Simultaneous algae-polluted water treatment and electricity generation using a biocathode-coupled electrocoagulation...

Area of Science:

• Environmental Engineering
• Electrochemistry
• Microbiology

Background:

• Electrocoagulation (EC) is energy-intensive, limiting its use for algae-polluted water.
• Developing energy-efficient water treatment technologies is crucial.

Purpose of the Study:

• To develop a novel biocathode-coupled electrocoagulation cell (bio-ECC) for energy-efficient algae removal.
• To assess the bio-ECC's performance in algae and ammonium removal, and energy recovery.

Main Methods:

• Constructed a bio-ECC with a sacrificial iron anode and a nitrifying biocathode.
• Tested the bio-ECC under varying solution conductivities.
• Analyzed algae removal efficiency, power generation, and ammonium removal rates.
• Utilized pyrosequencing to identify microbial communities in the biocathode.
• Employed AFM and SEM-EDX to investigate algae removal mechanisms.

Main Results:

• Achieved near-complete algae cell removal across different conductivities.
• Generated significant power densities (8.41–11.33 Wm^-3) with positive energy balance (4.52–7.44 Wm^-3).
• Demonstrated excellent ammonium-nitrogen removal rates (6.77–7.28 mgL^-1h^-1).
• Identified enriched nitrifying bacteria (Nitrospira, Nitrobacter, Nitrosococcus, Nitrosomonas) in the biocathode.

Conclusions:

• The bio-ECC transforms energy-intensive EC into an energy-neutral process.
• Offers high-efficiency algae removal, electricity recovery, and nitrogen removal.
• Provides a viable, sustainable solution for treating algae-polluted water.