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1.
Ecotoxicol Environ Saf ; 208: 111596, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396117

RESUMO

The surge in solid waste (SW) has become major issues in the fields of public health and ecological environment fuelled by the rapid development of social economy. The fate of nitrogen contained in SW (SWN) varies with different treatment methods, which will affect the environment to varying degrees. It is of great practical and guiding significance to comprehensively evaluate the sources, fate and its cascading effects of SWN. Here, a systematic SWN flow evaluation of the generation, treatment and emissions in China from 2008 to 2017 was established. During this period, the SWN flow and the N pollution emissions from SW treatment increased by 19.7% and 27.6% respectively, with the domestic garbage being the largest contributor. This shows that it is particularly important to reinforce the classified of domestic garbage and resource recycling in China. Landfill was the main treatment, accounting for 51.8% of the total SWN. Landfill and incineration were the main sources of pollution N emissions, while compost treatment has the lowest contribution rate. It highlights the urgency of changing the waste treatment methods in China. About 92.3% of the N pollution emissions was lost to the atmosphere and 7.7% to the groundwater. NH3 and NOx were the main pollutants to the atmosphere. Special attention is paid to the reduction and control of NH3 in landfill, dumping and compost processes, while NOx in incineration. This study provides scientific basis for management and disposal of SW, so as to reduce its impact on the ecological environment and develop more sustainable policies for China and other developing countries.


Assuntos
Nitrogênio/análise , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , China , Meio Ambiente , Poluição Ambiental , Incineração/métodos , Reciclagem , Instalações de Eliminação de Resíduos
2.
Chemosphere ; 261: 127789, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32739693

RESUMO

Magnesium potassium phosphate cement (MKPC) is prepared from MgO and KH2PO4 through an acid-base reaction and has been widely used in the rapid repairs of building structures and the solidification/stabilization (S/S) of heavy metals (HMs). The use of sludge incineration residue (SIR) rich in phosphorus resources to prepare SIR-based MKPC can achieve the reclamation of SIR and efficient HM S/S. Herein, based on the exploration of the optimal MKPC magnesia/phosphate ratio (M/P), the effects of SIR and HMs on the performance of the matrix and its interaction mechanism were comprehensively investigated. The results indicated that the compressive strength of the SIR-based MKPC increased first and then decreased with the gradual increase of SIR incorporation; the optimal was reached at 40.31 MPa when the SIR incorporation was 5 wt%. The peak signal and crystal lattice of Pb2(PO4)3 indicated that there is a mixed effect between HMs (in SIR) and KH2PO4. The Visual MINTEQ analysis results also indicated that HMs are precipitated as HM phosphates. The formation of HM phosphates not only increases the M/P (with 30 wt% SIR, M/P increased by 0.019), affecting the microstructure and changing the compressive strength of the matrix, but also promotes the transformation of HMs from the bioavailable to the more stable residual forms. The residual forms of the six HMs were all above 84% after S/S. Therefore, the SIR-based MKPC preparation significantly immobilized the HMs; particularly, the leaching toxicities of Cu (96.6%) and Zn (96.3%) were alleviated.


Assuntos
Materiais de Construção , Incineração/métodos , Metais Pesados/química , Fosfatos/química , Compostos de Potássio/química , Força Compressiva , Magnésio , Compostos de Magnésio , Minerais/química , Potássio , Esgotos/química
3.
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
4.
Chemosphere ; 257: 127168, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32480089

RESUMO

Waste incineration is a preferred method in China to dispose the municipal solid waste, but controlling the production of highly toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans effectively during incineration is both challenging and imperative. In this study, the suppression of PCDD/Fs by various phosphorus-containing compounds was explored, and the mechanisms responsible for the inhibition were studied in detail. The experiments took place in a lab-scale vertical tubular reactor at 350 °C under a simulated flue gas (12 vol% O2 in N2 flow), and both the off-gases and residues were collected for PCDD/Fs analysis. The scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to characterize the reaction residues. The experimental results revealed that NH4H2PO4 and (NH4)2·HPO4 showed the highest inhibitory effect (57.2% and 57.3%, respectively) on the PCDD/Fs formation, followed by CaHPO4 with inhibition efficiency of 39.1%. In contrast, KH2PO4 and K2HPO4 barely inhibited the generation of the PCDD/Fs. The inhibitory effect of NH4H2PO4 and (NH4)2·HPO4 was similar to that of nitrogen-based inhibitors. At the same time, it was proven that the inhibitory activity of CaHPO4 might be due to the reaction of it with Cu2+ forming stable compounds.


