Long-term performances and membrane lifespan of full-scale MBR treating filtrate from sludge ultra-dewatering.

An MBR treating filtrate from sludge ultra-dewatering (FSD) was studied to evaluate the real applicability to concentrated effluents. The MBR operation is comparable to conventional wastewater MBRs in terms of F/M and nitrogen to sludge ratios, SRT and MLSS in biological tanks. On the contrary, the volume treated is lower with a comparable pollution load, the effluent being concentrated in nitrogen and carbon. Very high and stable ammonium (97.7 ± 2.4%), total phosphorus (81.8 ± 11.9%), chemical (89.5 ± 2.3%) and biochemical oxygen demands (98.8 ± 0.7%) removals are observed despite a significant modification of the FSD composition. The MBR removal performances are whether comparable or greater than those reported at full-scale for Sharon or Anammox processes. The evolution of membranes properties, in particular, the decrease of permeability induced by the irreversible fouling, leads to a decrease of the daily permeate volume produced and an increase of the chemical cleaning need. The membrane lifespan was determined to be 5.5 years based on both the permeability loss and TSS in permeate. The permeability is directly correlated to the cumulated filtered flux of colloidal matter and a total of 350 kg O2/m2 of the membrane (COD in the supernatant) is needed to reach a permeability below 100 LMH/bar. The specific energy consumption is comparable to other wastewater MBRs in kWh/kgCOD removed but the intensive chemical cleanings need to be 2.5-4.5 times more frequent. Overall, it can be concluded that MBR is adapted to treat FSD efficiently.

A POLD3/BLM dependent pathway handles DSBs in transcribed chromatin upon excessive RNA:DNA hybrid accumulation.

Transcriptionally active loci are particularly prone to breakage and mounting evidence suggests that DNA Double-Strand Breaks arising in active genes are handled by a dedicated repair pathway, Transcription-Coupled DSB Repair (TC-DSBR), that entails R-loop accumulation and dissolution. Here, we uncover a function for the Bloom RecQ DNA helicase (BLM) in TC-DSBR in human cells. BLM is recruited in a transcription dependent-manner at DSBs where it fosters resection, RAD51 binding and accurate Homologous Recombination repair. However, in an R-loop dissolution-deficient background, we find that BLM promotes cell death. We report that upon excessive RNA:DNA hybrid accumulation, DNA synthesis is enhanced at DSBs, in a manner that depends on BLM and POLD3. Altogether our work unveils a role for BLM at DSBs in active chromatin, and highlights the toxic potential of RNA:DNA hybrids that accumulate at transcription-associated DSBs.

Fate of emerging and priority micropollutants during the sewage sludge treatment - Part 2: Mass balances of organic contaminants on sludge treatments are challenging.

This paper analyzes the fate of 71 priority and emerging organic contaminants all along the treatment trains of sewage sludge treatment facilities in Paris including dewatering by centrifugation, thermal drying and anaerobic digestion. It aimed at proposing and applying a mass balances calculation methodology to each process and pollutant. This data validation strategy demonstrated the complexity to perform representative inlet/outlet sampling and analysis campaigns at industrial scales regarding organic compounds and to propose options to overcome this issue. Centrifugation and drying processes only implied physical mechanisms as phase separation and water elimination. Hence, correct mass balance were expected observed for organic contaminants if sampling and analysis campaigns were representative. This was the case for hydrophobic and neutral compounds. For the other more hydrophilic and charged compounds, the mass balances were scarcely correct. Thus, the conventional sampling and analytical practices used with sludge should be questioned and adapted to better take into account the high heterogeneity of sludge and the evolution of matrix effect within sludge treatment processes on micropollutant determination. For the biological anaerobic digestion process where degradations can occur and removals can be observed, the mass balances were deeply interpreted for 60 contaminants. This process contributed to the elimination above 70% of 21 detected compounds including 16 pharmaceuticals, 2 phthalates, 2 hormones and 1 perfluorinated compound. Removals of domperidone, propranolol, escitalopram, lidocaine, verapamil and cefoperazone under this condition were reported for the first time.

