Pollution de l'eau

Résumé

vignette|Les détritus de type déchets ménagers sont souvent indicateurs de pollutions (métaux lourds, micro-organismes) posant des problèmes de santé publique, notamment dans les régions où les eaux de surfaces sont utilisées pour la boisson, la lessive, la vaisselle, se laver, faire la cuisine, etc.). vignette|Les pollutions les plus spectaculaires (par des sels de fer ici) ne sont pas toujours les plus toxiques, mais de fortes concentrations d'un produit non réputé toxique (fer, sel par exemple) peuvent faire disparaître la plupart des formes de vie. vignette|Exemple d'espèces indicatrices de très forte pollution organique de l'eau. Il s'agit de bactéries filamenteuses. En aval d'abattoirs ou de papeteries ne disposant pas d'un dispositif suffisant d’épuration des eaux, et en climat tempéré, elles comptent parmi les espèces les plus résistantes à la pollution organique (avec une petite sangsue brune, des larves de chironome et les tubifex). vignette|Les berges « sous le vent » recuei

Source officielle

https://fr.wikipedia.org/wiki/Pollution_de_l'eau

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BIOPHYSICAL CONTROLS ON EVAPOTRANSPIRATION: NUMERICAL MODELS AND EXPERIMENTAL OBSERVATIONS

Federico Croci

Water and food are basics of human life, unfortunately climate changes and water pollution have reduced the amount of water available for human uses. In this context the study of the hydrologic cycle is becoming of growing importance in order to optimize the anthropogenic exploitation of water resource. Evapotranspiration is the term used to describe the part of the water cycle which removes liquid water from an area with vegetation into the atmosphere by the processes of both transpiration and evaporation. Evapotranspiration is an important part of the hydrologic cycle because it represents a considerable percentage of water losses in watersheds. This process is also one of the main consumers of solar energy at the Earth's surface. The estimation of evapotranspiration it is of great importance for agriculture and water resources management, for example, by knowing the rate of water loss from a region, farmers will be better placed to efficiently manage the irrigation strategies. The rate of evapotranspiration at any location on the Earth's surface is controlled by several factors such as energy availability, humidity gradient, wind speed immediately above the surface, water availability, type of vegetation, stomatal resistance and soil characteristics. The problem of estimating evapotranspiration has been widely studied. During the past several decades, different approaches have been proposed and many formulas are available in the literature to fulfill this task. The complexity of the phenomena and its great variability all over the world make difficult to find a universal and robust method for the evapotranspiration prediction and estimation. Evapotranspiration can be obtained by many estimation methods. Some of these methods need many weather parameters as inputs while others need fewer. Factors such as data availability, the intended use, and the time scale required by the problem must be considered when choosing the evapotranspiration calculation technique. The Penman-Monteith equation was derived from the classic Penman equation adding to the terms already considered in the Penman formulation (aerodynamic resistance and energy balance) the canopy resistance. This approach requires many meteorological data, such as maximum and minimum air temperatures, relative humidity, solar radiation, and wind speed. If some of these data are not available, alternative techniques have been developed to overcome this drawback. However, this estimations of meteorological data affect the quality of the result, alternatively, in such cases other simpler methods may be used. The Penman-Monteitu equation is assumed to be the most reliable because is based on physical principles and because it considers all the climatic factors, which affect evapotranspiration.

2013

Chargement

Porto Marghera. A new productive Lanscape

Nicola Zanin

Fusina is a particular area of Porto Marghera, Venice mainland industrial area, different from any other areas inside the industrial compound. It's situated in the southern border, the most close to the Veneto coun- tryside. This area was one of the last to turned from rural to agricultural at the beginning of the 60's, with more reprises in the following years. The rural landscape characterized by woods, countryside and isolated vernacular buildings turned into an industrial landscape characterized by infrastructures, factories, vapor and ash. ; The heavy industrialization deeply compromised the fragile lagoon ecosystem and lead to a diffuse problem of soil and water pollution. The project aim to transform Fusina in a big machine for the de-pollution where can be tested experimental techniques, fast and slow method of cleaning of the soil. The masterplan try to improve the industrial grid of roads and factory, defining distinct parcels and trying to preserve most important recycling and energy factories still active in the area and reconverting some of them into a research centre or laboratories. The program of my project is a thermal desorption for the cleaning of the soil and a thermal plant for the production of energy through biomass.

2016

Chargement

The Doubs river is an ecosystem-rich river which is threatened by several anthropic activities. The three dams placed in the river as well as the discharge of pollutants contribute to the degradation of its natural habitats. The city of La Chaux-de-Fonds is directly concerned by this issue. The combined sewer overflow (CSO) waters generated by the city discharge in la Ronde, an affluent of the Doubs. These waters represent a potential threat to the Doubs water quality, this is why the authorities of La Chaux-de-Fonds need to take measures to limit the impacts of these waters in the natural environment. These measures have to be taken without causing excessive costs. Several solutions have been considered according to the objectives set during the development of the « plan d’évacuation des eaux (PGEE) » of the city. The implementation of a constructed wetland was the selected solution. This system is widely used in a number of European countries and especially in France, but is not yet much developed in Switzerland. Topographic and design constraints have lead the choice of a vertical flow constructed wetland. Its technical feasibility has been deeply studied. The design of the constructed wetland has been examined using the simulation tool Orage (which is currently in phase test in the IRSTEA research institute in Lyon). A second tool, the Rebeka software, allowed to determine the impact of the CSO water on the water quality of the Doubs. The STORM approach helped to integrate these impacts in the design of the system from the beginning of the the project. The costs of the project are detailed in investment costs for the building of the wetland and operation costs which represent essentially functioning and maintenance costs. The treatment system consists of three planted filters which operate in parallel. Simulation results demonstrate that the objectives of the project are fulfilled. The installation has a removal efficiency of 29% on ammonium, 44% on COD and 95% on TSS. The initial investment is 3.6 million Swiss francs. This system offers a solution to resolve pollution issues originating from the CSO waters of the city of La Chaux-de-Fonds with a reasonable initial investment.

2016

Chargement

BIOPHYSICAL CONTROLS ON EVAPOTRANSPIRATION: NUMERICAL MODELS AND EXPERIMENTAL OBSERVATIONS

Federico Croci

2013

2016