Olivier Potier

University of Lorraine | UdL · LRGP, Laboratoire Réactions et Génie des Procédés

Industrial cooling circuits with wet cooling towers use raw water to remove residual heat from industrial processes. These circuits are very prone to fouling and particularly biofouling. This work proposes a compartmental model built from a full hydrodynamic characterisation (using CFD and experimental; local and system data) of an industrial cooli...

The aim of this study is to develop a short cost-effective methodology for tracing the temporal and spatial anthropogenic inputs of micropollutants into ecosystems. The method involves a precise identification of the sampling sites based on various constraints: (1) one sampling site at each location to reduce the cost and the sampling time, (2) the...

This Scientific and Technical Report (STR) provides in-depth fundamentals and guidelines regarding Computational Fluid Dynamics (CFD) simulations of Water Resources Recovery Facilities (WRRFs) unit processes (e.g. headworks, aerobic and anaerobic biological reactors, settling tanks, disinfection). Each unit process is described with respect to: Lit...

This study aimed to investigate the effects of sludge retention time (SRT), hydraulic retention time (HRT), and biomass concentration (CTSS) in activated sludge systems on removal of various micropollutants (MPs), covering a wide spectrum of biodegradability. The influence of biomass concentration on the classical pseudo-first-order rate constant w...

This study aimed to investigate the effects of sludge retention time (SRT), hydraulic retention time (HRT), and biomass concentration (CTSS) in activated sludge systems on removal of various micropollutants (MPs), covering a wide spectrum of biodegradability. The influence of biomass concentration on the classical pseudo-first-order rate constant w...

Compartmental modelling is a hybrid way to model complex systems in Chemical Engineering. This modelling approach offers numerous advantages because it aggregates information from both local and system scale models. Compartmental models allow multi-scale modelling with low computational time compared to a full coupled model (e.g. reactive numerical...

The development of technologies capable of eliminating a wide spectrum of micropollutants of diverse nature from waters becomes essential. Advanced oxidation processes (AOPs) seem to be the most promising technologies but the most appropriate AOP to remove the micropollutants is still under debate. In this study, for the first time, the comparison...

In this paper, for the first time, faujasite Y zeolite impregnated with iron (III) was employed as a catalyst to remove a real cocktail of micropollutants inside real water samples from the Meurthe river by the means of the heterogeneous photo-Fenton process. The catalyst was prepared by the wet impregnation method using iron (III) nitrate nonahydr...

In this paper, CFD simulations are employed to characterize the effects of bubble aerator layouts (i.e. spatial arrangement) on the hydrodynamics in activated sludge reactors. The first configuration considered is a channel reactor with aerators placed alongside one lateral wall, for which velocity measurements are available in literature. CFD resu...

Our aim was to provide guidelines for restoring and enhancing the self-purification capacity of Mediterranean urban creeks (no summer flow), in particular their resilience to pollution induced by discharges of combined sewer overflows (CSO).

Antibiotics-bacteria interactions depend on antibiotic concentration at the scale of bacteria. This study investigates how vancomycin penetrates into activated sludge flocs and can be sorbed on the bacteria and extracellular polymeric substances (EPS). The 3D structure of flocs was imaged using EPS autofluorescence. The green fluorescent BODIPY® FL...

The use of Computational Fluid Dynamics (CFD) in the wastewater field has long been limited to troubleshooting of design flaws. Research-wise, this has recently opened up to the potential usage of CFD in the reactor design phase. Another noticeable shift is the one from only considering plain hydrodynamics to the coupling to kinetic models and popu...

The anaerobic codigestion of cow slurry with roadside grass was investigated in this study. Ensilage is known to enhance the anaerobic digestibility of grass, but the literature does not provide accurate information about the suitable silage duration needed to ensure effective codigestion. Grass was cut along roadsides and ensiled for different dur...

Some representations are well established in Chemical Engineering: the logic of unit operations, the logic linking reaction, transfer and transport phenomena or the logic of scales (from atoms to process and even to market). Today chemical and process engineers aim to open new opportunities for innovation, promote new ideas and create new represent...

Computational fluid dynamics (CFD) modelling in the wastewater treatment (WWT) field is continuing to grow and be used to solve increasingly complex problems. However, the future of CFD models and their value to the wastewater field are a function of their proper application and knowledge of their limits. As has been established for other types of...

