Achieving enhanced filter backwashing with combined air scour and sub-fluidising water at pilot and operational scale

Chipps, Michael; Bauer, M. J.; Bayley, R.

doi:10.1016/s0015-1882(97)84020-7

Cited by 11 publications

(6 citation statements)

References 1 publication

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“…Various authors have emphasized the importance of backwashing on long‐term performance of biofilters 6 , 53 , 78 – 81 . Although some treatment plants use nonchlorinated backwash water for their biofilters, others are operated with chlorinated backwash water either for every backwashing or intermittently.…”

Section: Biological Performancementioning

confidence: 99%

“…Variou s au th ors h ave em ph asized th e im portan ce of backwash in g on lon g-term perform an ce of biofilters. 6,53,[78][79][80][81] Alth ou gh som e treatm en t plan ts u se n on ch lorin ated backwash water for th eir biofilters, oth ers are operated with ch lorin ated backwash water eith er for every backwash in g or in term itten tly. Th erefore, it is im portan t to u n derstan d h ow ch lorin ated backwash water affects BOM rem oval an d th e am ou n t of biom ass in th e filters.…”

Section: Filter Mediamentioning

confidence: 99%

See 1 more Smart Citation

Biological filtration for BOM and particle removal: a critical review

Urfer¹,

Huck²,

Booth³

et al. 1997

Journal AWWA

141

115

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The authors review key parameters and engineering variables influencing biological filtration and identify areas requiring further research. Biological filtration, an important process step for the production of microbially safe and aesthetically pleasing drinking water, has attracted increased attention within the water industry. In many cases, the most economical way to implement biological rapid filtration is to achieve biodegradable organic matter (BOM) removal and particle removal within the same filter unit, i.e., single‐stage biological filtration. This requires optimization of the filtration process, keeping in mind both treatment goals: BOM and particle removal. This article presents a critical review of the key parameters and engineering variables influencing the biological performance, as well as the conventional performance, of biologically active filters. Several areas requiring further research have been identified.

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Section: Biological Performancementioning

confidence: 99%

Section: Filter Mediamentioning

confidence: 99%

Biological filtration for BOM and particle removal: a critical review

Urfer¹,

Huck²,

Booth³

et al. 1997

Journal AWWA

141

115

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“…Outro problema que ocorre na retrolavagem são as perdas de água durante a sua operação, que, dependendo da forma de manutenção e do tempo utilizado pelo agricultor, pode atingir valores excessivos. Um dos aprimoramentos no processo foi estudado por CHIPPS et al (1995), que recomendaram a realização da retrolavagem com a introdução conjunta de ar e água com vazão abaixo do valor de fluidização do leito, o que garantiria a remoção das impurezas e manteria os valores de perda de carga próximos à condição de filtros pouco sujos, permitindo o desempenho do filtro por maior tempo. SUMMERFELT & CLEASBY (1996) aplicaram técnicas para calcular parâmetros hidráulicos de fluidização em leitos granulares, com o objetivo de desenvolver unidades de leitos fluidizados biológicos para a aplicação em aqüicultura.…”

Section: Retrolavagemunclassified

Filtros de areia aplicados à irrigação localizada: teoria e prática

Testezlaf

2008

Eng. Agríc.

