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Wei W, Liu Q, Zhang Z, Lisak G, Yin K, Fei X. Categorization of leaching behaviors of elements from commercially treated incineration bottom ash in Singapore. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 178:339-350. [PMID: 38430748 DOI: 10.1016/j.wasman.2024.02.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 02/24/2024] [Accepted: 02/25/2024] [Indexed: 03/05/2024]
Abstract
Leaching of potentially hazardous substances, especially the heavy metals from Incineration Bottom Ash (IBA) is a major problem in its recyclable usage. To address this concern, treatment of IBA is indispensable before it can be reused. IBA subjected to laboratory-scale treatment typically yields clearer conclusions in terms of leaching behaviors, benefiting from the controlled laboratory environment. However, the leaching behaviors of commercially treated IBA appear to be more ambiguous due to the complex and comprehensive nature of industrial-scale treatments, where multiple treatment techniques are involved concurrently. Furthermore, treatment efficiencies vary among different plants. In this study, three types of commercially treated IBA were sampled from leading waste treatment companies in Singapore. Characterization and leaching tests were performed on the treated IBAs in both standardized and modified manners to simulate various scenarios. Besides deionized water, artificial seawater was used as a leachant in leaching tests for simulating seawater intrusion. The results reveal the promoting effect of seawater on the leaching levels of several elements from three types of treated IBA, which may require special attention for IBA application and landfill near the coast. Furthermore, the elements examined in these three types of commercially treated IBA generally comply with the non-hazardous waste acceptance criteria outlined in Council Decision, 2003/33/EC (2003), except Sb. By combining two leaching tests, the elements were categorized into different types of leaching behavior, making it possible to prepare and respond to the concerning leaching scenarios in future engineering applications.
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Affiliation(s)
- Wei Wei
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, 1 Cleantech Loop, 637141, Singapore
| | - Qian Liu
- Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, 1 Cleantech Loop, 637141, Singapore
| | - Zhibo Zhang
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Grzegorz Lisak
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, 1 Cleantech Loop, 637141, Singapore
| | - Ke Yin
- School of Biology and the Environment, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China
| | - Xunchang Fei
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, 1 Cleantech Loop, 637141, Singapore.
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Zhao S, Zhang S, Liang X, Li J, Liu C, Ji F, Sun Z. Transformation and environmental chemical characteristics of hazardous trace elements in an 800 t/d waste incineration thermal power plant. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170693. [PMID: 38325472 DOI: 10.1016/j.scitotenv.2024.170693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/17/2024] [Accepted: 02/02/2024] [Indexed: 02/09/2024]
Abstract
The hazardous trace elements (HTEs) emitted during the municipal solid waste incineration (MSWI) process have been widely concerned. In this work, the bottom ash (BA), heat recovery boiler ash (HA), and ash after desulfurization (SA) were collected to explore the occurrence forms of HTEs in the three types of ash and their relationship with minerals and leaching characteristics. The results show that the volatility of the seven studied HTEs follows the order of Cd, As > Ni, Zn > Pb > Cr, Cu. In the process of BA → HA → SA, the content of Cd, As, Zn, and Pb shows an increasing trend. The seven HTEs are mainly in the forms of chlorides and oxides. There is an obvious relationship between the occurrence forms and simulated existence form of HTEs. SiO2 and CaCO3 are the major mineral components in the three ashes, while SA also contains chlorine-containing compounds which are easily leached out. The risk assessment code and soluble ratio show that HTEs in SA are more leachable than BA and HA, where Cd, Pb and Ni need to be addressed to reduce their impact on soil or water during subsequent landfill treatment of SA.
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Affiliation(s)
- Shilin Zhao
- School of Energy Science and Engineering, Central South University, Changsha 410083, China; Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China
| | - Siqi Zhang
- School of Energy Science and Engineering, Central South University, Changsha 410083, China
| | - Xin Liang
- 3rd Construstion Co., Ltd. of China Construction 5th Engineering Bureau, Changsha 410004, China
| | - Jian Li
- Special Equipment Safety Supervision Inspection Institute of Jiangsu Province, Nanjing 210036, China
| | - Cheng Liu
- School of Energy Science and Engineering, Central South University, Changsha 410083, China
| | - Fu Ji
- School of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhiqiang Sun
- School of Energy Science and Engineering, Central South University, Changsha 410083, China.