Some representations are well established in Chemical Engineering: the logic of unit operations, the logic linking reaction, transfer and transport phenomena or the logic of scales (from atoms to process and even to market). Today chemical and process engineers aim to open new opportunities for innovation, promote new ideas and create new represent...

Modelling has been used frequently for both system understanding and optimization. However, the challenges put on the models are constantly growing. This entails new regulations for effluent, more accurate energy consumption predictions, predictions of greenhouse gas emissions, enlarging the scale towards urban water systems, to name but a few. Hen...

To date, computational fluid dynamics (CFD) models have been primarily used for evaluation of hydraulic problems at wastewater treatment plants (WWTPs). A potentially more powerful use, however, is to simulate integrated physical, chemical and/or biological processes involved in WWTP unit processes on a spatial scale and to use the gathered knowled...

Dans les écosystèmes aquatiques, l’oxygène dissous est consommé par les processus chimiques et biologiques de l’autoépuration (oxydoréduction, dégradation de la matière organique,...) ainsi que par la respiration des espèces aquatiques. L’autoépuration sera donc favorisée par une amélioration de l’aération et le taux d’oxygène dissous constituera u...

Stepped cascades are recognized as high potential air-water gas exchangers. In natural rivers, these structures enhance oxygen transfer to water by creating turbulence at interface with increasing air entrainment in water and air-water surface exchange. Stepped cascades could be really useful to improve the natural self-purification process by prov...

The efficiency of an in-line stormwater physic-chemical treatment system combining sand removal, flocculation-coagulation and subsequent settling has been assessed by simulation. Such a system is designed to both reduce the discharge of pollution during storm events in receiving water bodies and to avoid disturbances on the downstream wastewater tr...

Direct red 81 (DR 81) dye removal by electrocoagulation /flotation process using aluminum electrode was studied in a continuous electrochemical reactor. The designed reactor includes an electrochemical cell and a sludge separation cell. The effect of operating parameters such as current density and inlet flow rate (Q) on the dye, COD, suspended con...

Nowadays there exist two main approaches to simulate the hydrodynamics of chemical reactors: the systemic method, based on the description of a given reactor as a limited number of elementary reactors, and the more theoretical CFD approach, based on the resolution of the Navier–Stokes equations in a large number of computing cells. This work descri...

Definition of innovation Field of innovation in the chemical engineering industry The need for innovation Methods for innovation in chemical engineering industry Conclusion Bibliography

The tertiary treatment of paper mill wastewaters was investigated by testing the effect of batch electrocoagulation for 90min with two parallel iron or aluminum plates at two values of the current density (100 and 150A/m2). Dissolved organic carbon removal ranged between 24% and 46%, and chemical oxygen demand removal ranged between 32% and 68%. UV...

In order to characterize the pollution discharged into the Moselle River and some of its tributaries, spectroscopic techniques, namely UV-vis spectroscopy and synchronous fluorescence spectroscopy, have been combined. UV-visible spectra were analysed using the maximum of the second derivative at 225 nm (related to nitrates), the SUVA254 and E2/E3 i...

This paper presents an experimental and numerical study of an activated sludge channel pilot plant. Concentration profiles of oxygen, COD, NO(3) and NH(4) have been measured for several operating conditions. These profiles have been compared to the simulated ones with three different modelling approaches, namely a systemic approach, CFD and compart...

Rivers used for drinking water production might be subject to anthropogenic pollution discharge upstream of the intake point. This problem was investigated in the case of the Moselle River, used for water production in Nancy (350,000 inhabitants) and which might be impacted by industrial activities 60 km upstream. The arsenic flux of a pulp and pap...

The effect of erythromycin on activated sludge bacteria according to their Gram type was investigated with 3-dimensional Confocal Laser Scanning Microscopy (CLSM) time-lapse imaging. The fluorescent stains SYTOX Green and Texas Red-X conjugate of wheat germ agglutinin stained dying bacteria and Gram(+) bacteria respectively. Time-lapse imaging allo...

New regulations for wastewater treatment that will insure greater reliability of the wastewater treatment plants are being established, that is to say in the case of an activated sludge plant, a better control of the biological process. The use of biological sensors would appear to increase the reliability of the plants by allowing the assessment o...

The paper deals with the treatment of arsenic-containing industrial wastewaters by electrocoagulation. The waste issued from a paper mill industry downstream of the biological treatment by activated sludge was enriched with arsenic salts for the purpose of investigation of the treatment of mixed pollution. First, the treatment of single polluted wa...

