title: Fecal contamination of wastewater treatment plants in Portugal.
abstract: Reutilization of effluents from wastewater treatment plants (WWTP) for non-potable applications is increasing due to the reduction of sustainable water resources. These products mostly come from municipal WWTP and also from slaughterhouses effluents. The microbiological certification of these products is mandatory before their discharge into the environment. This study evaluates if the treatment applied in WWTP to municipal waters or to poultry slaughterhouse effluents distributed over the Portuguese continental territory is efficient in reducing the microbiological risk associated with the reutilization of those wastewaters and sludges. Fecal indicators Escherichia coli and enterococci were evaluated in 42 and 24 wastewater samples from 14 municipal WWTP and 8 poultry slaughterhouse treatment plants, respectively, by the conventional culture method and a rapid Fluorescent in situ hybridization (FISH) technique. Bacterial enumeration in inflow water from most WWTP was rather high (generally >10(5) cells/ml), for both E. coli and Enterococcus spp., and the bacterial quantification by FISH was generally higher than enumeration by the conventional culture method. In both types of treatment plants studied, bacterial load from effluents and sludges was not statistically different from the inflows, indicating that the treatment applied seems to be equally unable to reduce the microbiological load of the effluents. These findings may jeopardize the safe reuse of treated wastewaters in agriculture and the quality of the water environment. Therefore, products like water, sewage sludge, and biosolids originated from the municipal and slaughterhouse WWTP studied should not be reutilized, and effluents treatment should be urgently reviewed.
authors.affiliation: CIISA/Faculdade de Medicina Veterinária da Universidade de Lisboa, Polo Universitário da Ajuda, 1300-477, Lisbon, Portugal. moliveira@fmv.ulisboa.pt.
authors.forename: Manuela
authors.initials: M
authors.lastname: Oliveira
authors.affiliation: CIISA/Faculdade de Medicina Veterinária da Universidade de Lisboa, Polo Universitário da Ajuda, 1300-477, Lisbon, Portugal.
authors.forename: Isa
authors.initials: I
authors.lastname: Serrano
authors.affiliation: CIISA/Faculdade de Medicina Veterinária da Universidade de Lisboa, Polo Universitário da Ajuda, 1300-477, Lisbon, Portugal.
authors.forename: Sofia
authors.initials: S
authors.lastname: Van Harten
authors.affiliation: ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050-313, Porto, Portugal.|CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas, 289, 4050-123, Porto, Portugal.
authors.forename: Lucinda J
authors.initials: LJ
authors.lastname: Bessa
authors.affiliation: CIISA/Faculdade de Medicina Veterinária da Universidade de Lisboa, Polo Universitário da Ajuda, 1300-477, Lisbon, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Bernardo
authors.affiliation: ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050-313, Porto, Portugal.|CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas, 289, 4050-123, Porto, Portugal.
authors.forename: Paulo Martins
authors.initials: PM
authors.lastname: da Costa
mesh_terms: D000003:Abattoirs; D000383:Agriculture; D000818:Animals; D016983:Enterococcus; D004926:Escherichia coli / Q000235:genetics; D005243:Feces / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D011174:Portugal; D011200:Poultry; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000382:microbiology*
chemical_list: D012722:Sewage; D062065:Wastewater
keywords: Agriculture; Contamination; Effluents; Enterococcus spp.; Escherichia coli; FISH; Wastewater treatment plant; Water reuse