Descrição
In situ pulse respirometry was applied in an activated sludge bubble column treating
synthetic wastewater for the estimation of the (i) maximum specific oxygen consumption rate, (ii)
substrate affinity constant, (iii) biomass growth yield, (iv) maintenance coefficient, and (v) specific
endogenous respiration rate. Parameters obtained through respirometry were compared to those
obtained by the chemostat method, based on substrate and biomass measurements, under several
dilution rates. The low sensitivity of substrate measurement methods and the difficulties of sampling
heterogeneous biomass suspension are critical issues limiting the applicability of the chemostat
method. Additionally, the extensive time consuming nature of this method allows concluding that
chemostat method presents several disadvantages in comparison with in situ pulse respirometric
techniques. Parameters were obtained from respirograms by fitting ASM1 and ASM3 models, and from
experiments performed by injecting pulses of increasing substrate concentration. The injection of
pulses of increasing concentration was the most adequate method, with several advantages such as a
simpler experimental data interpretation and results with better confidence.
Considering the assessment and comparison of the experimental and calculation methods presented, it
is recommended that kinetic and stoichiometric parameters estimation in mixed aerobic cultures
should preferentially be performed by using in situ respirometric techniques.
; Ordaz, Alberto 