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3
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Impact of Natural Weathering on Stabilization of Heavy Metals (Cu, Zn, and Pb) in MSWI Bottom Ash. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12073419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bottom ash (BA) is the main residue left by municipal solid waste incineration (MSWI). As the circular economy is strengthened, the use of BA in civil engineering is increasing, but its successful use is hampered by heavy metal leaching. In this study, we investigated the influence of natural weathering (6 months) on the stabilization of heavy metals (Cu, Zn, and Pb) with different particle sizes in MSWI BA. Natural weathering is the most popular and cost-effective treatment method for BA. During this process, calcium carbonate (CaCO3) is produced, which causes a reduction in heavy metal leaching. We used the following methods in the analysis: The fractionation of BA, XRF, and XRD; an extraction test (LST EN 12457-2:2003); and AAS. The results showed that the concentrations of all elements in BA decreased during natural weathering. An analysis of the mineralogical composition showed a very high (>20%) content of calcium carbonate (CaCO3). The calcium carbonate content increased by 3.2% during weathering because the Ca(OH)2 in fractions <5.6 mm and <40.0 mm was hydrolyzed to CaCO3. Our analysis showed that the metal concentrations (Cu and Pb) in untreated MSWI bottom ash eluate exceeded the limit values, and thus it cannot be used in civil engineering. After three months of stabilization, the heavy metal concentrations were less than the limit values.
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Li W, Gu K, Yu Q, Sun Y, Wang Y, Xin M, Bian R, Wang H, Wang YN, Zhang D. Leaching behavior and environmental risk assessment of toxic metals in municipal solid waste incineration fly ash exposed to mature landfill leachate environment. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 120:68-75. [PMID: 33285375 DOI: 10.1016/j.wasman.2020.11.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/31/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
Solidification/stabilization pretreatment + landfill disposal in municipal solid waste (MSW) landfill sites is a widely accepted MSW incineration (MSWI) fly ash (FA) management strategy in China. However, in reality, the stability of FA disposed in MSW landfill sites may be affected by the organic landfill leachate environment. The purpose of this study was to explore the mobility and environmental risks of six toxic metals (Mn+, Pb/Zn/Cu/Cd/Cr/Ni), from raw and solidified/stabilized FA, by simulating a leaching environment with mature landfill leachate (MLL). The leaching of Mn+ mainly occurred in the early leaching stage, and their leaching behavior was controlled by the diffusion of surface Mn+ in the FA matrix. The destructive effect of dissolved organic matter (DOM) on the local precipitation-dissolution equilibrium of FA-leachate interface, the formation of non-adsorptive DOM-Mn+ complex (easy to migrate), and the competitive effect of DOM on the binding sites of Mn+ on the surface of the FA matrix may play an important role in increasing the leaching level of most Mn+. By contrast, the potential of solidified FA in reducing the environmental risk level of leached Mn+ was better than that of stabilized FA. However, the immobilization capability of solidification/stabilization pretreatment on various types of Mn+ in FA should be judged according to their practical disposal environment. Compared to MLL leaching tests, Acetic Acid Buffer Solution Method (HJ/T300-2007) can effectively strengthen the exposure environment and provide a reliable reference level of environmental risk for MSWI FA disposed in MSW landfill sites.
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Affiliation(s)
- Weihua Li
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Kai Gu
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Qianwen Yu
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Yingjie Sun
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China.
| | - Yan Wang
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Mingxue Xin
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Rongxing Bian
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Huawei Wang
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Ya-Nan Wang
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
| | - Dalei Zhang
- Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao University of Technology, School of Environmental and Municipal Engineering, Qingdao 266033, China
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Tiberg C, Sjöstedt C, Karlfeldt Fedje K. Speciation of Cu and Zn in bottom ash from solid waste incineration studied by XAS, XRD, and geochemical modelling. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 119:389-398. [PMID: 33172740 DOI: 10.1016/j.wasman.2020.10.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/24/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
Millions of tons of bottom ash (BA) is generated from incineration of industrial and municipal solid waste each year within EU. The magnitude of leaching of metals like Cu and Zn is critical for hazard and risk assessment of these ashes. Although speciation of metals is a key factor to understand and predict metal leaching, speciation of Cu and Zn in BA is not well known. In this study six metal separated and carbonized BA were investigated by a combination of X-ray absorption spectroscopy, X-ray diffraction, leaching/extraction tests, and geochemical modelling. Five of the BA were from grate boilers and one from a fluidized bed incinerator. The aims were to identify similarities in Cu and Zn speciation and to identify main species. The combination of several techniques was necessary to draw conclusions about speciation and displayed coherent results. A similar speciation of Cu and Zn was indicated in the five studied grate boiler ashes although the proportions between species may vary. Copper(II) oxide and Cu metal were the main Cu species in all BA. Zinc(II) oxide and willemite (Zn2SiO4) were identified in grate boiler ashes. The fluidized bed ash contained Zn-Si-minerals and possibly franklinite or gahnite, while the Zn(II) oxide content was low, if any. The results have implications for classification and risk assessment of MIBA.
