and control the environmental impact from disposal of ashes generated by combustion of a bio-solid, an olive by-product and their blend. Two waste materials were admixed with the ash and their performance as potential stabilizers was assessed. Metals and ions leached through a soil were measured. The results showed that dissolution of some alkaline substances raised the pH of water effluents, decreasing the extractability of heavy metals from the ashes. In some cases Cr and As leached reached hazardous levels. Upon addition of waste materials to ash, the concentration of Cr in liquid extracts was reduced by 35-97%, while that of Cu and As by 100%. All heavy metal values measured in the leachates were decreased to values below legislation limits. The mineralogy, the chemistry and the pH of solids involved were key factors for the retention of elements.


Assuntos
Metais Pesados/análise , Olea , Eliminação de Resíduos , Cinza de Carvão , Incineração , Solo
13.
Waste Manag Res ; 38(9): 942-965, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32705957

RESUMO

Thermogravimetric analysis (TGA) is the most widespread thermal analytical technique applied to waste materials. By way of critical review, we establish a theoretical framework for the use of TGA under non-isothermal conditions for compositional analysis of waste-derived fuels from municipal solid waste (MSW) (solid recovered fuel (SRF), or refuse-derived fuel (RDF)). Thermal behaviour of SRF/RDF is described as a complex mixture of several components at multiple levels (including an assembly of prevalent waste items, materials, and chemical compounds); and, operating conditions applied to TGA experiments of SRF/RDF are summarised. SRF/RDF mainly contains cellulose, hemicellulose, lignin, polyethylene, polypropylene, and polyethylene terephthalate. Polyvinyl chloride is also used in simulated samples, for its high chlorine content. We discuss the main limitations for TGA-based compositional analysis of SRF/RDF, due to inherently heterogeneous composition of MSW at multiple levels, overlapping degradation areas, and potential interaction effects among waste components and cross-contamination. Optimal generic TGA settings are highlighted (inert atmosphere and low heating rate (⩽10°C), sufficient temperature range for material degradation (⩾750°C), and representative amount of test portion). There is high potential to develop TGA-based composition identification and wider quality assurance and control methods using advanced thermo-analytical techniques (e.g. TGA with evolved gas analysis), coupled with statistical data analytics.


Assuntos
Resíduos de Alimentos , Eliminação de Resíduos , Incineração , Resíduos Sólidos/análise , Termogravimetria
14.
Waste Manag ; 113: 447-455, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32604007

RESUMO

Harmless treatment and reuse of municipal solid waste incinerator fly ash are challenging. Two reuse technologies of converting incinerator fly ash to ceramsites via rotary kiln sintering and non-sintering have been demonstrated in China. Field monitoring results reveal that the destruction efficiency of PCDD/Fs are both higher than 99% in two processes. The leaching rate of heavy metals in both ceramsite products, their pollutant emissions in production process meet the standards. Environmental impacts of two ceramsite products were compared using life cycle assessment approach. Rotary kiln sintering ceramsite has lower environmental impacts in most categories and delivers a smaller integrated impacts index than non-sintering ceramsite. For rotary kiln sintering ceramsite, transportation, electricity and curing agent in dust disposal are the most significant contributors to most of environmental impacts categories results, accounting for 33.7%, 29.0% and 24.6% to the integrated impacts index, respectively. For non-sintering ceramsite, curing agent and electricity contribute 69.6% and 15.8% to the integrated impacts index, respectively. Based on these life cycle assessment results, recommendations for current plant operation and new plants planning are proposed.


Assuntos
Metais Pesados/análise , Dibenzodioxinas Policloradas , Eliminação de Resíduos , Carbono , China , Cinza de Carvão , Dibenzofuranos , Incineração , Material Particulado , Resíduos Sólidos
15.
Waste Manag ; 113: 488-496, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32619783

