Feedback control method for estimating the oxygen uptake rate in activated sludge systems

Catunda, S.Y.C.; Deep, G.S.; Haandel, Adrianus C. van; Freire, Raimundo C. S.

doi:10.1109/19.779191

Cited by 11 publications

(6 citation statements)

References 2 publications

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“…The proposed method was inspired by the OUR estimation strategies applied in the monitoring of activated sludge reactors for environmental purposes, where fast switching On-Off valves are PWM commanded for pseudo-continuous OUR estimation. [19][20][21] In our case, the gas phase oxygen molar fraction is regulated by means of two independent gas supplies (oxygen and nitrogen). Such regulation is performed by two PWM driven valves allowing accurate control of the DO concentration.…”

Section: Methods Description and Modelizationmentioning

confidence: 99%

A simplified implementation of the stationary liquid mass balance method for on‐line OUR monitoring in animal cell cultures

Fontova

Lecina

López‐Repullo

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND Compared with other methods, the stationary liquid mass balance method for oxygen uptake rate (OUR) determination offers advantages in terms of estimation accuracy and reduction of stress. However, the need for sophisticated instrumentation, like mass flow controllers and gas analysers, has historically limited wider implementation of such a method. In this paper, a new simplified method based on inexpensive valves for the continuous estimation of OUR in animal cell cultures is evaluated. The determination of OUR values is based on accurate operation of the dissolved oxygen (DO) control loop and monitoring of its internal variables. RESULTS The method developed was tested empirically in 2 L bioreactor HEK293 batch cultures. OUR profiles obtained by a dynamic method, global mass balance method and the developed simplified method were monitored and compared. The results show how OUR profile obtained with the proposed method better follows the off‐line cell density determination. The OUR estimation frequency was also increased, improving the method capabilities and applications. The theoretical rationale of the method was extended to the sensitivity analysis which was analytically and numerically approached. CONCLUSIONS The results showed the proposed method to be not only cheap, but also a reliable alternative to monitor the metabolic activity in bioreactors in many biotechnological processes, being a useful tool for high cell density culture strategies implementation based on OUR monitoring. © 2017 Society of Chemical Industry

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Section: Methods Description and Modelizationmentioning

confidence: 99%

A simplified implementation of the stationary liquid mass balance method for on‐line OUR monitoring in animal cell cultures

Fontova

Lecina

López‐Repullo

et al. 2018

J of Chemical Tech & Biotech

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“…Triggering these aerators with a PWM control and assuming that the aeration cycle has a constant total period much shorter than the time constant associated with the oxygen transfer function, the K L a(q(k)) term in (3) and (4) can be approximated by [9]  max max The K max value can be experimentally estimated using DO concentration values measured with the aerator turned on. In this phase (aeration), a function representing the DO concentration with time can be obtained by solving (2), which results in [10] …”

Section: Oxygen Transfer Function Modelmentioning

confidence: 99%

“…Different methods to estimate OUR have been suggested in [9] and [11], and several estimation algorithms that can be used in development of software sensors have been summarized in [12].…”

Section: Estimation Of the Our And Do Concentrationmentioning

confidence: 99%

Dissolved oxygen PWM control and oxygen uptake rate estimation using Kalman Filter in activated sludge systems

Silva

Catunda

Neto

et al. 2010

2010 IEEE Instrumentation &Amp; Measurement Technology Conference Proceedings

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The measurement and utilization of the oxygen uptake rate (OUR), or respiration rate, is very important in biological wastewater treatment process. It provides information about the biological activity and can indicate the presence of the toxic elements able to corrupt the system. An alternative to the lack of OUR sensors is to use computer codes as software sensors for the estimation of respirometric activity, based on dissolved oxygen (DO) measurements. In this paper the OUR is estimated using Kalman Filter as a software sensor and the DO concentration is controlled by aerators of on-off type triggered by pulse wide modulation. Simulation and experimental estimations are performed on a bench scale aerobic reactor.

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“…Entretanto, como a aeração do reator é fornecida por meio de bombas do tipo liga-desliga e, portanto, não permitem o controle do fluxo de ar, é necessário acioná-las por meio de um sinal PWM para que elas possam ser utilizadas com propósitos de controle, conforme tem sido relatado em [2].…”

Section: Dinâmica De Aeraçãounclassified

Desenvolvimento de um modelo linear e projeto de um controlador para concentração de oxigênio dissolvido em um reator de lodo ativado em escala de bancada

Silva¹,

Catunda²,

Dórea³

2016

Proceeding Series of the Brazilian Society of Computational and Applied Mathematics

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Resumo. Este artigo propõe um modelo linear para o processo de oxigênio dissolvido em um reator de lodo ativado em escala de bancada aerado por bombas do tipo liga -desliga. Tal modelo é utilizado no projeto de um controlador proporcional-derivativo, via Lugar das Raízes, aplicado ao controle da concentração de oxigênio dissolvido. Simulações são apresentadas para ilustrar a validade do modelo proposto e avaliar o desempenho do controlador.Palavras-chave. O xigênio dissolvido, controle de processos, reator de lodo ativado, sistemas não lineares, modelo linear. IntroduçãoSistemas de lodo ativado têm sido comumente empregados no tratamento biológico de despejos domésticos e industriais. Em tais sistemas, colônias de bactérias, sob condições favoráveis, são responsáveis pela remoção da matéria orgânica presente nas águas residuais. Elas consomem o oxigênio dissolvido (OD) e o substrato orgânico disponíveis no licor misto (mistura de esgoto bruto e matéria biológica) e liberam dióxido de carbono e outros subprodutos de suas reações metabólicas. O oxigênio consumido é fornecido ao sistema por meio de aeradores. A principal dificuldade associada com a modelagem e o controle desses processos está relacionada com o comportamento não linear do sistema e com o grande número de parâmetros e estados que podem variar durante a sua operação. Entretanto, modelos reduzidos podem ser levados em consideração caso somente o estado a ser observado seja de interesse (por exemplo, o oxigênio dissolvido) [5]. A concentração de oxigênio dissolvido é uma das principais variáveis controladas nos 1 francisco

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Feedback control method for estimating the oxygen uptake rate in activated sludge systems

Cited by 11 publications

References 2 publications

A simplified implementation of the stationary liquid mass balance method for on‐line OUR monitoring in animal cell cultures

A simplified implementation of the stationary liquid mass balance method for on‐line OUR monitoring in animal cell cultures

Dissolved oxygen PWM control and oxygen uptake rate estimation using Kalman Filter in activated sludge systems

Desenvolvimento de um modelo linear e projeto de um controlador para concentração de oxigênio dissolvido em um reator de lodo ativado em escala de bancada

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