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Affiliation(s)
| | - Carin Sjöstedt
- Department of Soil and Environment, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
| | - Karin Karlfeldt Fedje
- Recovery and Management, Renova AB, Box 156, SE-401 22 Gothenburg, Sweden; Department of Architecture and Civil Engineering, Division of Water Environment Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
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Monroy Sarmiento LE, Clavier KA, Townsend TG. Trace element release from combustion ash co-disposed with municipal solid waste. CHEMOSPHERE 2020; 252:126436. [PMID: 32182511 DOI: 10.1016/j.chemosphere.2020.126436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 06/10/2023]
Abstract
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.
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Affiliation(s)
- Linda E Monroy Sarmiento
- Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL, 32611-6450, USA
| | - Kyle A Clavier
- Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL, 32611-6450, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL, 32611-6450, USA.
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Luo H, Cheng Y, He D, Yang EH. Review of leaching behavior of municipal solid waste incineration (MSWI) ash. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 668:90-103. [PMID: 30852230 DOI: 10.1016/j.scitotenv.2019.03.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
Incineration is widely adopted in modern waste management because it provides an effective way to minimize municipal solid waste that needs to be disposed of in landfills. The ash residue is often disposed by landfilling. Alternatively, the incineration ash may be recycled and reused for various applications. The crucial issues, however, are the leaching of harmful elements during the use and the end-of-life phases. This review summarizes extensive studies on leaching behavior of municipal solid waste incineration ash. Specifically, pollutants generated through leaching, factors governing leaching, methodologies to study leaching, leaching mechanisms, and treatments to reduce leaching. Many types of pollutants are generated through leaching from municipal solid waste incineration ash, in which heavy metals and organic contaminants are the most toxic and concerned. Ash properties, pH and liquid to solid ratio are the main factors governing municipal solid waste incineration ash leaching. Leaching behavior of municipal solid waste incineration ash is complicated and existing methods to evaluate leaching may not be able to represent the field conditions. Solubility and sorption are the two major leaching mechanisms. Many treatment methods have been proposed. However, not all methods are effective and some approaches are associated with high energy and high cost, which makes them less economically feasible and attractive.
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Affiliation(s)
- Hongwei Luo
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China; Energy Research Institute, Nanyang Technological University, Singapore 637553, Singapore
| | - Ying Cheng
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Dongqin He
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
| | - En-Hua Yang
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
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Li W, Sun Y, Huang Y, Shimaoka T, Wang H, Wang YN, Ma L, Zhang D. Evaluation of chemical speciation and environmental risk levels of heavy metals during varied acid corrosion conditions for raw and solidified/stabilized MSWI fly ash. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 87:407-416. [PMID: 31109541 DOI: 10.1016/j.wasman.2019.02.033] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 01/25/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
In this work, the leaching pattern, chemical speciation, and environmental risks of various heavy metals (Pb, Zn, Cu, Cd, Cr, and Ni) were investigated synchronously under different acid corrosion conditions through end-point pH leaching experiments. The heavy metals were present in raw, stabilized (phosphoric acid; chelating agent), and solidified (Portland cement) municipal solid waste incineration (MSWI) fly ash. The results showed that the stabilization and solidification pre-treatment could effectively decrease the leaching of most heavy metals. However, phosphoric acid stabilization and Portland cement solidification increased the solubility of Ni and Pb/Cu/Cd under low end-point pH conditions, while that of Cr and Pb increased under high end-point pH conditions. Overall, the leaching pattern of heavy metals was not affected by the addition of binders/additives. The results from speciation analysis showed that the bioavailable fractions (exchangeable and carbonate-bound) were leached out from initial raw or solidified/stabilized fly ash after distilled water leaching. However, with the decrease in end-point pH levels, the bioavailable fractions increased again due to the increase in acid corrosion on metal-bearing mineral matrixes. The risk assessment results indicated that, after exposing the raw or solidified/stabilized fly ash to highly acidic conditions, not only the high-content Pb/Zn/Cu, but also some low-content Cd posed potential risks to the environment. During the leaching process, under extremely acidic conditions, the increased environmental risks posed by Pb/Zn/Cu/Cd in residual fly ash solids were greatly ascribed to the increase in bioavailable fractions, which might result in the re-leaching of some heavy metals to the environment.
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Affiliation(s)
- Weihua Li
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China; Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao 266033, China
| | - Yingjie Sun
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China; Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao 266033, China.
