Seine Aval Research Articles

Improving monitoring of dissolved organic matter from the wastewater treatment plant to the receiving environment: A new high-frequency in situ fluorescence sensor capable of analyzing 29 pairs of Ex/Em wavelengths

A high-frequency, in situ fluorescence probe, called Fluocopée®, has been developed in order to better monitor variations in both the quality and quantity of dissolved organic matter within various aquatic environments (e.g. wastewater, receiving environments) thanks to a wide choice of 29 measured Excitation/Emission wavelength pairs. This advance pave the way to new measurement possibilities in comparison with existing probes, which are usually only able to measure 1–4 fluorophores. The qualification tests of the Fluocopée® probe indicate a high level of accuracy for the measurements of tyrosine, tryptophan and humic acids solutions. Good repeatability and reproducibility are also observed. For the first time, this tool has been deployed in an urban watershed (Bougival, Seine River, downstream of Paris) and in the settled effluent from a wastewater treatment plant (Seine aval, Achères, France). This new high-frequency in situ probe offers great application potential, including organic matter quality and quantity monitoring at drinking and wastewater treatment plants (treatment optimization) and in continental and marine waters (the fate of organic matter in biogeochemical cycles).

Optimization of the Paris wastewater treatment plants and sewer network: preliminary results

This paper deals with the application of second order come convex optimization to the real time management of the wastewater treatment plants and sewer network of Paris and of its suburbs. It presents preliminary results applied on a simple case study composed of (simple) validated models of three wastewater treatment plants (Seine Aval (SAV), Seine Centre (SEC) and Seine Grésillons (SEG)) and their (inter)connections to the sewer network modelled by transport delays.

Tracking the formation potential of vivianite within the treatment train of full-scale wastewater treatment plants

Phosphorus recovery is a vital element for the circular economy. Wastewater, especially sewage sludge, shows great potential for recovering phosphate in the form of vivianite. This work focuses on studying the iron, phosphorus, and sulfur interactions at full-scale wastewater treatment plants (Viikinmäki, Finland and Seine Aval, France) with the goal of identifying unit processes with a potential for vivianite formation. Concentrations of iron(III) and iron(II), phosphorus, and sulfur were used to evaluate the reduction of iron and the formation potential of vivianite. Mössbauer spectroscopy and X-ray diffraction (XRD) analysis were used to confirm the presence of vivianite in various locations on sludge lines. The results show that the vivianite formation potential increases as the molar Fe:P ratio increases, the anaerobic sludge retention time increases, and the sulfate concentration decreases. The digester is a prominent location for vivianite recovery, but not the only one. This work gives valuable insights into the dynamic interrelations of iron, phosphorus, and sulfur in full-scale conditions. These results will support the understanding of vivianite formation and pave the way for an alternative solution for vivianite recovery for example in plants that do not have an anaerobic digester.

Considering the plug-flow behavior of the gas phase in nitrifying BAF models significantly improves the prediction of N2O emissions

Nitrifying biologically active filters (BAFs) have been found to be high emitters of nitrous oxide (N2O), a powerful greenhouse gas contributing to ozone layer depletion. While recent models have greatly improved our understanding of the triggers of N2O emissions from suspended-growth processes, less is known about N2O emissions from full-scale biofilm processes.Tertiary nitrifying BAFs have been modeled at some occasions but considering strong simplifications on the description of gas-liquid exchanges which are not appropriate for N2O prediction. In this work, a tertiary nitrifying BAF model including the main N2O biological pathways was developed and confronted to full-scale data from Seine Aval, the largest wastewater resource recovery facility in Europe. A mass balance on the gaseous compounds was included in order to correctly describe the N2O gas-liquid partition, thus N2O emissions. Preliminary modifications of the model structure were made to include the gas phase as a compartment of the model, which significantly affected the prediction of nitrification. In particular, considering gas hold-up influenced the prediction of the hydraulic retention time, thus nitrification performances: a 3.5% gas fraction reduced ammonium removal by 13%, as the liquid volume, small in such systems, is highly sensitive to the gas presence. Finally, the value of the volumetric oxygen transfer coefficient was adjusted to successfully predict both nitrification and N2O emissions.

