Waste Incineration Ash Research Articles

Ash formation and the inherent heavy metal partitioning behavior in a 100 t/d hazardous waste incineration plant

Hazardous waste incineration (HWI) ash is also defined as hazardous waste and its disposal performance depends largely on the ash compositions as well as the potential environmental risk of heavy metals. In this work, HWI ashes of four sampling sites were collected in a 100 t/d hazardous waste incineration plant with rotary kiln over three consecutive days. The formation characteristics of ash samples including heavy metal partitioning were given, with further discussions on the melting disposal of HWI ash mixtures. Results showed significant differences in the ash compositions among the sampling sites. Caused by NaHCO3 injection as de-acidizing adsorbent, the sum of Na, S and Cl content in bag filter ash even exceeded 70%. Cu/Mn/Cr tended to transfer into the bottom ash due to low volatilities, while Zn/Pb/Cd/Se/As were more likely to be enriched in the ash particles. In particular, chemical adsorption at medium- to high- temperature range was dominant for As enrichment in the waste heat boiler ash. Despite the complexity and diversity of raw hazardous wastes, little difference was found in the melting temperature of bottom ash during the sampling period. However, it could vary by more than 200 °C for fly ash due to the fluctuation of alkali components in raw wastes. Moreover, slagging medium was encouraged in order to achieve rapid and complete melting of ash mixtures. The objective of this study is to gain knowledge on the HWI ash formation and inherent heavy metal partitioning behavior, expecting to provide guidelines on the deep harmless disposal of HWI ash in future.

Geochemistry of the Dust Collected by Passive Samplers as a Tool for Search of Pollution Sources: The Case of Klaipėda Port, Lithuania

Geochemical investigations of total suspended particulates (TSP) help detect hotspots and emission sources in port cities with stevedoring operations. The aim was to reveal these sources via geochemical indices (gI). TSP were collected in Klaipėda using original passive samplers in ten sites during four periods, during one of them, in ten additional sites near iron ore stevedoring (IOS). The contents of 22 elements (PHEs, crustal, Br, Cl) were determined by EDXRF in TSP and characteristic dust (CD) of stevedored iron ore, apatite, phosphorite, potassium fertilizers, and in waste incineration ash. Median Fe content in TSP near IOS was ~29%. The significant anthropogenic origin of clusters Fe–Cr, Sr–P, V–Ni–Zn–Cu, Pb–As, and Mg–Ca, Br–S–Cl was confirmed by gI mapping and analysis of CD. Significant temporal variability of Cl, S, Sr, Ni, Br, V, and Zn due to weather changes was revealed. Near IOS, significantly higher values of gI were found for Fe and Cr, while far from IOS, for K, Sr, Ti, Rb, Cu, Al, Si, Zr, Ca, Mg. Significantly higher values of normalized enrichment factor near IOS were not only for Fe and Cr, but also for As, Pb, S, Mn, Br, and Cl.

Mesoporous Silica Derived from Municipal Solid Waste Incinerator (MSWI) Ash Slag: Synthesis, Characterization and Use as Supports for Au(III) Recovery.

In this study, the effect of NaOH on the synthesis of mesoporous silica (MS) by using municipal solid-waste incinerator (MSWI) ash slag was investigated. Moreover, the prepared MS was used as a support to evaluate its potential for the recovery of gold ions (Au(III)) from aqueous solution. The extraction process for the MSWI ash slag activated through mechanical grinding entailed alkali treatment, using varying concentrations of NaOH. The content of Si extracted from MSWI ash slag increased with the increasing grinding time and NaOH concentration. As the NaOH concentration increased, the pore structure (e.g., Brunauer–Emmett–Teller (BET) surface area and pore volume) of the synthesized MS improved. In addition, the amount of adsorbed Au(III) increased with increasing sulfur content immobilized on the support, and the sulfur content was in turn governed by the silanol content of the MS support. The adsorbent prepared by using the MS-3M support exhibited the highest Au(III) adsorption capacity (110.3 mg/g), and its adsorption–desorption efficiency was not significantly affected even after five adsorption–desorption cycles.