Assuntos
Dibenzofuranos Policlorados/toxicidade , Dibenzofuranos/toxicidade , Dibenzodioxinas Policloradas/toxicidade , China , Cinza de Carvão/química , Dibenzofuranos Policlorados/química , Gases/análise , Incineração/métodos , Fósforo , Compostos de Fósforo , Dibenzodioxinas Policloradas/análise , Resíduos Sólidos
5.
Chemosphere ; 252: 126436, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32182511

RESUMO

Ash products from coal and municipal solid waste combustion constitute a waste stream with characteristics that, unless recycled, require specific disposal practices. Although traditional disposal involves ash placement in a cell dedicated solely for the ash (monofill), new regulations for the management of coal combustion residues in the US might lead to more co-disposal of these residues with unburned municipal solid waste (MSW) that has not been combusted or otherwise processed. Both monofill and co-disposal practices are currently utilized for MSW incineration ash in the US. Column tests were performed using landfill leachate as a leaching solution to simulate co-disposal conditions of ash with MSW, while DI water was used to simulate monofilling. Mobility of As, B and V from coal fly ash was enhanced in the presence of landfill leachate in both batch and column tests, and a similar trend was observed for Cd and Mo release from MSW incineration ash. For several elements, release was greater with the column procedure relative to the batch procedure. The results suggest that long-term implications of co-disposal should be factored into decisions regarding which disposal scenario to pursue.


Assuntos
Incineração/métodos , Oligoelementos/análise , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , Água , Poluentes Químicos da Água/análise
6.
J Environ Public Health ; 2020: 2934296, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32190061

RESUMO

Hospital waste management in Ghana faces the risk of cross-contamination from the lack of thorough sorting of the waste at the points of generation, codisposal of hazardous and nonhazardous waste types, and use of open-fire pits and substandard incinerators for burning infectious waste. This has increased the potential for the spread of infections and chemical pollutants. A cross-sectional study was conducted in five hospitals in Ghana to assess behavioral patterns on waste sorting and the effectiveness of hospital waste management in Ghana. A total of 250 questionnaires were distributed purposively to some staff of the five hospitals to assess workers' perceptions on medical waste sorting and handling. Additionally, focused group discussions and transect walks were adopted to examine the current collection, storage, treatment, and disposal methods used in the health facilities. Chi-square analyses showed significant differences in waste-sorting behavior based only on occupation (p < 0.0001, n=180) and not on gender, education, or experience in the health sector. Even though contaminated sharps were separated into brown safety boxes, color coding for other infectious waste containers was inconsistent across the health facilities. The study revealed that incineration is still the modal method of treatment in Ghanaian hospitals and therefore new approaches such as an engineering approach were required to minimize its environmental effects. It is recommended that periodic in-service training workshops be held for healthcare staff on the right source-segregation of medical waste, in order to facilitate the effective and safe handling, transport, treatment, and disposal of waste from health facilities.


Assuntos
Instalações de Saúde/estatística & dados numéricos , Eliminação de Resíduos de Serviços de Saúde/métodos , Estudos Transversais , Gana , Pesquisas sobre Serviços de Saúde , Conhecimentos, Atitudes e Prática em Saúde , Pessoal de Saúde/educação , Pessoal de Saúde/estatística & dados numéricos , Humanos , Incineração/métodos , Incineração/normas , Serviço Hospitalar de Engenharia e Manutenção/métodos , Serviço Hospitalar de Engenharia e Manutenção/normas , Eliminação de Resíduos de Serviços de Saúde/normas
7.
Chemosphere ; 252: 126541, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32217411

