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Weiksnar KD, Marks EJ, Deaderick MJ, Meija-Ruiz I, Ferraro CC, Townsend TG. Impacts of advanced metals recovery on municipal solid waste incineration bottom ash: aggregate characteristics and performance in portland limestone cement concrete. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 187:70-78. [PMID: 38996621 DOI: 10.1016/j.wasman.2024.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 06/06/2024] [Accepted: 07/05/2024] [Indexed: 07/14/2024]
Abstract
The optimization of alternative materials in concrete production continues to garner considerable attention in order to meet sustainability goals and supplement natural materials. Portland limestone cement (PLC) and municipal solid waste incineration (MSWI) bottom ash (BA) have been proposed separately as green cement and coarse aggregate supplement in low-strength concrete production, creating sustainable products and alternative disposal scenario for a waste material. This study discusses the impact of advanced ash processing techniques on aggregates and presents the performance of concrete incorporating both of these products with PLC for the first time. Two sources of MSWI BA were investigated, one as-produced (TMR) and one processed with novel advanced metals recovery (AMR). The AMR process reduced total Al content in ash compared to TMR (20,500 vs 17,000 mg/kg), though not aluminum oxide content, as the AMR process targets metallic aluminum. A composition study on both aggregates supports a reduction in ferrous and non-ferrous metals following the AMR process. All control and test mixes met 28-day compressive strength requirements (17 Mpa). Both AMR and TMR MSWI BA-amended concretes yielded compressive strengths below control specimens (no ash) ranging from 17 to 23 MPa, with little to no difference observed dependent on MSWI BA processing. The life-cycle discussion supports benefits deriving from supplementing naturally mined materials and recovering ferrous and nonferrous metals with the AMR process.
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Affiliation(s)
- Kate D Weiksnar
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Ethan J Marks
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Margaret J Deaderick
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Isabella Meija-Ruiz
- Department of Materials Sciences and Engineering, University of Florida, P.O. Box 116400, Gainesville, FL 32611-6450, USA
| | - Christopher C Ferraro
- Department of Civil and Coastal Engineering, University of Florida, P.O. Box 116580, Gainesville, FL 32611-6450, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA.
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Clavier M, Ndiaye K, Aggoun S, Bodet R, Delaporte B. Investigation on the leaching behavior of natural aggregates using percolation test and total content. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:43339-43350. [PMID: 38902443 DOI: 10.1007/s11356-024-33972-w] [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: 09/29/2023] [Accepted: 06/08/2024] [Indexed: 06/22/2024]
Abstract
In the construction industry, environmental behavior of aggregates has been monitored thanks to leaching tests, especially for alternative aggregates obtained from waste (e.g., construction and demolition waste, MSWI). Few studies were carried on the leaching behavior of natural aggregates, which are often not regulated for their substance release in most EU member states (as France). Leachable content of some heavy metals, halides, and sulfates on natural aggregates was investigated using up-flow percolation test EN 16637-3 and compared to threshold values. Only three samples (NS2, NG1, and NG8) show one element which exceeded threshold values (As, Zn, As, respectively), among the 19 natural aggregates tested for leaching. In this study, three natural aggregates (NG1, NS1, NS2) have been chosen because of their measurable leaching values. Total content was obtained through acid digestion. Influence of grain size on leaching results was investigated. Predominant release mechanisms were determined using EN 16637-3 - Annex D, based on percolation results such as pH, electrical conductivity, and leached content, and were then discussed. Detailed results for releases of As, Ba, Ni, Zn, SO42-, and F- were investigated. EN 16637-3 - Annex D shows some limits, especially for trace elements. The pH was found to be one of the most important factors influencing leaching release of most elements, being more important than grain size. By comparing total content with released quantities, it has been shown that As and Mo in NS2 are easily leached, hence present in a very soluble chemical form. Determining release mechanisms accurately in this study seems only possible for elements present in significant amounts.
