Filter Backwashing Tests and Upflow Equalization

by A. Adler Hirsch,

Serial Information: Journal of the Sanitary Engineering Division, 1968, Vol. 94, Issue 1, Pg. 129-146

Document Type: Journal Paper


Suspended solids are determined in backwash samples collected every 15 sec at critical points in filters throughout the backwash operation. Eight plants were visited to observe some 23 variables. Cleansing action is decidedly nonuniform, being greatest under the sides of the troughs and decreasing toward the intertrough median. Corners generally washed most poorly. Disparity in upflow is caused by the directional influence of the troughs which negate the uniformity expected from the underdrains. Although various correctives are considered, only a V-shaped functionally perforated guidance baffle can be permanently effective.

Subject Headings: Filters | Backwashing | Turbidity | Solid mechanics | Drainage | Baffles (hydraulic)

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