RESUMO

Emission factor and removal efficacy of PCNs are evaluated via the flue gas sampling of two MWIs equipped with different air pollution control devices (APCDs) in Taiwan. MWI-A is equipped with ESP, wet scrubber (WS) and selective catalytic reduction (SCR), while cyclone (CY), semi-dry absorber (SDA), activated carbon injection (ACI) and baghouse (BH) are employed in MWI-B. The average concentrations of PCNs measured at stacks of MWI-A and MWI-B are 2.1 ng Nm-3 (0.218 pg TEQ Nm-3) and 23.2 ng Nm-3 (0.425 pg TEQ Nm-3), respectively. The emission factors of PCNs calculated from feeding rates of waste and stack sampling results range from 6.7 to 6.95 µg t-1 (0.790-1.45 ng TEQ t-1). PCNs are formed in ESP via chlorination, while SCR and SDA + ACI + BH are effective in removing PCNs with the overall efficacies of 97.6% and 94.3%, respectively. PCN removal efficiencies achieved with SCR and SDA + ACI + BH increase as chlorination level increases. Specifically, around 72% and 82% of Mono-CN are removed by SCR and SDA + ACI + BH, respectively. The removal efficacies of other homologues achieved with SCR are consistently high (96-100%). Dominances of Mono-to Tri-CNs in scrubbing liquid collected from WS and higher removal efficacies of these homologues achieved with WS + ESP compared with ESP alone indicate that WS can capture low chlorinated PCNs to some extent. The results suggest that CY + SDA + ACI + BH should be equipped in MWI for effective removal of PCNs, while ESP, WS and SCR should be utilized with precaution to eliminate PCNs formation and enhance the PCNs removal efficiency.


Assuntos
Monitoramento Ambiental , Incineração/métodos , Naftalenos/química , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Catálise , Taiwan
8.
Molecules ; 25(3)2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-32046287

RESUMO

Methomyl is a broad-spectrum oxime carbamate commonly used to control arthropods, nematodes, flies, and crop pests. However, extensive use of this pesticide in agricultural practices has led to environmental toxicity and human health issues. Oxidation, incineration, adsorption, and microbial degradation methods have been developed to remove insecticidal residues from soil/water environments. Compared with physicochemical methods, biodegradation is considered to be a cost-effective and ecofriendly approach to the removal of pesticide residues. Therefore, micro-organisms have become a key component of the degradation and detoxification of methomyl through catabolic pathways and genetic determinants. Several species of methomyl-degrading bacteria have been isolated and characterized, including Paracoccus, Pseudomonas, Aminobacter, Flavobacterium, Alcaligenes, Bacillus, Serratia, Novosphingobium, and Trametes. The degradation pathways of methomyl and the fate of several metabolites have been investigated. Further in-depth studies based on molecular biology and genetics are needed to elaborate their role in the evolution of novel catabolic pathways and the microbial degradation of methomyl. In this review, we highlight the mechanism of microbial degradation of methomyl along with metabolic pathways and genes/enzymes of different genera.


Assuntos
Inibidores da Colinesterase/metabolismo , Inseticidas/metabolismo , Metomil/metabolismo , Poluentes do Solo/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Alcaligenes/metabolismo , Bacillus/metabolismo , Biodegradação Ambiental , Flavobacterium/metabolismo , Humanos , Incineração/métodos , Redes e Vias Metabólicas/fisiologia , Oxirredução , Paracoccus/metabolismo , Pseudomonas/metabolismo , Serratia/metabolismo , Trametes/metabolismo
9.
Chemosphere ; 249: 126115, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32045756

RESUMO

The BCR sequential extraction scheme (SES), initially developed for soils and sediments, is frequently adopted to evaluate the environmental risks of municipal solid waste incineration (MSWI) fly ash. Within the procedure, metals are liberated from the matrix hosting them relying on the selectivity of the chosen chemical reagents or operation conditions. However, the effect of the high content of alkaline substances in MSWI fly ash on the selectivity of acetic acid to acid-soluble fraction metals was ignored. In this study, the feasibility of the BCR SES for evaluating MSWI fly ash was assessed by adjusting the acetic acid washing times in the acid-soluble extraction step. The metal fractionation, as well as mineralogy, morphology, and surface chemistry of the residues after three successive acid washing processes, were analyzed. The results reveal that only easily soluble salts, but not hydroxides, are entirely extracted after the first acid washing (pH∼12.0). Importantly, carbonates (generally reported as an indicator of the complete release of acid-soluble metals) are mostly decomposed only after the third acid washing (pH∼3.8). The incomplete dissolution of calcium carbonates in a single-step acid washing may convey misleading results of metal fractionation and underestimates the environmental risk of potentially toxic elements. Therefore, complete removal of carbonates should be employed as the endpoint of the acid-soluble fraction extraction step in the evaluation of MSWI fly ash. This work can help in selecting proper strategies for fly ash management and developing proper sequential extraction schemes for similar high-alkalinity hazardous waste risk assessment.