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Affiliation(s)
| | - Khadim Ndiaye
- CY Cergy Paris Université, L2MGC, F-95000, Cergy, France
| | - Salima Aggoun
- CY Cergy Paris Université, L2MGC, F-95000, Cergy, France
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Akfas F, Elghali A, Toubri Y, Samrane K, Munoz M, Bodinier JL, Benzaazoua M. Environmental assessment of phosphogypsum: A comprehensive geochemical modeling and leaching behavior study. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 359:120929. [PMID: 38669878 DOI: 10.1016/j.jenvman.2024.120929] [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: 02/16/2024] [Revised: 03/26/2024] [Accepted: 04/14/2024] [Indexed: 04/28/2024]
Abstract
Understanding the variations in the geochemical composition of phosphogypsum (PG) destined for storage or valorization is crucial for assessing the safety and operational efficacy of waste management. The present study aimed to investigate the environmental behavior of PG using different leaching tests and to evaluate its geochemical behavior using geochemical modeling. Regarding the chemical characterization, the PG samples were predominantly composed of Ca (23.03-23.35 wt%), S (17.65-17.71 wt%), and Si (0.75-0.82 wt%). Mineralogically, the PG samples were primarily composed of gypsum (94.2-95.9 wt%) and quartz (1.67-1.76 wt%). Moreover, the automated mineralogy revealed the presence of apatite, fluorine and malladrite phases. The overall findings of the leaching tests showed that PG could be considered as non-hazardous material according to US Environmental Protection Agency limitations. However, a high leachability of elements at a L/S of 2 under acidic conditions ([Ca] = 166.52-199.87 mg/L, [S] = 207.9-233.59 mg/L, [F] = 248.62-286.65 mg/L) is observed. The weathering cell test revealed a considerable cumulative concentration over 90 days indicating potential adverse effects on the nearby environment (S: 8000 mg/kg, F: 3000 mg/kg, P: 700 mg/kg). Based on these results, it could be estimated that the surface storage of PG could have a serious impact on the environment. In this context, a simulation model was developed based on weathering cell results showed encouraging results for treating PG leachate using CaO before its disposal. Additionally, PHREEQC was used to analyze the speciation of major elements and calculate mineral phase saturation indices in PG leaching solutions. The findings revealed pH-dependent speciation for Ca, S, P, and F. The study identified gypsum, anhydrite, and bassanite as the key phases governing the dissolution of these elements.
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Affiliation(s)
- Fatima Akfas
- Geology & Sustainable Mining Institute, Mohammed VI Polytechnic University, Lot-660, Benguerir 43150, Morocco
| | - Abdellatif Elghali
- Geology & Sustainable Mining Institute, Mohammed VI Polytechnic University, Lot-660, Benguerir 43150, Morocco.
| | - Youssef Toubri
- Geology & Sustainable Mining Institute, Mohammed VI Polytechnic University, Lot-660, Benguerir 43150, Morocco
| | - Kamal Samrane
- Sustainability & Green Industrial Development, OCP Group S.A, Morocco
| | - Manuel Munoz
- Geoscience Montpellier, University of Montpellier, Montpellier- Cedex 5- 34095, France
| | - Jean-Louis Bodinier
- Geology & Sustainable Mining Institute, Mohammed VI Polytechnic University, Lot-660, Benguerir 43150, Morocco; Geoscience Montpellier, University of Montpellier, Montpellier- Cedex 5- 34095, France
| | - Mostafa Benzaazoua
- Geology & Sustainable Mining Institute, Mohammed VI Polytechnic University, Lot-660, Benguerir 43150, Morocco
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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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Lehmusto J, Tesfaye F, Karlström O, Hupa L. Ashes from challenging fuels in the circular economy. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 177:211-231. [PMID: 38342059 DOI: 10.1016/j.wasman.2024.01.051] [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: 02/16/2023] [Revised: 01/21/2024] [Accepted: 01/30/2024] [Indexed: 02/13/2024]
Abstract
In line with the objectives of the circular economy, the conversion of waste streams to useful and valuable side streams is a central goal. Ash represents one of the main industrial side-products, and using ashes in other than the present landfilling applications is, therefore, a high priority. This paper reviews the properties and utilization of ashes of different biomass power plants and waste incinerations, with a focus on the past decade. Possibilities for ash utilization are of uttermost importance in terms of circular economy and disposal of landfills. However, considering its applicability, ash originating from the heat treatment of chemically complex fuels, such as biomass and waste poses several challenges such as high heavy metal content and the presence of toxic and/or corrosive species. Furthermore, the physical properties of the ash might limit its usability. Nevertheless, numerous studies addressing the utilization possibilities of challenging ash in various applications have been carried out over the past decade. This review, with over 300 references, surveys the field of research, focusing on the utilization of biomass and municipal solid waste (MSW) ashes. Also, metal and phosphorus recovery from different ashes is addressed. It can be concluded that the key beneficial properties of the ash types addressed in this review are based on their i) alkaline nature suitable for neutralization reactions, ii) high adsorption capabilities to be used in CO2 capture and waste treatment, and iii) large surface area and appropriate chemical composition for the catalyst industry. Especially, ashes rich in Al2O3 and SiO2 have proven to be promising alternative catalysts in various industrial processes and as precursors for synthetic zeolites.
