Performance of aerobic granular sludge in a sequencing batch bioreactor exposed to ofloxacin, norfloxacin and ciprofloxacin

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Amorim, CL (Author) Other; Maia, AS (Author) Other; Mesquita, RBR (Author) Other; Rangel, AOSS (Author) Other; van Loosdrecht, MCM (Author) Other; Tiritan M.E. (Author) FFUP; Castro, PML (Author) Other

Journal

Title: Water Research

Vol. 50

Pages: 101-113

ISSN: 0043-1354

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 193 Citations

Scopus - 215 Citations

Other information

Authenticus ID: P-008-K1N

DOI: 10.1016/j.watres.2013.10.043

Abstract (EN): A granular sludge sequencing batch reactor (SBR) was operated for 340 days for treating a synthetic wastewater containing fluoroquinolones (FQs), namely ofloxacin, norfloxacin and ciprofloxacin. The SBR was intermittently fed with FQs, at concentrations of 9 and 32 mu M. No evidence of FQ biodegradation was observed but the pharmaceutical compounds adsorbed to the aerobic granular sludge, being gradually released into the medium in successive cycles after stopping the FQ feeding. Overall COD removal was not affected during the shock loadings. Activity of ammonia oxidizing bacteria and nitrite oxidizing bacteria did not seem to be inhibited by the presence of FQs (maximum of 0.03 and 0.01 mM for ammonium and nitrite in the effluent, respectively). However, during the FQs feeding, nitrate accumulation up to 1.7 mM was observed at the effluent suggesting that denitrification was inhibited. The activity of phosphate accumulating organisms was affected, as indicated by the decrease of P removal capacity during the aerobic phase. Exposure to the FQs also promoted disintegration of the granules leading to an increase of the effluent solid content, nevertheless the solid content at the bioreactor effluent returned to normal levels within ca. 1 month after removing the FQs in the feed allowing recovery of the bedvolume. Denaturing gradient gel electrophoresis revealed a dynamic bacterial community with gradual changes due to FQs exposure. Bacterial isolates retrieved from the granules predominantly belonged to alpha- and gamma-branch of the Proteobacteria phylum.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13