RESUMO

With the purpose of fully understanding the potential toxicity of heavy metals of various particle sizes in fly ash (FA) and finding an optimal chemical reagent stabilization scheme for fly ash with single or mixture reagents, basic physicochemical characteristics of FA was investigated using multiple chemical stabilization reagent schemes to stabilize heavy metals. The following compounds were used to develop single and mixed chemical stabilization schemes for heavy metals in waste incineration FA: sodium sulfide (Na2S), sodium dihydrogen phosphate (NaH2PO4), ammonium dibutyl dithiophosphate (DDTP), and 2,4,6-tri-mercapto-S-triazine trisodium salt (TMT-15). The results showed that the various particle sizes of FA were mainly distributed in the range of 48-1700 µm. FA was packed with heavy metals, and the smaller the particle size, the more toxic it was. The speciation distribution of Cu, Zn, Pb, Cd, and Cr in different particle sizes was identical to that of the mixed samples. In the experiments of single reagent stabilization scheme, 8% Na2S, 8% NaH2PO4, 4.2% DDTP or 4.2% TMT-15 could decrease the leaching concentration to meet the limits set by Chinese law, but 8% Na2S adding scheme had the lowest cost among them. However, in the mixture reagent scheme, 1.2% Na2S, 1.2% NaH2PO4 and 0.8% DDTP was more effective and even cheaper than other mixture or single schemes.


Assuntos
Metais Pesados/análise , Eliminação de Resíduos , Carbono , Cinza de Carvão , Incineração , Material Particulado , Resíduos Sólidos
16.
Environ Sci Pollut Res Int ; 27(25): 32139-32151, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32577969

RESUMO

High temperature melting treatment and cement solidification are technologies currently used to reduce the leaching of heavy metals in municipal solid waste incinerator (MSWI) fly ash. In this paper, to ascertain the feasibility of melting MSWI fly ash with blast furnace (BF) slag, ultra-risk MSWI(U-MSWI) fly ash having high heavy metal (Zn, Pb, Cu, and Cr) contents were blended with BF slag, then melted and quenched into water to prepare reconstructed slag. The melting and solidification behaviors, phase composition and microstructure, and heavy metal leachability of reconstructed slag were studied. In addition, to study the further solidification and utilization of reconstructed slag in cement, the compressive strength and leaching concentration of cement composites with reconstructed slag were also investigated. The results indicate that the presence of heavy metals in the U-MSWI fly ash had a little influence on the microstructure and phase composition of reconstructed slag. The leaching concentration of heavy metals in the reconstructed slag increased with the increasing of U-MSWI fly ash content, and when the content of U-MSWI fly ash was less than 50 wt%, the reconstructed slag could meet the environmental requirements. The reconstructed slag further solidified by cement could be applied to landfill and construction materials. The technology of melting reconstruction treatment with cement solidification was a technical-economical choice for the industrial treatment of U-MSWI fly ash.


Assuntos
Metais Pesados/análise , Eliminação de Resíduos , Carbono , Cinza de Carvão , Materiais de Construção , Incineração , Material Particulado , Resíduos Sólidos
17.
PLoS One ; 15(6): e0234476, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584848

RESUMO

Soils contaminated with per- and polyfluoroalkyl substances (PFASs) are an important source for impacting drinking water delivery systems and surface water bodies world-wide, posing an urgent risk to human health and environmental quality. However, few treatment techniques have been tested for PFAS-contaminated soil hotspots. This study investigated the possibility of thermal desorption as a possible technique to remediate soils contaminated with multiple PFASs. Two fortified soils (∑9PFAS ≈ 4 mg kg-1) and one field-contaminated soil (∑9PFAS ≈ 0.025 mg kg-1) were subjected to a 75-min thermal treatment at temperatures ranging from 150 to 550°C. Soil concentrations of PFASs showed a significant decrease at 350°C, with the ∑9PFAS concentration decreasing by, on average, 43% and 79% in the fortified and field contaminated soils, respectively. At 450°C, >99% of PFASs were removed from the fortified soils, while at 550°C the fraction removed ranged between 71 and 99% for the field contaminated soil. In the field contaminated soil, PFAS classes with functional groups of sulfonates (PFSAs) and sulfonamides (FOSAs) showed higher removal than the perfluoroalkyl carboxylates (PFCAs). Thus thermal desorption has the potential to remove a wide variety of PFASs from soil, although more studies are needed to investigate the cost-effectiveness, creation of transformation products, and air-phase vacuum filtration techniques.


