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Measuring aerosol size distributions with precision is important to understand the transmission of infectious diseases causing pneumonia-like illnesses, including Legionnaire’s disease and COVID-19. Accurate size measurement can help guide the identification of risk mitigation strategies, a challenging task as the size of pathogen carrying particles can change due to evaporation. Using oil and water-based particles, we compare four measurement instruments that provide aerosol size distributions relying on different measurement principles; phase doppler anemometry, light scattering, electrical mobility and aerodynamic impaction. The size distributions obtained from the different measurement instruments are consistent for oil-based particles but differ significantly for particles experiencing evaporation. Experiments were conducted to quantify the differences in measurement caused by evaporation as well as the measurement losses. The size range covered by the four instruments is from 0.025 to 10 µm. Finally, an approach based on the complete drying of a salt solution is presented to obtain the size distribution at the source of the aerosol generation. Understanding of the infectious dose and the pathogen concentration at the source, the most dangerous size ranges of the aerosols can thus be determined, and actions can be taken to reduce the propagation of these particles.

Faucet aerators that form aerated water jets generate aerosols, which can constitute a risk of infection if the water is contaminated, particularly for vulnerable individuals near the sink. In this study, we characterize the size and trajectory of water droplets produced from an aerated jet. The detected particle diameter ranged from 3 to 150μm. The concentration of droplets in the air varied from near-zero to a maximum of 2×10

The exhaust detritiation system (EDS) of the Joint European Torus (JET) active gas handling system removes tritium from exhaust gases and contaminated air prior to discharge to stack. The system was replaced prior to JET’s tritium experimental campaign due to corrosion damage. In this paper, the following topics are presented: system function and description, corrosion and failure of the previous EDS, enhancements for the replacement EDS including testing of acid passivation column, commissioning experience, operating experience and performance. Acids including hydrofluoric were generated in catalytic recombiners following inadvertent halogen ingress. Pitting corrosion was identified with breakthrough failure of condensate pipework. To mitigate a recurrence, a novel acid passivation sub-system was designed. The acid passivation testing demonstrated successful performance of the design and calcium-hydroxide passivation packing tested, with acids below the limit of detectability at the test column outlet. Issues encountered during commissioning are described and key performance metrics such as detritiation factor reported. Finally, operational issues and system performance is presented.

This article describes recent improvements made in the design process of offshore flexible pipes. These improvements consider the more precise complex geometry and architecture of the flexible pipes, while considering their corrosive environment (high pressure, high temperature, acid gases (CO2, H2S), sea water, etc.) and the relevant physics. MOLDITM, the design software that was developed 20 years ago to predict flexible pipes annulus environment, has been constantly upgraded to increase its representativeness: use of chemical potential or fugacity to better describe the mass transport, improvement of the thermodynamic module to better describe the interaction between chemical species and allow to model the purging through gas release valves. Recently, a major advance has been made allowing to cope with flooded annulus flexible pipes. When the annulus is flooded, the tortuosity produced by the presence of steel wires inside the annulus can take a major importance. Therefore, a new model, named 3DIFF, has been developed to describe the 3-dimensional characteristics of the annulus and its impact on fugacity profile across the structure. Depending on permeation properties of each layer, the result is that the presence of water can produce a fugacity gradient within the annulus. This heterogeneity must be considered during the design process to be fully representative of service conditions and allow to select flexible pipes materials with confidence. Experimental devices used to generate permeation database are under constant evolution to study even more complex mechanisms such as the diffusion process in a flooded tortuosity or the compression effects of polymeric material on their permeation properties.

International audience; This paper discusses the effect of porosity and hydrostatic pressure on diffusion kinetics and equilibrium water uptake in a semicrystalline fluoropolymer. Water sorption experiments at atmospheric pressure and under water pressures up to 250 MPa were carried out during 18 months at 40°C on reference and poroussamples. Porosity of samples was induced due to a cavitation process occurring at the highest triaxiality area of waisted and notched specimens during tensile tests.Water uptake was found to be very sensitive to porosity, showing an increase in samples with a high void fraction. On the other hand, water content decreased with increasing pressure suggesting a compaction of the porous space in which water can be stored. Two models describing this water uptake behaviour wereconsidered. The first is a classical model which assumes that sorption occurs only by diffusion following Fick’s law. Fick’s model was found to be in agreement with the experimental results. A “Langmuir-type” sorption model was also proposed to describe water uptake in porous samples, considering a two-phase watertransport mechanism: one portion of the absorbed water diffuses through the polymer matrix and the other portion is stored in voids. This model was implemented in a user subroutine using ABAQUSTM software and simulations were confronted to experimental sorption curves showing satisfactory agreements. The potential of the Langmuir-type sorption model resides on its availability to be coupled to a poro-mechanical model, in order to improve the understanding of coupling between the mechanical behaviour and water sorptionmechanism in a porous polymer.

