Municipal Incineration Fly Ash Research Articles

Achieving zero waste of municipal incinerator fly ash by melting in electric arc furnaces while steelmaking

The main objective of this work was to promote zero waste of municipal incinerator fly ash (MIFA) by full-scale melting in electric arc furnaces (EAFs) of steel mini mills around the world. MIFA, generally, is considered as a hazardous waste. Like in many countries, MIFA in Taiwan is first solidified/stabilized and then landfilled. Due to the scarcity of landfill space, the cost of landfilling increases markedly year by year in Taiwan. This paper presents satisfactory results of treating several hundred tons of MIFA in a full-scale steel mini mill using the approach of “melting MIFA while EAF steelmaking”, which is somewhat similar to “molten salt oxidation” process. It was found that this practice yielded many advantages such as (1) about 18wt% of quicklime requirement in EAF steelmaking can be substituted by the lime materials contained in MIFA; (2) MIFA would totally end up as a material in fractions of recyclable EAF dust, oxidized slag and reduced slag; (3) no waste is needed for landfilling; and (4) a capital cost saving through the employment of existing EAFs in steel mini mills instead of building new melting plants for the treatment of MIFA. Thus, it is technically feasible to achieve zero waste of MIFA by the practice of this innovative melting technology.

Seed Germination and Growth Parameters of (Zea mays L.) as influenced by Municipal Solid Waste Incineration Fly Ash (MSWIFA) and Sewage Sludge (SS) amended Soil.

Seed germination trials have relevance in measuring soil toxicity. As a consequence, this present work was carried out to investigate the effect of municipal solid waste incineration fly ash (MSWIFA) and sewage sludge (SS) from Phuket municipal waste incinerator and wastewater treatment plant as the fertilizer substitutes on the seed germination and growth parameters of sweet corn ( Zea mays L.). Field experiment was conducted at National Corn and Sorghum Research, Nakhon Ratchasima Province, Thailand in Randomized Complete Block Design (RCBD). The main treatments are 1) non-amended soil, 2) 378.125 kg MSWIFA ha -1 , 3) 543.75 kg SS ha -1 , 4) 756.25 kg MSWIFA ha -1 , 5) 1087.5 kg SS ha -1 , and 6) 378.125 kg MSWIFA ha -1 + 543.75 kg SS ha -1 . The results showed the different application rates of MSWIFA and SS had profound effects on plant establishment and growth characteristics relative to the fertilizer application. The highest germination index (22.26), vigor index (146.4), leaf numbers (5.65), and fresh and dry weight (5.78 and 2.35 g plant -1 , respectively) were recorded from seeds treated with SS (1087.5 kg ha -1 ), while the highest seed germination is found in F1M6 (378.125 kg MSWIFA ha -1 + 543.75 kg SS ha -1 ). This suggests the alternative use of MSWIFA and SS without the addition of fertilizer in agricultural land.

Production and Application of Synthetic Lightweight Aggregates Using Municipal Solid Waste Incinerator Fly Ash, Reservoir Sediment and Waste Glass Powder

Production and Application of Synthetic Lightweight Aggregates Using Municipal Solid Waste Incinerator Fly Ash, Reservoir Sediment and Waste Glass Powder

Properties of MSWI Fly Ash Slag-blended Cement Concrete

Municipal solid waste incinerator (MSWI) fly ash was melted into slag and then pulverized to generate particle sizes of less than 38 μm in diameter (sieve #400) for experimental studies. Several slag-blended cement concrete (SBCC) specimens 10 cm in diameter and 20 cm in height were molded using 20% cement replacement with slag powder. Then, three water/cementitious (w/c) ratios, namely 0.36, 0.52 and 0.68, were selected to test the specimens for slump, setting time, compressive strength and durability. The compressive strengths of specimens of various ages were compared with those of ordinary Portland cement concrete (OPCC) specimens. The results reveal that the compressive strengths of the SBCC specimens were lower than those of the OPCC specimens at an early stage and became similar to those of the OPCC specimens at the age of 28 days. Moreover, the compressive strengths of the SPCC specimens are 100-113% and 105-118% those of the OPCC specimens after 56 and 90 days, respectively. The slumps (i.e. workability) and setting times for both the SBCC and OPCC specimens were similar. Our test results show that MSWI slag-blended cement concrete is usable for practical applications and can be applied to the concrete pavement.

