Optimal control of physical backwash strategy - towards the enhancement of membrane filtration process performance

Kalboussi, Nesrine; Harmand, Jérôme; Rapaport, Alain; Bayen, Térence; Ellouze, Fatma; Amar, N.

doi:10.1016/j.memsci.2017.09.053

Cited by 31 publications

(13 citation statements)

References 26 publications

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“…Therefore, it is necessary to compare the reversibility, which represents the backwash cleaning efficiency, in different backwash conditions. According to the membrane filtration model by Kalboussi et al [ 66 ], the mass of the cake layer tends towards a constant value as the number of filtration cycles increase. According to the TMP variation in dead-end filtration with periodic backwashes [ 53 , 67 ], the fouling resistance at the end of each filtration cycle would be in increasing trend with filtration cycles continuing, therefore the fouling condition before AB is much closer to that before the third CB.…”

Section: Resultsmentioning

confidence: 99%

Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment

Yang

Monnot

Ercolei³

et al. 2021

Membranes

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To improve membrane fouling management, the NaClO-assisted backwash has been developed to improve permeability maintenance and reduce the need for intensive chemical cleanings. This study is aimed to focus on the efficiency of NaClO-assisted backwash in real UF pilot scale and with periodic classic backwash (CB) and air backwash (AB). The impacts on hydraulic filtration performance, physicochemical properties of membrane material under different addition frequencies of NaClO, and the performance of chlorinated CB and AB will be discussed. In result, 10 mg Cl2 L−1 NaClO addition in backwash water is confirmed to greatly improve the overall filtration performance and backwash cleaning efficiency. One condition stands out from the other due to better control of irreversible fouling, less NaClO consumption in 10 years prediction, sustainable and adaptable filtration performance, and less potential damage on the physicochemical properties of the membrane. Additionally, it can be inferred from this experiment that frequent contact with NaClO induced some degradation on the PES-made UF membrane surface properties. To retain the best state of UF membrane on anti-fouling and qualified production, the optimized condition with more frequent NaClO contact was not suggested for long-term filtration.

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Section: Resultsmentioning

confidence: 99%

Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment

Yang

Monnot

Ercolei³

et al. 2021

Membranes

View full text Add to dashboard Cite

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“…where U denotes the set of measurable functions over [0, T ] taking values in [−1, 1]. The question of practical applicability of a control that takes values different to −1 and 1 relies on approximations with chattering controls [19] and is exposed in [11,12] (see also [2] in the context of fed-batch bioprocesses). Next, we consider the following hypotheses on the model.…”

Section: Model Description and Preliminary Resultsmentioning

confidence: 99%

“…For the practical implementation of the optimal control law (where only the values u = −1 and u = 1 can be applied) it is not possible to stay exactly on the singular arc m = m. But an approximation by a sequence of filtration/backwashing can be applied to stay on the vicinity of the singular arc. This sequence can be chosen so that the average value of m is m, which provides a good approximation of the optimal value as it has been tested in [11,12]. One may argue that the optimal control problem could be reformulated as a discrete time problem where the time step is the smallest period of switching between filtration and backwashing that could be applied in practice.…”

Section: Discussionmentioning

confidence: 99%

Optimal Control of Membrane-Filtration Systems

Kalboussi

Rapaport

Bayen

et al. 2019

IEEE Trans. Automat. Contr.

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This paper studies an optimal control problem related to membrane filtration processes. A simple mathematical model of membrane fouling is used to capture the dynamic behavior of the filtration process which consists in the attachment of matter onto the membrane during the filtration period and the detachment of matter during the cleaning period. We consider the maximization of the net production of a membrane filtration system (i.e. the filtrate) over a finite time horizon, where control variable is the sequence of filtration/backwashing cycles over the operation time of process. Based on the Pontryagin Maximum Principle, we characterize the optimal control strategy and show that it presents a singular arc. Moreover we prove the existence of an additional switching curve before reaching the terminal state, and also the possibility of having a dispersal curve as a locus where two different strategies are both optimal.

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“…[102] A backwash process is typically carried out to eliminate contaminants collected on the membrane. It is conducted when there is an increase in TMP and/or a decline in permeate flux [94]. The direction and flow from the backwash will dislocate the contaminants from the membrane surface and washed out through the discharge line.…”

Section: Fouling Type Chemical Cleaning and Findings Refmentioning

confidence: 99%

A Review on the Use of Membrane Technology Systems in Developing Countries

et al. 2021

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Fulfilling the demand of clean potable water to the general public has long been a challenging task in most developing countries due to various reasons. Large-scale membrane water treatment systems have proven to be successful in many advanced countries in the past two decades. This paves the way for developing countries to study the feasibility and adopt the utilization of membrane technology in water treatment. There are still many challenges to overcome, particularly on the much higher capital and operational cost of membrane technology compared to the conventional water treatment system. This review aims to delve into the progress of membrane technology for water treatment systems, particularly in developing countries. It first concentrates on membrane classification and its application in water treatment, including membrane technology progress for large-scale water treatment systems. Then, the fouling issue and ways to mitigate the fouling will be discussed. The feasibility of membrane technologies in developing countries was then evaluated, followed by a discussion on the challenges and opportunities of the membrane technology implementation. Finally, the current trend of membrane research was highlighted to address future perspectives of the membrane technologies for clean water production.

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Optimal control of physical backwash strategy - towards the enhancement of membrane filtration process performance

Cited by 31 publications

References 26 publications

Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment

Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment

Optimal Control of Membrane-Filtration Systems

A Review on the Use of Membrane Technology Systems in Developing Countries

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