Mixture design and treatment methods for recycling contaminated sediment

Area of Science:

• Environmental Engineering
• Materials Science
• Geotechnical Engineering

Background:

• Marine disposal of contaminated sediment incurs substantial financial and environmental costs.
• Developing sustainable methods for contaminated sediment management is crucial.

Purpose of the Study:

• To investigate the recycling of contaminated sediment into construction materials through stabilization/solidification.
• To assess the impact of binder formulation, pretreatment, curing, and waste inclusion on sediment block properties.

Main Methods:

• Stabilization/solidification of sediment using cement, coal fly ash, and lime.
• Evaluating binder-to-sediment ratios and incorporating granular waste materials.
• Employing thermal pretreatment and CO2 curing methods.
• Analyzing compressive strength, X-ray diffraction, and thermogravimetric analysis.

Main Results:

• Sediment blocks with partial cement replacement (using coal fly ash and lime) achieved adequate compressive strength for fill materials.
• Thermal pretreatment removed 90% of organic matter, significantly boosting strength for masonry applications.
• CO2 curing accelerated carbonation, sequestered 5.6% CO2, and yielded strength comparable to 7-day curing.
• Incorporating granular waste materials enhanced sediment block strength, with minimal metal leachability.

Conclusions:

• Contaminated sediment can be effectively recycled into valuable construction resources.
• Optimized stabilization/solidification techniques, including pretreatment and CO2 curing, are key to successful sediment reuse.
• This approach offers a sustainable alternative to conventional marine disposal, mitigating environmental and financial burdens.