Simultaneous sulfide and acetate oxidation under denitrifying conditions using an inverse fluidized bed reactor

✍ Scribed by Ricardo Beristain-Cardoso; Anne-Claire Texier; Reyes Sierra-Álvarez; Jim A Field; Elías Razo-Flores; Jorge Gómez

• Publisher: Wiley (John Wiley & Sons)
• Year: 2008
• Tongue: English
• Weight: 216 KB
• Volume: 83
• Category: Article
• ISSN: 0268-2575
• DOI: 10.1002/jctb.1921

✦ Synopsis

Abstract

BACKGROUND: Simultaneous removal of sulfur, nitrogen and carbon compounds from wastewaters is a commercially important biological process. The objective was to evaluate the influence of the CH~3~COO^−^/NO~3~^−^ molar ratio on the sulfide oxidation process using an inverse fluidized bed reactor (IFBR).

RESULTS: Three molar ratios of CH~3~COO^−^/NO~3~^−^ (0.85, 0.72 and 0.62) with a constant S^2−^/NO~3~^−^ molar ratio of 0.13 were evaluated. At a CH~3~COO^−^/NO~3~^−^ molar ratio of 0.85, the nitrate, acetate and sulfide removal efficiencies were approximately 100%. The N~2~ yield (g N~2~ g^−1^ NO~3~^−^‐N consumed) was 0.81. Acetate was mineralized, resulting in a yield of 0.65 g inorganic‐C g^−1^ CH~3~COO^−^‐C consumed. Sulfide was partially oxidized to S^0^, and 71% of the S^2−^ consumed was recovered as elemental sulfur by a settler installed in the IFBR. At a CH~3~COO^−^/NO~3~^−^ molar ratio of 0.72, the efficiencies of nitrate, acetate and sulfide consumption were of 100%, with N~2~ and inorganic‐C yields of 0.84 and 0.69, respectively. The sulfide was recovered as sulfate instead of S^0^, with a yield of 0.92 g SO~4~^2−^‐S g^−1^ S^2−^ consumed.

CONCLUSIONS: The CH~3~COO^−^/NO~3~^−^ molar ratio was shown to be an important parameter that can be used to control the fate of sulfide oxidation to either S^0^ or sulfate. In this study, the potential of denitrification for the simultaneous removal of organic matter, sulfide and nitrate from wastewaters was demonstrated, obtaining CO~2~, S^0^ and N~2~ as the major end products. Copyright © 2008 Society of Chemical Industry