The effect of neutralization with carbon dioxide on leaching amounts of heavy metals from cement solidified waste of municipal incineration fly ash

The effect of neutralization with carbon dioxide on leaching amounts of heavy metals from cement solidified waste of municipal incineration fly ash

Reuse of cement-solidified municipal incinerator fly ash in cement mortars: Physico-mechanical and leaching characteristics

The reuse of cement-solidified Municipal Solid Waste Incinerator (MSWI) fly ash (solidified/stabilised (S/S) product) as an artificial aggregate in Portland cement mortars was investigated. The S/S product consisted of a mixture of 48 wt.% washed MSWI fly ash, 20 wt.% Portland cement and 32 wt.% water, aged for 365 days at 20 °C and 100% RH. Cement mortars (water/cement weight ratio = 0.62) were made with Portland cement, S/S product and natural sand at three replacement levels of sand with S/S product (0%, 10% and 50% by mass). After 28 days of curing at 20 °C and 100% RH, the mortar specimens were characterised for their physico-mechanical (porosity, compressive strength) and leaching behaviour. No retardation in strength development, relatively high compressive strengths (up to 36 N/mm 2) and low leaching rates of heavy metals (Cr, Cu, Pb and Zn) were always recorded. The leaching data from sequential leach tests on monolithic specimens were successfully elaborated with a pseudo-diffusional model including a chemical retardation factor related to the partial dissolution of contaminant.

06/02583 Electrodialytic removal of heavy metals from municipal solid waste incineration fly ash using ammonium citrate as assisting agentPedersen, A. J. et al. Journal of Hazardous Materials, 2005, 122, (1–2), 103–109

06/02583 Electrodialytic removal of heavy metals from municipal solid waste incineration fly ash using ammonium citrate as assisting agentPedersen, A. J. et al. Journal of Hazardous Materials, 2005, 122, (1–2), 103–109

UVA Photoirradiation of Halogenated-Polycyclic Aromatic Hydrocarbons Leading to Induction of Lipid Peroxidation

Since the finding in the 1930s, a large number of polycyclic aromatic hydrocarbons (PAHs) of different structures have been tested for potential tumorigenicity. Structure-activity relationships of halo-PAHs have been investigated to determine the regions of a PAH that may be involved in cancer initiation. From these studies, a number of halo-PAHs were found to be tumorigenic in experimental animals. It was not until the 1980s that halo- PAHs were found to be present in the environment, including municipal incinerator fly ash, urban air, coal combustion, soil, snow, automobile exhausts, and tap water. Due to their widespread presence in the environment and their genotoxic activities, including carcinogenicity, many of these compounds may pose a health risk to humans. Although the biological activities, including metabolism, mutagenicity, and carcinogenicity, of halo- PAHs have been studied their phototoxicity and photo-induced biological activity have not been well examined. In this study, we study the photoirradiation of a series of structure-related halo-PAHs by UVA light in the presence of a lipid, methyl linoleate, and determine as to whether or not these compounds can induce lipid peroxidation. The halo-PAHs chosen for study include 2-bromonaphthalene, 1-chloroanthracene, 9,10- dibromoanthracene, 9-chlorophenanthrene, 9-bromophenanthrene, 7-chlorobenz[a]anthracene, 7- bromobenz[a]anthracene, 7-bromo-5-methylbenz[a]anthracene, 6-chlorobenzo[a]pyrene, and 6- bromobenzo[a]pyrene. The results indicate that upon photoirradiation by UVA all these compounds induced lipid peroxidation at different levels. These results suggest that halo-PAHs may be harmful to human health.

