Research Information System
Desalination and Water Treatment, vol.56, no.4, pp.862-874, 2015 (SCI-Expanded)
The study investigated the effect of sludge age on substrate utilization kinetics, soluble microbial product generation, and composition of the microbial community sustained in a superfast submerged membrane bioreactor (SSMBR). For this purpose, a laboratory-scale membrane bioreactors (MBR) unit was operated at steady state, with three different sludge ages in extremely low range of 0.5–2.0 d, and a hydraulic retention time of 8.0 h. Substrate feeding was adjusted to 220–250 mg COD/L and involved a synthetic mixture representing the readily biodegradable COD fraction in domestic sewage. The MBR operation at sludge age of 1.0 d was duplicated with acetate feeding as the sole organic carbon source. Under different operating conditions, SSMBR was able to secure complete removal of available soluble/readily biodegradable substrate, with a residual microbial product level as low as 20–30 mg COD/L, partly retained and accumulated in reactor volume. Phylogenic analysis based on polymerase chain reactions-denaturing gradient gel electrophoresis analysis indicated that selected sludge ages affected the composition of microbial community. Lower sludge ages selected a community characterized by faster rates for microbial growth. Results confirmed the existence of a functional relationship between variable process kinetics and changes in the microbial community structure, even for slight variations that can be inflicted on the culture history while operating superfast MBR systems.