Authors: X FernandezCassi C Silvera S CerveroAragó M Rusiñol F LatifEugeni C BrugueraCasamada S Civit R M Araujo M J Figueras R Girones S BofillMas
Publish Date: 2016/05/19
Volume: 23, Issue: 16, Pages: 16816-16833
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 freeliving 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 258 117–459 and 165 015–314 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 118 024–293 064 012–197 045 004–254 and 072 022–250 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 waterThe study reported here was partially founded by programa Recercaixa 2012 ACUP00300 and AGL201130461C0201/ALI of the Spanish Ministry of Science and Innovation and Consolidated Research Groups Program of the Catalan Government 2014SGR529 and VirBaP 2014SRG914 Xavier FernandezCassi and Fadua LatifEugenín acknowledge the AGAUR Agency of the Catalan Government and the Universitat Rovira i Virgili respectively which supported their PhD grants The authors would like to thank the lagooning system manager Conrad Martorell for his collaboration during this project
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