Physical-mechanical and environmental properties of sintered municipal incinerator fly ash

A step-wise treatment of Municipal Solid Waste (MSW) incinerator fly ash including washing, milling and sintering was investigated in order to manufacture ceramic materials with improved physical, mechanical and environmental properties and, possibly, to reduce the power input of the sintering process. An interpretation of the test results based on the microstructure of sintered products and sintering kinetic modeling was also attempted to identify the densification mechanisms. It was found that milling of washed fly ash represents a basic step for manufacturing high-density ceramic materials with very high compressive strengths (up to 500 N/mm 2). A significant reduction in the power input of the sintering process (reduction of firing temperature from 1210 °C for washed fly ash to 1140 °C for milled-washed fly ash) is also achieved. A dense, well-sintered microstructure is formed through an intermediate-stage, liquid-phase sintering mechanism controlled by liquid-phase diffusion and grain shape accommodation. Such a microstructure is able to strongly immobilise heavy metals, thus giving good environmental properties to sintered product.

Extraction of metals from municipal solid waste incinerator fly ash by hydrothermal process

This work examined the extraction properties of metallic elements from municipal incinerator fly ash under hydrothermal conditions. The ash was firstly pre-washed by distilled water, then subjected to hydrothermal treatments. The pre-washing process was effective for Na, K, Ca extraction with extraction percentages of 67%, 76% and 48%, respectively. The optimum contact time was 30 min for the pre-washing process. Five types of acids were tested for the extraction experiments and hydrochloric acid was found to be most effective for metal extraction from the ash. Compared to room condition, hydrothermal treatment accelerated the dissolution of the ash, thus promoted the reaction of acid with hazardous metals such as Cr, Cd, Pb, and furthermore, the consumption speed of acid was slowed down under hydrothermal condition. The acid simultaneously reacted with all the metal in the ash under hydrothermal condition but preferentially reacted with Ca at room condition. The optimum hydrothermal treatment temperature, time and liquid/solid ratio were 150 °C, 5 h and 10:1 (ml:g), respectively.

Direct speciation of lead, zinc and antimony in fly ash from waste treatment facilities by XAFS spectroscopy

It is important to understand the chemical states of heavy metals in solid waste from municipal incinerator (MSWI) fly ash as both the toxicity and behavior in the environment of heavy metals differ with their chemical states. In this study, direct speciation of lead, antimony and zinc in MSWI fly ash was conducted by XAFS spectroscopy. Three kinds of fly ash from continuous stoker-type MSWIs and a kind of fly ash from an ash melting plant (AMP) were investigated. XAFS measurements were carried out on beam line BL01B1 at SPring-8. The lead, zinc and antimony spectra were collected in fluorescence detection mode at room temperature with a Si (111) or Si (311) monochromator. According to Pb LIII-edge XANES spectra, lead was estimated to be predominantly PbCl2 in MSWI fly ashes and PbO in AMP fly ash. Zinc was estimated to be speciated predominantly as ZnCl2 in MSWI fly ashes and a mixture of 2ZnCO3·Zn(OH)2, ZnO and ZnS in AMP fly ash. Antimony K-edge XANES spectra indicated that Sb is five-valent in all the fly ashes.

Effects of a washing pre-treatment of municipal solid waste incineration fly ash on the hydration behaviour and properties of ash–Portland cement mixtures

Effects of a washing pre-treatment of municipal solid waste incineration fly ash on the hydration behaviour and properties of ash–Portland cement mixtures

Optimisation d'un procédé de lixiviation en milieu basique et acide pour la décontamination (Cd, Pb) d'un mélange de cendres de chaudières et d'électrofiltres d'incinérateur de déchets municipaux