International audience; The aim of this work was to characterize solute transfer between static and dynamic water during percolation through a solid leach bed reactor. A new experimental procedure was set up to measure the solute exchange rate between macro-and micro-porosity. Tracer tests were performed in closed-circuit recirculation experiments. The water behavior was modeled by a multiphase flow model in a double porosity medium using a previously published methodology. The solute exchange rate between static and dynamic water was described by first-order kinetics. The methodology was applied to wheat straw and solid cow manure beds. The solute exchange rate (hs was 0.054 and 0.324 h−1) for wheat straw and solid cow manure, respectively. The measured data was used to improve the prediction capacity of a CFD tool. The results of this work could be used to develop appropriate leachate recirculation strategies to optimize full-scale dry batch anaerobic digestion processes.

Corrosion is a key issue for operators in the oil and gas industry since production fluids contain some water and both CO2 and H2 S acid gases. In this context, this paper illustrates the development of a reactive barrier polymer against corrosion by H2 S of offshore flexible pipes. The role of this reactive material, called anti-H2 S material, is to avoid H2 S reaching the structural steel layers of the flexible pipe during the whole service life of the structure, usually 20 years, and hence to place the steel layers in a sweet service environment. Placed between the existing pressure sheath and the steel layers, the anti-H2 S material has the ability to neutralize H2 S during its diffusion within the material. The neutralization is ensured by an irreversible chemical reaction on reactive components that are dispersed in the material. The raw material selection is based on both accurate requirements for their use in a flexible pipe and expected performances in a sour service environment over a long period of time. Some laboratory qualifications and experimental techniques are used to qualify the behavior of the material and build the material database. A dedicated multiphysics model is developed based on the coupling of permeation mechanisms and gas-solid reactions. Qualification of both the material and the model is performed thanks to middle-scale and full-scale tests conducted in representative sour service conditions.

Tritium Extraction Systems (TES) in future nuclear fusion power plants will recover tritium (radioactive hydrogen isotope) from the outlet stream of the breeder blanket, where tritium will be produced and purged out by a high flow rate of helium. This work presents an experimental assessment of the performance of a MFI zeolite hollow fibres membrane for the tritium removal and pre-concentration in the first stage of TES. A set-up was built for the permeation experiments of hydrogen and helium single gases and the separation experiments of binary mixtures of those gases. Numerous assays were performed for binary mixtures of H2 and He under various operating conditions (feed and permeate pressures, temperature, and feed composition) to assess the membrane separation performance. Optimal separations were achieved at the lowest temperatures (around room temperature) and the lowest hydrogen molar fraction (0.22). H2 and He permeances ranged 0.70–2.3 and 0.43–0.74 μmol m−2 Pa−1 s−1, respectively, corresponding to membrane selectivities of H2 over He between 1.2 and 4.0. By regulating the feed pressure, hydrogen recovery factors around 50% were attained without compromising the maximum enrichment factor of 1.5. These preliminary data enable the design of a multi-stage separation process complying with the strict requirements for the tritium recovery and enrichment in a nuclear fusion power plant.

International audience; The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency.

Paper and cardboard stand for the major biodegradable organic fraction of most of municipal solid waste (MSW). This article aims at discussing the possible positive impact of a thin shredding of this fraction on its biodegradability under mesophilic anaerobic conditions, either for landfilling or for digestion in industrial reactors. For that purpose, BMP tests were performed on two types of paper and cardboard mixtures: one sorted from a complex landfill French MSW income, one built from source separated papers and cardboards. For both of these substrates, comparison was made between assays on large pieces of waste and assays on tiny shredded waste (powder particles of less than 1 mm diameter). For the second substrate, assays at two different inoculation levels were performed. All results are discussed both in terms of maximal methane conversion yields and in terms of kinetic rates. The main conclusion is that shredding does not improve methane potential of paper and cardboard, neither the biogas production rates. This leads the authors to put forward the hypothesis that shredding does not significantly either increase enzyme accessibility to cellulose nor favor the surface bacterial colonization, although it strongly affects the macrostructure of the waste.

