Use of wood and cork in biofilters for the simultaneous removal of nitrates and pesticides from groundwater

Autor: Mònica Escolà Casas, Miriam Guivernau, Marc Viñas, Belén Fernández, Rafaela Cáceres, Carme Biel, Víctor Matamoros
Přispěvatelé: Producció Animal, Producció Vegetal, Sostenibilitat en Biosistemes, Protecció Vegetal Sostenible
Rok vydání: 2023
Předmět:
Zdroj: Chemosphere. 313:137502
ISSN: 0045-6535
Popis: About 13% and 7% of monitored groundwater stations in Europe exceed the permitted levels of nitrates (50 mg NO3- L-1) or pesticides (0.1 μg L-1), respectively. Although slow sand filtration can remove nitrates via denitrification when oxygen is limited, it requires an organic carbon source. The present study evaluates the performance of the use of wood pellets and granulated cork as carbon sources in bench-scale biofilters operated under water-saturated and water-unsaturated conditions for more than 400 days. The biofilters were monitored for nitrate (200 mg L-1) and pesticide (mecoprop, diuron, atrazine, and bromacil, each at a concentration of 5 μg L-1) attenuation, as well as for the formation of nitrite and pesticide transformation products. Microbiological characterization of each biofilter was also performed. The water-saturated wood biofilter achieved the best nitrate removal (>99%), while the cork biofilters lost all denitrification power over time (from 38% to no removal). The unsaturated biofilter columns were not effective for removing nitrates (20-30% removal). As for pesticides, all the biofilters achieved high removal rates of mecoprop and diuron (>99% and >75%, respectively). Atrazine removal was better in the wood-pellet biofilters than the cork ones (68-96% vs. 31-38%). Bromacil was only removed in the water-unsaturated cork biofilter (67%). However, a bromacil transformation product was formed there. The water-saturated wood biofilter contained the highest number of denitrifying microorganisms, with Methyloversatilis as the characteristic genus. Microbial composition could explain the high removal of pesticides and nitrates achieved in the wood-pellet biofilter. Overall, the results indicate that wood-pellet biofilters operated under water-saturated conditions are a good solution for treating groundwater contaminated with nitrates and pesticides.
The authors are grateful for the financial support of the European Union through the project LIFE18 ENV/ES/000199 and the Catalan DemoProject Democleanleach, CENTRE CERCA. ME acknowledges the funding received through the Beatriu de Pinós 2018 grant program (MSCA grant agreement number 801370). IDAEA-CSIC is a Severo Ochoa Center of Excellence (Spanish Ministry of Science and Innovation, Project CEX2018-000794-S). Finally, the authors wish to thank Yolanda Rodríguez and Albert Menéndez for their valuable help in the sampling process and chemical sample analysis and Yolanda Lucas for her technical assistance with the molecular biology analyses performed at the IRTA (Spain).
Databáze: OpenAIRE
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