The purpose of this research was to improve a process for the removal of Cd and Pb from municipal incinerator fly ashes (boiler and electrofilter ashes). The first part of this study was to evaluate the optimum conditions for Pb extraction using alkaline washing steps. The tests carried out with various ash solid concentrations (10–50% (w/v)) have shown better Pb removal yields following the decrease of the solid concentrations. Nevertheless, by considering the economic aspect, a ratio of 30% (w/v) was retained as the optimal condition for alkaline leaching steps. A very short contact time (2 min) allows a maximum lead solubilization during alkaline washings. A series of two or three alkaline washing steps is necessary for sufficient lead removal. Once the alkaline leaching conditions have been optimized, research was applied to identify the optimum conditions of acid leaching. Best Pb and Cd removal yields of 25% and 85%, respectively, have been obtained by using two 30-min washing steps at pH 3 with a pulp density of 10% (w/v). The treated ashes respect the TCLP criteria. Finally, the adapted process of ash treatment presented in this study allows a substantial reduction of 57% of the chemical costs compared with the conventional procedure, and a significant reduction (83%) of water consumption. Key words: cadmium, lead, fly ash, alkaline leaching, acid leaching, removal, TCLP, decontamination.

Solidification of municipal solid waste incineration fly ash with cement and its leaching behaviors of heavy metals

The solidifying effect of cement addition on municipal solid waste incineration fly ash (MSWFA for short, collected from the gas exhaust system of MSW incinerator), the interaction of MSWFA with cement and water and the leaching of heavy metals from cement-solidified MSWFA are investigated. The main results show that: (1) when MSWFA is mixed with cement and water, H2 evolution, the formation and volume expansion of AFt will take place, the volume expansion can be reduced by ground rice husk ash addition; (2) heavy metals do leach from cement-solidified MSWFA and at lower pH more leaching will occur; (3) compared with cement—solidified fly ash, the leachate of solidified MSWFA is with higher heavy metal contents; (4) with the increment of cement addition leached heavy metals are decreased; and (5) concentrations of Zn, Mn, Cu and Cd in all the leachates can meet the relevant Standards of Japan, but as the regulations for soil and groundwater protection of Japan are concerned, precautions against the leaching of Pb, Cl− and Cr6+ and so on are needed.

Synthesis of Zeolite from Municipal Incinerator Fly Ash by Addition of Water Glass

Synthesis of Zeolite from Municipal Incinerator Fly Ash by Addition of Water Glass

Récupération du Plomb et du Zinc par Adsorption sur Tourbe Lors de La Décontamination de Chaux Usées D'incinérateur de Déchets Municipaux Lead and Zinc Recovery by Adsorption on Peat Moss During Municipal Incinerator Used Lime Decontamination

The objective of this research was to evaluate the efficiency of peat moss for lead and Zn recovery from alkaline leachates (pH 11.5) produced during decontamination of municipal incinerator fly ash. Tests carried out with peat moss columns (density of 0.13 g m l−1) gave very high removal yields for lead (98.9 to 100 %) and Zn (98.4 to 99.8 %). The initial metal concentrations in the leachates were 126 to 138 mg Pb l−1 and 14.4 to 23.5 mg Zn l−1. The columns were fed using two rates (20 and 40 ml min−1), which correspond respectively to 17.6 and 8.8 min as contact time on peat moss. Adsorption efficiencies of 16 to 18 mg Pb g−1 and 1.7 to 3.2 mg Zn g−1 have been measured during this fly ash leachate treatment study. The adsorbed toxic metals can be desorbed using a chlorhydric acid solution. The peat moss can be regenerated and reused for several adsorption cycles without loss of the lead and Zn adsorption efficiencies.

Investigation of hydrogen generation from municipal solid waste incineration fly ash

Hydrogen generation from municipal solid waste incineration fly ash was investigated to understand the influences of contacting method, kinds of contact solution, liquid to solid ratio, and particle size distribution of materials. Redox properties of materials and hydrogen generation were also studied. The largest quantity of gas generated in contact with water was 29.1 ml/g-ash, most of which was hydrogen. Fluidized bed fly ash generated more gas than stoker fly ash. In order to calculate the hydrogen generation potential (the maximum quantity of gas generated in contact with water), a novel system using a Y-shaped test tube and NaOH was utilized. This method gives values which are related to the quantity of generated gas in contact with water. A relationship between the aluminum content and hydrogen generation potential was observed, especially for fluidized bed fly ash. The reducing potential of fluidized bed fly ash was higher than that of stoker fly ash. Only fluidized bed fly ash showed a positive correlation between aluminum content and reducing potential, and between reducing potential and hydrogen generation potential. These results suggest that fluidized bed fly ash contains more Al0 than stoker fly ash.