For more than 40 years, flexible pipes have been used for subsea oil and gas transportation. One of the main benefits of this technology is that, through an unbounded assembly of steel and polymer layers, the load bearing layers of the pipes are not in direct contact with the transported fluid and the corrosive components such as hydrogen sulphide (H2S). However, over a long period of time, small quantities of gas, including H2S, are able to permeate through the polymer pressure sheath and reach the metallic structural layers. To avoid this, a new polymer layer able to completely prevent H2S from reaching the annulus has been developed. This layer is called the anti-H2S layer. As part of the qualification program, an H2S exposure full scale test was performed. A flexible pipe structure with an anti-H2S layer was tested in harsh conditions, continuously exposed to gas containing methane mixed with 1.5% H2S and 5% CO2 at 200 bar (2902 psi) and 80°C (176°F) for 600 days. Several successful integrity tests were performed along the qualification program. After the H2S exposure test, the full scale prototype underwent a hydrostatic pressure test. Pipe dissection and laboratory material characterization were then performed to confirm the efficiency of the anti-H2S layer. The positive result obtained in the long term H2S exposure full scale test and qualification program demonstrate the efficiency of the anti-H2S layer. The use of the anti-H2S layer concept creates new opportunities in terms of flexible pipe design, especially for ultra deep water and very sour fluid transportation.

International audience; This work aimed at assessing water percolation through a solid cow manure leach bed in dry batch AD processes. A laboratory-scale percolation column and an experimental methodology were set up. Water behaviour was modelled by a double porosity medium approach. An experimental procedure was proposed to determine the main hydrodynamic parameters of the multiphase flow model: the porosity, the permeability and the term for water exchange from macro- to micro-porosity. Micro- and macro-porosity values ranged from 0.42 to 0.70 m3⋅m-3 and 0.18 to 0.50 m3⋅m-3. Intrinsic permeability values for solid cow manure ranged from 5.55⋅10-11 to 4.75⋅10-9 m2. The term for water exchange was computed using a 2nd order model. The CFD tool developed was used to simulate successive percolation and drainage operations. These results will be used to design leachate recirculation strategies and predict biogas production in full-scale dry AD batch processes.

International audience; A control system for limiting N2O emissions in a SBR treating an ammonium rich effluent (~500 mgN.L-1) with nitrification / denitrification over nitrite is presented. This system is based on the use of derivatives of DO and ORP signals for on line control of aerobic and anoxic periods. During the 120 days of operation, the effect of different operating conditions on N2O emissions during nitrification has been analyzed. Experimental results have highlighted the effect on N2O emissions of: HNO2 concentration, DO concentration and the presence of COD during nitrification. The control system allows reducing the N2O emission factor (N-N2O per N removed) to less than 1%.

Temperature-phased anaerobic digestion with a 50–70 °C pre-treatment is widely proposed for sludge. Here, such a sludge pre-treatment (65 °C) was studied against the physical, enzymatic and biodegradation processes. The soluble and particulate fractions were analysed in terms of biochemical composition and hydrolytic enzymatic activities. Two kinetics of organic matter solubilisation were observed: a rapid transfer of the weak-linked biopolymers to the water phase, including sugars, proteins or humic acid-like substances, to the water phase, followed by a slow and long-term solubilisation of proteins and humic acid-like substances. In addition, during the heat treatment a significant pool of thermostable hydrolytic enzymes including proteases, lipases and glucosidases remains active. Consequently, a global impact on organic matter was the transfer of the biodegradable chemical oxygen demand (COD) from the particulate to the soluble fraction as evaluated by the biological methane potential test. However, the total biodegradable COD content of the treated sludge remained constant. The heat process improves the bio-accessibility of the biodegradable molecules but doesn't increase the inherent sludge biodegradability, suggesting that the chemistry of the refractory proteins and humic acids seems to be the real limit to sludge digestion.

The EN 3665 test is used to compare the filiform corrosion of aluminium substrates pretreated with Cr6+ and coated with different powder paints. The influence of the mechanical properties (tensile test and adhesion test), the chemistry (DSC and FTIR analysis) and the physical properties (oxygen and water permeations) of the paints on filiform corrosion is measured. The corrosion promoted filaments are studied morphologically and electrochemically. Their growth seems to be due to a combination between specific mechanical properties of the paints and their adherence on the pre-treated substrates. The influence of the paint thickness is also illustrated.

