Biomass development in slow sand filters

Campos, Luiza C.; Su, Min; Graham, Nigel; Smith, Stephen R.

doi:10.1016/s0043-1354(02)00167-7

Cited by 106 publications

(69 citation statements)

References 10 publications

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“…After completion of the permeability experiments, dismantling of the spent BASSF specimens did not reveal growth of green algal mass in as was observed by Campos et al [18] in uncovered slow sand filter beds. The spent BASSF filter specimen (permeated with contaminated groundwater) is characterized by OM content of 4.2 %.…”

Section: Fig 1 Total Coliform and E Coli Removal By Bassfsupporting

confidence: 66%

Contaminants removal by bentonite amended slow sand filter

Rao¹,

Malini²,

Lydia³

et al. 2013

J. Water Chem. Technol.

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Section: Fig 1 Total Coliform and E Coli Removal By Bassfsupporting

confidence: 66%

Contaminants removal by bentonite amended slow sand filter

Rao¹,

Malini²,

Lydia³

et al. 2013

J. Water Chem. Technol.

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“…Relevant processes include adsorption, bio-oxidation, predation and scavenging. These processes have been hypothesized but have never been comprehensively verified [123,124]. Such a gap in knowledge pertaining to the optimal efficiency of SSFs hampers advances in their design.…”

Section: Biological Mediated Processes In Fe 0 Filtersmentioning

confidence: 99%

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Ndé-Tchoupé

Crane

Mwakabona

et al. 2015

Water

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Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media that are both low-cost and sourced from locally available materials has resulted in the widespread use of bone char. Since the early 1990s metallic iron (Fe 0 ) has received widespread use as both an adsorbent and a reducing agent for the removal of a wide range of contaminant species from water. The ion-selectivity of Fe 0 is dictated by the positively charged surface of iron (hydr)oxides at circumneutral pH. This suggests that Fe 0 could potentially be applied as suitable filter media for the negatively charged fluoride ion. This communication seeks to demonstrate from a theoretical basis and using empirical data from the literature the suitability of Fe 0 filters for fluoride removal. The work concludes that Fe 0 -bearing materials, such as steel wool, hold good promise as low-cost, readily available and highly effective decentralized fluoride treatment materials.

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“…It is believed that contaminant removal in SSF occurs mainly in the colmation layer or schmutzdecke -a biologically active layer or biofilm formed at the sand-water interface (Campos et al 2002).…”

Section: *Corresponding Authormentioning

confidence: 99%

Visualisation of the microbial colonisation of a slow sand filter using an Environmental Scanning Electron Microscope

Joubert¹,

Pillay²

2008

Electron. J. Biotechnol.

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Abbreviations: ESEM: environmental scanning electron microscopy SEM: scanning electron microscopy SSF: slow sand filtrationThe removal of contaminants in slow sand filters occurs mainly in the colmation layer or schmutzdecke -a biologically active layer consisting of algae, bacteria, diatoms and zooplankton. A ripening period of 6 -8 weeks is required for this layer to form, during which time filter performance is sub-optimal. In the current study, an environmental scanning electron microscope was used to visualise the ripening process of a pilot-scale slow sand filter over a period of eight weeks. To achieve this, sand particles were removed at weekly intervals and observed for biofilm development. Biological mechanisms of removal in slow sand filtration are not fully understood. A visualisation of the colonisation process would enhance the knowledge and understanding of these mechanisms. Colonisation of sand particles and increase in biomass was clearly seen during the ripening period. The mature, ripened filter exhibited a dense extracellular matrix consisting of a wide variety of microorganisms and their extracellular and breakdown products. This research demonstrated the successful use of an environmental scanning electron microscope to visualise the complex, heterogeneous nature of the schmutzdecke in a slow sand filter. Such knowledge could possibly lead to an increase in the application of slow sand filtration, especially for rural communities.

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Biomass development in slow sand filters

Cited by 106 publications

References 10 publications

Contaminants removal by bentonite amended slow sand filter

Contaminants removal by bentonite amended slow sand filter

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Visualisation of the microbial colonisation of a slow sand filter using an Environmental Scanning Electron Microscope

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