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Affiliation(s)
- Juho Lehmusto
- Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Henrikinkatu 2, FI-20500 Turku, Finland.
| | - Fiseha Tesfaye
- Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Henrikinkatu 2, FI-20500 Turku, Finland
| | - Oskar Karlström
- Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Henrikinkatu 2, FI-20500 Turku, Finland; Industrial Engineering and Management, University of Turku, Vesilinnantie 5, 20500 FI-20500 Turku, Finland
| | - Leena Hupa
- Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Henrikinkatu 2, FI-20500 Turku, Finland
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Spreadbury CJ, Magnuson JK, Clavier KA, Laux SJ, Townsend TG. Effect of waste-derived soil amendments on mitigating leaching impacts from municipal solid waste incineration (MSWI) ash. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 169:186-195. [PMID: 37453306 DOI: 10.1016/j.wasman.2023.07.007] [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: 01/17/2023] [Revised: 06/15/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
This study explores modifying a sandy soil with a low solid to liquid partitioning coefficient (Kd) by adding amendments including iron-rich industrial slag byproducts and biochars, which contain sorption sites for trace metals present in MSWI ash leachate (notably Sb, cited as a concern for reuse applications). Kd values for Sb were determined for the sandy soil to be as low as 1.6 ± 0.1 L/kg. With amendments, Kd values varied from 1.4 ± 0.2 L/kg for combined ash leachate exposed to a blend of sandy soil and 20% iron slag, to 990 L/kg for combined ash leachate exposed to a blend of sandy soil and 20% magnetic solids. A blend of 20% magnetic solids showed orders of magnitude increase beyond 100% sandy soil. The biochars showed limited capacity to reduce leached Sb in the ash-derived leachate, which is likely due to negative surface charges of the biochars and Sb at basic pH. A risk assessment (US EPA IWEM) performed using experimental Kd for each blend suggests that using soil amendments could reduce leached concentrations at points of concern, which could open additional avenues for ash reuse.
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Affiliation(s)
- Chad J Spreadbury
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Jordan K Magnuson
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Kyle A Clavier
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Steven J Laux
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA.
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Spreadbury CJ, Weiksnar KD, Laux S, Townsend TG. Distributions of trace elements within MSWI bottom and combined ash components: Implications for reuse practices. CHEMOSPHERE 2023; 336:139198. [PMID: 37315860 DOI: 10.1016/j.chemosphere.2023.139198] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 05/15/2023] [Accepted: 06/11/2023] [Indexed: 06/16/2023]
Abstract
Concentrations of 25 inorganic elements were measured in both bulk ash and individual ash components from residuals at three municipal solid waste incineration (MSWI) facilities in the US (two combined ash (CA) and one bottom ash (BA)). Concentrations were assessed based on particle size and component to understand the contribution from each fraction. The results found that among facilities, the finer size fractions contained elevated concentrations of trace elements of concern (As, Pb, Sb) when compared to the coarse fraction, but concentrations varied among facilities depending on the type of ash and differences in advanced metals recovery processes. This study focused on several constituents of potential concern, As, Ba, Cu, Pb, and Sb, and found that the main components of MSWI ash (glass, ceramic, concrete, and slag) are sources of these elements in the ash streams. For many elements, concentrations were significantly higher in CA bulk and component fractions opposed to BA streams. An acid treatment procedure and scanning electron microscopy/energy-dispersive x-ray spectroscopy analysis revealed that some elements, such as As in concrete, are result of the inherent properties of the component, but other elements, such as Sb, form on the surface during or after incineration and can be removed. Some Pb and Cu concentrations were attributed to inclusions in the glass or slag introduced into the material during the incineration process. Understanding the contributions of each ash component provides critical information for developing strategies to reduce trace element concentrations in ash streams to promote reuse opportunities.