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RESUMO:A aplicação de filtros de areia em sistemas de irrigação localizada é recomendada quando a água possui contaminação orgânica e de algas. O correto dimensionamento e manutenção desses equipamentos são essenciais para garantir o controle efetivo da qualidade da água de irrigação, visando a reduzir a obstrução de emissores, a manter a uniformidade de aplicação de água e a evitar o aumento nos custos de operação do sistema. Apesar da existência de informações técnicas sobre o projeto, a operação e a manutenção desses filtros na literatura, elas estão dispersas e com detalhamento insuficiente para permitir otimização do dimensionamento da estrutura hidráulica e da escolha do meio poroso a ser utilizado. Dessa forma, o objetivo deste trabalho é apresentar uma revisão de literatura, relacionando informações práticas com conhecimento científico existente, buscando induzir e ampliar as pesquisas sobre este tema e contribuir para que as funções operacionais estabelecidas para o equipamento sejam plenamente alcançadas. Espera-se, também, auxiliar na melhoria dos processos de filtração e de retrolavagem na irrigação agrícola e no desenvolvimento de procedimentos metodológicos de projeto e no uso racional desses dispositivos. PALAVRAS-CHAVE: filtração, obstrução de emissores, meios porosos. LOCALIZED IRRIGATION SAND FILTERS: THEORY AND PRACTICEABSTRACT: The application of sand filters in localized irrigation systems is recommended in the presence of organic and algae contamination. The proper design and maintenance of these equipments are essential to assure an effective water quality control, in order to reduce the emitters clogging, to keep its water application uniformity, and to prevent increasing in the system operation costs. Despite the existence of some references about design, operation and maintenance of these filters, they are dispersed, with not enough details to guarantee the optimization of its hydraulics structure design and the proper selection of porous media to be used. Therefore, the objective of this work was to report a current literature review, relating practical information with scientific knowledge. The content of this review would help to induce and intensify the research on this subject and to contribute so the operational functions for the equipment are reached. It is also expected to assist the improvement of the filtration and flushing processes in the agricultural irrigation and the development of original design procedures and the rational use of these devices. KEYWORDS: filtration, emitters clogging, porous media. INTRODUÇÃOO entupimento de emissores na irrigação localizada por contaminantes físicos, químicos e biológicos afeta o desempenho hidráulico, amplia os problemas de manutenção e, conseqüentemente, o custo de operação do sistema, reduzindo a uniformidade de distribuição da água. A obstrução dos emissores afeta negativamente a operação do sistema, reduzindo as chances de sucesso da irrigação e tornando a qualidade da água a principal preocupação no manejo de culturas irrigadas p...

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“…The three primary methods for backwashing filters are (1) water only, (2) air scour followed by water wash and (3) combined air and water wash [3]. The most effective method of backwashing filters is combined air and water at "collapse pulsing" [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…According to Chipps et al[4], if a combination air and water was used, the velocity of scour air was from 20 to 50 m/h while the velocity of water was in the range of 7-25 m/h. As a benchmark, the upward velocity of water at 30% expansion for BOPS and sand was determined by using Eq.…”

mentioning

confidence: 99%

Effective depth, initial head loss and backwashing criteria as the key factors of burned oil palm shell (BOPS) granular filtration

Jusoh

Ali

Halim

et al. 2009

Desalination and Water Treatment

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ab s t r ac tThese studies are mainly focused on effective depth, initial head loss and backwashing criteria that have been identified as the key factors in relation to the fundamental parameters and also, indicated possible operation performance. Granular filter media used in this study are limited to burned oil palm shell (BOPS) and sand. The study on the bed depth in relation to effluent over influent turbidities ratio (C e /C o ) has been found to exhibit an exponential relation which showed a strong correlation coefficient (R 2 = 0.9) for different effective sizes of BOPS (ES, 1.0-2.5 mm) and sand (ES, 0.4-0.9 mm). By approximating relatively constant C e /C o for both BOPS and sand at different effective sizes, an exponential equation (R 2 = 0.98) is proposed to link all effective bed depths. This enabled a determination of the effective depth of BOPS and sand media which were not executed in the experiment. Initial head loss of single media of BOPS and sand which involved comparison of different models, such as Ergun and modified Kozeny-Carmen equations with experimental results, at different flow rates, showed a good agreement with modified Kozeny-Carmen equation for non-sphere. In backwashing criteria, studies that showed the relation between the difference in granular settlement velocity with backwashing water velocity, confirmed that the best combination of dual-media are sand of ES = 0.5 mm with UC of 1.5 and BOPS of ES = 1.0 mm with UC of 1.3.

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Achieving enhanced filter backwashing with combined air scour and sub-fluidising water at pilot and operational scale

Cited by 11 publications

References 1 publication

Biological filtration for BOM and particle removal: a critical review

Biological filtration for BOM and particle removal: a critical review

Filtros de areia aplicados à irrigação localizada: teoria e prática

Effective depth, initial head loss and backwashing criteria as the key factors of burned oil palm shell (BOPS) granular filtration

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