Subsurface horizontal flow constructed wetlands (HFCW) and vertical flow constructed wetlands (VFCW) have been compared regarding their efficiencies on microbiological indicators removal. Seven types of HFCWs and two types of VFCWs have been monitored for several years. Fecal coliforms, E. coli, somatic coliphages and F-specific bacteriophages were analyzed in the influent and effluents of each system. All constructed wetlands monitored were planted with Phragmites australis but have different design characteristics and operation variables. All data were statistically treated (SPSS v17) in order to analyse the effect of design and operation variables on each microbiological indicator. VFCWs were more efficient than HFCWs systems when considering removal rates per surface for all the microbiological indicators (cfu or pfu removed/m2.d). Nevertheless, considering mean removal efficiencies (in log units), results did not show statistically significant differences. The hydraulic retention time was the key parameter regarding filter disinfection capacity in both types of filters. Bacterial indicators were removed at a higher rate than viral indicators.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [Axe_IRSTEA]TED-EPURE | International audience | With decentralized treatment system development, a new concern emerges: the future of the septage. The aim of this paper is to assess the feasibility of septage treatment by SDRB, and to compare its efficiencies to those of activated sludge treatment in same conditions. The study took place on ten 2m² pilot-scales SDRB. Different designs and operation conditions have been tested on sludge treatment efficiency and will be presented as: (i) the top filtration layer (sand or compost), (ii) the load (from 30 to 50 kgSS/m-2/y). After one year and half commissioning period, we focus on the results obtained at nominal loads presenting: sludge characteristic, filtration efficiency, percolate quality and sludge deposit behaviour. Although results show better filtration efficiency for activated sludge (98.4%) than for septage (87.5%), the feasibility of septage treatment with drying reed bed has been demonstrated. Sludge accumulation is about 7.9 cm/y, when fed at 50 kgSS/m-2/y, and dry matter content of the sludge can reach 70% in summer period. The paper will present sludge characteristics, system efficiency, to finish on design and operation condition recommendations for SDRB treating septage.

This paper presents the main results of a study on the influence of driving style on fuel consumption and pollutant emissions of diesel passenger car in urban traffic. Driving styles (eco, normal or aggressive) patterns were based on the “eco-driving” criteria. The methodology is based on on-board emission measurements in real urban traffic in the city of Madrid. Five diesel passenger cars, have been tested. Through a statistical analysis, a Dynamic Performance Index was defined for diesel passenger cars. Likewise, the CO, NOX and HC emissions were compared for each driving style for the tested vehicles. Eco-driving reduces by 14% fuel consumption and CO2 emissions, but aggressive driving increase consumption by 40%. Aggressive driving increases NOX emission by more than 40%. CO and HC, show different trends, but being increased in eco-driving style.

The MAPPE GIS based multimedia model is used to produce a quantitative description of the behaviour of γ-hexachlorocyclohexane (γ-HCH) in Europe, with emphasis on continental surface waters. The model is found to reasonably reproduce γ-HCH distributions and variations along the years in atmosphere and soil; for continental surface waters, concentrations were reasonably well predicted for year 1995, when lindane was still used in agriculture, while for 2005, assuming severe restrictions in use, yields to substantial underestimation. Much better results were yielded when same mode of release as in 1995 was considered, supporting the conjecture that for γ-HCH, emission data rather that model structure and parameterization can be responsible for wrong estimation of concentrations. Future research should be directed to improve the quality of emission data. Joint interpretation of monitoring and modelling results, highlights that lindane emissions in Europe, despite the marked decreasing trend, persist beyond the provisions of existing legislation. An spatially-explicit multimedia modelling strategy was applied to describe the historical distribution of γ-HCH in European soils and surface waters.

L'article présente l'application de l'Analyse du Cycle de Vie (ACV) à un système d'assainissement complet, incluant le réseau d'égout. Il présente d'abord les hypothèses retenues pour l'ACV concernant les deux systèmes de traitement des eaux usées ayant tous les deux la même charge nominale quotidienne de la DBO 5 et associés au même réseau d'égouts. Ces systèmes correspondent respectivement à (i) un "filtre planté de roseaux à lit vertical (VFCW)" pour lequelle un inventaire détaillé des flux émis et des ressources consommées a été élaboré et (ii) une STEP à « boues activées » boues » issue de la base de données d'ACV Ecoinvent LCI. Les résultats d'ACV soulignent l'importance de l'eutrophisation qui peut facilement s'expliquer par la suppression incomplète de l'azote total et du phosphore total dans un VFCW. De façon plus surprenante, l'impact du réseau semble considérable. Enfin, l'article analyse l'applicabilité et les limites de l'ACV pour les systèmes de traitement des eaux usées. / The article presents the application of Life Cycle Assessment (LCA) to a complete sanitation system including the sewer network. It first describes the LCA hypothesis which concerns two types of waste water-treatment plant with the same daily nominal load in BOD5 and associated to the same sewer network derived from the Life Cycle Inventory (LCI) database Ecoinvent. The two wastewater treatment systems compared are (i) a Vertical Flow Constructed Wetlands (VFCW) for which a detailed inventory was elaborated and (ii) an activated sludge stemming from the LCI database Ecoinvent. LCA scores of VFCW highlight the importance of eutrophication which can be easily explained by the incomplete removal of total N and total P in a VFCW. In a more surprising way, the impact of the network seems considerable. Finally, the article analyses the applicability and limitations of LCA for wastewater treatment with regard to water quality and the needed improvements of water status in LCA.

Poster session | International audience