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Affiliation(s)
- Chad J Spreadbury
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL, 32611-6450, USA
| | - Kate D Weiksnar
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL, 32611-6450, USA
| | - Steve Laux
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL, 32611-6450, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL, 32611-6450, USA.
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Weiksnar KD, Clavier KA, Robey NM, Townsend TG. Changes in trace metal concentrations throughout the phosphogypsum lifecycle. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158163. [PMID: 35988635 DOI: 10.1016/j.scitotenv.2022.158163] [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: 06/10/2022] [Revised: 08/08/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Phosphogypsum (PG) samples from four distinct sources in the Southeastern US were analyzed to explore the variation in total metal content between newly generated (fresh) PG and PG disposed of in phosphogypsum stacks for different lengths of time (stack). Fresh PG exhibited greater total metal concentrations relative to stack PG, including those identified in the literature as important from a risk assessment perspective (As, Cd, Co, Cr, Cu, Pb, and Zn). The pH varied between fresh and stack PG, with some stack samples exhibiting lower pH than fresh samples, however the relationship between pH and age of sample was not linear. Stack samples with pH values similar to fresh samples possessed lower concentrations of total inorganic metals than fresh samples suggesting that process water drainage and stack location play an important role in the reusability of PG as they can affect the pH of stack PG and total inorganic metal concentrations. Overall observations show that stacking PG for three or more years prior to beneficial reuse provides a construction material with lower total metal concentrations than fresh PG.
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Affiliation(s)
- Kate D Weiksnar
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Kyle A Clavier
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Nicole M Robey
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA.
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Tian Y, Themelis NJ, Zhao D, Thanos Bourtsalas AC, Kawashima S. Stabilization of Waste-to-Energy (WTE) fly ash for disposal in landfills or use as cement substitute. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 150:227-243. [PMID: 35863171 DOI: 10.1016/j.wasman.2022.06.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 06/23/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
This study investigated two approaches for managing Waste-to-Energy (WTE) fly ash (FA): (i) phosphoric acid stabilization of FA and disposal in non-hazardous landfills, so that it can pass the U.S. TCLP procedure and meet the U.S. Resource Conservation and Recovery Act (RCRA) standards; (ii) use of FA or phosphoric acid stabilized fly ash (PFA) as cement substitute in construction for avoiding disposal in landfills and reducing the consumption of Portland cement. The effect of stabilization was identified by TCLP tests and XRD quantification (QXRD), which showed that the economically optimal concentration for PFA to pass the RCRA was 1 mol/L H3PO4 (equivalent to 0.4 mol of H3PO4/kg of FA). Zn/Pb-phosphates were formed in treated ash by using high concentration H3PO4 (e.g., 3 mol/L). Thus, the hazardous FA was chemically stabilized to PFA, that were both discussed as cement substitute. QXRD and SEM results showed that both FA and PFA (1 mol/L H3PO4) chemically reacted with cement and water. Up to 25 vol% of the cement can be replaced by FA or PFA, with similar mechanical performance of cement mortars than that of reference. Testing by LEAF Method 1313-pH dependence showed that the FA and PFA cement mortars exhibited the same leachability of heavy metals; therefore, this study demonstrated the technical feasibility of utilizing either raw FA or stabilized PFA as supplementary cementitious material. The leachability of heavy metals in optimal FA or PFA 25 vol% cement mortar was under the U.K. WAC non-hazardous limits.
