How to monitor a large-scale surface-flow constructed wetland with minimal disturbance?

Abstract : The AZHUREV surface-flow constructed wetland is a large-scale demonstration wetland built at the outlet of the Grand Reims (France) wastewater treatment plant (WWTP). Three 20,000 m 2 basins (rectangular shape with different depth distribution within each basin) have been created: the initial vegetation (mainly P. australis, S. lacustris and G. maxima) density was also different in each basin. Their aim is to polish a part of the treated wastewater (250 m 3 /h) from the Grand Reims WWTP, as well as to treat part of the Grand Reims stormwater. The basic monitoring of the wetlan is routinely done via sampling at the inlet and the outlet of each basin. However this does not provide information on the spatial distribution of the pollution in the basins, or of temperature and dissolved oxygen. Photographs are routinely taken from the shore but, due to the size of the basins, they do not provide detailed information on the development of the vegetation. To monitor the basins without disturbance, two drones are used:-An aquatic drone (Spyboat by CT2MC) which is remotely driven from the shore. It is fitted with a dissolved oxygen probe and a temperature sensor to collect data 10 cm below the surface. It can also collect liquid samples by means of a peristaltic pump. The superstation in oxygen observed with the aquatic drone in spring is correlated with the increase of the photosynthetically active solar radiation and the development of algae in the basins. Later in the year, anaerobic zones are detected under the duckweed-covered surface. The aquatic drone is more difficult to operate when the duckweed layer is becoming thick or when the surface is frozen.-An aerial drone (type DJI-S900), to better locate dense vegetation beds (especially those of G. maxima) and verify their development. Isolated plants cannot be located easily by the aerial drone. Satellite imaging (Landsat 8 OLI images obtained from https://glovis.usgs.gov) is also tested. The satellites images are collected every two weeks but cannot be used in presence of clouds. In spite of their 30m resolution, they allow to monitor the variation with respect to time of the vegetation, especially the development of duckweed on the wetland surface. The poster will present the latest 2019 results obtained with these tools and discuss further their advantages and disadvantages.
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Poster communications
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https://hal.univ-lorraine.fr/hal-02334758
Contributor : Marie-Noëlle Pons <>
Submitted on : Tuesday, October 29, 2019 - 5:15:47 PM
Last modification on : Thursday, October 31, 2019 - 1:18:35 AM

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  • HAL Id : hal-02334758, version 1

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Marie-Noëlle Pons, N Maurice, Maïa Durozier, Christophe Gauthier, Vincent Dutreuil, et al.. How to monitor a large-scale surface-flow constructed wetland with minimal disturbance?. ILTER-OSM 2019, Sep 2019, Leipzig, Germany. ⟨hal-02334758⟩

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