| | - Yaomin Huang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China; Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao 266033, China
| | - Takayuki Shimaoka
- Department of Urban and Environmental Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Huawei Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China; Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao 266033, China
| | - Ya-Nan Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China; Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao 266033, China
| | - Li Ma
- Qingdao Environmental Monitoring Center Station, Qingdao 266003, China
| | - Dalei Zhang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China; Qingdao Solid Waste Pollution Control and Resource Engineering Research Center, Qingdao 266033, China
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Yin K, Chan WP, Dou X, Lisak G, Chang VWC. Vertical distribution of heavy metals in seawater column during IBA construction in land reclamation - Re-exploration of a large-scale field trial experiment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 654:356-364. [PMID: 30447575 DOI: 10.1016/j.scitotenv.2018.10.407] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/29/2018] [Accepted: 10/29/2018] [Indexed: 06/09/2023]
Abstract
Data from large-scale field trial experiments simulating the application of incineration bottom ash (IBA) for land reclamation were re-explored, to understand the spot-specific leaching characteristics and re-adsorption of heavy metals associated with various reclamation scenarios. Data showed that IBA leaching changed significantly as a function of seawater depth rather than time. The application of a chute had a minor effect on the total metal leached amounts; however, it would magnify the gradient of leaching concentrations across depths. Metal re-adsorption occurred within half an hour after IBA dumping, which however was significantly alleviated when a chute was applied. It may be ascribed to various degrees of contact with seawater of IBA, seawater movements and particle resuspension. Batch leaching tests from the laboratory under different L/S ratios were conducted as the references to "effective" leaching behaviors in the large-scale experiments, suggesting that the batch leaching test with the liquid to solid ratio = 10 provide a closer estimation of IBA leaching concentrations during land reclamation. As the current study took account of major field factors during land reclamation, including seawater depth (m), IBA loading (ton), IBA dropping method, particle dispersive area (m2), and settling time (min), these findings are valuable for the risk assessment of IBA utilization in land reclamation.
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Affiliation(s)
- Ke Yin
- Residue and Resource Reclamation Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141, Singapore; Department of Environmental Engineering, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, Jiangsu Province, China.
| | - Wei-Ping Chan
- Residue and Resource Reclamation Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141, Singapore
| | - Xiaomin Dou
- Residue and Resource Reclamation Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141, Singapore
| | - Grzegorz Lisak
- Residue and Resource Reclamation Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
| | - Victor Wei-Chung Chang
- Department of Civil Engineering, 23 College Walk, Monash University, Victoria 3800, Australia.
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Yin K, Dou X, Ren F, Chan WP, Chang VWC. Statistical comparison of leaching behavior of incineration bottom ash using seawater and deionized water: Significant findings based on several leaching methods. JOURNAL OF HAZARDOUS MATERIALS 2018; 344:635-648. [PMID: 29112922 DOI: 10.1016/j.jhazmat.2017.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/10/2017] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
Bottom ashes generated from municipal solid waste incineration have gained increasing popularity as alternative construction materials, however, they contains elevated heavy metals posing a challenge for its free usage. Different leaching methods are developed to quantify leaching potential of incineration bottom ashes meanwhile guide its environmentally friendly application. Yet, there are diverse IBA applications while the in situ environment is always complicated, challenging its legislation. In this study, leaching tests were conveyed using batch and column leaching methods with seawater as opposed to deionized water, to unveil the metal leaching potential of IBA subjected to salty environment, which is commonly encountered when using IBA in land reclamation yet not well understood. Statistical analysis for different leaching methods suggested disparate performance between seawater and deionized water primarily ascribed to ionic strength. Impacts of leachant are metal-specific dependent on leaching methods and have a function of intrinsic characteristics of incineration bottom ashes. Leaching performances were further compared on additional perspectives, e.g. leaching approach and liquid to solid ratio, indicating sophisticated leaching potentials dominated by combined geochemistry. It is necessary to develop application-oriented leaching methods with corresponding leaching criteria to preclude discriminations between different applications, e.g., terrestrial applications vs. land reclamation.
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Affiliation(s)
- Ke Yin
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore
| | - Xiaomin Dou
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore
| | - Fei Ren
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore
| | - Wei-Ping Chan
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore.
| | - Victor Wei-Chung Chang
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore; Department of Civil Engineering, 23 College Walk, Monash University, Victoria 3800, Australia
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11
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Ilyas A, Muthanna TM. Metal removal efficiency, operational life and secondary environmental impacts of a stormwater filter developed from iron-oxide-amended bottom ash. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2017; 52:1330-1340. [PMID: 28961058 DOI: 10.1080/10934529.2017.1362291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The aim of this paper was to conduct pilot-scale column tests on an alternative treatment filter designed for the treatment of highway stormwater in cold climates. The study evaluated adsorption performance of the filter with regard to the four most commonly found metals (Cu, Ni, Pb, and Zn) in highway stormwater. An alternative method was used to estimate the operational life of the filter from the adsorption test data without a breakthrough under high hydraulic loads. The potential environmental impact of the filter was assessed by comparing desorption test data with four different environmental quality standards. The proposed filter achieved high adsorption (over 90%) of the target metals. The comparisons of desorption and leaching data with the environmental standards indicated that iron-oxide/bottom ash was non-hazardous, reusable and without serious environmental risks. The operational life and filter dimensions were highly dependent on rainfall depth, which indicated that the filter design would have to be adapted to suit the climate. To fully appreciate the performance and environmental aspects, the filter unit should be tested in the field and the testing should explicitly include ecotoxicological and life cycle impacts.
