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International audience; The reuse of wastewater aims to mobilize and treat, for certain uses and under certain conditions, water that has already been used. Rather than discharging wastewater into the natural environment, this practice aims to recover it by replacing the mobilization of water withdrawn from the environment [van Loosdrecht and Brdjanovic, 2014]. By moving from a linear logic of the mobilization and use of water to a circular approach, the objective pursued is to reduce the pressure, qualitative then quantitative, on the resources while limiting, as far as possible, the usage conflicts. It is in fact a question of passing from a simple competitive mode which strongly mobilizes resources, to a complex mode, known as “circular”, of putting in complementarity of uses. This approach initially mainly concerned agricultural uses insofar as agricultural needs represent the majority of the water mobilized, including developed countries [UN Water 2018]. Cities integrate specific issues that are characterized by significantly different options from those that can be found in rural areas. In the city, the recovery of wastewater has both material aspects (water, nutrients, critical metals, biopolymers, etc.) and energy aspects (recovery of heat from the networks, production of energy by biological means and /or thermal,…) which should be integrated on an appropriate scale according to the problems addressed (housing, building, district, city, territory or hydrological basin). To study the conditions under which REUSE can develop and be implemented in a safe and sustainable manner, research is needed [Ait-Mouheb et al., 2018]. If it represents an opportunity in certain territories where wastewater can be mobilized, it is also necessary to underline the limits of this practice in territories where the wastewater discharged into the environment is necessary to maintain the low water levels of rivers and rivers, or where soils may be affected, for example, by the salinity of these waters. In addition, studies of the social, economic and environmental dimensions differ significantly depending on the uses envisaged and the situations considered. To meet these challenges, the REUSE network of INRAE (cf. www6.inrae.fr) proposes to adopt a multidisciplinary and multi-scale approach by mobilizing not only the disciplines that can be considered as falling within the field of technologies and environmental engineering but also all of those relating to the human and social sciences, economics, legal, and participatory sciences.

International audience; Drip irrigation is one of the most efficient irrigation techniques, but it is susceptible to dripper clogging. This study proposes a novel and non-destructive method based on visible and near infrared (Vis/NIR) spectroscopy coupled with chemometric methods for the discrimination and thickness estimation of physical and chemical fouling in drip-irrigation systems. Four representative materials linked to physical and chemical clogging (kaolin, bentonite, sand and calcium carbonate) at different thicknesses were selected to illustrate the potential of the approach. Partial least squares regression (PLSR) and its modification partial least squares with discriminant analysis (PLS-DA) were selected for the modelling of clogging materials. The PLS-DA model was able to predict with 96.97% accuracy all classes of materials. The PLSR models were able to estimate fouling thickness with relative prediction errors comprised between 134 μm and 164 μm. This difference appears mainly to be due to the physical properties of the selected materials. This prediction accuracy enabled the estimation of the clogging thickness between 10 and 21% of dripper channel coverage depending on the dripper channel section and the material under study. The proposed method offers an appropriate approach for clogging studies in drip irrigation systems that could be transferred to field applications.

International audience; Unlike many structuring projects, treated wastewater reuse projects are rarely subjected to economic analysis. And when they are, the social and environmental benefits and costs are often not accounted for or are not properly quantified. Here we show that the widely used cost-benefit analysis method showing the profitability of a project from the whole of the community's point of view can be adapted to treated wastewater reuse projects. The remaining evaluation difficulties are more due to the system's complexity rather than its methodological limits. Indeed, the operator must be able to understand, formalize and imagine constraints and risks associated with different domains such as urbanism, agriculture, climate, hydrology and trade. Remaining uncertainties over key parameter values can, however, be properly considered through scenarios and/or stochastic approaches. We illustrate the implementation of this methodological approach with two case studies: Clermont-Ferrand where treated wastewater is reused by a collective irrigation network; and Cannes where surface and groundwater recharge can enable indirect reuse for multiple purposes including indirect potable water production. These two French case studies highlight how economic analysis, dealing with uncertainties, can support decision making.; Les projets de réutilisation des eaux usées traitées font rarement l’objet d’analyses économiques. Lorsque c’est le cas, les coûts et bénéfices sociaux et environnementaux ne sont pas correctement pris en compte ou quantifiés. Nous montrons ici que la méthodologie d’analyse coût–bénéfices (ACB) permettant d’évaluer la rentabilité d’un projet à l’échelle d’un territoire peut être adaptée à l’évaluation de projets de réutilisation des eaux usées traitées. La méthodologie employée est bien maitrisée et les difficultés de mise en oeuvre sont davantage liées à la complexité du système. L’opérateur doit en effet être en mesure de comprendre, de formaliser et d’imaginer les contraintes et les risques associés à différents domaines tels que l’urbanisme, l’agriculture et l’hydrologie. Les incertitudes résiduelles sur les valeurs de paramètres clés peuvent être prises en compte par l’étude de différents scénarios et/ou par des approches stochastiques. Nous illustrons cette approche à travers les études de cas français de Clermont-Ferrand où des eaux usées traitées sont réutilisées par un réseau collectif d’irrigation, et de Cannes où la recharge de milieux permet la réutilisation indirecte pour différents usages, dont la production indirecte d’eau potable. Ces études de cas illustrent comment l’analyse économique peut aider à la prise de décision.

