[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | An ion exchange process was assessed to improve ammonium removal by vertical flow filters. Six columns, filled with gravel and zeolite (30cm and 10cm, respectively), were compared with a standard column with 40 cm of gravel. Columns were fed for 3.5 days with semi-synthetic wastewater then rested for 7 days. Each column, filled with zeolite, had different inlet characteristics in order to study the effects of operational parameters pointed out as affecting the ion exchange process. Two columns assessed the impact of concentration (100mgNH4-N.L-1 versus 2000mgNH4-N.L-1) on exchange capacity and performance. The effect of competition with another cation on efficiency and saturation rate was studied at three different concentrations of sodium (0 mg.L-1, 85 mg.L-1 and 300 mg.L-1, respectively). Finally, regeneration of exchange capacity by nitrification as well as its effects on treatment efficiency was studied. Although zeolite showed promising results in the early stages of operation (>80%), performances quickly declined, until reaching similar efficiency as the standard (60%), suggesting insufficient regeneration. Moreover the concentration strongly affected the exchange capacity, the latter one being quite low for the range of ammonium concentrations usually observed in domestic wastewater. The sodium supply did not result in performance reductions for the studied conditions.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | CWs for combined sewer overflow treatment (CSO CWs) are vertical flow filters with detention basin and fixed outflow rate. They receive stochastic loadsinduced by urban runoff and protect natural waters against pollutants and streambed erosion. Thefull-scale site at Marcy l‘Etoile was monitored to gain data about hydrology and to quantify NH4-N adsorption capacities and nitrification rate. The throttled outlet ensuresa uniformflow in the porous media, butonly aftersaturation. Until then,the percolation is focused to the inletzone. As only a partof the filteris water-contacted and detention times are shorter than normal, removal performances are lower. The phenomenon is referred to as shortcutting, a temporary state at commencing load, which might last at low inflow rates. Eighteen TDR probes weredug in the longitudinal section of the filter to follow changes in the water content. This enabled to createan animation of the expansion of saturated area until complete saturation. Furthermore, tracer tests were carried out to signify shortcutting at different stages in the filter (Fig. 1).The filter was fed at the inlet point at a fixed and lowrate until saturation and three fluorescein pulses were dosed withidenticaldelay.The basin was flooded after to follow tracer passage and washout. Results were used to parameterizethemodel-based design-support tool Orage [1]and to suggest an improvementof the outflow limitationstructureto minimize shortcutting.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | Plants are essential in Constructed Wetland (CW) functioning. When implementing systems in tropical area, Phragmites autralis cannot be always selected because of its invasive characteristics. In Vertical Flow Constructed Wetland (VFCW) fed with raw wastewater, the main role of plant is their mechanical action that avoids clogging of the deposit organic matter. If alternative species have already been used in some tropical climate studies, it is generally not for such systems and without trying to do a real screening of numerous alternatives species. This paper presents a methodology to select species among a hundred studied, as well as promising plants that have been tested in batch and in full scale. Species from Zingiberales order showed strong adaptation to the main stresses generated by VFCW. They have long vegetative cycle that may require weed growth control after plantation but low harvesting frequency. Root system with long rhizomes like Heliconia psittacorum should have priority to ensure homogeneous growth and avoid clumps. To limit phytosanitary risk with Musaceæ (Banana tree) Canna indica or Canna glauca must be preferred. Species from the Cyperus genus demonstrate good adaptation too and might be interesting, especially when a high stems density is required (planted sludge drying bed).

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.

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED | International audience | The German guidelinefor the dimensioning, construction, and operation of constructed wetlands for biological treatment of domestic and municipal wastewater, which last published in March 2006, has recently been revised. The guideline applies to small wastewater treatment systems of less than 50 Person Equivalents (PE), municipal treatment plants up to 1.000 – 3.000 PE (with combined or separated sewers), treatment systems which use constructed wetlands as a polishing step, and small wastewater treatment systems which are operated seasonally (summer months only).The revision is based on a wide range of experience gained in recent years in the use of treatment wetlands in Germany and in Europe. Previous to the revisions, the proposed changes were discussed in a public hearing in Potsdam, Germany in January 2014. The final revisions were released for public review in October 2015. The finalized document is anticipated to be put into effect in April, 2016. A number of constructed wetland designs appear for the first time in the new guideline. Two-stage unsaturated vertical flow gravel filters which receive raw wastewater in the first stage (based on experience in France) as well as two-stage unsaturated vertical flow filters receiving primarytreated wastewater (based on experience in Austria) are now included. The revisions also include new dimensioning for unsaturated vertical flow filters with lava sand as the main treatment media, as well as aerated treatment wetlands, both as secondary treatment steps. Recommendations are also provided for seasonally operated constructed wetlands, as well as constructed wetlands for graywater treatment. With the publication of the new guideline, horizontal subsurface flow constructed wetlands are no longer supported as a secondary treatment stage in Germany, and are recommended only as a tertiary or polishing stage. Existing horizontal subsurface flow wetlands are allowed to continue operation, provided the systems are not hydraulically or organically overloaded, and that they continue to receive routine operations and maintenance. This presentation will outline the key points of the newly revised DWA-A 262 German constructed wetland guideline.

Pollution of the oceans by microplastics (<5 mm) represents a major environmental problem. To date, a limited number of studies have investigated the level of contamination of marine organisms collected in situ. For extraction and characterization of microplastics in biological samples, the crucial step is the identification of solvent(s) or chemical(s) that efficiently dissolve organic matter without degrading plastic polymers for their identification in a time and cost effective way. Most published papers, as well as OSPAR recommendations for the development of a common monitoring protocol for plastic particles in fish and shellfish at the European level, use protocols containing nitric acid to digest the biological tissues, despite reports of polyamide degradation with this chemical. In the present study, six existing approaches were tested and their effects were compared on up to 15 different plastic polymers, as well as their efficiency in digesting biological matrices. Plastic integrity was evaluated through microscopic inspection, weighing, pyrolysis coupled with gas chromatography and mass spectrometry, and Raman spectrometry before and after digestion. Tissues from mussels, crabs and fish were digested before being filtered on glass fibre filters. Digestion efficiency was evaluated through microscopical inspection of the filters and determination of the relative removal of organic matter content after digestion. Five out of the six tested protocols led to significant degradation of plastic particles and/or insufficient tissue digestion. The protocol using a KOH 10% solution and incubation at 60 °C during a 24 h period led to an efficient digestion of biological tissues with no significant degradation on all tested polymers, except for cellulose acetate. This protocol appeared to be the best compromise for extraction and later identification of microplastics in biological samples and should be implemented in further monitoring studies to ensure relevance and comparison of environmental and seafood product quality studies.

Plastic ingestion by marine biota has been reported for a variety of different taxa. In this study, we investigated 290 gastrointestinal tracts of demersal (cod, dab and flounder) and pelagic fish species (herring and mackerel) from the North and Baltic Sea for the occurrence of plastic ingestion. In 5.5% of all investigated fishes, plastic particles were detected, with 74% of all particles being in the microplastic (< 5 mm) size range. The polymer types of all found particles were analysed by means of Fourier transform infrared (FT-IR) spectroscopy. Almost 40% of the particles consisted of polyethylene (PE). In 3.4% of the demersal and 10.7% of the pelagic individuals, plastic ingestion was recorded, showing a significantly higher ingestion frequency in the pelagic feeders. The condition factor K was calculated to test differences in the fitness status between individuals with and without ingested plastic, but no direct effect was detected