Respirometry for the assessment of biomass activity in Membrane Bioreactors

The aim of the study was to use respirometric techniques for the characterization of biomass biokinetic behaviour in several MBR pilot plants characterized by different configurations, different operational conditions and fed with wastewater of different features (domestic/industrial). Four different MBR pilot plants were investigated: i) a sequencing batch MBR (SB-MBR) subjected to a gradual salinity increase; ii) a pre-denitrification MBR system for the treatment of saline wastewater contaminated by hydrocarbons; iii) a University of Cape Town MBR system (UCT-MBR) for the treatment of domestic wastewater subjected to a carbon-to-nitrogen (C/N) ratio variation; iiii) a UCT-IFAS-MBR for the treatment of domestic wastewater characterized by the variation of several operational parameters. The achieved results highlighted the significant influence that plant configuration and operational conditions might exert on biomass respiratory activity, referring to both autotrophic and heterotrophic bacterial species.