What removals of pathogen indicators can be expected within large-scale wastewater treatment facilities in the context of wastewater reuse in Paris conurbation?

The fate of pathogen indicators (Escherichia coli - EC, intestinal enterococci - IE, RNA-F bacteriophages and spores of sulfite reducing bacteria - SSR) was extensively studied in Parisian large-scale wastewater treatment plants (WWTPs), based on conventional activated sludge, biofiltration or membrane bioreactor (MBR) processes. Between 14 and 87 campaigns were performed between 2014 and 2018 in five WWTPs. High removals of 3 log for both EC and IE, and lower removals of 1-2 log for SSR and RNA-F bacteriophages, were observed in conventional activated sludge and biofiltration WWTPs. The MBR WWTP achieves notably greater removals of 4.5-5.5 log for faecal bacteria and 3-4 log for SSR and RNA-F bacteriophages. This WWTP is the only one already in compliance with reuse standards, the other ones being non-compliant because of SSR and RNA-F bacteriophages. The implementation of a micro-grain activated carbon process would increase the WWTP removals of 0.8 log for faecal bacteria, due to particles retention, with no significant effect on both other pathogens. Ozonation (0.9-1.3 g O3/g dissolved organic carbon) or performic acid (0.8-1.2 ppm) would have greater benefits with additional removals of 1.5-2.5 log for EC, 1-2 log for IE and 0.5-1 log for SSR and RNA-F bacteriophages. Correlations between pathogen indicator removals and initial concentrations were found, as well as a significant decrease of RNA-F bacteriophage concentrations in Parisian raw wastewater, below 2 log. Thus, RNA-F bacteriophages could be a real issue to evaluate the compliance of Parisian wastewater with reuse. The time evolution of removals demonstrated that SSR is the most problematic parameter regarding reuse in conventional activated sludge and biofiltration WWTPs, as its initial concentration is high (5 log) but removals insufficient (<2 log). In contrast, removals of RNA-F bacteriophages greater than 2 log can be obtained within WWTPs completed or not with a tertiary treatment when the initial concentration in raw wastewater is sufficient. Correlations were also found between the removals of pathogen indicators and the removals of physico-chemical parameters, but they are not good enough to allow performance predictions.

Sludge conditioning, thickening and dewatering optimization in a screw centrifuge decanter: Which means for which result?

Centrifuge are common machines used for sludge thickening and dewatering in wastewater treatment plant but performances and optimal setting parameters are often difficult to predict and optimize, owing to complex mechanisms occurring during separation and high shear stresses undergone by flocs. Laboratory tests are necessary to assess performances and to screen chemicals and dosage in order to decrease optimization time at full scale. They include volatile matters characterization, drainage and CST tests vs mixing time, basket spin tests with shearing, limit dryness determination. The ability of these tests, to assess sludge dehydration and/or to select polymer and dosage, is discussed and is compared with performances obtained in a screw centrifuge decanter at lab and full scale.

Autonomous system for rapid field quantification of Escherichia coli in surface waters.

AIMS: The purpose of this work is to present and evaluate the performance of a novel Automatic Lab-in-vial Escherichia coli Remote Tracking technology based on an automated real-time defined substrate approach, implemented in both portable and in situ instruments. METHODS AND RESULTS: We present the fresh water calibration procedure, and assess performance using side-by-side comparison with most probable number (MPN) approaches in terms of accuracy, reproducibility and capability to correctly generate early-warning alerts. Long-term data from an operational in situ deployment at a potential bathing site is presented as well. CONCLUSIONS: Automatic Lab-in-vial Escherichia coli Remote Tracking technology is shown to be an accurate and rapid bacterial quantification technology, capable of autonomous in situ measurements with metrological capabilities comparable to those of an approved laboratory using MPN microplate techniques. SIGNIFICANCE AND IMPACT OF THE STUDY: Rapid quantification of bacterial pollution is a requirement in water quality applications ranging from recreational water use, agriculture and aquaculture to drinking and wastewater treatment. The method and instruments presented in this work should enable fast and accurate bacterial concentration measurements to be performed in a portable or in situ manner, thus simplifying operational logistics, reducing time-to-result delays, and eliminating sample transportation constraints associated with traditional techniques.

