Biohydrogen production coupled with wastewater treatment using selected microalgae.

Area of Science:

• Biotechnology
• Environmental Science
• Renewable Energy

Background:

• Microalgae cultivation in wastewater offers a dual benefit of resource recovery and biofuel production.
• Domestic wastewater presents a potential substrate for microalgal growth and subsequent biohydrogen generation.

Purpose of the Study:

• To compare the biomass production, biochemical yields, and nutrient removal efficiencies of Chlorella pyrenoidosa, Scenedesmus obliquus, and Chlorella sorokiniana grown in domestic wastewater.
• To evaluate the biohydrogen production potential from the cultivated microalgal biomass.

Main Methods:

• Cultivation of three microalgal species in domestic wastewater.
• Analysis of biomass production, protein, lipid, and carbohydrate content.
• Assessment of nutrient removal efficiencies (nitrate, nitrite, ammonia, phosphorus).
• Acid pre-treatment of microalgal biomass followed by dark fermentation for hydrogen production.

Main Results:

• Scenedesmus obliquus demonstrated superior performance in biomass production (0.90 g/L), protein content (35.76%), and nutrient removal.
• All tested microalgae achieved high biomass yields (0.71-0.90 g/L) and comparable lipid (25.34-26.23%) and carbohydrate (30.32-33.21%) content.
• Chlorella pyrenoidosa yielded the highest biohydrogen production (45.50 mL H2/gVS) after biomass pre-treatment and dark fermentation.

Conclusions:

• Microalgal cultivation in domestic wastewater is a viable strategy for simultaneous wastewater treatment and biomass generation.
• The generated microalgal biomass can be effectively converted into biohydrogen, contributing to sustainable energy solutions.
• Scenedesmus obliquus shows significant promise for wastewater-based cultivation and resource recovery.