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Wang H, Zhu F, Liu X, Han M, Zhang R. A mini-review of heavy metal recycling technologies for municipal solid waste incineration fly ash. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2021; 39:1135-1148. [PMID: 33818201 DOI: 10.1177/0734242x211003968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This mini-review article summarizes the available technologies for the recycling of heavy metals (HMs) in municipal solid waste incineration (MSWI) fly ash (FA). Recovery technologies included thermal separation (TS), chemical extraction (CE), bioleaching, and electrochemical processes. The reaction conditions of various methods, the efficiency of recovering HMs from MSWI FA and the difficulties and solutions in the process of technical development were studied. Evaluation of each process has also been done to determine the best HM recycling method and future challenges. Results showed that while bioleaching had minimal environmental impact, the process was time-consuming. TS and CE were the most mature technologies, but the former process was not cost-effective. Overall, it has the greatest economic potential to recover metals by CE with scrubber liquid produced by a wet air pollution control system. An electrochemical process or solvent extraction could then be applied to recover HMs from the enriched leachate. Ongoing development of TS and bioleaching technologies could reduce the treatment cost or time.
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Affiliation(s)
- Huan Wang
- Department of Environmental Engineering, School of Environment & Natural Resources, Renmin University of China, Beijing, People's Republic of China
| | - Fenfen Zhu
- Department of Environmental Engineering, School of Environment & Natural Resources, Renmin University of China, Beijing, People's Republic of China
| | - Xiaoyan Liu
- Department of Environmental Engineering, School of Environment & Natural Resources, Renmin University of China, Beijing, People's Republic of China
| | - Meiling Han
- Department of Environmental Engineering, School of Environment & Natural Resources, Renmin University of China, Beijing, People's Republic of China
| | - Rongyan Zhang
- Department of Environmental Engineering, School of Environment & Natural Resources, Renmin University of China, Beijing, People's Republic of China
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Markphan W, Mamimin C, Suksong W, Prasertsan P, O-Thong S. Comparative assessment of single-stage and two-stage anaerobic digestion for biogas production from high moisture municipal solid waste. PeerJ 2020; 8:e9693. [PMID: 32879796 PMCID: PMC7443091 DOI: 10.7717/peerj.9693] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 07/20/2020] [Indexed: 11/20/2022] Open
Abstract
Background Anaerobic digestion (AD) is a suitable process for treating high moisture MSW with biogas and biofertilizer production. However, the low stability of AD performance and low methane production results from high moisture MSW due to the fast acidify of carbohydrate fermentation. The effects of organic loading and incineration fly ash addition as a pH adjustment on methane production from high moisture MSW in the single-stage AD and two-stage AD processes were investigated. Results Suitable initial organic loading of the single-stage AD process was 17 gVS L-1 at incineration fly ash (IFA) addition of 0.5% with methane yield of 287 mL CH4 g-1 VS. Suitable initial organic loading of the two-stage AD process was 43 gVS L-1 at IFA addition of 1% with hydrogen and methane yield of 47.4 ml H2 g-1 VS and 363 mL CH4 g-1 VS, respectively. The highest hydrogen and methane production of 8.7 m3 H2 ton-1 of high moisture MSW and 66.6 m3 CH4 ton-1 of high moisture MSW was achieved at organic loading of 43 gVS L-1 at IFA addition of 1% by two-stage AD process. Biogas production by the two-stage AD process enabled 18.5% higher energy recovery than single-stage AD. The 1% addition of IFA into high moisture MSW was useful for controlling pH of the two-stage AD process with enhanced biogas production between 87-92% when compared to without IFA addition. Electricity production and energy recovery from MSW using the coupled incineration with biogas production by two-stage AD process were 9,874 MJ ton-1 MSW and 89%, respectively. Conclusions The two-stage AD process with IFA addition for pH adjustment could improve biogas production from high moisture MSW, as well as reduce lag phase and enhance biodegradability efficiency. The coupled incineration process with biogas production using the two-stage AD process was suitable for the management of MSW with low area requirement, low greenhouse gas emissions, and high energy recovery.
