title: Effect of chemical and biological surfactants on activated sludge of MBR system: microscopic analysis and foam test.
abstract: A bench-scale MBR unit was operated, under stressing condition, with the aim of stimulating the onset of foaming in the activated sludge. Possible synergies between synthetic surfactants in the wastewater and biological surfactants (Extra-Cellular Polymeric Substances, EPSs) were investigated by changing C/N ratio. The growth of filamentous bacteria was also discussed. The MBR unit provided satisfactory overall carbon removal overall efficiencies: in particular, synthetic surfactants were removed with efficiency higher than 90% and 95% for non-ionic and ionic surfactants, respectively. Lab investigation suggested also the importance to reduce synthetic surfactants presence entering into mixed liquor: otherwise, their presence can significantly worsen the natural foaming caused by biological surfactants (EPSs) produced by bacteria. Finally, a new analytic method based on "ink test" has been proposed as a useful tool to achieve a valuation of EPSs bound fraction.
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali - Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Capodici
authors.affiliation: Facoltà di Ingegneria e Architettura - Università di Enna "Kore", Cittadella Universitaria, 94100 Enna, Italy. Electronic address: gaetano.dibella@unikore.it.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Di Bella
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali - Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Nicosia
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali - Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Torregrossa
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D001704:Biopolymers / Q000737:chemistry; D019149:Bioreactors; D008567:Membranes, Artificial; D008853:Microscopy; D012722:Sewage / Q000737:chemistry*; D013501:Surface-Active Agents / Q000494:pharmacology*; D014783:Viscosity
chemical_list: D001704:Biopolymers; D008567:Membranes, Artificial; D012722:Sewage; D013501:Surface-Active Agents
keywords: Foam test; Foaming; Ink test; MBR; Surfactant