The complex melting behaviour and crystallization kinetics of polyhexamethylene terephthalate (PHT) and its copolymers with isophthalic acid (PHT col) have been explored using differential scanning calorimetry (DSC) and simultaneous time resolved synchrotron radiation wide angle and small angle X-ray scattering (WAXS and SAXS). Special attention has been paid to the presence of isophthalic chain defects and to crosslinking on the rate of crystallization. Kinetic data have been tentatively analyzed using Avrami parameters for the global crystallization and the Hoffman-Lauritzen equation for the separation of the factors governing spherulite growth rate.

Abstract Flexible pipes are extensively used for oil and gas development and thus transport the corrosive fluids of the production flow. These corrosive components (water, carbon dioxide or hydrogen sulfide) do not enter in direct contact with the structural steel layers of the pipe. However, they will diffuse through the pressure sheath and may induce corrosion phenomena on the structural layers. H2S gas could thus be present in the annulus. It is then necessary to use pressure vault and armour wires made of sour service steel grades instead of sweet service steel grades. In addition to the cost impact, the choice of these sour service steel grades with often lower mechanical performances has a direct influence on the overall design of the flexible pipe as they will result in structures with higher weight. Such a weight increase can be a disadvantage, for example in the case of ultra deep water applications. To prevent H2S from reaching the annulus of the pipe, a new thermoplastic material was developed. Components in the sheath material react with H2S and prevent it from diffusing and reaching the annulus. The use of this new ‘Anti-H2S’ layer will ensure a H2S free environment in the flexible pipe annulus. Considering that the steel layers will not be exposed to H2S, no degradation linked to the presence of H2S needs to be taken into account in the choice of the structural steel layers constitutive of the annulus. Consequently, the use of high steel grades layers with reduced thickness will be possible, reducing the cost and the weight of the flexible pipe. In addition, the ‘Anti-H2S’ layer makes it possible to propose flexible pipes for applications with high H2S contents, for which no solution could be proposed otherwise.

Due to H2 S pressure build-up in annulus, the use of sour service steel grades is required in some cases. For ultra deep water fields where the flexible pipe top tension is critical, high weight of the structural steel layers combined with lower mechanical properties (about 950MPa) of the sour grade materials is a disadvantage. The generic flexible pipe design avoids any direct contact between the bore environment (production fluids, injection fluids, etc) and the steel layers of the flexible pipe. However, diffusion of active components such as water, carbon dioxide, hydrogen sulfide, etc, through the thermoplastic sheaths could lead to corrosion exposure of metallic layers between the thermoplastic sheaths. In order to reduce the weight of the flexible pipe structure to reduce riser top tension, high strength grade steel layers (>1200MPa) can be used with reduced thickness, considering that the steel layers will not be exposed to H2 S coming from the bore fluid. This is now achievable even when H2 S is present in the bore by use of a new reactive polymer layer, which will ensure a H2 S free environment in the flexible pipe annulus. The new “Anti-H2 S” layer will chemically react with the H2 S, leading to a complete absence of H2 S exposure to steel layers during the service life of the pipe. In addition, the “Anti-H2 S” layer makes it possible to propose flexible pipes for applications with high H2 S content for which no acceptable solution would otherwise be found. This paper will present the theoretical background supporting the new Anti-H2 S layer concept, along with the qualification works carried out both at laboratory scale and on full flexible pipe structures. It will also focus on the design/calculation methodology applicable to this new sheath. Introduction of the “Anti-H2 S” layer results in that: - Flexible pipes can now be proposed for applications with high H2 S contents; - Sweet service high strength steel grades can be used in flexible pipe annulus even with the presence of H2 S into the bore of the pipe; - The weight of the flexible pipe is reduced.Copyright © 2011 by ASME

International audience; Sludge reduction is one of the major challenges in biological wastewater treatment. One approach is to increase the sludge degradation yield together with the biodegradation kinetics. Among the various sludge pretreatment strategies proposed, thermal pretreatment at around 65 degrees C was described as promising. The enhancement in the biodegradation activity due to the selection of thermophilic hydrolytic bacteria was proposed, but further experiments are needed to demonstrate the specific role of these bacteria. In this study, concentrated activated sludge grown at 20 C was subjected to thermal treatment at 65 C for different periods. The originality of the work relied on a polyphasic approach based on the correlation between kinetics (chemical oxygen demand, COD; mixed liquor suspended solids, MLSS), bacterial activity (respirometry) and bacterial community structure (phylochip monitoring) in order to characterize the mechanisms involved in the thermal reduction of sludge. The bacterial activity in the aeration basin decreased to a very low level when recycling sludge was treated at 65 degrees C from 13 to 60 h, but then, started to increase after 60 h. In parallel to these fluctuations in activity, a drastic shift occurred in the bacterial community structure with the selection of thermophilic bacteria (mainly related to genera Paenibacillus and Bacillus), which are known for their specific hydrolases.

