Electrochemically-assisted ammonia recovery from wastewater using a floating electrode

Area of Science:

• Environmental Science
• Electrochemistry
• Water Treatment

Background:

• Ammonia contamination in wastewater poses significant environmental and health risks.
• Conventional ammonia removal methods can be energy-intensive or inefficient.

Purpose of the Study:

• To develop and evaluate a novel electrochemical methodology for ammonia removal and recovery from wastewater.
• To investigate the combined mechanisms of electrochemical oxidation and electrochemically-assisted surface transfer for ammonia management.

Main Methods:

• Utilizing a floating cathodic electrode at the wastewater-air interface to facilitate ammonia transfer.
• Employing anodic reactions for ammonia oxidation within the wastewater bulk.
• Testing the system on synthetic wastewater and filtered anaerobic centrate.

Main Results:

• Achieved near-linear reductions in dissolved ammonium concentrations.
• Demonstrated significant ammonia recovery without ion-exchange membranes.
• Observed high removal rates: up to 216 mg l⁻¹ hr⁻¹ in synthetic wastewater and 110 mg l⁻¹ hr⁻¹ in anaerobic centrate at 5 mA cm⁻².

Conclusions:

• The floating electrode approach offers an efficient and membrane-free method for ammonia removal and recovery.
• This technology is suitable for high-ammonia wastewaters like anaerobic digester centrate and urine.
• Potential applications include municipal, industrial, and environmental water treatment.