RESPIROMETRIC ASSESSMENT OF BACTERIAL KINETICS IN ALGAE-BACTERIA AND ACTIVATED SLUDGE PROCESSES

Abstract

Algae-bacteria consortia can be successfully exploited for effective wastewater treatment, based on the algal photosynthetic oxygen production, which allows reducing energy requirements for oxygenation. Kinetic models and parameters for bacterial populations grown in the conventional activated sludge process are well known but their effectiveness in describing bacterial kinetics in algae-bacteria consortia have not been yet validated. In this work, a respirometric procedure was applied to estimate bacterial kinetics at different conditions of temperature, pH, dissolved oxygen and substrates concentrations in activated sludge and algae-bacteria consortia, highlighting important differences. Results showed that bacterial activities were influenced by process operation and environmental conditions in the two systems. Bacteria in algae-bacteria consortia were adapted to a wider range of conditions compared to activated sludge bacteria, suggesting that calibrating algae-bacteria kinetic models is essential for an effective modelling, and respirometry was proven to be a powerful tool to this purpose.