Microalga-Mediated Tertiary Treatment of Municipal Wastewater: Removal of Nutrients and Pathogens

The microalgal strain Chlorella sorokiniana isolated from a waste stabilization pond was used for tertiary treatment of municipal wastewater. Three light:dark (L:D) regimes 12:12, 16:8, and 24:0 were treating wastewater in microalga (A), + sludge (A S), (S) reactors. removal nutrients (N P) found to be the highest microalga-based reactor, with more than 80% biochemical oxygen demand (BOD) 1.2–5.6 log unit pathogens. addition improved chemical (COD) removal. Nitrifiers predominant A S reactor. Algal biomass productivity 280 mg/L/d all L:D regimes. increase light regime nutrient algal Results kinetic study showed that (i) nitrifiers had affinity ammonium microalga, hence, most ammonia oxidized nitrate, (ii) assimilated nitrate as primary nitrogen source (iii) solubilization particulate organic originated dead cells reduced efficiency. However, uptake higher uptake. Among pathogens, Salmonella Shigella better reactor other two reactors (microalga reactor). Additionally, heterotrophic plate count drastically presence microalga. No such drastic reduction observed stand-alone Kinetic modeling revealed microalga–pathogen competition pH-induced die-off factors pathogen inactivation.