The progression of flow rates in variable declining rate filter systems

Dąbrowski, Wojciech

doi:10.1002/aheh.200500647

Cited by 6 publications

(12 citation statements)

References 15 publications

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“…First different ratios q 1 /q avr of the maximum to average flow rates in the plant were assumed, and from them and the assumed value of Q, the required flow rate through the clean filter was calculated. Then the procedure developed by Di Bernardo [1] and then simplified by Dąbrowski [6] was used to calculate the parameters such as: c 2 , h 0 for three different values of time. Observation of head loss caused by recirculation of filtrate through porous media filters shows that compressibility of accumulated deposits is an important factor of friction to flow when approach velocities are increased [12,13].…”

Section: Experimental Principles and Methodsmentioning

confidence: 99%

“…Due to imperfections of operation of the filter plant, which could be minimised but never totally eliminated, the real parameters of operation H, h 0 differed somewhat from the computed values and were predicted as an average value from a series of measurements. After that the Di Bernardo [1] set of equations [6] was applied again to make the computations for the actual circumstances of the experiment. Finally the UBE model [9] was used to make similar computations.…”

Section: Experimental Principles and Methodsmentioning

confidence: 99%

“…According to the Di Bernardo [1] model, if the backwash starts for the same H the values of h 0 , should not depend on the kinetics of filter clogging and result from hydraulic interaction of the filters [6,8] . This was verified by laboratory and numerical results, based on the UBE model.…”

Section: Experimental Principles and Methodsmentioning

confidence: 99%

“…The model did not include any equation describing the kinetics of filter media clogging, so the design method is universal. The description of this model has been simplified recently by cutting the number of equations and unknowns [6]. An optimisation procedure of VDR filter plant operation has been proposed [7,8] which agree with results of computations performed on a unit bed element (UBE) mathematical model of (VDR) filters.…”

Section: Introductionmentioning

confidence: 91%

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Laboratory and numerical experiments into efficient management of VDR filter plants

Zielina

Dąbrowski

Mackie

2015

Environ. Protect. Eng.

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One of the operation rules of variable declining rate (VDR) filters states that the longest filtration runs are achieved when the highest flow through the most recently backwashed filter and the highest available head loss coincide. This rule has previously been published by Dąbrowski, who used a simplified mathematical model of VDR filters developed by Di Bernardo. However, until now no experimental verification of this optimisation approach has been presented. A series of tests were carried out on a laboratory VDR filter plant, using a suspension collected from an industrial sedimentation tank and using alum as a coagulant. The results of the experiments were compared with computations carried out according to a combined unit bed element (UBE)-phenomenological model of deep bed filtration adapted to VDR operation by Mackie and Zhao. It was confirmed that the longest filtration runs did indeed correspond to the pairs of the highest H and q1/qavr. The UBE-phenomenological model of deep bed filtration gave results of computations quite close to experimental results and improved the accuracy of calculations based on the theoretical model by Di Bernardo.

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Section: Experimental Principles and Methodsmentioning

confidence: 99%

Section: Experimental Principles and Methodsmentioning

confidence: 99%

Section: Experimental Principles and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

See 2 more Smart Citations

Laboratory and numerical experiments into efficient management of VDR filter plants

Zielina

Dąbrowski

Mackie

2015

Environ. Protect. Eng.

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“…The DR flow control is commonly used for economical reasons and due to that the quality of the filtered effluent is generally comparable with that of the filters regulated by the flow speed controllers (Dabrowski, 2006). On the design of these filters, a hydraulic load is generally fixed in order to guarantee that the maximum rate will not exceed 1.5 times the medium rate (Di Bernardo y Sabogal, 2009).…”

Section: Introductionmentioning

confidence: 99%

Influence of the Flow Control (Declining Rate – Constant Rate) on the Filtration Process in Drinking Water Treatment1

Perea-Torres

Torres–Lozada

Cruz-Vélez

2014

IyU

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La filtración rápida es un proceso complejo e importante dentro de los tratamientos convencionales de agua para potabilización,ya que es la última barrera física para retener partículas y controlar el riesgo microbiológico. En esteestudio se evaluó a escala piloto la influencia del control de flujo en el proceso de filtración del agua clarificada del río Cauca —planta de potabilización Puerto Mallarino de laciudad de Cali, Colombia—. Los resultados de la operacióna tasa declinante se compararon con los resultados de la operaciónprevia de la planta piloto en la modalidad de tasaconstante, las variables de control operacional de los filtros fueron turbiedad del agua filtrada y la pérdida de carga. En general, la operación a tasa declinante permitió un mejor desempeño de los filtros, pues se obtuvo una menor turbiedad en el agua filtrada durante el periodo de máxima eficiencia y una mejor evolución de la pérdida de carga. Tal comportamiento está asociado a una mejor distribución de los sólidos sobre el medio filtrante, lo que permite reducir el riesgo de traspaso de partículas a través del filtro.

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Particle Shapes in the Drinking Water Filtration Process

Zielina

2011

CLEAN Soil Air Water

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Depth filtration is still one of the most important water treatment processes. It remains difficult to model mathematically because of the complexity of the process and the impact of numerous suspension parameters. The shape of the grains and suspension particles or flocs are among these parameters. The results of theoretical calculations suggest their visible impact on filtration. The shape of the media grain is relatively easy to measure. The shapes of the flocs or suspension particles, which are commonly not perfectly spherical, are much more difficult to predict. However, a few apparatuses developed lasting recent years make this possible. The FPIA 3000, manufactured by Malvern Instruments, uses flow particle image analysis method to measure 26 shape parameters of the suspension particles. Experimental measurement of suspension particle shape after flocculation and after depth filtration has allowed us to answer the question regarding the possible application of this measuring technique in water filtration technology. The experiments have also provided us with detailed information about the shape of flocs and suspension particles in filtered water. High number of particles characterized by circularity lower than 0.8 was detected in flocculated water inflowing to the filter. The particles remained in the outflow was characterized by visibly higher circularity than the particles inflowing to the filter. The results revealed much better removal of the particles characterized by lower circularity during filtration, whereas relation between convexity of the particles and their removal efficiency was not so evident.

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The progression of flow rates in variable declining rate filter systems

Cited by 6 publications

References 15 publications

Laboratory and numerical experiments into efficient management of VDR filter plants

Laboratory and numerical experiments into efficient management of VDR filter plants

Influence of the Flow Control (Declining Rate – Constant Rate) on the Filtration Process in Drinking Water Treatment1

Particle Shapes in the Drinking Water Filtration Process

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