1 research outputs found
A novel photo-respirometry method to characterize consortia in microalgae-related wastewater treatment processes.
In this paper, a new photo-respirometry method for determining the rates of the main metabolic processes of
microalgae-bacteria consortia in microalgae-based wastewater treatment processes has been developed and
tested. The proposed protocol consists on applying dark and light periods to a microalgae-bacteria consortium in
the presence of different substrates and measuring the rate of oxygen production. This allows determining the
activity of microalgae, heterotrophic bacteria and nitrifying bacteria separately.
The method has been optimized in terms of the operation strategy, including the starvation period required,
the biomass concentration and the irradiance during the measurements. Results show that a starvation period of
one to three days is necessary depending on the nutrient concentration. The optimal experimental conditions
determined were a biomass concentration of 0.5 g/L and an irradiance of 200 μmol photons/m2·s. Furthermore,
microalgae-bacteria samples from seven photobioreactors (indoor and outdoor) with different nutrient sources
have been evaluated applying the methodology proposed. Regardless of the wastewater type, the microalgae
activity is the main metabolic process, with heterotrophic activity increasing along with the chemical oxygen
demand (COD) in the wastewater. Nitrifying activity was only observed when high ammonium concentrations
were present. The developed method is a powerful tool to adequately manage and operate wastewater treatment
processes using microalgae/bacteria consortia, providing valuable information to model wastewater treatment
systems with microalgae and determine kinetic parameters