99/03980 Phosphorus removal by fly ash: Ugurlu, A. and Salman, B. Environ. Int., 1998, 24, (8), 911–918

The extractability of heavy metals (Pb, Cd, Cr and Cu) from a municipal incinerator fly ash (designated MIFA S) using an acidic or basic extractant and their subsequent recovery by electrowinning using an electrolytic cell of the fluidized-bed type was investigated. The extractants studied were HCl, HNO3, H2SO4, HOAc, NaOAc (pH=8.15), and NaOAc (pH=3) having 0.1 N in concentration. Of which, NaOAc (pH=3) outperformed the others and was selected for further studies. A 24-1 fractional factorial experimental design was adopted using liquid-to-solid (L/S) ratio, extractant concentration, extraction time, and initial pH as the experimental factors. The results show that L/S and extraction time played an important role in Pb extraction while L/S ratio and extractant concentration were important for Cr extraction. However, no controlling parameter was determined for Cd extraction, but a lower extraction efficiency was obtained if an initial pH of greater than 5 was used. For the study of electrolytic recovery, the experiments were carried out based on a 23-1 fractional factorial design using current density, initial pH, and operating temperature as the experimental factors. It was determined that current density was important to electrolytic recovery of Pb and Cu, but with an opposite effect. The other two experimental factors were insignificant, 96.70% of Pb and 93.69% of Cu were recovered from the leachate of MIFA S when 0.4 A-h of electrical charge was applied. The results obtained suggest that the recovery of heavy metals from MIFA S by solvent extraction and electrolytic recovery is technically feasible.

Long-term leaching mechanisms of Portland cement-stabilized municipal solid waste fly ash in carbonated water

A leach test is described and applied to municipal incinerator fly ash (10%) stabilized in Portland cement. The test differs from previous tests mainly by bubbling CO 2 through the leachant, which itself is periodically renewed. An advantage of the test is that pH remains nearly constant at 6.5 to 6.8 throughout the test duration. The results of leach tests are correlated with microstructural studies of the leached layer, which reaches a depth of ∼800 μm in 214 days. Development of a complex zonal structure gives a semiprotective surface layer. If the initial slope of the leaching curve as a function of time 1/2 is prolonged, experimental results fall well below this extrapolated curve as leaching times increase beyond >100 to 200 h. Important changes occur in leach mechanisms at about this time, and the predictive accuracy of short-term accelerated tests, particularly when pH is not stabilized, is questioned.

Microstructural characterisation of a glass and a glass-ceramic obtained from municipal incinerator fly ash

Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analyses were used to characterise the microstructure and chemical composition of a glass and a glass-ceramic material obtained from incinerator filter fly ash. Although the as-quenched material (vitrified fly ash) was amorphous under the detection limits of XRD, a dispersion of droplets indicating glass-in-glass phase separation was observed. In the glass-ceramic material (crystallised vitrified fly ash), crystals belonging to the pyroxene group and spinels were identified. The microstructure of the glass-ceramic consisted of crystals embedded in an amorphous glassy phase. The crystalline phases contain a higher amount of metallic elements (e.g. Al, Cr, Fe, Ni and Zn and most probably also other heavy metals) than the residual glassy phase. A change of composition of the residual glass phase in the glass-ceramic product, in comparison with the parent glass, is considered to explain, in comparative terms, the higher toxic potential of the glass-ceramic over the glass. The present results demonstrate that for an accurate assessment of the correlation between toxicity, release of hazardous compounds and microstructure, high-resolution characterisation techniques must be employed. In this context, the effect of crystallisation on the chemical durability of the products remains as an important area for further research.