Metabolic divergence in simultaneous biological removal of nitrate and sulfide for elemental sulfur production under temperature stress

Michal Sposob; Rune Bakke; Carlos Dinamarca

doi:10.1016/j.biortech.2017.02.122

Metabolic divergence in simultaneous biological removal of nitrate and sulfide for elemental sulfur production under temperature stress

Bioresour Technol. 2017 Jun:233:209-215. doi: 10.1016/j.biortech.2017.02.122. Epub 2017 Feb 28.

Authors

Michal Sposob¹, Rune Bakke², Carlos Dinamarca²

Affiliations

¹ University College of Southeast Norway, Kjølnes Ring 56, Porsgrunn 3918, Norway. Electronic address: michal.sposob@usn.no.
² University College of Southeast Norway, Kjølnes Ring 56, Porsgrunn 3918, Norway.

PMID: 28279914
DOI: 10.1016/j.biortech.2017.02.122

Abstract

The simultaneous removal of NO₃^- and HS^- at temperature stress (25-10°C) is evaluated here. An expanded granular sludge bed (EGSB) reactor was run over 120days at N/S molar ratio of 0.35 (for S⁰ production) under constant sulfur loading rate of 0.4kgS/m³d. The simultaneous removal of NO₃^- and HS^-, was achieved at applied conditions. Average HS^--S removal varied from 98 (25°C) to 89.2% at 10°C, with almost complete NO₃^- removal. Average S⁰ yield ranged from 83.7 at 25°C to 67% at 10°C. The temperature drop caused a decrease in granular sludge accumulated S⁰ fraction by nearly 2.5 times. Decreased temperature caused metabolic pathway change observed as higher SO₄^2- production, apparently allowing the biomass to obtain more energy per HS^- consumed. It is hypothesized that the metabolic shift is a natural response to compensate for temperature-induced changes in energy requirements.

Keywords: Autotrophic denitrification; Elemental sulfur recovery; Sulfate production; Sulfide removal; Temperature impact.

MeSH terms

Bioreactors
Nitrates / metabolism
Sulfides / metabolism
Sulfur / metabolism*
Temperature*

Substances

Nitrates
Sulfides
Sulfur