Elemental sulfur formation and nitrogen removal from wastewaters by autotrophic denitrifiers and anammox bacteria

• Denitrifying ammonium oxidation (DEAMOX) reactor was tested.
• Elemental sulfur (S0) was accumulated with nitrogen being removed as nitrogen gas.
• Autotrophic denitrifiers and anaerobic ammonium oxidation bacteria were grown.
• The sulfide to nitrate ratio of 1.31:1 could lead to excess accumulation of S0.
• Alishewanella, Thauera and Candidatus Anammoximicrobium were the key strains.

Elemental sulfur (S0) formation from and nitrogen removal on sulfide, nitrate and ammonium-laden wastewaters were achieved by denitrifying ammonium oxidation (DEAMOX) reactor with autotrophic denitrifiers and anaerobic ammonium oxidation (anammox) bacteria. The sulfide to nitrate ratio is a key process parameter for excess accumulation of S0 and a ratio of 1.31:1 is a proposed optimum. The Alishewanella, Thauera and Candidatus Anammoximicrobium present respectively the autotrophic denitrifiers and anammox bacteria for the reactor. DEAMOX is demonstrated promising biological process for treating organics-deficient (S+N) wastewaters with excess S0 production.