Closing Domestic Nutrient Cycles Using Microalgae.

Area of Science:

• Environmental Microbiology
• Biotechnology
• Wastewater Treatment

Background:

• Black water, a challenging wastewater stream, contains high concentrations of phosphorus (P) and nitrogen (N).
• Conventional wastewater treatment methods often struggle with efficient nutrient recovery and resource generation.

Purpose of the Study:

• To investigate the potential of microalgae for simultaneous nutrient recovery and biomass production from anaerobically treated black water.
• To evaluate the performance of specific microalgal strains in removing P and N.

Main Methods:

• Screening of green microalgae and cyanobacteria for growth on black water.
• Controlled experiments using Chlorella sorokiniana in flat-panel photobioreactors.
• Monitoring of P and N depletion, removal rates, and biomass yield.

Main Results:

• Chlorella sorokiniana achieved 100% removal of P and N from black water.
• P was depleted within 4 days; N depletion occurred within 12 days.
• High biomass concentration (11.5 g·L⁻¹) with significant P (1%) and N (7.6%) content was achieved.

Conclusions:

• Microalgae, particularly Chlorella sorokiniana, are highly effective for P and N recovery from black water.
• This process offers a sustainable solution for nutrient removal and valuable biomass generation.
• The findings support microalgae cultivation as a promising post-treatment strategy for black water.