Kinetics of the High Temperature Oxidation of the Inconel 686 Coatings in the Waste Incineration Ash

Kinetics of the High Temperature Oxidation of the Inconel 686 Coatings in the Waste Incineration Ash

The chemical and physical origin of incineration ash reactivity in cementitious systems

Municipal solid waste incineration (MSWI) ashes are byproducts of the combustion process at a waste-to-energy facility, often destined for the landfill. These ashes can be compositionally comparable to ordinary Portland cement, blast furnace slag, and coal fly ash. However, these ashes are largely unutilized as a supplementary cementitious material as their effect on cementitious systems is not well understood. This lack of understanding is primarily due to the elemental and mineralogical complexity of these ashes. To solve this problem, here we have analyzed the hydration behavior of ordinary Portland cement blended with 8 distinct and diverse MSWI ashes. Our results indicate that incorporating these MSWI ashes can either accelerate or retard cement hydration depending upon their composition. Specifically, Cu, Fe, Al, Ti, Si, K, Zn, and Sr from the MSWI ash matrix appear to retard cement hydration, while Pb, Br, S, Ca, and Cl appear to accelerate cement hydration. Based on these results, we introduce a new parameter - Incineration Ash Coefficient (IAC) - which correlates with the 7-day compressive strength of mortars incorporating MSWI ashes reasonably well (R2= 0.79). This new parameter, based on fundamental chemical and physical characteristics of ashes, is the first step towards effective screening and employment of MSWI ashes as cementitious materials.

Municipal Solid Waste Incineration Ash-Incorporated Concrete: One Step towards Environmental Justice

Municipal solid waste and cement manufacture are two sources of environmental justice issues in urban and suburban areas. Waste utilization is an attractive alternative to disposal for eliminating environmental injustice, reducing potential hazards, and improving urban sustainability. The re-use and recycling of municipal solid waste incineration (MSWI) ash in the construction industry has drawn significant attention. Incorporating MSWI ash in cement and concrete production is a potential path that mitigates the environmental justice issues in waste management and the construction industry. This paper presents a critical overview of the pretreatment methods that optimize MSWI ash utilization in cement/concrete and the influences of MSWI ash on the performance of cement/concrete. This review aims to elucidate the potential advantages and limitations associated with the use of MSWI ash for producing cement clinker, alternative binder (e.g., alkali-activated material), cement substitutes, and aggregates. A brief overview of the generation and characteristics of MSWI ash is reported, accompanied by identifying opportunities for the use of MSWI ash-incorporated products in industrial-scale applications and recognizing associated environmental justice implications.

Stabilization of Expansive Soil Using Biomedical Waste Incinerator Ash

Expansive soils undergo high volume change due to cyclic swelling and shrinkage behavior during the wet and dry seasons. Thus, such problematic soils should be completely avoided or properly treated when encountered as subgrade materials. In the present study, the biomedical waste incinerator ash and lime combination was proposed to stabilize expansive soil. Particle size analysis, Atterberg limits, free-swell, compaction, unconfined compression strength, and California bearing ratio tests were conducted on the natural soil and blended with 3%, 5%, 7%, 9%, and 11% biomedical waste incinerator ash (BWIA). The optimum content of BWIA was determined based on the free-swell test results. To further investigate the relative effectiveness of the stabilizer, 2% and 3% lime were also added to the optimum soil-BWIA mixture and UCS and CBR tests were also conducted. In addition, scanning electron microscopy (SEM) tests for representative stabilized samples were also conducted to examine the changes in microfabrics and structural arrangements due to bonding. The addition of BWIA has a promising effect on the index properties and strength of the expansive soil. The strength of the expansive soil significantly increased when it was blended with the optimum content of BWIA amended by 2% and 3% lime.

Stabilizing black cotton soil in subgrade with municipal solid waste incineration ash for lowering greenhouse gas emission: A review

The construction of bituminous pavement causes greenhouse gas emissions which can be reduced significantly by using municipal solid waste incineration (MSWI) ash in the subgrade. The present study is the review of work carried out by various researchers on the improvement of engineering properties of expansive soils, namely black cotton soil (BCS), after the addition of MSWI ash to the soil in varying proportions. The study findings indicate that the optimum content of MSWI ash to be added to expansive soils for improvement in strength characteristics varies between 10% and 30%, with the best results at 25% of MSWI ash proportion. This content of MSWI ash increases the unconfined compressive strength (UCS) of expansive black cotton soil from 28.8 kPa to 53.4 kPa and an increase in CBR value from 3.38% to 9.38%. Therefore, the review suggests using MSWI ash, keeping in view the enormous increase in volumes of municipal solid waste (MSW) due to fast urbanization in the country. Most of the past studies on soil stabilization through ashes are based on ashes of thermal power projects. Still, the present research focuses on using MSWI ash for the dual purpose of stabilization of black cotton soil to be used as subgrade material and to minimize greenhouse emissions. This is the novelty of the present study.

