Comparison of nitrification performance and microbial community between submerged membrane bioreactor and conventional activated sludge system

• Published in: Water science and technology Vol. 51; no. 6-7; pp. 193 - 200
• Main Authors: Li, H, Yang, M, Zhang, Y, Liu, X, Gao, M, Kamagata, Y
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01-01-2005
• Subjects: Activated sludge; Ammonia; Ammonia - metabolism; Analytical methods; Bacteria; Bacteria - growth & development; Biopolymers - metabolism; Bioreactors; Communities; DNA; Electron microscopy; Extracellular; Gel electrophoresis; Gels; Heterotrophic bacteria; Inorganic Chemicals - metabolism; Inorganic wastes; Membranes, Artificial; Microorganisms; Microscopy, Electron, Scanning; Nitrification; Nitrites - chemistry; Nitrites - metabolism; Nucleotide sequence; Oxidation; PCR; Polymerase chain reaction; Prolongation; RNA, Ribosomal, 16S - genetics; rRNA 16S; Scanning electron microscopy; Sewage - microbiology; Sludge; Time Factors; Wastewater; Wastewater treatment; Water Microbiology; Water Pollutants, Chemical - metabolism; Water treatment plants
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2005.0638

A submerged membrane bioreactor (SMBR) and a conventional activated sludge system (CAS) were compared in parallel over a period of more than 260 days on treating synthetic ammonia-bearing inorganic wastewater without sludge purge under decreased hydraulic retention times (HRTs). Conversion of NH4(+)-N to NO3(-)-N was achieved with an efficiency of over 98% at an HRT > or = 10 h in the SMBR, while similar performance was obtained at an HRT > or = 20 h in the CAS. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR) amplified 16S rDNA was used to monitor variations of community structures in the two systems. With the prolongation of operation, the number of DGGE bands in the SMBR gradually increased from the initial 11 bands to the final 22 bands, whereas that in the CAS varied in a range between 13 and 183 Sequence analysis indicates that Nitrosomonas sp. and Nitrospira sp. were the dominating nitrification species responsible for ammonia and nitrite oxidation, respectively. Heterotrophic bacteria like Pseudomonas sp. and Flavobacteria sp. existed in both of the systems although only inorganic wastewater was fed. Substantive accumulation of extracellular polymeric substances (EPS) in the SMBR was confirmed by scanning electron microscopy and EPS analysis.