Assessing the effects of solids residence time and volatile fatty acid augmentation on biological phosphorus removal...

The purpose of the research presented herein was to evaluate the effects of solids residence time (SRT) and organic acid augmentation on biological phosphorus removal (BPR), with a focus on how these operational variables affect key metabolisms and the distribution of the microbial population. Using laboratory-scale sequencing batch reactors seeded with a mixed microbial consortium and fed real wastewater, we observed that longer SRTs can improve BPR performance; organic acid augmentation can stabilize BPR, but it is not necessary for process success; and higher volatile suspended solids concentrations correlate with improved phosphorus removal. The results also suggest that organic acids may not be critical in driving anaerobic phosphorus release, but in driving aerobic growth. Finally, given an observed population similarity across all tested bioreactors, BPR variability appears to be less influenced by the presence of specific microbes and more affected by the induction of critical metabolisms.