title: Effect of temperature on selenium removal from wastewater by UASB reactors.
abstract: The effect of temperature on selenium (Se) removal by upflow anaerobic sludge blanket (UASB) reactors treating selenate and nitrate containing wastewater was investigated by comparing the performance of a thermophilic (55 °C) versus a mesophilic (30 °C) UASB reactor. When only selenate (50 μM) was fed to the UASB reactors (pH 7.3; hydraulic retention time 8 h) with excess electron donor (lactate at 1.38 mM corresponding to an organic loading rate of 0.5 g COD L(-1) d(-1)), the thermophilic UASB reactor achieved a higher total Se removal efficiency (94.4 ± 2.4%) than the mesophilic UASB reactor (82.0 ± 3.8%). When 5000 μM nitrate was further added to the influent, total Se removal was again better under thermophilic (70.1 ± 6.6%) when compared to mesophilic (43.6 ± 8.8%) conditions. The higher total effluent Se concentration in the mesophilic UASB reactor was due to the higher concentrations of biogenic elemental Se nanoparticles (BioSeNPs). The shape of the BioSeNPs observed in both UASB reactors was different: nanospheres and nanorods, respectively, in the mesophilic and thermophilic UASB reactors. Microbial community analysis showed the presence of selenate respirers as well as denitrifying microorganisms.
authors.affiliation: UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands; DICAAR, Dept. of Civil-Environmental Engineering and Architecture, Piazza d'Armi, 09123, Cagliari, Italy; Department of Chemistry and Bioengineering, Tampere University of Technology, Korkeakoulunkatu 10, FI-33720, Tampere, Finland.
authors.forename: Paolo
authors.initials: P
authors.lastname: Dessì
authors.affiliation: UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands; Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 5, Boulevard Descartes - Champs sur Marne, 77454, Marne-la-Vallée, France; Department of Chemistry and Bioengineering, Tampere University of Technology, Korkeakoulunkatu 10, FI-33720, Tampere, Finland. Electronic address: rohanjain.iitd@gmail.com.
authors.forename: Rohan
authors.initials: R
authors.lastname: Jain
authors.affiliation: Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, Hauz-Khas, 110016, New Delhi, India.
authors.forename: Satyendra
authors.initials: S
authors.lastname: Singh
authors.affiliation: Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 5, Boulevard Descartes - Champs sur Marne, 77454, Marne-la-Vallée, France; Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC). Sorbonne Universités - UPMC Univ Paris 06, UMR CNRS, 7590, Muséum National d'Histoire Naturelle, IRD UMR 206, Paris, France.
authors.forename: Marina
authors.initials: M
authors.lastname: Seder-Colomina
authors.affiliation: Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 5, Boulevard Descartes - Champs sur Marne, 77454, Marne-la-Vallée, France.
authors.forename: Eric D
authors.initials: ED
authors.lastname: van Hullebusch
authors.affiliation: UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands.
authors.forename: Eldon R
authors.initials: ER
authors.lastname: Rene
authors.affiliation: Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, Hauz-Khas, 110016, New Delhi, India.
authors.forename: Shaikh Ziauddin
authors.initials: SZ
authors.lastname: Ahammad
authors.affiliation: DICAAR, Dept. of Civil-Environmental Engineering and Architecture, Piazza d'Armi, 09123, Cagliari, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Carucci
authors.affiliation: UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands; Department of Chemistry and Bioengineering, Tampere University of Technology, Korkeakoulunkatu 10, FI-33720, Tampere, Finland.
authors.forename: Piet N L
authors.initials: PNL
authors.lastname: Lens
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors / Q000382:microbiology; D009566:Nitrates / Q000737:chemistry; D064586:Selenic Acid / Q000737:chemistry; D012643:Selenium / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry; D013696:Temperature; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D009566:Nitrates; D064586:Selenic Acid; D012643:Selenium; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Nitrate; Selenate; Selenium nanoparticles; Thermophilic; UASB