Implementation of a New Protocol of Odour Field Investigations for the Paris Wastewater Treatment Plants

In the 90’s, the wastewater management authority for the Paris area (‘Syndicat interdepartemental pour l'assainissement de l'agglomeration parisienne’ - SIAAP) established various odour survey tools in order to understand the link between odours and significant operating events at its Waste Water Treatment Plant (WWTP) and in the sewage network. These tools include monitoring stations (weather stations, sulphur compounds analysed with stationary and mobile analytical instruments), human observers (daily odour patrols, voluntary citizens’ panels and citizens’ complaints logbook), and air dispersion modelling (three-dimensional numerical CFD (Computational Fluid Dynamics) dispersion allowing real-time and forecast odour dispersion).Starting in 2017, some important changes were initiated in order to improve this monitoring system. Indeed, as a response to important redesign works of one of their WWTPs (Seine Aval), the SIAAP needed to demonstrate a monitoring tool with a high level of confidence, especially during the crucial commissioning period.Because the previously operated daily patrols showed some limitations, one of the first steps was to implement a new protocol for field investigations and data treatment. The chosen method is, for the most part, inspired by the new standards: EN 16841-1 and EN 16841-2 - Determination of odour in ambient air by using field inspection - Grid method and Plume method. The originality of the new protocol implemented by SIAAP lies in the fact that both methods – Grid method and Plume method – are merged and adapted to needs and means of the SIAAP, in order to collect relevant data.

Who Really Wants an Ambitious Large-Scale Restoration of the Seine Estuary? A Strategic Analysis of a Science–Policy Interface Locked in a Stalemate

The development of ecosystem knowledge is an essential condition for effective environmental management but using available knowledge to solve environmental controversies is still difficult in "real" situations. This paper explores the conditions under which ecological knowledge could contribute to the environmental strategies and actions of stakeholders at science-policy interface. Ecological restoration of the Seine estuary is an example of an environmental issue whose overall management has run into difficulties despite the production of a large amount of knowledge by a dedicated organization, GIP Seine Aval. Thanks to an action-research project, based on a futures study, we analyze the reasons of these difficulties and help the GIP Seine Aval adopt a robust strategy to overcome them. According to our results, most local stakeholders involved in the large-scale restoration project emphasize the need for a clear divide between knowledge production and environmental action. This kind of divide may be strategic in a context where the robustness of environmental decisions is strongly depending on the mobilization of "neutral" scientific knowledge. But in our case study, this rather blocks action because some powerful stakeholders continuously ask for more knowledge before taking action. The construction and analysis of possible future scenarios has led to three alternative strategies being identified to counter this stalemate situation: (1) to circumvent difficulties by creating indirect links between knowledge and actions; (2) to use knowledge to sustain advocacy for the interests of each and every stakeholder; (3) to involve citizens in decisions about knowledge production and use, so that environmental issues weight more on the local political agenda.

A simple model of wastewater treatment plants for managing the quality of the Seine River

The aim of this paper is to introduce a simple model for wastewater treatment plants that can be used for evaluating control strategies on the basin of the Seine River under different scenarios. The model represents a bioreactor without oxygen limitation. The construction of the model was based on the ASM1 with only one microbial population. The performance of the model was tested on daily data for a four year period over the three main wastewater treatment plants of the Seine River in Paris (Seine Aval, Seine Centre, and Seine Grésillons). Results demonstrated that the model was effective for predicting the concentrations of ammonia, nitrites, nitrates, biological oxygen demand, and total suspended solids. The developed model was found to be parsimonious and it can thus provide a useful tool in optimizing river quality once coupled to control strategies.

Long trend reduction of phosphorus wastewater loading in the Seine: determination of phosphorus speciation and sorption for modeling algal growth.