Non-target strategies by HRMS to evaluate fluidized micro-grain activated carbon as a tertiary treatment of wastewater.

Among the release solutions for reducing the discharge of organic and persistent contaminants in the aquatic environment, the use of a tertiary treatment in addition to existing conventional wastewater treatment processes is considered. The use of micro-grain activated carbon in a fluidized bed is a promising technique investigated in this study. The effluents from a large-scale pilot system were analyzed by liquid chromatography coupled with high-resolution mass spectrometry (QToF). Several strategies were deployed, namely molecular fingerprint comparison, suspected and non-target analyses, identification of refractory compounds to treatment, and finally, quantification of identified compounds. The evaluation of the molecular fingerprints provided evidence of the overall effect of the tertiary treatment on the treated wastewater quality. The suspected approach highlighted the presence of 83 pharmaceuticals and pesticides as well as transformation products in the effluents. The non-target approaches also highlighted compounds refractory to tertiary treatment, such as illicit drugs or some pharmaceuticals. The identification and quantification of identified compounds underscored the suitability of micro-grain activated carbon in eliminating many classes of pharmaceuticals with various physicochemical properties, such as anti-hypertensive, analgesic, anti-viral, antidepressant and even various pesticides.

Estimating ecosystem metabolism from continuous multi-sensor measurements in the Seine River.

Large rivers are important components of the global C cycle. While they are facing an overall degradation of their water quality, little remains known about the dynamics of their metabolism. In the present study, we used continuous multi-sensors measurements to assess the temporal variability of gross primary production (GPP) and ecosystem respiration (ER) rates of the anthropized Seine River over an annual cycle. Downstream from the Paris urban area, the Seine River is net heterotrophic at the annual scale (-226 gO2 m-2 year-1 or -264 gC m-2 year-1). Yet, it displays a net autotrophy at the daily and seasonal scales during phytoplankton blooms occurring from late winter to early summer. Multivariate analyses were performed to identify the drivers of river metabolism. Daily GPP is best predicted by chlorophyll a (Chla), water temperature (T), light, and rainfalls, and the coupling of daily GPP and Chla allows for the estimation of the productivity rates of the different phytoplankton communities. ER rates are mainly controlled by T and, to a lesser extent, by Chla. The increase of combined sewer overflows related to storm events during the second half of the year stimulates ER and the net heterotrophy of the river. River metabolism is, thus, controlled at different timescales by factors that are affected by human pressures. Continuous monitoring of river metabolism must, therefore, be pursued to deepen our understanding about the responses of ecosystem processes to changing human pressures and climate.

Nitrifying Kinetics and the Persistence of Nitrite in the Seine River, France.

Although a higher oxidation rate for nitrite than for ammonia generally prevents nitrite accumulation in oxic waters, nitrite concentrations in the Seine River (1-31 µM) exceed European norms. We investigated the kinetics of in situ ammonia- and nitrite-oxidizing communities in river water and wastewater treatment plant (WWTP) effluents to determine the role of pelagic nitrification in the origin and persistence of nitrite downstream of Paris. The main source of nitrite is the major Parisian WWTP, and its persistence, up to tens of kilometers downstream of the plant, is explained by low ammonia and nitrite oxidation rates and high river flow. Furthermore, similar nitrite and ammonia oxidation rates preclude a rapid consumption of both preexisting nitrite and nitrite produced by ammonia oxidation. Maximum ammonia oxidation rates are two to three times higher downstream than upstream of the WWTP, indicating the input of ammonia oxidizers and ammonia from the WWTP. In both river water and WWTP effluents, nitrite oxidizers were unable to oxidize all available nitrite. In the human-impacted Seine River, this phenomenon might be due to mixotrophy. This study highlights the low resilience of the river to nitrite contamination as well as the importance of managing nitrite, nitrifiers, and organic matter concentrations in WWTP effluents to avoid nitrite persistence in rivers.

