Investigating the kinetics of autotrophic denitrification with thiosulfate: Modeling the denitritation mechanisms and the effect of the acclimation of SO-NR cultures to nitrite

Abstract

In this work the kinetics of a number of sulfide-oxidizing nitrate-reducing (SO-NR) cultures acclimated and not acclimated to nitrite were characterized. Anoxic respirometry coupled to kinetic modeling of respirometric profiles was the methodology used to study the two-step denitrification associated to thiosulfate oxidation. Autotrophic denitritation was initially studied in a non-acclimated SO-NR culture to confirm that nitrite reduction kinetics could be described through a Haldane-type equation. Afterwards, a kinetic model describing the two-step denitrification (NO 3 -→ NO 2 -→ N 2 ) was calibrated and validated through the estimation of several kinetic parameters from the fitting of experimental respirometric profiles obtained using either nitrate or nitrite as electron acceptors for both acclimated and non-acclimated biomass. The model proposed was a multi-substrate model that considered all the species implicated in the process as well as the stoichiometry associated particularly to the biomass studied in this work. A comparison between the kinetic parameters with the biomass acclimated and nonacclimated to nitrite revealed a 7-fold increase of the Haldane nitrite inhibition constant in the acclimated biomass with respect to the non-acclimated while the nitrite half-saturation constant and the maximum specific growth rate remained almost unchanged. The Fisher Information Matrix method was used to obtain the confidence intervals and also to evaluate the sensitivity and the identifiability in model calibration of each kinetic parameter estimated.

Advances in the biological removal of sulphides from aqueous phase in anaerobic processes: A review

“…On the other hand, authors have used single-substrate kinetic models taking into account microbial growth rates associated only to a single pollutant biodegradation (Monod, Haldane and other kinetic equations) to describe biological processes (Mora et al, 2015). A drawback of single-substrate kinetic models is the inability to describe the potential limitations of other species such as nutrients or the electron acceptors.…”

Long-term performance evaluation of an anoxic sulfur oxidizing moving bed biofilm reactor under nitrate limited conditions

“…6,17 -S L −1 ). 5,24 The higher K s observed at N/S ratios of 0.3 and 0.1 (Fig. 5) were clearly due to the cultivation under NO 3 − limitation.…”

Feasibility Test of Autotrophic Denitrification of Industrial Wastewater in Sequencing Batch and Static Granular Bed Reactors

“…where is the substrate conversion rate in mg/L-hr, S is the concentration of substrate in mg/L, is the specific growth rate, X is the specific biomass concentration in mg/L, Researchers have studied the kinetics of autotrophic denitrification with thiosulfate. Despite the inhibiting concentration of NO2 -, the concentration of SO4 2displayed a gradually increasing tendency (Mora et al, 2015). The concentration of SO4 2reached a maximum level after a certain length of time and then maintained the maximum concentration.…”