Operation Factors of Autotrophic Denitrification with Elemental Sulfur as Terminal Product

Abstract

An anaerobic membrane bioreactor (UBF) with a total capacity of 3L was employed for treatment of sulfide and nitrate containing wastewater with elemental sulfur as terminal product. The effect of HRT and pH on substrate removal and elemental sulfur accumulation was researched when S/N ratio at 2.5. The influent concentration of S2-/HS-and NO3--N were 110mg•L-1and 20mg•L-1, respectively, during autotrophic denitrification. When HRT was between 7.41h and 6.83h and pH was between 6 and 7.5, HRT and pH has no effect on NO3--N and sulfide removal ratios, and at 97% and 100%, respectively, but elemental sulfur accumulation ratio was increased to 61% with HRT shorten. And low pH (pH at 7) was conducive to elemental sulfur accumulation with the ratio up to 62%. But further to reduce the pH would lead marginal increase in elemental sulfur accumulation ratio at 65%.