Marine mud is generated in large quantities during dredging, coastal development, land reclamation, and marine construction. In fast-growing urban regions, this sediment can become a major waste-management burden because it is wet, sticky, difficult to handle, and often contaminated with heavy metals. Conventional stabilization methods usually rely heavily on Portland cement, which is effective but energy-intensive and carbon-heavy. Alternative geopolymer approaches are promising, yet many still depend on corrosive or costly activators and do not always immobilize contaminants well enough. Based on these challenges, there is a pressing need to carry out in-depth research on low-carbon, practical, and safe strategies for the remediation and in-situ reuse of contaminated marine mud.
A team from Harbin Institute of Technology, Tsinghua University Shenzhen International Graduate School, the University of Abomey-Calavi, and the Beninese Office for Geological and Mining Research reported (DOI: 10.1007/s11783-026-2122-z) online on January 10, 2026, in ENGINEERING Environment that contaminated marine mud can be remediated and recycled in situ into engineered backfill materials using low-carbon formulations built around aluminosilicate raw materials.
To build a treatment route that was both effective and realistic, the researchers designed the work in stages. They collected marine mud from a construction site in Macao, then tested blends containing Portland cement, fly ash, slag, river sand, water, and low-concentration NaOH. The goal was not simply to harden the mud, but to find a mix that could improve strength, suppress heavy-metal release, and remain practical for large-scale site use. After preparing and curing the samples, the team evaluated compressive strength, unconfined compressive strength, leaching toxicity, and microstructural characteristics through XRF, XRD, SEM, and TEM analyses. The strongest optimized mixtures achieved unconfined compressive strengths (UCS) values of 7.75 MPa with 25% OPC, 4.24 MPa with fly ash, 8.69 MPa with slag, and 3.15 MPa with a river-sand formulation—each above the 1 MPa benchmark for backfill application. At the same time, the treatment sharply reduced the leaching of As, Ba, Cd, Cr, and Pb, with Pb completely removed in all mixtures. XRD and morphological analyses further showed that the stabilized mud developed mineral and gel phases dominated by SiO2, Ca(CO3), Mn1.7Fe1.3O4, and complex silicate structures, which helped explain the improved strength and contaminant immobilization.
“This work shows that contaminated marine mud does not have to remain an environmental liability,” the study suggests in essence. By replacing more carbon-intensive treatment approaches with lower-carbon mineral formulations, the research reframes marine sediment as a reusable resource rather than a disposal problem. Just as importantly, the team designed the system with real construction conditions in mind, including the use of locally available river sand and simplified activation chemistry. That practical orientation makes the study especially valuable for coastal cities facing both land scarcity and mounting waste-treatment costs.
The implications extend beyond one sediment stream. This research offers a route toward cleaner coastal engineering, lower landfill dependence, and more circular use of waste materials in infrastructure projects. For regions where marine mud accounts for a large share of construction waste, in-situ recycling could ease pressure on disposal sites while cutting transport and treatment expenses. The study also aligns with wider carbon-reduction goals by reducing reliance on traditional cement-heavy stabilization. In the longer term, such low-carbon remediation systems could help cities manage contaminated sediments more safely while turning them into useful materials for backfilling, site restoration, and future sustainable construction applications.
###
References
DOI
10.1007/s11783-026-2122-z
Original Source URL
https://doi.org/10.1007/s11783-026-2122-z
Funding Information
This work was supported by Guangdong Basic and Applied Basic Research Foundation, China (No. 2022B1515130006). Acknowledgements are also given to Shenzhen Science and Technology Program: Sustainable Development Special Project (No.KCXST20221021111408021) and International Collaboration Project (No. GJHZ20220913143007013).
About ENGINEERING Environment
ENGINEERING Environment is an international journal in environmental disciplines, jointly sponsored by the Chinese Academy of Engineering, Tsinghua University, and Higher Education Press. The journal is dedicated to advancing and disseminating the discoveries of cutting-edge theories, innovations in engineering technology, and practices in technological application within the environmental discipline. Adhering to the principle of integrating scientific theories with engineering technologies, the journal emphasizes the convergence of environmental protection with One Health, climate change response, and sustainable development. It places particular emphasis on the forward-looking nature of novel technologies and emerging challenges, the practicality of solutions, and interdisciplinary innovations.