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Affiliation(s)
- Yixi Tian
- Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA.
| | - Nickolas J Themelis
- Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA
| | - Diandian Zhao
- Department of Civil Engineering and Engineering Mechanics, Columbia University, New York, NY 10027, USA
| | - A C Thanos Bourtsalas
- Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA
| | - Shiho Kawashima
- Department of Civil Engineering and Engineering Mechanics, Columbia University, New York, NY 10027, USA
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Azadgoleh MA, Mohammadi MM, Ghodrati A, Sharifi SS, Palizban SMM, Ahmadi A, Vahidi E, Ayar P. Characterization of contaminant leaching from asphalt pavements: A critical review of measurement methods, reclaimed asphalt pavement, porous asphalt, and waste-modified asphalt mixtures. WATER RESEARCH 2022; 219:118584. [PMID: 35580389 DOI: 10.1016/j.watres.2022.118584] [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: 12/06/2021] [Revised: 04/29/2022] [Accepted: 05/08/2022] [Indexed: 06/15/2023]
Abstract
In recent years, the pavement industry has been seeking sustainable development through recycling reclaimed asphalt pavement and reusing other waste materials as replacements for asphalt mixture constituents. Incorporating waste material into asphalt mixture and the presence of pollutants such as exhaust fumes and gasoline due to vehicle traffic may lead to contaminants leaching from asphalt pavements to underlying soil layers and groundwater aquifers, posing serious risks to ecosystems and the environment. To cast light on contaminant leaching from asphalt pavements, this article presents a comprehensive review of the literature that is divided into four research areas: evaluation of leaching measurement methods, leaching from recycled asphalt materials, leaching characteristics of porous asphalt pavements, and waste-modified asphalt mixtures. Moreover, a critical discussion of bibliometric data, literature content and knowledge gaps in this domain is provided to help highway agencies and environmental scientists address contaminant leaching from asphalt pavements. Finally, some potential research directions are suggested for future research works.
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Affiliation(s)
| | | | - Ali Ghodrati
- School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
| | - Seyed Sina Sharifi
- School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
| | | | - Arman Ahmadi
- Department of Biological and Agricultural Engineering, University of California, Davis, USA
| | - Ehsan Vahidi
- Department of Mining and Metallurgical Engineering, Mackay School of Earth Sciences and Engineering, University of Nevada, Reno, USA
| | - Pooyan Ayar
- School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran.
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11
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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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12
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Oehmig WN, Roessler J, Saleh AM, Clavier KA, Ferraro CC, Townsend TG. Comparison of trace element mobility from MSWI ash before and after plasma vitrification. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2022; 40:227-235. [PMID: 33866877 DOI: 10.1177/0734242x211011543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
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.
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Affiliation(s)
- Wesley N Oehmig
- Department of Environmental Engineering, University of Florida, Gainesville, FL, USA
- HDR, Raleigh, NC, USA
| | - Justin Roessler
- Department of Environmental Engineering, University of Florida, Gainesville, FL, USA
- Pasco County Resource Recovery Facility, Spring Hill, FL, USA
| | - Abdul Mulla Saleh
- Pasco County Resource Recovery Facility, Spring Hill, FL, USA
- CDM Smith, Tampa, FL, USA
| | - Kyle A Clavier
- Department of Environmental Engineering, University of Florida, Gainesville, FL, USA
| | - Christopher C Ferraro
- Department of Civil & Coastal Engineering, University of Florida, Gainesville, FL, USA
| | - Timothy G Townsend
- Department of Environmental Engineering, University of Florida, Gainesville, FL, USA
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13
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Dhote L, Pandey RA, Middey A, Mandal N, Kumar S. Co-combustion of distillery sludge and coal for application in boiler and subsequent utilization of the generated bottom ash. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:36742-36752. [PMID: 33710486 DOI: 10.1007/s11356-021-13277-y] [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: 11/11/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Combustion stands as one of the essential methods in resource recovery for disposal of distillery sludge. In this study, sludge along with coal has been considered an option for co-combustion in the grate furnace aiming for further application as a boiler fuel. Detailed analysis was carried out to verify the feasibility of co-combustion of sludge with coal. Distillery sludge was blended with coal as a mixed fuel at co-combustion ratios of 20%, 30%, and 40% in grate furnace. The results of the analysis indicated that the combustion with 40% sludge mixed coal is suitable for application as a fuel in boiler. According to the chemical composition of bottom ash, weight loss from 460 to 800°C indicated the presence of C-C and C-H. Also, EDX and XRD analyses of mixed fuel was carried out to determine the mineralogical composition. The presence of quartz (SiO2), mullite (3Al2O32SiO2), and hematite (Fe2O3) present in the ash can be used as mineral additives in cement industries. The study also provided a promising approach towards diverting combustion bottom ash from landfills for its utilization in various industries which can be a possible cost-effective solution.