The lower Seine River is severely affected by the release of the treated wastewater from the 12 million inhabitants of the Paris agglomeration. Whereas urban effluents were the major source of phosphorus pollution in the late 1980s, the ban on polyphosphates from detergents in 1991 considerably reduced the phosphorus (P) loading to the Seine River and was followed in 2000 by the implementation of phosphorus treatment in the largest wastewater treatment plant of Paris conurbation (Seine Aval). Phosphorus discharged to the rivers from domestic wastewater was reduced by 80%, significantly decreasing phytoplankton biomass in the large branches of the Seine River. Considering that phosphorus treatment (the use of ferric salts in the P treatment line) might change the adsorption of ortho-phosphates on suspended matter, we experimentally studied again their sorption processes in these new conditions. We found parameters of the Langmuir equation (Pac=0.003mgPmgSS-1; Kps=0.04mgPL-1) that significantly differed from the values previously considered for modeling of the whole Seine, especially for Kps (Pac=0.0055mgPmgSS-1; Kps=0.7mgPL-1). Using the Seneque-Rivertrahler modeling approach, we showed a better agreement between P observations and simulations with the new P sorption parameters, with slight effect on the simulation of the development of phytoplankton in the water column.

Modelling the fate of nonylphenolic compounds in the Seine River — part 2: Assessing the impact of global change on daily concentrations

This study aims at modelling the daily concentrations of nonylphenolic compounds such as 4-nonylphenol (4-NP), nonylphenol monoethoxylate (NP1EO) and nonylphenoxy acetic acid (NP1EC) within the Seine River downstream of Paris City for over a year, firstly in the present state (year 2010) and for years 2050 and 2100 in order to assess the consequences of global change on the fate of nonylphenolic compounds in the Seine river.Concentrations were first simulated for the year 2010 and compared to monthly measured values downstream of Paris. To achieve this goal, the hydrodynamic and biogeochemical model, ProSe, was updated to simulate the fate of 4-NP, NP1EO and NP1EC. The Seine upstream and Oise River (tributaries of the Seine River) concentrations are estimated according to concentrations–flow relationships. For Seine Aval wastewater treatment plant (SA-WWTP), the concentrations are considered constant and the median values of 11 campaigns are used. The biodegradation kinetics of 4-NP, NP1EO and NP1EC in the Seine River were deduced from the results of the companion paper. The Nash–Sutcliffe coefficient indicates a good efficiency to simulate the concentrations of 4-NP, NP1EC and NP1EO over an entire year.Eight scenarios were built to forecast the impacts of global warming (flow decrease), population growth (SA-WWTP flow increase) and optimisation of wastewater treatment (improvement of the quality of effluents) on annual concentrations of 4-NP, NP1EO and NP1EC at Meulan by 2050 and 2100. As a result, global warming and population growth may increase the concentrations of 4-NP, NP1EC and NP1EO, especially during low-flow conditions, while the optimisation of wastewater treatment is an efficient solution to balance the global change by reducing WWTP outflows.

Treatment of combined sewer overflows by ballasted flocculation: Removal study of a large broad spectrum of pollutants

This study aims at examining the performance of the ballasted flocculation unit (BFU) on treating combined sewer overflows (CSOs) and the evaluation depends on the values obtained of routine wastewater parameters and on the contents of a large broad spectrum of pollutants. Accordingly, the full-scale BFU at the largest wastewater treatment plant in Europe (Seine Aval plant near Paris, France) is investigated during three sampling campaigns. Of the 97 molecules targeted, 57 substances including 18 priority substances and 11 priority hazardous substances were detected in the BFU influents confirming that wet weather flow (WWF) treatment has definitively proven to be necessary. The WWF treatment by ballasted flocculation appears as a promising but not a fully adapted technology for use in densely urbanized areas to considerably mitigate the CSO impacts. On operating at the optimal chemical and sand doses, this process appears to be a suitable technology to remove particles, carbonaceous and phosphorous pollutants, particulate metals and most of hydrophobic organic compounds whilst nitrogenous pollutants and most of hydrophilic compounds are from poorly (<20%) to moderately (<50%) removed. The BFU appeared less sensitive to the influent concentration fluctuations and hydraulic peak load (at the scale of the campaigns considered) than to the adjustments of chemical doses and sand injection. Investigating the performance of such process, could serve to develop management strategies that enable mitigating the impacts of CSOs on receiving water in compliance with the Water Framework Directive objectives.