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Affiliation(s)
- Wattananarong Markphan
- Environmental Program, Faculty of Sciences and Technology, Nakhon Si Thammarat Rajabhat University, Nakhon Si Thammarat, Thailand
| | - Chonticha Mamimin
- Research and Development Office, Prince of Songkla University, Songkhla, Thailand
| | - Wantanasak Suksong
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Poonsuk Prasertsan
- Research and Development Office, Prince of Songkla University, Songkhla, Thailand
| | - Sompong O-Thong
- International College, Thaksin University, Songkhla, Thailand.,Sustainable Agricultural Resources Management Program, Faculty of Technology and Community Development, Thaksin University, Phatthalung, Thailand
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Xie K, Hu H, Cao J, Yang F, Liu H, Li A, Yao H. A novel method for salts removal from municipal solid waste incineration fly ash through the molten salt thermal treatment. CHEMOSPHERE 2020; 241:125107. [PMID: 31683450 DOI: 10.1016/j.chemosphere.2019.125107] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/07/2019] [Accepted: 10/12/2019] [Indexed: 06/10/2023]
Abstract
The disposal of the hazardous municipal solid waste (MSW) incineration fly ash is a critical environmental issue in China and the high contents of salts in the fly ash make the ash disposal extremely difficult. The present study proposes a novel method for the salts removal from MSW incineration fly ash using molten carbonates and chlorides at moderate temperatures from 773 K to 1073 K. The results showed that molten salts could effectively extract alkali and alkaline earth metals chlorides and sulfates from the fly ash. Other ash components, like Si/Al-compounds, were precipitated from the molten salts and concentrated in residues. By comparison, molten carbonates showed greater capability in the salts extraction while molten chlorides showed better selectivity in chlorides removal from MSW incineration fly ash. These findings suggest that the optimization of molten salts system could further prove the potential applicability of molten salts thermal treatment method for the salts removal from MSW incineration fly ash.
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Affiliation(s)
- Kang Xie
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Hongyun Hu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Jinxiu Cao
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Fu Yang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Huan Liu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China; Department of New Energy Science and Engineering, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Aijun Li
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China; Department of New Energy Science and Engineering, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Hong Yao
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China; Department of New Energy Science and Engineering, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
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Yu J, Sun L, Ma C, Qiao Y, Xiang J, Hu S, Yao H. Mechanism on heavy metals vaporization from municipal solid waste fly ash by MgCl₂⋅6H₂O. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 49:124-130. [PMID: 26748437 DOI: 10.1016/j.wasman.2015.12.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/21/2015] [Accepted: 12/19/2015] [Indexed: 06/05/2023]
Abstract
This work aims to study the mechanism of heavy metals vaporization by MgCl2⋅6H2O. Firstly, the decomposition mechanism of MgCl2⋅6H2O was investigated by thermodynamic equilibrium calculations, XRD and TG. Upon heating, MgCl2⋅6H2O went through the processes of dehydration and hydrolysis simultaneously accompanied by the release of HCl between 150 and 500°C. At temperature higher than 500°C, Mg(OH)Cl gradually release part of HCl. MgCl2⋅6H2O followed the similar processes of decomposition at both oxidative and reductive atmospheres. In oxidative atmosphere, vaporization of Zn and Cu was significantly accelerated by MgCl2⋅6H2O. However, in inert atmosphere, vaporization of Cu was not promoted since copper chloride was only stable in oxidative atmosphere. Under slow heating condition, vaporization of heavy metals were close to that under fast heating condition. This may be partially attributed to that most heavy metals already reacted with HCl forming metal chlorides below 500°C, which can be vaporized at higher temperature. Moreover, the Mg(OH)Cl contributed to release HCl up to 800°C. At such high temperature, the metal chlorides continue to be formed and then vaporized. After treatment, the leaching concentration of heavy metals from treated fly ashes were much lower than that from raw fly ash and met the regulatory limit of leachate. Since a large amount of MgSiO3 were formed during thermal treatment, the fly ash treated with MgCl2⋅6H2O can be used as raw materials for glass-ceramics production.
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Affiliation(s)
- Jie Yu
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China
| | - Lushi Sun
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China.
| | - Chuan Ma
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China
| | - Yu Qiao
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China
| | - Jun Xiang
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China
| | - Song Hu
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China
| | - Hong Yao
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 430074 Wuhan, Hubei, China
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