Geotechnical characteristics of clayey soil admixed with municipal solid waste incineration ash, cement and polypropylene fiber

Geotechnical characteristics of clayey soil admixed with municipal solid waste incineration ash, cement and polypropylene fiber

Porous alkali-activated materials based on municipal solid waste incineration ash with addition of phosphogypsum powder

This is a study of municipal solid waste (MSWI) ash from the Lithuanian incinerator, which was used as an aluminosilicate precursor and pore-forming agent for the production of porous alkali-activated materials. The relationships between the density, pore size, pore distribution, compressive strength, mineral composition, thermal conductivity, and incorporation of phosphogypsum (PG) and/or hydrogen peroxide were observed. It was found that the porous materials had density in the range of 833 kg/m3 − 1345 kg/m3, compressive strength was in the range of 1.5 MPa − 4.1 MPa and thermal conductivity varied in the range of 0.23 W/(m⋅K) − 0.39 W/(m⋅K). The additional pore forming agent hydrogen peroxide with PG has a positive effect on the formation of small pores in the alkali-activated MSWI ash system. In this case, without PG, the number of large pores increased due to coalescence. The addition of PG acted as a binding accelerator of the alkali-activated system and this resulted in the formation of a large number of small and medium sized pores. The prepared porous alkali-activated MSWI ash had the best results with the incorporation of 15% phosphogypsum. In this case, the samples had a compressive strength of 1.8 MPa, the density reached 900 kg/m3 and the thermal conductivity was 0.23 W/(m⋅K).

The leaching potential of sewage sludge and municipal waste incineration ashes in terms of landfill safety and potential reuse

Incinerations residues from different types of materials (sewage sludge incineration ash and municipal waste incineration ashes) can either be by-products used in industry, or can pose a serious environmental problem related to their composition and the presence of potentially hazardous elements. State regulations and standards indicate whether material is inert, non-hazardous or hazardous. These standards, however, do not provide a complete overview on the leaching behavior of potentially hazardous elements in the environment. This study presents the result of batch experiment performed in accordance with the PN-EN 12457-2 (2006) and PN-EN 12457-4 (2006) standards. The results indicated that the leachability of elements is strongly dependent on the mineral composition of the waste product (the concentration and composition of soluble phase), the chemical composition (the mobility of hazardous elements and their affinity to soluble minerals), and the pH. To ensure environmental safety a thorough characterization of the waste is required followed by qualitative assignment to a particular waste type based on available guidance. Furthermore, to avoid leaching of potentially harmful elements into soils or surface water, it is also paramount to perform environmental impact assessment of wastes used as by-product in industry e.g., as building or road construction materials (aggregate) and fertilizers.

Application of Statistical Methods in Predicting the Properties of Glass-Ceramic Materials Obtained from Inorganic Solid Waste.

This paper uses mathematical methods as the basic tool at the stage of experiment planning. The importance of research programming applications was shown using the theory of experiments and the STATISTICA software. The method of experiment planning used in the case of studying the properties of a mixture, depending on its composition, features considerable complexity. The aim of the statistical analysis was to determine the influence of variable chemical composition of waste materials on selected properties of glass-ceramic materials. A statistical approach to multicomponent systems, such as ceramic sets, enables the selection of appropriate amounts of raw materials through the application of ‘a plan for mixtures’. To utilize the raw waste materials, e.g., slags from a solid waste incinerator, fly or bottom ashes, in the modeling of new materials, a mathematical relationship was developed, which enables estimating, based on the waste chemical composition, selected technological and practical properties of the glass so as to obtain a material featuring the required technological–practical parameters. For the obtained glasses, a comparative analysis of the experimentally and computationally determined properties was carried out: transformation temperature, liquidus temperature, density, and thermal expansion coefficient. The obtained high theoretical approximation (at the level of determination correlation coefficient R2 > 0.8) confirms the suitability of the polynomial model for mixtures for applications in the design of new glass-ceramic products.

Recycling of Waste Incineration Bottom Ash and Heavy Metal Immobilization by Geopolymer Production

