title: Evaluation of the microbiological quality of reclaimed water produced from a lagooning system.
abstract: The use of lagooning as a complementary natural method of treating secondary effluents of wastewater treatment plants has been employed as an affordable and easy means of producing reclaimed water. However, using reclaimed water for some purposes, for example, for food irrigation, presents some risks if the effluents contain microbial pathogens. Classical bacterial indicators that are used to assess faecal contamination in water do not always properly indicate the presence of bacterial or viral pathogens. In the current study, the presence of faecal indicator bacteria (FIB), heterotrophic bacterial counts (HBC), pathogens and opportunistic pathogens, such as Legionella spp., Aeromonas spp., Arcobacter spp., free-living amoeba (FLA), several viral indicators (human adenovirus and polyomavirus JC) and viral pathogens (noroviruses and hepatitis E virus) were analysed for 1 year in inlet and outlet water to assess the removal efficiency of a lagooning system. We observed 2.58 (1.17-4.59) and 1.65 (0.15-3.14) log reductions in Escherichia coli (EC) and intestinal enterococci (IE), respectively, between the inlet and outlet samples. Genomic copies of the viruses were log reduced by 1.18 (0.24-2.93), 0.64 (0.12-1.97), 0.45 (0.04-2.54) and 0.72 (0.22-2.50) for human adenovirus (HAdV), JC polyomavirus (JCPyV) and human noroviruses (NoV GI and GII), respectively. No regrowth of opportunistic pathogens was observed within the system. FLA, detected in all samples, did not show a clear trend. The reduction of faecal pathogens was irregular with 6 out of 12 samples and 4 out of 12 samples exceeding the EC and IE values, specified in the Spanish legislation for reclaimed water (RD 1620/2007). This data evidences that there is a need for more studies to evaluate the removal mechanisms of lagooning systems in order to optimize pathogen reduction. Moreover, surveillance of water used to irrigate raw edible vegetables should be conducted to ensure the fulfilment of the microbial requirements for the production of safe reclaimed water.
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain. xaviako@gmail.com.
authors.forename: X
authors.initials: X
authors.lastname: Fernandez-Cassi
authors.affiliation: Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Reus, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Silvera
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.|Water Hygiene, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria.|ICC Water and Health, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Cervero-Aragó
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Rusiñol
authors.affiliation: Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Reus, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Latif-Eugeni
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Bruguera-Casamada
authors.affiliation: Department of Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Civit
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
authors.forename: R M
authors.initials: RM
authors.lastname: Araujo
authors.affiliation: Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Reus, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Figueras
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Girones
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Bofill-Mas
mesh_terms: D000260:Adenoviruses, Human; D000333:Aeromonas; D016983:Enterococcus; D004784:Environmental Monitoring; D005243:Feces / Q000382:microbiology; D006801:Humans; D007875:Legionella; D059027:Recycling; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000382:microbiology*; D014867:Water; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods
chemical_list: D062065:Wastewater; D014867:Water
keywords: Bacterial removal; Faecal indicator bacteria; Human adenovirus; Lagooning; Reclaimed water; Regrowth; Virus removal