[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | In recent years, unsaturated/saturated vertical flow constructed wetlands(VFCW) treating raw wastewateraregradually considered as apromising solution for their adaptation under various climatic conditions. These facilities provide surface optimization but alsobetter treatment efficiencies compare to classical French VFCW.The main performance improvements are: SS entrapment and carbon consumption for denitrification within saturated layer.When total nitrogen, by nitrification and denitrification,istargeted in the two successive zones, a design compromise has to be fund between nitrification efficiency and available carbon source for denitrification. As performance largely depends on unsaturated and saturated layers depths,a better understanding of their quantitative effects on treatment performance is essential for the adaptation of this system under various installation conditions. The aim of this study was to estimate the influence of these two linked design parameters onN efficiency with a focus onremoval limitations in regard to nitrogen loads. For this purpose, two different pilot-scale experimental configurations were designed: (i) 45 cm of unsaturated and 25 cm of saturated layers and (ii) 55 cm of unsaturated and 35 cm of saturated layers. The mature pilots were operated over 5 months using real wastewater with a feeding/resting period cycle of 3.5/3.5 days with a daily hydraulic load of 0.36 m d-1.In order to vary inlet nitrogen loads, ammonium nitrogen enrichments were added to vary loads from 10 to 40 g N m-2 d-1.24h flow composite samples at inlet and outlet of each pilot were semiweekly collected and analyzed for the following parameters: total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), Kjeldahl nitrogen (TKN), ammonium, nitrate, phosphate and sulfate. Online measurement on a minute time step were done for inlet/outlet flows, oxygen content at three different depths, outlet ammonium and nitrate concentrationsby ion specific probes, and temperature. The paper will present the performance and limitations ofthe two configurations.Dynamics of nitrogen removal processes will be discussed in relation to physicochemical conditions (temperature, oxygen content, hydraulic retention time, carbon sources, etc.).

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | The classic design of French constructed wetlands (CW) consists in two successive stages of vertical flow filters (VFFs). While this configuration permits full nitrification, it also needs a large surface area (> 2 m²/pe). Therefore high ammonium removal efficiencies are of interest for compact systems such as single stage CW.The use of zeolite as filtrating medium could fix the problem thanks to itsexchange capacity and its high affinity for ammonium. Indeed, the ammonium is adsorbed during the feeding cycle then nitrified during the rest period.This study aims to assess the feasibility of ammonium removal by zeolite in a first stage VFF fed with raw sewage. Seven columns (40 cm-depth, 107 cm²) filled with zeolite under a gravel layer and one control without zeolitewere studied over four months. All columns, except a zeolite-control, were packed with inoculated media froma treatment plant. The columns have been operated in a sequential mode of feeding and rest periods of 3.5d and 7d, respectively, with synthetic solution of ammonium (100mgNH4-N/L). Two columns were fed with different concentrations of ammonium while two others were also fed sodium in order to assess the impact of the ammonium concentration and the presence of competitive species, respectively. The nitrogen concentrations (ammonium, nitrite and nitrate) were measured at the inlet and the outlet.

International audience | For herbivore insects, digesting can be somewhat challenging, as the defense mechanisms evolved by plants, including the release of phenolics like the non-protein amino acid l-3,4-dihydroxyphenylalanine (l-DOPA), can cause fitness costs. In addition, industrial and agricultural activities have elevated the amounts of iron that can be found in nature and more particularly FeSO4 that is used as fertilizer. Traces of iron can enhance the auto-oxidation of l-DOPA, in turn, generating reactive oxygen species (ROS) and consequently oxidative stress in insects. We examined the effects of the ion Fe2+ (as FeSO4) and l-DOPA on fifth instars of the desert locust Schistocerca gregaria. We measured the level of oxidative damage occurring to macromolecules (proteins and lipids) from midgut and thoracic tissues and assessed the activities of responsive antioxidant enzymes. Injected l-DOPA and redox-active metal iron generated ROS which caused oxidative damages to proteins and lipids to S. gregaria. The protein carbonyls and lipid peroxides present in tissue homogenates were elevated in treated insects. No synergism was observed when l-DOPA was co-injected with Fe2+. K (m) values of superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) were 4.3, 2.6, and 4.0 mM in thoracic muscles and 5.00, 2.43, and 1.66 mM in whole midgut for SOD, GR, and GPx, respectively, and 8.3 and 3.43 M for catalase (CAT) in the two tissues, respectively. These results suggest higher affinities of GPx and CAT to H2O2 in midgut than in muscles. The time-course changes in activities of antioxidant enzymes and amounts of protein carbonyls and lipid peroxides showed fluctuating patterns, suggesting complex interactions among macromolecules, l-DOPA and FeSO4, and their degradation products. Our results demonstrated the stressful effects of l-DOPA and FeSO4, proving that iron-containing fertilizers are pollutants that can strongly affect S. gregaria.

