Microalgae cultivation is an ecological alternative to activated sludge-based technology, in which aerobic bacteria carry out wastewater treatment. Conventional treatment using activated sludge implies a high energy consumption due to the aeration necessary for the activity of bacteria. As an alternative, microalgae reduce costs since they generate oxygen via photosynthesis.
Synergies between microalgae and bacteria for wastewater treatment have been observed in several studies. However, this bioprocess still requires a better understanding of the interactions of the microalgae and the impact exerted by the main variable that governs the process (light intensity). For this purpose, the evolution of oxygen concentration in a consortium developed during domestic wastewater treatment was studied and modeled. The analysis revealed important aspects of the symbiosis that is generated between both types of microorganisms: although bacterial oxygen consumption was limited to a few hours after the addition of wastewater, the microalgae not only act as oxygen producers, but photorespiration events and endogenous respiration processes were detected throughout the continuous culture when treating wastewater.
The Biotechnological Processes Unit of Fundación IMDEA Energía recently published an article * in which the oxygen consumed by the microalgae itself during the treatment of wastewater is quantified, using a mathematical model applied to experimental data obtained in the laboratory.
* Barreiro-Vescovo, S., González-Fernández, C., Ballesteros, M., de Godos, I. Activity determination of an algal-bacterial consortium developed during wastewater treatment based on oxygen evolution. Journal of Water Process Engineering 36 (2020) 101278 https://doi.org/10.1016/j.jwpe.2020.101278
More information: Cristina Gonzalez-Fernandez, Senior Researcher, Biotechnology Processes Unit, firstname.lastname@example.org