To study the effects of Fe chelate solution and nitrosyl-complex (Fe(II)EDTA-NO), which might be introduced in the simultaneous biodesulfurization and denitrification process, on the sulfate removal process, a sulfate reducing bacteria Desulfovibrio sp. CMX was investigated for its sulfate removal capacity in the presence of Fe chelate additives and Fe(II)EDTA-NO. Meanwhile, Fe(II)EDTA-NO reduction was also investigated. The addition of Fe(II)EDTA and Fe(III)EDTA could stimulate the sulfate reduction performance. Although Fe(II)EDTA-NO could inhibit the strain, CMX could survive by consuming lactate and recover its sulfate reducing activity after Fe(II)EDTA-NO removed. Sulfate reduction could be enhanced in higher Fe(II)EDTA-NO concentrations (2 and 4 mM) by lactate applied at the middle stage of the experiment, and 72.2% and 62.6% sulfate were removed in 182 h, respectively. In this study, above 90% Fe(II)EDTA-NO (0.25-4 mM) was removed less than 60 h, which was much faster than sulfate reduction. (C) 2013 Elsevier Ltd. All rights reserved.