cited By 43; International audience; Hydrogen induced cracking (HIC) of line pipe steel was investigated through immersion testing and hydrogen permeation measurements. At constant pH and hydrogen sulphide partial pressure (pH2S), the extent of HIC was found to depend on exposure time until a stable level was reached. The time to reach this stable value is affected by pH and pH2S. Results of permeation experiments confirmed that HIC is linked with the increase of hydrogen concentration in the steel. It is also shown that low severity requires longer exposures to reach equilibrium. This must be taken into account for HIC testing in mildly sour environment. © 2009 Elsevier Ltd. All rights reserved.

The selection of materials for application in the oil and gas industry in environments containing hydrogen sulphide (H 2 S) is an important matter for the safety of equipments. In the presence of H 2 S, hydrogen atoms originating from the cathodic corrosion reaction can diffuse into the steel, resulting in cracking mechanisms such as hydrogen-induced cracking (HIC) or sulphide stress cracking (SSC). For the SSC cracking mode, a diagram defining different regions of environmental severity was established in the 1990's. The requirements for SSC testing of steels in a given environment are well defined and accepted by the industry. On the other hand, fit-for-purpose (FFP) testing for HIC remains a subject of debate. The most common practice consists in 96 hours exposure under 1 bar H 2 S. But this test environment is extremely severe, and is often considered to be too conservative for the selection of steels for use in mildly sour environments. However, a universally applicable FFP test method for HIC has not yet been established. In addition to pH and H 2 S partial pressure, test duration is another major parameter for HIC testing. Therefore, this experimental study was launched to investigate the impact of time of exposure on HIC. Experiments consisted of HIC exposure tests based on the NACE TM0284-2003 standard method. Experiments were conducted in different nodes of the pH-pH 2 S diagram respectively between pH 6.5 and 3.5, and between 10 mbar and 1 bar of H 2 S. For each condition, tests with different times of exposure were realised, from only a few hours and up to three months. Characterisation of HIC consisted in ultrasonic testing. Permeation experiments were also performed in selected pH-pH 2 S conditions. Permeation transients were analysed for calculation of diffusion coefficients. Modelling of hydrogen profiles in HIC specimens was then realised, and compared with the results of HIC immersion tests. For each test condition, it was possible to draw the evolution with time of the extent of HIC. Depending on the environment, the minimum duration necessary to initiate HIC was extremely variable, from a few hours in the most severe conditions to several weeks in low severity conditions. The extent of cracking at equilibrium also seemed to vary with pH and H 2 S. A good correlation was found between HIC and permeation results, confirming that HIC is strongly linked with the increase of hydrogen concentration in the steel. These results confirm that low severity conditions require longer exposures to reach equilibrium levels of internal hydrogen. This must be taken into account for FFP HIC testing in mildly sour environment. With that aim, permeation experiments could represent an interesting technique to assess the time to reach a certain level of hydrogen in the material.

To apply the directive 1999/92/EC, the employer shall ensure that the work equipment, used in place where explosive atmosphere may occur, are maintained so as to reduce at most explosion risks. The maintenance shall be realized in a permanent concern for keeping the protection level of work equipment in ATEX. This level shall never be either modified or deteriorated. That's why this activity shall be carried out only by workers who have been trained to the specificity of the protection types and shall be the matter of specific follow-up and management. The safety shall also be guaranteed if the maintenance and overhaul of equipment are sub-contracted. We will establish technical and organizational recommendations to ensure a safe maintenance of ATEX equipment. On a technical point of view, the international standards IEC 60079-17 et IEC 60079-19 deal with inspection, maintenance, repair and overhaul of electrical apparatus for explosive gas atmospheres. With regard to the mechanical equipment, we will produce some elements of our referential ISMATEX and SAQRATEX. To deal with the management of maintenance, we shall particularly watch over the identification of the ATEX equipment, the archiving of technical documentation, the establishment of maintenance planning, and to the traceability of the interventions. We shall also be sure that the maintenance workers are correctly trained and experimented, either they are internal workers or sub-contractors.

