The temporal dynamics of active microbial populations and associated bioreactor performance within time-managed treatment processes, such as sequencing batch membrane bioreactor (SBMBR) systems, remain unknown. To address this issue, we paired operational performance of organic micropollutant (such as pharmaceutical residues or personal care products) and nutrient removal with high-throughput Illumina MiSeq sequencing of expressed small subunit (SSU) rRNA genes, as a proxy for microbial activity, in a demonstration-scale SBMBR. The experiment was replicated temporally and at two sludge retention times (SRT), 20 days and 5 days, with anaerobic-oxic-anoxic periods typical of enhanced biological phosphorus removal (EBPR) processes. Our results show two compositionally distinct microbial communities at high and low SRTs. Orders Burkholderiales (~25%) and Sphingomonadales (~30%), within the phyla Betaproteobacteria and Bacteroidetes, respectively dominated the low SRT DNA sequence libraries. At the high SRT treatment, however, the six most abundant active populations within our cDNA libraries were also within bacterial phyla Bacteroidetes and Betaproteobacteria as well as Deltaproteobacterial order Myxococcales (ranked 2nd in abundance)  . Each population of organisms had distinct temporal abundance profiles corresponding to anaerobic-oxic-anoxic periods within the treatment cycle. Micropollutant removal from the liquid phase was observed only during oxic periods. These results hint to aerobic-dependent removal of micropollutants by populations of microorganisms that are active during oxic periods of the EBPR process.

Diversity, dynamics, and function of active microbial populations transforming organic micropolluants in activated sludge treatment systems

248th National Meeting (2014)

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