Send to

Choose Destination
Appl Microbiol Biotechnol. 2012 Nov;96(3):815-27. doi: 10.1007/s00253-011-3838-6. Epub 2012 Jan 19.

Backwash intensity and frequency impact the microbial community structure and function in a fixed-bed biofilm reactor.

Author information

Department of Civil Engineering, University of Nebraska-Lincoln, 844 N. 16th St., N117 SEC Link, Lincoln, NE 68588-6105, USA.


Linkages among bioreactor operation and performance and microbial community structure were investigated for a fixed-bed biofilm system designed to remove perchlorate from drinking water. Perchlorate removal was monitored to evaluate reactor performance during and after the frequency and intensity of the backwash procedure were changed, while the microbial community structure was studied using clone libraries and quantitative PCR targeting the 16S rRNA gene. When backwash frequency was increased from once per month to once per day, perchlorate removal initially deteriorated and then recovered, and the relative abundance of perchlorate-reducing bacteria (PRB) initially increased and then decreased. This apparent discrepancy suggested that bacterial populations other than PRB played an indirect role in perchlorate removal, likely by consuming dissolved oxygen, a competing electron acceptor. When backwash intensity was increased, the reactor gradually lost its ability to remove perchlorate, and concurrently the relative abundance of PRB decreased. The results indicated that changes in reactor operation had a profound impact on reactor performance through altering the microbial community structure. Backwashing is an important yet poorly characterized procedure when operating fixed-bed biofilm reactors. Compared to backwash intensity, changes in backwash frequency exerted less disturbance on the microbial community in the current study. If this finding can be confirmed in future work, backwash frequency may serve as the primary parameter when optimizing backwash procedures.

[Indexed for MEDLINE]

Publication type, MeSH terms, Substances, Secondary source ID

Publication type

MeSH terms


Secondary source ID

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center