International audience; Mechanical friction and impacts is still today a main cause of ignition of explosive atmospheres (ATEX) in the industry and this trend seems to be stable in time. This situation certainly results from a significant gap of knowledge in the underlying mechanisms so that the parameters to play on are not precisely identified. In this programme of European dimensions, the process of degradation of the mechanical energy into heat during friction and impacts have been studied. An extensive experimental programme is presented to this end. The mechanisms of dissipation of the mechanical energy into heat during friction has been studied with rubbing machines in which a slider equipped with temperature sensors rubs against a rotating wheel. For impacts, a new device has been developed using a special "air driven cannon" to propel a projectile accurately up to 50 m/s onto an inclined target. A very significant effort has been reserved to the investigation of the ignition mechanisms, not only for ATEX but also for dust accumulations. Some "simple" modelling is proposed on purpose of practical applications. For frictional situations, a critical rubbing power is calculated without any limitations about any lower boundary concerning the rubbing velocity. For "impacts", the relevant parameter for ignition is not the kinetic energy of the projectile but its velocity and the nature of the materials.

Three-layer polyolefin coatings are being used classically for external pipeline protection in the oil and gas industries over years although cathodic protection is also applied. They are supposed to provide efficient and sustainable corrosion protection to the pipe steel over 20 years service or more, including exposition to humidity and temperature (cycling conditions). However, the permeability of polyolefin topcoat to water is not negligible and thus does not prevent water ingress into sub-layers after a few months service. Then soaked water in the vicinity to the steel pipe conveying hot effluents possibly induces hydrolysis of the epoxy primer layer and interfacial bonds to metal. This could raise questions over the long term corrosion control. Therefore, the inspection of the water ingress and the investigation of the long-term barrier properties of primer and adhesives layers when exposed to water are mandatory. This paper examines the use of Electrochemical Impedance Spectroscopy (EIS) to monitor durability and anticorrosion properties of three-layer coatings while exposed to water at 60 °C (maximum service temperature). The objective was to investigate the water ingress within a bilayer coating with respect to sublayer thickness. EIS was used to characterise the water uptake but also the long term barrier properties of coatings on industrial tubes. In complement, gravimetry measurements were also performed during ageing on FBE primer coated panels cut from industrially coated tubes to determine the water uptake kinetics using classical destructive techniques. Degradation mechanisms of 3LPO and potentiality of EIS technique are discussed in the paper.

Recent case studies reported large scale disbondments of three-layer polyolefin (3-LPE) coatings, which could favour corrosion beneath the coating and lead to possible major damage. Therefore, it is necessary to better investigate the adhesion strength of fusion-bonded epoxy (FBE) primer to steel taking into account the water diffusing through the topcoat within the lifetime of pipeline. A methodology was developed to examine the adhesion of sublayers to steel under wet exposure: peel tests were carried out on pipe rings industrially coated with FBE and adhesive layers only, aged in vapour to simulate the water ingress through the topcoat. This methodology could be included in selection or pre-qualification tests. 1 BACKGROUND Among the two great families of external coatings of pipelines-FBE coatings and 3-LPE-each one has its advantages and disadvantages. In both cases, FBE is applied in direct contact to the freshly grit blasted pipe in order to provide good anchoring to steel.

We determine the complete set of nanofiltration (NF) parameters (rejection rate, electric filtration potential, volume flux density) of single salts using an analytical approach. Our model is based on the hindered extended Nernst−Planck (ENP) and Stokes equations. We solve the transport equations within the scope of the hindered electrotransport (HET) model, which takes into account ion charge and size (rejection is controlled by both electrostatic and steric effects). We also validate these calculations using both an analytical solution to the classic ENP model, which neglects the ion size, and numerical methods via our NF simulation program, Nanoflux. A preliminary application of the model to organic membranes suggests that the HET model provides a coherent description of ion transport in charged nanoporous membranes.

The results of a detailed experimental and theoretical study of the rejection of single salts and multi-electrolyte mixtures by a loose ceramic TiO 2 (SCT Membralox®) membrane at the borderline between ultra- and nanofiltration (NF) are compared with similar results obtained using a tighter organic nanofilter (NF200). Theoretical ion rejection predictions for multi-electrolyte solutions are obtained by solving numerically the hindered transport extended Nernst–Planck (ENP) ion flux equations using our computer simulation program, nanoflux , which incorporates electrostatic, steric, and hydrodynamic interactions and a new choice for ion size (bare crystal, or Pauling, radius). We find that, depending on the operating conditions, the looser ceramic nanofilter does not necessarily perform less well than the tighter organic one. We also examine how well the rejection of multi-electrolyte mixtures can be predicted by hindered electro-transport theory (HETT), using a database of single salt results, over a wide range of relative salt mole proportions and pH. Finally, we propose a combined experimental and theoretical method for characterizing, simulating, and optimizing the performance of charged nanofilters using the computer program nanoflux .

