ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Earth and Planetary Materials
Volume 13 - 2025 | doi: 10.3389/feart.2025.1605262
This article is part of the Research TopicAdvances in Structure, Characterization, and Failure Mechanisms of Geomaterials: Theoretical, Experimental, and Numerical ApproachesView all 13 articles
Time-Dependent Effects of Calcium Oxide on Urban Sludge Dewatering in Temporary Lagoons and Its Application in Sustainable Urban Development
Provisionally accepted
- 1China Railway 15th Bureau Group Co. Ltd, Shanghai, China
- 2China Railway Construction Corporation Limited, Beijing, China
- 3College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, Liaoning Province, China
- 4Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Liaoning Province, China
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Calcium oxide (CaO) was used to condition urban sludge, with a focus on the impact of conditioning time, and its potential application in sustainable urban development was explored. In this study, the volume reduction ratio (VRR) was employed as the primary evaluation metric, and response surface methodology (RSM) was applied to investigate the combined effects of CaO dosage and conditioning time on sludge dewaterability. The optimal process conditions were determined, and the dewatering mechanism was analyzed. Results showed that the interaction between CaO dosage and conditioning time significantly influenced sludge dewatering performance.Under optimal conditions -0.48 g/g dry solids (DS) of CaO and 14.35 hours of conditioning，the volume reduction ratio of sludge reached 72.76±0.56%. Mechanistic analysis revealed that CaO conditioning promotes the embedding of calcium-based compounds into sludge flocs, forming a rigid skeletal structure that facilitates internal water release. These effects enhance with increasing conditioning time up to a certain threshold, thereby significantly improving sludge dewaterability. The findings highlight the potential of CaO conditioning as an effective strategy for sludge management in temporary lagoons and its broader implications for sustainable urban development.
Keywords: CaO, Conditioning time, Deep dewatering, Temporary sludge lagoons, Response Surface Methodology, Volume reduction ratio, Filtrate pH, sustainable development
Received: 03 Apr 2025; Accepted: 20 Jun 2025.
Copyright: © 2025 Zhou, Huang, Wang, Zhao, Luan and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Changfu Huang, China Railway Construction Corporation Limited, Beijing, China
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