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Wu S, Peng X, Sun X, Dong Z, Zhou A, Zhang L, Wang R. One-step processing of waste dredged slurry into planting soil by targeted pretreatment and vacuum filtration. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 349:119334. [PMID: 37918235 DOI: 10.1016/j.jenvman.2023.119334] [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: 08/15/2023] [Revised: 09/29/2023] [Accepted: 10/12/2023] [Indexed: 11/04/2023]
Abstract
A novel method, targeted pretreatment and vacuum filtration (TP-VF), is introduced and validated in this study. TP-VF offers a one-step solution for efficiently dewatering dredged slurry (DS) characterized by heavy metal contamination, high salinity, and excessive moisture content. This innovative approach combines targeted pretreatment (TP) and vacuum filtration (VF) to transform DS into the viable planting soil. TP encompasses a dual optimization strategy that enhances both slurry dewatering efficiency and the quality of the resultant planting soil (cake). By employing flocculation pretreatment, TP increases the size of flocs and enlarges cake pores, leading to improvements in dewatering efficiency and infiltration rates. Additionally, targeted pretreatment results in the discharge of approximately 90% of heavy metal ions and most salts with the filtrate. Remarkably, the addition of chelating agents and freshwater as part of the pretreatment process positively impacts soil quality without compromising floc size or dewatering efficiency. Comparatively, TP-VF demonstrates a substantial reduction of 35.81% in operational costs when contrasted with the traditional two-step process, concurrently diminishing the potential for secondary environmental pollution. This study highlights TP-VF as a promising advancement in sustainable slurry management, addressing pressing environmental challenges while optimizing resource utilization.
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Affiliation(s)
- Silin Wu
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China; Shenzhen Key Laboratory of Green, Efficient and Intelligent Construction of Underground Metro Station, Shenzhen, 518060, China
| | - Xiao Peng
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China
| | - Xiaohui Sun
- Shenzhen Key Laboratory of Green, Efficient and Intelligent Construction of Underground Metro Station, Shenzhen, 518060, China; College of Civil and Transportation Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Zijun Dong
- Shenzhen Key Laboratory of Green, Efficient and Intelligent Construction of Underground Metro Station, Shenzhen, 518060, China; College of Civil and Transportation Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Aizhao Zhou
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China
| | - Lei Zhang
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China
| | - Ruochen Wang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China
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Liu Z, Wu S, Zhou A, Sun X, Xu H, Dong S. New insight into the additives in preparation and reduction of shield slurry. Sci Rep 2023; 13:15969. [PMID: 37749126 PMCID: PMC10519938 DOI: 10.1038/s41598-023-42939-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 09/16/2023] [Indexed: 09/27/2023] Open
Abstract
In the preparation of the slurry in the slurry shield (SSS) and subsequent reduction of the waste slurry produced by the slurry shield (WSSS), the additives in SSS improve the quality of filtration cake on the excavation surface, but they may also remain in WSSS, which have a negative impact on the reduction efficiency of WSSS. Therefore, it is valuable to establish the relationship between SSS and WSSS with additives as a link. Given this, this paper prepared WSSS with different dosages of additives and studied the influence of residual additives on the reduction. The residual additives made the reduction efficiency of WSSS worse, and the specific resistance to filtration increased by one to two orders of magnitude. The residual additives change the content of bound water or reduce the available sites of the soil particles that can be adsorbed by flocculants, leading to worse reduction results. To reduce the difficulty of reduction, combining polymer and bentonite as additives are recommended to prepare SSS. Polyaluminium chloride (PAC) acts by reducing bound water content through the interaction with residual bentonite, simultaneously augmenting PAM flocculation, which is recommended for reducing WSSS. This paper provides a reference for selecting materials used to prepare SSS and the subsequent reduction of WSSS.
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Affiliation(s)
- Zhitao Liu
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China
- Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China
| | - Silin Wu
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China.
- Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China.
- Shenzhen Key Laboratory of Green, Efficient and Intelligent Construction of Underground Metro Station, Shenzhen, 518060, China.
| | - Aizhao Zhou
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China
- Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China
| | - Xiaohui Sun
- Shenzhen Key Laboratory of Green, Efficient and Intelligent Construction of Underground Metro Station, Shenzhen, 518060, China
- College of Civil and Transportation Engineering, The Underground Polis Academy, Shenzhen University, Shenzhen, 518060, China
| | - Haoqing Xu
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China
- Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China
| | - Shutong Dong
- School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China
- Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation, Zhenjiang, 212100, China
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Jiang L, Zhen L, Wang J, Zhang T, Huang X. Research on Dewatering Characteristics of Waste Slurry from Pipe Jacking Construction. MATERIALS 2022; 15:ma15062242. [PMID: 35329695 PMCID: PMC8951550 DOI: 10.3390/ma15062242] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/12/2022] [Accepted: 03/15/2022] [Indexed: 12/10/2022]
Abstract
A large amount of waste slurry is produced during the construction of pipe jacking projects. To avoid the waste slurry occupying too much urban land, it needs to be rapidly reduced. Due to the complex composition of waste slurry, the existing dewatering methods face the problem of low efficiency, and the soil after dewatering is difficult to recycle as soil materials due to high water content and low strength. There is currently a lack of research on dewatering and resource utilization of waste slurry from pipe jacking projects. In response to this problem, this paper studies the flocculation-settling characteristics of waste slurry and the mechanical properties of solidified sediment. It was found that the anionic polyacrylamide (APAM) 7126 obtained the best separation effect if the waste slurry contains bentonite, which increases the zeta potential, resulting in poor separation. Thus, FeCl3·6H2O and APAM 7126 can be used as compound conditioners. The sediment after settling was further added with 20–30% sulphate aluminum cement (SAC), and the unconfined compressive strength of the solidified sediment for 3 days could exceed 30 kPa. After flocculation-settling and solidification treatment, the waste pipe jacking slurry can be quickly dewatered into a soil material with a certain strength, which provides a reference for engineering applications.
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Affiliation(s)
- Libing Jiang
- Water Supply and Drainage Management Office, Zhenjiang 212008, China;
| | - Liang Zhen
- Shanghai Road and Bridge (Group) Co., Ltd., Shanghai 200433, China; (J.W.); (T.Z.)
- Correspondence: (L.Z.); (X.H.)
| | - Jianfeng Wang
- Shanghai Road and Bridge (Group) Co., Ltd., Shanghai 200433, China; (J.W.); (T.Z.)
| | - Tao Zhang
- Shanghai Road and Bridge (Group) Co., Ltd., Shanghai 200433, China; (J.W.); (T.Z.)
| | - Xianwen Huang
- School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan 232001, China
- Correspondence: (L.Z.); (X.H.)
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