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Affiliation(s)
- Aamir Ilyas
- a Department of Civil and Environmental Engineering , Norwegian University of Science and Technology , Trondheim , Norway
| | - Tone M Muthanna
- a Department of Civil and Environmental Engineering , Norwegian University of Science and Technology , Trondheim , Norway
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12
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Pecorini I, Baldi F, Bacchi D, Carnevale EA, Corti A. Leaching behaviour of hazardous waste under the impact of different ambient conditions. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 63:96-106. [PMID: 27810123 DOI: 10.1016/j.wasman.2016.10.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 09/23/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
The overall objective of this study is to provide an improved basis for the assessment of the leaching behaviour of waste marked as hazardous partly stabilised (European waste catalogue code 19 03 04∗). Four samples of hazardous partly stabilised waste were subjected to two leaching tests: up-flow column tests and batch equilibrium tests. The research was carried out in two directions: the first aims at comparing the results of the two experimental setups while the second aims at assessing the impact of different ambient conditions on the leaching behaviour of waste. Concerning this latter objective the effect of mesophilic temperature, mechanical constraints and acid environment were tested through column percolation tests. Results showed no significant differences between batch and column leaching test outcomes when comparing average concentrations calculated at a liquid to solid ratio of 10:1 l kg-1 TS. Among the tested ambient conditions, the presence of an acid environment (pH=4.5) accelerated the leaching process resulting in a higher cumulative released quantity measured on the majority of the investigated polluting substances. On the contrary, the effect of temperature and mechanical constraints seemed to not affect the process showing final contents even lower than values found for the standard test. This result was furthermore confirmed by the application of the principal component analysis.
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Affiliation(s)
- Isabella Pecorini
- DIEF, Department of Industrial Engineering, University of Florence, Via Santa Marta 3, 50139 Florence, Italy.
| | - Francesco Baldi
- DIEF, Department of Industrial Engineering, University of Florence, Via Santa Marta 3, 50139 Florence, Italy
| | - Donata Bacchi
- DIEF, Department of Industrial Engineering, University of Florence, Via Santa Marta 3, 50139 Florence, Italy
| | - Ennio Antonio Carnevale
- DIEF, Department of Industrial Engineering, University of Florence, Via Santa Marta 3, 50139 Florence, Italy
| | - Andrea Corti
- DIISM, Department of Information Engineering and Mathematic, University of Siena, Via Roma 56, 56100 Siena, Italy
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13
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Stiernström S, Wik O, Bendz D. Evaluation of frameworks for ecotoxicological hazard classification of waste. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 58:14-24. [PMID: 27639283 DOI: 10.1016/j.wasman.2016.08.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 06/06/2023]
Abstract
A new harmonized EU regulation for the classification of waste came into effect on 1st June 2015, in which the criteria and assessment methods for the classification of hazardous waste are harmonized with other internationally agreed-upon systems for hazard classification of chemicals (CLP). However, criteria and guidance for the assessment of ecotoxicological hazard (Hazard Property 14, HP14) are still lacking for waste classification. This paper have evaluated and compared two HP14 classification frameworks: (i) a calculation method (summation) for mixtures, and (ii) leaching tests. The two frameworks were evaluated by surveying and evaluating ecotoxicological data for Cu, Zn, K and Ca species in bottom ash from incinerated waste, together with geochemical speciation modelling. Classification based on the summation method proved to be highly sensitive to the choice of speciation and ecotoxicological classification. This results in a wide range of critical concentrations triggering hazardous classification (in particular for Cu and Zn). Important parameters governing the availability of toxic elements, such as transformation from one species to another and complexation on organic or inorganic sorbents, are not accounted for. Geochemical modelling revealed that a testing strategy built on CLP based leaching tests (liquid/solid ratio (L/S)⩾10,000, pH range 5.5-8.5) avoids bias and is superior to the summation method with respect to both precision and accuracy. A testing strategy built on leaching tests, designed for risk assessment purposes, (L/S ratio of 10, natural pH of the ash) severely underestimate the hazard associated with the presence of toxic compounds (Cu and Zn), while simultaneously falsely indicate a hazardousness due to the presence of non-toxic compounds (Ca and K). However, the testing methods adopted by CLP are problematic from a practical and functional point of view. To conclude, the L/S ratio and pH were found to be critical for hazard classification based on leaching test methods. Further studies are needed to develop a relevant, practical and functional testing strategy for HP14 hazardous waste classification.
