6533b7d8fe1ef96bd1269a29

RESEARCH PRODUCT

Biological groundwater denitrification systems: Lab-scale trials aimed at nitrous oxide production and emission assessment

Vito Armando LaudicinaMarco CapodiciGaspare VivianiAlessia Avona

subject

Environmental EngineeringDenitrificationSettore AGR/13 - Chimica Agrariachemistry.chemical_element010501 environmental sciencesNitrogen cycle01 natural scienceschemistry.chemical_compoundPermeable reactive barriersBiological groundwater denitrificationEnvironmental ChemistryNitriteWaste Management and DisposalEffluentNitrogen cycle0105 earth and related environmental sciencesNitrous oxideSettore ICAR/03 - Ingegneria Sanitaria-AmbientaleBiotrench04 agricultural and veterinary sciencesNitrous oxidePollutionchemistryGreenhouse gasEnvironmental chemistry040103 agronomy & agriculture0401 agriculture forestry and fisheriesEnvironmental scienceCarbonGroundwater

description

Bio-trenches are a sustainable option for treating nitrate contamination in groundwater. However, a possible side effect of this technology is the production of nitrous oxide, a greenhouse gas that can be found both dissolved in the liquid effluent as well as emitted as off gas. The aim of this study was to analyze NO3 − removal and N2O production in lab-scale column trials. The column contained olive nut as organic carbon media. The experimental study was divided into three phases (I, II and III) each characterized by different inlet NO3 − concentrations (30, 50, 75 mg NO3-N L−1 respectively). Sampling ports deployed along the length of the column allowed to observe the denitrification process as well as the formation and consumption of intermediate products, such as nitrite (NO2 −) and nitrous oxide (N2O). In particular, it was observed that N2O production represent only a small fraction of removed NO3 − during Phase I and II, both for dissolved (0.007%) and emitted (0.003%) phase, and it was recorded a high denitrification efficiency, over 99%. Nevertheless, significantly higher values were recorded for Phase 3 concerning emitted phase (0.018%). This fact is due to increased inlet concentration which resulted in a carbon limitation and in a consequent decrease in denitrification efficiency (76%).

yearjournalcountryeditionlanguage
2018-07-01
10.1016/j.scitotenv.2018.02.260http://hdl.handle.net/10447/282605