Fate of emerging and priority micropollutants during the sewage sludge treatment: Case study of Paris conurbation. Part 1: Contamination of the different types of sewage sludge.

This article provides data on the contamination of different kinds of sludge (raw, centrifuged, digested, thermally dried sludge and sludge cake) from Paris conurbation by 71 various pollutants including pharmaceutical products (PHPs), hormones, perfluorinated acids (PFAs), linear alkylbenzene sulfonate (LAS), alkylphenols (APs), phthalates (PAEs), polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs). Very high contents of LAS (0.1-10g/kg dry matter - DM) compared to other compounds were found in all types of sludge followed by DEHP (10-100mg/kg DM) and fluoroquinolones (1-100mg/kg DM). APs were measured at intermediary contents in Parisian sludge, lying in the 2-20mg/kg DM range. Finally, hormones, PAHs, PCBs, PAEs, PFAs and the remaining PHPs were all found at contents lower than 1mg/kg DM. For most compounds (PHPs, PFOS, DEHP, PAHs), no significant differences in the micropollutant contents were found for similar types of sludge from different WWTP in Paris, highlighting the homogeneity of sludge contamination in downstream Paris catchment. The variability of concentration is rather high (coefficient of variation >100%) for several PHPs, PFAs or PCBs while it is moderate (<100%) or low (<50%) for fluoroquinolones, hormones, PAHs, APs or LAS. In addition, digestion seems to have a buffer effect as variabilities are lower in digested sludge for PHPs, PFAs, APs and PCBs. During sludge treatment (centrifugation, digestion, thermal drying, sludge conditioning+press filtration), the hormones, LAS, APs, PAHs, DEHP and PCBs concentrations increased, while those of PHPs and PFAs decreased. In the case of digestion, the increase of content can be explained by no pollutant removal or a lower removal than DM removal (concentration phenomenon) whereas the decrease underlines that the compound is more removed than the DM. In any case, these concentration variations presuppose the mechanisms of dissipation that could be attributed to volatilization, biotic or abiotic transformation (complete or with metabolites production), bound residues formation. In addition, data on sludge liquors - centrifuged (CW) and condensed (TDW) waters - from respectively centrifugation and thermal drying were collected. Several hormones, PHPs, PFAs, LAS, PAEs, APs, PCBs and PAHs were quantified in CW and TDW, displaying a transfer through the water removal. The concentrations observed are rather comparable to those found in wastewater.

Removal of a wide range of emerging pollutants from wastewater treatment plant discharges by micro-grain activated carbon in fluidized bed as tertiary treatment at large pilot scale.

