Overcoming Microalgae Harvesting Barrier by Activated Algae Granules.

Area of Science:

• Environmental biotechnology
• Wastewater treatment technologies
• Microalgae cultivation and harvesting

Background:

• The economic viability of microalgae-based wastewater treatment is hindered by costly harvesting methods.
• Conventional microalgae-bacteria flocs present challenges in efficient separation and recovery.

Purpose of the Study:

• To develop an alternative microalgae-bacteria system for cost-effective microalgae harvesting.
• To create activated algae granules using Chlorella sp. and Phormidium sp. for improved harvesting efficiency.

Main Methods:

• Investigated the granulation process of microalgae-bacteria consortia.
• Utilized filamentous Phormidium sp. to facilitate the capture of target microalgae Chlorella sp.
• Characterized the size, structure, and settling velocity of the developed activated algae granules.

Main Results:

• Successfully formed activated algae granules (600–2,000 µm) with compact structures and high settling velocities (21.6 ± 0.9 m/h).
• Achieved over 99% recovery of microalgae solely through rapid sedimentation of the granules.
• Demonstrated the elimination of cost and energy inputs for microalgae harvesting.

Conclusions:

• The activated algae granular system offers a viable and economical solution for microalgae harvesting in wastewater treatment.
• This granulation approach significantly enhances microalgae recovery efficiency, paving the way for scalable microalgae technology.