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Assessment of simultaneous autotrophic–heterotrophic denitrification with high removal of nitrogen, sulfur and carbon: optimization through response surface methodology
Author(s) -
Peirano Clio,
Guerrero Lorna,
Barahona Andrea,
Montalvo Silvio,
Huiliñir Cesar,
Da Silva Cristopher,
Borja Rafael
Publication year - 2020
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.6244
Subject(s) - denitrification , heterotroph , autotroph , sulfur , environmental chemistry , eutrophication , chemistry , nitrate , response surface methodology , nitrogen , organic matter , thiosulfate , flue gas desulfurization , aerobic denitrification , denitrifying bacteria , sulfate , bacteria , nutrient , chromatography , organic chemistry , biology , genetics
BACKGROUND Some liquid industrial wastes are rich in sulfur (S), nitrogen (N) and organic matter, causing eutrophication of lakes and rivers. These wastes also are highly toxic to aquatic organisms and pose serious health problems. Biological N removal is performed by denitrification. Heterotrophic denitrifiers oxidize organic matter to CO 2 gas and reduce nitrate (NO 3 − ) to N 2 gas, whereas autotrophic denitrifiers oxidize reduced S compounds by reducing nitrate. Thus, a simultaneous denitrification process will allow for the removal of all these elements. RESULTS A response surface methodology (RSM) was used to analyze the effects of the ratios heterotrophic:autotrophic bacteria (H:A, 0.2–1.9), the molar Ac − (Acetate):NO 3 − (0.2–1.05) and thiosulfate (S 2 O 3 2− ):NO 3 − (0.15–1.1) on the denitrification process. The highest concentrations of sulfate were obtained with H:A = 0.2; Ac − : NO 3 − = 1.05 and S 2 O 3 2− :NO 3 − = 0.91. CONCLUSION High NO 3 − (average 95.0 ± 3.3%) removals were obtained in all experiments, the optimal values predicted by the RSM were obtained at H:A = 0.54, Ac − :NO 3 − = 1.05 and S 2 O 3 2− :NO 3 − = 0.41. When analyzing the removal of Ac − , the recommended optimal operating values were: Ac − :NO 3 − = 1.05; H:A = 0.37 and S 2 O 3 2− :NO 3 − = 0.8–0.9. © 2019 Society of Chemical Industry