Nitrous oxide and methane production from denitrifying woodchip bioreactors at three hydraulic residence times.
J Environ Manage
; 242: 290-297, 2019 Jul 15.
Article
en En
| MEDLINE
| ID: mdl-31054393
ABSTRACT
Denitrifying bioreactors remove nitrate (NO3-) from agricultural drainage and are slated to be an integral part of nitrogen reduction strategies in the Mississippi River Basin. However, incomplete denitrification can result in nitrous oxide (N2O) production and anaerobic conditions within bioreactors may be conducive to methane (CH4) production via methanogenesis. Greenhouse gas production has the potential to trade excess NO3- in surface water with excess greenhouses gases in the atmosphere. Our study examined N2O and CH4 production from pilot scale (6.38â¯m3) bioreactors across three hydraulic residence times (HRTs), 2, 8, and 16â¯h. Production was measured from both the surface of the bioreactors and dissolved in the bioreactor effluent. Nitrous oxide and CH4 was produced across all HRTs, with the majority dissolved in the effluent. Nitrous oxide production was significantly greater (Pâ¯<â¯0.05) from 2â¯h HRTs (478.43â¯mg N2O m-3 day-1) than from 8 (29.95â¯mg N2O m-3 day-1) and 16 (36.61â¯mg N2O m-3 day-1) hour HRTs. Methane production was significantly less (Pâ¯<â¯0.05) from 2â¯h HRTs (0.51â¯gâ¯C m3 day-1) compared to 8 (1.50â¯gâ¯C m3 day-1) and 16 (1.69â¯gâ¯C m3 day-1) hour HRTs. The 2â¯h HRTs had significantly greater (Pâ¯=â¯0.05) impacts to climate change compared to 8 and 16â¯h HRTs. Results from this study suggest managing HRTs between 6 and 8â¯h in field bioreactors could minimize total greenhouse gas production and maximize NO3- removal.
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Base de datos:
MEDLINE
Asunto principal:
Reactores Biológicos
/
Óxido Nitroso
País/Región como asunto:
America do norte
Idioma:
En
Revista:
J Environ Manage
Año:
2019
Tipo del documento:
Article