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 CH3COO-/ NO3- molar ratio on the sulfide oxidation process using an inverse fluidized bed reactor (IFBR). Results: Three molar ratios of CH3COO-/NO3- (0.85, 0.72 and 0.62) with a constant S2-/NO3- molar ratio of 0.13 were evaluated. At a CH3COO-/NO3- molar ratio of 0.85, the nitrate, acetate and sulfide removal efficiencies were approximately 100%. The N2 yield (g N2 g-1 NO3- -N consumed) was 0.81. Acetate was mineralized, resulting in a yield of 0.65 g inorganic-C g-1 CH3COO- -C consumed. Sulfide was partially oxidized to S0, and 71% of the S2- consumed was recovered as elemental sulfur by a settler installed in the IFBR. At a CH3COO-/ NO3- molar ratio of 0.72, the efficiencies of nitrate, acetate and sulfide consumption were of 100%, with N2 and inorganic-C yields of 0.84 and 0.69, respectively. The sulfide was recovered as sulfate instead of S0, with a yield of 0.92 g S04 2- -S g-1 S2- consumed. Conclusions: The CH3COO-/NO3 - molar ratio was shown to be an important parameter that can be used to control the fate of sulfide oxidation to either S0 or sulfate. In this study, the potential of denitrification for the simultaneous removal of organic matter, sulfide and nitrate from wastewaters was demonstrated, obtaining CO2, S0 and N2 as the major end products.
Original language | English (US) |
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Pages (from-to) | 1197-1203 |
Number of pages | 7 |
Journal | Journal of Chemical Technology and Biotechnology |
Volume | 83 |
Issue number | 9 |
DOIs | |
State | Published - Sep 2008 |
Keywords
- Denitrification
- Elemental sulfur
- Inverse fluidized bed reactor
- Sulfide oxidation
ASJC Scopus subject areas
- Biotechnology
- General Chemical Engineering
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Waste Management and Disposal
- Pollution
- Organic Chemistry
- Inorganic Chemistry