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Le Touquet – Paris-Plage, France

Houari A.,Cergy-Pontoise University | Seyer D.,Cergy-Pontoise University | Kecili K.,Veolia | Heim V.,Syndicat des Eaux dIle de France SEDIF | Martino P.D.,Cergy-Pontoise University
Biofouling | Year: 2013

The kinetic formation of biofilms developing on nanofiltration (NF) membranes was studied for 2 years in the water production unit of Méry-sur-Oise, France. New membranes were set up in a pilot train integrated to the plant and autopsied after operation for 7, 80, 475 and 717 days. The biofouling layer was studied by confocal laser scanning microscope after 4′,6-diamidino-2-phenyindole dihydrochloride and lectin staining, and by attenuated total reflectance-Fourier transform infrared spectroscopy and rheology experiments. Three stages of biofilm growth were discriminated: (1) the presence of sessile microcolonies embedded in an exopolymeric matrix (after filtration for seven days); (2) membrane coverage expansion through microcolony development and biofilm growth in three dimensions (up to 80 days filtration); and (3) biofilm maturation by densification (after filtration for 80-717 days). Biofilm maturation resulted in total coverage of the membrane surface and matrix residue diversification, development of the polysaccharide network, and the strengthening of matrix cohesion through viscosity and elasticity increases. The wettability and permeability of the fouled NF membranes decreased quickly and continuously throughout the biofilm development process. The longitudinal pressure drop (LPD) increased only after the biofilm reached a quantitative threshold. The decline in membrane permeability may be the result of contributions from many fouling mechanisms but the LPD was more substantially influenced by biofilm development. © 2013 Copyright Taylor and Francis Group, LLC. Source

Houari A.,Cergy-Pontoise University | Seyer D.,Cergy-Pontoise University | Couquard F.,Cergy-Pontoise University | Kecili K.,Veolia | And 3 more authors.
Biofouling | Year: 2010

The nanofiltration (NF) drinking water production unit of the Méry-sur-Oise plant (Val d'Oise, France) consists of eight identical filtration trains composed of three stages positioned in steps for a production capacity of 140,000 m3 day-1. To gain a better understanding of the irreversible fouling of the NF membranes, spiral wound modules in operation for 8 years from each of the three stages of the plant were autopsied before and after chemical cleaning and analysis by Attenuated Total Reflection Fourier Transform Infrared spectroscopy, Inductive Coupled Plasma-Atomic Emission Spectrometry, contact angles, adenosine triphosphate (ATP) content measurements, and rheometry. The fouled membranes from the three stages had similar contact angles of approximately 608. Relative infrared signals typical of biofilms were classified in descending order from stage 1 to stage 3. The foulant matter of stages 1 and 2 contained similar but weaker ATP concentrations than stage 3. During rheometry experiments, rotation and oscillation analyses demonstrated that the biofilm of stage 3 was less viscous and less elastic than the biofilms of stages 1 and 2.After cleaning, all the parameters analyzed demonstrated a quantitative decrease in the fouling matter at the NF membrane surface, but a biofilmwith intact viscoelastic properties (unchanged G′ and G″ values) remained at the membrane surface for the three stages. The persistence of biofilm material with intact mechanical properties at the NF membrane surface after chemical cleaning may result in permanent permeability decreases. © 2010 Taylor & Francis. Source

Cheifetz N.,Veolia | Sandraz A.-C.,Veolia | Feliers C.,Veolia | Gilbert D.,IRSTEA | And 2 more authors.
Procedia Engineering | Year: 2015

Supplying modern water systems in smart cities requires the ability to monitor water quality in the production plants and the distribution network. Protection against accidental or intentional events is usually based on an Early Warning Detection System (EWDS) to minimize the impact of any contamination [1]. A major issue is positioning online sensors along the water distribution network to ensure the best protection at minimum cost. Several contributions for tackling such problem have been proposed during the last decade, including a scientific challenge comparing 14 methodologies [2] and two reviews of about 150 articles [3,4]. Currently there is no consensus about algorithms or design objectives to use, and such a problem is NP-hard [5,6]. In this paper, a greedy approach is proposed to near-optimally solve the sensor placement problem dealing with large-scale water systems. This methodology is designed to integrate both the specificity of the studied network (expert/prior knowledge) and flexibility related to the uncertainty of the nature, time, and duration of contamination injections. The method is illustrated to minimize the expected fraction of the exposed population on the largest network in France (about 100,000 nodes, 600,000 connections, above 8,000 km of pipes). Costly approaches in terms of computation time, such as MIP (Mixed-Integer Programming) and exhaustive search cannot scale to large networks. A sensitivity analysis is presented using the greedy approach on a sub-network which leads to choose the number of sufficient contamination simulations and the concentration threshold used to detect contaminations. The extensive experiments allow us to highlight the effectiveness and the rapidity of the proposed approach. © 2015 The Authors. Published by Elsevier Ltd. Source

Boucherie C.,Veolia | Lecarpentier C.,Veolia | Fauchon N.,Veolia | Djafer M.,Veolia | Heim V.,Syndicat des Eaux dIle de France SEDIF
Water Science and Technology: Water Supply | Year: 2010

Ozonation plays an essential role in water disinfection to inactivate viruses, bacteria and some parasites (Giardia). Ozone treatment rates to attain disinfection goals also result in oxidation reactions of emerging pollutants. Pharmaceuticals-except Ciprofloxacin-are very reactive to ozone: they are removed as early as the transfer compartment outlet even at an ozone treatment rate of less than 1 g/m3. Glyphosate, AMPA, Amitrole and Diuron-the four major pesticides in the Seine, Marne and Oise rivers-are reactive to ozone. Twenty-one pesticides are only partially reactive to ozone and an additional "GAC filtration" is needed to remove them. Further investigations have been planned to study the removal of Phthalates, Nonylphenols and Hormones by combining the "Ozone" and "GAC filtration" process units. © IWA Publishing 2010. Source

The energy challenges for the Syndicat des eaux d'ile-de-France (Sedif), the biggest drinking water utility in France, are particularly significant, since its facilities for the production and distribution of drinking water, in particular the pumping station, consume the electrical equivalent of a town of 25,000 inhabitants (ca. 200 GWh per year). This consumption generates 15,700 tonnes in CO2 equivalent annually. Furthermore, the Sedif area has numerous sites with a strong potential for the production of renewable energy: 21 photovoltaic, k wind, 15 geothermal and 10 close to a heating network. In order to meet these challenges, the Sedif wishes to integrate into its energy policy, the EU targets to reduce greenhouse gas (GHG) emissions by 20%, to increase energy efficiency by 20% and to increase the share of renewable energy to 20% of its overall consumption between nowand 2020. In order to do this, the public utility has set these targets for the one part, within the scope of its project ownership and for the other part, within that of the operations delegated to Veolia Eau dl̂le-de-France SNC. The energy consumption of 20 sites, which are undergoing renovation work between 2011 and 2015, will be better controlled, through the installation of high-efficiency motors or transformers and the replacement of thermal ozone destructors. Five pilot projects to produce or use renewable energy have been undertaken since 2010: the implementation of photovoltaic installations for power production on the main units' roofs, the installation of photovoltaic panels on the tanks at Chatillon and on the new tank at Villejuif, the erection of a wind turbine on the new tank at Palaiseau, and the replacement of the heating systems in the production plant at Choisy-le-Roi. The remaining improvement levers are those that Sedif is imposing on its delegatee, Veolia Eau d'Îlede-France SNC, within the framework of a new 12-year contract (from 1st January 2011). Source

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