Microbial and physicochemical characteristics of compact anaerobic ammonium-oxidizing granules in an upflow anaerobic sludge blanket reactor.
Anaerobic ammonium oxidation (anammox) is a promising new process to treat high-strength nitrogenous wastewater. Due to the low growth rate of anaerobic ammonium-oxidizing bacteria, efficient biomass retention is essential for reactor operation. Therefore, we studied the settling ability and community composition of the anaerobic ammonium-oxidizing granules, which were cultivated in an upflow anaerobic sludge blanket (UASB) reactor seeded with aerobic granules. With this seed, the start-up period was less than 160 days at a NH(4)(+)-N removal efficiency of 94% and a loading rate of 0.064 kg N per kg volatile suspended solids per day. The formed granules were bright red and had a high settling velocity (41 to 79 m h(-1)). Cells and extracellular polymeric substances were evenly distributed over the anaerobic ammonium-oxidizing granules. The high percentage of anaerobic ammonium-oxidizing bacteria in the granules could be visualized by fluorescent in situ hybridization and electron microscopy. The copy numbers of 16S rRNA genes of anaerobic ammonium-oxidizing bacteria in the granules were determined to be 4.6 x 10(8) copies ml(-1). The results of this study could be used for a better design, shorter start-up time, and more stable operation of anammox systems for the treatment of nitrogen-rich wastewaters.
Ni
Bing-Jie
BJ
Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
Hu
Bao-Lan
BL
Fang
Fang
F
Xie
Wen-Ming
WM
Kartal
Boran
B
Liu
Xian-Wei
XW
Sheng
Guo-Ping
GP
Jetten
Mike
M
Zheng
Ping
P
Yu
Han-Qing
HQ
D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D015169:Colony Count, Microbial / Q000379:methods; D017404:In Situ Hybridization, Fluorescence; D010084:Oxidation-Reduction; D052638:Particulate Matter; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D018508:Water Purification
D052638:Particulate Matter; D000644:Quaternary Ammonium Compounds; D012336:RNA, Ribosomal, 16S; D012722:Sewage