title: Detailed spatio-temporal solids concentration profiling during batch settling of activated sludge using a radiotracer.
abstract: In building and tuning good settling models for secondary clarifiers of wastewater treatment plants, there is a need for measured continuous solids concentration profiles during batch settling. Conventional measuring techniques have difficulties in recording this kind of data, either because they are invasive, or because of the low solids concentration and/or solids density of activated sludge. This paper investigates a novel non-invasive measurement technique borrowed from nuclear medicine, using a solids radiotracer and gamma cameras, to obtain solids concentration profiles during the batch settling of activated sludge, in a pilot-scale column with a height of 1m. The technique does not disturb the settling process, does not alter the settling characteristics, gives profiles every minute and every few millimeters, and is capable of measuring in a range of 0-25 g/l with high accuracy. Dynamic solids concentration profile measurements were performed for sludges of different wastewater treatment plants, and at different initial concentrations. The results show a quantitative representation of the settling process, and reveal hindered and compression settling.
authors.affiliation: Department of Chemical Engineering and Technical Chemistry, Ghent University, Technologiepark 914, 9052 Zwijnaarde, Belgium. jeriffa.declercq@ugent.be
authors.forename: Jeriffa
authors.initials: J
authors.lastname: De Clercq
authors.forename: Filip
authors.initials: F
authors.lastname: Jacobs
authors.forename: David J
authors.initials: DJ
authors.lastname: Kinnear
authors.forename: Ingmar
authors.initials: I
authors.lastname: Nopens
authors.forename: Rudi A
authors.initials: RA
authors.lastname: Dierckx
authors.forename: Jacques
authors.initials: J
authors.lastname: Defrancq
authors.forename: Peter A
authors.initials: PA
authors.lastname: Vanrolleghem
mesh_terms: D015902:Gamma Cameras; D007553:Isotope Labeling / Q000379:methods*; D008433:Mathematics; D012722:Sewage / Q000737:chemistry*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage