title: Start-up of a granular sludge sequencing batch reactor for the treatment of 2,4-dichlorophenol-contaminated wastewater.
abstract: In this study, a granular sludge sequencing batch reactor (GSBR) was started-up for the biological aerobic treatment of wastewater containing highly toxic 2,4-dichlorophenol (2,4-DCP), in presence of readily biodegradable sodium acetate (NaAc) as the growth substrate. Different influent concentrations of NaAc (420-800 mg/L) and 2,4-DCP (0-20 mg/L), as well as different operating conditions (i.e. cycle length), were tested in order to determine the optimal strategy for successful GSBR start-up: stable granulation and complete 2,4-DCP removal were achieved only when high NaAc influent concentration and volumetric organic loading rates (800 mg/L and 1.9 kgCOD/(m(3)·d), respectively), prolonged reaction phase (cycle time of 4 hours) and gradual increase of 2,4-DCP concentration in the influent were applied, thus providing useful information for process optimization in view of future scale-up. Granules were initially colonized by fungi which progressively disappeared during the start-up process, and complete 2,4-DCP removal was mostly due to bacterial activity, in particular Betaproteobacteria, as shown by fluorescence in situ hybridization (FISH).
authors.affiliation: Institute of Environmental Geology and Geoengineering (IGAG-CNR), Piazza d'Armi, 09123 Cagliari, Italy E-mail: smilia@unica.it.
authors.forename: S
authors.initials: S
authors.lastname: Milia
authors.forename: R
authors.initials: R
authors.lastname: Porcu
authors.forename: S
authors.initials: S
authors.lastname: Rossetti
authors.forename: A
authors.initials: A
authors.lastname: Carucci
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors; D002733:Chlorophenols / Q000378:metabolism*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D002733:Chlorophenols; C004762:2,4-dichlorophenol