filter bed

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filter bed

[′fil·tər ‚bed]
(civil engineering)
A fill of pervious soil that provides a site for a septic field.
(engineering)
A contact bed used for filtering purposes.

filter bed

A bed of gravel, sand, or the like used to filter water or sewage; also see sand filter.
References in periodicals archive ?
To evaluate backwash performance, it was necessary to dirty the filter bed of the analyzed filters (F1, F2 and F3) by applying four filtration rates (TF20-20 [m.sup.3] [m.sup.-2] [h.sup.-1], TF40-40 [m.sup.3] [m.sup.-2] [h.sup.-1], TF60-60 [m.sup.3] [m.sup.-2] [h.sup.-1] and TF75-75 [m.sup.3] [m.sup.-2] [h.sup.-1]) in three silica sand granulometries (G1, G2 and G3), with a 4-h filtration in each experimental combination.
The sand granulometries, referred to as G1 (fine: effective diameter--[D.sub.10] = 0.55 mm and uniformity coefficient--UC = 1.34), G2 (medium: [D.sub.10] = 0.77 mm and UC = 1.28) and G3 (coarse: [D.sub.10] = 1.04 mm and UC = 1.36), were used with a fixed filter bed height of 0.35 m, according to the recommendations of the manufacturer.
After the filtration step, backwash trials were performed in each filter individually and the procedure consisted in applying a flow rate from the fourth filter of the module (FR) in the opposite direction of the filtration process, in order to generate a filter bed expansion of 25%, according to the guidelines of Brouckaert (2004), which corresponded to the height of 0.44 m.
Backwash was evaluated based on the collection of sand samples at different depths inside the filter bed (four sampling points in the filter bed profile).
1 and, based on its sum, the total mass of solids present in the filter bed ([MS.sub.Ftotal]) was estimated.
[MS.sub.Fi]--mass of solids present in the filter bed after filtration trial (degree of soiling) in each fraction of volume of the filtering layer i (g); and
2 was used to determine the mass of solids removed in each backwash trial in the filter bed individual layers ([MS.sub.Ri]) and, based on its sum, the total mass of solids removed in the backwash process ([MS.sub.Rtotal) was estimated.
[MS.sub.DRi]--mass of solids present in the filter bed after backwash trials, in each fraction of volume of the filtering layer i (g);
[E.sub.L] - cleaning efficiency for the entire filter bed (%).
AND b)The tender should have similar type of work experience successfully Maintained /Repairs 6 MGD filter Channels, Settling Tanks, Filter Beds, Pump Houses, Clarifier, Chlorine Plants, Washing of Filter Beds etc., maintained at least One year in any of the Government Departments/Government Undertakings, during the last Ten years i.e., not earlier than April-2008.
Name of Project: Attending repairs and strengthening of alum room and alum tanks at mir alam filter beds under mir alam filter beds section sub division i o and m division no xvii bhojagutta
Supply, Delivery and fixing of 55kw/75hp 415v 50hz 1440rpm tefc induction motors suitable for existing pumps of kirloskar make at thattikhana pump house in asif nagar filter beds, Under electrical and mechanical section,o&m division no.