Monitoring and characterization of bacterial populations of two biological air filters during the start up phase

[Abstract] This study aimed to monitor and characterize bacterial populations of two biological air filters during their start up phase (four months). The main objective of this work was to assess the potentiality of a microbiological approach to better understand the evolution of the bacterial populations within biofilters and therefore help to select biomass carrier media. The two biological filters were operated at full-scale (480 m3), filled with organic materials and dedicated to the removal of ammonia and Volatile Organic Compounds (VOCs). The first step of the work consisted in developing an extraction method for the biomass fixed on the solid supports. The second step investigated biofilters’ microbial ecology using molecular tools: DAPI (4,6-DiAmino-2- PhenylIndole), TVC (Total Viable Counts), FISH (Fluorescent In Situ Hybridization) and SSCP (Single Strand Conformation Polymorphism). The findings of the experiments did not show a significant evolution of total bacterial concentrations in biofilms of both biological filters during their start up phase. However, SSCP data analysis underlined important variations in the composition of bacterial populations. Finally, examination of the results highlighted the interest to inoculate organic media in order to reduce the acclimation time of microbial populations

Détection rapide de E. coli dans les eaux de surface par la méthode Coliplage: un outil adapté au suivi de la qualité des eaux de baignade

info:eu-repo/semantics/nonPublishe

An early warning method to detect faecal contamination of river waters

Faecal coliforms (FC) and Escherichia coli enumeration is classically used to monitor the microbiological quality of surface waters. Traditionally, the methods used for the enumeration of these indicator bacteria are culture-based (in liquid or on solid culture media) requiring long incubation times; this makes them unable to rapidly detect faecal pollution. ln this study, an early warning method to detect faecal contamination of river waters was investigated. This method is based on the measurement of the BETA-D-glucuronidase (an enzyme specifie of E. coli) activity (GLUase activity) without any cultivation step using the substrate 4-methylumbelliferyl-BETA-D-glu¬curonide (MUG). The GLUase activity measurement can be performed within 30 min. Significant linear regressions in log-log plots between the glucuronidase (GLUase) activity and, on one hand, FC number estimated by plate count and, on the other hand, E. coli abundance evaluated by the most probable number microplate method were found during the present study. Based on experimentally determined regressions, FC and E. coli abundance were calculated from GLUase activity data. The use of this early warning method was first pos¬itively tested to evaluate the microbiological qua lit y in raw water of a drinking water treatment plant located in an urban area. The method proved to be able to rapidly and accurately estimate the spatial distribution of the microbiological contamination in a large river. Due to its rapidity, reproducibility (better than that of the culture-based methods) and relatively low cost, the GLUase activity measurement appears to be a very useful tool for the monitoring of microbiological pollution in freshwaters.info:eu-repo/semantics/publishe

An operational method for the real-time monitoring of E. coli numbers in bathing waters

The aim of this study was to investigate the potential application of the β-d-glucuronidase (GLUase) activity measurement for the routine detection and quantification of E. coli in marine bathing waters. GLUase activity was measured as the rate of hydrolysis of 4-methylumbelliferyl-β-d-glucuronide. Culturable E. coli were quantified by the most probable number (MPN) microplate method. Both methods were applied to a large set of seawater samples. Significant correlation was found between the log of GLUase activity and the log of culturable E. coli. The mean coefficient of variation (CV) of the GLUase activity was less than 15% at concentrations around the current standards of International regulations whereas the CV of the microplate method was around 30%. When samples were stored at 4 °C and 20 °C, the mean CV of the GLUase activity remained below 15% up to 6 hours after sample collection whereas the range of variation of the microplate method varied between 10 and 50%. We concluded that the GLUase activity is an operational, reproducible, simple, very rapid and low cost method for the real-time enumeration of E. coli in bathing waters and should be preferred to the microplate method. The GLUase activity method should be routinely applied to the rapid enumeration of E. coli in recreational waters and recommendations for its application were suggested to water quality managers.info:eu-repo/semantics/publishe

Réseau PRO : Création d'un réseau d'essais au champ et d'un outil de mutualisation des données pour l'étude de la valeur agronomique et des impacts environnementaux des Produits Résiduaires Organiques recyclés enagriculture

Ce 49ème volume de la Revue Innovations Agronomiques regroupe l'ensemble de la restitution des projets Casdar, présentés le 3 novembre 2015.The "PRO Network” project (2011-2014) has enabled the creation of a national network of trials investigating the effects of agricultural organic waste products (PRO) applications in very different agropedo-climatic situations and for a range of applied PRO. This network was firstly, to harmonize the methods of study and follow-up effects of PRO applied to the field, and secondly to pool data acquired on a wide range of field trials. Have thus been developed: an inventory of 437 tests of PRO in France, an operational methodological guide of field test on the PRO, a method of referencing of the PRO with a first draft of nomenclature, and an information system shared by PRO network and the PRO SOERE. Collected data led to improve the setting of the tools developed within the RMT fertilization & environment (Tools for environmental diagnosis and management of fertilization and the Organic Statute of the soil). Finally, the critical analysis of pooled data sets resulted in recommendations for future trials.Le projet « Réseau PRO » (2011-2014) a permis la constitution d’un réseau national d’essais étudiant les effets des épandages agricoles de produits résiduaires organiques (PRO) dans des situations agropédo-climatiques très différentes et pour une grande diversité de PRO épandus. Ce réseau visait d’une part, à harmoniser les méthodes d’étude et de suivi des effets des PRO épandus au champ, et d’autre part à mutualiser les données acquises sur une grande diversité d’essais au champ. Ont ainsi été élaborés : un inventaire de 437 essais étudiant les PRO en France, un guide méthodologique opérationnel de conduite d’essai de plein champ sur les PRO, une méthode de référencement des PRO et une première ébauche de nomenclature, et un système d’information commun au Réseau PRO et au SOERE PRO. Par ailleurs, les données recueillies ont permis d’améliorer le paramétrage des outils développés au sein du RMT Fertilisation & Environnement (outils de diagnostic environnemental et de gestion de la fertilisation et du statut organique des sols). Enfin, l’analyse critique des jeux de données mutualisés a donné lieu à des recommandations pour les futurs essais