This study was aimed to investigate the organic removal efficiency and microbial population dynamics in activated sludge with pressurized aeration. The activated sludge was fed with synthetic wastewater composed of simple carbon source to avoid the effect of complex components on microbial communities. The pressurized acclimation process was conducted in a bench-scale sequencing batch reactor (SBR) under 0.3 MPa gage pressure. Another SBR was running in atmospheric environment as a control reactor, with the same operation parameters except for the pressure. Bacterial diversity was investigated by Illumina sequencing technology. The results showed that the total organic carbon removal efficiency of the pressurized reactor was significantly higher, while the mixed liquor suspended solids concentrations were much lower than those of the control reactor. Moderate pressure of 0.3 MPa had little effect on Alpha-diversity of bacterial communities due to the similar running conditions, e.g., feed water, SRT and the cyclic change of DO concentrations. Although the relative percentage of the bacterial community changed among samples, there was no major change of predominant bacterial populations between the pressurized group and the control group. Pressurized aeration would have a far-reaching impact on microbial community in activated sludge when treating wastewaters being unfavorable to the dissolution of oxygen.
- activated sludge
- bacterial community diversity
- population dynamics
- pressurized aeration
- sequencing batch reactor
- First received 24 October 2016.
- Accepted in revised form 22 February 2017.
- © IWA Publishing 2017