We present a comparative study of the filtration performance of one ceramic and two organic nanofilters. The results of a detailed experimental and theoretical investigation of the rejection of single salts (NaCl, NaNO3, and CaCl2) and multi-electrolyte mixtures (NaCl/CaCl2/HCl and NaNO3/NaCl/CaCl2) by a loose ceramic TiO2 nanofilter (Membralox SCT) are compared with similar results obtained using two organic nanofilters (Desal 5 and NF200). We modelion transport in nanoscale pores using a hybrid Hindered Electro-Transport Theory (HETT) that accounts for the charge and size of ions. Theoretical ion rejections for multi-electrolyte mixtures are obtained by solving numerically the Hindered Transport extended Nernst-Planck ion flux Eqs. using a computer simulation program, NanoFlux, that we have developed to simulate transport in the nanofiltration range. The ion rejection in binary and ternary mixtures is reasonably well predicted by the theory, over a wide range of pH and relative salt mole fraction, from the single salt results, using an appropriate weighting and interpolation scheme.

Placement of lipid residues in sanitary landfills are now prohibited by French legislation. The lipid residues used in this work were collected from a wastewater plant and restaurant traps. Aerobic degradation of these mixtures by a mixed population originated from an activated sludge was studied. First, the lipid matter underwent a saponification reaction, which solubilized partially and emulsified the substrate. An activated sludge was acclimated to saponified grease carbon source in a sequencing batch culture mode. Microbial activity was evaluated by the on line measurement of the CO2 production rate in the exit gas. At a feed concentration of 2 gHEM/1, the substrate degradation rate was measured as high as 1.6 gHEM/1 /h, the COD and HEM removals were 75% and 90%, respectively. Finally the average biomass yield was 0.3 gMLSS/gHEM.

Membre du Jury: PLUMMER, Christopher et GACOUGNOLLE, Jean Louis et VERDU, Jacques et PERRIN, Gilles et LAIARINANDRASANA, Lucien; Létude a pour but de caractériser lévolution du comportement du Polyamide 11 au cours dun vieillissement thermo-mécanique de type fluage, et sintéresse en particulier à la fissuration fragile lente à 90°C.En suivant lévolution de nombreux paramètres physico-chimiques, nous avons déterminé des conditions de vieillissement qui permettent dobtenir un matériau ayant des propriétés semblables à celles du matériau vieilli en service (transport de fluide).La thèse démontre que le vieillissement influe fortement sur le comportement à la fissuration en fluage, et que le mécanisme dendommagement (multi-crazing) observé sur les éprouvettes est similaire à celui observé in-situ. A partir des mécanismes observés, deux méthodes de détermination des durées de vie sont proposées. Dune part, à partir de courbes maîtresses présentées dans le cadre de la mécanique de la rupture en viscoplasticité avec utilisation du paramètre C*h, paramètre pertinent pour le PA11 à 90°C. Dautre part, à partir de critères locaux sur la base dune loi de comportement viscoplastique (modèle DDI). La pertinence de deux modèles dendommagement a été testée et discutée à partir dessais en mode mixte I+II.

