Comparison of Parameters Characterizing Organic Matter in a Combined Sewer during Rainfall Events and Dry Weather

To understand the effect of combined sewer overflows on the river Seine (France), a characterization of effluent in terms of organic matter and bacterial biomass was carried out during several sampling campaigns performed in a combined sewer located in Parisian suburbs under wet and dry weather conditions. Measurements classically used to study wastewater (suspended matter, chemical oxygen demand [COD] and biochemical oxygen demand [BOD]) were compared with the estimate of biodegradable and refractory fractions of particulate and dissolved organic carbon. Relationships among different parameters used to describe organic material in effluent were established. Even for large fluctuations in organic matter concentrations, highly homogeneous ratios between the different descriptors during wet and dry weather were observed, and no significant differences could be observed in two catchments strongly differing by their sizes. The only two small differences in relative composition that could be observed between dry and wet weather were slightly lower content of organic carbon in suspended solids and a lower biodegradability of this material during rain events. Accordingly, with the help of obtained relationships and values of classical variables like turbidity, BOD, and COD for a given effluent, it is possible to make reasonably accurate estimates of its composition in terms of biodegradable and refractory fractions of dissolved and particulate organic matter and bacterial biomass.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Organic matter transport and degradation in the river Seine (France) after a combined sewer overflow

The impact of a combined sewer overflow (CSO) upon receiving waters has been studied in the river Seine during Summers 1995 and 1996. Three main events have been monitored with special attention paid to the computation of oxygen, carbon and suspended solids budgets. Bacterial biomass and bacterial production rates have been measured to provide a more accurate understanding of the carbon cycle of the river Seine. Oxygen consumption inside the polluted water masses was totally due to the activity of large bacteria discharged into the river by the CSO, the activity of native small bacteria did not significantly increase after CSOs. Suspended solids issued from the CSO very quickly settles in this deep, slowly flowing river. However, discharged dissolved organic carbon (DOC) cannot account for the observed oxygen depletions, the additional carbon source could be phytoplankton or deflocculated/degraded particulate organic matter.info:eu-repo/semantics/publishe

Use of High Frequency measurements to better determine the concentration-flow relationship (CQ) of the Avenelles watershed (ORGEVAL Critical Zone Observatory).

International audienceThe Water Framework Directive (DCE 2000/) shows an ambition to regain the good ecological status of water bodies. In France, two types of water quality indicators are currently evaluated: annual concentrations (arithmetic mean, median, upper quantile, flow-weighted averages) that are reported in a quality grid (SEQ -Water) and the annual flows generally brought back to the surface of the producing catchment area. However, it is now known that point measurements do not make it possible to apprehend the phenomena of dilution and leaching, and considerably bias the evaluation of the chemical quality of the environment. With the application of high frequency measurements, these shortcomings can be solved, since taking measures continuously, we can better understand the relationship of the interactions of chemical concentrations with water (flow), in order to help us to obtain valuable information for the assessment of the state of water bodies, the quantitative and qualitative preservation of water resources and superficial aquatic environments in the Critical Zone. Also it could provide useful guidance for the continuation of programs for the restoration of aquatic environments and the identification of vulnerable areas. This sub-hourly high-frequency measurements (30 min) were taken from the River Lab station [1] set up in the outlet of the Avenelles River(ORGEVAL CZO, 70 km Est of Paris). The series of data carried out from June 2015 to August 2016 (i.e. 22,000 measurements over 14 months), being more than one hydrological year in which we find the different rainy events from the low to the flood season. It should be noted that these series also contain recordings made during the exceptional flood of May-June 2016

Assainir la banlieue de Paris :des fosses septiques au tout-à-l’égout, quels effets sur la qualité de l’eau de la Seine ?

info:eu-repo/semantics/publishe

Use of High Frequency measurements to better determine the concentration-flow relationship (CQ) of the Avenelles watershed (ORGEVAL Critical Zone Observatory).

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Gestion intégrée de la ressource et des infrastructuresInternational audienceThe Water Framework Directive (DCE 2000/) shows an ambition to regain the good ecological status of water bodies. In France, two types of water quality indicators are currently evaluated: annual concentrations (arithmetic mean, median, upper quantile, flow-weighted averages) that are reported in a quality grid (SEQ -Water) and the annual flows generally brought back to the surface of the producing catchment area. However, it is now known that point measurements do not make it possible to apprehend the phenomena of dilution and leaching, and considerably bias the evaluation of the chemical quality of the environment. With the application of high frequency measurements, these shortcomings can be solved, since taking measures continuously, we can better understand the relationship of the interactions of chemical concentrations with water (flow), in order to help us to obtain valuable information for the assessment of the state of water bodies, the quantitative and qualitative preservation of water resources and superficial aquatic environments in the Critical Zone. Also it could provide useful guidance for the continuation of programs for the restoration of aquatic environments and the identification of vulnerable areas. This sub-hourly high-frequency measurements (30 min) were taken from the River Lab station [1] set up in the outlet of the Avenelles River(ORGEVAL CZO, 70 km Est of Paris). The series of data carried out from June 2015 to August 2016 (i.e. 22,000 measurements over 14 months), being more than one hydrological year in which we find the different rainy events from the low to the flood season. It should be noted that these series also contain recordings made during the exceptional flood of May-June 2016

Polymeric membrane as passive sampler : a new simple calibration protocol

International audienc

What does Semipermeable Membrane Device (SPMD) sampling mean? accuracy of time-weighted average concentration estimations of truly dissolved compounds

International audienceSPMDs1 are commonly used integrative passive samplers for hydrophobic organic compounds in water. Two major assumptions drive the interpretation of accumulated amounts of contaminants: Because of steric hindrance in the polyethylene membrane, only a fraction of dissolved organic compounds in water may be accumulated. - 1st assumption : only truly dissolved compounds are SPMD-available From the accumulated amount of a substance in SPMD, and dissipation of Performance Reference Compounds, the concentration of SPMD-available substance in water can be estimated. - 2nd assumption : the estimated SPMD-available concentration is a time-weighted average (TWA) concentration. Compiling field studies (sampling campaigns in rivers2 and wastewater treatment plants3) and using numerical simulations, we investigated the validity of these two assumption

What does Semi-Permeable membrane device (SPMD) sampling mean? an insight on the "time-weight integrative" and "SPMD-availability" hypothesis

International audienceSPMDs are commonly used integrative passive samplers for hydrophobic organic compounds [1]. Because of steric hindrance in the polyethylene membrane, only a fraction of dissolved organic compounds in water may be accumulated. It is usually assumed that only truly dissolved compounds are available to SPMD. From the accumulated amount of a substance in SPMD, and dissipation of Performance Reference Compounds, the exchange rate constant and the concentration of SPMD-available substance in water can be estimated. It is usually assumed that the SPMD-available concentration estimated from accumulation in SPMD corresponds to the time-weight average (TWA) concentration. Moreover, provided that the half-time is higher than the exposure duration, the sampling is supposed to be fully integrative. In this study, we investigate the significance of the "time-weight" integrative sampling: factors such as deployment duration, exchange rate constants, but also water concentration variations are examined. The chemical form of SPMD-available compounds is also investigated: compiling several field studies, SPMDavailable concentrations are compared to total dissolved concentrations of Polycyclic Aromatic Hydrocarbons (PAHs). Assuming that PAHs that are bond to dissolved organic matter cannot enter the membrane of SPMD, in situ partitioning coefficients KDOC are computed and compared to lab data