Novel method to immobilize phosphate in lakes using sediment microbial fuel cells

Area of Science:

• Environmental Science
• Environmental Engineering
• Electrochemistry

Background:

• Phosphate pollution from sediment phosphorus is a major challenge for lake remediation.
• Existing methods struggle to address internal phosphorus loading from sediments.

Purpose of the Study:

• To investigate the use of sediment microbial fuel cells (SMFCs) for immobilizing phosphorus in lake sediments.
• To assess the scalability and practicality of SMFCs using low-cost materials for lake remediation.

Main Methods:

• SMFCs with stainless steel electrodes were tested in laboratory microcosms and a field-scale eutrophic lake.
• Electrode modifications included chronoamperometric operation, graphite slurry injection, and nickel-carbon coating.
• Sediment redox potential changes were monitored to assess phosphorus immobilization.

Main Results:

• Lab-scale tests showed an 85% decrease in overlying water phosphate using steel electrodes.
• Field-scale application achieved a maximum 94% phosphate decrease in the water body.
• SMFCs demonstrated potential for degrading organic matter and pollutants, and reducing gas emissions.

Conclusions:

• SMFCs offer a promising, low-cost solution for lake remediation by immobilizing sediment phosphorus.
• The technology is scalable and practical, with additional benefits like pollutant degradation and reduced greenhouse gas emissions.
• Further full-scale remediation trials are warranted based on these encouraging results.