Deciphering the influence of S/N ratio in a sulfite-driven autotrophic denitrification reactor.
Sci Total Environ
; 836: 155612, 2022 Aug 25.
Article
in En
| MEDLINE
| ID: mdl-35504375
ABSTRACT
Sulfur-based autotrophic denitrification is a cost-effective alternative to heterotrophic denitrification for nitrate removal due to no need of external organic carbon supply. Herein, sulfite-driven autotrophic denitrification (SDAD) was firstly established in a sequencing batch biofilm reactor treating high-strength nitrate-containing wastewater added by the sulfite. The nitrogen removal performance was mainly investigated under a molar ratio of sulfur-tonitrogen (S/N) ranging from 0.44 to 3.07 in a total of 180-day operation. Long-term experiment showed the optimal of S/N was found to be 2.63, much close to the stoichiometric value, achieving the highest autotrophic denitrification rate and complete total nitrogen removal efficiency (TNRE) with 92.4 ± 0.3%. Cyclical trial confirmed nitrate reduction and sulfite oxidation simultaneously occurred along with sulfate formation. Meanwhile, nitrite accumulation was observed at a very low S/N conditions. Microbial community analysis identified that Sulfurovum, Thiobacillus, and Thermomonas as key denitrifying sulfur-oxidizing bacteria responsible for SDAD. Moreover, the dynamic shift in functional microorganisms affected by influent S/N was also detected. Finally, the metabolic pathway of SDAD process was unraveled via the cooperative encoding of sulfite oxidases (Sor, Apr, Sat) and nitrate-reducing genes. This study sheds light on a new sulfur-cycle autotrophic denitrification process for the bioremediation of nitrate-contaminated wastewater.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Denitrification
/
Nitrogen
Language:
En
Journal:
Sci Total Environ
Year:
2022
Document type:
Article
Affiliation country:
China