International audience; Rotary water jets are commonly used in the world of agriculture, particularly in irrigation and in treatment with pesticides in the form of micro-sprinklers. However, their study is not very well developed, even though the problems linked to water resource losses or the drift of pesticides in the atmosphere are well known. Controlling the size distribution of the drops that are generated becomes essential to avoid these problems. The observation of the fragmentation of a rotating jet is implemented in this study. The shadowgraphy method coupled with a drop size and velocity detection algorithm has been adapted for this rotating system. Different modes of rupture can be observed and drop size distributions are analyzed. Primary atomization is controlled by the orthoradial air velocity generated by the rotation and by the stretching of the ligaments due to the Coriolis and centrifugal forces. We compare the different modes of fragmentation as a function of the aerodynamic forces created by the rotation and the momentum flux of the water jet in the air.

Drip irrigation is an efficient and safe system for reusing wastewater in agriculture. Since emitter clogging is its main limitation, filtration is needed for preventing it. Media filters are commonly used when irrigation water has a high particle load. However, particle removal through a media bed in media filters used in drip irrigation systems has not been widely studied mainly due to experimental difficulties. To overcome this issue a new methodology using optical coherence tomography (OCT) is presented here. Experiments were carried out on a media filter at laboratory scale using wastewater. Once the filter was clogged, several 20 mm slices were taken and the retained total suspended solids were analysed by gravimetry. Following this, particles retained at six different locations of each slice were also determined using OCT. Results show a good agreement between total suspended solids experimentally determined and particles determined with OCT, especially when pixels attributed to particles were 30–45% of the total. Therefore, OCT could be a useful technique for assessing particle retention at different media depths The authors would like to express their gratitude to Spanish Research Agency and the European Regional Development Fund for their financial support through Grant RTI2018-094798-B-100. They also want to thank the University of Girona for funding the research stages of Miquel Duran-Ros and Carles Solé-Torres at INRAE Montpellier (France). The authors also gratefully acknowledge the financial support of the French Water Agency Rhône Méditerranée Corse, project “Experimental platform for the reuse of reclaimed wastewater in irrigation, Murviel-lès-Montpellier” Open Access funding provided thanks to the CRUE-CSIC agreement with Elsevier

International audience; The Food-Energy-Water (FEW) nexus for urban sustainability needs to be analyzed via an integrative rather than a sectoral or silo approach, reflecting the ongoing transition from separate infrastructure systems to an integrated social-ecological-infrastructure system. As technology hubs can provide food, energy, water resources via decentralized and/or centralized facilities, there is an acute need to optimize FEW infrastructures by considering cost-benefit-risk tradeoffs with respect to multiple sustainability indicators. This paper identifies, categorizes, and analyzes global trends with respect to contemporary FEW technology metrics that highlights the possible optimal integration of a broad spectrum of technology hubs for possible cost-benefit-risk tradeoffs. The challenges related to multiscale and multiagent modeling processes for the simulation of urban FEW systems were discussed with respect to the aspects of scaling-up, optimization process, and risk assessment. Our review reveals that this field is growing at a rapid pace and the previous selection of analytical methodologies, nexus criteria, and sustainability indicators largely depended on individual FEW nexus conditions disparately, and full-scale cost-benefit-risk tradeoffs were very rare. Therefore, the potential full-scale technology integration in three ongoing cases of urban FEW systems in Miami (the United States), Marseille (France), and Amsterdam (the Netherlands) were demonstrated in due purpose finally.

As drip irrigation develops rapidly worldwide, the need for a standardized method to evaluate emitters’ clogging sensitivity is reinforced. Methodologies for evaluating the sensitivity of e...

