Qualitative analysis of bacterial biocenoses in two sequencing batch reactors treating reject water under different technological conditions

Complete nitrogen removal over nitrite (CANON) was used to treat reject water with ammonia concentrations ranging from 70 to 154mg·L-1. Two experimental sequential batch reactors, SBR_A and SBR_B, differed in the time of the reject water inflow (6h40min vs 40min), process temperature (25 vs 29°C), and the number of aeration periods per day (3 vs 6, respectively). Nitrogen removal efficiency was higher in SBR_B (50-90%) than in SBR_A (40-80%). Analysis of total (PCR-DGGE) and active (RT-PCR-DGGE) bacteria revealed that the biodiversity of the bacterial biocenoses, expressed as the Shannon-Wiener Biodiversity Index, was higher in SBR_B (2.75-3.10) than in SBR_A (1.80-2.75).