title: Nitrifying-denitrifying filters and UV-C disinfection reactor: a combined system for wastewater treatment.
abstract: Biological treatment systems use the natural processes of ubiquitous organisms to remove pollutants and improve the water quality before discharge to the environment. In this paper, the nitrification/denitrification reactor allowed a reduction in organic load, but offered a weak efficiency in nitrate reduction. However, the additions of the activated sludge in the reactor improve this efficiency. A decrease of [Formula: see text] values from 13.3 to 8 mg/l was noted. Nevertheless, sludge inoculation led to a net increase of the number of pathogenic bacteria. For this reason, a UV-C pilot reactor was installed at the exit of the biological nitrification-denitrification device. Thus, a fluence of 50 mJ.cm-2was sufficient to achieve values of 20 MPN/100 ml for fecal coliform and 6 MPN/100 ml for fecal streptococci, conforms to Tunisian Standards of Rejection. On the other hand, the DGGE approach has allowed a direct assessment of the bacterial community changes upon the treated wastewater.
authors.affiliation: a Wastewater Treatment Laboratory, Water Research and Technologies , Soliman , Tunisia.
authors.forename: Asma
authors.initials: A
authors.lastname: Ben Rajeb
authors.affiliation: a Wastewater Treatment Laboratory, Water Research and Technologies , Soliman , Tunisia.
authors.forename: Inès
authors.initials: I
authors.lastname: Mehri
authors.affiliation: a Wastewater Treatment Laboratory, Water Research and Technologies , Soliman , Tunisia.
authors.forename: Houda
authors.initials: H
authors.lastname: Nasr
authors.affiliation: b Microorganisms and Active Biomolecules Laboratory, Faculty of Sciences , University of Tunis El Manar , Tunis , Tunisia.
authors.forename: Afef
authors.initials: A
authors.lastname: Najjari
authors.affiliation: a Wastewater Treatment Laboratory, Water Research and Technologies , Soliman , Tunisia.
authors.forename: Neila
authors.initials: N
authors.lastname: Saidi
authors.affiliation: a Wastewater Treatment Laboratory, Water Research and Technologies , Soliman , Tunisia.
authors.forename: Abdennaceur
authors.initials: A
authors.lastname: Hassen
mesh_terms: D001419:Bacteria / Q000145:classification; D058645:Denaturing Gradient Gel Electrophoresis; D058440:Denitrification; D004203:Disinfection; D005374:Filtration; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012722:Sewage / Q000382:microbiology*; D014416:Tunisia; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000382:microbiology*; D060753:Water Quality
chemical_list: D009584:Nitrogen; D012722:Sewage; D062065:Wastewater
keywords: Biological reactor; PCR–DGGE; UV-C reactor; nitrogen removal; pathogen removal