Improvement of nitrate and nitrite reduction rates prediction
Electron. j. biotechnol
;
11(3): 73-82, July 2008. ilus, graf, tab
Artigo
em Inglês
| LILACS
| ID: lil-531891
ABSTRACT
Reported models of denitrification rates integrate in an unique parameter the pH-dependent inhibition by HNO2 and the pH effect on the bacterial metabolic activity; furthermore, they do not quantify separately the pH effect on the nitrate and on the nitrite reduction rates. The goal of this work was to quantify both effects on the kinetics of nitrate and nitrite reduction to improve the models predictive value. Assays were performed at a pH range of 6.5-9.0 in batch reactors at 37ºC with an activated sludge. At the studied pH range and at below the HNO2 inhibitory concentration (0.004 mg L-1), the maximum nitrate reduction rate diminished 23 percent and 50 percent by decreasing or increasing, respectively, one pH unit from 8.0. The maximum nitrite reduction at pH 8.0 diminished 15 percent at pH 7.0 and 40 percent at pH 9.0. At HNO2 concentrations over the inhibitory concentration, except at pH > 8.0, the maximum nitrate reduction rate diminished 50 percent upon decreasing the pH from 8.0 to 7.0 or increasing it from 8.0 to 9.0. Inclusion of the pH effect in the reported models improved their predictive value; average deviations from the experimental data were reduced from 53 percent to 10.7 percent or 33.8 percent to 10.5 percent for nitrite and nitrate reduction rates, respectively.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Desnitrificação
/
Concentração de Íons de Hidrogênio
/
Nitratos
Tipo de estudo:
Estudo prognóstico
/
Fatores de risco
Idioma:
Inglês
Revista:
Electron. j. biotechnol
Assunto da revista:
Biotecnologia
Ano de publicação:
2008
Tipo de documento:
Artigo
/
Documento de projeto
País de afiliação:
Chile
Instituição/País de afiliação:
Universidad de Concepción/CL
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