Enhanced elemental sulfur recovery and nitrogen removal through coupling of sulfide-dependent denitrification and anammox processes during ammonium- and sulfide-laden waste stream treatment

Influence of anammox process on autotrophic denitrification was investigated in this study, during simultaneous ammonium, nitrate and sulfide treatment. Elemental sulfur production and nitrogen removal by sulfide-dependent denitrifier (S-den) and mixed culture (S-den-anammox) were compared. Accumulation of nitrite (100%) and elemental sulfur (46.3%) was achieved at pH 7.0 and 30 degrees C with S2O32-/NO3- ratio of 1:1 by autotrophic denitrifier. Enhanced elemental sulfur production (56.5%-99.5%) by autotrophic denitrifier was obtained after coupling with anammox process. Total nitrogen removal increased to 80.5% in mixed culture reactor, which was 72.0% in anammox reactor. N2O emission in anammox reactor was not affected (<0.5% gaseous nitrogen) after coupling with autotrophic denitrification. Therefore, this study demonstrated enhanced elemental sulfur recovery and nitrogen removal through coupling of sulfide-dependent denitrification and anammox processes, which might be a potential technology for water eutrophication and corrosion control, and atmospheric acid rain, PM2.5 and global warming control.