A possible way to save agricultural water is to improve global irrigation efficiency, defined as the ratio between the irrigation water volume used for crop transpiration and the total irrigation water volume. Higher irrigation efficiency leads to higher irrigation productivity ("more crop per drop") and profitability in relation to irrigation water costs: higher financial expectations for the same water and energy costs or identical financial expectations for lesser water and energy costs.Improvements of irrigation efficiency may be sought either from better performing material (contextual relevance, technical quality or durability) or from optimized irrigation strategies with multiple levers of action (dates, doses, scheduling or trigger criteria, leaning on weather forecasts or not) and expected constraints (availability, quota, prefecture decrees).It is even possible to handle these two issues at once by(i) evaluating the irrigation water losses attributable to material (e.g. accidental pipe rupture or unavoidable intrinsic losses when using rainguns, spatial heterogeneity of water delivery),(ii) evaluating the losses due to inadequate irrigation strategies (drainage or evaporation of irrigation water, excessive irrigation water storage in soils, losses due to wind drift)(iii) gathering all losses in a "cascade scheme" that organizes them in phenomenological and chronological manner, somehow assuming successive losses "from the canal to plant roots",(iv) exploring numerous irrigation scenarios that would allow reducing losses, improving efficiency and finally finding the minimal irrigation water amount required to reach the target agricultural yield (or fulfil a typical set of contradictory constraints, e.g. irrigation quota vs. objectives in crop yield profitability and possibly no drainage) This was the scope of the recent development of the "Efficiency" module of the Optirrig model built for the generation, analysis and optimisation of crop irrigation scenarios.

Mediterranean‐African countries (MACs) face a major water crisis. The annual renewable water resources are close to the 500 m3/capita threshold of absolute water scarcity, and water withdrawals exceed total renewable water resources by 30%. Such a low water availability curbs economic development in agriculture, which accounts for 86% of freshwater consumption. The analysis of the current situation of wastewater treatment, irrigation, and water management in MACs and of the research projects targeted to these countries indicates the need for 1) an enhanced capacity to analyze water stress, 2) the development of water management strategies capable of including wastewater reuse, and 3) development of locally adapted water treatment and irrigation technologies. This analysis shaped the MADFORWATER project (www.madforwater.eu), whose goal is to develop a set of integrated technological and management solutions to enhance wastewater treatment, wastewater reuse for irrigation, and water efficiency in agriculture in Egypt, Morocco, and Tunisia. MADFORWATER develops and adapts technologies for the production of irrigation‐quality water from drainage canals and municipal, agro‐industrial, and industrial wastewaters and technologies for water efficiency and reuse in agriculture, initially validated at laboratory scale, to 3 hydrological basins in the selected MACs. Selected technologies will be further adapted and validated in 4 demonstration plants of integrated wastewater treatment and reuse. Integrated strategies for wastewater treatment and reuse targeted to the selected basins are developed, and guidelines for the development of integrated water management strategies in other basins of the 3 target MACs will be produced. The social and technical suitability of the developed technologies and nontechnological tools in relation to the local context is evaluated with the participation of MAC stakeholders and partners. Guidelines on economic instruments and policies for the effective implementation of the proposed water management solutions in the target MACs will be developed.

Clay particles under certain physico-chemical and hydrodynamic conditions can form agglomerates after passing through a filtering system, which favours clogging of the emitters. The main factors interfering with the aggregation potential of clay particles are the type of clay mineral, pH, and ionic strength of the irrigation water. This study analysed the influence of ionic strength and type of clay mineral on clogging, discharge variation, and particle deposition in turbulent-flow non-pressure compensating drippers. Two types of clay (kaolinite and montmorillonite) at a concentration of 500 mg L−1 and four values of ionic strength (0.31, 0.81, 0.02, and 0.01 mol L−1) promoted by the addition of different salts to the solution were used. Clogging tests were conducted with two commercial models of drippers (0.6 and 1.7 L h−1). The deposition zones along the labyrinth channel were analysed using a transparent milli-fluidic system coupled to an optical microscope. Deposition of particles inside dripper labyrinths was observed and this process was strongly influenced by the nature of the clay. The regions of highest particle deposition were vortices zones located in the first baffles of the labyrinths. Kaolinite particles had greater potential of accumulation in the labyrinths than montmorillonite particles. There were fluctuations in the drippers’ discharge during the clogging experiments, but the discharge variations observed were not sufficient to classify the emitters as clogged in any of the test conditions. Clay, as an isolated agent, did not cause full clogging in the emitters evaluated under any of the ionic strength conditions studied. Since particles did not accumulate in the region of the main flow, we suggest that clay particles alone have no potential to cause full clogging of drippers, but may contribute to clogging build-up.