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Affiliation(s)
- S Stiernström
- Ragn-Sells, Väderholmes gård, SE-191 36 Sollentuna, Sweden.
| | - O Wik
- Swedish Geotechnical Institute, Olaus Magnus väg, 35, SE-581 93 Linköping, Sweden
| | - D Bendz
- Swedish Geotechnical Institute, Olaus Magnus väg, 35, SE-581 93 Linköping, Sweden
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14
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Gupta N, Yadav KK, Kumar V. A review on current status of municipal solid waste management in India. J Environ Sci (China) 2015; 37:206-17. [PMID: 26574106 DOI: 10.1016/j.jes.2015.01.034] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/30/2014] [Accepted: 01/27/2015] [Indexed: 05/21/2023]
Abstract
Municipal solid waste management is a major environmental issue in India. Due to rapid increase in urbanization, industrialization and population, the generation rate of municipal solid waste in Indian cities and towns is also increased. Mismanagement of municipal solid waste can cause adverse environmental impacts, public health risk and other socio-economic problem. This paper presents an overview of current status of solid waste management in India which can help the competent authorities responsible for municipal solid waste management and researchers to prepare more efficient plans.
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Affiliation(s)
- Neha Gupta
- Institute of Environment and Development Studies, Bundelkhand University, Jhansi 284128, India.
| | - Krishna Kumar Yadav
- Institute of Environment and Development Studies, Bundelkhand University, Jhansi 284128, India
| | - Vinit Kumar
- Institute of Environment and Development Studies, Bundelkhand University, Jhansi 284128, India
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15
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Del Valle-Zermeño R, Chimenos JM, Giró-Paloma J, Formosa J. Use of weathered and fresh bottom ash mix layers as a subbase in road constructions: environmental behavior enhancement by means of a retaining barrier. CHEMOSPHERE 2014; 117:402-409. [PMID: 25180484 DOI: 10.1016/j.chemosphere.2014.07.095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 07/28/2014] [Accepted: 07/30/2014] [Indexed: 06/03/2023]
Abstract
The presence of neoformed cement-like phases during the weathering of non-stabilized freshly quenched bottom ash favors the development of a bound pavement material with improved mechanical properties. Use of weathered and freshly quenched bottom ash mix layers placed one over the other allowed the retention of leached heavy metals and metalloids by means of a reactive percolation barrier. The addition of 50% of weathered bottom ash to the total subbase content diminished the release of toxic species to below environmental regulatory limits. The mechanisms of retention and the different processes and factors responsible of leaching strongly depended on the contaminant under concern as well as on the chemical and physical factors. Thus, the immediate reuse of freshly quenched bottom ash as a subbase material in road constructions is possible, as both the mechanical properties and long-term leachability are enhanced.
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Affiliation(s)
- R Del Valle-Zermeño
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Universitat de Barcelona (UB), Martí i Franqués, 1, 08028 Barcelona, Spain
| | - J M Chimenos
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Universitat de Barcelona (UB), Martí i Franqués, 1, 08028 Barcelona, Spain.
| | - J Giró-Paloma
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Universitat de Barcelona (UB), Martí i Franqués, 1, 08028 Barcelona, Spain
| | - J Formosa
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Universitat de Barcelona (UB), Martí i Franqués, 1, 08028 Barcelona, Spain; Departament Construccions Arquitectòniques II, Universitat Politècnica de Catalunya (UPC), Av. Dr. Marañón 44, 08028 Barcelona, Spain
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16
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del Valle-Zermeño R, Formosa J, Prieto M, Nadal R, Niubó M, Chimenos JM. Pilot-scale road subbase made with granular material formulated with MSWI bottom ash and stabilized APC fly ash: environmental impact assessment. JOURNAL OF HAZARDOUS MATERIALS 2014; 266:132-140. [PMID: 24394668 DOI: 10.1016/j.jhazmat.2013.12.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/29/2013] [Accepted: 12/12/2013] [Indexed: 06/03/2023]
Abstract
A granular material (GM) to be used as road sub-base was formulated using 80% of weathered bottom ash (WBA) and 20% of mortar. The mortar was prepared separately and consisted in 50% APC and 50% of Portland cement. A pilot-scale study was carried on by constructing three roads in order to environmentally evaluate the performance of GM in a real scenario. By comparing the field results with those of the column experiments, the overestimations observed at laboratory scale can be explained by the potential mechanisms in which water enters into the road body and the pH of the media. An exception was observed in the case of Cu, whose concentration release at the test road was higher. The long-time of exposure at atmospheric conditions might have favoured oxidation of organic matter and therefore the leaching of this element. The results obtained showed that immobilization of all heavy metals and metalloids from APC is achieved by the pozzolanic effect of the cement mortar. This is, to the knowledge of the authors, the only pilot scale study that is considering reutilization of APC as a safe way to disposal.