This study investigates erythromycin toxicity toward activated sludge as a function of exposure time and antibiotic concentration. Batch experiments were conducted and microscopic techniques ranging from bright-field microscopy to epifluorescence and confocal laser scanning microscopy (CLSM), combined with a fluorescent viability indicator (BacLigh...

Electrocoagulation (EC) has been employed for the reduction of chemical oxygen demand (COD) of industrial wastewater in batch EC reactor using aluminium electrodes. Sedimentation step with different sludge settling velocities (SSV) followed the EC step which has been used for the removal of turbidity (NTU) and total sludge concentration (TS). The i...

Nowadays there exist two main approaches to simulate the hydrodynamics of chemical reactors: the systemic method, based on the description of a given reactor as a limited number of elementary reactors, and the more theoretical CFD approach, based on the resolution of the Navier–Stokes equations in a large number of computing cells. This work descri...

This study examines the effects of erythromycin on activated sludge from two French urban wastewater treatment plants (WWTPs). Wastewater spiked with 10 mg/L erythromycin inhibited the specific evolution rate of chemical oxygen demand (COD) by 79% (standard deviation 34%) and the specific N-NH4+ evolution rate by 41% (standard deviation 25%). A tem...

This paper deals with treatment of industrial wastewaters by electrocoagulation technique, with emphasis on settling process. The influence of electrode material, current density, pH, treatment period on the sludge settling characteristics has been investigated. The wastewater issued from textile industry is characterized by its high suspended soli...

The presence of antibiotics in water resources has been disturbing news for the stakeholders who are responsible for public health and the drinking water supply. In many cases, biological wastewater treatment plants are the final opportunity in the water cycle to trap these substances. The sensitivity of activated sludge bacteria to erythromycin, a...

This paper presents a complete CFD modelling of a wastewater gas–liquid cross-flow reactor, taking into account hydrodynamics, mass transfer and biological reactions. Transfer processes, kinetics model and assumptions made are described in detail. The simulations have been successfully compared to exper-imental results obtained in a bench scale rea...

A simplified dynamic model of a hybrid wastewater treatment plant which combines activated sludge+biofilm carriers in a fluidized bed has been developed, based on information collected on a full-scale plant. High nitrification yield can be achieved but denitrification requires a tight dosing of external carbon, for which a PI controller has been im...

Résumé Depuis quelques années, la présence de substances pharmaceutiques a été observée dans les milieux aquatiques y compris dans l’eau potable. Les principales sources de dispersion de ces composés dans l’environnement sont les stations d’épuration des eaux usées (STEP). Une analyse de la littérature publiée sur le sujet est proposée. Ce sont les...

Wastewater conductivity has been monitored for extended periods of time by in situ probes and on grabbed samples in four communities (from 1,000 to 350,000 PE). In parallel, the concentrations of the main ionic contributors, such as calcium, sodium, potassium, magnesium, ammonium, orthophosphate, chloride and sulphate have been measured and their v...

In order to compare whether sludge age control by wastage from the biological reactor is more efficient than wastage from the final clarifier in wastewater treatment plants by activated sludge, the Benchmark Simulation Model 1 has been modified. The secondary settler has been made reactive and the sludge settling characteristics vary as a function...

A three-dimensional Eulerian–Eulerian two-phase approach has been used for the simulation of a cross-flow gas–liquid wastewater treatment reactor. Two different turbulence models have been tested: the k–ε and Reynolds Stress Model (RSM) models. Bubble induced turbulence source terms have been added to these models. Numerical results have been valid...

Tracer studies have been widely applied to characterize the flow behavior in activated sludge reactors. The channel reactor with bottom aerators is one of the widespread designs in large wastewater treatment plants. Its flow behavior is well modeled either as a plug flow reactor with axial dispersion or as the perfect mixing cells in series. Severa...

For several years, the occurrence of pharmaceutical substances in the aquatic environment, and even in drinking water, has been a source of concern. The main sources of dispersion of these substances are wastewater treatment plants (WWTP). An analysis of the available literature on this topic is proposed. Analgesic, anti-inflammatory, anti-choleste...

Municipal wastewater samples have been collected in three different types of community and fingerprinted by optical methods combining UV-visible spectrometry, synchronous fluorescence spectrometry and turbidity. Correlations, whose slope depends on the sampling location, were obtained between absorbance at 254 nm and the synchronous fluorescence in...

