title: Macro- and microscopic in-situ observation of gas bubbles and sludge particles in a biogas tower reactor.
abstract: Macroscopic and microscopic in-situ observation of particles and gas bubbles are used to get precise impressions of the hydrodynamical characteristics of a biologically active suspension. Moreover, values of in-situ velocities and particle densities can be gained by using these methods. The suspended anaerobic sludge revealed an extensive fibrous structure ('fur') on its surface. The observed microfibers have a profound influence on the settling/flotation behavior of the particles because they increase the effective particle volume, they may trap gas bubbles and they favor agglomeration. The biomass particles do not appear as single spherical objects but due to its fibrous structure on the outside as strongly interacting mass. The compressibility of the bubbles which are entrapped in the sludge agglomerates results in a pressure-dependent density of the sludge particles.
authors.affiliation: Deutsche Hefewerke GmbH and Co. oHG, Hamburg, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Pietsch
authors.forename: Ralf
authors.initials: R
authors.lastname: Mehrwald
authors.forename: Ralf
authors.initials: R
authors.lastname: Grajetzki
authors.forename: Jan
authors.initials: J
authors.lastname: Sens
authors.forename: Tim
authors.initials: T
authors.lastname: Pakendorf
authors.forename: Reinhard
authors.initials: R
authors.lastname: Ulrich
authors.forename: Jörn
authors.initials: J
authors.lastname: Kumpart
authors.forename: Gerhard
authors.initials: G
authors.lastname: Matz
authors.forename: Herbert
authors.initials: H
authors.lastname: Märkl
mesh_terms: D018533:Biomass; D019149:Bioreactors; D005374:Filtration; D005427:Flocculation; D005740:Gases; D010316:Particle Size; D012037:Refuse Disposal; D012722:Sewage / Q000737:chemistry*; D014872:Water Movements
chemical_list: D005740:Gases; D012722:Sewage