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Affiliation(s)
- R del Valle-Zermeño
- Department of Materials Science and Metallurgical Engineering, University of Barcelona (UB), Martí i Franquès, 1, E-08028 Barcelona, Spain
| | - J Formosa
- Department of Architectural Technology II, Polytechnic University of Catalonia (UPC), Ave. Dr. Marañón 44, E-08028 Barcelona, Spain
| | - M Prieto
- Valorización de Escorias para la Construcción S.A. (VECSA), Tarragona, Spain
| | - R Nadal
- Servei d'Incineració de Residus Urbans S.A. (SIRUSA), Tarragona, Spain
| | - M Niubó
- Department of Materials Science and Metallurgical Engineering, University of Barcelona (UB), Martí i Franquès, 1, E-08028 Barcelona, Spain
| | - J M Chimenos
- Department of Materials Science and Metallurgical Engineering, University of Barcelona (UB), Martí i Franquès, 1, E-08028 Barcelona, Spain.
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17
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Stiernström S, Enell A, Wik O, Borg H, Breitholtz M. An ecotoxicological evaluation of aged bottom ash for use in constructions. WASTE MANAGEMENT (NEW YORK, N.Y.) 2014; 34:86-92. [PMID: 24188924 DOI: 10.1016/j.wasman.2013.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 09/13/2013] [Accepted: 10/03/2013] [Indexed: 06/02/2023]
Abstract
Municipal and Industrial Solid Waste Incineration (MISWI) bottom ash is mainly deposited in landfills, but natural resources and energy could be saved if these ash materials would be used in geotechnical constructions. To enable such usage, knowledge is needed on their potential environmental impact. The aim of this study was to evaluate the ecotoxicity of leachates from MISWI bottom ash, aged for five years, in an environmental relevant way using a sequential batch leaching method at the Liquid/Solid-ratio interval 1-3, and to test the leachates in a (sub)chronic ecotoxicity test. Also, the leachates were characterized chemically and with the technique of diffusive gradients in thin films (DGTs). By comparing established ecotoxicity data for each element with chemically analysed and labile concentrations in the leachates, potentially problematic elements were identified by calculating Hazard Quotients (HQ). Overall, our results show that the ecotoxicity was in general low and decreased with increased leaching. A strong correspondence between calculated HQs and observed toxicity over the full L/S range was observed for K. However, K will likely not be problematic from a long-term environmental perspective when using the ash, since it is a naturally occurring essential macro element which is not classified as ecotoxic in the chemical legislation. Although Cu was measured in total concentrations close to where a toxic response is expected, even at L/S 3, the DGT-analysis showed that less than 50% was present in a labile fraction, indicating that Cu is complexed by organic ligands which reduce its bioavailability.
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Affiliation(s)
- S Stiernström
- Department of Applied Environmental Science (ITM), Stockholm University, Stockholm SE-106 91, Sweden.
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18
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Su L, Guo G, Shi X, Zuo M, Niu D, Zhao A, Zhao Y. Copper leaching of MSWI bottom ash co-disposed with refuse: effect of short-term accelerated weathering. WASTE MANAGEMENT (NEW YORK, N.Y.) 2013; 33:1411-1417. [PMID: 23490365 DOI: 10.1016/j.wasman.2013.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 01/18/2013] [Accepted: 02/08/2013] [Indexed: 06/01/2023]
Abstract
Co-disposal of refuse with municipal solid waste incinerator (MSWI) bottom ash (IBA) either multi-layered as landfill cover or mixed with refuse could pose additional risk to the environment because of enhanced leaching of heavy metals, especially Cu. This study applied short-term accelerated weathering to IBA, and monitored the mineralogical and chemical properties of IBA during the weathering process. Cu extractability of the weathered IBA was then evaluated using standard leaching protocols (i.e. SPLP and TCLP) and co-disposal leaching procedure. The results showed that weathering had little or no beneficial effect on Cu leaching in SPLP and TCLP, which can be explained by the adsorption and complexation of Cu with DOM. However, the Cu leaching of weathered IBA was reduced significantly when situated in fresh simulated landfill leachate. This was attributed to weakening Cu complexation with fulvic acid or hydrophilic fractions and/or intensifying Cu absorption to neoformed hydr(oxide) minerals in weathered IBA. The amount of total leaching Cu and Cu in free or labile complex fraction (the fraction with the highest mobility and bio-toxicity) of the 408-h weathered IBA were remarkably decreased by 86.3% and 97.6% in the 15-day co-disposal leaching test. Accelerated weathering of IBA may be an effective pretreatment method to decrease Cu leaching prior to its co-disposal with refuse.