The Food-Energy-Water (FEW) nexus for urban sustainability needs to be analyzed via an integrative rather than a sectoral or silo approach, reflecting the ongoing transition from separate infrastructure systems to an integrated social-ecological-infrastructure system. As technology hubs can provide food, energy, water resources via decentralized and/or centralized facilities, there is an acute need to optimize FEW infrastructures by considering cost-benefit-risk tradeoffs with respect to multiple sustainability indicators. This paper identifies, categorizes, and analyzes global trends with respect to contemporary FEW technology metrics that highlights the possible optimal integration of a broad spectrum of technology hubs for possible cost-benefit-risk tradeoffs. The challenges related to multiscale and multiagent modeling processes for the simulation of urban FEW systems were discussed with respect to the aspects of scaling-up, optimization process, and risk assessment. Our review reveals that this field is growing at a rapid pace and the previous selection of analytical methodologies, nexus criteria, and sustainability indicators largely depended on individual FEW nexus conditions disparately, and full-scale cost-benefit-risk tradeoffs were very rare. Therefore, the potential full-scale technology integration in three ongoing cases of urban FEW systems in Miami (the United States), Marseille (France), and Amsterdam (the Netherlands) were demonstrated in due purpose finally.

[Notes_IRSTEA]105682 [Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI [ADD1_IRSTEA]Gestion intégrée de la ressource et des infrastructures; International audience; In order to reduce irrigation water withdrawal, the European Commission provides grants to farmers for investments in irrigation techniques that save water. However, little is known about the real extent of water savings at plot scale resulting from change in irrigation application equipment or the adoption of scheduling devices in a given agro-pedo-climatic context. The aim of this study was to evaluate irrigation water savings achievable by switching from sprinkler to localized irrigation system or by using soil hydric status probes. For this purpose, we used the French metropolitan context for our case study and compiled all available studies conducted over the past 30 years. A total of 93 records were collected from experimental field trials representative of a wide range of pedo-climatic conditions (25 different sites) and crops (field crops, fruit and vegetable production). Each record represents the water consumption of two different irrigation systems (sprinkler system vs localized system) or two scheduling systems (without soil probe vs with soil probe) at plot scale and is used to assess the water saving made when comparing the most water consuming system to the least consuming one. Results show that water savings are highly variable, ranging from 0% to more than 75% of the initial consumption. They originate in both irrigation technology and management. Their key features are the following. (1) Water savings made with localized systems, when compared to sprinkler irrigation, significantly decrease when the hydric deficit of the cropping season increases and when soil water holding capacity rises. Moreover, they tend to be higher when irrigation is managed with soil probes. (2) Water savings obtained with irrigation scheduling using soil probes (when compared to scheduling without probes) seem, on the contrary, not to be influenced by hydric deficit and soil water holding capacity. The type of soil probe (tensiometric or capacitive) used has no influence on the water savings obtained. (3) Water savings achieved with either localized systems or soil probes result in increased irrigation water productivity and are only marginally influenced by crop type. This frame of reference for irrigation water savings can guide public policies encouraging and financially supporting the implementation of water saving systems, not only on the subject of irrigation devices, but also on irrigation scheduling tools.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI [ADD1_IRSTEA]Gestion intégrée de la ressource et des infrastructures; International audience; Treated wastewater in micro-irrigation is a promising approach that could be used to decrease the pressure on good quality water resources. However, the clogging of such systems due to biofilm development and chemical precipitation constitute a constraint with the use of treated wastewater (TWW) and lead to lower irrigation system performance. The objective of this work is to study the development of biofilm and composition of fouling due to TWW under shear stresses of 0.7, 2.2 and 4.4 Pa detected along micro-irrigation systems. For this purpose, a Taylor-Couette reactor (TCR) was specifically calibrated for the cultivation of biofilm. The analysis of fouling composition samples (organic and inorganic) shows that biofilm tends to develop under the highest shear stress value (4.4 Pa). Precipitation of calcium carbonate in the form of calcite was observed in conjunction with biofilm growth using X-ray diffractometry (XRD) and thermogravimetric analysis (TGA). These results can be used to ascertain the origins of chemical and biological clogging of drippers and fouling of pipes related to reclaimed water- irrigation.

