Feed sulfide (S2-) (0-1222 mg/L), phenol (500-1217 mg/L), diesel (0-700 mg/L), NH4 +-N (0-450 mg/L) and NO3(-)-N (750-2000 mg/L) were varied in eight separate reactors (R1 to R8) operated in fed batch mode at constant hydraulic retention time (HRT: 1.25 day). Once a pollutant was varied, concentrations of others were kept constant. Maximum conversion of S2- to S-0 occurred at the following influent concentrations: S2- 750 mg/L, phenol 750 mg/L, diesel 300 mg/L, NH4 + -N 350 mg/L and NO3--N 1000 mg/L. Elemental S-0 production initially increased with increase in feed S2-, phenol and diesel and decreased at beyond feed concentrations of 750, 750 and 300 mg/L respectively. More than 350 mg/L of influent NH4 + -N had detrimental effect on the oxidation of both organics and S2-. Conversion of S2- to SO42- was supported by higher load of NO3--N. Gas produced mostly (80-90%) consisted of N-2. Increase in suspended biomass was observed with increase in S2- load and attached biomass increased when organic load was increased.