Sand filter

A sand filter or "bacteria bed" is a layer of sand that is used to clean the water of bacteria and other microorganisms.^[1] It is a type of filter.^[2]

A layer of sand or gravel is used when sewage goes through sewage treatment.^[1] Before sewage comes to the bacteria bed, it should already have gone through part of the sewage treatment.^[3] At the bacteria bed, sewage gets exposed to (or has contact with) air, while microorganisms make some change to that sewage.^[1] The oxygen in the water kills the microbes, which are anaerobic.

Sand Filter Media

Sand filter used for water treatment
Sand filters on a tomato farm in California
Rapid pressure filter 1=raw water, 2=filtered water, 3=tank, 4=outlet flushing water, 5=inlet flushing water, 6=retraction line, 7=scavenging air, 8=injector, 9=supporting layer, 10=filter sand, 11=flushing funnel, 12=ventilation

References

↑ ^1.0 ^1.1 ^1.2 "Definition of bacteria bed". The Free Dictionary. Retrieved 2007-07-26.
↑ "Slow Sand Filtration" (PDF). National Drinking Water Clearinghouse. Archived from the original (PDF) on 2019-07-13. Retrieved 2021-07-05.
↑ A. Rushton, A.S. Ward, R.G. Holdich 1996. Introduction to solid-liquid filtration and separation technology. Wiley VCH. ISBN 978-3-527-28613-3

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[Definition_of_bacteria_bed-1] 1.0 ^1.1 ^1.2 "Definition of bacteria bed". The Free Dictionary. Retrieved 2007-07-26.

[2] "Slow Sand Filtration" (PDF). National Drinking Water Clearinghouse. Archived from the original (PDF) on 2019-07-13. Retrieved 2021-07-05.

[3] A. Rushton, A.S. Ward, R.G. Holdich 1996. Introduction to solid-liquid filtration and separation technology. Wiley VCH. ISBN 978-3-527-28613-3

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