Ex Situ Stabilization/Solidification Approaches of Marine Sediments Using Green Cement Admixtures

Area of Science:

• Environmental Engineering
• Geochemistry
• Materials Science

Background:

• Dredging generates large volumes of sediments, often contaminated with heavy metals.
• Handling and disposal of contaminated dredged sediments present global environmental challenges.

Purpose of the Study:

• To review cement-based binders for stabilizing contaminants in dredged sediments.
• To explore the utilization of contaminated sediments as a resource through stabilization/solidification (S/S).

Main Methods:

• Focus on stabilization/solidification (S/S) techniques using cement-based binders.
• Investigating industrial by-products (red mud, soda residue, fly ash, slag) for heavy metal immobilization.
• Examining low pH media and pozzolanic reactions for enhanced stabilization.

Main Results:

• S/S techniques solidify heavy metals into durable matrices, reducing environmental release.
• Industrial by-products can immobilize heavy metals like lead, zinc, cadmium, copper, and chromium via precipitation.
• Low pH media and pozzolanic reactions (silicate gels, ettringites) offer alternative immobilization mechanisms.

Conclusions:

• Cement-based binders offer a sustainable approach to remediating contaminated dredged sediments.
• Further multidisciplinary research is needed on novel materials for long-term heavy metal stabilization.
• Contaminated sediments can be repurposed as a resource through effective S/S treatment.