Utilizing a granulated coal bottom ash and oyster shells for nutrient removal in eutrophic sediments

Area of Science:

• Environmental Science
• Marine Biology
• Geochemistry

Background:

• Coastal sediments are often contaminated, impacting ecosystem health.
• In-situ capping materials are crucial for sediment remediation.
• Nutrient pollution, particularly phosphate and silicate, is a major concern in coastal areas.

Purpose of the Study:

• To develop and evaluate Granulated coal bottom ash and oyster shells (GBO) as an in-situ capping material.
• To determine the nutrient-removal efficiency of GBO in eutrophic coastal sediments.
• To identify the optimal mixing ratio of coal bottom ash and oyster shells for remediation.

Main Methods:

• Granulated coal bottom ash and oyster shells (GBO) were produced using pyrolyzed and grounded materials.
• GBO was tested as an in-situ capping material in long-term mesocosm experiments.
• Pore water concentrations of phosphate (PO4-P) and silicate (SiO2-Si) were measured to assess nutrient removal.

Main Results:

• GBO demonstrated significant nutrient-removal abilities in eutrophic coastal sediments.
• Phosphate-P concentrations in pore water decreased by 88.4%.
• Silicate-Si concentrations in pore water decreased by 56.5% with the optimal GBO mixture.

Conclusions:

• Granulated coal bottom ash and oyster shells (GBO) are effective in-situ capping materials for eutrophic coastal sediment remediation.
• The optimal weight ratio for GBO was determined to be 1:1 for both phosphate and silicate removal.
• GBO shows promise for restoring and sustaining healthy coastal ecosystems.