Understanding nitrogen transformation using the ratio of nitrogen to argon in landfills under in-situ stabilisation

Understanding nitrogen transformation using the ratio of nitrogen to argon in landfills under in-situ stabilisation

Buisma-Yi, S.C. (TU Delft Geo-engineering)
Meza Ramos, P.N. (TU Delft Geo-engineering)
Oonk, Hans (Oonkay!)
Gebert, J. (TU Delft Geo-engineering)

2023

In the Netherlands, three full-scale pilots have been in operation for approximately five years to understand the effects of leachate recirculation or aeration on waste stabilisation. This study employs the ratio of N2 to Ar in the landfill gas in comparison to the ratio in atmospheric air to derive the share of N2 that originates from denitrification. We collected samples from the three pilot landfills from different gas wells, gas collector systems and from the total bulk extracted gas and measured its composition using gas chromatography. We estimated the aeration efficiency of the two landfills under in situ aeration based on the CO2/CH4 ratio as an indicator of aerobic processes. Denitrification dominated in the aerated landfills, with as much as 13% of N2 being explained by the net effect of denitrification, whereas the landfill under leachate recirculation showed a net ‘loss’ of N2, indicating N2 fixation to be a dominant mechanism. There was a seasonal variability of the balance between denitrification and N2 fixation in the aerated sites, likely caused by increased aeration efficiency and hence increased availability of NO3- for denitrification under summer conditions with lower moisture content in the cover soil, allowing for increased air ingress. No such variability was observed for the landfill under liquid recirculation. Future evaluation of the microbial community composition will further elucidate N transformation pathways in landfills under different in-situ stabilisation treatments.

denitrification
nitrogen fixation
aeration
leachate recirculation
tracer gas

http://resolver.tudelft.nl/uuid:b79da6c1-c72f-4d87-a4b8-32fac6177456

CISA Publisher, Cagliari, Italy

2024-04-09

Proceedings SARDINIA 2023: 19th International Waste Management and Landfill Symposium

19th International Symposium on Waste Management, Resource Recovery and Sustainable Landfilling, 2023-10-09 → 2023-10-13, Forte Village Resort, Santa Margherita di Pula, Italy

Sardinia Symposium Proceedings, 2282-0027

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

conference paper

© 2023 S.C. Buisma-Yi, P.N. Meza Ramos, Hans Oonk, J. Gebert