title: Dielectric monitoring and respirometric activity of a high cell density activated sludge.
abstract: A novel method was developed to assess the viability of activated sludge present in a biological wastewater treatment process and signify its distinction from respirometric activity. The respirometric activity and viability of activated sludge at high cell density, such as typically encountered in membrane bioreactors, were investigated in batch and fed-batch systems. The method for measuring the viability of activated sludge was based on the sludge permittivity monitored online by a capacitive sensor. Results from permittivity measurement were compared with usual biological activity measurement through oxygen uptake rate determination. The similar downward trend was observed for both measurements. The respirometric activity and permittivity, respectively, reduced to 50% and 68% of initial value in the fed-batch system and 18% and 27% of initial value for the batch system which was due to quantitative and qualitative changes in the microbial culture in the activated sludge. The novel method allows to made distinction between viable versus dead and inactive versus active microbial cells in the activated sludge system and can be used for better and more efficient control of the biological processes.
authors.affiliation: School of Chemical Engineering, College of Engineering, University of Tehran, Avenue Enghelab, P.O. Box 11155-4563, Tehran, Iran.
authors.forename: Farshid
authors.initials: F
authors.lastname: Pajoum-Shariati
authors.affiliation: School of Chemical Engineering, College of Engineering, University of Tehran, Avenue Enghelab, P.O. Box 11155-4563, Tehran, Iran.
authors.forename: Mohammad-Hossein
authors.initials: MH
authors.lastname: Sarrafzadeh
authors.affiliation: School of Chemical Engineering, College of Engineering, University of Tehran, Avenue Enghelab, P.O. Box 11155-4563, Tehran, Iran.
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Mehrnia
authors.affiliation: lEM, Université Montpellier 2, F-34095, Montpellier, France.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Sarzana
authors.affiliation: C UMR IA TE, Université Montpellier 2, Place Eugine Bataillon-CC023, 34095, Montpellier Cedex 05, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Ghommidh
authors.affiliation: lEM, Université Montpellier 2, F-34095, Montpellier, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Grasmick
authors.affiliation: lEM, Université Montpellier 2, F-34095, Montpellier, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Heran
mesh_terms: D001420:Bacteria, Aerobic / Q000502:physiology*; D061249:Batch Cell Culture Techniques / Q000295:instrumentation*; D019149:Bioreactors / Q000382:microbiology*; D002452:Cell Count; D058266:Dielectric Spectroscopy / Q000379:methods*; D004867:Equipment Design; D008422:Materials Testing / Q000295:instrumentation; D012722:Sewage / Q000032:analysis* / Q000382:microbiology*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D012722:Sewage