International audience | Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive-also called hormetic-effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure

International audience | Insecticides have long been used as the main method in limiting agricultural pests, but their widespread use has resulted in environmental pollution, development of resistances, and biodiversity reduction. The effects of insecticides at low residual doses on both the targeted crop pest species and beneficial insects have become a major concern. In particular, these low doses can induce unexpected positive (hormetic) effects on pest insects, such as surges in population growth exceeding what would have been observed without pesticide application. Methomyl and chlorpyrifos are two insecticides commonly used to control the population levels of the cotton leafworm Spodoptera littoralis, a major pest moth. The aim of the present study was to examine the effects of sublethal doses of these two pesticides, known to present a residual activity and persistence in the environment, on the moth physiology. Using a metabolomic approach, we showed that sublethal doses of methomyl and chlorpyrifos have a systemic effect on the treated insects. We also demonstrated a behavioral disruption of S. littoralis larvae exposed to sublethal doses of methomyl, whereas no effects were observed for the same doses of chlorpyrifos. Interestingly, we highlighted that sublethal doses of both pesticides did not induce a change in acetylcholinesterase activity in head of exposed larvae

International audience | Barrage fishponds may represent a significant surface water area in some French regions. Knowledge on their effect on water resources is therefore necessary for the development of appropriate water quality management plans at the regional scale. Although there is much information on the nutrient removal capacity of these water bodies, little attention has been paid to other agricultural contaminants such as pesticides. The present paper reports the results of a 1-year field monitoring of pesticide concentrations and water flows measured upstream and downstream from a fishpond in North East France to evaluate its capacity in reducing pesticide loads. Among the 42 active substances that had been applied on the fishpond's catchment, seven pesticides (five herbicides, two fungicides) were studied. The highest concentration in the inflow to the pond was 26.5 mu g/L (MCPA), while the highest concentration in pond outflow was 0.54 mu g/L (prosulfocarb). Removal rates of dissolved pesticides in the fishpond ranged from 0-8 % (prosulfocarb) to 100 % (clopyralid). Although not primarily designed for the treatment of diffuse sources of pesticides, the studied fishpond had the potential to do so.

International audience | Antibiotic use in the early 1900 vastly improved human health but at the same time started an arms race of antibiotic resistance. The widespread use of antibiotics has resulted in ubiquitous trace concentrations of many antibiotics in most environments. Little is known about the impact of these antibiotics on microbial processes or “non-target” organisms. This mini-review summarizes our knowledge of the effect of synthetically produced antibiotics on microorganisms involved in biogeochemical cycling. We found only 31 articles that dealt with the effects of antibiotics on such processes in soil, sediment, or freshwater. We compare the processes, antibiotics, concentration range, source, environment, and experimental approach of these studies. Examining the effects of antibiotics on biogeochemical processes should involve environmentally relevant concentrations (instead of therapeutic), chronic exposure (versus acute), and monitoring of the administered antibiotics. Furthermore, the lack of standardized tests hinders generalizations regarding the effects of antibiotics on biogeochemical processes. We investigated the effects of antibiotics on biogeochemical N cycling, specifically nitrification, denitrification, and anammox. We found that environmentally relevant concentrations of fluoroquinolones and sulfonamides could partially inhibit denitrification. So far, the only documented effects of antibiotic inhibitions were at therapeutic doses on anammox activities. The most studied and inhibited was nitrification (25–100 %) mainly at therapeutic doses and rarely environmentally relevant. We recommend that firm conclusions regarding inhibition of antibiotics at environmentally relevant concentrations remain difficult due to the lack of studies testing low concentrations at chronic exposure. There is thus a need to test the effects of these environmental concentrations on biogeochemical processes to further establish the possible effects on ecosystem functioning

