filter bed

American  

noun

1. a pond or tank having a false bottom covered with sand and serving to filter river or pond waters.

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filter bed British  

noun

1. a layer of sand or gravel in a tank or reservoir through which a liquid is passed so as to purify it Compare bacteria bed

2. any layer of material through which a liquid is passed so as to filter it

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Etymology

Origin of filter bed

First recorded in 1870–75

Example Sentences

Chlorination, by decreasing the load on filter beds, has enabled the rate of filtration to be increased in some cases.

From Project Gutenberg

A series of thirty filter beds is included in the original scheme; and the water travels 73.3 m. from the source to Birmingham by gravity alone with a fall of about 170 ft.

From Project Gutenberg

A good filter bed should not pass more than from two to three gallons per hour for every square foot of surface, and it must therefore have a large area.

From Project Gutenberg

Intermittent Filtration.—Sewage may be purified mechanically and chemically by method of intermittent filtration by passing it through filter beds of gravel, sand, coke, cinders, or any such materials.

From Project Gutenberg

The city's filtration system is of special interest to engineers; it occupies 20 acres, has eight filter beds, and filters 15,000,000 gallons of water daily.

From Project Gutenberg