title: Impact of seawater-quality and water treatment procedures on the active bacterial assemblages at two desalination sites.
abstract: Inorganic and organic compounds, particles and microorganisms in intake waters are mainly responsible for fouling of reverse osmosis membranes, which reduces the efficiency of the desalination process. The characterization of seawater quality to better predict its fouling potential remains a challenge for the desalination field and little is known about the seasonal variability of water quality parameters in the coastal waters used to supply desalination plants. In this study, standard water quality methods were combined with flow cytometry and molecular methods (16S rRNA sequencing and fingerprinting) to assess in parallel, the physicochemical properties, the microbial abundance and the active microbial community composition of the intake waters and their associated pretreated waters at two desalination sites from July 2007 to July 2008. The overall assessment of quality parameters revealed that microfiltration followed by slow sand filtration were the most efficient in removing microorganisms than the conventional dual media filtration routinely used in full-scale desalination plants, and that all treatments were inefficient for organic matter reduction. Temporal variation of the environmental parameters such as temperature, turbidity and silt density index only moderately affected the bacterial community structure in raw waters, but that interestingly, water treatment compartments changed the composition and diversity of the metabolically active bacterial populations and thus create distinct ecological post-treatment niches.
authors.affiliation: UPMC Univ Paris 06, UMR 7621, LOMIC, Observatoire Océanologique, F-66651, Banyuls/mer, France. carmem.manes@obs-banyuls.fr
authors.forename: C-L de O
authors.initials: CL
authors.lastname: Manes
authors.forename: C
authors.initials: C
authors.lastname: Barbe
authors.forename: N J
authors.initials: NJ
authors.lastname: West
authors.forename: S
authors.initials: S
authors.lastname: Rapenne
authors.forename: P
authors.initials: P
authors.lastname: Lebaron
mesh_terms: D001419:Bacteria / Q000235:genetics*; D001483:Base Sequence; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D017931:DNA Primers / Q000235:genetics; D005374:Filtration; D005434:Flow Cytometry; D008567:Membranes, Artificial; D008969:Molecular Sequence Data; D009930:Organic Chemicals / Q000032:analysis*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013696:Temperature; D018508:Water Purification / Q000295:instrumentation / Q000379:methods / Q000592:standards*
chemical_list: D017931:DNA Primers; D008567:Membranes, Artificial; D009930:Organic Chemicals; D012336:RNA, Ribosomal, 16S