Summarization: Mediterranean-African countries (MACs) face a major water crisis. The annual renewable water resources are close to the 500 m3/capita threshold of absolute water scarcity, and water withdrawals exceed total renewable water resources by 30%. Such a low water availability curbs economic development in agriculture, which accounts for 86% of freshwater consumption. The analysis of the current situation of wastewater treatment, irrigation, and water management in MACs and of the research projects targeted to these countries indicates the need for 1) an enhanced capacity to analyze water stress, 2) the development of water management strategies capable of including wastewater reuse, and 3) development of locally adapted water treatment and irrigation technologies. This analysis shaped the MADFORWATER project (www.madforwater.eu), whose goal is to develop a set of integrated technological and management solutions to enhance wastewater treatment, wastewater reuse for irrigation, and water efficiency in agriculture in Egypt, Morocco, and Tunisia. MADFORWATER develops and adapts technologies for the production of irrigation-quality water from drainage canals and municipal, agro-industrial, and industrial wastewaters and technologies for water efficiency and reuse in agriculture, initially validated at laboratory scale, to 3 hydrological basins in the selected MACs. Selected technologies will be further adapted and validated in 4 demonstration plants of integrated wastewater treatment and reuse. Integrated strategies for wastewater treatment and reuse targeted to the selected basins are developed, and guidelines for the development of integrated water management strategies in other basins of the 3 target MACs will be produced. The social and technical suitability of the developed technologies and nontechnological tools in relation to the local context is evaluated with the participation of MAC stakeholders and partners. Guidelines on economic instruments and policies for the effective implementation of the proposed water management solutions in the target MACs will be developed. Integr Environ Assess Manag 2018;14:447–462. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Presented on

Données complémentaireshttps://static-content.springer.com/esm/art%3A10.1007%2Fs10113-018-1292-z/MediaObjects/10113_2018_1292_MOESM1_ESM.docx; International audience; Climate change and a growing population around the Mediterranean Rim are increasing the need for water and, consequently, the pressure on resources in terms of both quantity and quality. High-quality water should be primarily reserved to drinking water while reclaimed water is an alternative for other usages. A review of situations in Tunisia, Jordan, France, and Italy involving the use of reclaimed water highlights the disparity in national regulations governing this alternative water resource and in its management. On the first hand, the use of recycled water for irrigation can have an adverse impact on public health and the environment, depending on treatment and irrigation practices. On the other hand, it may also represent a new source of water: wastewater should no longer be considered as waste but, rather, as a new resource to be handled in a circular economy-type loop. Current scientific knowledge in agronomic and environmental sciences, as well as in the economic and social sciences, can be integrated and used to lower the associated risk through the effective management of irrigation using recycled water and to address the following questions: (i) How can the time-varying nutrient needs of crops be managed to operate safe environmental reuse within an adapted risk assessment framework? (ii) What socio-economic models can render this integrated approach sustainable? (iii) What treatment systems and irrigation technology can be used to support these ideas and with what information? (iv) What changes in the regulations are needed?

The International Network of Irrigation Testing Laboratories (INITL) undertook a laboratory intercomparison testing exercise of three sets of drippers in the period 2013 and 2014. The four testing facilities that participated in this exercise are based in following countries: Australia, Brazil, France and China. The objective of the testing programme was to compare results from different independent testing facilities to enable individual laboratories identify potential opportunities for improvement of their performances. This would also facilitate the INITL to make proposals for harmonisation of the testing methods. The maximum coefficient of variation, c(v) at the manufacturer's recommended operating pressure of 100 kPa, was found to be 3.76%, which was significantly smaller than the 7% recommended by ISO 9261 [5] as the maximum allowable variation of the flow rate of the test sample. The emitter exponent was determined to be approximately 0.5 which is consistent with results obtained from past studies. At the operating pressure of 100 kPa, it was found that although the average flow rates from the participating laboratories were similar, there was a difference in the dispersion of data. Datasets for the 4 L h(-1) dripper model fitted a normal distribution model, while on the other hand, some datasets for the 2 and 8 L h(-1) dripper models were not normally distributed. A higher dispersion of measurements can be interpreted as a higher instability of the testing conditions. The variance for the 2 L h(-1) dripper model was found to be homogeneous, while non-homogeneous for the other two models. The latter implies that at least one of the laboratories presented an uncertainty of measurement significantly different from the others. The measurement uncertainty undertaken in this study demonstrated that there were opportunities to improve the measurement process. Recommendations and suggestions for harmonisation of test procedures and improvements in individual laboratories are also identified in this paper. Refereed/Peer-reviewed