Assuntos
Incineração/métodos , Metais Pesados/análise , Carbono/química , Carbonatos/química , Fracionamento Químico , Cinza de Carvão/química , Material Particulado/química , Eliminação de Resíduos , Sais , Resíduos Sólidos/análise , Oligoelementos/análise
10.
Chemosphere ; 244: 125479, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31816551

RESUMO

Membrane concentrated leachate is an important secondary pollutant in incineration plants and needs to be treated properly in order to achieve the "zero discharge" standard for pollutants from incineration plants. In this study, coagulation followed by the electro-oxidation (EO), and electro-coagulation (EC) methods were studied. Each of these processes was used to treat the spacer tube reverse osmosis membrane concentrated leachate from an incineration plant. A single factor experiment was used to determine the optimal conditions for each individual process. In addition, a two-stage electrochemical treatment was investigated after combining the optimized EO and EC processes. The results showed that the two-stage electrochemical treatment process can achieve much higher removal efficiencies than when only EO or EC are applied. The optimal conditions for the two-stage electrochemical treatment process were 180 min of the optimized EO process as the 1st stage treatment process, followed by 60 min of the optimized EC process as the 2nd stage treatment process. After the optimized coagulation-EO-EC process, the total organic carbon (TOC), UV254, ammonia nitrogen (NH3-N), total nitrogen (TN), color (CN), turbidity (TUB), and solution conductivity (SC) removal efficiencies were 96.19%, 98.98%, 96.54%, 88.21%, 99.72%, 98.24%, and 54.67%, respectively. This study can provide a theoretical basis for the treatment of concentrated leachate from MSW incineration plants.


Assuntos
Incineração/métodos , Amônia , Filtração/métodos , Nitrogênio , Osmose , Oxirredução , Centrais Elétricas , Poluentes Químicos da Água/análise
11.
Chemosphere ; 243: 125351, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31756654

RESUMO

Hazardous waste disposal is a serious environmental concern in China. Therefore, in this study, industrial trials were conducted in a low-temperature thermal degradation facility, a tunnel kiln, and a shaft kiln to effectively treat dioxins in municipal solid waste incineration (MSWI) fly ash. The results indicated that the low-temperature thermal degradation facility efficiently decomposed polychlorinated dibenzo-p-dioxins and dibenzofurans in the MSWI fly ash. Additionally, the concentrations of dioxins in the treated fly ash and exhaust gas were lower than the suggested standard limits and the degradation ratio of dioxins was ∼99%. Therefore, treated fly ash characterized by acceptable dioxin risks could be utilized for the production of non-fired building materials. The results from the tunnel kiln indicated complete decomposition of the dioxins in the firing and insulating sections. However, the addition of fly ash in the tunnel kiln increased the concentration of dioxins in the flue gas. This can be primarily attributed to the heterogeneous catalytic synthesis reaction in the low-temperature section of the tunnel kiln. The results from the shaft kiln indicated degradation of at least 22% of the dioxins in the ash. The dioxin concentration in the flue gas was lower than the national standard while that in the clinker was within a reasonable limit. Furthermore, the environmental risks were significantly reduced at fly ash addition ratios lower than 3%.


Assuntos
Dibenzofuranos Policlorados/química , Resíduos Perigosos/análise , Incineração/métodos , Dibenzodioxinas Policloradas/química , China , Cinza de Carvão , Materiais de Construção , Dibenzofuranos , Dioxinas , Indústrias , Dibenzodioxinas Policloradas/análise , Eliminação de Resíduos , Resíduos Sólidos
12.
Chemosphere ; 239: 124614, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31505444

