The impact of increased loading rate on granular media, rapid depth filtration of wastewater

Williams, Gordon J.; Sheikh, Bahman; Holden, R.B.; Kouretas, T.; Nelson, Kara L.

doi:10.1016/j.watres.2007.06.018

Cited by 41 publications

(26 citation statements)

References 17 publications

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“…Turbidity can readily be removed by rapid sand filtration, a process which can be enhanced by coagulation-flocculation processes, due to enlargement of the particles, resulting in better removal in the granular medium, with the additional effect of some microbial removal (Williams et al, 2007;Gitis, 2008;Shirasaki et al, 2010). Coagulation-flocculation-filtration has also the potential to partially remove dissolved organic material, thus lowering the COD load (Odegaard et al, 2009).…”

Section: Process Parametersmentioning

confidence: 99%

Selection Criteria for Water Disinfection Techniques in Agricultural Practices

Haute

Sampers

Jacxsens

et al. 2013

Critical Reviews in Food Science and Nutrition

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This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology for pre- or postharvest applications. Introduced criteria were divided into three principal components: (i) criteria related to the technology and which relate to the disinfection efficiency, (ii) attention points for the management and proper operation, and (iii) necessities in order to sustain the operation with respect to the environment. The selection criteria may help the end user of the water disinfection technology to obtain a systematic insight into all relevant aspects to be considered for preliminary decision making on which technologies should be put to feasibility testing for water disinfection in pre- and postharvest practices of the fresh produce chain.

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Section: Process Parametersmentioning

confidence: 99%

Selection Criteria for Water Disinfection Techniques in Agricultural Practices

Haute

Sampers

Jacxsens

et al. 2013

Critical Reviews in Food Science and Nutrition

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“…Main advantages of direct rapid sand filtration systems are its simplicity and economical construction, operation, and maintenance using local materials and skills [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…The retention factor is related to various parameters of direct rapid sand filter as the removal mechanisms such as transport, straining, and adsorption leading to retention are summarized as the parameter. As one of the most important design parameters for direct rapid sand filtration, loading rate is closely related to the production capacity of a filter, the required filter surface area [6]. Although the relation between loading rate and retention factor is of great importance when applying the model, the impact of the loading rate on retention factor is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Impact of loading rate and filter height on the retention factor in the model of total coliform (TC) removal in direct rapid sand filtration

Liu

et al. 2014

Desalination and Water Treatment

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2015) Impact of loading rate and filter height on the retention factor in the model of total coliform (TC) removal in direct rapid sand filtration, Desalination and Water Treatment, 54:1, 140-146, A B S T R A C TAs a promising technology for wastewater reuse, direct rapid sand filtration has been widely used throughout the world, especially in arid developing and emerging countries. Retention factor describing the equilibrium between retained and mobile total coliform (TC) bacteria plays an important role in the model of TC removal in direct rapid sand filtration. Little attention has been given to the relationship between retention factor and loading rate as well as filter height, two critical parameters impacting retention factor. Therefore, the influence of loading rate as well as filter height on retention factor was discussed. Results showed that retention factor decreased dramatically with loading rate ranging from 9 to 15 m/h, but increased slightly as loading rate ranged from 5 to 9 m/h, which is a little different with the variation of suspended solids and total phosphorus removal efficiency. Retention factor decreased significantly with filter height of 0-30 cm and 120-150 cm, but reduced uniformly with filter height of 30-120 cm. It was deduced that the optimum loading rate and filter height may be 9 m/h and 90-120 cm, respectively. Increasing flocculant could overcome retention factor reduction resulted from higher loading rate or smaller filter height.

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“…Some studies have been conducted to evaluate the performance of filter media on removal of different pollutants from water and wastewater (Johnston 1999;Templeton et al 2007;Tansel and Vinal 2005;Williams et al 2007;Devi et al 2008;Remize et al 2009;Malakootian 2009). In these studies, however, no efficient indices have been applied to evaluate the performance of filter media and to compare the efficiencies of different media.…”

Section: Introductionmentioning

confidence: 99%

Application of modified qualitative index for surveillance of water-filtration process in turbidity removal by different media

Gholikandi¹,

Noorisepehr

Dehghanifard

et al. 2012

Int. J. Environ. Sci. Technol.

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Several media have been used in treatment plants, however, their efficiency for turbidity removal, which is determined by qualitative indices, has been considered. Current qualitative indices such as turbidity and escaping particle number could not completely measure the efficiency of the filtration system; therefore defining new qualitative indices is essential. In this study, the efficiency of two different dual media filters in turbidity removal was compared in different operating condition using qualitative indices. The pilot consisted of a filter column (1-m depth) in which the filter-1 was consisted of a layer of anthracite (450-mm depth) and a layer of silica sand (350-mm depth); and filter-2 had the same media characteristics except for the first layer that was light expanded clay aggregates (LECA). Turbidities of 10, 20, and 30 NTU, coagulant concentrations of 4, 8, and 12 ppm and filtration rates of 10, 15, and 20 m/h were considered as variables. Results showed that the media of filter-2 is a suitable substitute for the media of filter-1 (P value \ 0.05). Turbidity removal efficiencies in different condition were 79.97 ± 1.79 to 91.37 ± 1.23% for the filter-2 and 75.12 ± 2.75 to 86.82 ± 1.3% for the filter-1. The LECA layer efficiency in turbidity removal was independent of filtration rates and due to its low head loss; LECA can be used as a proper medium. Results also showed that the particle index was a suitable index as a substitute for turbidity and escaping particle number as indices.

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The impact of increased loading rate on granular media, rapid depth filtration of wastewater

Cited by 41 publications

References 17 publications

Selection Criteria for Water Disinfection Techniques in Agricultural Practices

Selection Criteria for Water Disinfection Techniques in Agricultural Practices

Impact of loading rate and filter height on the retention factor in the model of total coliform (TC) removal in direct rapid sand filtration

Application of modified qualitative index for surveillance of water-filtration process in turbidity removal by different media

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