The denitrifying sulifde removal (DSR) process with bio-granules comprising both heterotrophic and autotrophic denitriifers can simultaneously convert nitrate, sulifde and acetate species into di-nitrogen gas, elemental sulfur and carbon dioxide, respectively, at high loading rates. This study has determined that the reaction rate of sulifde oxidized into sulfur could be enhanced in the presence of 1,2-naphthoquinone-4-sulphonate (NQS). The presence of NQS mitigated the inhibi-tion effects of sulifde species on denitriifcation. Furthermore, the reaction rates of nitrate and acetate to nitrogen gas and CO2, respectively, were also promoted in the presence of NQS, thereby enhancing the performance of DSR granules. The advantages and disadvantages of applying the NQS-DSR process are discussed.