RESUMO

Studies are carried out in two wet scrubbing systems (WSSs) subordinated to two similar full-scale (30 t h-1) municipal solid waste (MSW) incinerators to explore the influence factors and mass balance of memory effect on polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) emissions. The results show that the memory effect on two WSSs notably increases the TEQ concentrations by 13.6 and 3 times, respectively, through increase in the total mass concentration and the proportions of low-chlorinated PCDD/Fs, directly resulting in the PCDD/F emissions of 1# MSW incinerator over the national standard. PCDD/F adsorption/desorption in WSSs is the reasonable acting mechanisms of memory effect. In addition, memory effect mainly influences gaseous PCDD/F emissions by elevating the percentage of PCDFs, while slightly affects PCDD/Fs in residuals. A mass balance of PCDD/Fs is established to further analyze the influence factors of memory effect on WSSs, indicating filling as the largest potential source discharging PCDD/Fs into outlet flue gas. The results pave the way for further industrial optimization of WSSs design, such as the filling materials with less adsorption capacity on PCDD/Fs and more reasonable operation.


Assuntos
Poluentes Atmosféricos/análise , Benzofuranos/análise , Dibenzofuranos Policlorados/análise , Incineração/métodos , Dibenzodioxinas Policloradas/análise , Resíduos Sólidos/análise , China , Monitoramento Ambiental/métodos , Gases
13.
Chemosphere ; 240: 124892, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31546192

RESUMO

This experimental research studies co-combustion of wet coal processing waste (filter cakes) with typical municipal solid waste (wood, rubber, plastic, cardboard) and used turbine oil, as combustible components of composite liquid fuel. Ignition mechanisms and characteristics of single droplets of three fuel composition groups have been investigated in a motionless heated air with using a high-speed video recording system. Analyzing video frames, a physical model of the process under study was developed. The values of the guaranteed ignition delay times have been determined for three fuel groups with different compositions at the ambient temperature 600-1,000 °C. The minimum values of ignition delay times are about 3 s, the maximum ones are about 25 s. In addition to the established difference in the ignition delay times, the various fuel compositions also differ in combustion temperatures. Maximum values reaching 1,300 °C for compositions with 10% of used oil. It has also been determined that fuels with municipal solid waste are notable for lower nitrogen and sulfur oxide concentrations in flue gases as compared to filter cakes in initial state. Adding used oil to such fuel compositions increases the anthropogenic emissions but these worsening environmental characteristics do not exceed the regulated allowable limits of pollutants for solid fossil fuel combustion by thermal power plants. The obtained results are the backbone for the development of an environmentally friendly, cost- and energy-efficient co-combustion technology for municipal solid waste recovery by burning it as part of composite fuels, e.g., in boiler furnaces instead of coal.


Assuntos
Poluentes Atmosféricos/análise , Carvão Mineral/análise , Óleos Combustíveis/análise , Incineração/métodos , Poluição por Petróleo/análise , Centrais Elétricas , Resíduos Sólidos/análise
14.
Aust N Z J Public Health ; 44(1): 40-48, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31535434

RESUMO

INTRODUCTION: Waste incineration is increasingly used to reduce waste volume and produce electricity. Several incinerators have recently been proposed in Australia and community groups are concerned about health impacts. An overview of the evidence on health effects has been needed. METHOD: A systematic review of English language literature for waste incinerators and health using PRISMA methodology. RESULTS: A range of adverse health effects were identified, including significant associations with some neoplasia, congenital anomalies, infant deaths and miscarriage, but not for other diseases. Ingestion was the dominant exposure pathway for the public. Newer incinerator technologies may reduce exposure. DISCUSSION: Despite these findings, diverse chemicals, poor study methodologies and inconsistent reporting of incinerator technology specifications precludes firmer conclusions about safety. CONCLUSION: Older incinerator technology and infrequent maintenance schedules have been strongly linked with adverse health effects. More recent incinerators have fewer reported ill effects, perhaps because of inadequate time for adverse effects to emerge. A precautionary approach is required. Waste minimisation is essential. Implications for public health: Public health practitioners can offer clearer advice about adverse health effects from incinerators. We suggest improved research design and methods to make future studies more robust and comparable. We offer ideas for better policy and regulation.