Among the solutions to reduce micropollutant discharges into the aquatic environment, activated carbon adsorption is a promising technique and a large scale pilot has been tested at the Seine Centre (240,000 m(3)/d - Paris, France) wastewater treatment plant (WWTP). While most of available works studied fixed bed or contact reactors with a separated separation step, this study assesses a new type of tertiary treatment based on a fluidized bed containing a high mass of activated carbon, continuously renewed. For the first time in the literature, micro-grain activated carbon (µGAC) was studied. The aims were (1) to determine the performances of fluidized bed operating with µCAG on both emerging micropollutants and conventional wastewater quality parameters, and (2) to compare its efficiency and applicability to wastewater to former results obtained with PAC. Thus, conventional wastewater quality parameters (n=11), pharmaceuticals and hormones (PPHs; n=62) and other emerging pollutants (n=57) have been monitored in µGAC configuration during 13 campaigns. A significant correlation has been established between dissolved organic carbon (DOC), PPHs and UV absorbance at 254 nm (UV-254) removals. This confirms that UV-254 could be used as a tertiary treatment performance indicator to monitor the process. This parameter allowed identifying that the removals of UV-254 and DOC reach a plateau from a µGAC retention time (SRT) of 90-100 days. The µGAC configuration substantially improves the overall quality of the WWTP discharges by reducing biological (38-45%) and chemical oxygen demands (21-48%), DOC (13-44%) and UV-254 (22-48%). In addition, total suspended solids (TSS) are retained by the µGAC bed and a biological activity (nitratation) leads to a total elimination of NO2(-). For micropollutants, PPHs have a good affinity for µGAC and high (>60%) or very high (>80%) removals are observed for most of the quantified compounds (n=22/32), i.e. atenolol (92-97%), carbamazepine (80-94%), ciprofloxacin (75-95%), diclofenac (71-97%), oxazepam (74-91%) or sulfamethoxazole (56-83%). In addition, alkylphenols, artificial sweeteners, benzotriazole, bisphenol A, personal care products (triclocarban and parabens) and pesticides have removals lying in the 50 ->90% range. Overall, the fluidized bed of µGAC allows obtaining performances comparable to PAC at the same activated carbon dose. Indeed, the average removal of the 13 PPHs found at a high occurrence (>75%) in WWTP discharges is similar at 20 g/m(3) of µGAC (78-89%) and PAC (85-93%). In addition, this recycled µGAC operation leads to several operational advantages (no FeCl3, reactivable, higher SRT, higher treated flow) and has a stronger impact on the overall wastewater quality compared to PAC.

Influence of effluent organic matter on copper speciation and bioavailability in rivers under strong urban pressure.

This study focuses on spatiotemporal variations in the type of dissolved organic matter (DOM) and copper binding ability both upstream and downstream of Paris. It also compares the relative influence of both natural DOM upstream of Paris and effluent dissolved organic matter (EfDOM) output from a wastewater treatment plant (WWTP) on trace metal speciation and bioavailability in aquatic systems. In addition to the typical high- and low-affinity binding sites, a third family of very high-affinity binding sites has been highlighted for EfDOM. In receiving waters downstream of Paris during low-flow periods, the percentage of high- and very high-affinity sites originating from EfDOM reaches nearly 60 %. According to the speciation computation, the free copper concentration upstream of Paris exceeds the downstream Paris concentration by a factor of 2 to 4. As regards copper bioavailability, the highest EC50tot values were observed for EfDOM and downstream DOM, with a very low aromaticity and low UV absorbance. This finding suggests that specific ultraviolet absorbance (SUVA) is unlikely to be useful in assessing metal speciation and toxicity in aquatic systems subject to strong urban pressures. These results also highlight that the copper speciation computation for surface water exposed to considerable human pressures should include not only the humic and/or fulvic part of dissolved organic carbon but more hydrophilic fractions as well, originating for example from EfDOM.

Study of a large scale powdered activated carbon pilot: Removals of a wide range of emerging and priority micropollutants from wastewater treatment plant effluents.