National audience; The microtube are emitters of small diameter and there has recently been developed a new type of microtube called of microtube with multiple outputs (MMO) and consists of a pressure regulator microtube attached to a connector with radial arrangement from where are derived six emitters microtubes. The microtubes are highly susceptible to clogging because of its small diameter. The aim of this study was to evaluate the sensitivity of the microtubes to obstruction by physical agents. We used the methodology proposed by Institut National de Recherche en Sciences et Technologies pour l'Environnement et l'Agriculture (IRSTEA) to evaluate the sensitivity of the microtubes to obstruction. In addition, we used the computational program ANSYS Fluent for better visualization of areas more conducive to obstruction of the MMO. Microtubes were assayed with a diameter of 1.074 mm and microtubes with multiple outlets operating with inlet pressure of 5 m. The MMO is less sensitive to clogging than the individual microtubes with internal diameters of 1.074 mm. The use of ANSYS Fluent program identified critical areas in the connector that can contribute to the obstruction of the emitter.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI [ADD1_IRSTEA]Gestion intégrée de la ressource et des infrastructures [ADD2_IRSTEA]Équiper l'agriculture; International audience; Emitter clogging is a major problem in microirrigation systems, which may result from the isolated or combined effects of physical, chemical, and biological agents. Clogging caused by suspended solid particles is the most common plugging form of emitters. Water quality and emitter geometry are key aspects in clogging processes. Any suitable test procedure to assess the sensitivity of drippers to clogging should take into account the predominant factors that influence clogging and must reproduce the field conditions. This research set out to assess the performance and suitability of a laboratory clogging test procedure in order to validate a methodology and to provide scientific results that may support the standardization of a clogging test method. The evaluated methodology has been used by the IRSTEA laboratory since 1974 (Platform of Research and experiment on Science and Technology for Irrigation - PReSTI, formerly LERMI) and its contents are currently being discussed by the ISO TC23/SC18 committee. The aim is to define a standardized testing protocol to evaluate the sensitivity of emitters to clogging due to solid particles. Replications analyzing the clogging resistance of four models of emitting pipes were carried out in a laboratory. The clogging test procedure enabled an accurate assessment of the combinations of concentration and size of particles that caused clogging in each model of dripper. However, a significant variability in degree of clogging was identified when the results of replications for each model of dripper were compared. Several requirements, concerns, and improvements related to the clogging test protocol were discussed.

An automated system for indoor testing of irrigation sprinklers was developed and evaluated. The system was designed to test single sprinklers with jet lengths up to 18 m. The tests involve the use of 36 collectors (catch-cans) spaced at 0.5 m intervals along the jet radius. A single pressure transducer coupled to a manifold equipped with solenoid valves was employed to sequentially scan the water level in each collector. Radial application rates were determined based on water level measurements. Results obtained using the automated system were compared with those obtained using manual operation using mass measurements. Uncertainty analysis of the manual method was compared with the automated system. The automated system was found to be as reliable as the manually operated system for testing sprinklers. Although minor differences in the application rates measured by the two methods were detected, they did not cause appreciable differences in the distribution uniformity indicators used. The results presented will provide useful baseline for uncertainty analysis in irrigation sprinkler testing.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI [Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI; International audience; Micro-irrigation with treated wastewater has the potential to be the most efficient irrigation technique, especially in water scarce areas. Its main disadvantage is the high sensitivity of the drippers to clog. This study focused only on the chemical precipitation mechanisms. In a batch chemical process in parallel with PHREEQC software, two temperatures (22 and 55°C), four pH (8, 8.5, 9 and 9.5) and CO2 partial pressure were tested. The aim was to analyze the quantity of precipitates and their crystalline nature and calculate the effects of these factors on the behavior of dissolved chemical elements in treated wastewater to be able to validate and calibrate a geochemical software in order to predict chemical precipitation. The amount of precipitate increases by increasing pH and temperature. Precipitates were analyzed using thermo gravimetric analysis (TGA) and X-ray diffraction (XRD). Calcium carbonate (CaCO3) in the form of calcite was found to be the predominant precipitate. Experimental and model results showed that the saturation index (SI) of calcite was found to be the factor that most frequently affected calcite precipitation. Calcite SI is pH, temperature and CO2 partial pressure dependent. In the case of irrigation, water equilibrium with atmospheric CO2 minimizes precipitation of calcite.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI [Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI; International audience; Experiments were carried out to investigate pipe material impacts on biofouling, at high effluent concentration levels and under controlled hydrodynamic conditions. Two velocities (0.4 and 0.8 m s-1) were used to monitor biofilm growth on polyethylene (PE) and polyvinylchloride (PVC) pipe walls, respectively. These conditions were established based on wastewater irrigation practices. A decrease in biomass is observed after 49 days of experiments for both velocities and may be related to biofilm detachment. Biofilm growth is greater at 0.8 m s-1. For both velocities, PVC is less sensitive to biofilm growth than PE. Pipe straightness plays a primary role in biofilm growth control. This effect is more significant than pipe surface characteristics (roughness, hydrophobic/hydrophilic properties).