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Affiliation(s)
- Lekha Dhote
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 2010 02, India
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, 440 020, India
| | - Ram Avatar Pandey
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, 440 020, India
| | - Anirban Middey
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, 440 020, India
| | - Neelkamal Mandal
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, 440 020, India
| | - Sunil Kumar
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, 440 020, India.
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14
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Towards Sustainable Soil Stabilization in Peatlands: Secondary Raw Materials as an Alternative. SUSTAINABILITY 2021. [DOI: 10.3390/su13126726] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Implementation of construction works on weak (e.g., compressible, collapsible, expansive) soils such as peatlands often is limited by logistics of equipment and shortage of available and applicable materials. If preloading or floating roads on geogrid reinforcement or piled embankments cannot be implemented, then soil stabilization is needed. Sustainable soil stabilization in an environmentally friendly way is recommended instead of applying known conventional methods such as pure cementing or excavation and a single replacement of soils. Substitution of conventional material (cement) and primary raw material (lime) with secondary raw material (waste and byproducts from industries) corresponds to the Sustainable Development Goals set by the United Nations, preserves resources, saves energy, and reduces greenhouse gas emissions. Besides traditional material usage, soil stabilization is achievable through various secondary raw materials (listed according to their groups and subgroups): 1. thermally treated waste products: 1.1. ashes from agriculture production; 1.2. ashes from energy production; 1.3. ashes from various manufacturing; 1.4. ashes from waste processing; 1.5. high carbon content pyrolysis products; 2. untreated waste and new products made from secondary raw materials: 2.1. waste from municipal waste biological treatment and landfills; 2.2. waste from industries; 3. new products made from secondary raw materials: 3.1. composite materials. Efficient solutions in environmental engineering may eliminate excessive amounts of waste and support innovation in the circular economy for sustainable future.
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15
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Garrabrants AC, Kosson DS, Brown KG, Fagnant DP, Helms G, Thorneloe SA. Demonstration of the use of test results from the Leaching Environmental Assessment Framework (LEAF) to develop screening-level leaching assessments. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 121:226-236. [PMID: 33383531 PMCID: PMC10468778 DOI: 10.1016/j.wasman.2020.12.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 12/12/2020] [Indexed: 06/12/2023]
Abstract
Environmental management often benefits from leaching assessment as a predictive tool for estimating constituent leaching from solid and waste materials. The Leaching Environmental Assessment Framework (LEAF) provides both validated tests methods for characterizing materials and a methodology for developing screening assessments based on material characterization results. The use of LEAF data in a screening-level environmental assessment approach is demonstrated through a hypothetical case study of copper/lead smelter soil remediation. The LEAF test methods characterize leaching behavior from a wide range of materials as either constituent liquid-solid partitioning as functions of pH and liquid-to-solid ratio (L/S) or as a rate of constituent mass transport. In this study, leaching characteristics of a contaminated smelter soil and the same soil treated by solidification/stabilization with Portland cement were compared to hypothetical environmental thresholds. Screening assessments were developed for total content, available content, and maximum concentrations over relevant pH domains and L/S ranges. Assessment ratios for barium, beryllium, and fluoride indicated that estimated leaching would be less than thresholds in both materials and these constituents were removed from further analysis. Similarly, chromium (in soil) and zinc (in solidified material) were screened from further analysis. For the remaining constituents, scenario-based assessment could refine estimated leaching concentrations by considering anticipated conditions of leaching scenario.