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | CWs for combined sewer overflow treatment (CSO CWs) are vertical flow filters with detention basin and fixedoutflow rate. They receive stochastic loadsinduced by urban runoff and protect natural waters against pollutants and streambed erosion.However, due to the stochastic nature of flows, concentrations and periodicity, optimizing CSO CW design requires a dynamic approach.Computational tools are available but process-based models are difficult to handle [1].Moreover, the absence of user interface in design-oriented tools (e.g. RSF_Sim [2]) demands manual data handling and simulations of multiple designs. Therefore, a new tool called Orage was developed. Orage relies on a core model similar to RSF_Sim.Long-term hydraulics, COD and NH4-N were simulated with good accuracy. Filter material selection and scaling is based on inflow data series and a low number of inputs. The iterative shell calls for simulations repeatedly to (1) optimize hydraulics; (2) select the simplest material which isnecessary to satisfy emission requirements on NH4-N and (3) determine the minimalfilter area at which legislative thresholds can be met. A design is optimized if the maximum of moving average on simulated effluent concentrations (Peak_MA_cc) is at the legislative threshold (NH4N) or below (COD). Fig. 1 shows an example of the iteration process.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | According to French standards, constructed wetlands treating combined sewer overflow (CSO CWs) are vertical flow filters with detention basin and outflow limitation. Their purpose is to treat rapid loads of wastewater with stochastic volumes, concentrations and periodicity. The first full-scale CSO CW at Marcy l‘Etoile was monitored to provide in-depth understanding of hydraulics and nitrogen dynamics. Monitoring lasted for three years incl. online equipment. The water content in the media was visualized along the longitudinal section of the filter to follow hydraulics in the fill stage. Tracer tests showed shortcutting at this stage weakening as the filter saturated which tallied with peaks of NH4-N concentrations diminishing at the outflow side. Adverse shortcutting effects can be diminished by minimizing fill time of the media. As for nitrogen dynamics, adsorption capacities showed no difference in the two filter sides, one with a sand-zeolite mixture and the other with pozzolana. An equation was fitted to temperature and adsorbed NH4-N mass measurements to calculate inter-event nitrification. The rate was found to double with every 5.7 °C. The results helped to calibrate the design-support software Orage. Finally, the washout dynamics of NO3-N were analysed to consider the possibility of a second filter stage for denitrification.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | The scope of this study is to research the removal of NH4 +-N from domestic wastewater using different porous and reactive materials by 1) increasing biological activity and 2) adsorption process. Experimental setup consisted of pilot scale VFCW (2.3 m2), which were put in operation in August 2014 receiving real raw domestic wastewater near a vertical flow wastewater treatment plant in the central region of France (L‘Encloitre, 37360). Two types of filtration media were tested 1) Leca® (L30M) and 2) natural zeolite (Z10M). Pilots were fed under regular feeding/resting periods (3´/7 days) and the nominal loading rate was of 300 g COD m-2 d-1 and 33 g.N.m2.d-1 in the operating filter. Results show a good treatment efficiency of domestic wastewater by the two French-Vertical Flow constructed Wetland (VFCWs) with more than 94% and 85% removal rate for TSS and COD for both filters respectively. Results also showed an increase of the NH4 +-N with the use of natural zeolite. The overall removal of more than 80% observed for Z10M seems to be linked to the effect of the ion exchange and adsorption properties of zeolite.