Biodegradation and metabolism of Tetrabromobisphenol A (TBBPA) in the bioaugmented activated sludge batch bioreactor system by heterotrophic and nitrifying bacteria

Tetrabromobisphenol A [2,4´-isopropylidenebis(2,6-dibromophenol)] has been identified in wastewater samples collected from the Guelph municipal wastewater treatment plant (GWWTP). In order to assess the kinetics and metabolic mechanisms of the dissolved TBBPA, bench scale experiments were completed with batch bioreactors. The biodegradation test was conducted by taking aerobic sludge from the conventional activated sludge reactor (CAS) and membrane bioreactor (MBR), and bioaugmenting both reactors with soil based strains of Bacillus brevis and Bacillus pumilus. This novel biodegradation process showed that the CAS bioreactor had a biodegradation rate of 0.127 d-1, while the sludge from the MBR had biodegradation rate of 0.171 d-1. This is the first reported aerobic biodegradation of TBBPA by heterotrophic and nitrifying bacteria in activated sludge bioreactor system. A tentative biotransformation metabolic scheme for TBBPA biodegradation and metabolite formation has been proposed as well.