Municipal waste incineration ash contains heavy metals, and the safety of its disposal and reuse is an important issue. In this study, we discussed a safe recycling technology for bottom ash (BA) by utilizing the excellent heavy metal immobilization feature of geopolymer (GP). First, the differences in chemical compositions, physical properties, and heavy metal contents of BAs discharged in different months were investigated. Next, the reaction products and strength of the mixture of BA and alkali-activator (AA) solution were examined to clarify the reactivity of BA in the AA solution. We also investigated the effects of the discharge time of BA, ingredients of AA solution, curing method and mixing ratio of BFS on the setting time, strength and heavy metal immobilization capacity of GP mortar using ground granulated blast furnace slag (BFS) and coal fly ash (CFA) as precursors, and BA as fine aggregate, and discussed reaction products and micro-structure of the GP mortar. The main results are as follows: 1) BA contained a small amount of amorphous phase. Hardened GP monolith using BA and AA solution was not dense and had a very low strength. 2) The BFS/CFA-based GP mortar with BA as fine aggregate had a higher strength and a longer setting time when sodium silicate solution (WG) was used as AA solution than when sodium hydroxide was added or used entirely. The GP mortars using the BAs discharged in the warm season had longer setting time and higher strength. The reaction products of the GP mortar with WG solution and BA were mainly C-A-S-H gels. The leaching of heavy metal elements (HME) from the GP mortars increased with decreasing the alkalinity of leachate, but the effect of BA’s discharge season was not found in this study. The HME leaching concentrations from the GP mortars in non-acidic water environment were less than the HME leaching limits specified for recycled construction materials directly contacting with water, thus the GP materials with BA can be used in dry or non-acidic water environment. However, when used in acidic water environment, the BA content in the GP materials should be reduced.

Comparison of trace element mobility from MSWI ash before and after plasma vitrification.

A common perception of plasma arc treatment systems for municipal solid waste incineration ash is that the resulting vitrified slag is inert from an environmental perspective. Research was conducted to examine this hypothesis and to assess whether reduced pollutant release results from pollutant depletion during the process of the ash with plasma, or encapsulation in the glassy vitrified matrix. The concentrations of four discrete municipal solid waste incineration ash samples before and after plasma arc vitrification in a bench-scale unit were compared. Slag and untreated ash samples were leached using several standardized approaches and mobility among the four metals of interest (e.g. As, Cd, Pb and Sb) varied across samples, but was generally high (as high as 100% for Cd). Comparison across methods did not indicate substantial encapsulation in the vitrified slag, which suggests that reduced pollutant release from plasma arc vitrified slag is due to pollutant depletion by volatilization, not encapsulation. This has significant implications for the management of air pollution control residues from waste-to-energy facilities using plasma arc vitrification.

Enhancing the Engineering Properties of Indian Black Cotton Soil with Municipal Solid Waste Incineration Ash – A Review

The present study is the review of work carried out by various researchers on the improvement of engineering properties of expansive soils namely Indian Black Cotton Soil (BCS), after the addition of MSWI ash to the soil in varying proportions. The findings of study indicate that the optimum content of MSWI ash to be added to expansive soils for improvement in strength characteristics varies between 10% and 30% with best results at 25% of MSWI ash proportion. This content of MSWI ash increases the UCS of expansive black cotton soil from 28.8 kPa to 53.4 kPa and an increase in CBR value from 3.38% to 9.38%. The review suggests the use of MSWI ash in India keeping in view the enormous increase in volumes of municipal solid waste (MSW) due to fast urbanization in the country. The extensive use of such green technology will go a long way in reducing requirement of civil construction materials thereby lowering greenhouse emissions. Simultaneously, cost effectiveness in improvement of weak soils to be used in Highway subgrade civil engineering applications using MSWI ash will result is sustainable construction practices.

Washed waste incineration bottom ash as a raw ingredient in cement production: Implications for lab-scale clinker behavior

Municipal solid waste incinerator (MSWI) ash has a similar chemical composition to traditional cement kiln feed components, making it a potentially viable replacement for traditional materials in the absence of deleterious components invariably present in ash. This supposition should be confirmed by lab-scale experimentation prior to full-scale implementation. This study explores lab-scale cement manufacturing using varying replacement percentages of unwashed and water-washed MSWI bottom ash. The use of unwashed MSWI ash as a kiln feed is associated with a considerable decrease in tricalcium silicate content. Each replacement percentage of washed bottom ash incorporation resulted in an approximate tricalcium silicate content of 45%, while unwashed bottom ash specimens had tricalcium silicate contents of approximately 35%. Aluminate concentrations in ash-amended clinkers were considerably higher than reference clinkers, which may require additional gypsum to ensure proper setting. The effects of mineralogical differences were reflected in cement reactivity. Unwashed MSWI ash-amended specimens should be monitored for chloride and alkali content. Results of this study highlight the simultaneous impact of washed and unwashed MSWI bottom ash addition as kiln feed on clinker formation, and the special considerations for clinker production and behavior. The addition of MSWI ash as cement kiln feed is beneficial provided it is washed and appropriately controlled below 8% to reduce deleterious phase composition.