Assuntos
Exposição Ambiental/efeitos adversos , Incineração/métodos , Neoplasias , Austrália , Humanos , Vigilância da População , Saúde Pública
15.
Environ Sci Pollut Res Int ; 26(35): 35687-35703, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31745800

RESUMO

Facing the common treatment problems of dioxin whose major sources come from waste incineration and steel sintering, we handled a massive literature dataset from the Web of Science database and analyzed the research hotspot and development trend in this field in the past 40 years by bibliometric method. The result indicates that the field of dioxins generated from waste incineration and steel sintering has entered a stage of rapid development since 1990. China occupies a leading position in terms of comprehensive strength with the largest publications output as well as a greater influence in recent years. The most productive institutions and journals are Zhejiang University and Chemosphere, respectively. In addition, the most commonly used keywords in statistical analysis are "fly ash," "emission control," "risk assessment," "congener profile," "formation mechanisms," "sources," "catalysis," and "inhibition," which reflects the current main research direction in this field. The similarities and differences of dioxins generated in waste incineration and steel sintering are reviewed in this paper, which will provide guidance for the future research.


Assuntos
Cinza de Carvão/análise , Dioxinas/análise , Incineração/métodos , Bibliometria , China , Dibenzodioxinas Policloradas/análise , Medição de Risco , Aço
16.
Environ Sci Pollut Res Int ; 26(33): 34613-34621, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31654307

RESUMO

Spraying concentrated leachate into an incineration furnace and burning is encouraged by the Chinese government as a harmless method for leachate treatment. In this research, the constituent transformation mechanism was studied, by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS), of residues after burning the concentrated leachate in a muffle furnace at different temperatures (750 °C, 850 °C, 900 °C, 1000 °C, and 1100 °C). XRD results showed that the main components of the residues were metal chlorides and calcium salt crystals and that the peak position of most of these crystals changed little because their crystal structure was stable at high temperatures. SEM results illustrated that the higher the burning temperature, the smaller the solid particles, and the looser the structures of the residues. EDS analysis showed that S atoms in the concentrated leachate were usually transformed into gaseous compounds during incineration, whereas most of the Cl atoms could be fastened onto solid residues if an appropriate temperature was maintained. This study concluded that 900 °C was the best burning temperature for spraying concentrated leachate into the furnace. In addition, this study suggested that material selection for the nozzle and flue gas pipelines must pay more attention to corrosion caused by gaseous sulfur compounds. Similarly, material selection for the inner wall of the incinerator furnace should pay more attention to corrosion caused by Cl atoms. This means that the municipal solid waste (MSW) incineration power plants should incorporate various and appropriate corrosion-resistant materials according to the different regions of the incinerator.


Assuntos
Incineração/métodos , Temperatura , Cloretos/análise , Corrosão , Gases/análise , Centrais Elétricas , Eliminação de Resíduos , Resíduos Sólidos/análise
17.
Chemosphere ; 226: 898-906, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31509919

RESUMO

In recent years, concerns over some per- and polyfluorinated alkyl substances (PFAS) have grown steadily. PFAS are a large group of chemical substances with widely differing properties. While one class of PFAS, fluoropolymers, have been demonstrated to meet the OECD criteria for polymers of low concern during the in use phase of their lifecycle, questions remain regarding waste handling at the end of useful life for products containing fluoropolymers. To show that polytetrafluoroethylene (PTFE) can be almost fully transformed into fluorine (F) (as hydrofluoric acid (HF)) and to study the possible generation of low molecular weight per- and polyfluorinated alkyl substances (PFAS), PTFE combustion under typical waste incineration conditions at the BRENDA (German acronym for "Brennkammer mit Dampfkessel") pilot plant at Karlsruhe Institute of Technology (KIT) was investigated. Results indicate that, within procedural quantitation limits, no statistically significant evidence was found that the PFAS studied were created during the incineration of PTFE. Therefore, municipal incineration of PTFE using best available technologies (BAT) is not a significant source of the studied PFAS and should be considered an acceptable form of waste treatment.


