Denitrifying sulfide removal process on high-salinity wastewaters in the presence of Halomonas sp.

Biological conversion of sulfide, acetate, and nitrate to, respectively, elemental sulfur (S⁰), carbon dioxide, and nitrogen-containing gas (such as N₂) at NaCl concentration of 35–70 g/L was achieved in an expanded granular sludge bed (EGSB) reactor. A C/N ratio of 1:1 was noted to achieve high sulfide removal and S⁰ conversion rate at high salinity. The extracellular polymeric substance (EPS) quantities were increased with NaCl concentration, being 11.4-mg/g volatile-suspended solids at 70 mg/L NaCl. The denitrifying sulfide removal (DSR) consortium incorporated Thauera sp. and Halomonas sp. as the heterotrophs and Azoarcus sp. being the autotrophs at high salinity condition. Halomonas sp. correlates with the enhanced DSR performance at high salinity.