Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1080/09593330.2012.722758
Title (Primary) Long-term starvation and subsequent recovery of nitrifiers in aerated submerged fixed-bed biofilm reactors
Author Elawwad, A.; Sandner, H.; Kappelmeyer, U. ORCID logo ; Koeser, H.
Source Titel Environmental Technology
Year 2013
Department UBT
Volume 34
Issue 8
Page From 945
Page To 959
Language englisch
Keywords biofilm; nitrification; starvation; recovery; TRFLP
UFZ wide themes ru3
Abstract The effectiveness of three operational strategies for maintaining nitrifiers in bench-scale, aerated, submerged fixed-bed biofilm reactors (SFBBRs) during long-term starvation at 20°C were evaluated. The operational strategies were characterized by the resulting oxidation-reduction potential (ORP) in the SFBBRs. The activity rates of the nitrifiers were measured and the activity decay was expressed by half-life times. It was found that anoxic and alternating anoxic/aerobic conditions were the best ways to preserve ammonia-oxidizing bacteria (AOB) during long starvation periods and resulted in half-life times of up to 34 and 28 days, respectively. Extended anaerobic conditions caused the half-life for AOB to decrease to 21 days. In comparison, the activity decay of nitrite-oxidizing bacteria (NOB) tended to be slightly faster. The activity of AOB biofilms that were kept for 97 days under anoxic conditions could be completely recovered in less than one week, while over 4 weeks was needed for AOB kept under anaerobic conditions. NOB were more sensitive to starvation and required longer recovery periods than AOB. For complete recovery, NOB needed approximately 7 weeks, regardless of the starvation conditions applied. Using the fluorescence in situ hybridization (FISH) technique, Nitrospira was detected as the dominant NOB genus. Among the AOB, the terminal restriction fragment length polymorphism (TRFLP) technique showed that during starvation and recovery periods, the relative frequency of species shifted to Nitrosomonas europaea/eutropha, regardless of the starvation condition. The consequences of these findings for the operation of SFBBRs under low-load and starvation conditions are discussed.

Persistent UFZ Identifier
Elawwad, A., Sandner, H., Kappelmeyer, U., Koeser, H. (2013):
Long-term starvation and subsequent recovery of nitrifiers in aerated submerged fixed-bed biofilm reactors
Environ.Technol. 34 (8), 945 - 959 10.1080/09593330.2012.722758