Influence of the duration of feeding phase on the genotypic structure of bacterial communities in two sequencing batch reactors treating reject water by partial nitritation and anammox

Microbial community and physiochemical processes were monitored by means of denaturing gradient gel electrophoresis (PCR-DGGE) in two sequencing batch reactors (SBRs) running for partial nitritation-anammox and differing in the feeding phase durations (6 h 40 min for SBR1 and 40 min for SBR2). Both SBRs were treated with reject water with a high ammonia concentration (>600 mg for over 370 days. The aim of the experiment was to present the influence of this parameter on total bacterial and anammox bacterial community structure. Molecular analysis revealed that a drastic decrease in influent ammonia concentration to the studied communities caused a change of genotypic structure in their composition. The difference in the reactors working scheme can be the reason for divergence in the community structure though having no drastic influence on its performance and biodiversity level. Feeding time has stronger influence on the genotypic composition of the total bacterial community than on anammox biocenosis.