title: Bioaugmentation and enhanced formation of microbial granules used in aerobic wastewater treatment.
abstract: Microbial aggregates of an aerobic granular sludge can be used for the treatment of industrial or municipal wastewater, but their formation from a microbial activated sludge requires several weeks. Therefore, the aim of this research was the selection of microbial cultures to shorten the granule-forming period from several weeks to a few days. An enrichment culture with the ability to accelerate granulation was obtained by repeating the selection and batch cultivation of fast-settling microbial aggregates isolated from the aerobic granular sludge. Bacterial cultures of Klebsiella pneumoniae strain B and Pseudomonas veronii strain F, with self-aggregation indexes of 65 and 51%, respectively, and a coaggregation index of 58%, were isolated from the enrichment culture. A mixture of these strains with the activated sludge was used as an inoculum in an experimental sequencing batch reactor to start up an aerobic granulation process. Aerobic granules with a mean diameter of 446+/-76 microm were formed in an experiment after 8 days of cultivation, but microbial granules were absent in controls. Considering biosafety issues, K. pneumoniae strain B was excluded from further studies, but P. veronii strain F was selected for larger-scale testing.
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore. cvivanov@ntu.edu.sg
authors.forename: Volodymyr
authors.initials: V
authors.lastname: Ivanov
authors.forename: Xiao-Hui
authors.initials: XH
authors.lastname: Wang
authors.forename: Stephen Tiong-Lee
authors.initials: ST
authors.lastname: Tay
authors.forename: Joo-Hwa
authors.initials: JH
authors.lastname: Tay
mesh_terms: D000332:Aerobiosis; D001422:Bacterial Adhesion; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods; D003470:Culture Media; D007711:Klebsiella pneumoniae / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D010316:Particle Size; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D003470:Culture Media; D012722:Sewage