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| Titel |
Phyto-dehydration of confined polluted sludge: impacts on C-storage and heavy metal immobilization in plant tissues |
| VerfasserIn |
Dario Liberati, Paolo Sconocchia, Anna Ricci, Giovanni Gigliotti, Chiara Tacconi, Paolo De Angelis |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250154530
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| Publikation (Nr.) |
 EGU/EGU2017-19639.pdf |
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| Zusammenfassung |
| Transpiration of plants can be used to control or remove water in artificial basins containing
polluted flooded sediments (phyto-dehydration), with the aim to reduce the risk of
environment contamination due to water/sediment spillage. At the same time plants can
reduce the risks associated to the pollutants, reducing their mobility by the adsorption in the
rhizosphere, uptake and accumulation in tissues, and providing organiccompounds
contributing to bind heavy metals.
We tested, at pilot scale, a phytodeydration approach to be applied to a storage pond
containing sludge with high zinc and copper concentrations (3200 and 1000 µg/Kg,
respectively). The sludge derives from the biodigestion of pig slurries, and for most of the
year is covered by a water layer due to rainfall. The phyto-dehydration approach was
tested in a two years long mesocosm-scale experiment. Inside the mesocosms we
maintained the same sludge/water stratification observed in the pond; the helophyte
species Phragmites australis was planted over a floating frame inside half of the
mesocosms. Mesocosms with P.australis and control mesocosms without plants, were
monitored during the test to assess the water consumption, CO2 and CH4 gas exchanges
and plant functioning. At the end of the second year we analysed the changes on
the carbon pool of the sludge and the immobilization of heavy metals in the plant
tissues.
After two years, the total organic carbon content of the sludge has been reduced in the
control mesocosms, while in the P. australis mesocosms remain close to the initial values.
Zinc and copper immobilization in the plant tissues, was characterised by: a very low
concentration of zinc (5 µg/kg ) in leaves, intermediates values in culms and rhizomes (49
and 30 µg/kg) and higher values in roots (222 and 114 µg/kg).
In conclusion, in addition to the reduction of the sludge spillage risks, the
phyto-dehydration approach based on P. australis reduced the carbon loss of the
sludge, and triggered at the same time a phytostabilization process that reduce the
mobility of zinc and copper, without risk of input of these metals to the food chain. |
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