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI; International audience; The International Network of Irrigation Testing Laboratories (INITL) undertook a sprinkler intercomparison testing exercise to generate data for an objective comparison of the performances of the different facilities and identify opportunities for further improvements.Three impact sprinklers were tested in four laboratories in accordance with established standards. The plots of flow rate-pressure profiles were found to be consistent, and correlated to those obtained from previous studies. Although there were slight variations in the measured flow ratedata, the mean flow rates at each pressure level were the same for the three sprinklers, and the shapes of the radial distribution profiles were similar. The deviations of reconstituted flow rates (from the measured) of at least two tests in each facility were found to exceed the recommendedlimit. The sprinkler software developed by INITL was found to have a good correlation with a related commercial softwareprogram.

International audience; Treated wastewater reuse (TWWR) offers a promising solution for farm crop and turf irrigation while also mitigating the environmental pressures resulting from effluent disposal in the environment. Most attention is devoted to ensuring that treatments are safe for human health. Nevertheless, the treatment may be incomplete or some pathogens resulting from biofilm development may be dispersed through the system. Therefore, end-users must take specific precautions and implement practices to prevent any unintended dispersal of contaminants transported by the water, in particular when using sprinkler irrigation practices. To generate data to evaluate dissemination hazards, and thereby facilitate risk calculation, a sprinkler was operated in (windy) field conditions and the wetted area drift as well as the transport of small particles downwind was measured within a perimeter 4 times the sprinkler range. The volumes collected at such distances on the ground and along the wind axis remained below 0.5 mLm-2 h-1, and below 4 mLh-1 perm2 of vertical section, for winds of 5 ms-1, and below 0.25 and 1.4 mLh-1 per m² of vertical section for winds of 3 ms-1. The measurement method, based on the use of fluorescent dye, is proposed along with an empirical model that can be used to estimate the volumes of potentially contaminated water that can escape from the wetted zone under wind influence for the specific sprinkler used.

A distributional semiempirical model for the simulation of spatial distribution of water application under center pivot sprinklers has been developed by the writers. This method describes the probability of water application for a sprinkler using a combination of beta functions. The calibration of this model has been undertaken using laboratory tests conducted in controlled conditions and then in windy conditions. The parameters calibrated are listed. The minimum number of tests needed for calibration has been estimated. The model used can be calibrated from one test in controlled conditions and three or four tests in windy conditions covering the range of usual wind speeds. Validation should be performed using at least two more infield tests. This simulation model of spatial water distribution under sprinklers of center pivot will thereafter be used to simulate the distribution of water under a typical pivot machine.

A model describing the application pattern produced by a single sprinkler is proposed. Based on calibrated statistical distributions and free from any ballistic consideration, this model uses a mixture of beta probability distributions in which parameters are first estimated with water application data measured in zero wind condition. Data measured in field conditions are then used to assess the wind effect on the shift of the center of gravity of the irrigated area, on the range of the sprinkler in various directions, and on the values of the beta distributions' parameters. The computation of the water application amounts at any point of the irrigated area is finally resolved in the use of a single equation, which can be easily implemented in a software package to simulate application patterns under a series of sprinklers attached to a center pivot or moving lateral irrigation machine.

Ageing of drip irrigation systems due to clogging of emitters is considered the largest maintenance problem in microirrigation and this problem is enhanced in subsurface irrigation systems. Whatever the source of the clogging problem, a methodology for early detection of clogging in the field can be useful in decision-making about deploying cleaning processes (flushing or injection of chemicals) and avoiding replacement of laterals. This work presents a methodology for simulating clogging conditions able to reproduce the effects of clogging on pressure profiles, head loss, and emitters flow rate distribution along a single levelled lateral with constant inlet pressure. This methodology was validated by several experiments conducted under controlled conditions of clogging induced by changes in the flow rate of emitters. The effects of clogging intensity and position on hydraulic parameters of a single lateral were analysed in detail and aspects relating to pressure, head loss, and flow rate measurements were discussed. For a given lateral set-up, it is possible to draw a chart relating flow rate and head loss for various levels and positions of clogging. Assuming that measurements of head loss and flow rate are available, this diagram enables immediate estimation of the level and location of clogging, which is useful for deploying maintenance routines. Finally, a protocol was proposed to detect the level of clogging and estimate its position along a levelled lateral under constant inlet pressure. Although constant lateral inlet pressure is atypical in large agricultural settings, it may occur in greenhouse or experimental settings.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI; Le recyclage des eaux usées représente une solution pour faire face à la demande croissante des ressources hydriques pour l’irrigation agricole. Mais leur réutilisation pose des problèmes de sécurité, de réglementation et bien sûr de techniques adaptées, que cet article nous propose de mieux comprendre.

