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Biogas‐based denitrification in a biotrickling filter: Influence of nitrate concentration and hydrogen sulfide
Author(s) -
López Juan C.,
Porca Estefanía,
Collins Gavin,
Pérez Rebeca,
RodríguezAlija Alberto,
Muñoz Raúl,
Quijano Guillermo
Publication year - 2017
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.26092
Subject(s) - denitrifying bacteria , denitrification , anoxic waters , chemistry , nitrate , electron donor , sulfide , biogas , population , hydrogen sulfide , environmental chemistry , nitrogen , nuclear chemistry , biology , ecology , sulfur , organic chemistry , catalysis , demography , sociology
The feasibility of NO 3 − removal by the synergistic action of a prevailing denitrifying anoxic methane oxidising (DAMO), and nitrate‐reducing and sulfide‐oxidising bacterial (NR‐SOB) consortium, using CH 4 and H 2 S from biogas as electron donors in a biotrickling filter was investigated. The influence of NO 3 − concentration on N 2 O production during this process was also evaluated. The results showed that NO 3 − was removed at rates up to 2.8 g m reactor −3 h −1 using CH 4 as electron donor. N 2 O production rates correlated with NO 3 − concentration in the liquid phase, with a 10‐fold increase in N 2 O production as NO 3 − concentration increased from 50 to 200 g m −3 . The use of H 2 S as co‐electron donor resulted in a 13‐fold increase in NO 3 − removal rates (∼18 gNO 3 − m −3 h −1 ) and complete denitrification under steady‐state conditions, which was supported by higher abundances of narG , nirK , and nosZ denitrifying genes. Although the relative abundance of the DAMO population in the consortium was reduced from 60% to 13% after H 2 S addition, CH 4 removals were not compromised and H 2 S removal efficiencies of 100% were achieved. This study confirmed (i) the feasibility of co‐oxidising CH 4 and H 2 S with denitrification, as well as (ii) the critical need to control NO 3 − concentration to minimize N 2 O production by anoxic denitrifiers. Biotechnol. Bioeng. 2017;114: 665–673. © 2016 Wiley Periodicals, Inc.