title: Engineering factors affecting the granulation of sludge in the UASB reactor.
abstract: The influence of inoculum sludge involving different microbial populations, different modes of stream flow and different flow rates in a bioreactor on the granulation of sludge was studied. In the granulation process there were four periods: formation of microbial floccus, formation of subcore, growth of subcore, and maturity of granules. The production of microfloccus could be attributed to acid-forming bacteria. The hydrodynamic momentum transfer caused by moving phases and the hydraulic shear effect are the crucial factors affecting the formation of the subcore. For this a new concept-the lowest limited flow rate-is proposed, i.e., the lowest flow rate to form an expanded sludge bed. A sufficient feed rate (higher than the lowest flow rate), an appropriate sludge load, and an equal distribution of feed, as well as a suitable alkalinity in the medium are the essential factors for the scaling-up and process-control of the UASB reactor.
authors.affiliation: Fuzhou University, Department of Biotechnology, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.forename: C
authors.initials: C
authors.lastname: Meng
authors.forename: X
authors.initials: X
authors.lastname: Shi
authors.forename: H
authors.initials: H
authors.lastname: Qiu
authors.forename: L
authors.initials: L
authors.lastname: Wu
authors.forename: J
authors.initials: J
authors.lastname: Chen
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D001709:Biotechnology; D017019:Methanosarcinaceae / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*
chemical_list: D012722:Sewage