Assuntos
Fluorcarbonetos/análise , Gases/análise , Incineração/métodos , Politetrafluoretileno/química , Resíduos Sólidos
18.
Environ Sci Pollut Res Int ; 26(29): 29917-29929, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31410836

RESUMO

Phosphorus (P), an irreplaceable nutrient for all living organisms, is facing scarcity via phosphate resources. In this research, the effect of suitable additives and temperature on P and heavy metals speciation during sewage sludge (SS) thermochemical treatment was investigated. The results demonstrated that additives (CaO and MgO) could promote the conversion of non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP). X-ray diffraction measurements indicated that the phosphorus mineral phase in sewage sludge ash (SSA) mainly was AP, with addition of MgO and CaO. Moreover, orthogonal testing revealed that the optimal molar ratio of Mg:Ca:P for P recovery as AP was 1:3.5:1 at 750 °C. Risk index results implied that the heavy metals in the phosphorus-enriched SSA have low potential ecological risk. Thermodynamic equilibrium calculations revealed that P reacted with the other metal ions was in the following order: Ca2+ > Mg2+ > Al3+ > Fe3+ > Zn2+ > K+. Graphical Abstract.


Assuntos
Incineração/métodos , Metais Pesados/química , Fosfatos/química , Fósforo/química , Esgotos/química , Apatitas/química , Temperatura Alta , Difração de Raios X
19.
Environ Sci Pollut Res Int ; 26(26): 27239-27258, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31321717

RESUMO

This study was conducted to assess the vulnerability of areas allocated for sanitary landfill in Nakhon Ratchasima and for incineration in Phuket, Thailand, and to investigate the factors contributing to their vulnerability. Analysis was conducted to develop a vulnerability index using a composite index approach and the Intergovernmental Panel on Climate Change (IPCC) framework approach, while correlation and t tests were applied to identify the relationships and differences between the two systems. Additionally, vulnerability indices were developed using the IPCC vulnerability definition. The results suggested that the vulnerability of the areas allocated for sanitary landfill and incineration were not significantly different. The factor that had the greatest impact on the vulnerability of the sanitary landfill was nuisance, while sub-component correlation analysis revealed that cadmium in groundwater was significantly negatively correlated with vulnerability (r = - 0.958, p < 0.05). Furthermore, the factor that had the greatest effect on vulnerability from incineration was leachate. Similarly, correlation analysis suggested that the chemical oxygen demand in leachate and solid waste residues was significantly positively correlated with vulnerability (r = 0.981, 0.975 respectively, p < .05). It is hoped that these findings can be used to establish measures for preventing environmental problems, as well as to prioritize and identify issues that need to be resolved urgently, and to help policy makers select appropriate systems for different regions of Thailand.


Assuntos
Incineração/métodos , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , Tailândia , Instalações de Eliminação de Resíduos
20.
Environ Pollut ; 253: 171-180, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31306824

RESUMO

In order to exhaustively investigate the physical and chemical mechanisms of heavy metal immobilization in sludge incineration residue (SIR)-based magnesium potassium phosphate cement (MKPC), this work investigated the influence of Pb2+ and Zn2+ on the compressive strength and microstructure of SIR-based MKPC, and the efficiency of Pb and Zn immobilization. Taking the difference of Ksp (solubility product) of different heavy metal compounds as the entry point, the physical and chemical mechanisms of Pb and Zn immobilization, and the competitive mechanism between coexisting ions, were comprehensively analyzed. It was discovered that Pb2+ is in the form Pb3(PO4)2, and Zn2+ is immobilized in the form Zn2(OH)PO4 [Zn3(PO4)2 is preferentially formed, when the pH > 7, Zn3(PO4)2 is converted to Zn2(OH)PO4]. The low solubility of heavy metal phosphates is the main reason that Pb2+ and Zn2+ are well immobilized. The preferential formation of Pb3(PO4)2 (Ksp = 8 × 10-43) and Zn3(PO4)2 (Ksp = 9.0 × 10-33) reduced the amount of MgKPO4·6H2O (Ksp = 2.4 × 10-11), resulting in a decrease in compressive strength. Besides, coexisting Pb2+ and Zn2+ has a competitive effect: Pb2+ will weaken the immobilization efficiency of Zn2+. The new exploration of these mechanisms provide a theoretical basis for rationally adjusting the Magnesia/Phosphate ratio to enhance the compressive strength and improve the efficiency of heavy metals immobilization.


Assuntos
Incineração/métodos , Chumbo/química , Zinco/química , Materiais de Construção , Íons , Magnésio , Compostos de Magnésio , Metais Pesados/química , Minerais/química , Fosfatos/química , Potássio , Compostos de Potássio , Esgotos/química
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