The efficacy of a fluidized powdered activated carbon (PAC) pilot (CarboPlus(®)) was studied in both nominal (total nitrification + post denitrification) and degraded (partial nitrification + no denitrification) configuration of the Seine Centre WWTP (Colombes, France). In addition to conventional wastewater parameters 54 pharmaceuticals and hormones (PhPHs) and 59 other emerging pollutants were monitored in influents and effluents of the pilot. Thus, the impacts of the WWTP configuration, the process operation and the physico-chemical properties of the studied compounds were assessed in this article. Among the 26 PhPHs quantified in nominal WWTP configuration influents, 8 have high dissolved concentrations (>100 ng/L), 11 have an intermediary concentration (10-100 ng/L) and 7 are quantified below 10 ng/L. Sulfamethoxazole is predominant (about 30% of the sum of the PhPHs). Overall, 6 PhPHs are poorly to moderately removed (<60%), such as ibuprofen, paracetamol or estrone, while 9 are very well removed (>80%), i.e. beta blockers, carbamazepine or trimethoprim, and 11 are well eliminated (60-80%), i.e. diclofenac, naproxen or sulfamethoxazole. In degraded WWTP configuration, higher levels of organic matter and higher concentrations of most pollutants are observed. Consequently, most PhPHs are substantially less removed in percentages but the removed flux is higher. Thus, the PAC dose required to achieve a given removal percentage is higher in degraded WWTP configuration. For the other micropollutants (34 quantified), artificial sweeteners and phthalates are found at particularly high concentrations in degraded WWTP configuration influents, up to µg/L range. Only pesticides, bisphenol A and parabens are largely eliminated (50-95%), while perfluorinated acids, PAHs, triclosan and sweeteners are not or weakly removed (<50%). The remaining compounds exhibit a very variable fate from campaign to campaign. The fresh PAC dose was identified as the most influencing operation parameter and is strongly correlated to performances. Charge and hydrophobicity of compounds have been recognized as crucial for the micropollutant adsorption on PAC, as well as the molecular weight. Finally, a PAC dose of 10 mg/L allows an average removal of 72-80% of the sum of the PhPHs in nominal WWTP configuration. The comparaison of the results with those from the scarce other studies tends to indicate that an extrapolation of them to different PAC processes and to other WWTPs could be possible and relevant, taking into account the differences of water quality from WWTP to WWTP.

Ultrasound-guided synovial biopsy: a safe, well-tolerated and reliable technique for obtaining high-quality synovial tissue from both large and small joints in early arthritis patients.

OBJECTIVE: To determine the tolerability, safety and yield of synovial tissue in an early arthritis cohort using a minimally invasive, ultrasound (US)-guided, synovial biopsy technique in small, medium and large joints. METHODS: 93 sequential biopsy procedures were assessed from a total of 57 patients (baseline and 36 repeat biopsies at 6 months) recruited as part of the 'Pathobiology of Early Arthritis Cohort' study. Patients completed a tolerability questionnaire prior to and following the synovial biopsy procedure. The synovial biopsy was performed under US guidance with US images of the joint recorded prior to each procedure. Synovial tissue was harvested for immunohistochemistry and RNA extraction. RESULTS: Five different joint sites were biopsied (knee, elbow, wrist, metacarpal phalangeal and proximal interphalangeal). No significant complications were reported following the procedure. No difference in pain, swelling and stiffness of the biopsied joint from before and after the procedure was demonstrated. A median of 14 biopsy samples was retrieved from each procedure with 93% of biopsy procedures yielding good quality tissue. RNA yield was good in all joints and in repeat biopsies. Multivariant analysis demonstrated a significantly greater yield of RNA and graded tissue in relation to a high prebiopsy, grey-scale synovitis score (0-3, semiquantitative). CONCLUSIONS: A minimally invasive approach to synovial tissue harvesting, using US guidance, is both safe and well-tolerated by patients. Tissue quality/RNA yield is preserved in subsequent biopsies following therapeutic intervention. A high US grey-scale synovitis score is a predictor of good quality/quantity of tissue and RNA.

Phthalates and alkylphenols in industrial and domestic effluents: case of Paris conurbation (France).

