Amélioration de la qualité microbiologique des effluents secondaires par stockage en bassins

Microbiological quality improvement of secondary effluent by reservoir storage. Storing secondary effluents is of particular interest for water resource management. It constitutes further treatment which reduces the microbial contamination of water to a level where it can be used for the irrigation of all crops, without restriction. The storage of treated wastewater takes place during the winter, ensuring that such a resource is not lost and enabling a larger area to be irrigated during the dry season, thereby increasing agricultural production. Storage trials in reservoirs were conducted in north-eastern Tunisia. Their objective was to determine the length and conditions of secondary effluent decontamination as well as the impact of seasonal storage on water quality. The results indicate that the decontamination of effluents slows down with increased reservoir depth. For a depth of less than 150 cm, a reduction of fecal coliforms in the order of 3 log units is attained in 3 days when the average temperature of the water ranges from 22 to 25 degrees C; when this temperature is between 25.5 and 28 degrees C, the same reduction takes 8 days. Below 20 degrees C, decontamination is considerably reduced: for a mean water temperature ranging from 12.5 to 18 degrees C, the reduction of fecal coliforms reaches 3 log units only after a retention time of 17 days in the reservoir. Seasonal storage from 2 to 7 months does not affect the bacteriological quality of water: after decontamination, no proliferation of bacterial indicators occurs during storage

Effect of water stress on growth, water consumption and yield of silage maize under flood irrigation in semi-arid clilmate of Tadla (Morocco)

The field study of crops response to water stress is important to reduce agricultural water use in areas where the water resources are limited. This study was carried out during two growing periods of 2009 and 2010 in order to study the effect of water stress on crops growth, water consumption and dry matter yield of silage maize supplied with flood irrigation under the semiarid climate of Tadla in Morocco. Four to five irrigation treatments were applied at the rates of 100, 80, 60, 40 and 20% of ETc of maize. Soil water status, crop growth, leaf area index and above-ground biomass were measured. Results showed that growth dynamic of maize passes by three distinct phases: exponential phase, linear phase and a final phase. The irrigation deficit accelerates the senescence of the sheets and reduces the leaf area index. The maximum values of this parameter reached at flowering under the full irrigation treatment (100%ETc) are 5.1 and 4.8 in 2009 and 2010 respectively. Dry matter yields varied from 5.3 t/ha under T4 (40%ETc) to 16.4 t/ha under T1 (100% ETc) in 2009 whereas in 2010, it oscillated between 3.9 t/ha under T5 (20%ETc) to 12.5 t/ha under T1 (100%ETc). The actual evapotranspiration under T1 (100%ETc) was 478 mm and 463 mm in 2009 and 2010 respectively. According to the averaged values of two years, linear relationships have been evaluated between dry matter yield and water consumption ETa. Yield response factor (ky) for the silage maize for all growth season was 1.12

Does fertilization practices increase residual nitrate nitrogen in soil irrigated with treated wastewater? An experimental trial on maize

Treated wastewater has significantly improved DM yield compared to ground water. The form of nitrogen provided by the water was determinant in drawing yields. Irrigation with ground water (where nitrogen is as nitrate) induces a faster migration of nitrogen at depth. In contrast, using treated wastewater (where nitrogen is as ammonium), resulting in a relative distribution of the remaining nitric smaller in the lower profile and therefore higher in the surface, especially after the second year (2010). In addition, the relative distribution of nitrates in the soil surface is even more important in the presence of organic manure. All happens as if a certain amount of ammonium provided by treated wastewater is retained in the organic compounds of manure. Yields were significantly lower in irrigation with treated wastewater in the second year and especially when fertilization was given in additional. If the soil can be used for storage of the nitrogen supplied by the treated wastewater during the first year of irrigation (24 kg N-NO3/ha before irrigation to 115 kg N-NO3/ha after irrigation), to the second year the capacity drops (to 64 N-NO3/ha) and a significant increase in nitrate leaching occurs. Therefore, unlike the contribution of manure that seems enrich the topsoil nitrate nitrogen, at least during the first campaign, mineral fertilization unreasoning causes faster migration of nitrogen at depth

A computational framework for complex disease stratification from multiple large-scale datasets.

BACKGROUND: Multilevel data integration is becoming a major area of research in systems biology. Within this area, multi-'omics datasets on complex diseases are becoming more readily available and there is a need to set standards and good practices for integrated analysis of biological, clinical and environmental data. We present a framework to plan and generate single and multi-'omics signatures of disease states. METHODS: The framework is divided into four major steps: dataset subsetting, feature filtering, 'omics-based clustering and biomarker identification. RESULTS: We illustrate the usefulness of this framework by identifying potential patient clusters based on integrated multi-'omics signatures in a publicly available ovarian cystadenocarcinoma dataset. The analysis generated a higher number of stable and clinically relevant clusters than previously reported, and enabled the generation of predictive models of patient outcomes. CONCLUSIONS: This framework will help health researchers plan and perform multi-'omics big data analyses to generate hypotheses and make sense of their rich, diverse and ever growing datasets, to enable implementation of translational P4 medicine

Sustainability and optimisation of treatments and use of wastewater in agriculture.