Assuntos
Alcanossulfonatos , Recuperação e Remediação Ambiental/métodos , Fluorcarbonetos , Incineração/métodos , Poluentes do Solo
18.
Waste Manag ; 112: 11-19, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32480299

RESUMO

Valuable non-ferrous (NFe) metals are contained in municipal solid waste incineration (MSWI) bottom ash (BA). The applicability of an air table for separating NFe metal-abundant particles in MSWI BA (<8 mm) was studied. A stepwise separation procedure was developed based on the performance tests of the air table conducted by changing three variables (air injection, vibration, and end slope). As a result of the stepwise separation, six bulk density ranges (<0.7 to >1.1 g/cm3 at intervals of 0.1 g/cm3) were prepared from non-magnetic fractions with four size ranges (4-8, 2-4, 1-2, and 0.5-1 mm). The effectiveness of air table sorting was evaluated based on dry particle density and proportion of metals. NFe metals were obtained by sieving (>0.5 mm) after a ball mill process, confirming that NFe metals accounted for 3.2% of the < 8 mm MSWI BA. The highest particle density of each size fraction and the proportion of NFe metals in the fractions were 3.19 g/cm3 and 59.9% (4-8 mm), 2.97 g/cm3 and 28.8% (2-4 mm), 2.78 g/cm3 and 10.4% (1-2 mm), and 2.87 g/cm3 and 4.4% (0.5-1 mm). In the 0.5-2 mm particles, the highest density fraction contained 68.7% of the NFe metals, which were expected to be recovered by applying an air table separator to MSWI BA 0.5-2 mm.


Assuntos
Metais Pesados , Resíduos Sólidos , Cinza de Carvão , Incineração , Fenômenos Magnéticos , Metais
19.
Environ Monit Assess ; 192(7): 423, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32524340

RESUMO

A total of 209 different types of polychlorinated biphenyls (PCBs) with various properties have been produced from 1930 to 1970s in which they have been banned due to their toxic effects. Total produced PCBs in the world are around 15 to 20 million tons, and up to now, 5.4 million tons of PCB-containing or PCB-contaminated equipment/materials has been eliminated. The remaining 10-15 million tons still needs to be removed or managed. Moreover, PCBs are pollutants still being unintentionally formed. These pollutants can be treated or disposed of various methods. However, there is a lack of knowledge about the selection of the treatment and disposal methods and their environmental, technological, cost, and social/ergonomic evaluation perspectives and the risk assessment during method selection. In this study, a projection was presented for the management of PCBs with an integrated multi-criteria decision-making (MCDM)-risk analysis focusing on these questions. Treatment (physical, chemical, biological) and disposal (incineration, landfill, supercritical water oxidation/gasification (SCWO/G), and pyrolysis/gasification) methods for the management of PCB-containing waste have been prioritized by fuzzy-analytical hierarchy process (F-AHP) in terms of environmental, technology, cost, and social/ergonomic criteria. Risk analysis was also made in terms of these criteria for considered alternatives, and compliance with risk and MCDM was evaluated. As a result of the study, priority methods among alternatives were determined as chemical treatment and SCWO/G. It has been determined that the weight values of the main criteria of environmental, technology, cost, and social/ergonomics were close to each other, but the emission criterion of the sub-criteria was determined to be of higher priority. In the risk analysis, chemical treatment and SCWO/G methods have been found to carry a more acceptable risk. Thus, it has been evaluated that these methods provide more superiority than other methods.


Assuntos
Monitoramento Ambiental , Incineração , Bifenilos Policlorados , Medição de Risco , Instalações de Eliminação de Resíduos
20.
Environ Sci Pollut Res Int ; 27(26): 32637-32658, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32514910

RESUMO

Municipal solid waste (MSW) incineration contributes significantly to carbon emissions, and has become a serious problem in China, which has seen an exponential rise in waste over the last twenty years due to rapid urbanization and the associated consumer economy growth. To tackle this issue, this paper develops a leader-follower optimized approach for economic and environmental equilibrium in incineration power plants that includes a carbon allowance allocation scheme (IPP-CAAS) under combustion and pollutant limitations. In the leader-follower (bi-level) game, the regional authority on the upper level determines the carbon allocations and environmental targets and the IPPs on the lower level develop schemes to maximize revenue under the upper-level restrictions. By employing uncertain parameters for the carbon and power conversion fluctuations, the approach is able to more accurately depict the industry characteristics of waste incineration process in this carbon-economy balance problem. The robustness and practicality of the proposed methodology was then validated through a case study. Scenario analysis under different political parameters indicates that the proposed methodology can assist the authorities to achieve carbon-economy trade-off and under serious carbon-control situations, encourage the IPPs to reduce their blended coal ratios, and invest in low-carbon incineration technology. Managerial insights on further industrial developments are also given for the authority and relevant practitioners.


Assuntos
Incineração , Resíduos Sólidos/análise , Carbono , China , Carvão Mineral
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