The Carbon Dioxide Emissions Reduction Potential of Carbon-Dioxide-Cured Alternative Binder Concrete

Climate change has been identified as one of the biggest issues plaguing human life at present. Hence, immense attention is being paid to developing methods that can potentially reduce carbon dioxide emission. With the help of carbon-negative concrete, manufactured from alternative binders and cured with waste carbon dioxide, a major part of the manufacturing industries that emit carbon dioxide can be potentially turned into a carbon sink. In this study, the waste material streams in Finland, suitable for disposing carbon-dioxide-cured concrete, were mapped. Mine tailings, blast furnace and steel slags, recycled concrete, biomass, coal and municipal waste incineration ashes, green liquor dregs, and foundry sands were studied. It was found that there were sufficient amounts of potential secondary raw materials (about 27 Mt/a) for the preparation of Finnish cement and the production of concrete (requirement: approximately 1.4 Mt/a and 11.2 Mt/a, respectively). The total carbon dioxide uptake potential was estimated to be approximately 1.9 Mt/a (vs. emissions from the cement industry in Finland, 0.84 Mt/a). In addition, the carbon footprints of the conventionally manufactured concrete block were compared with the carbon footprint produced by a modeled carbon-dioxide-cured blast furnace slag block. If such novel concrete were used to produce all the concrete-based substances, it would bring down the emission of carbon dioxide from 1.9% to negative 1.3% in Finland.

Sub-grade characteristics of clayey soil incorporating municipal solid waste incineration ash and marble dust

PurposeThe purpose of this paper is to use the waste materials in soil stabilization and low traffic volume roads so as to minimize the cost of subgrades for road construction along with solving disposal problems of waste materials thus protecting the environment.Design/methodology/approachAn extensive laboratory study has been carried out on various samples of soil alone and along with waste materials such as municipal solid waste incineration ash and marble dust by adding cement to evaluate their effect on geotechnical characteristics of clayey soils.FindingsThe experimental study revealed that mixture of soil:Municipal solid waste incineration ash (MSWIA):Cement and soil:Marble dust (MD):Cement can be successfully used for the construction of low traffic volume roads. The differential free swell of the clayey soil is nil on adding MSWIA: cement and MD: cement to clayey soil in optimum amounts.Research limitations/implicationsThe research needs further experimentation on combining both MSWIA and MD together to stabilize clayey soil.Practical implicationsThe research can be successfully used by government agencies in subgrades of low traffic roads.Social implicationsThe utilization of waste materials in the study solved the disposal problem of both waste materials, thus protecting the environment and giving quality living standards to people.Originality/valueThe use of MSWIA along with cement and use of MD along with cement for evaluating geotechnical properties has not been studied in the past. The present study is focussed on the use of both these materials along with cement in soil stabilization.

A study on the physical and chemical parameters of industrial by-products ashes useful in making sustainable concrete

Abstract With the rising population all over the world, industrial wastes have risen significantly which poses difficulty in disposing them without harming the surrounding ecosystem due to shortage of land. Hence as an alternative to disposal, some of these harmful industrial wastes can be reused and recycled in the construction industry ultimately protecting the environment from potential hazards. Out of various industrial by-products, some of the materials in the form of ashes can be utilized, replacing cement or sand thereby reducing the overall consumption of conventional building materials and also enhancing the concrete properties. In this study, five different types of industrial by-products ashes are reviewed which are coal fly ash, bottom ash, municipal solid waste incinerator ash, rice husk ash, and wood ash. The effects of physical and chemical parameters of these ashes on the strength characteristics of concrete if used as a cement or sand substitution have been analyzed.

Recycling Fly Ash from MSWI for Artificial Aggregate Production for Concrete

This study focusses on the development of new lightweight aggregate (LWA) that eventually will have comparable properties with existing natural aggregate which is granite. The main objectives of this study is to examine potential use of recycled municipal solid waste incineration (MSWI) ash as raw material in LWA production with a method of cold-bonded palletization process. The ashes are collected from Cameron Highland Incineration Plant, Malaysia that can be divided into bottom ash (BA) and fly ash (FA). This study uses FA as partial raw material to substitute the Ordinary Portland Cement (OPC). The properties FA are studied by means of X-Ray Fluorescence (XRF). The LWA is fly ash lightweight aggregate (FALA). The production of LWA is based on cold-bonded palletization technique. FALA have experienced two different curing process for 28 days namely room-room (RR) and room-water (RW) curing conditions. The percentage of FA used in this study is 10%, 20%, 30%, 40% and 50% of cement replacement and the size is fixed between 10 mm to 20 mm with circular shape. The properties of FALA produced in this study is examined including loose bulk density, and aggregate impact value (AIV). Other physical properties including colour and texture are also being investigated. From the results of LWA it is clearly seen that 20% FA were the best percentage of ash used to produce good quality LWA. Loose bulk density of FALA selected is 716.72 kg/m3 and AIV 13.80%.