Residence time distribution experiments have been performed on an activated sludge 3000 m3 channel reactor aerated by gas diffusion (for different liquid flowrates under constant aeration rate and constant water depth) and on a bench-scale channel reactor aerated from the bottom (for different liquid and gas flowrates and water depths) in order to...

Two methods based on adaptive principal components analysis (APCA) are compared to extract, from primary measurements, information related to the changes of wastewater characteristics induced by variable weather conditions and/or to the presence of toxic substances. The primary measurements are activated sludge respiratory data obtained by short-te...

A short-term batch respirometric test coupled with ultraviolet (UV) photometry was developed to detect the presence in waste water of toxic substances such as heavy metals, cleaning and sanitising agents, and textile dyes. Tests have been performed on a waste water plant containing various toxic substances in order to assess the usefulness of this...

Des méthodes optiques (spectroscopie UV-visible, spectroscopie de fluorescence synchrone) ont été employées pour analyser de façon rapide des eaux de provenances diverses (réservoir et lagune urbaine au Brésil, station de traitement biologique en France) susceptibles d'être polluées par des composés de nature anthropique. Des similitudes sont obser...

Estimation of wastewater composition (Chemical Organic Demand – COD and nitrogen-related species such as ammonia and organic nitrogen) for on-line control of treatment plants based on Principal Components Regression (PCR) and Partial Least Squares (PLS) applied to spectrometric data (turbidity, UV-visible and synchronous fluorescence spectra). Sati...

Classical culture media, as well as domestic and/or industrial wastewater treated by biological processes, have a complex composition. The on-line and/or in situ determination of some substances is possible, but expensive, as sample collection and pre-treatment are often necessary with strict rules of sterility. More global methods can be used to d...

The robustness of the control strategies developed in the COST 624 benchmark has been tested against the sophistication of the model describing the hydraulic behaviour of the biological reactor of a wastewater treatment plant by activated sludge. In such a large biological reactor of the channel type, hydrodynamics are intermediate between plug flo...

An adaptive principal component analysis applied to sets of data provided by global analytical methods (UV-visible spectra, buffer capacity curves, respirometric tests) is proposed as a generic procedure for on-line and fast characterization of wastewater. The data-mining procedure is able to deal with a large amount of information, takes into acco...

The robustness of the control strategies developed in the COST 624 benchmark have been tested against the sophistication of the model describing the hydraulic behaviour of the biological reactor of a wastewater treatment plant by activated sludge. In such a large biological reactor of the channel type, hydrodynamics are intermediate between plug fl...

Processes - The Residence-Time Distribution (RTD) is a chemical engineering concept introduced by Danckwerts in 1953. It has been described in a multitude of scientific papers and applied for various industrial processes. The development of Computer Fluid Dynamics will improve the comprehension and optimisation of such processes. However, this appr...

A method based on the examination of the trajectory in a Principal Components space of the characteristics of the Oxygen Uptake Rate (OUR) curve obtained in a respirometry test is proposed to improve the detection of faults in activated sludge wastewater treatment plants (WWTPs). Due to slow modifications of the trajectory in normal situations a co...

New regulations for wastewater treatment that will insure greater reliability of the wastewater treatment plants are being established, that is to say in the case of an activated sludge plant, a better control of the biological process. The use of biological sensors would appear to increase the reliability of the plants by allowing the assessment o...

The presence in a municipal effluent of a compound able to inhibit the micro-organisms of an activated sludge wastewater treatment plant can involve a long-lasting misoperation of this plant and, thus, compromise the conformity rate imposed by the new european regulations. Thanks to the information given by two sensors, a respirometer and a spectro...

A quality-discharge model (concentration of COD) is proposed for the real-time control of municipal wastewater influx to a treatment plant. Its originality not only lies in its simplicity but also in the fact that it takes into account the clear parasitical waters. Results show that the assessment of the COD is quite good, better in any way than th...

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A dedicated software has been developped for the dynamic simulation of a municipal wastewater treatment plant by activated sludge. The primary settler, the aeration tank of canal-type with air injection and the secondary settler are modelled. The biological reaction takes into account the solubility and the biodegradability of the pollution and the...

A dedicated software has been developped for the dynamic simulation of a municipal wastewater treatment plant by activated sludge. The primary settler, the aeration tank of canal-type with air injection and the secondary settler are modelled. The biological reaction takes into account the solubility and the biodegradability of the pollution and the...