Innovative microalgae biomass harvesting methods: Technical feasibility and life cycle analysis.

Area of Science:

• Environmental Science
• Biotechnology
• Chemical Engineering

Background:

• Biomass production in wastewater faces challenges, particularly during the harvesting stage.
• Efficient biomass harvesting is crucial for its subsequent use in bioproducts and bioenergy.

Purpose of the Study:

• To compare the technical and environmental performance of different biomass harvesting methods.
• To project an optimal environmental scenario for biomass harvesting from wastewater.

Main Methods:

• Evaluated three harvesting methods: gravitational sedimentation (GS), coagulation with tannin followed by gravitational sedimentation (TC/GS), and a biofilm reactor with gravitational sedimentation (BR/GS).
• Assessed technical parameters like concentration time and moisture content.
• Conducted a life cycle assessment (LCA) to determine environmental impacts.

Main Results:

• TC/GS required less time for biomass concentration but resulted in higher moisture content (99.02%).
• Harvesting methods influenced biomass composition, with higher carbohydrate content (28-37%) in biomass concentrated over time compared to coagulation (13.8%).
• LCA indicated lower environmental impact for TC/GS and BR/GS compared to GS alone.

Conclusions:

• The combination of TC/GS and BR/GS presents the most optimal environmental scenario for biomass harvesting.
• These advanced methods can significantly optimize biomass recovery from wastewater, improving its potential for bio-based applications.