A simulation model of rainfall under center pivots was used to elevate center-pivot testing procedures. The model calculates rainfall parameters such as weighted mean and uniformity coefficient for various scenarios including the case of a voluntarily disrupted machine. Observed variations in rainfall parameters suggested modifications to standard procedures in order to improve accuracy., Un modèle de simulation de précipitations sous des pivots centraux a été utilisé pour élever les procédures d'essai des pivots centraux. Le modèle calcule les paramètres de précipitations comme le coefficient moyen pondéré et le coefficient d'uniformité pour différents cas de figure y compris celui d'une machine volontairement en panne. Les variations observées dans le domaine des paramètres de précipitation ont suggéré des modifications des procédures standards afin d'améliorer la précision.

During sprinkler irrigation, the water wind drift and direct evaporation losses can vary very widely: from 2% to 50 %. The object of this thesis project is to distinguish the two forms of these losses and to know how they are generated. We have been able, thanks to volumetric measurements, to assess the global losses to a maximum value of 23% registered under very hard climatic conditions. We have carried out under controlled conditions, by way of electric conductivity, some measurements of the direct evaporation losses: the maximum value registered was about 5%. This measurement allowed us to calibrate a statistic model able to assess the rate of this kind of losses under some climatic conditions. Using a CFD tool, the modelling of global losses, through a combined Eulerian and Lagrangian approach, gave us some results which are in agreement with measurements. We computed a very small direct evaporation rate on the big droplets: less than 4% of the droplets which are bigger than 1 mm. However, the smallest ones (which are smaller than 150 µm) can be totally evaporated and/or drifted outside the irrigation zone. Thanks to this modelling, we are able according to the climatic conditions to compute the water global losses and to distinguish the amount of every part: the drift and the direct evaporation losses. The droplets path is determined according to their size, so we can conclude that the two models (statistical and CFD ones) are correlated to the PDF of the droplets cloud. That's why, an accurate knowledge of the droplets initial size is needed to well assess the water global losses (particularly the drift losses which constitute the biggest part) and to control them.; Lors de l'irrigation par aspersion, les pertes par évaporation et dérive peuvent varier dans une large plage allant de 2% à 50% . Ce travail vise à connaître d'une manière plus précise cette perte, et à en connaître les formes et les mécanismes. Les mesures effectuées par bilan de volume ont permis d'évaluer la perte globale à un maximum de 23% sous des conditions climatiques extrêmes; la part de la perte par évaporation directe, estimée par des mesures de conductivité électrique en conditions contrôlées, ne représente quant à elle que 5% au maximum. Un modèle statistique issu de ces résultats permet de connaître le taux de perte en fonction des conditions climatiques et du trajet des gouttes. La modélisation numérique de cette perte moyennant des approches lagrangienne et eulérienne a donné des résultats en accord avec les mesures enregistrées: l'évaporation directe constitue une faible proportion (inférieure à 4%) sur les gouttes de taille supérieure à 1mm. Cependant les plus petites parmi elles (de tailles inférieures à 150 µm) sont susceptibles de s'évaporer entièrement et le cas échéant de dériver en dehors de la zone d'arrosage. Les résultats de la modélisation numérique permettent, à partir de la connaissance des conditions climatiques, de distinguer la dérive de l'évaporation directe en fonction de la taille des gouttes. Etant donné que le trajet des gouttes est dépendant de leur inertie, on conclut que les deux modèles statistique et numérique sont directement corrélés à la granulométrie des gouttes, d'où la nécessité de bien la connaître, et de la maîtriser pour mieux contrôler les pertes d'eau dans l'air, et notamment la dérive qui constitue la plus importante part. Cette thèse en mécanique des fluides est appliquée à l'irrigation par aspersion, elle comporte deux volets assez différents mais qui se complètent: la mécanique des jets d'eau et leur thermodynamique d'une part, et l'évaporation des gouttes et la bioclimatologie de l'environnement d'autre part.