Phthalates and alkylphenols are toxics classified as endocrine disrupting compounds (EDCs). They are of particular concern due to their ubiquity and generally higher levels found in the environment comparatively to other EDCs. Industrial and domestic discharges might affect the quality of receiving waters by discharging organic matter and contaminants through treated waters and combined sewer overflows. Historically, industrial discharges are often considered as the principal vector of pollution in urban areas. If this observation was true in the past for some contaminants, no current data are today available to compare the quality of industrial and domestic discharges as regards EDCs. In this context, a total of 45 domestic samples as well as 101 industrial samples were collected from different sites, including 14 residential and 33 industrial facilities. This study focuses more specifically on 4 phthalates and 2 alkylphenols, among the most commonly studied congeners. A particular attention was also given to routine wastewater quality parameters. For most substances, wastewaters from the different sites were heavily contaminated; they display concentrations up to 1200 µg/l for di-(2-ethylhexyl) phthalate and between 10 and 100 µg/l for diethyl phthalate and nonylphenol. Overall, for the majority of compounds, the industrial contribution to the flux of contaminant reaching the wastewater treatment plants ranges between 1 and 3%. The data generated during this work constitutes one of the first studies conducted in Europe on industrial fluxes for a variety of sectors of activity. The study of the wastewater contribution was used to better predict the industrial and domestic contributions at the scale of a huge conurbation heavily urbanized but with a weak industrial cover, illustrated by Paris. Our results indicate that specific investigations on domestic discharges are necessary in order to reduce the release of phthalates and alkylphenols in the sewer systems for such conurbations.

Priority and emerging pollutants in sewage sludge and fate during sludge treatment.

This paper aims at characterizing the quality of different treated sludges from Paris conurbation in terms of micropollutants and assessing their fate during different sludge treatment processes (STP). To achieve this, a large panel of priority and emerging pollutants (n=117) have been monitored in different STPs from Parisian wastewater treatment plants including anaerobic digestion, thermal drying, centrifugation and a sludge cake production unit. Considering the quality of treated sludges, comparable micropollutant patterns are found for the different sludges investigated (in mg/kg DM - dry matter). 35 compounds were detected in treated sludges. Some compounds (metals, organotins, alkylphenols, DEHP) are found in every kinds of sludge while pesticides or VOCs are never detected. Sludge cake is the most contaminated sludge, resulting from concentration phenomenon during different treatments. As regards treatments, both centrifugation and thermal drying have broadly no important impact on sludge contamination for metals and organic compounds, even if a slight removal seems to be possible with thermal drying for several compounds by abiotic transfers. Three different behaviors can be highlighted in anaerobic digestion: (i) no removal (metals), (ii) removal following dry matter (DM) elimination (organotins and NP) and iii) removal higher than DM (alkylphenols - except NP - BDE 209 and DEHP). Thus, this process allows a clear removal of biodegradable micropollutants which could be potentially significantly improved by increasing DM removal through operational parameters modifications (retention time, temperature, pre-treatment, etc.).

Biofiltration vs conventional activated sludge plants: what about priority and emerging pollutants removal?

This paper compares the removal performances of two complete wastewater treatment plants (WWTPs) for all priority substances listed in the Water Framework Directive and additional compounds of interest including flame retardants, surfactants, pesticides, and personal care products (PCPs) (n = 104). First, primary treatments such as physicochemical lamellar settling (PCLS) and primary settling (PS) are compared. Similarly, biofiltration (BF) and conventional activated sludge (CAS) are then examined. Finally, the removal efficiency per unit of nitrogen removed of both WWTPs for micropollutants is discussed, as nitrogenous pollution treatment results in a special design of processes and operational conditions. For primary treatments, hydrophobic pollutants (log K ow > 4) are well removed (>70 %) for both systems despite high variations of removal. PCLS allows an obvious gain of about 20 % regarding pollutant removals, as a result of better suspended solids elimination and possible coagulant impact on soluble compounds. For biological treatments, variations of removal are much weaker, and the majority of pollutants are comparably removed within both systems. Hydrophobic and volatile compounds are well (>60 %) or very well removed (>80 %) by sorption and volatilization. Some readily biodegradable molecules are better removed by CAS, indicating a better biodegradation. A better sorption of pollutants on activated sludge could be also expected considering the differences of characteristics between a biofilm and flocs. Finally, comparison of global processes efficiency using removals of micropollutants load normalized to nitrogen shows that PCLS + BF is as efficient as PS + CAS despite a higher compactness and a shorter hydraulic retention time (HRT). Only some groups of pollutants seem better removed by PS + CAS like alkylphenols, flame retardants, or di-2-ethylhexyl phthalate (DEHP), thanks to better biodegradation and sorption resulting from HRT and biomass characteristics. For both processes, and out of the 68 molecules found in raw water, only half of them are still detected in the water discharged, most of the time close to their detection limit. However, some of them are detected at higher concentrations (>1 µg/L and/or lower than environmental quality standards), which is problematic as they represent a threat for aquatic environment.