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Affiliation(s)
- Lianghu Su
- The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
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19
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Biganzoli L, Ilyas A, Praagh MV, Persson KM, Grosso M. Aluminium recovery vs. hydrogen production as resource recovery options for fine MSWI bottom ash fraction. WASTE MANAGEMENT (NEW YORK, N.Y.) 2013; 33:1174-1181. [PMID: 23453355 DOI: 10.1016/j.wasman.2013.01.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 09/26/2012] [Accepted: 01/31/2013] [Indexed: 06/01/2023]
Abstract
Waste incineration bottom ash fine fraction contains a significant amount of aluminium, but previous works have shown that current recovery options based on standard on-step Eddy Current Separation (ECS) have limited efficiency. In this paper, we evaluated the improvement in the efficiency of ECS by using an additional step of crushing and sieving. The efficiency of metallic Al recovery was quantified by measuring hydrogen gas production. The ash samples were also tested for total aluminium content with X-ray fluorescence spectroscopy (XRF). As an alternative to material recovery, we also investigated the possibility to convert residual metallic Al into useful energy, promoting H2 gas production by reacting metallic Al with water at high pH. The results show that the total aluminium concentration in the <4 mm bottom ash fraction is on average 8% of the weight of the dry ash, with less than 15% of it being present in the metallic form. Of this latter, only 21% can be potentially recovered with ECS combined with crushing and sieving stages and subsequently recycled. For hydrogen production, using 10MNaOH at 1L/S ratio results in the release of 6-11l of H2 gas for each kilogram of fine dry ash, equivalent to an energy potential of 118 kJ.
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Affiliation(s)
- Laura Biganzoli
- D.I.I.A.R. Environmental Section, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
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Lin YC, Panchangam SC, Wu CH, Hong PKA, Lin CF. Effects of water washing on removing organic residues in bottom ashes of municipal solid waste incinerators. CHEMOSPHERE 2011; 82:502-506. [PMID: 21112610 DOI: 10.1016/j.chemosphere.2010.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Revised: 11/02/2010] [Accepted: 11/03/2010] [Indexed: 05/30/2023]
Abstract
Due to their potential toxicity and odourous nature, the residual organics in municipal solid waste incinerators are recently gaining attention as an important issue of resources recovery apart from their complex mixture of organic counterpart. Studies of the organic fractions in municipal solid waste incinerator residues have been limited. In this study, extended solid-phase extraction of the water-washed bottom ash and liquid-phase extraction of the washing water were carried out with regard to bottom ash samples from three mass-burning incinerators in Taipei County (Taiwan) during four consecutive seasons of year 2008-2009. Supercritical fluid extraction and Soxtec extraction techniques along with GC-MS were successfully used to characterize the residual organics in weathered and washed bottom ashes. Supercritical fluid extraction provided the quantification of aliphatics and aromatic compounds such as hexanoic acid and benzaldehyde, respectively. Soxtec extraction was useful for qualitative analysis of aromatic and aliphatic groups in the ashes and many of which were odourous and toxic compounds. By mixing one unit weight (g) bottom ash with two unit volume (mL) water for 15 min, total organic carbon in the bottom ash was greatly reduced (e.g., from 4.1 to 1.8 wt.%). Among the removed were foul odour-causing compounds such as pyridine and quinoline derivatives, while some aromatic compounds such as 4-hydroxybenzaldehyde and low-molecular-weight aliphatics such as hexanoic acid remained. The results here suggest that washing with water can be an effective pre-treatment step for removing odour-causing and environmental concerned organics.
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Affiliation(s)
- Yen-Ching Lin
- Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan, ROC
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21
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Sivula L, Ilander A, Väisänen A, Rintala J. Weathering of gasification and grate bottom ash in anaerobic conditions. JOURNAL OF HAZARDOUS MATERIALS 2010; 174:344-351. [PMID: 19818557 DOI: 10.1016/j.jhazmat.2009.09.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 08/28/2009] [Accepted: 09/11/2009] [Indexed: 05/28/2023]
Abstract
The effect of anaerobic conditions on weathering of gasification and grate bottom ash were studied in laboratory lysimeters. The two parallel lysimeters containing the same ash were run in anaerobic conditions for 322 days, after which one was aerated for 132 days. The lysimeters were watered throughout the study and the quality of leachates and changes in the binding of elements into ash were observed. The results show that organic carbon content and initial moisture of ashes are the key parameters affecting the weathering of ashes. In the grate ash the biodegradation of organic carbon produced enough CO(2) to regulate pH. In contrast the dry gasification ash, containing little organic carbon, was not carbonated under anaerobic conditions and the pH decreased only after aeration was started. During the aeration the CO(2) absorption capacity was not reached, indicating that intense aeration would be needed to fully carbonate gasification ash. The results indicate that in common weathering practice the main emissions-reducing processes are leaching and carbonation due to CO(2) from biodegradation. The results of the aeration study suggest that the role of atmospheric CO(2) in the weathering process was insignificant.
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Affiliation(s)
- Leena Sivula
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, FI-40014 University of Jyväskylä, Finland.
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