Rapport Final Economical study INCO-D

Optimisation de la fertilisation azotée de cultures industrielles légumières sous irrigation

Optimisation of fertilisation for irrigated vegetables. Experiments were performed over four years, testing five cultivations to optimise mineral nitrogen fertilisation when irrigation with wastewater occurs. The experimental site was located inside an irrigated perimeter around the agro-food industry Hesbaye Frost, producing frozen vegetables, in Belgium. Depending on the crop rotation adopted by the farmer, four vegetable cultivations (spinach, bean, carrot and broad bean) and one cereal (winter wheat) were tested. Because of the time required for implementation of the experiment and meteorological conditions, the irrigation factor was not tested for spinach (1999) and wheat (2000) cultivations. The two experimental factors were three fertilisation levels, with comparison to a reference without any mineral nitrogen supply, and irrigation with or without wastewater. These factors were assessed for their impacts on crop yields and mineral nitrogen residues in the soil after harvest. The three vegetable cultivations of bean, carrot and broad bean were irrigated and systematically presented statistically higher yields with wastewater irrigation supply than without. The fertilisation factor also significantly improved all the yields, or protein rate for cereal cultivation, except for carrot and broad bean where differences were not significant, even for the zero fertilisation rate. The nitrogen residues in the soil after harvest were acceptable and regular as long as the fertilisation advice was not exceeded; the maximum fertilisation level tested, 50% higher than the recommendation, systematically left unacceptable nitrogen residues in the soil, harmful for the environment. Mainly located on the top surface horizon layers, thenitrogen residues could be held back by a catch crop classified as a nitrogen trap, with the condition to be set on late summer, with fall being considered as too late to have any influence to avoid nitrogen leaching. For all fertilisation levels, nitrogen residues were too high for the broad beans cultivation because of the phenomenon of surface mineral nitrogen release, due to meteorological conditions and the wastewater high nitrogen load brought by irrigation. The nitrogen residues under conditions of no irrigation were higher than under irrigation. Irrigation allowed better nitrogen solubility, easier for uptake by the plants and thus left fewer residues in the soil

Concepts d'efficience et de productivité de l'eau (synthèse bibliographique)

Water efficiency and productivity concepts. A review. Water efficiency and productivity indicators are used in many scientific disciplines, usually to account for water losses that occur during its use, or products generated per unit of water consumed. The interpretation of these indicators is very diverse in the literature. However, the majority of definitions consider water efficiency as a measure of the effectiveness of irrigation, and view water productivity as a measure of the effectiveness of the physiological processes of both biomass production and crop yield formation, linked to the actual consumption of water by the crops. Thus, the consensus seems to be for water application efficiency (Ea) to be considered as the ratio of actual evapotranspiration to the water applied and productivity as the ratio of yield to actual evapotranspiration. The point of divergence relates fundamentally to the understanding of the constituent expressions of productivity (PE, product/"water consumed") and efficiency of water application (Ea, "water consumed"/"applied water"). Indeed, the term "water consumed" is referred to variously by several authors as "actual evapotranspiration", "gross irrigation plus rainfall", "evapotranspiration plus water lost at the plot but beneficial to other users", etc. Furthermore, while providing more details on the concepts of efficiency and water productivity, this review shows that the factors affecting these indicators have not yet been sufficiently elucidated. Thus, one of the axes of investigation could be to model the application efficiency of water firstly, according to water management practices and secondly, in terms of productivity levels in relation to the crop establishment period

Citerne d'eau de pluie et effet sur le débit à l'exutoire du bassin versant de l'Orneau dans la région de Gembloux (Belgique)

Rainwater storage and effect on flow rate at watershed outflow. This study participates to the quantitative balance of rain water domestic use. It aims towards an optimal design of rain barrels volume, the feasibility of soil infiltration techniques with excess of water and the impact assessment of rain barrel on the decrease of peak flow in a pilot rural watershed of 9 km², considering the chronology of precipitation events. The parameters that are considered are the roofs area, the number of inhabitants in the house, the average daily rainfall water consumption, and the local pluviometry. In order to design the infiltration structure associated with the rain barrel, the volume of rainfall excess from the rain barrel needs to be evaluated. Afterwards, the infiltration structure may be dimensioned according to the soil infiltration characteristics. We assume that 75 l, out of the 115 l daily consumed by each inhabitant, are coming from the rain barrel and the remainder (40 l) is drawn from the drinking water distribution network. Calculations are carried out for roofs of 100, 135, 170 and 200 m², for a consumption of water ranging between 150 and 1,150 l per day per house and for rain barrels of 5, 10 and 20 m³. It appears that if correctly designed private rain barrel allows an opportune water use in households, the effect on flood reduction is, however, limited considering the relative low importance of the collecting surface (1.3% of the watershed surface)

L'isotope stable 15N et le lysimètre, des outils complémentaires pour l'étude de la lixiviation de l'azote dans les sols agricoles

Stable 15N isotope and lysimeter, complementary tools in order to study the nitrogen leaching in agricultural soils. Stable 15N was used in lysimetric trials conducted with the aim to study nitrate leaching of agricultural soils. At Gembloux, a rate of 200 kg N.ha-1 as 15NH4 15NO3 with an isotopic abundance of 2.161 At%15N was applied in two lysimeters before a spinach crop, followed by beans and winter wheat; in the first lysimeter, total recovery by crops was less than 39.8% while in second lysimeter, recovery was 62.2%. Concentrations of N-NO3 - in leached water were always higher in lysimeter 2 than lysimeter 1, probably due to less microbial immobilization of nitrogen. At Remicourt and Omal, a simulated mineral residue of 150 kg N.ha-1 (rate of 15NH4 15NO3 applied in autumn) has completely disappeared from the soil profile (0-90 cm) already in July of the following year. At Omal, a winter crop has recovered no more than 9% of nitrogen rate applied in autumn. Measurement of N-NO3 - concentration in leached water has shown clearly higher levels at Remicourt (even more than 70 mg N.l-1 probably caused by an application of high rate of compost rich in nitrogen) than is Omal. Stable 15N isotope could not be analyzed in leaching water probably due to a leak of sensitiveness of the analytical equipment