Real-time management of odour on water treatment plant using a 3D simulation tool coupled to on-site sensors

In order to forecast and to follow the dispersion of odours around its treatment sites, SIAAP which treats wastewater for the entire region around Paris, developed and implemented an innovative tool called SYPROS. SYPROS is based on the 3D CFD dispersion tool Fluidyn-PANEIA and uses a Lagrangian puff model for real time calculations, together with a source definition module for determining the source emission rates in real time. In order to adjust the source emission the so-called remapping process has been implemented. A case study for the implementation of the comprehensive tool SYPROS on the Seine Aval site is described.

A report card and quality indicators for the Seine estuary: From scientific approach to operational tool

The scientific teams from the interdisciplinary Seine-Aval (SA) research program and the SA’s operational pole, GIPSA ( Groupement d’Intérêt Public Seine-Aval) have worked together to create a report card designed to help the Estuary Council ( Conseil de l’Estuaire) revitalize its original functions: maintaining functional links between the various estuarine ecosystems, comprehending and managing the estuary’s natural habitats and biological populations, and monitoring and improving the physical–chemical quality of the estuarine waters. The report card will be able to synthesize the information obtained from several system performance variables and available operational indicators. This approach, intended to guide the estuary managers, is the oeuvre of several scientific teams; it is particularly important in the context of the Water Framework Directive because it facilitates the elaboration of a group of relevant indicators, which can then be used as operational tools. A report card will provide decision-makers (e.g., political authorities; national, regional and local institutions and industries) with the key indicators for evaluating the system and predicting changes in terms of selected objectives, such as the preservation and restoration of the estuary’s environmental functionalities. The final objective of the research is to choose among the available indicators to approximate potential ecological risks. Integrating the socio-economical data will perhaps lead to setting risk acceptability thresholds for the different uses of the Seine estuary. In the end, collaboration between the scientists, the managers, and the GIPSA operational pole will be essential to produce a viable report card about the environmental status of the Seine estuary. To illustrate the research now under way, this article presents the results for three actions undertaken, concerning: (i) physical indicators (i.e., an inventory of the estuary first as a whole, and then section by section); (ii) benthic indicators (i.e., seven indices which show a moderate EcoQ for the lower part of the estuary); and (iii) a eutrophication indicator (i.e., an indicator for coastal eutrophication potential (ICEP), which helps to limit the nutrient fluxes (N or P) that exceed the silica flux delivered by the Seine network, based on the Redfield ratios for algal propagation).

Modeling the carbon cycle in the turbidity maximum of the Seine estuary

Estuaries are characterised by long residence time (CIFFROY et al. 2003, ), accumulation of high amounts of suspended matter (SM) in the turbidity maximum zone. They receives the waters of the whole drainage basin before transfer to the coastal and oceanic domains. Thus the question of the role of the estuaries for transformation, production and exportation of nutrients and organic matter was regularly renewed (DAY et al. 1989, ) and, given the complexity of estuaries and contexts, remains largely discussed (ABRIL et al. 2002, ). Given the difference between dissolved and particulate species transport, particulate organic matter fate is essentially under concern (KNOX 1986, ). This question was studied in the framework of SEINE AVAL, research program dedicated to the Seine estuary. In order to determine the relative importance of the sources of POC in the estuary and to interpret the high organic carbon (POC) content of the suspended matter (SM) in the turbidity maximum (up to 5 %) (ABRIL et al. 2002, ), a modelling of the carbon cycle was undertaken, based on in situ and laboratory measurements.

