Hybrid microalgae-activated sludge system for carbon-efficient wastewater treatment

Area of Science:

• Environmental Science
• Biotechnology
• Chemical Engineering

Background:

• Wastewater treatment faces challenges in energy consumption and carbon emissions.
• Microalgae-bacteria systems present a promising avenue for sustainable solutions.
• Integrating carbon capture with wastewater treatment is crucial for environmental goals.

Purpose of the Study:

• To develop and evaluate a hybrid microalgae-activated sludge (HMAS) system.
• To couple carbon capture with domestic wastewater treatment.
• To assess the energy efficiency and operational cost savings of the HMAS system.

Main Methods:

• Utilized photobioreactors with red light-emitting diodes (LEDs).
• Inoculated with a mixed microbial culture for a hybrid microalgae-activated sludge system.
• Treated synthetic municipal wastewater in a chemostat for two months under specific conditions (600 μmol/m² s irradiance, 250 mg/L SCOD, 90 mg/L NH₃-N, 10 mg/L orthophosphate, 25 mL/min CO₂ supply).

Main Results:

• Achieved efficient removal of soluble chemical oxygen demand (SCOD) up to 70%.
• Microalgal photosynthesis met the bacterial oxygen requirement (>2 mg/L).
• Demonstrated substantial savings in operational costs due to LED illumination.

Conclusions:

• The hybrid microalgae-activated sludge system is effective for carbon-efficient wastewater treatment.
• This technology offers a sustainable approach to managing domestic wastewater.
• The system shows potential for energy-efficient and carbon-neutral wastewater treatment solutions.