NITROGEN AND DISSOLVED CARBON BALANCES IN THE AZHUREV CONSTRUCTED WETLAND

Abstract : The Azhurev horizontal-flow constructed wetland is a large-scale demonstration wetland built at the outlet of the Grand Reims 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 wetland has been operated since July 2017. Flowmeters have been installed at the inlet and the outlet of each basin, as well as conductimeters and temperature sensors. Sampling campaigns have been organized on a monthly basis: the samples have been collected at the inlet and exit of each basin as well as in the basins with an aquatic drone. They have been analysed in terms of nitrogen species (total dissolved nitrogen, nitrates, nitrites, ammonia) and dissolved inorganic and organic carbon. The dissolved organic matter has been further characterized by optical methods (synchronous fluorescence and UV-visible spectroscopy). Plants have been collected and their carbon and nitrogen content has been determined. There is no infiltration from the basins to the aquifer, as evidenced by the hydraulic balance. The results obtained after more than one year of operation show a global nitrogen removal rate of 50% (equivalent for nitrates and ammonia). An increase of the dissolved organic carbon has been observed between the inlet and the outlet in summer and fall: this is due to anaerobic decomposition of aquatic plants underneath a thick layer of L. minor, which has gradually covered the basins. In November 2018, a large maintenance of the site has been set up with plant cutting and removal, in order to promote vegetation development in spring. The presentation will describe the complete carbon and nitrogen balance over the two years of operation of the wetland and compare the basin efficiency in function of the vegetation. BIO: N. Maurice is a Ph.D student with a soil and water remediation background.
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Conference papers
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https://hal.univ-lorraine.fr/hal-02334762
Contributor : Marie-Noëlle Pons <>
Submitted on : Tuesday, October 29, 2019 - 5:07:18 PM
Last modification on : Monday, November 11, 2019 - 1:25:11 AM

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  • HAL Id : hal-02334762, version 1

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Maïa Durozier, Cécile Pochet, Grégoire Jost, Nouceiba Adouani, Marie-Noëlle Pons, et al.. NITROGEN AND DISSOLVED CARBON BALANCES IN THE AZHUREV CONSTRUCTED WETLAND. WETPOL-2019, Jun 2019, Aarhus, Denmark. ⟨hal-02334762⟩

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