Community Structure and Quantification of Nitrifying Bacteria in Integrated Fixed Film Activated Sludge System Treating Industrial Wastewater

Abstract

Abstract-To reveal the community structure and abundance of ammonia-oxidizing bacterial (AOB) and nitrite-oxidizing bacterial (NOB) in integrated fixed film activated sludge process (IFAS) treating industrial wastewater, the molecular biological techniques of polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), cloning and sequencing and realtime quantitative PCR were applied. DGGE results showed that in the process of the experiment, the dominant species of suspended sludge and biofilm were different and that some kinds of populations had been highly preponderance consistently. Additionally, variation in influents had no significant effect on the distribution of the AOB and NOB communities. Sequencing analysis of screened clones revealed Nitrosospira sp. was the particular AOB population in suspended sludge, and some members of Nitrosomonas sp. are helpful to keep the biomass remained in the bio-carrier surface. Real-time PCR indicated that the proportion of the AOB and NOB in total amount of bacteria increased significantly after the domestication period. The AOB and NOB population in the suspended sludge were even higher than the content of the biofilm.