Paradox of estuarine quality: Benthic indicators and indices, consensus or debate for the future

The European Water Framework Directive will have instituted the concept of Ecological Quality Status (EQS) as a way to assess the biological quality of water masses. The EQS will be based mainly upon the composition of the different biological compartments in the ecosystem specially the benthos as compared to certain reference sites. Such management tools are already well established for freshwater (i.e. biotic indices), but not for coastal and estuarine (i.e. transitional) waters. In the framework of the Seine-Aval programme a workshop on benthic indicators was organized at Wimereux (France) in June 2005. The aim of this workshop and this paper is (1) to present the experiences of the Seine Aval researchers, and the French scientific approaches to benthic indicators, with those international experiences and approaches that have been published or are under development; and (2) to examine the existing benthic tools and their possible use in the characterization of the state of estuarine ecosystems. The debate during the workshop and the numerous recently published on the WFD are discussed in term of the implementation of the WFD in transitional water bodies using benthic indicators and indices. Some proposals for the future underline the needs to re-examine and adapt the different index thresholds, to take into account physical disturbances, to inventory the existing conditions vs reference conditions and to be as pragmatic as possible in using the WFD in transitional waters.

The spatial and temporal trends of Cd, Cu, Hg, Pb and Zn in Seine River floodplain deposits (1994–2000)

Fresh floodplain deposits (FD), from 11 key stations, covering the Seine mainstem and its major tributaries (Yonne, Marne and Oise Rivers), were sampled from 1994 to 2000. Background levels for Cd, Cu, Hg, Pb, and Zn were established using prehistoric FD and actual bed sediments collected in small forested sub-basins in the most upstream part of the basin. Throughout the Seine River Basin, FD contain elevated concentrations of Cd, Cu, Hg, Pb and Zn compared to local background values (by factors > twofold). In the Seine River Basin, trace element concentrations display substantial downstream increases as a result of increasing population densities, particularly from Greater Paris (10 million inhabitants), and reach their maxima at the river mouth (Poses). These elevated levels make the Seine one of the most heavily impacted rivers in the world. On the other hand, floodplain-associated trace element levels have declined over the past 7 years. This mirrors results from contemporaneous suspended sediment surveys at the river mouth for the 1984–1999 period. Most of these temporal declines appear to reflect reductions in industrial and domestic solid wastes discharged from the main Parisian sewage plant (Seine Aval).

Polycyclic aromatic hydrocarbons and polychlorobiphenyls in wastewaters and sewage sludges from the Paris area (France)

Polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs) were investigated during 1999–2000 in the sewerage system to the Seine Aval treatment plant which drains the Paris area (France). Contamination of sludges from storage chambers indicated a local origin typical of motor car traffic with PAH concentrations ( Σ16) ranging from 14 to 31 mg kg −1 of dry weight, pyrene/fluoranthene ratios ranging between 1.12 and 1.48 and PCB concentrations ( Σ7) ranging from 0.07 to 0.65 mg kg −1 of dry weight. In the same way, sludges from sand removal tanks displayed PAH values related to the importance of traffic whereas PCBs were rather characteristic of a diffuse origin. Among the five sewers entering the Seine Aval treatment plant, Clichy Argenteuil, which drains a large industrial area, was the most polluted one (PAHs as Σ3, 10 kg year −1; PCBs as Σ7, 3.5 kg year −1). Seasonal variations were observed for PAHs with higher levels in winter in relation with the occurrence of combustion processes. Ninety-eight percent of the PAHs and 76% of the PCBs were extracted during the treatment plant processes, the primary clarifier of which retained 50% of the pollutants. Fluoranthene and PCB concentrations in the final dehydrated sludge (mean values) were 1.07 and 0.623 mg kg −1 of dry weight, respectively. For PCBs, a significant correlation was found ( r=0.668, P<0.001) between wastewater and dehydrated sludge concentrations. Yearly measured amounts of PAHs ( Σ3) were twice higher in sludges (76.3 kg) than in precipitations (37.7 kg) whereas those of PCBs ( Σ7) brought by total atmospheric fallout (17.6 kg) and sludges (21.1 kg) did not differ significantly.