Organic matter of urban wastewaters (WW) is modified all along the treatment units of a wastewater treatment plant (WWTP). A fraction of the organic matter systematically remains at the end of biological treatment, mainly aggregated in particulate form. It is thus classified as refractory organics, noticed XU. The “exogenous” origin (e.g. originated from the urban WW) or “endogenous” one (e.g. residues produced by the microbial processes) and the quantitative contribution of compounds accumulated into the XU fraction are difficult to identify. Limited bioaccessibility and/or inappropriate chemical characteristics can be suspected. However, the reasons of their non-biodegradability are not clearly identified that limits an optimal valorization of sewage sludge by anaerobic digestion (AD). Focusing specifically on the refractory COD fraction of sewage sludge, this research work attempts to define its origin, to quantify its proportion depending on the applied operating conditions in the WWTP and to characterize the physical and chemical properties of its different compounds.A first approach is carried out to analyze the relationship between the WWTP operating conditions and the biodegradability of various sludges. The scientific approach is based on (1) the use of sludges of contrasted composition (fed with raw wastewater, or pre-settled WW, diluted primary sludge or synthetic influent, and produced with a solid retention time in the range of 2 and 70 days), and, on (2) the comparative analysis of physical, biological and chemical characteristics for refractory matrices resulting from their ultimate anaerobic digestion. Refractory COD fractionations are estimated comparing experimental and ASM1 predicted data. While 85% of anaerobic refractory organic matter remain aggregated, two characterization approaches were applied: (i) direct analysis (on unmodified particulate matter) of the global chemical fingerprint by infrared spectroscopy (IR) on attenuated total reflexion (ATR); (ii) molecular analysis (fluorescence 2D and 3D, UV 210 and 280 nm, biochemical assays) of solubilized fractions obtained by thermo-chemical solubilisation of the refractory aggregate.Combined with statistical tools (Hierarchical Ascendant Classification, HAC and Principal Component Analysis, PCA), infrared fingerprints appear relevant to chemically discriminate refractory residues of the selected sludges and hence to follow the evolution of the chemistry of matrices along the treatments chains. Main factors involved in the chemical fingerprint of XU are highlighted. For example the major effect of the chemistry of exogenic refractory compounds (XU,inf) on the XU chemical fingerprint is shown. In addition, our work underlines the interest of using complementary analytical techniques to get a more accurate chemical characterization of the molecules involved in the ultimate refractory matrices. For example, a significant contribution of proteins and humics on the chemistry of refractory aggregate could be observed with a clear contribution of bacterial compounds to protein refractory fraction.Finally, the infrared fingerprint was used to characterize the effect of heat treatments (60-95°C) or chemical treatments (acid and alkaline hydrolysis) on the chemistry of XU. In perspective, this approach could be extended to other treatments (e.g. high temperature, ozonation, enzymatic hydrolysis) to assess their effects and to define their optimal operating point for degradation of refractory compounds. Furthermore, the possibility to discriminate chemical fingerprints of different refractory residues could also be exploited. Acquiring spectral data banks could better define the scope of application of treatment units combined with the anaerobic digestion of sewage sludge.; La matière des eaux usées urbaines (ERU) subit des transformations au sein des filières « eau » et « boue » des stations d’épuration (STEP). Une fraction de la matière organique est systématiquement retrouvée en fin de traitement biologique sous forme particulaire et est, à ce titre, identifiée comme non biodégradable et notée XU. L’origine « exogène » i.e. provenant de l’ERU brute, ou « endogène », i.e, résidus générés par les processus microbiens, et la contribution quantitative des composés accumulés dans cette fraction XU ne sont pas identifiables simplement. Par ailleurs, si une faible bioaccessibilité et/ou une inadéquation entre leur nature chimique et le pool enzymatique présent peuvent être suspectées, les raisons de leur caractère réfractaire sont mal connues et constituent un frein pour optimiser la valorisation de la boue par digestion anaérobie. S’intéressant spécifiquement à la fraction organique réfractaire d’une boue d’épuration, ce travail de thèse s’est donc attaché à définir son origine, à quantifier sa proportion selon différentes conditions opératoires de STEP et à caractériser ses composés d’un point de vue physique et chimique. Une approche filière a tout d’abord été menée pour analyser la relation entre l’origine et la biodégradabilité d’une boue. Deux approches de caractérisation chimique ont été mises en œuvre : (i) Analyse directe de l’empreinte chimique globale par spectrophotométrie infrarouge (IR) en réflexion totale atténuée (ATR) ; (ii) Analyses moléculaires (fluorescence 2D et 3D, UV 210 et 280 nm, dosages biochimiques) de fractions solubilisées après déconstruction thermo-chimique de l’agrégat réfractaire. Associée à des analyses statistiques, l’utilisation de l’empreinte IR s’est révélée pertinente pour différencier chimiquement différentes matrices réfractaires et suivre l’évolution des empreintes au fil des unités de traitement d’épuration. Par ailleurs, l’utilisation combinée de techniques analytiques complémentaires a permis une caractérisation plus précise des familles de molécules impliquées. Enfin, l’empreinte IR s’est avéré un outil pertinent de caractérisation de l’effet d’un traitement thermique (60 à 95°C) ou chimique (hydrolyse acide et alcaline) sur la chimie de la fraction XU