Biotratamiento de efluentes secundarios municipales utilizando microalgas: Efecto del pH, nutrientes (C, N y P) y enriquecimiento con CO2

Abstract

This review discusses microalgae assimilation of C, N and P as affected by pH-dependent factors (solubility, ionization state and bioavailability) and CO2 enrichment in tertiary water treatment during microalgae biomass production. This study indicates the importance of monitoring critical conditions such as: 1) pH and inorganic carbon species interaction; 2) P bioavailability; 3) nitrogen removal through NH3 volatilization and 4) NH3 toxicity. Also, optimal CO2 enriched air considerations, such as: 1) combining intermittent and variable CO2 enrichment to avoid losses into the atmosphere; 2) preventing microalgae growth inhibition due to H2CO3 formation and pH acidification at early stages of the culture and 3) maintenance of optimal pH (≈ 8.5) through the buffer system (CO2/ HCO3-). Finally, we suggest that biological technologies based on microalgae culture to remove excessive nutrient loads and compliance with environmental laws from water, represent a viable alternative attached to recycling and revaluation of resources through the generation and potential uses of biomass (e.g., fertilizer, pigments and antioxidants).