Identification and modelling of aerobic hydrolysis – application of optimal experimental design

Abstract

Hydrolysis mechanism plays a dominant role in the delicate balance of electron donor/ electron acceptor ratios in BNR and EBPR systems as an important carbon source. In this study, the surface-saturation-type hydrolysis kinetics was investigated based on respirometric measurements, within the context of the theoretical and the practical identifiability of mathematical models. The identifiable parameters of a selected model were derived from respirograms. In addition, the information from the experiments was evaluated on the basis of Optimal Experimental Design (OED) methodology for different initial conditions of the batch respirometric experiment.

COD fractionation and biodegradation kinetics of segregated domestic wastewater: black and grey water fractions

“…The OUR represents the process rate of oxygen utilization and dissolved oxygen, S O , is a significant model component in current models. 6,13 The OUR profiles generated during the respirometric experiments were used to yield the magnitude of the total biodegradable COD, C S for the tested wastewater samples. In fact, the OUR area above the endogenous respiration level gives the amount of oxygen, O 2 , corresponding to available biodegradable COD.…”

“…33,34 The AQUASIM simulation program (Swiss Federal Institute for Environmental Science and Technology, Switzerland) was used in model evaluations. 35 The kinetic and stoichiometric parameters of the model were estimated according to the procedure proposed by Insel et al 13 using the SIMPLEX algorithm. The total biodegradable COD (C S ) and its fractions, namely, the readily biodegradable COD (S S ), the rapidly hydrolysable COD (X S1 ), and the slowly hydrolysable COD (X S2 ) were calculated using the amount of oxygen utilized.…”

Evaluation of Municipal and Industrial Wastewater Treatment Sludge Stabilization in Istanbul

“…Similarly, after 20 days of aerobic sludge digestion, the heterotrophic active fraction of biomass was calculated with simulation and compared with DOC/TOC experiments conducted on sludge samples in order to find a correlation between the loss of heterotrophic active biomass fraction and the destruction of volatile suspended solids. The heterotrophic active biomass (X H ) concentrations were checked with batch oxygen uptake rate (OUR) experiments [15] conducted both on fresh and 20-day aerobically digested sludges. Briefly, the batch OUR experiments were initiated with sludges seeded with an acetate spike which corresponds to an initial concentration of 500 mg COD/L in a 1.5 L vessel [16].…”

Water quality modelling for small river basins

“…The trajectory sensitivities together with the matrices Q k ¼ diagðð1=s De Pauw, 2005), thus, maximizing F implies minimizing the estimation error. In fact, by inspecting the trajectory sensitivities the identifiability of the data/ model combination can be assessed and optimal experimental conditions can be designed to maximize the estimation accuracy (Insel et al, 2003;De Pauw, 2005;Checchi and Marsili-Libelli, 2005). The identifiability of a parameter subset is determined according to the following procedure: the parameters are ranked according to a global sensitivity index (Eq.…”

“…Table 4 illustrates the main criteria used in the literature (see e.g. Atkinson and Donev, 1992;Versyck et al, 1998;Petersen, 2000;Insel et al, 2003;De Pauw, 2005;Checchi and Marsili-Libelli, 2005) and their effect on the estimation. For the present study the most effective proved to be A, E and mod E.…”