Direct amine-functionalisation of γ-Fe2O3 nanoparticles.

A novel and simple preparation of amine-modified γ-Fe2O3 nanoparticles is described. The presence of amine groups on the surface, instead of hydroxyl groups, will allow conjugation of biologically active molecules to the iron oxide nanoparticles without the need for a size increasing silica shell. Furthermore, the outer amine-layer increases the temperature of the γ-Fe2O3 to α-Fe2O3 structural transition in a similar way to previously reported cationic substitutions. This may suggest the formation of an oxide-nitride outer layer. Re-dispersion of the amine-modified γ-Fe2O3 nanoparticles led to the preparation of stable ferrofluids.

Removal of alkylphenols and polybromodiphenylethers by a biofiltration treatment plant during dry and wet-weather periods.

This paper investigates the occurrence of alkylphenols (APs) and polybromodiphenylethers (PBDEs) in raw wastewater during dry and wet-weather periods, and their removal by physico-chemical lamellar settling and biofiltration techniques. Due to in-sewer deposit erosion and, to a lesser extent, to external inputs, raw effluents exhibit from 1.5 to 5 times higher AP and PBDE concentrations during wet periods compared with dry ones. The lamellar settler obtains high removal of APs and PBDEs under both dry and wet-weather flows (>53% for Σ(6)AP and >89% for Σ(4)PBDE), confirming the insensitivity of this technique to varying influent conditions. Indeed, despite the higher pollutant concentrations observed in raw effluents under wet-weather flows, adjusting the addition of coagulant-flocculent allows for efficient removal. By combining physical and biological processes, the biofiltration unit treats nutrient pollution, as well as Σ(6)AP and Σ(4)PBDE contamination (58 ± 5% and 75 ± 6% respectively). Although the operating conditions of the biofiltration unit are modified during wet periods, the performance in nutrient pollution, APs and light PBDE congeners remains high. Nevertheless, lower efficiency has been noted in nitrogen pollution, i.e. no denitrification occurs, and BDE-209 (not removed during wet-weather periods). In conclusion, this study demonstrates that the combination of both techniques treats AP and PBDE pollution efficiently during dry periods, but that they are also suitable for stormwater treatment.

Priority substances in combined sewer overflows: case study of the Paris sewer network.

This study was undertaken to supply data on both priority pollutant (PP) occurrence and concentrations in combined sewer overflows (CSOs). A single rain event was studied on 13 sites within the Paris sewer network. For each sample, a total of 66 substances, including metals, polycyclic aromatic hydrocarbons (PAHs), pesticides, organotins, volatile organic compounds, chlorobenzenes, phthalates and alkylphenols were analyzed. Of the 66 compounds analyzed in all, 40 PPs including 12 priority hazardous substances were detected in CSOs. As expected, most metals were present in all samples, reflecting their ubiquitous nature. Chlorobenzenes and most pesticides were never quantified above the limit of quantification, while the majority of the other organic pollutants, except DEHP (median concentration: 22 µg.l(-1)), were found to lie in the µg.l(-1) range. For the particular rain event studied, the pollutant loads discharged by CSOs were evaluated and then compared to pollutant loads conveyed by the Seine River. Under the hydraulic conditions considered and according to the estimations performed, this comparison suggests that CSOs are potentially significant local source of metals, PAHs and DEHP. Depending on the substance, the ratio between the CSO and Seine River loads varied from 0.5 to 26, underscoring the important local impact of CSOs at the scale of this storm for most pollutants.