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Affiliation(s)
- Andrew C Garrabrants
- Department of Civil and Environmental Engineering, Vanderbilt University, 2301 Vanderbilt Place, PMB-351826, Nashville, TN 37235, United States
| | - David S Kosson
- Department of Civil and Environmental Engineering, Vanderbilt University, 2301 Vanderbilt Place, PMB-351826, Nashville, TN 37235, United States.
| | - Kevin G Brown
- Department of Civil and Environmental Engineering, Vanderbilt University, 2301 Vanderbilt Place, PMB-351826, Nashville, TN 37235, United States
| | - Daniel P Fagnant
- Office of Land and Emergency Management, United States Environmental Protection Agency, Washington, DC, United States
| | - Gregory Helms
- Office of Land and Emergency Management, United States Environmental Protection Agency, Washington, DC, United States
| | - Susan A Thorneloe
- Office of Research and Development, United States Environmental Protection Agency, Durham, NC, United States
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16
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Sun X, Yi Y. Acid washing of incineration bottom ash of municipal solid waste: Effects of pH on removal and leaching of heavy metals. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 120:183-192. [PMID: 33310130 DOI: 10.1016/j.wasman.2020.11.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 09/29/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
This study systematically investigated the acid washing of incineration bottom ash (IBA) of municipal solid waste, focusing on the removal and leaching of heavy metals (Pb, Zn, Cr, Cd, Cu, and Ni), as well as their pH-dependent behavior. A series of small-scale laboratory acid washing tests with different nitric acid concentrations and washing periods were conducted. The concentrations of metals in the washing water were measured to evaluate the metal removal efficiency. Then, one stage batch leaching test was conducted for washed IBA to evaluate the leaching reduction efficiency of washing. The results showed that the maximum metal removal efficiencies for Zn, Cu, and Ni (62-76%) were higher than those for Pb, Cr, and Cd (17-25%), which were reached at the highest acid addition for most of the metals. Increasing the washing period did not always increase the metal removal efficiency. The maximum leaching reduction efficiencies were higher for Zn, Cr, and Cu (93-98%) than those for Pb, Ni, and Cd (73-79%). Both washing and leaching processes showed a similar metal concentration-pH profile for each metal. For Pb, Zn, Cr, and Cd, the metal concentration-pH profile generally followed the metal hydroxide solubility versus pH curves. For Cu and Ni, the concentration of metal decreased with the increasing pH first and then kept at a stable concentration higher than the solubility of the hydroxide, indicating that Cu and Ni in the IBA washing water and leachates did not exist dominantly as their hydroxides.
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Affiliation(s)
- Xinlei Sun
- School Civil and Environmental Engineering, Nanyang Technological University, Singapore
| | - Yaolin Yi
- School Civil and Environmental Engineering, Nanyang Technological University, Singapore.
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17
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Assessment of the Synergy between Recycling and Thermal Treatments in Municipal Solid Waste Management in Europe. ENERGIES 2020. [DOI: 10.3390/en13236412] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In 2018, the production of Municipal Solid Waste (MSW) in EU-28 reached 250.6 Mt, with the adoption of different management strategies, involving recycling (48 wt %), incineration and thermal valorization (29 wt %) and landfilling (23 wt %). This work was based on the analysis of the baseline situation of MSW management in EU-28 in 2018, considering its progress in 2008–2018, and discussed the possible improvement perspectives based on a framework involving incineration and recycling as the only possible alternatives, specifically evaluating the capability of already-existing incineration plants to fulfill the EU needs in the proposed framework. The results of the assessment showed two main crucial issues that could play a pivotal role in the achievement of Circular Economy action plan targets: the need to increase the recycling quotas for specific MSW fractions through the separate collection, and therefore the improvement of definite treatment process chains; the optimization of the recovery of secondary raw materials from incineration bottom ash, involving the recycling of ferrous and nonferrous metals and the mineral fraction. Both issues need to find an extensive application across all member states to decrease the actual differences in the adoption of sustainable MSW management options.
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