Sources et caractéristiques des composés phénoliques dans l’estuaire de la Seine

Sources and characteristics of phenolic compounds in the Seine estuary (France). Within the framework of the multi-disciplinary program Seine Aval, phenolic compounds obtained by CuO oxidation have been studied since 1995. Quantitative analyses have shown a terrestrial contribution in flood, characterized by compounds of the group P (polyols + phenol), S (syringic) and H (hydroxybenzoic). During the low water period, phenolic compounds allow a clear distinction between fluvial and estuarine suspended material. Fluvial run-off contained Syringic, Hydroxybenzoic and Vanillic phenols. In contrast, upstream penetrating marine and estuarine waters are characterized by cinnamic phenols originating from estuarine herbus. In the turbidity maximum zone, aerobic degradation of lignin material increases the (vanillic acid/vanillin) ratio. © 2000 Ifremer / CNRS / IRD / Éditions scientifiques et médicales Elsevier SAS Phenolic compounds / HPLC / suspended matter / Seine

Tertiary nitrification in an up flow biofilter on floating media: influence of temperature and COD load

The wastewater plant Seine Aval (located in Acheres, France) treats 6 million PE (25 m3/s average flow, 570 MGD) with activated sludge. Following a research program called “Azote Acheres” which demonstrated that biofilters are an economical solution, the Paris Metropolitan Area Sewage Service (SIAPP) has tested 3 industrial prototypes during a period of more than 4 years. One of these is an up-flow biofilter using a floating filter bed made of expanded polystyrene beads. This specific process is called BIOSTYR and is used here as a nitrifying tertiary biofilter. The purpose of this paper is to show that the biofilter process achieves very low, steady state, effluent ammonia concentrations with different applied nitrogen loads (0.3 to 2.7 kg NTK/m3.d), even with low temperature and high applied carbonaceous load. During this 4 years period, a model has been developed to explain the hydraulic behavior of the filter. By measuring the operating conditions (temperature, loads), the head loss of the filter can be predicted. After this test period, the prototype has been operated by Seine Aval plant staff. The results obtained have confirmed the previous test results.

A keypoint of nitrification in an upflow biofiltration reactor

The wastewater treatment plant Seine Aval at Achères is the largest plant in France, with an average flowrate of 25 m3/s. For the moment, this plant consists of an activated sludge process for organic carbon removal. However, due to the recent European water regulations, it will soon be necessary to remove nitrogen pollution. For this reason, tertiary nitrification prototype reactors were installed and tested, in order to examine a future upgrading of the plant. This article presents the results obtained, during the last two years, with an upflow BAF reactor utilizing a granular media with a density &amp;gt; 1. The objective will be to examine a key parameter of the process: the water velocity (part of the applied loading rate. The removal rate depends directly and linearly on the applied loading rate, as long as the nitrification conditions (aeration, temperature, etc …) are not limiting. The highest loading rates for nitrification, as well as for BOD5 removal and SS retention, were obtained at high water velocity (10 m3/m2.h). These results demonstrate that the hydraulic retention time, even when extremely short (10 minutes), does not influence the reactor performance. The high water velocities in this kind of filter positively influence and improve the mass transfer between the liquid environment and the bacteria.

A keypoint of nitrification in an upflow biofiltration reactor

The wastewater treatment plant Seine Aval at Achères is the largest plant in France, with an average flowrate of 23 m3/s. For the moment, this plant consists of an activated sludge process for organic carbon removal. However, due to the recent European water regulations, it will soon be necessary to remove nitrogen pollution. For this reason, tertiary nitrification prototype reactors were installed and tested, in order to examine a future upgrading of the plant. This article presents the results obtained, during the last two years, with an upflow BAF reactor utilizing a granular media with a density > 1. The objective will be to examine a key parameter of the process: the water velocity (part of the applied loading rate. The removal rate depends directly and linearly on the applied loading rate, as long as the nitrification conditions (aeration, temperature, etc …) are not limiting. The highest loading rates for nitrification, as well as for BOD5 removal and SS retention, were obtained at high water velocity (10 m3/m2.h). These results demonstrate that the hydraulic retention time, even when extremely short (10 minutes), does not influence the reactor performance. The high water velocities in this kind of filter positively influence and improve the mass transfer between the liquid environment and the bacteria.